EP4669938A1 - Del de commande avec schéma de modulation d'impulsions à cycle de service variable - Google Patents

Del de commande avec schéma de modulation d'impulsions à cycle de service variable

Info

Publication number
EP4669938A1
EP4669938A1 EP24705702.9A EP24705702A EP4669938A1 EP 4669938 A1 EP4669938 A1 EP 4669938A1 EP 24705702 A EP24705702 A EP 24705702A EP 4669938 A1 EP4669938 A1 EP 4669938A1
Authority
EP
European Patent Office
Prior art keywords
light
emitting diode
detector
light source
luminescent material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24705702.9A
Other languages
German (de)
English (en)
Inventor
Szu-Yu Huang
Samiul ISLAM
Henning ZIMMERMANN
Felix Schmidt
Celal Mohan OEGUEN
Tobias BAUMGARTNER
Till-Jonas Ostermann
Bernd Scherwath
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TrinamiX GmbH
Original Assignee
TrinamiX GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TrinamiX GmbH filed Critical TrinamiX GmbH
Publication of EP4669938A1 publication Critical patent/EP4669938A1/fr
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/0256—Compact construction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/28—Investigating the spectrum
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/20—Controlling the colour of the light
    • H05B45/28—Controlling the colour of the light using temperature feedback
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/32—Pulse-control circuits
    • H05B45/325—Pulse-width modulation [PWM]
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
    • H10W90/00—Package configurations
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/02—Details
    • G01J3/10—Arrangements of light sources specially adapted for spectrometry or colorimetry
    • G01J2003/102—Plural sources

Definitions

  • the invention relates to a spectrometer device for obtaining spectroscopic information on at least one object, specifically for analyzing a sample, and to a method of obtaining spectroscopic information on at least one object.
  • the invention further relates to a computer program, a computer-readable storage medium and to a non-transient computer-readable medium.
  • Such devices and methods can, in general, be used for investigating or monitoring purposes, in particular, in the infrared (IR) spectral region, especially in the near-infrared (NIR) spectral region, and in the visible (VIS) spectral region, e.g. in a spectral region allowing to mimic a human's ability of color sight.
  • IR infrared
  • NIR near-infrared
  • VIS visible
  • Spectrometer devices are known to be efficient tools for obtaining information on the spectral properties of an object, when emitting, irradiating, reflecting and/or absorbing light. Spectrometer devices, thus, may assist in analyzing samples or other tasks in which information on the spectral properties of an object is of interest.
  • spectral information is obtained via one or more detectors and one or more wavelength-selective optical elements, such as one or more dispersive optical elements, filters such as bandpass filters, prisms, gratings, interferometers, or the like.
  • the detectors may comprise any type of light-sensitive element, such as one or more single or multiple pixel detectors, line detectors or array detectors having one- or two-dimensional arrays of pixels.
  • spectrometer devices may comprise one or more light sources.
  • tunable light sources e.g. lasers, and/or broad-band emitting light sources are used, such as halogen-gas filled light bulbs and/or hot filaments.
  • other light sources such as light emitting diodes have also been proposed for the visible spectral region.
  • US 2010/208261 A1 describes a device for determining at least one optical property of a sample.
  • the device comprises a tunable excitation light source for applying excitation light to the sample.
  • the device furthermore comprises a detector for detecting detection light emerging from the sample.
  • the excitation light source comprises a light-emitting diode array, which is configured at least partly as a monolithic light-emitting diode array.
  • the monolithic light-emitting diode array comprises at least three light-emitting diodes each having a different emission spectrum.
  • US 8,164,050 B2 describes a multi-channel source assembly for downhole spectroscopy that has individual sources that generate optical signals across a spectral range of wavelengths.
  • a combining assembly optically combines the generated signals into a combined signal and a routing assembly that splits the combined signal into a reference channel and a measurement channel.
  • Control circuitry electrically coupled to the sources modulates each of the sources at unique or independent frequencies during operation.
  • US 7,061,618 B2 describes integrated spectroscopy systems, wherein in some examples, integrated tunable detectors, using one or multiple Fabry-Perot tunable filters, are provided. Other examples use integrated tunable sources combining one or multiple diodes, such as superluminescent light emitting diodes (SLED), and a Fabry Perot tunable filter or etalon.
  • SLED superluminescent light emitting diodes
  • US 5,475,221 A describes an optical device which uses an array of light emitting diodes, controlled by multiplexing schemes, to replace conventional broad band light sources in devices such as spectrometers.
  • spectrometer devices are subject to various internal and external influences, such as environmental influences, which may have an impact on the results of the spectroscopic measurements.
  • various calibration and/or correction methods are known. These calibration methods may be performed once or several times, such as under laboratory conditions, e.g. by the manufacturer.
  • a plurality of on-line calibration techniques are known which may be performed by performing one or more correction and/or calibration steps in between two spectroscopic measurements or even during the measurements.
  • US 09360366 B1 discloses a self-referencing spectrometer that simultaneously auto-calibrate and measure optical spectra of physical object utilizing shared aperture as optical inputs.
  • the concurrent measure and self-calibrate capabilities makes it possible as an attachment spectrometer on a mobile computing device without requiring an off-line calibration with an external reference light source.
  • the obtained spectral information and imagery captured can be distributed through the wireless communication networks.
  • DE 102014013848 B4 discloses a microspectrometer, in particular a NIR microspectrometer for mobile applications in battery-operated terminals, to overcome the nonminiaturization and handheld limitations of the aforementioned system configurations, a microspectrometer system, and a calibration method.
  • the miniaturized NIR spectrometer is to be designed without active temperature stabilization.
  • WO 2019/191698 A2 relates to a self-referenced spectrometer for providing simultaneous measurement of a background or reference spectral density and a sample or other spectral density.
  • the self-referenced spectrometer includes an interferometer optically coupled to receive an input beam and to direct the input beam along a first optical path to produce a first interfering beam and a second optical path to produce a second interfering beam, where each interfering beam is produced prior to an output of the interferometer.
  • the spectrometer further includes a detector optically coupled to simultaneously detect a first interference signal produced from the first interfering beam and a second interference signal produced from the second interfering beam, and a processor configured to process the first interference signal and the second interference signal and to utilize the second interference signal as a reference signal in processing the first interference signal.
  • US 20210293620 A1 discloses a spectrometer, comprising: an illumination device for illuminating a spectrometric measurement region; a detection unit for detecting electromagnetic radiation coming from the spectrometric measurement region; and a spectral element, which is arranged in the beam path between the illumination device and the detection unit.
  • the illumination device comprises: a light emitting diode having a first central wavelength, which is designed to emit first electromagnetic radiation having a first spectrum; and a luminescent element for converting a first component of the first electromagnetic radiation having the first spectrum into second electromagnetic radiation having a second spectrum.
  • the first central wavelength is 550 nm or 3000 nm or has a value between 550 nm and 3000 nm.
  • the first spectrum and the second spectrum have an overlap.
  • US 06667802 B2 discloses a method of calibrating a spectrographic inspection system.
  • the method comprises providing a plurality of packages, each of the plurality of packages containing a group of items, wherein each of the groups of items has a known composition, measuring the reflectance value of each of the groups of items and thereby obtaining a reference reflectance value set, normalizing the reference reflectance value set and thereby creating a normalized reference reflectance value set, and storing the normalized reference reflectance value set.
  • US 06717669 B2 discloses auto-calibrating spectrometers and methods that measure transmission or reflection versus wavelength of a sample without need for calibration for long periods of time. Reflection and transmission spectrometers along with auto-calibrating methods for use therewith are disclosed.
  • US 09448114 B2 discloses a spectrometer which comprises a plurality of isolated optical channels comprising a plurality of isolated optical paths. The isolated optical paths decrease cross-talk among the optical paths and allow the spectrometer to have a decreased length with increased resolution. In many embodiments, the isolated optical paths comprise isolated parallel optical paths that allow the length of the device to be decreased substantially.
  • each isolated optical path extends from a filter of a filter array, through a lens of a lens array, through a channel of a support array, to a region of a sensor array.
  • Each region of the sensor array comprises a plurality of sensor elements in which a location of the sensor element corresponds to the wavelength of light received based on an angle of light received at the location, the focal length of the lens and the central wavelength of the filter.
  • US 2010/148083 A1 discloses a spectrophotometer including a plurality of LEDs arranged in a circular array, each having a calibrated power input determined by the use of pulse width modulation and each having a unique wavelength band determined by the utilization of a unique fluorescent phosphor coating or lens.
  • At least one of the LEDs comprising a phosphor-free high energy UV LED.
  • Light reflected to the spectrophotometer is divided into predetermined wavelength ranges through the utilization of a linear variable filter and photo detectors wherein the analog signal from a photo detector is converted to a digital value through the use of auto- ranging gain technique.
  • EP 3961826 A1 discloses a light emitting device including a light source configured to emit a primary light, a first phosphor that absorbs the primary light and converts the primary light into a first wavelength-converted light having a wavelength longer than that of the primary light, and a second phosphor that absorbs the primary light and converts the primary light into a second wavelength-converted light having a wavelength longer than that of the primary light.
  • the temperature is known to have a significant impact on the results and the precision of the spectroscopic measurements. Temperature changes may arise due to external influences, such as to changes of the environmental temperature. Additionally or alternatively, temperature changes may arise due to internal influences, such as electrical currents and electrical resistances within the spectroscopic devices, e.g. due to electrical power dissipation. These temperature changes may arise on a short timescale and/or may arise in the form of long-term drifts.
  • an operation of the light- emitting diode causes a heat-up of the light-emitting diode junction due to the limited conversion efficiency of electrical power to optical power in the context of spectroscopic devices is limited significantly.
  • the light-conversion efficiency of the luminescent material may also be significantly low.
  • a spectrometer device for obtaining spectroscopic information on at least one object, a corresponding method, a computer program, a computer-readable storage medium and a non-transient computer-readable medium, with the features of the independent claims.
  • Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims as well as throughout the specification.
  • a spectrometer device for obtaining spectroscopic information on at least one object is disclosed.
  • the spectrometer device comprises: i.
  • At least one light source for generating illumination light for illuminating the object, the light source comprising at least one light-emitting diode for generating primary light and at least one luminescent material for light-conversion of the primary light into secondary light; ii. at least one detector for detecting detection light from the object and for generating at least one detector signal; iii.
  • At least one driving unit for driving the light source in a manner that the light-emitting diode is generating the primary light, wherein the light-emitting diode is driven with a pulse modulation scheme having a variable duty cycle for controlling an emission power of the secondary light, wherein the duty cycle is varied based on an influencing parameter having an influence on the light-conversion efficiency of the luminescent material; iv. at least one evaluation unit for evaluating the detector signal generated by the detector and for deriving the spectroscopic information on the object from the detector signal.
  • the term “spectrometer device” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an optical device configured for acquiring at least one item of spectral information on at least one object.
  • the at least one item of spectral information may refer to at least one optical property or optically measurable property which is determined as a function of a wavelength, for one or more different wavelengths.
  • the optical property or optically measurable property, as well as the at least one item of spectral information may relate to at least one property characterizing at least one of a transmission, an absorption, a reflection and an emission of the at least one object, either by itself or after illumination with external light.
  • the at least one optical property may be determined for one or more wavelengths.
  • the spectrometer device specifically may form an apparatus which is capable of recording a signal intensity with respect to the corresponding wavelength of a spectrum or a partition thereof, such as a wavelength interval, wherein the signal intensity may, specifically, be provided as an electrical signal which may be used for further evaluation.
  • the spectrometer device may be or may comprise a device which allows for a measurement of at least one spectrum, e.g. for the measurement of a spectral flux, specifically as a function of a wavelength or detection wavelength.
  • the spectrum may be acquired, as an example, in absolute units or in relative units, e.g. in relation to at least one reference measurement.
  • the acquisition of the at least one spectrum specifically may be performed either for a measurement of the spectral flux (unit W/nm) or for a measurement of a spectrum relative to at least one reference material (unit 1), which may describe the property of a material, e.g., reflectance over wavelength.
  • the reference measurement may be based on a reference light source, an optical reference path, a calculated reference signal, e.g. a calculated reference signal from literature, and/or on a reference device.
  • the at least one spectrometer device may be a diffusive reflective spectrometer device configured for acquiring spectral information from the light which is diffusively reflected by the at least one object, e.g. the at least one sample.
  • the at least one spectrometer device may be or may comprise an absorption- and/or transmission spectrometer.
  • measuring a spectrum with the spectrometer device may comprise measuring absorption in a transmission configuration.
  • the spectrometer device may be configured for measuring absorption in a transmission configuration.
  • the at least one spectrometer device may comprise at least one light source which, as an example, may be at least one of a tunable light source, a light source having at least one fixed emission wavelength and a broadband light source.
  • the spectrometer device further comprises at least one detector device configured for detecting light, such as light which is at least one of transmitted, reflected or emitted from the at least one object.
  • the spectrometer device further may comprise, as will be outlined in further detail below, at least one wavelength-selective element, such as at least one of a grating, a prism and a filter, e.g. a length variable filter having varying transmission properties over its lateral extension.
  • the wavelength-selective element may be used for separating incident light into a spectrum of constituent wavelength signals whose respective intensities are determined by employing a detector such as a detector having a detector array as described below in more detail.
  • the spectrometer device may be a portable spectrometer device.
  • portable as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to the property of at least one object of being moved by human force, such as by a single user.
  • the object characterized by the term “portable” may have a weight not exceeding 10 kg, specifically not exceeding 5 kg, more specifically not exceeding 1 kg or even not exceeding 500 g.
  • the dimensions of the object characterized by the term “portable” may be such that the object extends by no more than 0.3 m into any dimension, specifically by no more than 0.2 m into any dimension.
  • the object specifically, may have a volume of no more than 0.03 m3, specifically of no more than 0.01 m3, more specifically no more than 0.001 m3 or even no more than 500 mm 3 .
  • the portable spectrometer device may have dimensions of e.g.10 mm by 10 mm by 5 mm.
  • the portable spectrometer device may be part of a mobile device or may be attachable to a mobile device, such as a notebook computer, a tablet, a cell phone, such as a smart phone, a smartwatch and/or a wearable computer, also referred to as “wearable”, e.g. a body borne computer such as a wrist band or a watch.
  • a weight of the spectrometer device specifically the portable spectrometer device, may be in the range from 1 g to 100 g, more specifically in the range from 1 g to 10 g.
  • spectroscopic information also referred to as “spectral information” or as “an item of spectral information”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an item of information, e.g. on at least one object and/or radiation emitted by at least one object, characterizing at least one optical property of the object, more specifically at least one item of information characterizing, e.g. qualifying and/or quantifying, at least one of a transmission, an absorption, a reflection and an emission of the at least one object.
  • the at least one item of spectral information may comprise at least one intensity information, e.g. information on an intensity of light being at least one of transmitted, absorbed, reflected or emitted by the object, e.g. as a function of a wavelength or wavelength sub-range over one or more wavelengths, e.g. over a range of wavelengths.
  • the intensity information may correspond to or be derived from the signal intensity, specifically the electrical signal, recorded by the spectrometer device with respect to a wavelength or a range of wavelengths of the spectrum.
  • the spectrometer device specifically may be configured for acquiring at least one spectrum or at least a part of a spectrum of detection light propagating from the object to the spectrometer.
  • the spectrum may describe the radiometric unit of spectral flux, e.g. given in units of watt per nanometer (W / nm), or other units, e.g. as a function of the wavelength of the detection light.
  • the spectrum may describe the optical power of light, e.g. in the NIR spectral range, in a specific wavelength band.
  • the spectrum may contain one or more optical variables as a function of the wavelength, e.g. the power spectral density, electric signals derived by optical measurements and the like.
  • the spectrum may indicate, as an example, the power spectral density and/or the spectral flux of the object, e.g. of a sample, e.g.
  • the spectrum may comprise at least one measurable optical variable or property of the detection light and/or of the object, specifically as a function of the illumination light and/or the detection light.
  • the at least one measurable optical variable or property may comprise at least one at least one radiometric quantity, such as at least one of a spectral density, a power spectral density, a spectral flux, a radiant flux, a radiant intensity, a spectral radiant intensity, an irradiance, a spectral irradiance.
  • the spectrometer device may measure the irradiance in Watt per square meter (W / m 2 ), more specifically the spectral irradiance in Watt per square meter per nanometer (W / m 2 / nm). Based on the measured quantity the spectral flux in Watt per nanometer (W / nm) and/or the radiant flux in Watt (W) may be determined, e.g. calculated, by taking into account an area of the detector.
  • object as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an arbitrary body, chosen from a living object and a non-living object.
  • the at least one object may comprise one or more articles and/or one or more parts of an article, wherein the at least one article or the at least one part thereof may comprise at least one component which may provide a spectrum suitable for investigations.
  • the object may be or may comprise one or more living beings and/or one or more parts thereof, such as one or more body parts of a human being, e.g. a user, and/or an animal.
  • the object specifically may comprise at least one sample which may fully or partially be analyzed by spectroscopic methods.
  • the object may be or may comprise at least one of: human or animal skin; edibles, such as fruits; plastics and textile.
  • the object may be a sample to be under investigation.
  • the object may be an internal target, e.g. for performing at least one calibration scheme.
  • the term “light” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically specifically may refer, without limitation, to electromagnetic radiation in one or more of the infrared, the visible and the ultraviolet spectral range.
  • visible spectral range generally, refers to a spectral range of 380 nm to 760 nm.
  • IR infrared spectral range
  • NIR near infrared spectral range
  • MidIR mid infrared spectral range
  • FIR far infrared spectral range
  • light used for the typical purposes of the present invention is light in the infrared (IR) spectral range, more preferred, in the near infrared (NIR) and/or the mid infrared spectral range (MidIR), especially the light having a wavelength of 1 ⁇ m to 5 ⁇ m, preferably of 1 ⁇ m to 3 ⁇ m.
  • IR infrared
  • NIR near infrared
  • MidIR mid infrared spectral range
  • spectroscopy in other spectral ranges is also feasible and within the scope of the present invention.
  • the term “light source”, also referred to as an “illumination source”, as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an arbitrary device configured for generating or providing light in the sense of the above-mentioned definition.
  • the light source specifically may be or may comprise at least one electrical light source, such as an electrically driven light source.
  • the light source generally can be embodied in various ways.
  • the light source can be for example part of the spectrometer device in a housing of the spectrometer device.
  • the at least one light source can also be arranged outside a housing, for example as a separate light source.
  • the light source can be arranged separately from the object and illuminate the object from a distance.
  • various sources and paths of light are to be distinguished.
  • a nomenclature is used which, firstly, denotes light propagating from the light source to the object as “illuminating light” or “illumination light”.
  • light propagating from the object to the detector is denoted as “detection light”.
  • the detection light may comprise at least one of illumination light reflected by the object, illumination light scattered by the object, illumination light transmitted by the object, luminescence light generated by the object, e.g.
  • phosphorescence or fluorescence light generated by the object after optical, electrical or acoustic excitation of the object by the illumination light or the like.
  • the detection light may directly or indirectly be generated through the illumination of the object by the illumination light.
  • various light sources such as primary light sources and secondary light sources.
  • primary light also referred to as “pump light”
  • secondary light such as by using light conversion, e.g. through one or more phosphor materials.
  • the illumination light may be or may comprise at least one of the primary light or a part thereof, the secondary light or a part thereof, or a mixture of both. Consequently, the term “illuminate”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of exposing at least one element to light.
  • the light source comprises at least one light-emitting diode and at least one luminescent material for light-conversion of primary light generated by the light-emitting diode, wherein, specifically, the illumination light may be a combination of the primary light and light generated by the light-conversion by the luminescent material or light generated by the light conversion of the luminescent material, also referred to as secondary light.
  • the term “light-emitting diode” or briefly “LED”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an optoelectronic semiconductor device capable of emitting light when an electrical current flows through the device.
  • the optoelectronic semiconductor device may be configured for generating the light due to various physical processes, including one or more of spontaneous emission, induced emission, decay of metastable excited states and the like.
  • the light-emitting diode may comprise one or more of: a light-emitting diode based on spontaneous emission of light, in particular an organic light emitting diode, a light-emitting diode based on superluminescence (sLED), or a laser diode (LD).
  • the abbreviation “LED” will be used for any type of light-emitting diode.
  • the LED may comprise at least two layers of semiconductor material, wherein light may be generated at at least one interface between the at least two layers of semiconductor material, specifically due to a recombination of positive and negative electrical charges, e.g. due to electron-hole recombination.
  • the at least two layers of semiconductor material may have differing electrical properties, such as at least one of the layers being an n-doped semiconductor material and at least one of the layers being a p-doped semiconductor material.
  • the LED may comprise at least one pn-junction and/or at least one pin-set up. It shall be noted, however, that other device structures are feasible, too.
  • the at least one semiconductor material may specifically be or may comprise at least one inorganic semiconducting material. It shall be noted, however, that organic semiconducting materials may be used additionally or alternatively.
  • the LED may convert electrical current into light, specifically into the primary light, more specifically into blue primary light, as will be outlined in further detail below.
  • the LED thus, specifically may be a blue LED.
  • the LED may be configured for generating the primary light, also referred to as the “pump light”. Thus, the LED may also be referred to as the “pump LED”.
  • the LED specifically may comprise at least one LED chip and/or at least one LED die.
  • the semiconductor element of the LED may comprise an LED bare chip.
  • LEDs suitable for generating the primary light are known to the skilled person and may also be applied in the present invention.
  • p-n-diodes may be used.
  • one or more LEDs selected from the group of an LED on the basis of indium gallium nitride (InGaN), an LED on the basis of GaN, an LED on the basis of InGaN/GaN alloys or combinations thereof and/or other LEDs may be used.
  • quantum well LEDs may also be used, such as one or more quantum well LEDs on the basis of InGaN.
  • sLED Superluminescence LEDs
  • Quantum cascade lasers may be used.
  • the term “luminescence” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to the process of spontaneous emission of light by a substance not resulting from heat.
  • luminescence may refer to a cold-body radiation. More specifically, the luminescence may be initiated or excited by irradiation of light, in which case the luminescence is also referred to as “photoluminescence”.
  • the property of a material being capable of performing luminescence is referred to by the adjective “luminescent”.
  • the at least one luminescent material specifically may be a photoluminescent material, i.e. a material which is capable of emitting light after absorption of photons or excitation light.
  • the luminescent material may have a positive Stokes shift, which generally may refer to the fact that the secondary light is red-shifted with respect to the primary light.
  • the at least one luminescent material thus, may form at least one converter, also referred to as a light converter, transforming primary light into secondary light having different spectral properties as compared to the primary light.
  • a spectral width of the secondary light may be larger than a spectral width of the primary light, and/or a center of emission of the secondary light may be shifted, specifically red-shifted, compared to the primary light.
  • the at least one luminescent material may have an absorption in the ultraviolet and/or blue spectral range and an emission in the near-infrared and/or infrared spectral range.
  • the luminescent material or converter may form at least one component of a phosphor LED converging primary light or pump light, specifically in the blue spectral range, into light having a longer wavelength, e.g. in the near-infrared or infrared spectral range.
  • the conversion can occur via a dipole-allowed transition in the luminescent material, also referred to as fluorescence, and/or via a dipole-forbidden, thus long-lived, transition in the luminescent material, often also referred to as phosphorescence.
  • the luminescent material specifically, may, thus, form at least one converter or light converter.
  • the luminescent material may form at least one of a converter platelet, a luminescent and specifically a fluorescent coating on the LED and phosphor coating on the LED.
  • the luminescent material may, as an example, comprise one or more of the following materials: Cerium-doped YAG (YAG:Ce 3+ , or Y3Al5O12:Ce 3+ ); rare-earth-doped Sialons; copper- and aluminium-doped zinc sulfide (ZnS:Cu,Al).
  • the LED and the luminescent material, together, may form a so-called “phosphor LED”. Consequently, the term “phosphor light-emitting diode” or briefly “phosphor LED”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a combination of at least one light-emitting diode configured for generating primary light or pump light, and at least one luminescent material, also referred to as a “phosphor”, configured for light-conversion of the primary light generated by the light-emitting diode.
  • the phosphor LED may form a packaged LED light source, including the LED die, e.g. a blue LED emitting blue pump light, as well as the phosphor, which, as an example, fully or partially coats the LED, which is, as an example, configured for converting the primary light or blue light into light, in particular secondary light, having differing spectral properties, specifically into near-infrared light.
  • the phosphor LED may be packaged in one housing or may be unpackaged.
  • the LED and the at least one luminescent material for light-conversion of the primary light generated by the light-emitting diode may specifically be housed in a common housing.
  • the LED may also be an unhoused or bare LED which may fully or partially be covered with the luminescent material, such as by disposing one or more layers of the luminescent material on the LED die.
  • the phosphor LED generally, may form an emitter or light source by itself.
  • the at least one luminescent material specifically may be located with respect to the light-emitting diode such that a heat transfer from the light-emitting diode to the luminescent material is possible. More specifically, the luminescent material may be located such that a heat transfer by one or both of thermal radiation and heat conduction is possible, more preferably by heat conduction. Thus, as an example, the luminescent material may be in thermal contact and/or in physical contact with the light-emitting diode. As an example, the luminescent material may form one or more coatings or layers in contact with or in close proximity to the light-emitting diode, such as with one or more of the semiconductor materials of the light-emitting diode.
  • a temperature of the luminescent material and a temperature of the light-emitting diode may be coupled.
  • the at least one luminescent material specifically may form at least one layer.
  • various alternatives of positioning the luminescent material with respect to the light-emitting diode are feasible, alone or in combination.
  • the luminescent material e.g., at least one layer of the luminescent material, such as the phosphor, may be positioned directly on the light- emitting diode, which is also referred to as a “direct attach”, e.g.
  • the luminescent material may form at least one converter body, such as at least one converter disk, which may be placed on top of the LED, e.g. by adhesive attachment of the converter body to the LED. Additionally or alternatively, the luminescent material may also be placed in a remote fashion, such that the primary light from the LED has to pass an intermediate optical path before reaching the luminescent material.
  • the luminescent material in the remote placement may form a solid body or converter body, such as a disk or converter disk.
  • the luminescent material may also be a coating.
  • an object which is transmitting light e.g. a thin glass substrate, module window, comprising and/or being made of glass or plastics, may be coated with the phosphor.
  • a reflective surface may be coated with the phosphor. This could be a flat or rough mirror, which may comprise and/or be made of a high- reflective index material substrate, e.g.
  • the spectrometer device comprises at least one detector configured for detecting the detection light from the object, such as diffusely reflected light.
  • to detect is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to the process of at least one of determining, measuring and monitoring at least one parameter, qualitatively and/or quantitatively, such as at least one of a physical parameter, a chemical parameter and a biological parameter.
  • the physical parameter may be or may comprise an electrical parameter. Consequently, the term “detector” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an arbitrary device configured for detecting, i.e. for at least one of determining, measuring and monitoring, at least one parameter, qualitatively and/or quantitatively, such as at least one of a physical parameter, a chemical parameter and a biological parameter.
  • the detector may be configured for generating at least one detector signal, more specifically at least one electrical detector signal, such as an analogue and/or a digital detector signal, the detector signal providing information on the at least one parameter measured by the detector.
  • the detector signal may directly or indirectly be provided by the detector to an evaluation unit, such that the detector and the evaluation unit may be directly or indirectly connected.
  • the detector signal may be used as a “raw” detector signal and/or may be processed or preprocessed before further used, e.g.
  • the detector may comprise at least one processing device and/or at least one preprocessing device, such as at least one of an amplifier, an analogue/digital converter, an electrical filter and a Fourier transformation.
  • the detector is configured for detecting light propagating from the object to the spectrometer device or more specifically to the detector of the spectrometer device, which, according to the above-mentioned nomenclature, is referred to as “detection light”.
  • the detector may be or may comprise at least one optical detector.
  • the optical detector may be configured for determining at least one optical parameter, such as an intensity and/or a power of light by which at least one sensitive area of the detector is irradiated.
  • the optical detector may comprise at least one photosensitive element and/or at least one optical sensor, such as at least one of a photodiode, a photocell, a photosensitive resistor, a phototransistor, a thermophile sensor, a photoacoustic sensor, a pyroelectric sensor, a photomultiplier and a bolometer.
  • the detector thus, may be configured for generating at least one detector signal, more specifically at least one electrical detector signal, in the above- mentioned sense, providing information on at least one optical parameter, such as the power and/or intensity of light by which the detector or a sensitive area of the detector is illuminated.
  • the detector may comprise one single optically sensitive element or area or a plurality of optically sensitive elements or areas.
  • the detector may be or may comprise at least one detector array, more specifically an array of photosensitive elements, as will be outlined in further detail below.
  • Each of the photosensitive elements may comprise at least a photosensitive area which may be adapted for generating an electrical signal depending on the intensity of the incident light, wherein the electrical signal may, in particular, be provided to the evaluation unit, as will be outlined in further detail below.
  • the photosensitive area as comprised by each of the optically sensitive elements may, especially, be a single, uniform photosensitive area which is configured for receiving the incident light which impinges on the individual optically sensitive elements. However, other arrangements of the optically sensitive elements may also be conceivable.
  • the array of optically sensitive elements may be designed to generate detector signals, preferably electronic signals, associated with the intensity of the incident light which impinges on the individual optically sensitive elements.
  • the detector signal may be an analogue and/or a digital signal.
  • the electronic signals for adjacent pixelated sensors can, accordingly, be generated simultaneously or else in a temporally successive manner.
  • the individual optically sensitive elements may, preferably, be active pixel sensors which may be adapted to amplify the electronic signals prior to providing it to the evaluation unit.
  • the detector may comprise one or more signal processing devices, such as one or more filters and/or analogue-digital-converters for processing and/or preprocessing the electronic signals.
  • the detector comprises an array of optically sensitive elements
  • the detector may be selected from any known pixel sensor, in particular, from a pixelated organic camera element, preferably, a pixelated organic camera chip, or from a pixelated inorganic camera element, preferably, a pixelated inorganic camera chip, more preferably from a CCD chip or a CMOS chip, which are, commonly, used in various cameras nowadays.
  • the detector generally may be or comprise a photoconductor, in particular an inorganic photoconductor, especially PbS, PbSe, Ge, InGaAs, ext. InGaAs, InSb, or HgCdTe.
  • a photoconductor in particular an inorganic photoconductor, especially PbS, PbSe, Ge, InGaAs, ext. InGaAs, InSb, or HgCdTe.
  • it may comprise at least one of pyroelectric, bolometer or thermophile detector elements.
  • a camera chip having a matrix of 1 x N pixels or of M x N pixels may be used here, wherein, as an example, M may be ⁇ 10 and N may be in the range from 1 to 50, preferably from 2 to 20, more preferred from 5 to 10.
  • a monochrome camera element preferably a monochrome camera chip, may be used, wherein the monochrome camera element may be differently selected for each optically sensitive element, especially, in accordance with the varying wavelength along the series of the optical sensors.
  • the array may be adapted to provide a plurality of the electrical signals which may be generated by the photosensitive areas of the optically sensitive elements comprised by the array.
  • the electrical signals as provided by the array of the spectrometer device may be forwarded to the evaluation unit.
  • the spectrometer device may comprise at least one driving unit for electrically driving the light source.
  • the driving unit may comprise at least one current source for providing at least one predetermined current to the LED, wherein the current source specifically may be configured for adjusting or controlling a voltage applied to the LED in order to generate the predetermined current.
  • the driving unit may comprise one or more electrical components, such as integrated circuits, for driving the light source.
  • the driving unit may fully or partially be integrated into the light source or may be separated from the light source.
  • the driving unit may drive the light source in a manner that the light-emitting diode is generating the primary light.
  • the light-emitting diode may be driven with a pulse modulation scheme.
  • the pulse modulation scheme may have a variable duty cycle for controlling an emission power of the secondary light that is emitted by the luminescent material of the light source.
  • pulse modulation scheme is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a scheme for adapting and/or changing at least one parameter that is required as input for generating the secondary light.
  • the pulse modulation scheme may comprise a pulse duration modulation (PDM) – which may be also designated as pulse length modulation (PLM) or pulse width modulation (PWM).
  • PDM pulse duration modulation
  • PWM pulse width modulation
  • the pulse modulation scheme in the form of a pulse duration modulation may be a type of modulation in which a quantity, preferably an electrically measurable quantity (e.g.
  • the pulse modulation scheme may comprise a pulse duration modulation, which may be a modulation of a square wave signal in its pulse width, wherein the frequency remains constant.
  • the pulse modulation scheme it may be provided by the pulse modulation scheme that the duty cycle of a square wave pulse, in particular the duration of the pulse, is modulated at a constant frequency.
  • the term specifically may refer, without limitation, to pulse frequency modulation (PFM).
  • PFM pulse frequency modulation
  • the pulse modulation scheme in the form of a pulse frequency modulation may be a modulation of a square wave signal in its frequency, wherein the duration/width of the pulses (i.e.
  • the pulse code modulation scheme may also be a combination of a pulse duration modulation and a pulse frequency modulation, such that the pulse width and the pulse frequency is modulated.
  • the driving unit may operate having a duty cycle.
  • duty cycle as used herein, which may be also designated as “power cycle”, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically specifically may refer, without limitation, to a fraction of one period in which a signal and/or device is active, wherein the period is the time it takes for a signal and/or device to complete an on-and-off cycle.
  • the duty cycle may indicate the ratio of the pulse duration (which may be also designated as pulse width) to the period duration.
  • a duty cycle may be expressed as a percentage or a ratio.
  • the duty cycle may be a ⁇ 100 % duty cycle, e.g. a 50 % duty cycle.
  • the driving unit may be configured for being modulated at a predetermined frequency f.
  • the duty cycle may be a 60 % duty cycle.
  • a 60% duty cycle means the signal is on 60% of the time but off 40% of the time.
  • the “on time” for a 60% duty cycle could be a fraction of a second, a millisecond, etc., depending on the length of the period.
  • the duty cycle may be variably adapted based on an influencing parameter having an influence on the light-conversion efficiency of the luminescent material.
  • the term “influencing parameter” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a parameter that has an effect on the emission power of the secondary light that is emitted by the luminescent material of the light source.
  • the parameter may comprise a temperature value, in particular a temperature value representing the temperature of the luminescent material.
  • a temperature of at least one of the luminescent material or the light-emitting diode may be considered as influencing parameter.
  • the parameter may comprise an intensity value of primary light.
  • the spectrometer device comprises the at least one evaluation unit for evaluating at least one detector signal generated by the detector and for deriving the spectroscopic information on the object from the detector signal.
  • to evaluate is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to the process of processing at least one first item of information in order to generate at least one second item of information thereby. Consequently, the term “evaluation unit”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an arbitrary device or a combination of devices configured to evaluate or process at least one first item of information, in order to generate at least one second item of information thereof.
  • the evaluation unit may be configured for processing at least one input signal and to generate at least one output signal thereof.
  • the at least one input signal may comprise at least one detector signal provided directly or indirectly by the at least one detector.
  • the evaluation unit may be or may comprise one or more integrated circuits, such as one or more application-specific integrated circuits (ASICs), and/or one or more data processing devices, such as one or more of computers, digital signal processors (DSP), field programmable gate arrays (FPGA) preferably one or more microcomputers and/or microcontrollers.
  • ASICs application-specific integrated circuits
  • DSP digital signal processors
  • FPGA field programmable gate arrays
  • Additional components may be comprised, such as one or more preprocessing devices and/or data acquisition devices, such as one or more devices for receiving and/or preprocessing of the detector signals, such as one or more AD-converters and/or one or more filters.
  • the evaluation unit may comprise one or more data storage devices.
  • the evaluation unit may comprise one or more interfaces, such as one or more wireless interfaces and/or one or more wire-bound interfaces.
  • the evaluation unit may be adapted to execute at least one computer program, such as at least one computer program performing or supporting the step of generating the items of information.
  • one or more algorithms may be implemented which, by using the at least one detector signal may perform a predetermined transformation for deriving the spectroscopic information on the object, such as for deriving a corrected spectrum and/or for deriving at least one spectroscopic information describing at least one property of the object.
  • the evaluation unit may, particularly, comprise at least one data processing device, also referred to as a processor, in particular an electronic data processing device, which can be designed to generate the desired information by evaluating the detector signal.
  • the evaluation unit may use an arbitrary process for generating the required information, such as by calculation and/or using at least one stored and/or known relationship.
  • the evaluation unit specifically may be configured for performing at least one digital signal processing (DSP) technique on a primary detector signal or any secondary detector signal derived thereof, in particular at least one Fourier transformation. Additionally or alternatively, the evaluation unit may be configured for performing one or more further digital signal processing techniques on the primary detector signal or any secondary detector signal derived thereof, e.g. windowing, filtering, Goertzel algorithm, crosscorrelation and autocorrelation. Besides the detector signal one or a plurality of further parameters and/or items of information can influence said relationship. The relationship can be determined or determinable empirically, analytically or else semi-empirically.
  • DSP digital signal processing
  • the relationship may comprise at least one of a model or calibration curve, at least one set of calibration curves, at least one function or a combination of the possibilities mentioned.
  • One or a plurality of calibration curves can be stored for example in the form of a set of values and the associated function values thereof, for example in a data storage device and/or a table.
  • the at least one calibration curve can also be stored for example in parameterized form and/or as a functional equation.
  • the pulse modulation scheme may include pulsing the light-emitting diode at a driving frequency higher than 1/ ⁇ , preferably at least 5 times, more preferably at least 50 times, even more preferably at least 100 times and yet even more preferably at least 1000 times higher than 1/ ⁇ , wherein ⁇ is a time constant of the light source.
  • the time constant ⁇ may describe an operating condition of the light source when the driving state of the light source is changed.
  • time constant ⁇ is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a typical time interval describing a reorganization of the states of equilibrium, particularly of the luminescent material, when changing the at least one operating parameter.
  • the time constant ⁇ may describe a delay that occurs between the absorption of the at least one primary photon by the luminescent material and the emission of the at least one secondary photon by the luminescent material. This delay may be characterized by the so-called “characteristic time constant” ⁇ , also referred to as the “time constant”, the “decay time” or the “saturation time”.
  • the time constant ⁇ in these processes, may determine the 1/e-time of the process.
  • a first time constant may describe the typical time for reaching a saturation of the emission of converted light, such as the “growth constant”, which may depend on the intensity of the pump light.
  • a second time constant may describe the typical time of an afterglow of the luminescent material or converter, such as the “decay constant” or “decay”.
  • the time constant ⁇ may be related to a property of the light source, specifically a material characteristic of the light source, more specifically of the luminescent material used in the light source.
  • the term “property of the light source”, as used herein, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to at least one characteristic of a material of the light source, specifically of the luminescent material.
  • the “property” of the light source may, thus, be a “material property” of the light source, specifically of the luminescent material.
  • the property of the material of the light source may be related to a structure of at least one molecule of the light source, specifically of the luminescent material.
  • the property of the light source may be described by using temperature coefficients.
  • the temperature coefficients may differ for different wavelengths, thereby the temperature coefficients may depend on the wavelength.
  • Temperature coefficients related to a specific wavelength may be positive or negative and may vary in their absolute value based on the distribution of various energy states and Einstein coefficients.
  • the at least one time constant of the light source typically, depends on the light-emitting diode and the luminescent material.
  • the time constant of the light source ⁇ ⁇ ⁇ , ⁇ ⁇ , ⁇ ⁇ ⁇ may be derivable by considering the time constants of the light-emitting diode ⁇ ⁇ ⁇ and the luminescent material ⁇ ⁇ ⁇ . Any one of these time constants ⁇ ⁇ ( ⁇ , ⁇ ⁇ ) is dependent on the respective temperature and the wavelength. Typically ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ is much smaller than ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ in a manner that ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ is dominated by ⁇ ⁇ ⁇ on minor time scales. The determination of the time scales in this regime is of particular interest.
  • ⁇ ( ⁇ ) ⁇ ⁇ ⁇ ⁇ ( ⁇ )/ ⁇ + ⁇ ⁇ (1)
  • the signal or emission typically grows according to equation (2):
  • ⁇ ⁇ is the optical signal level at ⁇ ⁇ , when the forward current is applied/shut off.
  • ⁇ ⁇ is the reached optical signal level as ⁇ ⁇ 5.
  • the light-emitting diode may have a primary emission range at least partially located in the spectral range of 420 nm to 460 nm, more specifically in the range of 440 nm to 455 nm, more specifically at 440 nm.
  • the luminescent material may be phosphor.
  • the illumination light may have a spectral range at least partially located in the near-infrared spectral range, specifically in the spectral range from 1 to 3 ⁇ m, preferably from 1.3 to 2.5 ⁇ m, more preferably from 1.5 to 2.2 ⁇ m.
  • the time constant ⁇ may be at least one of: a decay constant ⁇ ⁇ of excited states in the luminescent material; or a growth constant ⁇ ⁇ of excited states in the luminescent material.
  • the term “decay constant” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a constant describing a decay of the signal and/or emission, particularly of the luminescent material.
  • growth constant as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a constant describing a growth of the signal and/or emission, particularly of the luminescent material.
  • the time constant ⁇ may depend on at least one of: the wavelength ⁇ of the illumination light; or the temperature ⁇ of the light source, specifically the luminescent material.
  • the time constant ⁇ may be considered for determining a temperature ⁇ of the light source, specifically of the luminescent material, by evaluating the time constant ⁇ , particularly for determining a temperature dependent drift of the light source, specifically of the luminescent material.
  • a power spectral density ⁇ of the light source, specifically the luminescent material may be derivable, wherein the power spectral density ⁇ of the light source may be considered when the spectroscopic information on the object is derived.
  • the light source may comprise at least one light-emitting diode for generating the primary light and at least one luminescent material for light-conversion of the primary light into the secondary light.
  • efficiency may signify the level of performance that uses the least amount of primary light to achieve the highest amount of secondary light.
  • the light-conversion efficiency may comprise the capability of a converting the primary light into the secondary light with a minimum amount or quantity of expense.
  • the pulse modulation scheme may be employed for modulating the power of primary light, such as blue light, during a measurement to keep the power of secondary light, such as infrared light, stable during one measurement.
  • the pulse modulation scheme may be configured to vary a driving frequency at which the light- emitting diode is pulsed.
  • the term specifically may refer, without limitation, to a predetermined electrical current through the LED for generating a desired light output of the light source and/or of the light-emitting diode.
  • the light source in particular the LED, may be driven with a predetermined forward current.
  • the forward current may be in the range of 10 mA to 500 mA, more specifically in the range of 100 mA to 300 mA.
  • the pulse modulation scheme may be configured for adjusting at least one of duty cycle, forward current or driving frequency dependent on a temperature of the light source, for example, dependent on a temperature of the luminescent material.
  • the pulse modulation scheme may comprises at least two different duty cycle values and/or at least two different driving frequency values and/or at least two different forward current values, wherein the values may be selected by considering a temperature of the light source. For instance, the values of duty cycle, forward current and/or driving frequency may be selected based on a temperature of the luminescent material. The adjustment of duty cycle, forward current and/or driving frequency may be performed during a measurement or between subsequent measurements. Thus, the temperature may function as an influencing parameter having an influence on the light- conversion efficiency of the luminescent material. The intensity of the pump light may be also used as influencing parameter.
  • continuous wave secondary light is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a continuous, temporally constant secondary light emission.
  • the light source specifically may comprise a phosphor light-emitting diode, also denoted as phosphor-LED.
  • the light-emitting diode specifically may have a primary emission range at least partially located in the spectral range of 250 nm to 940 nm.
  • the light-emitting diode specifically may have a primary emission range at least partially located in the spectral range of 420 nm to 460 nm, more specifically in the range of 440 nm to 455 nm, more specifically at 440 nm.
  • the illumination light specifically may have a spectral range at least partially located in the near- infrared spectral range, specifically in the spectral range from 1 to 3 ⁇ m, preferably from 1.3 to 2.5 ⁇ m, more preferably from 1.5 to 2.2 ⁇ m.
  • the differing spectral sensitivity may be implemented by using photosensitive elements having inherently differing spectral sensitivities, such as by using differing integrated filters and/or differing sensitive materials, such as semiconductor materials. Additionally or alternatively, the differing spectral sensitivity may be achieved by using one or more wavelength-selective elements in one or more beam paths of the detection light, such as one or more of a filter, a grating, a prism or the like, configured to allow forward differing spectral portions of the detection light from the object to reach the individual photosensitive elements, sequentially or simultaneously.
  • the spectrometer device may further comprise at least one wavelength- selective element.
  • wavelength-selective element is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to an arbitrary optical element which interacts with differing spectral portions of incident light in a different manner, e.g. by having at least one wavelength-dependent optical property, such as at least one wavelength-dependent optical property selected from the list consisting of a degree of reflection, a direction of reflection, a degree of refraction, a direction of refraction, an absorption, a transmission, an index of refraction.
  • the wavelength selection by the at least one wavelength-selective element may take place in the at least one beam path of the illumination light, thereby selecting and/or modifying a wavelength of the illumination of the object, and/or in the detection beam path of the detection light, thereby selecting and/or modifying a wavelength of detection, e.g. for the detector in general and/or for each of the photosensitive elements.
  • the at least one wavelength-selective element may comprise at least one of a wavelength-selective element disposed in a beam path of the illumination light and a wavelength-selective element disposed in a beam path of the detection light.
  • the wavelength-selective element specifically may be selected from the group of a tunable wavelength-selective element and a wavelength-selective element having a fixed transmission spectrum.
  • a tunable wavelength selective element as an example, differing wavelength ranges may be selected sequentially, whereas, by using a wavelength-selective element having a fixed transmission spectrum, the selection of the wavelength ranges may be fixed and may, however, be dependent e.g. on a detection position, thereby allowing, as an example, in the detection light beam path, for simultaneously exposing different detectors and/or different photosensitive elements of the detector to differing spectral ranges of light.
  • the at least one wavelength-selective element may comprise at least one of a filter, a grating, a prism, a plasmonic filter, a diffractive optical element and a metamaterial.
  • the wavelength-selective element may comprise one or more of a dispersive (e.g. prism), or diffractive (grating) element, or a detector with an inherently limited bandwidth of its spectral response.
  • the spectrometer device may comprise at least one filter element disposed in a beam path of the light from the object, i.e.
  • the filter element specifically may be configured such that each of the photosensitive elements is exposed to an individual spectral range of the light from the object.
  • a variable filter element may be used, the transmission of which depends on a position on the filter element, such that, when the variable filter element is placed on top of the array of photosensitive elements, the individual photosensitive elements are exposed to differing spectral ranges of the incident light, specifically the detection light from the object.
  • the at least one wavelength-selective element may comprise at least one of the following elements: an array of individual bandpass filters, an array of patterned filters, an MEMS-Interferometer, an MEMS-Fabry Perot interferometer. Further elements are feasible.
  • a method of obtaining spectroscopic information on at least one object comprises the following steps that may be performed in the given order. However, a different order may also be possible. In particular, one, more than one or even all of the method steps may be performed once or repeatedly. Further, the method steps may be performed successively or, alternatively, one or more of the method steps may be performed in a timely overlapping fashion or even in a parallel fashion and/or in a combined fashion. The method may further comprise additional method steps that are not listed.
  • the method comprises: a.
  • the light source comprising at least one light-emitting diode for generating primary light and at least one luminescent material for light-conversion of the primary light into secondary light
  • the driving unit is configured for driving the light source in a manner that the light-emitting diode is generating the primary light, wherein the light-emitting diode is driven with a pulse modulation scheme having a variable duty cycle for controlling an emission power of the secondary light, wherein the duty cycle is varied based on an influencing parameter having an influence on the light- conversion efficiency of the luminescent material;
  • a spectrometer device such as according to any one of the embodiments disclosed above and/or according to any one of the embodiments disclosed in further detail below, may be used.
  • the detector may comprise an array of photosensitive elements. Each of the photosensitive elements may be configured for generating at least one detector signal.
  • the method may comprise combining the detector signals for deriving the spectroscopic information. The method specifically may be performed on-line in the field.
  • on-line is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to the property of a process of being performed in the course of another process, such as during the other process, preferably without the necessity of being separately started or initiated by a user.
  • the method specifically at least step d. of the method, may be computer-implemented.
  • computer-implemented as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.
  • the term specifically may refer, without limitation, to a process which is fully or partially implemented by using a data processing means, such as data processing means comprising at least one processing unit.
  • the method, specifically step d. may be computer-implemented, or at least computer-controlled or computer-assisted, by using the evaluation unit of the spectrometer device.
  • a computer program comprising instructions which, when the program is executed by a spectrometer device according to the present invention, such as according to any one of the embodiments disclosed above and/or according to any one of the embodiments disclosed in further detail below, cause the spectrometer device to perform the method according to the present invention, such as according to any one of the embodiments disclosed above and/or according to any one of the embodiments disclosed in further detail below.
  • a computer-readable storage medium specifically a non-transient computer-readable medium, comprising instructions which, when the instructions are executed by a spectrometer device according to the present invention, such as according to any one of the embodiments disclosed above and/or according to any one of the embodiments disclosed in further detail below, cause the spectrometer device to perform the method according to the present invention, such as according to any one of the embodiments disclosed above and/or according to any one of the embodiments disclosed in further detail below.
  • the terms “computer-readable data carrier”, “computer-readable storage medium” and “non-transient computer-readable medium” are broad term and are to be given their ordinary and customary meaning to a person of ordinary skill in the art and are not to be limited to a special or customized meaning.
  • the terms specifically may refer, without limitation, to data storage means, specifically non-transitory data storage means, such as a hardware storage medium having stored thereon computer-executable instructions.
  • the computer- readable data carrier or storage medium or computer-readable medium specifically may be or may comprise a storage medium such as a random-access memory (RAM) and/or a read-only memory (ROM).
  • the method according to any one of the embodiments described above and/or according to any one of the embodiments described in further detail below may fully or partially be at least one of computer-controlled, computer-implemented, and computer- assisted, e.g. by using one or more computer programs running on at least one processor, e.g., at least one processor of the spectrometer device, e.g. of at least one processor integrated within the detector and/or within the evaluation unit.
  • at least step d. of the method may be at least one of computer-controlled, computer-implemented, and computer-assisted.
  • steps of the method may also fully or partially be at least one of computer-controlled, computer-implemented, and computer-assisted, such as one or more of steps a., b., c. and d.
  • computer-readable data carrier “computer-readable storage medium” and “non-transient computer-readable medium” are broad term and are to be given their ordinary and customary meaning to a person of ordinary skill in the art and are not to be limited to a special or customized meaning.
  • the terms specifically may refer, without limitation, to data storage means, specifically non-transitory data storage means, such as a hardware storage medium having stored thereon computer-executable instructions.
  • the computer- readable data carrier or storage medium or computer-readable medium specifically may be or may comprise a storage medium such as a random-access memory (RAM) and/or a read-only memory (ROM).
  • RAM random-access memory
  • ROM read-only memory
  • the spectrometer device and the method according to the present invention in one or more of the above-mentioned embodiments and/or in one or more of the embodiments described in further detail below, provide a large number of advantages over known devices and methods of similar kind.
  • Embodiments in accordance with the present invention may consider that a phosphor LED can be an instable system since the optical efficiency of the LED junction drops with increasing temperature during the operation. Further, the spectrum of the phosphor LED is also strongly affected by the temperature of the phosphor.
  • the operation of the LED causes a heat-up of the junction due to the limited conversion efficiency of electrical to optical power on order of 50 percent.
  • the conversion efficiency of blue light into IR light is on the order below 10 percent.
  • due to the decrease of the LED forward voltage at a given constant operation current reduces the input electrical power into the pump LED.
  • the radiation power drop of the whole emitter is trifold.
  • thermal equilibrium may be reached when heat transfer to the environment equals the heat dissipation in the system. Therefore, upon start-up, the temperature rises from ambient temperature to thermal equilibrium, which strongly influences the emission spectrum in terms of a change of the emitted power spectral density.
  • An objective of the modulation in particular by using a pulse modulation scheme, may be a constant (or arbitrary-shaped) IR power emission.
  • a figure of merit in this regard may be the deviation of the emitted IR power over time, compared to a target curve.
  • a measure of deviation e.g., the standard deviation, variance, maximum deviation and/or average absolute deviation might be used.
  • One or multiple operation parameters of the pump LED may be changed over time. For instance, operation parameters might be the duty cycle, the forward current and/or the pulse shape. The change might be described by a polynomial of order N, exponential, or other functions. Parameters of the functions may be changed by means of standard optimization algorithms, e.g.
  • the operation parameter setting may be applied in the factory, where calibration factors can be applied in the field.
  • parameters can be calculated in the field by monitoring the output power over time.
  • an on-line correction or calibration for temperature changes may be performed, and, thus, may allow for correcting the detector signal, specifically the spectrum or the spectral information derived thereof.
  • the use of phosphor LEDs instead of or in addition to conventional thermal emitters such as incandescent lamps with a tungsten wire as a light source may provide for several advantages.
  • thermal emitters may provide for a flat spectrum, low temperature dependency and a high power spectral density even at long wavelengths, such as in the NIR range
  • thermal emitters typically are not well-suited for large-volume spectrometer production.
  • a high complexity of the manufacturing process a low conversion efficiency from electrical to optical power and physical limitations in miniaturization are to be noted as disadvantages for thermal emitters.
  • LEDs specifically phosphor LEDs, these disadvantages may be overcome.
  • LEDs have proven to be reliable light sources, such as standardized light sources in the visible light regime.
  • broadband light sources may be provided by using one or more phosphor LEDs in the spectrometer device, comprising the at least one light-emitting diode and the at least one luminescent material or phosphor.
  • a white light source may be created and/or a broadband light source in the infrared range, specifically in the NIR range.
  • the phosphor may convert photons having a shorter wavelength, and, thus, a higher energy, into photons having a longer wavelength or lower energy, e.g. by transferring a portion of the primary photon energy to the phosphor material, such as to the phosphor lattice.
  • the luminescent material may be configured for absorbing one or more primary photons generated by the light-emitting diode and may, in reaction to this absorption, emit one or more secondary photons.
  • the emission of the secondary photons may take place instantaneously or after a delay or decay time.
  • the luminescent material may be or may comprise at least one of a phosphorescent and a fluorescent material.
  • the phosphorescence may lead to the effect that after turning off the primary light, such as the short-wavelength or high energy pump light, the luminescent material may emit the secondary light, such as the long wavelength light, for a characteristic life time, e.g., due to a forbidden quantum-optical transition or forbidden dipole transition.
  • the emission of the secondary light may take place over a forbidden transition, such as a forbidden dipole transition, having a longer lifetime than e.g. spontaneous dipole allowed transition, as may be the case in many fluorescent materials.
  • a luminescent material may be used, specifically a phosphorescent material, having an absorption in the blue spectral range and an emission in the infrared spectral range.
  • luminescent materials may be used capable of converting blue primary light or pump light, having a wavelength of e.g.440 nm, into near- infrared secondary light, e.g. secondary light having a wavelength in the range of 1 to 3 ⁇ m, preferably from 1.3 to 2.5 ⁇ m, more preferably from 1.5 to 2.2 ⁇ m.
  • the primary light or pump light may generated by an infrared LED with a wavelength in the range from 850 nm to 940 nm, which may then be converted by the luminescent material into near-infrared secondary light having a wavelength in the range of 1 to 3 ⁇ m, preferably from 1.3 to 2.5 ⁇ m, more preferably from 1.5 to 2.2 ⁇ m.
  • the phosphor LED comprising the at least one light-emitting diode and the at least one luminescent material, may be embodied as a single element.
  • the phosphor LED may comprise multiple sub-components.
  • the phosphor LED may comprise one or more functional components, such as the LED die comprising at least one junction between at least two semiconductor regions, such as at least one p-n-transition.
  • the primary light may be generated, such as the short-wavelength pump light, e.g. in the blue spectral range.
  • the phosphor LED may comprise the at least one luminescent material, specifically the at least one phosphorescent material, which may, specifically, be placed directly on top of the LED die and which may convert the primary light, specifically the pump light, into the secondary light, specifically into the long-wavelength near-infrared light.
  • the phosphor LED may comprise one or more substrates, specifically one or more electrically insulating substrates.
  • the phosphor LED may comprise one or more ceramic substrates.
  • the at least one substrate may be configured for holding the at least one LED die and the at least one luminescent material.
  • the at least one substrate may hold or comprise one or more components of electrical connectivity, such as one or more contact pads and/or one or more electrical leads, such as one or more metallic contacts and/or one or more metallic leads.
  • the substrate such as the ceramic substrate, may be configured to serve as a heat sink. Heat may be generated both in the LED die and in the luminescent material, such as due to a limited conversion of electrical energy into photonic energy, as well as in the luminescent material, e.g. during the conversion process. Said heat may be dissipated in the substrate, such as in ceramic substrate.
  • the spectrometer device using the at least one LED may be configured for applying a continuous wave (CW) mode and/or, preferably, at least one modulation driving scheme, in particular a pulse modulation scheme, for improving precision and reliability of the measurement.
  • the at least one driving unit may be configured for applying a modulation driving scheme to the LED
  • the evaluation device may be configured for taking into account the modulation driving scheme for deriving the at least one spectroscopic information from the at least one detector signal.
  • Lock-In-techniques, filter techniques, and the like may be applied, as known to the skilled person.
  • one or more detector signals may be recorded, e.g. by using a readout electronics, comprised by the spectrometer device, specifically by one or both of the detector and the evaluation device.
  • the readout electronics may comprise one or more signal processing devices.
  • the “raw” detector signal may be used, and/or one or more secondary detector signals derived thereof, such as one or more filtered detector signals.
  • the at least one detector signal, primary or secondary may also be combined with further information, such as information on a wavelength, e.g.
  • the detector signal e.g., a preprocessed detector signal, a processed detector signal, or a combined detector signal.
  • the invention specifically is interesting for correcting the “raw” detector signal, specifically a detector signal, indicating a signal intensity as a function of the detection wavelength.
  • the detector signal e.g.
  • the detector itself and/or by the evaluation unit may be processed or preprocessed into a secondary detector signal, by applying one or more Fourier transformations.
  • a Fast Fourier Transformation may be applied.
  • the at least one spectroscopic information may be derived, such as by a software being executed by the evaluation unit.
  • the Fourier transform of the detector signal may be read out by the software of the spectroscopic device, specifically of the evaluation device, and post-processed into the spectroscopic information on the object.
  • LEDs and phosphor LEDs as outlined above, may, thus, provide for an efficient light source which may be modulated in order to perform specific evaluation schemes and in order to reduce noise and artifacts.
  • the temperatures of the various components of the light source, specifically of the LED may vary over a large temperature range.
  • standard operation currents may range from 2 mA to 1000 mA, typically from 10 mA to 300 mA.
  • forward voltages may be in the range from 1.5 V to 3.5 V, typically from 2.25 V to 3 V.
  • the emitter junction temperature may be 135 °C.
  • the operating case temperature may vary from -40 °C to 135 °C and the emitter storage temperature may vary from -40 °C to 125 °C.
  • the ESD sensitivity of the LED may be 250 V under the standard ANSI/ESDA/JEDEC JS-001-2012. These typical parameters show the large range of temperature variation, which may have an impact on spectroscopic information on the object derived by the spectrometer device. It shall be noted that other parameters and other parameter ranges are feasible, too. It is generally known that, with different compositions of the luminescent material, such as different compositions of phosphors, the phosphor LEDs generate different spectra.
  • each phosphor LED has multiple peaks in the spectrum, wherein the spectrum typically is spread over a wide wavelength range.
  • the spectral properties or the spectrum may change with temperature. These changes may include shifts of the emission peaks, broadening or narrowing of the spectrum, increases or decreases of the emission and the like.
  • the emission at some wavelengths is affected to a larger extent than the emission at other wavelengths.
  • Each wavelength therefore typically has its own temperature coefficient, regarding to the increment/decrement of the power. Therefore, the shape of the spectrum changes with temperature.
  • the evaluation unit may be configured for correcting for the dependence on the temperature of the light source. This may be performed by using the electrically measureable quantity, in particular the forward voltage, as a correction parameter. By using the electrically measureable quantity, in particular the forward voltage, as a correction parameter, an individual temperature correction of the spectrum at the different wavelengths may be performed.
  • the evaluation unit may be configured for individually correcting the detector signals in differing spectral ranges and for combining the individually-corrected detector signals for deriving the spectroscopic information.
  • this individual correction may be performed by using an array of photosensitive elements, wherein each of the photosensitive elements may be configured for generating at least one detector signal and wherein each of the detector signals may individually be corrected by using the electrically measureable quantity, in particular the forward voltage, as a correction parameter.
  • the corrected detector signals may be combined for deriving the spectroscopic information.
  • the electrically measureable quantity, in particular the forward voltage as a correction parameter, temperature changes as well as individual properties of the phosphor LEDs may be corrected for.
  • the forward voltage of the LED typically decreases while temperature increases.
  • Each type of the LED has its own characteristic forward voltage to temperature curve.
  • the forward voltage of the LED linearly decreases with rising temperature, such as with a slope in the range of 1 ⁇ 10 ⁇ to 1 ⁇ 10 ⁇ V/K.
  • the terms “have”, “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situation in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present.
  • the expressions “A has B”, “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e.
  • the terms “preferably”, “more preferably”, “particularly”, “more particularly”, “specifically”, “more specifically” or similar terms are used in conjunction with optional features, without restricting alternative possibilities.
  • features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way.
  • the invention may, as the skilled person will recognize, be performed by using alternative features.
  • features introduced by "in an embodiment of the invention” or similar expressions are intended to be optional features, without any restriction regarding alternative embodiments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.
  • Embodiment 1 A spectrometer device for obtaining spectroscopic information on at least one object, the spectrometer device comprising: i. at least one light source for generating illumination light for illuminating the object, the light source comprising at least one light-emitting diode for generating primary light and at least one luminescent material for light-conversion of the primary light into secondary light; ii. at least one detector for detecting detection light from the object and for generating at least one detector signal; iii.
  • At least one driving unit for driving the light source in a manner that the light-emitting diode is generating the primary light, wherein the light-emitting diode is driven with a pulse modulation scheme having a variable duty cycle for controlling an emission power of the secondary light, wherein the duty cycle is varied based on an influencing parameter having an influence on the light-conversion efficiency of the luminescent material; iv. at least one evaluation unit for evaluating the detector signal generated by the detector and for deriving the spectroscopic information on the object from the detector signal.
  • Embodiment 2 The spectrometer device according to the preceding embodiment, wherein the pulse modulation scheme includes pulsing the light-emitting diode at a driving frequency higher than 1/ ⁇ , preferably at least 5 times, more preferably at least 50 times, even more preferably at least 100 times and yet even more preferably at least 1000 times higher than 1/ ⁇ , wherein ⁇ is a time constant of the light source describing an operating condition of the light source when the driving state of the light source is changed.
  • Embodiment 3 The spectrometer device according to the preceding embodiment, wherein the time constant ⁇ represents a delay that occurs between an absorption of at least one primary photon by the luminescent material and an emission of at least one secondary photon by the luminescent material.
  • Embodiment 4 The spectrometer device according to any one of the two preceding embodiments, wherein the time constant ⁇ is at least one of: - a decay constant ⁇ ⁇ of excited states in the luminescent material; or - a growth constant ⁇ ⁇ of excited states in the luminescent material.
  • Embodiment 5 The spectrometer device according to any one of the three preceding embodiments, wherein the time constant ⁇ depends on a wavelength ⁇ and/or on a temperature ⁇ of the light source, specifically on a temperature ⁇ of the luminescent material.
  • Embodiment 6 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured for causing a driving state of the light source being at least one of: - a first driving state in which the light-emitting diode is generating the primary light; - a second driving state in which the light-emitting diode is not generating primary light.
  • Embodiment 7 The spectrometer device according to the preceding embodiment, wherein the at least one light-emitting diode of the light source is configured for being operated in a pulse mode in a manner that the driving state of the light source changes repeatedly, particularly changes frequently between the first driving state and the second driving state.
  • Embodiment 8 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured to increase the duty cycle in order to compensate a reduction of light-conversion efficiency.
  • Embodiment 9 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured to vary a driving frequency at which the light-emitting diode is pulsed.
  • Embodiment 10 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured to vary a forward current provided to the light-emitting diode and which is required for driving the light source in a manner that the primary light is being generated by the light-emitting diode.
  • Embodiment 11 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured for adjusting at least one of duty cycle, forward current or driving frequency dependent on a temperature of the light source, in particular dependent on a temperature of the luminescent material.
  • Embodiment 12 The spectrometer device according to any one of the preceding embodiments, wherein the emission power of the secondary light is controlled in a manner that the emission power is constant during a measurement with a maximum deviation thereof of 20 %, preferably 10 %, more preferably 5 %, and even more preferably 1 %.
  • Embodiment 13 The spectrometer device according to any one of the preceding embodiments, wherein the driving unit is further configured for driving the light-emitting diode with multiple modulation frequencies at the same time.
  • Embodiment 14 The spectrometer device according to any one of the preceding embodiments, wherein the driving unit is further configured for driving the light-emitting diode with pulse trains and/or chirps, wherein at least one of pulse duration, pulse magnitude or pulse repetition rate is adjusted such that the emission power of the secondary light, which is emitted by the luminescent material of the light source, is stabilized during a measurement.
  • Embodiment 15 The spectrometer device according to any one of the preceding embodiments, wherein the pulse modulation scheme is configured for generating a continuous wave secondary light.
  • Embodiment 16 The spectrometer device according to any one of the preceding embodiments, wherein the light source comprises a phosphor light-emitting diode.
  • Embodiment 17 The spectrometer device according to any one of the preceding embodiments, wherein the light-emitting diode has a primary emission range at least partially located in the spectral range of 420 nm to 460 nm, more specifically in the range of 440 nm to 455 nm, more specifically at 440 nm.
  • Embodiment 18 The spectrometer device according to any one of the preceding embodiments, wherein the illumination light has a spectral range at least partially located in the near- infrared spectral range, specifically in the spectral range from 1 to 3 ⁇ m, preferably from 1.3 to 2.5 ⁇ m, more preferably from 1.5 to 2.2 ⁇ m.
  • Embodiment 19 The spectrometer device according to any one of the preceding embodiments, wherein the detector comprises a plurality of photosensitive elements, wherein each of the photosensitive elements is configured for generating at least one detector signal dependent on an illumination of its light-sensitive region, wherein the evaluation unit is configured for individually correcting each of the detector signals and for combining the detector signals for deriving the spectroscopic information.
  • Embodiment 20 The spectrometer device according to the preceding embodiment, wherein the spectrometer device is configured such that the photosensitive elements are sensitive to differing spectral ranges of the detection light from one or more of the object at least one internal target, or radiation coming from the light source and directed to the detector without any reflection.
  • Embodiment 21 The spectrometer device according to any one of the preceding embodiments, wherein the spectrometer device comprises at least one wavelength-selective element disposed in a beam path of the detection light, wherein the wavelength-selective element is configured such that each of the photosensitive elements is exposed to an individual spectral range of the detection light.
  • Embodiment 22 The spectrometer device according to the preceding embodiment, wherein the wavelength-selective element is selected from the group of a tunable wavelength- selective element and a wavelength-selective element having a fixed transmission spectrum.
  • Embodiment 23 A method of obtaining spectroscopic information on at least one object, the method comprising: a.
  • the light source comprising at least one light-emitting diode for generating primary light and at least one luminescent material for light-conversion of the primary light into secondary light
  • the driving unit is configured for driving the light source in a manner that the light-emitting diode is generating the primary light, wherein the light-emitting diode is driven with a pulse modulation scheme having a variable duty cycle for controlling an emission power of the secondary light, wherein the duty cycle is varied based on an influencing parameter having an influence on the light- conversion efficiency of the luminescent material;
  • Embodiment 24 The method according to the preceding embodiment, wherein a spectrometer device according to any one of the preceding embodiments referring to a spectrometer device is used.
  • Embodiment 25 The method according to any one of the preceding method embodiments, wherein the method is performed on-line in the field.
  • Embodiment 26 The method according to anyone of the preceding method embodiments, wherein the method is computer-implemented.
  • Embodiment 27 A computer program comprising instructions which, when the program is executed by the spectrometer device according to any one of the preceding embodiments referring to a spectrometer device, cause the spectrometer device to perform the method according to any one of the preceding embodiments referring to a method.
  • Embodiment 28 A computer-readable storage medium comprising instructions which, when the instructions are executed by the spectrometer device according to any one of the preceding embodiments referring to a spectrometer device, cause the spectrometer device to perform the method according to any one of the preceding embodiments referring to a method.
  • Embodiment 29 A non-transient computer-readable medium including instructions that, when executed by one or more processors, cause the one or more processors to perform the method according to any one of the preceding embodiments referring to a method.
  • Short description of the Figures Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restricted by the preferred embodiments.
  • the embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally comparable elements.
  • Figure 1 shows a schematic overview of a spectrometer device
  • Figure 2 shows schematic cross-sectional view of a light source
  • Figure 3 shows a schematic flowchart illustrating generating and processing a detector signal
  • Figure 4 shows a diagram representing a superposition of spectra of infrared radiation of a phosphor LED at various temperatures
  • Figure 5 shows a diagram representing a change in emission power change as a function of temperature for a selected number of wavelengths
  • Figure 6 shows a diagram of a forward voltage as a function of temperature for a selected current
  • Figures 7A and 7B show spectra of two different types of phosphor LEDs
  • Figures 8A and 8B show diagrams representing decay constants (Figure 8A) and growth constants (Figure 8B) as a function of wavelength for a phosphor LED emitting between 1.3 ⁇ m and 2 ⁇ m
  • Figure 9A and 9B show diagrams representing decay constants (Figure 9A) and growth constants (Figure 9B) as a function of wavelength for
  • the spectrometer device 110 may comprise a plurality of components as illustrated in Figure 1. Possible components of the spectrometer device 110 and their interplay will be described in the following, specifically with reference to Figure 1.
  • the spectrometer device 110 comprises at least one light source 114 for generating illumination light 116 for illuminating the object 112.
  • the light source 114 may be at least one of a tunable light source, a light source having at least one fixed emission wavelength and a broadband light source.
  • the light source 114 specifically may be or may comprise at least one electrical light source.
  • the light source 114 comprises at least one light-emitting diode 118 and at least one luminescent material 120 for light-conversion of primary light generated by the light- emitting diode 118.
  • the light-emitting diode 118 may comprise one or more of: a light-emitting diode (LED) based on spontaneous emission of light, a light-emitting diode based on superluminescence (sLED), a laser diode (LLED).
  • the LED 118 may specifically comprise at least two layers of semiconductor material 121, wherein light may be generated at at least one interface between the at least two layers of semiconductor material 121, specifically due to a recombination of positive and negative electrical charges.
  • the at least two layers of semiconductor material 121 may have differing electrical properties, such as at least one of the layers being an n-doped semiconductor material 121 and at least one of the layers being a p-doped semiconductor material 121.
  • the LED 118 may comprise at least one pn-junction and/or at least one pin-set up. It shall be noted, however, that other device structures are feasible, too.
  • the light-emitting diode 118 may generate primary light, which may also be referred to as “pump light”. The primary light may subsequently be transformed into “secondary light”, such as by using light conversion, e.g. through one or more luminescent materials 120, such as phosphor materials.
  • the at least one luminescent material 120 may form at least one converter, also referred to as a light converter, transforming primary light into secondary light having different spectral properties as compared to the primary light.
  • a spectral width of the secondary light may be larger than a spectral width of the primary light, and/or a center of emission of the secondary light may be shifted, specifically red-shifted, compared to the primary light.
  • the at least one luminescent material 120 may have an absorption in the ultraviolet and/or blue spectral range and an emission in the near-infrared and/or infrared spectral range.
  • the illumination light 116 may be or may comprise at least one of the primary light or a part thereof, the secondary light or a part thereof, or a mixture of both.
  • the light source 114 may specifically comprise a phosphor light- emitting diode 122, also referred to as phosphor LED 122.
  • the phosphor LED 122 may be a combination of at least one light-emitting diode 118 configured for generating primary light or pump light, and at least one luminescent material 120, also referred to as a “phosphor”, configured for light-conversion of the primary light generated by the light-emitting diode 118.
  • the phosphor LED 122 may form a packaged LED light source, including an LED die 124, e.g.
  • FIG. 2 shows a more detailed view of the light source 114 embodied as a phosphor LED 122.
  • the light source 114 can be embodied in various ways.
  • the light source 114 can, for example, be part of the spectrometer device 110 in a housing 126 of the spectrometer device 110, as illustrated in Figure 1.
  • the at least one light source 114 can also be arranged outside the housing 126, for example as a separate light source 114 (not shown).
  • the light source 114 can be arranged separately from the object 112 and illuminate the object 112 from a distance, as indicated in Figure 1.
  • Illumination light 116 as generated by the light source 114 may propagate from the light source 114 to the object 112.
  • the illumination light 116 generated by the light source 114 and propagating to the object 112 is illustrated by an arrow.
  • the object 112 specifically may comprise at least one sample, which may fully or partially be analyzed by spectroscopic methods.
  • the spectrometer device 110 further comprises at least one detector 128 configured for detecting detection light 130 from the object 112.
  • illumination light 116 While light propagating from the light source 114 to the object 112 may be referred to as illumination light 116, light propagating from the object 112 to the detector 128 may be denoted as “detection light” 130.
  • detection light 130 is illustrated by an arrow.
  • the detection light 130 may comprise at least one of illumination light 116 reflected by the object 112, illumination light 116 scattered by the object 112, illumination light 116 transmitted by the object 112, luminescence light generated by the object 112, e.g. phosphorescence or fluorescence light generated by the object 112 after optical, electrical or acoustic excitation of the object 112 by the illumination light 116 or the like.
  • the detection light 130 may directly or indirectly be generated through the illumination of the object 112 by the illumination light 116.
  • the detector 128 may be or may comprise at least one optical detector 132.
  • the optical detector 132 may be configured for determining at least one optical parameter, such as an intensity and/or a power of light by which at least one sensitive area of the optical detector 132 is irradiated. More specifically, the optical detector 132 may comprise at least one photosensitive element and/or at least one optical sensor, such as at least one of a photodiode, a photocell, a photosensitive resistor, a phototransistor, a thermophile sensor, a photoacoustic sensor, a pyroelectric sensor, a photomultiplier and a bolometer.
  • the detector 128, thus, may be configured for generating at least one electrical detector signal in the above-mentioned sense, providing information on at least one optical parameter, such as the power and/or intensity of light by which the detector 128 or a sensitive area of the detector 128 is illuminated.
  • the detector 128 may comprise one single optically sensitive element or area or a plurality of optically sensitive elements or areas.
  • the detector 128 may comprise at least one detector array, more specifically an array of photosensitive elements 134. Each of the photosensitive elements 134 may be configured for generating at least one detector signal.
  • each of the photosensitive elements 134 may comprise at least a photosensitive area, which may be adapted for generating an electrical signal depending on the intensity of the incident light, wherein the electrical signal may, in particular, be provided to an evaluation unit 136 of the spectrometer device 110, as will be outlined in further detail below.
  • the detector 128 comprises the array of optically sensitive elements 134
  • the detector 128, may e.g. be selected from any known pixel sensor, specifically from a CCD chip or a CMOS chip.
  • the detector 128 generally may be or comprise a photoconductor, in particular an inorganic photoconductor, especially PbS, PbSe, Ge, InGaAs, ext.
  • the spectrometer device 110 comprises at least one evaluation unit 136 configured for evaluating the detector signal S ⁇ and for deriving the spectroscopic information on the object 112 from the detector signal S ⁇ . Further, the evaluation unit 136 is configured for correcting for a temperature dependent drift of the detector 128 in the detector signal S ⁇ by using the reference detector signal R.
  • the detector 128 may directly or indirectly provide the detector signals to the evaluation unit 136. Thus, the detector 128 and the evaluation unit 136 may be directly or indirectly connected, as indicated by arrows in Figure 1.
  • the detector signal may be used as a “raw” detector signal and/or may be processed or preprocessed before further use, e.g. by filtering and the like.
  • the detector 128 may comprise at least one processing device and/or at least one preprocessing device, such as at least one of an amplifier, an analogue/digital converter, an electrical filter and a Fourier transformation.
  • the correcting may comprise determining a ratio of the detector signal S ⁇ and the reference detector signal R. This may allow correcting, in particular eliminating, the temperature of the detector 128 from the temperature dependence of the detector signal.
  • the corrected temperature signal may depend on the temperature of the light source 114 but not on the temperature of the detector 128.
  • the evaluation unit 136 specifically may be configured, e.g. by software programming, for correcting the detector signal for a temperature dependent drift of the detector 128.
  • the evaluation unit 136 may be configured for correcting for the dependence on the temperature of the light source 114 by using at least one correction and/or calibration algorithm, in addition, as will be outlined in further detail below.
  • the spectrometer device 110 may further comprise at least one driving unit 138 for electrically driving the light source 114.
  • the spectrometer device 110 may comprise at least one measurement unit 139.
  • the measurement unit 139 may be configured for generating at least one item of information on at least one electrically measurable quantity, in particular a forward voltage, required for driving the light-emitting diode 118.
  • the measurement unit 139 may be an element of the driving unit 138, as indicated in Figure 1.
  • the driving unit 138 may be configured for providing an electrical current to the LED 118, specifically for controlling an electrical current through the LED 118.
  • the driving unit 138 may be configured for adapting and measuring a voltage provided to the LED 118, the voltage being required for achieving a specific electrical current through the LED 118.
  • the driving unit 138 may comprise one or more of: a current source 140, a voltage source, a current measurement device, such as an Ampère-meter, a voltage measurement device 142, such as a Volt-meter, a power measurement device.
  • the driving unit 138 may comprise at least one current source 140 for providing at least one predetermined current to the LED 118, wherein the current source 140 specifically may be configured for adjusting or controlling a voltage applied to the LED 118 in order to generate the predetermined current.
  • the driving unit 138 may comprise one or more electrical components, such as integrated circuits, for driving the light source 114.
  • the driving unit 138 may be fully or partially integrated into the light source 114 or may be separated from the light source 114, the latter configuration being illustrated in Figure 1. As outlined above, the driving unit 138 may be configured for generating at least one item of information on at least one electrically measurable quantity, in particular a forward voltage, required for driving the light-emitting diode 118.
  • the forward voltage may be applied to the LED 118 in the forward direction, i.e. as with a positive contact of a voltage or current source 140 applied to a p-layer of the LED 118 and a negative contact applied to the n-layer of the LED 118, in order to generate a predetermined electrical current through the LED 118.
  • the predetermined current defining the forward voltage may be a current, which is known to generate a predetermined light output of the light source 114 and/or of the light- emitting diode 118.
  • the measurement unit 139 may comprise one or more measurement devices or measurement elements, such as one or more voltage measurement devices 142.
  • the at least one item of information on the at least one electrically measurable quantity, in particular the forward voltage may be provided by the measurement unit 139 in the form of at least one electrical signal and/or electrical information, e.g., comprising one or both of an analogue signal and a digital signal.
  • the electrical signal comprising the at least one item of information on the at least one electrically measurable quantity, in particular the forward voltage may directly or indirectly be provided to the evaluation unit 136.
  • the electrical signal may be time-dependent or static.
  • the spectrometer device 110 comprises the at least one evaluation unit 136 for evaluating the detector signal S ⁇ 128 and for deriving the spectroscopic information on the object 112 from the detector signal S ⁇ .
  • the evaluation unit 136 may be configured for taking into consideration the item of information on the at least one electrically measurable quantity, in particular the forward voltage, when deriving the spectroscopic information from the detector signal S ⁇ .
  • the evaluation unit 136 may be configured for processing at least one input signal and to generate at least one output signal thereof.
  • the at least one input signal may comprise the detector signal S ⁇ and the reference detector signal R provided directly or indirectly by the at least one detector 128 and, additionally, at least one signal directly or indirectly provided by the measurement unit 139, the signal comprising the at least one item of information on the at least one electrically measurable quantity, in particular the forward voltage.
  • the arrows between the driving unit 138, which comprises the measurement unit 139 in the embodiment illustrated in Figure 1, and the evaluation unit 136 in Figure 1 illustrate the process of providing to the evaluation unit 136 and/or retrieving by the evaluation unit 136 the signal comprising the at least one item of information on the at least one electrically measurable quantity, in particular the forward voltage.
  • the evaluation unit 136 may be or may comprise one or more integrated circuits, such as one or more application-specific integrated circuits (ASICs), and/or one or more data processing devices 144, such as one or more of computers, digital signal processors (DSP), field programmable gate arrays (FPGA), preferably one or more microcomputers and/or microcontrollers.
  • ASICs application-specific integrated circuits
  • DSP digital signal processors
  • FPGA field programmable gate arrays
  • Additional components may be comprised, such as one or more preprocessing devices 146 and/or data acquisition devices, such as one or more devices for receiving and/or preprocessing of the detector signals, such as one or more AD-converters and/or one or more filters.
  • the evaluation unit 136 may comprise one or more data storage devices 148, as shown in Figure 1.
  • the evaluation unit 136 may comprise one or more interfaces, such as one or more wireless interfaces and/or one or more wire-bound interfaces.
  • the evaluation unit 136 may be configured, e.g.
  • the evaluation unit 136 further may be configured for correcting the at least one detector signal S ⁇ , specifically the corrected detector signal S ⁇ ,corr , for the dependence on the temperature of the light source 114 by using the additional correction from the item of information on the at least one electrically measurable quantity, in particular the forward voltage.
  • the additional correction specifically may comprise multiplying the detector signal S ⁇ , specifically the corrected detector signal S ⁇ ,corr, with at least one correction factor as described in detail above and as will be described further below in an exemplary fashion.
  • the evaluation unit 136 specifically may be configured for using the corrected detector signal for deriving the spectroscopic information.
  • the detector 128 may specifically comprise an array of photosensitive elements 134. Each of the photosensitive elements may be configured for generating at least one detector signal.
  • the evaluation unit 136 may be configured for individually correcting each of the detector signals and/or for combining the detector signals for deriving the spectroscopic information.
  • the spectrometer device 110 may be configured such that the photosensitive elements of the detector 128 are sensitive to differing spectral ranges of the light from the object 112.
  • the detector 128 may be configured for generating detector signals for at least two differing spectral ranges of the light from the object 112, specifically at least one of sequentially and simultaneously.
  • the spectrometer 110 specifically may comprise at least one filter element 150 disposed in a beam path of the light from the object 112.
  • the filter element 150 specifically may be configured such that each of the photosensitive elements is exposed to an individual spectral range of the light from the object 112.
  • the spectrometer device 110 further may comprise one or more optical components 151, e.g.
  • the one or more optical components 151 may be arranged in at least one of the beam path of the illumination light 116 and the beam path of the detection light 130.
  • the spectrometer device 110 may in particular comprise the at least one wavelength-selective element 152.
  • the wavelength-selective element 152 specifically may be selected from the group of a tunable wavelength-selective element 152 and a wavelength-selective element 152 having a fixed transmission spectrum.
  • differing wavelength ranges may be selected sequentially, whereas, by using a wavelength-selective element 152 having a fixed transmission spectrum, the selection of the wavelength ranges may be fixed and may, however, be dependent e.g. on a detector position.
  • the wavelength-selective element 152 may be used for separating incident light into a spectrum of constituent wavelength signals whose respective intensities are determined by employing a detector, e.g. the detector 128 of the spectrometer device 110, which may comprise the array of photosensitive elements 134.
  • the at least one wavelength-selective element 152 may e.g. comprise at least one of a filter, a grating and a prism.
  • the wavelength-selective element 152 may specifically comprise at least one of a wavelength-selective element 152 disposed in the beam path of the illumination light 116 and a wavelength-selective element 152 disposed in the beam path of the detection light 130.
  • Figure 1 illustrates an embodiment of the spectrometer device 110 with one wavelength-selective element 152 arranged in the beam path of the illumination light 116, and one wavelength- selective element 152 arranged in the beam path of the detection light 130.
  • the spectrometer device 110 as represented in a schematic fashion in Figure 1 is configured for obtaining spectroscopic information on the at least one object 112.
  • the spectrometer device 110 may be configured for obtaining an item of information, e.g.
  • the at least one item of spectral information may comprise at least one intensity information, e.g. information on an intensity of light being at least one of transmitted, absorbed, reflected or emitted by the object 112, e.g. as a function of a wavelength or wavelength sub-range over one or more wavelengths, e.g. over a range of wavelengths.
  • the spectrometer device 110 may be configured for acquiring at least one spectrum or at least a part of a spectrum of detection light 130 propagating from the object 112 to the detector 128.
  • the spectrum may describe the radiometric unit of spectral flux, e.g. given in units of watt per nanometer (W / nm), or other units, e.g. as a function of the wavelength of the detection light 130.
  • the spectrum may describe the optical power of light, e.g. in the NIR spectral range, in a specific wavelength band.
  • the spectrum may contain one or more optical variables as a function of the wavelength, e.g. the power spectral density, electric signals derived by optical measurements and the like. Examples of spectra are shown e.g.
  • the spectrometer device 110 may specifically be a portable spectrometer device 110, which may in particular be used in the field.
  • a schematic cross-sectional view of a light source 114 is shown.
  • the at least one light source 114 of the spectrometer device 110 may be configured for generating or providing to electromagnetic radiation in one or more of the infrared, the visible and the ultraviolet spectral range.
  • light used for the typical purposes of the present invention is light in the infrared (IR) spectral range, more preferred, in the near infrared (NIR) and/or the mid infrared spectral range (MidIR), especially the light having a wavelength of 1 ⁇ m to 5 ⁇ m, preferably of 1 ⁇ m to 3 ⁇ m.
  • the light source 114 comprises the at least one light-emitting diode 118 and the at least one luminescent material 120 for light-conversion of primary light generated by the light-emitting diode 118.
  • the LED 118 and the luminescent material 120 may form the phosphor LED 122, as described above.
  • the phosphor LED 122 as illustrated in Figure 2 may comprise one or more functional components.
  • the phosphor LED 122 may comprise one or more substrates 154, specifically one or more electrically insulating substrates 154.
  • the phosphor LED 122 may comprise one or more ceramic substrates 156, as shown in Figure 2.
  • the substrate 154 may be configured for holding the at least one LED die 124 and the at least one luminescent material 120.
  • the at least one substrate 154 may hold or comprise one or more components of electrical connectivity, such as one or more contact pads 158 as shown in Figure 2 and/or one or more electrical leads, such as one or more metallic contacts and/or one or more metallic leads.
  • the substrate 154 may be configured to serve as a heat sink. Heat may be generated in the LED die 124, such as due to a limited conversion of electrical energy into photonic energy, as well as in the luminescent material 120, e.g. during the conversion process. Said heat may be dissipated in the substrate 154, such as in ceramic substrate. As shown in Figure 2, the phosphor LED 122 may comprise the light-emitting diode 118.
  • the light-emitting diode 118 may be configured for converting electrical current into primary light, such as blue primary light, using at least one LED chip and/or the at least one LED die 124 as illustrated in Figure 2.
  • p-n-diodes may be used.
  • one or more LEDs 118 selected from the group of an LED 118 on the basis of indium gallium nitride (InGaN), an LED 118 on the basis of GaN, an LED 118 on the basis of InGaN/GaN alloys or combinations thereof and/or other LEDs 118 may be used.
  • quantum well LEDs 118 may also be used, such as one or more quantum well LEDs 118 on the basis of InGaN.
  • the phosphor LED 122 may comprise the at least one luminescent material 120 configured for light-conversion of the primary light generated by the light-emitting diode 118.
  • the luminescent material 120 may comprise at least one of: Cerium-doped YAG (YAG:Ce3 + , or Y 3 Al 5 O 12 :Ce 3+ ); rare- earth-doped Sialons; copper- and aluminum-doped zinc sulfide (ZnS:Cu,Al).
  • the luminescent material 120 specifically may form at least one layer.
  • the luminescent material 120 e.g. at least one layer of the luminescent material 120, such as the phosphor, may be positioned directly on the light-emitting diode 118, e.g. with no material in between the LED 118 and the luminescent material 120 or with one or more transparent materials in between, such as with one or more transparent materials, specifically transparent for the primary light, in between the LED 118 and the luminescent material 120.
  • a coating of the luminescent material 120 may be placed directly or indirectly on the LED 118 (not shown).
  • the luminescent material 120 may form at least one converter body 160, such as at least one converter disk, which may also be referred to as converter platelet.
  • the converter body 160 may be placed on top of the LED 118, e.g. by adhesive attachment of the converter body 160 to the LED 118, as illustrated in Figure 2.
  • the luminescent material 120 may also be placed in a remote fashion, such that the primary light from the LED 118 has to pass an intermediate optical path before reaching the luminescent material 120 (not shown).
  • the luminescent material 120 in the remote placement may form a solid body or converter body 160, such as a disk or converter disk.
  • one or more optical elements may be placed, such as one or more of a lens, a prism, a grating, a mirror, an aperture or a combination thereof.
  • an optical system having imaging properties may be placed in between the LED 118 and the luminescent material 120, in the intermediate optical path.
  • the primary light may be focused, or bundled onto the converter body 160.
  • the at least one luminescent material 120 may be located with respect to the light-emitting diode 118 such that a heat transfer from the light-emitting diode 118 to the luminescent material 120 is possible.
  • the luminescent material 120 may be located such that a heat transfer by one or both of thermal radiation and heat conduction is possible, more preferably by heat conduction.
  • the luminescent material 120 may be in thermal contact and/or in physical contact with the light-emitting diode 118 as illustrated in Figure 2. Thereby, generally, a temperature of the luminescent material 120 and a temperature of the light-emitting diode 118 may be coupled.
  • the light source 114 may comprise further components such as at least one side coat 162 covering at least one side, such as a top side, a bottom side and/or one or more lateral sides of at least of: the substrate 154, the contact pad 158, the light-emitting diode 118 and the luminescent material 120.
  • the side coat 162 may cover gaps and/or interspaces that may be present in the layered set-up of the light source 114 as shown in Figure 2. Further components of the light source 114, specifically components, which are not shown in Figure 2, are feasible.
  • the light source 114 in particular the phosphor LED 122, may be packaged in one housing (not shown in Figure 2) or may be unpackaged.
  • the LED 118 and the at least one luminescent material 120 for light- conversion of the primary light generated by the light-emitting diode 118 may specifically be housed in a common housing.
  • the LED 118 may also be an unhoused or bare LED 118, as illustrated in Figure 2.
  • the schematic flowchart of Figure 3 illustrates the process of generating the detector signal as well as processing of the detector signal, e.g. to generate a corrected signal.
  • hardware components 164 which may take part in the process or generating and/or preprocessing the detector signal as well as software components 166, which may take part in processing and/or correcting the detector signal, are illustrated in Figure 3.
  • the hardware components 164 also simply referred to as “hardware” 164, may specifically comprise the at least one light-emitting diode 118 of the spectrometer device 110, in particular a blue LED 118, configured for emitting blue primary light.
  • the hardware components 164 may further comprise the luminescent material 120, also referred to as LED phosphor, the object 112 as well as one or more optical components 151, e.g. the at least one wavelength-selective element 152, and the detector 128.
  • a correction for temperature changes may be performed, even for local temperature changes within the light source 114, which may have an impact on the emission characteristics of the light source 114.
  • temperatures for selected hardware components 164 are indicated in Figure 3.
  • the hardware components 164 may have differing or identical temperatures, e.g. depending on an arrangement of the hardware components 164, such as their relative positions and distances in the spectrometer device 110.
  • the temperature of the luminescent material 120 and the temperature of the light- emitting diode 118 may be coupled, e.g.
  • the temperature of the LED 118 which may also be referred to as “Tpn”, and the temperature of the luminescent material 120, which may also be referred to as “T Ph ”, may be similar or even identical.
  • the temperature of the LED 118 is indicated with reference sign 168
  • the temperature of the luminescent material 120 is indicated with reference sign 170
  • the LED 118 may emit primary light when an electrical current flows through the LED 118, e.g.
  • a target signal S t may be provided as indicated in Figure 3 by reference sign 174, e.g. to the driving unit 138, to drive the LED 118 to emit blue primary light.
  • the target signal St 174 may in particular be a predetermined current value that is to be generated through the LED 118, e.g. by applying an appropriate voltage.
  • the predetermined current value may in particular be in the range from 10 mA to 500 mA, more specifically in the range from 100 mA to 300 mA, e.g. a current value of 50 mA.
  • the predetermined current may be known to generate a predetermined light output of the LED 118, such as blue primary light.
  • the LED 118 may be at the temperature “T pn ” indicated by reference sign 168.
  • the blue primary light may be converted by the luminescent material 120 into secondary light, such as into light in the infrared spectral range.
  • the luminescent material 120 may be at the temperature “T ph ” indicated by reference sign 170.
  • the illumination light 116 generated by the light source 114 which may comprise at least one of the primary light or a part thereof, the secondary light or a part thereof, or a mixture of both, may illuminate the object 112.
  • one or more optical components 151 such as one or more mirrors, lenses, wavelength selective elements 152 or other optical components 151 may be used, e.g. by placing the optical components 151 in the beam path of the illumination light 116.
  • the detection light from the object 112, e.g. reflected light, may be directed to the detector 128.
  • one or more optical components 151 may be used.
  • one or more wavelength-selective elements 152 may be used, such as one or more dispersive elements, e.g. for splitting the detection light 130 into its spectral components.
  • the detector 128 may e.g. comprise an array of photosensitive elements 134.
  • the detector 128 may be or may comprise a pixel sensor, such as a CCD chip or a CMOS chip, comprising a plurality of pixels arranged on the chip.
  • each of the pixels may correspond to a predetermined spectral range, e.g. by being sensitive to the predetermined spectral range.
  • the detector 128 may thus generate the detector signal S ⁇ , in the following denoted as “Spx,i”, as indicated in Figure 3 by reference sign 176, comprising a plurality of detector signals, and the reference detector signal R.
  • Each of the plurality of detector signals may correspond to an electronic signal generated by one of the plurality of pixels of the detector 128.
  • Each of the plurality of detector signals may e.g.
  • the detector signal S px,i 176 may specifically be a function of the wavelength of the detection light 130, as indicated by the index “px”.
  • the signal Spx,i 176 may further be a function of time, e.g. in the case of time-dependent detector signals, as indicated by the index “i”.
  • the plurality of signals comprised by the detector signal S px,i 176 may be generated simultaneously or in a temporally successive manner.
  • the detector signal Spx,i 176 may be determined using readout electronics 178 as indicated in Figure 3.
  • the detector signal S px,i 176 may be processed, e.g.
  • the pixels comprised by the detector 128 may specifically be active pixel sensors, which may be adapted to amplify the electronic detector signal S px,i 176, e.g. as part of a preprocessing process prior to further processing that may e.g. be performed by one or more of the software components 166.
  • the signal S px,i 176 as generated by the detector 128 may also be referred to as “Frame signal S px,i 176”.
  • Figure 3 illustrates the process of providing the signal S px,i 176 to one of the software components 166 with an arrow.
  • the software components 166 configured for processing and/or correcting the detector signal S px,i , 176 may comprise at least one first software 180, which may also be referred to as “software 1”, and at least one second software 182, which may also be referred to as “software 2”.
  • the first software 180 may be configured for performing at least one first processing step 184, also referred to as “processing 1”, on the detector signal S px,i 176, such as by applying at least one algorithm to the detector signal S px,i 176.
  • the first processing step 184 may comprise at least one correction of transient or time-dependent effects.
  • the first processing step 184 may comprise one or more of the following: a correction for the temperature dependent drift of the detector 128; a correction of the dark signal; a correction of dark signal drift; a correction of fluctuation effects; a correction of photodetector response for individual detector elements or individual time steps; a correction of environment-induced, e.g., temperature-induced changes of the photodetector response; an extraction of information for subsequent processing; an addition or multiplication with a parameter, which was generated from information on the at least one electrically measurable quantity, in particular the forward voltage, or on device temperature.
  • the first software 180 may be configured for performing at least one further step comprising at least one fast Fourier transform 186 to the detector signal.
  • a signal S px 188 also referred to as “pixel signal S px 188”
  • pixel signal S px 188 may be generated, which may no longer be a function of time.
  • the time dependency of the frame signal Spx,i 176 may be eliminated by one or more of the steps forming part of the first software component 1 while the wavelength dependency may still be present in the on signal S px 188 as indicated by the index “pn”.
  • Figure 3 further illustrates the process of providing the signal Spx 188 to the second software 182 with an arrow.
  • the second software 182 may be configured for performing at least one second processing step 190, also referred to as “processing 2”, on the signal S px 188, such as by applying at least one algorithm to the signal S px 188, thereby generating at least one corrected signal Spx, corr 191.
  • the second processing step 190 may comprise one or more of the following: a correction for the temperature dependent drift of the detector 128; a correction of the dark signal; a correction of dark signal drift; a correction of fluctuation effects; a correction of photodetector response for individual detector elements or individual time steps; a correction of environment-induced, e.g., temperature-induced changes of the photodetector response; an extraction of information for subsequent processing; a manipulation with at least one parameter, for example an addition or multiplication with a parameter, which was generated from information on the at least one electrically measurable quantity, in particular the forward voltage, or on device temperature.
  • the corrected signal S px, corr 191 may comprise a plurality of corrected signals, such as a plurality of corrected electronic signals. Each of the plurality of corrected signals may specifically correspond to a corrected number of counts of the respective pixel.
  • the spectrometer device 110 comprises the evaluation unit 136 for evaluating the detector signal S ⁇ and for deriving the spectroscopic information on the object 112 from the detector signal S ⁇ .
  • the evaluation unit 136 is configured for correcting for a temperature dependent drift of the detector 128 in the detector signal S ⁇ by using the reference detector signal R.
  • the correction for the temperature dependent drift of the detector 128 may specifically be applied to the time-resolved signal S px,i 176 and/or to the time-independent value S px 188. Additionally, the evaluation unit 136 may take into consideration the item of information on the at least one electrically measurable quantity, in particular the forward voltage, when deriving the spectroscopic information from the detector signal S ⁇ , specifically from the corrected detector signal S ⁇ ,corr . The evaluation unit 136 may in particular be configured by software programming for evaluating and/or processing the detector signal S ⁇ and the reference detector signal R as part of the first processing step 184 of the at least one first software 180.
  • the evaluation unit 136 may further be configured for determining the additional correction from the item of information on the at least one electrically measurable quantity, in particular the forward voltage, and may further be configured for correcting the at least one detector signal S ⁇ , specifically the corrected detector signal S ⁇ ,corr , by using the additional correction.
  • Both the light-emitting diode 118 and the luminescent material 120 may be based on different materials and/or different compositions of materials, e.g. as described in more detail above, which, generally, may affect and influence the spectrum 192 of the phosphor LED 122. However, the spectrum 192 or the spectral properties of a specific phosphor LED 122 may change with temperature, even when being operated at a specific, predetermined current.
  • the temperature of the phosphor LED 122 generating the illumination light 116 ranges from 25°C to 50°C.
  • a specific central wavelength where the power spectral density typically does not change with temperature.
  • Each wavelength therefore typically has its own temperature coefficient, regarding to the increment/decrement of the power. Therefore, the shape of the spectrum 192 changes with temperature as apparent from Figure 4.
  • a number of four specific wavelength intervals each centering around one of four specific wavelengths ranging across the spectrum 192 are indicated in Figure 4. The wavelength intervals are delimited by dashed lines.
  • the emission power change normalized to the emission power change at 25°C is shown in the diagram in Figure 5 as a function of temperature over a temperature range from 25°C to 50°C.
  • the emission power change normalized to the emission power change at 25°C given in percent is shown on the y-axis 196 and represented by reference sign 219, while the temperature in °C, represented by reference sign 220, is indicated on the x-axis 200.
  • the lines in the diagram in Figure 5 indicate fitted curves 236.
  • the emission power at the central wavelength of 1802 nm may change very little over the observed temperature range (that is, the emission power change is zero or close to zero), while the emission power change may change considerably for other wavelengths, e.g. for 1643 nm or 1953 nm.
  • the central wavelength of 1802 nm (denoted by reference number 206 in Figures 4 and 5) may be used as the predetermined calibration wavelength range at which the light source 114 exhibits a minimum emission power change with temperature in order to generate the reference detector signal.
  • the appropriate forward voltage may be a function of the temperature of the light- emitting diode 118.
  • the forward voltage of the LED 118 typically decreases while temperature increases.
  • Each type of the LED 118 has its own characteristic forward voltage to temperature curve.
  • the forward voltage of the LED 118 linearly decreases with rising temperature, such as with a slope in the range of 1 ⁇ 10 ⁇ to 1 ⁇ 10 ⁇ V/K.
  • Figure 6 illustrates this relationship for a specific LED 118.
  • the diagram of Figure 6 shows the forward voltage applied to an LED 118 for the generation of a direct current of 150 mA through the LED 118 as a function of the temperature of the LED 118.
  • the forward voltage in the units of Volt is represented by reference sign 224 on the y-axis 196.
  • the temperature in °C is indicated by reference sign 220 on the x- axis 200.
  • the forward voltage in this case, decreases linearly with increasing temperature.
  • measuring points 221 represented by grey, filled circles are shown as well as a dashed line corresponding to the above given fitted curve 235.
  • a relation between another electrically measurable quantity required for driving the light source 114 and the temperature may be used, e.g. a fed in electrical power; a current, resistance, inductance, capacitance and the like.
  • an electrically measurable quantity, in particular the forward voltage, as a correction parameter an individual temperature correction of the spectrum 192 at the different wavelengths may be performed.
  • the evaluation unit 136 may be configured for individually correcting the plurality of detector signals of the detector signal S px,i and for combining the individually-corrected detector signals for deriving the spectroscopic information.
  • the individual correction may be performed by using the array of photosensitive elements 134, wherein each of the photosensitive elements may be configured for generating at least one detector signal and wherein each of the detector signals may individually be corrected by using the at least one electrically measurable quantity, in particular the forward voltage, as a correction parameter.
  • the corrected detector signals may be combined for deriving the spectroscopic information.
  • the spectrometer device 110 may specifically take into account the characteristics of the luminescent material 120 used in the light source 114.
  • the luminescent material 120 may be configured for absorbing primary photons generated by the light-emitting diode 118 and may, as a reaction, emit secondary photons instantaneously or after a delay or decay time.
  • the signal or emission of the phosphor LED 122 after turning off the forward current may be described using equations (1) and (2) as described above.
  • characteristic for the luminescent material 120 may in particular be the decay constant ⁇ ⁇ 228, which may describe the typical time of an afterglow of the luminescent material 120, as well as the growth constant ⁇ ⁇ , which may describe the typical time for reaching a saturation of the emission of converted light.
  • the time constants ⁇ ⁇ and ⁇ ⁇ typically differ between different phosphor LEDs 122 and/or between different types of the luminescent material 120.
  • decay constant ⁇ ⁇ and growth constant ⁇ ⁇ may depend on the wavelength.
  • the time constants typically are extracted from step response of the optical signal by applying / shutting off the forward current.
  • Figures 7A and 7B show spectra 192 of two different types of phosphor LEDs 122, which emit light in the near infrared range. Specifically the power spectral density is shown as a function of the wavelength, which is given in nm. As apparent from Figures 7A and 7B the spectra 192 of the two different phosphor LEDs 122 differ. Thus, as an example, the spectrum 192 shown in Figure 7A reflects a high emission in the range from 1400 nm to 1600 nm, while the emission in this region is negligible for the phosphor LED 122, whose spectrum 192 is shown in Figure 7B.
  • the decay constant ⁇ ⁇ and the growth constant ⁇ ⁇ of the phosphor LED 122 are given as a function of the wavelength in Figures 8A and 8B, respectively.
  • the decay constant ⁇ ⁇ and the growth constant ⁇ ⁇ of the phosphor LED 122, whose spectrum is shown in Fig 7B, are given as a function of the wavelength in Figures 9A and 9B, respectively.
  • Figures 8A and 9A show the respective decay constants ⁇ ⁇ in ms, indicated by reference sign 228, on the y-axis 196 versus the wavelength in nm 198 on the x-axis 200; and Figures 8B and 9B show the respective growth constants ⁇ ⁇ in ms, indicated by reference sign 230, on the y-axis 196 versus the wavelength in nm 198 on the x-axis 200. Data points from different repetition measurements are marked in different shades of grey.
  • a further characteristic of the LED 118 is the light output power as a function of the forward current. Thus, generally, by increasing the forward current, specifically the input current, the power emitted by the LED 118 is increased.
  • the shape e.g.
  • Figure 10 shows an example of such a curve. Specifically, in the diagram in Figure 10, the normalized light output 232 of a phosphor LED 122 is shown as a function of the forward current 234, which is given in Ampere.
  • Figure 11 shows a diagram representing a standard operation scheme and a pulse modulation scheme for driving the light source 114 of the spectrometer device 110 during a measurement.
  • the horizontal axis 236 of the graph refers to the time in arbitrary units.
  • the vertical axis 238 refers to the power of the primary light in arbitrary units.
  • Figure 12 shows a graph representing temperature profiles of the light source 114 based on the schemes illustrated by Figure 11.
  • the horizontal axis 240 of the graph refers to the time in arbitrary units.
  • the vertical axis 242 refers to the temperature in arbitrary units.
  • Figure 13 shows a graph representing the secondary light’s emission power of the light source 114 based on the schemes of Figure 11 and based on the corresponding temperature profiles depicted by Figure 12.
  • the horizontal axis 244 of the graph refers to the time in arbitrary units.
  • the vertical axis 246 refers to the power of the secondary light in arbitrary units.
  • a curve 248 illustrates a power profile of the pump light according to an exemplary scheme for a standard operation of the spectrometer device 110, wherein the power of the pump light is kept constant.
  • a heat up of the spectrometer device 110 in particular of the light source 114 of the spectrometer device 110.
  • This heat up is illustrated by curve 250 depicted by Figure 12, wherein curve 250 illustrates the temperature profile of the light source 114 for the standard operation.
  • curve 250 illustrates the temperature profile of the light source 114 for the standard operation.
  • the emission power of the secondary light for the standard operation scheme is illustrated by curve 252 of Figure 13.
  • a square wave signal 254 illustrates a power profile of the pump light according to an exemplary pulse modulation scheme for driving the light source 114, in particular during one measurement.
  • the square wave signal 254 of the pulse modulation scheme is modulated with a variable duty cycle.
  • the pulse modulation scheme may be employed for modulating the power of primary light, such as blue light, during a measurement to keep the power of secondary light, such as infrared light, stable during one measurement.
  • Figure 14 shows a flowchart of an embodiment of method of obtaining spectroscopic information on the at least one object 112. The method comprises the following steps that may be performed in the given order.
  • the method comprises: a.
  • the driving unit 138 is configured for driving the light source 114 in a manner that the light-emitting diode 118 is generating the primary light, wherein the light-emitting diode is driven with a pulse modulation scheme having a variable duty cycle for controlling an emission power of the secondary light, wherein the duty cycle is varied based on an influencing parameter having an influence on the light-conversion efficiency of the luminescent material 120; b.
  • a spectrometer device 110 (denoted by reference number 262) illuminating the object 112 with illumination light 116 generated by the light source 114; c. (denoted by reference number 264) detecting detection light from the object 112 and generating at least one detector signal, by using at least one detector; d. (denoted by reference number 266) evaluating at least one detector signal generated by the detector by using at least one evaluation unit 136 and deriving the spectroscopic information on the object 112 from the detector signal, by using the evaluation unit.
  • a spectrometer device 110 such as according to the exemplary embodiment shown in Figure 1 and/or according to any other embodiment disclosed herein, may be used.
  • Figure 1 for a detailed description of the spectrometer device 110, reference is made to the description of Figure 1.

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Testing Of Optical Devices Or Fibers (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Spectrometry And Color Measurement (AREA)

Abstract

L'invention concerne un dispositif spectrométrique (110) permettant d'obtenir des informations spectroscopiques sur au moins un objet (112). Le dispositif spectrométrique (110) comprend : i) au moins une source lumineuse (114) pour générer de la lumière d'éclairage (116) pour éclairer l'objet (112), la source lumineuse (114) comprenant au moins une diode électroluminescente (118) pour générer de la lumière primaire et au moins un matériau luminescent (120) pour la conversion de la lumière primaire en lumière secondaire ; ii) au moins un détecteur pour détecter la lumière de détection provenant de l'objet (112) et pour générer au moins un signal de détecteur ; iii) au moins une unité de commande (138) pour commander la source lumineuse (114) de manière à ce que la diode électroluminescente (118) génère la lumière primaire, la diode électroluminescente (118) étant commandée par un schéma de modulation d'impulsions ayant un cycle de service variable pour commander une puissance d'émission de la lumière secondaire, le cycle de service étant modifié en fonction d'un paramètre ayant une influence sur l'efficacité de conversion de lumière du matériau luminescent (120) ; et iv) au moins une unité d'évaluation (136) pour évaluer le signal du détecteur généré par le détecteur et pour dériver les informations spectroscopiques sur l'objet (112) à partir du signal du détecteur. En outre, l'invention concerne un procédé correspondant d'obtention d'informations spectroscopiques sur au moins un objet (112).
EP24705702.9A 2023-02-23 2024-02-22 Del de commande avec schéma de modulation d'impulsions à cycle de service variable Pending EP4669938A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
EP23158158 2023-02-23
EP23169862 2023-04-25
PCT/EP2024/054547 WO2024175726A1 (fr) 2023-02-23 2024-02-22 Del de commande avec schéma de modulation d'impulsions à cycle de service variable

Publications (1)

Publication Number Publication Date
EP4669938A1 true EP4669938A1 (fr) 2025-12-31

Family

ID=89977798

Family Applications (1)

Application Number Title Priority Date Filing Date
EP24705702.9A Pending EP4669938A1 (fr) 2023-02-23 2024-02-22 Del de commande avec schéma de modulation d'impulsions à cycle de service variable

Country Status (5)

Country Link
EP (1) EP4669938A1 (fr)
JP (1) JP2026509183A (fr)
KR (1) KR20250152651A (fr)
CN (1) CN120769975A (fr)
WO (1) WO2024175726A1 (fr)

Family Cites Families (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5475221A (en) 1994-05-11 1995-12-12 Brimrose Corporation Of America Optical spectrometer using light emitting diode array
US6667802B2 (en) 2001-02-12 2003-12-23 Analytical Spectral Devices, Inc. System and method for self-referencing calibration
US6717669B2 (en) 2002-03-06 2004-04-06 Sci Instruments, Inc. Self-calibrating spectrometers and auto-calibration methods
US7061618B2 (en) 2003-10-17 2006-06-13 Axsun Technologies, Inc. Integrated spectroscopy system
EP2132542A4 (fr) 2007-04-03 2014-01-08 Mutoh Ind Ltd Spectrophotomètre et procédé
CN101821603A (zh) 2007-10-11 2010-09-01 巴斯夫欧洲公司 具有led阵列的分光仪
US8164050B2 (en) 2009-11-06 2012-04-24 Precision Energy Services, Inc. Multi-channel source assembly for downhole spectroscopy
CN105593651B (zh) 2013-08-02 2019-06-07 威利食品有限公司 光谱测定系统和方法、光谱设备和系统
DE102014013848B4 (de) 2014-09-24 2016-08-04 Insion Gmbh Mikrospektrometer, Mikrospektrometersystem und Kalibrationsverfahren
DE102015106757A1 (de) * 2015-04-30 2016-11-03 Osram Opto Semiconductors Gmbh Strahlungsemittierendes optoelektronisches Bauelement
US9360366B1 (en) 2015-10-08 2016-06-07 Chuong Van Tran Self-referencing spectrometer on mobile computing device
KR102729488B1 (ko) * 2016-11-08 2024-11-12 삼성전자주식회사 분광기, 생체정보 측정 장치 및 방법
US20180172510A1 (en) * 2016-12-08 2018-06-21 Verifood, Ltd. Spectrometry system applications
US11085825B2 (en) 2018-03-30 2021-08-10 Si-Ware Systems Self-referenced spectrometer
DE102018213377A1 (de) 2018-08-09 2020-02-13 Robert Bosch Gmbh Spektrometer und Verfahren zur Kalibrierung des Spektrometers
WO2020217670A1 (fr) 2019-04-24 2020-10-29 パナソニックＩｐマネジメント株式会社 Dispositif électroluminescent, et système médical, appareil électronique et procédé d'inspection l'utilisant

Also Published As

Publication number Publication date
KR20250152651A (ko) 2025-10-23
JP2026509183A (ja) 2026-03-17
WO2024175726A1 (fr) 2024-08-29
CN120769975A (zh) 2025-10-10

Similar Documents

Publication Publication Date Title
WO2024175712A1 (fr) Étalonnage sur site d'échelle de longueur d'onde de dispositif spectrométrique
WO2024175726A1 (fr) Del de commande avec schéma de modulation d'impulsions à cycle de service variable
WO2024175714A1 (fr) Système de spectromètre utilisant une longueur d'onde sans dérive
WO2024175710A1 (fr) Correction de spectre d'infrarouge proche sur la base d'une mesure de tension directe
WO2024223627A1 (fr) Fonctionnement à deux del avec pilote unique
WO2024175709A1 (fr) Étalonnage de propriétés thermoélectriques et thermo-optiques en usine ou sur le terrain
WO2024175733A1 (fr) PRISE EN COMPTE D'UNE PLURALITÉ DE CONSTANTES DE TEMPS τ POUR OBTENIR DES INFORMATIONS SPECTROSCOPIQUES
WO2024175711A1 (fr) Détermination d'informations de température sur une source de lumière à partir d'une déformation de spectre
CN120693501A (zh) 考虑时间常数来获得光谱学信息
EP4698864A1 (fr) Dispositif spectrométrique pour obtention d'informations spectroscopiques sur au moins un objet
EP4673708A1 (fr) Installation de mesure de température de del par l'intermédiaire d'un circuit d'injection directe tamponnée (bdi)
EP4698863A1 (fr) Spectromètre à source de lumière de pompage et à rayonnement fluorescent
WO2024180026A1 (fr) Mesure synchrone de polarisation et de tension de référence pour la correction de signal d'un élément photosensible
WO2025233271A1 (fr) Procédé de détermination continue d'informations de température pour unité d'éclairage
WO2024218200A1 (fr) Spectromètre à source de lumière de pompage et à rayonnement fluorescent
WO2025196063A1 (fr) Modulation de longueur d'onde de del par courant d'excitation pour une spectroscopie
WO2025172370A1 (fr) Procédé d'étalonnage de spectromètre
WO2025242754A1 (fr) Étalonnage pour spectroscopie basé sur une relation de signaux de del

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: UNKNOWN

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20250923

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR