Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
  • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
  • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2223/00—Investigating materials by wave or particle radiation
  • G01N2223/40—Imaging
  • G01N2223/419—Imaging computed tomograph

Definitions

• Sensor device for detecting radiation, in particular X-radiation, for checking a workpiece
• the present invention relates to a sensor device for detecting radiation, comprising an optical sensor for detecting light in a first wavelength range, an optical converter which, depending on the radiation incident on the optical transducer, has light in the first wavelength range and imaging optics for imaging the light emitted from the optical transducer onto the optical sensor, the imaging optics comprising at least one optical element, and shielding means for shielding the optical sensor from the radiation.
• the present invention relates to a sensor system with a plurality of sensor devices according to the first aspect of the invention.
• the present invention according to a third aspect relates to a measuring system with a sensor device according to the first aspect of the invention or with a sensor device according to the second aspect of the invention.
• Measuring systems that use X-radiation, ⁇ -radiation or particle radiation to inspect an object are well known in the art.
• applications in microscopes or for checking workpieces are also known.
• measurement systems operating in X-ray quality used in quality assurance make it possible to examine a manufactured workpiece according to material defects which can not be detected by a visual inspection.
• An example of such measuring devices is the applicant's series marketed under the name "Metrotom®".
• a scintillator usual, ie for sensitive light in a visible spectral range of 380 nm to 780 nm, optical sensors to make usable.
• the scintillator can emit light in a visible spectral range or in the ultraviolet or infrared spectral range depending on the radiation irradiating it, which is then detected by an optical sensor, eg a PMT (photomultiplier), a photodiode, an avalanche diode or a CCD. or CMOS camera can be detected.
• an optical sensor eg a PMT (photomultiplier), a photodiode, an avalanche diode or a CCD. or CMOS camera can be detected.
• Such optical sensors are widely used and relatively cheap.
• a problem is regularly that such optical sensors, if they are a high-energy radiation, for example. A ⁇ -radiation or X-radiation be exposed to strong aging effects. The lifetime of the sensors is then very low
• document US 2006/0192129 A1 shows a microscope operating with X-ray radiation.
• the CCD camera is inevitably exposed by the X-ray strong aging effects.
• high energy radiation such as ⁇ -radiation and very short wavelength X-ray, has a refractive index of about 1 in almost all materials.
• a linear structure proposed in this publication inevitably leads to the CCD camera being constantly exposed to X-rays.
• the proposed arrangements there require mandatory reflective optical elements in addition to the imaging optics per se, to effect the desired beam deflection.
• these additional reflective optical elements are likewise located in the direct beam path of the high-energy radiation, for example the X-ray radiation.
• the quality of such a sensor system depends very much on the quality of such a reflective element, since there errors directly affect the image captured by the optical sensor.
• a first aspect of the invention is therefore proposed to develop the aforementioned sensor device to the effect that a running through the optical converter, in particular the light emitting object plane of the imaging optics and extending through the optical sensor image plane of the imaging optics intersect, wherein the light hits the imaging optics directly.
• the term "radiation” is understood in the present case any type of electromagnetic radiation or particle radiation.
• the “radiation” is X-radiation or ⁇ -radiation.
• X-radiation can be understood to mean electromagnetic radiation in a wavelength range from about 10 pm to about 50 nm.
• electromagnetic waves can be understood in a wavelength range of less than 10 pm.
• the particle beams may be ⁇ radiation, ⁇ radiation or neutron radiation.
• the “radiation” can also be radiation in the ultraviolet range, for example in a range from 50 nm to about 200 nm. The “radiation” is thus high-energy radiation.
• optical converter is understood to mean a component which, when irradiated by “radiation”, emits electromagnetic radiation in a specific wavelength range, in particular of light in a wavelength range. range from about 380 nm to about 780 nm.
• An example of such an optical converter is a scintillator.
• the optical transducer emits electromagnetic radiation in the ultraviolet range from about 200 nm to about 380 nm or emits in a near infrared range from 780 nm to about 2500 nm.
• the wavelength range in which the optical transducer emits the light is the "first wavelength range", the optical sensor is sensitive to this first wavelength range and can thus detect the light emitted by the optical transducer.
• An “imaging optics” is understood to be the at least one optical element which images the light emitted by the optical converter onto the optical sensor.
• the imaging optics thus has a focusing effect.
• a plane mirror which has no focusing effect is thus not the first optical element to which the light emitted by the optical converter hits.
• at least one reflecting mirror may be provided in principle, for example, in order to fold the beam path and / or keep it compact. However, this is not involved in an imaging property of the imaging optics.
• the light emitted by the optical converter directly hits the imaging optics without influencing by further optical elements.
• no further elements for influencing the beam path are provided between the imaging optics and the optical converter in the beam path of the light.
• no plane mirrors are provided for the reflection of the light. It is thus proposed to let the light emitted by the optical converter directly strike the imaging optics and to focus on the optical sensor.
• an object plane extending through the optical converter is at an angle to one another on the image plane extending through the optical sensor or parallel to the sensor elements of the optical sensor.
• the object plane and the image plane intersect.
• the optical sensor can thus be arranged behind the shielding device in a secured area.
• the imaging optics is accordingly designed such that, although the image plane and the object plane are not parallel to one another, a sharp imaging of the object plane on the image plane takes place. This makes it possible in particular to dispense with reflecting mirrors within the beam path of the radiation.
• the area which has become free due to the omission of any reflecting mirrors makes possible an uninfluenced further propagation of the radiation, in particular of X-ray radiation.
• the only influence on the radiation thus occurs in the transmission of the optical converter.
• the design of the optical transducer can be made with knowledge of the materials used for it such that the influence of the radiation is known by the optical transducer.
• radiation curing caused by the optical transducer i. Filtering soft or long-wave radiation components, can be known in advance. In this way one is able to know the properties of the radiation after penetration of the optical transducer of the sensor device. Since there is no further influencing of the radiation in the free space behind the optical converter, it is possible to determine additional information about this radiation at a further location once it has penetrated the optical converter of the sensor device. This enables new methods of detection and evaluation of the radiation.
• the sensor system according to the invention according to a second aspect proposes to provide a first sensor device according to the first aspect of the invention and at least one second sensor device according to the first aspect of the invention, wherein the optical transducer of the first sensor device and the optical Transducer of the at least one second sensor device with respect to an incident direction of the radiation are arranged one behind the other.
• the "direction of incidence” is understood to mean the main direction in which the radiation is incident on the optical transducer of the first sensor device and the optical transducer of the second sensor device.
• an optical transducer will have a substantially disc-like geometry.
• the optical transducer has a relatively large front and rear surface and, moreover, a relatively small thickness with respect to the dimensions of the surface of the front and rear surfaces.
• the "direction of incidence” is then perpendicular to the front and back surfaces of the optical transducer.
• a measuring system for testing a workpiece which has a radiation source emitting radiation, in particular wherein the radiation penetrates the workpiece, and further a sensor device according to the first aspect of the invention or a sensor system according to the second aspect of the invention.
• the measuring system thus comprises either a sensor device according to the first aspect or a sensor system according to the second aspect and therefore provides the same advantages.
• a method for determining a propagation direction of a radiation with the following steps is made possible according to the invention: Providing a sensor system, wherein at least one difference vector between a first location of the optical converter of the first sensor device and a second location of the optical converter of the at least one second sensor device is known,
• scaling would be the simplest case - as the radiation from the X-ray source propagates in a straight line - to assume a steady widening of the beam from the source to the transducer in the detector.
• the images scale like the distances of the transducer from the radiation source or X-ray source.
• the cascading i. arranging a plurality of optical transducers of the sensor devices in succession in an incident direction of the radiation, it is thus possible to successively filter certain areas of the radiation and to determine the energy fractions attributable to them.
• the imaging optics is configured such that the imaging optical system images the object plane sharply on the image plane.
• the radiation can be detected with high accuracy.
• the sharp image of the light emitted by the optical transducer on the Image plane or the sensor plane of the optical sensor allows the best evaluation of the light emitted by the optical converter.
• the imaging optics consists of the at least one optical element, and wherein each optical element of the imaging optics from a group consisting of a refractive optical element, a diffractive optical Element and a holographic optical element is selected.
• an object plane extending through the optical converter in particular the light emitting object plane of the imaging optics and an image plane passing through the optical sensor the imaging optics intersect, in particular wherein the at least one optical element is a refractive optical element or diffractive optical element or holographic optical element, and wherein the optical transducer, the imaging optics and the optical sensor are arranged in compliance with the Scheimpflug- condition relative to each other.
• This embodiment is particularly understood as an independent aspect of the invention and forms together with the preamble of claim 1 and without the further characterizing features of claim 1 an independent subject of the invention.
• a sensor device for detecting radiation, with an optical sensor for detecting light in a first wavelength range, an optical converter, which depends on the on the optical transducer incident radiation emits light in the first wavelength range, imaging optics for imaging the light emitted from the optical transducer onto the optical sensor, the imaging optics having at least one optical element, and shielding means for shielding the optical sensor from the radiation, one of the optical system, in particular the light emitting, object plane of the imaging optics and a plane passing through the optical sensor image plane of the imaging optics intersect, in particular wherein the at least one optical element is a refractive optical element or diffractive optical element or holographic optical element, and wherein the optical converters, the imaging optics and the optical sensor are arranged in compliance with the Scheimpflug condition relative to each other.
• the optical sensor in a safe area behind the shield in front of the radiation, in particular the X-ray radiation.
• the image plane extending through the sensor surface of the optical sensor and an object plane of the imaging optical system passing through the optical converter intersect in a cutting axis.
• the imaging optics is now to be arranged in this embodiment so that the Scheimpflug condition is met.
• the sharp imaging of the object plane on the image plane can be ensured.
• the Scheimpflug condition or the Scheimpflug rule states that, for a sharp optical image, the image plane, the focal plane or object plane and the objective plane must intersect in a common straight line.
• the lens plane is the main plane of the lens. In the present case, therefore, the main plane of the imaging optics. In the construction of the imaging optics from only a single refractive optical element, the main plane of the optical element is at the same time the main plane of the imaging optics or of the objective. In a construction of the imaging optics of a plurality of optical elements, the imaging optics or the lens will have, for example, two main planes, an object-side main plane and an image-side main plane.
• the Scheimpflug condition is then exactly that the focal plane or object plane with the object-side main plane at the same distance from the optical axis of the lens intersects as the image plane with the image-side main plane of the lens or the imaging optics, wherein both intersecting lines are parallel to each other. Both degrees of cutting are also located on the same side of the optical axis of the imaging optics. The intersection line could also coincide, which means that the individual elements in the imaging optics are also tilted towards each other.
• an imaging optics can thus be designed for the average person skilled in the art, which images the light emitted by the optical converter sharply onto the optical sensor.
• the entire area of the optical transducer, i. the object plane sharply imaged on the image plane.
• imaging optics eliminates any need to reflect mirrors, etc. in a beam path of the radiation, in particular the X-rays, to arrange to redirect the light suitable for the optical sensor.
• a suitable imaging optics can be provided.
• the at least one optical element is a diffractive optical element. In yet another embodiment it can be provided that the at least one optical element is a holographic optical element.
• the task can be solved to focus the light on the optical sensor or the image plane.
• a diffractive optical element or a holographic optical element generally has a lower weight and smaller dimensions than, for example, an imaging optic formed from refractive optical elements.
• the at least one optical element and the optical transducer are arranged directly adjacent to each other.
• the optical converter and the optical element have no air gap between them.
• the sensor device further comprises a socket device which carries both the optical transducer and the at least one optical element.
• the optical converter and the at least one optical element are thus held together in a housing part or a housing section which forms the mounting device.
• a design of a diffractive optical element or a holographic optical element can be simplified once again by fixing the relative positioning of the diffractive optical element or the holographic optical element and the optical transducer by means of the mounting device. It can also be provided that the at least one diffractive optical element or the at least one holographic optical element is integrated into the optical converter is. By “integrated” is meant a one-piece, non-destructive separable connection.
• the imaging optics has more than one optical element, wherein the imaging optics comprises a first optical element, which is a diffractive optical element or a holographic optical element, and at least a second optical element, and wherein the first optical element is disposed immediately adjacent to the optical transducer.
• a combination of a refractive optical element with a diffractive or holographic optical element is conceivable.
• a design of the diffractive optical element or of a holographic optical element may possibly be simplified, since a deflection to be effected by the diffractive optical element or the holographic optical element can be kept smaller and is additionally assisted by the refractive optical element.
• the at least one second optical element can furthermore be formed from a plurality of refractive optical elements as refractive optics, which is part of the imaging optics.
• the above-mentioned Scheimpflug condition is maintained such that it, in particular only, for the refractive optical elements formed refractive part of the optics with his or her main axes, the image plane in the optical sensor and an object plane is complied with.
• the object plane in this case run through the diffractive or holographic optical element or, as usual, through the optical converter.
• the angle may be greater than 20 °, in particular greater than 30 °, in particular greater than 45 °.
• the optical transducer is a scintillator.
• a scintillator is a body that is excited during the passage of high-energy photons or high-energy radiation or charged particles or particle radiation and the excitation energy in the form of light, usually in the visible spectral range, but also, for example, in the ultraviolet range, gives up again.
• the emitted light can then be deflected by the imaging optics and detected by the optical sensor.
• By measuring the amount of light e.g. By means of a photomultiplier or a photodiode, it is possible to deduce directly the energy emitted by the radiation to the scintillator.
• the optical sensor is a CCD (charge-coupled device) camera or a CMOS (complementary metal oxide semiconductor) camera.
• the optical sensor can also be any type of photomultiplier, photodiode, avalanche diode or multiple numbers or a two-dimensional array structure thereof.
• it can be provided to use so-called Lin-Iog CMOS sensors. These have a linear response in a first region and a logarithmic response in a second region.
• a linear response may be implemented for low illuminance and a logarithm response for high illuminance.
• the radiation is an electromagnetic radiation, in particular an X-radiation or a ⁇ -radiation, or a particle radiation.
• the shielding device, the imaging optics and the optical sensor are arranged such that the shielding device shields both the optical sensor and the imaging optics.
• the shielding device can also serve as a carrier device for elements of the sensor device.
• the imaging optics can be placed in a safe area by not directly exposed to the radiation.
• a structure is applied to the optical signal converter, which allows a scaling and / or distortion correction of the image on the optical sensor.
• the structure may be a uniform grid.
• the structure may also be exposed to the optical transducer.
• a surface of the optical transducer is roughened to make the structure visible in the image detected by the optical sensor.
• this surface can be one of the surfaces facing the optical sensor or one of the surfaces of the optical converter incident on the optical transducer.
• the optical transducer may be e.g. be formed by a face plate.
• Such a face plate is easy to replace by a customer or user.
• An optical transducer would then represent a wearing part that can be easily and inexpensively replaced. In particular, no special service personnel with specialist knowledge are required for this exchange.
• the optical converter In order to be able to produce sharp images on the image plane of the optical sensor, the optical converter should have a not too large thickness.
• thickness is meant a longitudinal extent of the optical transducer in the direction of the incident radiation.
• the optical converter may not be too thin to generate sufficiently many photons per radiating energy.
• the optical transducer may have a thickness in a range of about 0.1 mm to about 10 mm.
• a carrier surface or substrate is provided for supporting the optical converter.
• a material of this carrier should have a small effective mass number, for example, from a lightweight material or porous material, such as, for example, be made of magnesium.
• structures can be introduced into the support, which allow a thickness calibration of the dose for linearity correction of the optical sensor.
• a linearity correction of the optical sensor is performed in order to correct any non-linearities of the readout and amplifier circuits of the optical sensor or a non-linear behavior of the optical sensors at long exposure times.
• the optical transducer itself can exhibit nonlinear behavior based on the time-limited regeneration capability of the fluorescence transitions, also referred to as "depletion.” This behavior can also be corrected.
• the sensor device has an auxiliary light source which emits light in a known spectrum and energy or power.
• the auxiliary light source is arranged such that it illuminates the optical transducer.
• the auxiliary light source is arranged such that it directly or directly illuminates the optical sensor.
• At least one filter for filtering a portion of the radiation is arranged between the optical transducer of the first sensor device and the optical converter of the at least one second sensor device.
• the filter and the optical transducer are directly attached to each other.
• the filter and the optical converter may be constructed as one unit.
• a filter can be provided, for example, in the form of an absorbent coating, as a film, or as a disk of suitable material. Even a suitable choice of the material of the optical transducer can already bring about a desired filter effect.
• the sensitivity can be increased compared to the pure X-ray detectors, for example in one embodiment of the sensor system or the measuring system Sensor device also look laterally at an angle to a transmission direction of a radiation beam through the measurement object on the measurement object.
• this sensor device can detect only the X-ray scattered light and thus can detect further features - in particular structural features - of the measurement object.
• this structure in combination with an optical sensor based on the above-mentioned Lin-log CMOS technology may be advantageous due to the large dynamic range.
• the offset of the correlated image components from the first optical converter to the second optical converter can be determined.
• a three-dimensional propagation vector of the radiation can be determined.
• errors for example. An undesirable cavity in the workpiece, not only captured in the image, but immediately the position of the error are determined.
• an absorption coefficient or the optical density (absorption capacity) of the workpiece with knowledge of a radiation source emitting radiation can be determined on the basis of at least the first image.
• the above-mentioned method for determining a propagation direction is carried out and the method for determining an energy distribution within a radiation is performed wherein the step of determining the difference image is performed for respective correlated image portions of the first image and the second image.
• the combination of the two proposed methods can be carried out not only in the back projection of certain pixels on the workpiece, but also determine the energy information for specific spectral regions separately. insofar can be, with knowledge of a corresponding spectrally resolved information about the radiation source, determine a corresponding spectrally resolved absorption coefficient of the workpiece.
• devices are provided by the present invention and enables methods that allow novel evaluation options of radiation.
• This is possible in particular by a so-called “multi-shell evaluation" of the radiation, since according to the invention an evaluation of the radiation at different distances from the radiation source or a workpiece penetrated by the radiation is possible.
• FIG. 1 shows an embodiment of a sensor device according to the invention
• 4 shows an embodiment of a sensor system
• 5 shows an embodiment of a method for determining a propagation direction of a radiation
• FIG. 6 shows a method for determining an energy distribution of a radiation.
• the sensor device 10 serves to detect a radiation 12.
• the radiation 12 may in principle be electromagnetic radiation or else particle radiation or particle radiation.
• the radiation 12 may be X-radiation.
• the embodiments of the invention will be explained using the example of X-ray radiation.
• an optical converter 14 is provided.
• the optical transducer 14 is excited by the energy of the radiation 12 to emit light 16.
• the light 16 may be light in a visible wavelength range. However, it may also be provided, depending on the choice of the optical transducer 14, that light is emitted on an ultraviolet or infrared spectrum.
• the optical converter 14 may be a scintillator.
• various materials both organic and inorganic materials, are known, with which a scintillator can be provided.
• the scintillator 14 has approximately the shape of a disk.
• the optical transducer 14 has an areal extent in an XY plane, for example in the form of a rectangle.
• the optical transducer 14 has a certain thickness D extending in the Z direction. This thickness D extends approximately in the direction in which the radiation 12 penetrates the optical transducer 14.
• the usual thickness D for the optical transducer 14 is 0.1 to 10 mm.
• the optical transducer 14 depending on the material of the optical transducer 14, it is not too thin to be chosen so that the optical transducer 14 can emit a sufficient amount of photons in the form of the light 16, but on the other hand it is not too bright thick so that the output from the optical transducer 14 in the form of light 16 has sharp contours.
• the light 16 emitted by the optical converter 14 is then detected by an optical sensor 18.
• the optical sensor 18 is chosen such that it is sensitive to the wavelength range in which the light 16 is emitted.
• the optical sensor 18 may be capable of detecting, in the manner of a photomultiplier, the number of photons impinging on the optical sensor 18.
• optical transducer 14 and optical sensor 18 high-energy radiation 12 is able to be generated with an optical sensor 18 which is sensitive to light in a customary wavelength spectrum, which is generally visible to the human eye , For example, to detect an X-ray radiation.
• an imaging optics 20 is provided.
• the imaging optics 20 are capable of focusing the light 16 onto the optical sensor 18. This is made possible according to the invention without the aid of merely reflecting elements, such as plane mirrors, in a beam path of the light 16 between the optical transducer 14 and the imaging optics 20.
• the light 16, which is emitted by the optical converter 14, thus falls directly onto the imaging optics 20.
• the imaging optics 20 has at least one optical element 22, with which the light 16 is then focused onto the optical sensor 18.
• the imaging optical unit 20 has an optical element 22, which is shown in the form of a lens in the form of a refractive optical element.
• the imaging optics 20 has more than one optical element 22, in particular more than one refractive optical element 22. Furthermore, as explained below The imaging optics 20 may also be formed with at least one optical element 22 which is a diffractive or a holographic optical element.
• the sensor device 10 has a shielding device 24.
• the shielding device 24 serves to shield the optical sensor 18 from the radiation 12.
• the arrangement and dimensioning of the shielding device 24 in FIG. 1 is merely an example.
• a radiation 12 which is, for example, an X-ray
• X-ray it can be assumed that it propagates isotropically substantially straightforwardly through each type of matter.
• all materials essentially have a refractive index of 1, so that substantially no beam deflection occurs.
• the radiation 12 continues straight after transmission through the optical converter 14.
• the optical sensor 18 is to be located outside a region where the radiation 12 would enter when propagated rectilinearly. Only there can the optical sensor 18 be shielded by means of the shielding device 24 in such a way that at the same time the optical sensor 18 has the possibility of detecting the light 16 emitted by the optical converter 14.
• the light 16 emitted by the optical converter 14 is essentially a two-dimensional image that allows a conclusion about the spatial distribution and the spatial energy distribution of the radiation 12 in the XY plane. Accordingly, the imaging optics 20 must be capable of imaging the light 16 emitted in an XY plane sharply on the optical sensor 18, which is located substantially in an XZ plane in the representation selected in FIG.
• the optical sensor 18 has a two-dimensional sensor array. This would extend in the representation selected in FIG. 1 in the XZ plane and is referred to as sensor plane 26. Accordingly, an image plane, into which the imaging optics 20 must emit the light emitted by the optical transducer 14 16 sharp, parallel to the sensor plane 26. The image plane is designated by the reference numeral 28. An object plane 30 of the imaging optics 20 then extends in the view shown in Fig. 1 in the X-Y plane parallel to the optical transducer 14 therethrough. Depending on the thickness D of the optical transducer 14, the object plane 30 may extend, for example, exactly through a center D / 2 of the optical transducer 14.
• the imaging optics 20 is now configured and arranged such that the object plane 30 is imaged sharply onto the image plane 28.
• the at least one optical element 22 is a refractive optical element
• a sharp image of the object plane 30 can be made on the image plane 28 by the optical transducer 14, the optical sensor 18 and the imaging optics 20 and 20, respectively.
• the at least one optical element 22 are arranged such that the Scheimpflug condition is met.
• the imaging optical unit 20 has a refractive optical element 22.
• a main plane of the optical element 22 is designated by the reference numeral 34.
• the Scheimpflug condition is only met exactly when the object plane 30, the image plane 28 and the main plane 34 intersect in a section axis 32.
• FIG. 2 shows an embodiment of a measuring system 43 in which the sensor device 10 can be used.
• the optical transducer 14 is arranged such that it is arranged substantially perpendicular to an incident direction 36 of the radiation 12.
• One of the radiation 12 facing incident surface 38 of the optical transducer 14 is thus substantially perpendicular to the direction of incidence 36 of the radiation 12.
• the radiation 12 is emitted by a radiation source 40.
• the radiation source 40 and the sensor device 10 are arranged in a stationary manner.
• the radiation source 40 and the sensor device 10 are movable in such a way that they move absolutely but not relative to one another.
• the workpiece 42 is disposed between the radiation source 40 and the optical transducer 14 of the sensor device 10.
• a workpiece holder (not shown) may be arranged to clamp the workpiece 42, for example.
• Such a workpiece holder can for example also be designed such that the workpiece 42 can be rotated or moved transversely.
• the workpiece 42 is arranged on a turntable.
• the shielding device 24 is designed and arranged such that it shields both the optical sensor 18 and the imaging optics 20 from the radiation 12. In this way it is possible to protect the imaging optics 20 from damaging influences of the radiation 12.
• the measuring system 43 may further comprise a data processing device 14 and a user interface 16.
• the data processing device 1 14 for example, the measured values detected by means of the optical sensor 18 can be read out, evaluated and output.
• the user interface 1 16 may have a suitable display device.
• the user interface 16 may include a suitable input unit that allows a user to control the measurement system 43.
• the space 33 "behind" the optical transducer 14, that is, on the incident direction 36 of the radiation 12 opposite side of the optical transducer 14, remains free.
• An influence on the radiation 12 or the light 16 in the space 33 thus remains off.
• a radiation 12 which is uninfluenced in the space 33 can be evaluated in this way at further locations or at different distances from the radiation source 40 or the workpiece 42. This will be explained in more detail below.
• FIG. 3 shows a further embodiment of a sensor device.
• the shielding device 24 is first of all designed and arranged such that it protects the optical sensor 18 and also the optical element 22, in particular the refractive optical element 22, from being influenced by the radiation 12.
• the imaging optics 20 also have a further optical element 46, 46 'beyond the optical element 22.
• the optical element 46, 46 ' may, for example, be a diffractive optical element 46 or a holographic optical element 46'.
• the diffractive optical element 46 or the holographic optical element 46 ' is arranged directly adjacent to the optical transducer 14. In this way it may be possible for the light 16 emitted by the optical converter 14 to already have an effect in the direction caused by a diffraction effect deliberately caused by the diffractive optical element 46 or by the interference or diffraction pattern deposited on the holographic element 46 ' of the optical sensor 18 to deflect. The beam deflections to be effected by the other optical elements of the imaging optics 20 can be reduced in this way. In principle, it is even possible that the diffractive optical element 46 or the holographic optical element 46 'are provided in isolation and already effect the necessary focusing of the object plane 30 on the image plane 28. In this case, the imaging optics 20 are thus provided only from a diffractive optical element 46 or only from a holographic optical element 46 '.
• the image plane 28 and the object plane 30 enclose an angle 44 between them.
• the angle 44 is about 90 °.
• the angle 44 also assumes a different value.
• the angle 44 is more than 10 °, in particular more than 20 °, in particular more than 30 °, in particular more than 45 °.
• the angle 44 is more than 10 °, in particular more than 20 °, in particular more than 30 °, in particular more than 45 °.
• the angle 44 by selecting the angle 44 of approximately 75 °, the refraction of the light 16 to be effected by the imaging optics 20 in order to image it sharply from the object plane 30 onto the image plane 28 can be reduced.
• a such angle 44 still be sufficient to shield the optical sensor 18 by means of the shielding means 24 can.
• an angle 45 included by the major axis 34 of the imaging optics 20 and the image plane 28 may be selected correspondingly with a different value.
• the angle 45 may be less than 45 °, in particular less than 30 °, in particular less than 15 °.
• FIG. 4 shows an embodiment of a sensor system 51.
• the sensor system 51 may be part of the measuring system 43.
• the sensor system 51 has more than one sensor device 10, as shown for example in the embodiments in FIGS. 1 and 3. Accordingly, in the embodiment illustrated in FIG. 1, the sensor system 51 has a total of three sensor devices 10, 48 and 50.
• the first sensor device is identified by the reference numeral 10, the second sensor device by the reference numeral 48 and the third sensor device by the reference numeral 50.
• the optical transducers 14, 14 ', 14 are arranged in a cascade one behind the other with respect to the main incident direction 36. In this way, it becomes possible to transmit the radiation 12 at different distances or at different locations Radiation source 40 and the workpiece 42. As will be explained in more detail below, this allows completely new possibilities of evaluation.
• the sensor system 51 has at least one filter element which is arranged between two optical transducers 14, 14 'or 14', 14 ".
• a first filter element 52 is disposed between the optical transducer 14 and the optical transducer 14 '
• the filter elements 52, 54 also extend flat in the XY plane
• the filter elements 52, 54 specifically filter a certain portion of the radiation 12. This may be, for example, a act specific wavelength range, if it is the radiation 12 is an electromagnetic radiation, for example, an X-ray.
• the optical converter 14 is excited to emit light.
• This light emitted in the XY plane by the optical transducer 14 is referred to as the "first image" 56. It is imaged on the optical sensor 18 via the imaging optics 20. Accordingly, a second image 58 generated by the optical transducer 14 'is imaged onto the optical sensor 18'. At the same time, a third image 60 "emitted by the optical transducer 14" is imaged onto the optical sensor 18 ".
• the evaluation of the images 56, 58, 60 of the radiation 12 generated at different distances from the workpiece 42 makes it possible to provide improved evaluation possibilities for the radiation 12.
• the "piercing point" of the radiation 12 can thus be determined, so to speak, through the object planes 30, 30 'and 30 ", the optical converter 14 at a first location 106 being the optical converter 14 'at a second location 108 and the optical transducer 14 "positioned at a third location 110.
• the locations 106, 108 and 110 are known. These are determined by the structural design of the sensor system 51. In this respect, a difference vector 1 12 between the first location 106 and the second location 108 as well as a difference vector 1 12 'between the second location 108 and the third location 110 is known.
• the optical transducers 14, 14 'and 14 are aligned parallel to one another, that is to say the object planes 30, 30' and 30" run parallel to one another. at the.
• an image correlation of the first image 56 and the second image 58 may determine an offset of the radiation 12 in the XY plane from the first image 56 to the second image 58.
• the difference vector 1 12 is known, it is possible in this way to determine a three-dimensional vector indicating a propagation direction 68 of the radiation 12.
• the number of individual sensor devices 10, 48, 50 in the sensor system 51 is merely an example. Of course, it is possible that further sensor devices are arranged in the sensor system 51.
• the optical transducers 14 can each be arranged in the described form in cascade fashion one behind the other with respect to the direction of incidence 36 of the radiation 12. In this respect, two, three, four, five, six etc. sensor devices can also be arranged one behind the other. Likewise, it is then possible not only to make image correlations between images of adjoining sensor devices, but also, for example, to correlate directly between a second image 58 and a fifth image (not shown). Any combinations are possible here.
• the sensor system 51 for example, information about the energy of a specific portion of the radiation 12 can be obtained.
• the optical transducers 14, 14 'and 14 "are provided and because of this it is also known in which context the emission of photons generated by the optical sensor 18, 18', 18 "are detected with the radiation from 12 to the A certain number of photons detected by means of, for example, the optical sensor 18 at a particular pixel of the first image 56 can be relied on the energy or irradiance of the radiation 12 as it passes through the optical transducer 14 close at this particular pixel.
• the first image 56 not only shows how the energy distribution of the radiation 12 is in the first image 56, but also the energy distribution within the image Radiation 12 from the image 58 can be determined, which hits the optical converter 14 '. Since a radiation hardening or filtering of the radiation value has already occurred in the optical converter 14, a corresponding evaluation of the second image 58 for an energy distribution will yield different results than that of the first image 56. From these differences in the energy distribution in the images 58, 56 and the knowledge about the portion of the radiation 12 filtered out during the transmission by the optical converter 14, it is thus possible to make a statement about its energy and energy distribution for precisely this filtered-out portion of the radiation 12.
• FIG. 5 schematically shows a schematic flow diagram for determining a propagation direction 68 of a radiation 12 and denoted by the reference numeral 70.
• a sensor system 51 which has at least two sensor devices 10. Furthermore, at least the difference vector 1 12 between the first location 106 of the optical converter 14 of the first sensor device 10 and the second location 108 of the optical converter 14 of the at least one further second sensor device 48 or 50 is known.
• a step 76 the first image 56 of the optical transducer 14 of the first sensor device 10 is then detected by means of the optical sensor 18 of the first sensor device 10.
• a step 78 the second image 58 of the optical transducer 14 'of the at least one second sensor device 48, 50 is detected by means of the optical sensor 18' or 18 "of the at least one second sensor device 48, 50.
• the steps 76 and 78 can basically be carried out consecutively. However, it is also possible that steps 76 and 78 are performed substantially simultaneously or simultaneously.
• a correlation result is then determined by correlating the first image 56 and the second image 58, 60.
• image correlation methods have already been proposed in the prior art. These image correlation methods make it possible to determine the mutually corresponding image portions 62, 64, 66 in the images 56, 58, 60.
• a step 82 the propagation direction 68 of the radiation 12 is then determined from the at least one difference vector 1 12, 1 12 'and the correlation result determined in step 80.
• the method may then end at step 84.
• a back projection of at least the first image 56 along the determined propagation direction 68 onto the workpiece 42 he follows. In this way, a path on which the radiation 12 has passed through the workpiece 42 can be determined.
• an absorption coefficient of the workpiece 42 is determined with the aid of at least the first image 56 with knowledge of the radiation source 40 emitting the radiation 12. Since the energy distribution of the radiation 12 can be determined in the first image 56 and, furthermore, the path of the radiation 12 through the workpiece 42 can be determined by the proposed rear projection, it is then possible for this passage through the workpiece 42 to show the absorption capacity under consideration of the energy distribution in the first image 56 compared to the values of the radiation 12 originally emitted by the radiation source 40. Finally, the method may then end in a step 84.
• FIG. 6 further schematically illustrates a method with which an energy distribution within the radiation 12 can be determined.
• This method begins in a step 92.
• the sensor system 51 is provided, wherein the sensor system 51 has at least two sensor devices 10 or 48, 50.
• a portion of the radiation filtered out by the optical transducer 14 of the first sensor device 10 as far as the respective optical transducer 14 'or 14 "of the at least one second sensor device 48, 50 is known, wherein the radiation can be detected both by an inevitably occurring radiation hardening in an optical radiation
• an additional filter element 52 or 54 is provided, with which a certain portion of the radiation 12 is specifically filtered out.
• a step 96 the first image 56 of the optical transducer 14 of the first sensor device 10 is then detected by means of the optical sensor 18 of the first sensor device 10.
• a step 98 the second image 58 or 60 of the optical transducer 14 'or 14 "of the at least one second sensor device 48, 50 is detected by the optical sensor 18', 18" of the at least one second sensor device 48, 50 , Consequently, both the second sensor device 48 and the third sensor device 50 can be understood by the "at least one second sensor device”. Accordingly, both the second image 58 and the third image 60 can be understood by the "second image”.
• a difference image is then determined from the first image 56 and the second image 58 or 60, in particular, for example, rescaled via a correlation.
• differences in energy distribution between the first image 56 and the second image 58, 60 can be determined.
• a step 102 it is thus possible to determine energy of the proportion of the radiation 12 filtered out from the optical converter 14 of the first sensor device 10 to the optical converter 14 "of the at least one second sensor device 48, 50 by means of the differential image is performed in a step 102.
• the method then ends in a step 104.
• the method 70 and 90 can be carried out, the step 100 of determining the reference image being carried out for correlating image portions 62, 64, 66 of the first image 56 and of the second images 58 and 60, respectively.

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• 2012
  • 2012-06-29 WO PCT/EP2012/062689 patent/WO2014000810A1/fr not_active Ceased

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