Classifications

• • 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

Definitions

• the invention generally makes reference to lighting bodies with light emitting diode matrix (from hereon also referred to as only LED) having as subject the lighting devices which employ the light supplied by multiple LEDs assembled on a single lighting body.
• this is a new lighting unit which comprises a series of light diodes arranged in a single housing and is capable of producing the light of a particular color, through the simultaneous activations of different light emitters, regulated by means of each related control device so that the intensities of the corresponding color emissions from each of the diodes are combined in order to supply the emission color desired by a part of the lighting body.
• Light emitting diodes are well known solid state light sources. They are widely used in many technical sectors for their low energy consumption and for their long duration. Limited by technical problems, the first LEDs were only capable of generating monochromatic light. The current LEDs are capable of generating several primary colors. In addition, LEDs have numerous advantages with respect to the traditional light sources, such as incandescent bulbs or fluorescent bulbs, since they are more economical to produce and also require less activation energy. In particular, they are preferred since they emit light with a high efficiency over specific colors of the spectrum. Nevertheless, such components do not form per se focused light sources, and for this reason suffer from relatively low output luminosity. The lack of focusing and the reduced luminosity would lead to not using LED lighting systems where a high lighting intensity is required.
• the light provided by a LED could not be intensified without the use of an optical device set for concentrating the beam.
• numerous commercial applications which require the source device to have a high luminosity with specific chromaticity of the light beam; for example, there is a considerable request for such type of lighting in the photo-film-television and stage sector.
• the lighting body is formed by an assembly of LEDs with specific colors, it is necessary to avoid problems related to color variations depending on the characteristics of the LEDs themselves, and it is appropriate to select and use the LEDs such that the light intensity and the emission wavelength of the light of the single LED falls within a certain range/field of values.
• luminosity and intensity variations luminance
• chromaticity variations of the light emission wavelength
• the COLOR RENDERING INDEX is a parameter indicative of the magnitude of the light reflected by a color sample subjected to a particular light source, compared with the light reflected by the same sample in the presence of a light source normalized at 3200°K.
• the CRI is thus used to indicate how much a light source is capable of rendering the color of the objects which are agreeably appreciable in vision. Such comparison is carried out with the aid of a predetermined eight color scale test, under sample light and in comparison with the light to be examined at 3200°K; in such case, the CRI can reach the value 100.
• the object of the present invention is that of providing a lighting body, constituted by the assembly of selected commercial LEDs, which has an optimal balancing of the color temperature parameters.
• a further object of the present invention is that of obtaining a consistent Color Rendition through the combination of a set of LEDs arranged in assembly matrices, reducing both the intensity variations and the color variations with regard to the non-homogeneity deriving from the LED production process.
• Still another object of the present invention is to provide a new lighting device with a combination of LEDs in a single housing or unit, capable of emitting a variety of colors and/or tones as a function of the energy which is supplied to the emitters supported in each housing.
• Another object of the present invention is to provide the carrier structures for matrices of lighting emitting diodes which incorporate, in addition to the light emitting devices, the circuit means for adjusting the color intensity variations at the anode of each light emitter, in a separate manner, so that any light tone can be emitted by the single lighting device, in particular the tone relative to white.
• an object of the present invention is that of supplying a light-weight lighting body with LED matrix, which employs electrical and electronic components, hardware, base software, standard technical lighting assembly containers, in order to make the system itself with limited costs, high reliability and easy maintenance.
• FIGURE 1 is a typical chromicity diagram
• FIGURES 2 A, B, C, D, E are views of a first configuration of the lighting bodies according to the present invention
• FIGURES 3 A, B, C are views of a second configuration of the lighting bodies according to the present invention
• FIGURES 4 A, B, C, D are views of a second configuration of the lighting bodies according to the present invention
• FIGURES 5 A, B, C, D are section views which highlight the expedients introduced for the heat dispersion.
• Color perception theory is currently specifically defined as described in the reported supplied by the Commission International de l'Eclairage (CIE). It is based on a chromaticity diagram of the type in FIG. 1, by means of which the resulting color is defined based on an additive combination of pure, or even impure spectral colors.
• CIE Commission International de l'Eclairage
• thermocolorimeter a photoelectric instrument which allows carrying out measurements on the light sources and on the surfaces on which the light is reflected according to the trichromatic system CIE.
• the radiation by a normal LED is "impure", since the light which is emitted is distributed over a band of wavelength values.
• the distribution of the wavelengths (or spectrum) is moreover variable from one LED to another, even when the LEDs come from the same manufacturing process.
• a lighting body can be made by using three LEDs whose colors are the nominal primary colors red, blue and green.
• a module thus formed could represent a band of chromatic values defined by a triangle whose vertices are the current colors of its component LEDs.
• the combined color that is desired and obtainable from the lighting body according to the present invention is obtained by means of the combination of only two colors, white and red/amber LEDs, present according to predefined and variable percentages in relation to the particular tone which one wishes to achieve in the emitted light beam.
• the color control in the scope of the obtainable value ranges, is carried out by means of regulation of the electric current which polarizes the anode of each LED comprised in the module.
• the band of available colors varies from one module to another due to the different spectra emitted by the LEDs.
• the CRI index having been declared unsuitable for measuring the color rendering, is only taken under consideration as information presented by leading sector manufacturers, such as LUMILEDSTM, in order to have a classification corresponding to the old CIE dictates. Except if the emission of the LEDs is in any manner compromised by the assembly in the constructed lighting bodies, it has been deemed appropriate to adapt the emission to the specific sector of interest (photo-film-television shooting) by resorting not so much to the CRI index, moreover already stated by the LED manufacturing company, but by making uniform and correlating the light response to the traditional chromatic measurement of the color temperature, deemed more suitable in practical use with the indicated materials.
• the "mixture" used therefore, produces balancing suitable for the Red - Blue correction at a color temperature of 5500° K, a chromatic correction for the remaining excess Blue and a compensation for the Green - Magenta ratio for obtaining a measure deviation not greater than 5 CC degrees (according to the unified graduated scales of KodakTM or other producers).
• the LEDs selected among the LUMILEDS products were chosen in the YO and XO areas, adding Red - Amber LEDs in a percentage ranging from 16% to 14%, in the area of 617 - 625 nanometers.
• the illuminators according to the finding are light-weight bodies with compact and simple structure formed by sets of 54 LEDs, Fig. 2, on three concentric layers of 18 LEDs each, or of 6 LEDs, Fig. 4, on two lines of 3 or 7 LEDs with circular form, Fig. 5.
• a lighting body is provided as reported in Figures 2 and 3, composed of a module comprising a series of light emitting diodes, the LEDs being installed on a power supply carrier plate, dissipator of the heat generated during emission.
• Such module comprises a dielectric structure, and a plurality of electrical conductive contacts arranged on the dielectric element.
• the contacts are configured in order to mount a series of LEDs for supplying current to the LEDs themselves.
• the assembly also comprises a conductive element of the heat produced and a box of electrical connections. Contributing to the compactness of the bodies is the structure with cell-like support plates, arranged as a radiator for facilitating the dispersion of the residue heat.
• Such plates have the object of holding, in correct position, the flow concentrator and collimator lenses designed to bring the emission from a 110° angle of the base LEDs to the angle desired according to the type of illuminator. Lateral supports hold all parts of the apparatus, allowing the modular combination of several apparatuses with suitable threads.
• the lights related to the primary colors are mixed in a reflecting recess of a base of the LEDs in order to form the light beam of a specific color, which is emitted through the housing structure of the LED matrix. It is preferable that the peripheral walls and the bottom surface of the reflecting recess are covered with a cuttering agent layer in order to provide an effective light mixing.
• a series of PINs are situated, spaced in an equidistant manner with respect to each other for the connection of the microchips, and with the other end penetrating inside the base. According to such arrangement, without increasing the volume of the LED assembly, the number of the PINs and chips is increased so as to optimally control the color of the light which must be emitted.
• a fundamental and distinctive element of the described solution is the presence of a microchip which controls: i- the possibility to reduce the power supply, in order to continuously vary the emission from 0% to 100%, ii- the separate calibration of the Red/ Amber color percentage in order to obtain creative chromatic balancing, obtaining warm or cold tints.
• Point 2 overall regulation of the light emission through an up-down button, with display in ten progressive steps.
• Point 3 manual regulation by activating the red button of the light level relative to the red LED of the LED mixture of the lighting body. At the same time, there is the insertion of the manual control of the white by means of the second function of the up-down buttons.
• Point 4. display of the low battery level with flashing red LED.
• Point 5 turning off function, via pressing the on-off button.
• the previously set values are reactivated at the subsequent starting.
• Point 7 the electronics is protected from polarity reversals.

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• Diaphragms For Electromechanical Transducers (AREA)
• Luminescent Compositions (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)

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Cited By (2)

Citations (7)

• 2007
  • 2007-11-13 IT IT000588A patent/ITRM20070588A1/it unknown
• 2008
  • 2008-10-30 WO PCT/IT2008/000672 patent/WO2009063520A1/en not_active Ceased

Patent Citations (7)

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