ES2527555B1 - Method and system for spectral reconstruction of standardized light sources - Google Patents

Abstract

Method and system for spectral reconstruction of standardized light sources. # It comprises providing a plurality of electro-optical light sources, selecting a color temperature and / or a color performance value from a plurality of points of the target light spectrum; calculating a luminous flux, a color temperature and a color yield resulting from said electro-optical light sources and providing by a combination of said sources an optimized level of illumination, said electro-optical sources (10) being quasi-monochromatic light and being individually controlled for an adjustment of the quasi-monochromatic spectrum generated (21) by each of them, taking into account said color temperature and said color performance value of the target light spectrum (20).

Description

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DESCRIPTION

Method and system for spectral reconstruction of standardized light sources.

Field of the invention

The present invention refers in a first aspect to a method of tunable and high colorimetric spectral reconstruction of continuous spectrum light sources from a plurality of quasi-monochromatic electro-optic light sources.

The invention also provides a system for the optimization of specific (individual) intensities in a luminaire (matrix) composed of a set of quasi-monochromatic light sources in particular constituted for example by monochromatic LEDs, although capable of being implemented with any type of electro-optical light source, to spectrally and colorimetrically adjust standardized continuous spectrum light sources (average light, other phases of sunlight, illuminators E, A, F2, F11, etc.).

State of the art

A way of innovation towards the modulation of the spectral and colorimetric quality of artificial light sources has been obtained by the combination of technologies, such as conventional luminescence with that of LEDs (WO 2010/0110682), or the doping or variation in the Chemical composition of electroluminescent materials with new compounds, even in very small proportions, to achieve spectral variations of light emission (WO 03/019072; WO 2009/117286; WO 2011/062915). Other recent innovations, in addition, have focused on the real-time measurement of incident light on the scene or human activity, even in combination with the existing ambient light, to modulate in real time the light emission of luminaries based on LEDs or related technologies (WO 2006/0018118; WO 2012/092956).

The pace of innovation in electro-optic luminaires, especially those based on a set of LEDs, or multi-LEDs, has been very high in recent years, although many of these luminaires have focused on specific designs and optimized for safe individual control. , electronic and digital of the set, such as the inventions described in patent documents EP2187112, US20040245946, WO2006062047, US20070229042, WO2007062662, WO2009109387, US20110062873, WO2011113950.

Other inventions have been based on the geometric design, or the flat or three-dimensional arrangement of the electro-optic emitters, such as those described in patents FR2640791 and WO9910867, to more intelligently spread the light emitted by the whole set or system of light sources individual.

For the aforementioned with the advance of electro-optical light emission technologies, whether quasi-monochromatic or not, multi-LED devices or systems, or based on an optimal set of LEDs applied to the tunable natural light spectral adjustment or standardized by The CIE is a clear and profitable research and innovation commitment.

An attractive scientific and technological variant is the selection and design of a LED luminaire based exclusively on colored or quasi-monochromatic LEDs, and not only three or of the RGB type (US 2004/0245946; WO 2006/0018118), as required minimally for the additive mixture of lights for human chromatic perception, but a much wider set, which covers at least homogeneously the visible spectrum, from 400 to 700 nm.

Patents WO2006062047 and US20110062873 describe proposals to simulate or reproduce reference light spectra with high quality, with the help of a set of LED light sources or LEDs operating in groups. Other proposals

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Similar are described in documents US7710369, US8436556, and US7972028, which use different methods to generate a spectrum equivalent to a given illuminant, in particular sunlight, and to optimize a combination of LED light sources operating in groups.

Therefore, there is currently a clear scientific and technological challenge to produce light artificially with new or current technologies with an energy balance and lighting quality that is optimal for replicating the natural light at which the spectral and colorimetric requirement has been maximized. specially adapted the human visual system.

The present invention provides a method and system for the reconstruction or spectral replication of standardized light sources, all of continuous spectrum, from a numerous, but variable, set of electro-optic, quasi-monochromatic light sources. In particular, the invention allows the application of colored LEDs as sources of light, with spectral emission peaks homogeneously covering from 400 to 700 nm or even higher and / or lower ranges, including ultraviolet and near infrared light.

Brief exposition of the invention

For this purpose, the invention provides a method for spectral reconstruction of standardized light sources for high spectral and colorimetric illumination useful in multiple applications, said standardized sources being continuous spectrum, comprising according to known techniques, partly collected in the background above. referred the following stages

- provide a plurality of electro-optic light sources, in particular LED technology;

- select a color temperature and / or a color performance value of a plurality of points of the target light spectrum; Y

- calculate a resulting luminous flux, a color temperature and a color yield from said electro-optical light sources to reproduce the spectrum to be reconstructed;

- provide by a combination of said electro-optic sources an optimized illumination level taking into account said selected color temperature and color performance;

According to the proposal of this invention, the aforementioned electro-optic light sources are quasi-monochromatic and together cover the band of the target light spectrum to be reproduced which is within a range of wavelengths that includes totally or partially at least one of the following light spectra: visible, ultraviolet and near infrared. In addition, said quasi-monochromatic electro-optic light sources are individually controlled for an adjustment of the quasi-monochromatic spectrum generated by each of them, taking into account said color temperature and said color performance value of the target light spectrum. According to this invention, the said individual control of said electro-optical sources of quasi-monochromatic light additionally comprises a control of each electro-optic source at the photometric level, that is to say in relation to the radiated light power.

The said individual control of said quasi-monochromatic electro-optic light sources is performed electronically and digitally and is calculated integrally and simultaneously with the rest of the electro-optic sources used to reproduce the target light spectrum constituting a unique characteristic vector.

The spectrum of target light to be reproduced is covered according to the invention with overlapping by the different quasi-monochromatic individual electro-optic sources used.

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The invention also provides a system for spectral reconstruction of standardized light sources, of continuous spectrum comprising a plurality of electro-optic light sources, in particular LED technology and which according to the invention are quasi-monochromatic and together cover the spectrum of objective light and a control device which individually controls each of said electro-optic sources of quasi-monochromatic light, whereby the method explained above is put into practice.

According to an example of realization of the invention said electro-optic light sources comprise a set of 31 quasi-monochromatic LEDs covering the entire visible range, from 400 to 700 nm, expandable or reducible in number.

According to an embodiment of the invention said plurality of electro-optical sources of quasi-monochromatic light are arranged in a symmetric matrix and on a flat or three-dimensional surface that can adopt various geometries.

The control device implements an algorithm that allows calculating, given the quantity and individual characteristics of the quasi-monochromatic electro-optic emitters available in the matrix, the necessary dominant power and wavelength adjustments of each of them, and their distribution by the matrix , in order to achieve the target light spectrum, and that this is homogeneous.

Description of the figures

The above and other features and advantages will be more evident from the following detailed description of an example of realization with reference to the attached drawings, in which:

Fig. 1 shows the spectral distribution of a set of quasi-monochromatic LEDs, considering their normalized spectral radiance;

Fig. 2 shows six comparative graphs of six spectra of standard light or standard illuminants (dashed line) and the corresponding six spectra of light generated (solid line) by the light source constituted by a matrix of 31 LEDs, reproducing their qualities ;

Fig. 3 shows three graphs of the spectrum of light generated (solid lmea) by means of the luminaire object of the present invention, in comparison with an objective light spectrum (dashed lumen) of the Illuminating type D65, showing three different levels of luminance;

Fig. 4 shows the spectral distribution of the LEDs used considering their absolute spectral radiance;

Fig. 5 shows six comparative graphs of six spectra of standard light or standard illuminants (dashed line) and the corresponding six spectra of light generated (solid line) by the light source constituted by a matrix of 29 LEDs, reproducing their qualities ;

Fig. 6 shows six comparative graphs of six spectra of standard light or standard illuminants (dashed line) and the corresponding six spectra of light generated (solid line) by the light source constituted by a matrix of 23 LEDs, reproducing their qualities ; Y

Fig. 7 shows an example of realization with a matrix of 62 LEDs, which would provide up to 31 dominant wavelengths, connected to a control and switching board of the type used as a luminaire control device.

Detailed description of an example of realization

The present invention has a plurality of electro-optic sources 10 of quasi light

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monochromatic arranged in a matrix 11, according to an example of realization, will consist of thirty-one LED light emitters arranged in a regular matrix 11, as shown in Fig. 7. Said electro-optic sources 10 of quasi-monochromatic light are connected to a control device 30 (Fig. 7) such that said control device 30 can individually regulate the quasi-monochromatic spectrum generated 21 by each of said quasi-monochromatic light sources 10.

Said individual control of each electro-optic source 10 of quasi-monochromatic light is carried out by means of a mathematical algorithm, known per se, which aims to minimize the differences between said values of color temperature and color performance generated by each of the electro-optic sources 10 of quasi-monochromatic light or a set of said sources covering a certain strip or region of the target light spectrum 20. In this way it is possible to differentiate between the quality of the spectral reproduction of two light sources, each comprising several LED sources different.

Thus, using said algorithm, the objective or merit function to be minimized is mathematically constructed by calculating the individual intensity of each of said electro-optic sources 10 of quasi-monochromatic light, in line with the rest of the electro-optic sources 10 of matrix 11 to replicate, by joint emission, a standardized objective light spectrum 20, always of a more or less broad continuous spectrum, and of concrete profile, preferably being able to be within the visible band of 400 to 700 nm, but also being able to be in the ultraviolet light band and / or near infrared, according to another example of realization.

This algorithm for the integral calculation of the individual intensities of each electrooptic light source 10 differs from previous proposals disclosed (Fryc, et al., 2005; Mackiewicz, et al., 2012), and allows evaluating the goodness of the set of electro-optic sources. 10 individual to reconstruct one or the other spectrum of objective light 20, and therefore the level of spectral quality (Imai, Rosen, Berns, 2002) and colorimetric (ClE 2007) of the spectrum of light generated 22 by the set of integrated electro-optical sources 10 inside the matrix 11 forming the luminaire 12.

The proposed spectral reconstruction method can be schematized in the following stages:

divide the target light spectrum 20 to be reconstructed into quasi-monochromatic wavelength fractions, and assign an objective power to each of those fractions;

assign at least one of said individual quasi-monochromatic light sources 10 to each of said fractions, regulating it (by electronic and digital control) individually (both photometrically and colorimetrically) to emit at the wavelength dominant assigned to said fraction;

adjusting by said individual control of said plurality of quasi-monochromatic light sources 10 of the light spectrum 22 so that the total emission power is equal to or less than the sum of the maximum emission power of the quasi light light sources 10 monochromatic individual emitters, so that after said adjustment the generated light spectrum 22 maintains a color temperature and color performance as close as possible to the target light spectrum 20, and

control the power of each electro-optic source 10 of quasi-monochromatic light at the individual level so that the sum of the emission power of all the individual electro-optic sources 10 emitting with the same dominant length is equal to the target power assigned to said fraction .

A description of the mathematical procedure is then carried out

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implemented to know the necessary individual settings of each of the electro-optic sources 10 to obtain a spectrum of generated light 22 that reproduces the target light spectrum 20.

The principle of additive mixing of lights, and therefore of perceived color, is applicable at the colorimetric level, with only the XYZ triestlmulo values of the individual sources or colors of the mixture, and at the spectral level, with the individual contributions of the spectral radiations Le (A,), in W / srm2, the individual intensity levels (electronically and digitally controlled) of each element must be used integrally, both colorimetrically and spectrally, since they act as individual and independent modulating levels within of the entire luminaire 12.

Therefore, although at the computational level it is easier to work at the algorithmic level with triestlmulo XYZ values of the individual lights (Ries, et al., 2004; Lin, 2010), this does not always guarantee the highest colorimetric quality (Tc and Ra), far from the maximum spectral quality or perfect reconstruction. Although a broad set of n individual electro-optic sources 10 is selected, covering ranges of wavelengths of 10 or 20 nm from 400 to 700 nm, the mixing of lights at the radiometric level implies establishing a set of M simultaneous linear equations with n (contribution individual or weight) unknowns, where n << M. From here, the mathematical solution of the characteristic vector p (p1, p2, ..., pn) can be raised with conventional methods, but must simultaneously meet several requirements, conditions or ligatures, so that the solution can be feasible or realizable at the physical level.

The main requirement or radiometric feasibility is that the individual intensities must be between 0 and 1 simultaneously (that is, always positive) for the whole set of n quasi-monochromatic light sources 10, although each one has a starting level specific radiance or total luminance.

From here, the target light spectrum 20 to be reconstructed is selected, an illumination level (in lx) attainable with the spectral and photometric sum of the set of electro-optic sources 10 integrated within the matrix 11 must be selected. With these conditions, the objective or merit function to be minimized is constructed mathematically, including simultaneously all the M equations to obtain a single solution p (p1, p2, ..., pn) possible, and physically verifiable.

Depending on the merit function to be minimized, and of the set of n electro-optic sources 10 of quasi-monochromatic light available, its radiometric power, and the degree of spectral sampling (M), the goodness or level of spectral and colorimetric quality can vary dramatically .

The proposal described here differs from other applications such as Fryc et al. (2005) and Mackiewicz, et al. (2012) in the function of merit to be minimized, which has been considered key, and obviously of luminaire 12, but also the dynamic range of digital variation of individual contribution of each of the said electro-optic sources 10, from at least 0 to 100, in steps of 1 in 1, and radiometrically measurable.

In the present invention, depending on the objective light spectrum 20 to be reconstructed, several physically possible solutions can be provided, and with different levels of illumination (in lx), and always with the same spectral and colorimetric quality, as shown in the Fig. 3.

On the other hand, this same methodology set forth in this invention allows the individual importance or relevance of each individual light source 10 for each type of objective light spectrum 20 to be evaluated.

According to another example of realization, some electro-optical light sources 10 can be integrated

that are not quasi-monochromic within the matrix, or some of the electro-optic sources 10 can be configured to emit non-monochromatic light, even white light sources can be used. Said white light sources would be integrated, together with the electro-optic sources 10 of quasi-monochromatic light, in the same manner described above, and with the same objective, so that each of said electro-optic sources 10 of non-monochromatic light could simultaneously emit in a plurality of wavelengths and, together with the light emitted by the electro-optical sources 10 of quasi-monochromatic light, also obtain a spectrum of generated light 22 equal to or close to the target light spectrum 20 to be reconstructed.

10 The proposed method can be characterized in that said individual control of each electro-optical source 10 of quasi-monochromatic light is carried out by means of an algorithm that minimizes the differences between said color temperature and color performance values generated by each of the electro-optic sources 10 of quasi-monochromatic light or by a set of said sources that covers a certain strip or region of the target light spectrum 20.

Alternatively, or in addition said proposed method can be characterized in that the set of said electro-optic sources 10 of quasi-monochromatic light are arranged in a matrix 11, so that at a distance greater than the distance necessary for the space-visual integration to occur, the radiometric spectrum measurement that covers the entire matrix 11 corresponds to the spectrum of light generated 22 by the sum of the emissions from the sources

20 electro-optic 10 of quasi-monochromatic individual light, which resembles the target light spectrum 20.

The method can also be characterized in that said matrix 11 of light sources 10 is symmetrical.

REFERENCES

Michal Mackiewicz, Stuart Crichton, Steve Newsome, et al: "Spectrally tunable LED illuminator for vision research". Proceeding of CGIV (Color on Graphics, Imaging and Vision 2012), 372377 (2012).

5 I Fryc, S.W. Brown, Y Ohno: "Spectral matching with an LED-based spectrally tunable light source". Proc. SPIE (Fifth International Conference on Solid State Lighting), 5941, 59411-9 (2005).

F.H. Imai, M.R. Rosen, R.S. Berns: "Comparative study of metrics for spectral match quality". Proc. CGIV (European Conference on Color Graphics, Imaging and Vision), 1, 492-496 (2002).

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Claims (18)

5 10 fifteen twenty 25 30 35 40 1.- Method for spectral reconstruction of standardized light sources for high-quality spectral and colorimetric illumination in multiple applications, said standardized sources of continuous spectrum light, and said method being applied to a system with a plurality of electro-optic light sources and with a control device, comprising: - select a color temperature and / or a color performance value of a plurality of points of a target light spectrum to be reconstructed with electro-optic light sources; - calculate a luminous flux and a resulting color temperature and color performance, from a combination of said electro-optic light sources, to reproduce the target light spectrum to be reconstructed; - providing, by a combination of said electro-optic sources, an optimized illumination level taking into account said selected color temperature and / or color performance; characterized in that it comprises: divide the target light spectrum (20) to be reconstructed into quasi-monochromatic wavelength fractions, and assign an objective power to each of those fractions; assign at least one of said electro-optic sources (10) of quasi-monochromatic light, individual, to each of said fractions, regulating it so that it emits in the dominant wavelength assigned to said fraction; and because: said electro-optic light sources (10) are quasi-monochromatic and together cover the band of the target light spectrum (20) to be reproduced; Y said electro-optic sources (10) of quasi-monochromatic light are individually controlled for an adjustment of the quasi-monochromatic spectrum generated (21) by each of them, taking into account said color temperature and said color performance value of the target light spectrum ( twenty). 2. - Method according to revindication 1, characterized in that said individual control of said electro-optic sources (10) of quasi-monochromatic light additionally comprises a control of each electro-optic source (10) at the photometric level. 3. - Method according to revindication 1, characterized in that said objective light spectrum (20) is overlapped by the different electro-optic sources (10) quasi-monochromatic individual used. 4. - Method according to any one of the preceding claims characterized in that the target light spectrum (20) is within a range of wavelengths that includes totally or partially at least one of the following light spectra: visible, ultraviolet and near infrared 5. - Method according to revindication 1, characterized in that said electro-optic sources (10) of quasi-monochromatic light are based on LED technology. 6. - Method according to revindication 1, characterized in that the individual control of each electro-optical source (10) of quasi-monochromatic light is calculated integrally and 5 10 fifteen twenty 25 30 35 40 Simultaneously with the rest of electro-optic sources (10) used to reproduce the target light spectrum (20), constituting a unique characteristic vector. 7. - Method according to claim 1 or 6, characterized in that said individual control of said electro-optic sources (10) of quasi-monochromatic light is carried out electronically and digitally. 8. - Method according to claim 1 or 6, characterized in that it comprises: adjust by said individual control of said plurality of electro-optic sources (10) of quasi-monochromatic light the spectrum of generated light (22) so that the total emission power is equal to or less than the sum of the maximum emission power of the electro-optic sources (10) of quasi-monochromatic individual emitting light, so that after said adjustment the generated light spectrum (22) maintains a color temperature and color performance as close as possible to the target light spectrum (20), and control the power of each electro-optical source (10) of quasi-monochromatic light at the individual level so that the sum of the emission power of all the individual sources emitting with the same dominant length is equal to the target power assigned to said fraction . 9. - Method according to claim 8 characterized in that some individual emitting light sources that emit white light are additionally provided, simultaneously assigning several quasi monochromatic fractions of the spectrum of different wavelengths. 10. - Method according to claim 1 or 6 characterized in that a differentiated control is carried out at certain intervals of wavelengths of the target light spectrum (20). 11. - Method according to claim 10, characterized in that one of said individualized wavelength ranges comprises a range of wavelengths between 400 and 550 nm. 12. - Method according to claim 6, characterized in that said individual control of each electro-optical source (10) of quasi-monochromatic light is carried out by means of an algorithm that minimizes the differences between said values of color temperature and color yield generated by each of the electro-optic sources (10) of quasi-monochromatic light or by a set of said sources covering a certain strip or region of the target light spectrum (20). 13. - Method according to any one of the preceding claims characterized in that the set of said electro-optical sources (10) of quasi-monochromatic light are arranged in a matrix (11), so that at a distance greater than the distance necessary for it to occur space-visual integration, the radiometric spectrum measurement that covers the entire matrix (11) corresponds to the spectrum of light generated (22) by the sum of the emissions of the electro-optic sources (10) of quasi-monochromatic individual light, which resembles the spectrum of objective light (20). 14. - Method according to claim 13, characterized in that said matrix (11) of electro-optic light sources (10) is symmetrical. 15. - Method according to claim 5, characterized in that it comprises a set of 31 quasi-monochromatic LEDs covering the entire visible range, from 400 to 700 nm, expandable or reducible in number. 10 fifteen 16. - System for spectral reconstruction of standardized light sources, for illumination, said standardized sources being of continuous spectrum, of the type comprising: a plurality of electro-optic sources (10) of light; a control device (30), characterized in that: - said electro-optic light sources (10) are quasi-monochromatic and together cover the target light spectrum (20); Y - said control device (30) individually controls each of said electro-optic sources (10) of light, quasi-monochromatic, implementing the method described in any one of the preceding claims. 17. - System, according to revindication 16, characterized in that said plurality of electro-optic sources (10) of quasi-monochromatic light are arranged in a symmetrical matrix (11) and on a flat or three-dimensional surface. 18. - System according to revindication 16 or 17, characterized in that it comprises a set of 31 quasi monochromatic LEDs (10) covering the entire visible range, from 400 to 700 nm, expandable or reducible in number.