3D Concentrator

Abstract

at least one light emitting module (ME), a luminescent crystalline lens having at least six pairs of parallel faces, known as concentrator crystal (CL), including first and second faces, known as side faces (FL1, FL2), perpendicular to the direction x and separated by a distance L corresponding to the horizontal dimension of said concentrator in the direction x; a first mirror (M1) configured to at least partially cover said first side surface (FL1) and to define a surface area (SR1) covered by said first mirror and at least one surface area (SFS1) not covered by said first mirror that defines an associated output surface (FS1, FS11, FS12); a second mirror (M2) configured to cover at least 95% of said second side surface (FL2); a light emitting module (ME) including: - the luminance radiation (L F a brightness triggering element (ED) designed to generate an emission of Including, The uncovered surface area (SFS1) and the surface area of ​​the first side (FL1) (S L ) is the ratio R of the luminance radiation reflected by the first and second mirrors over an average distance L moy and propagates through at least one output face (FS11, FS12) within the luminescent crystal to form an output beam (L out ) before forming TIFF2023533026000007.tif14170, and α is the loss factor per unit length of the concentrator for the luminance radiation. Light-emitting device (1).

Description

[Technical Field]

[0001] This invention relates to a luminescent concentrator excited by a light-emitting diode (LED), and more specifically, to a luminescent concentrator excited by an LED used as a light source. [Background technology]

[0002] Light-emitting diodes (LEDs) have many applications in the field of lighting. However, the brightness of LEDs is limited to values ​​that are not suitable for certain applications.

[0003] A solution to increase the brightness of LEDs is to use light-emitting diode pumped luminescent concentrators (see, for example, Barbet, Adrien, et al. “Light-emitting diode pumped luminescent concentrators: a new opportunity for low-cost solid-state lasers.” Optica 3.5(2016):465-468). These concentrators are crystals that emit visible spectrum (red-orange) fluorescence, such as Ce:YAG, which absorb the blue spectrum (approximately 450 nm) at wavelengths where LEDs exhibit very high performance. The crystals are cut into planar forms, which are integrated with hundreds (or even thousands) of LEDs on two large surfaces, causing them to emit light in cross-section. These concentrators make it possible to obtain brightness 10 to 20 times higher than that of LEDs alone.

[0004] Figures 1A and 1B show an example of a light-emitting module ME0 based on a concentrator crystal CL, as known in the industry. Figures 1A and 1B represent schematic views of the same light-emitting module ME0, in perspective and in the side, respectively. The light-emitting module ME0 includes a group of LEDs designed to emit light in a first spectral band and a light concentrator CL. The concentrator CL is a fluorescent rectangular crystalline body having at least one illumination surface SI1, SI2 with dimensions L × w, which emits light L from the LEDs. d It is illuminated by [a specific method / function]. The illumination surfaces SI1 and SI2 are also known as "large faces". The thickness of the concentrator is known as e.

[0005] The crystal of the concentrator emits light L d It is configured to absorb light. The stream of light emitted by the LED and directed toward the illuminated surface is absorbed by the Lum luminescent group of the fluorescent crystal, and these are dispersed throughout the entire volume of the crystal, thus emitting fluorescence within the crystal. The emitted light rays can be classified into two main categories: namely, -L p Trapped rays, also known as reticular rays, are trapped within the crystal as a result of total intracellular reflection (RTI) across different faces of the crystal. These rays exist when the crystal is a cuboid, providing six faces that are parallel in pairs and perpendicular to each other. Trapped rays never escape the crystal, except in the case of imperfections. -Untrapped rays are the rays that are last emitted from the crystal. These are characterized by being guided by total internal reflection, L g The guide ray, known as L, is emitted directly from the concentrator without reflection from the surface. out These are classified as non-guided rays, also known as guiding rays.

[0006] Figure 1C is a representation of the angular diagram of light rays emitted and captured by the concentrator. The dark spherical cap area represents the angles corresponding to uncaptured (guided and unguided) rays, and the bright area represents the angles corresponding to captured rays. In this representation provided as an example, the medium selected as the concentrator crystal CL is a Ce:YAG crystal (refractive index n² = 1.82), and the critical angle when the environmental medium is air is 33°. The percentage of radiation captured by total internal reflection compared to uncaptured radiation is determined by the refractive index of the crystal and the environmental medium according to the Snell-Cartes law.

[0007] In prior art concentrators, such as those shown in Figures 1A-1C, illumination of the output surface is proportional to the ratio L / e of the length to thickness of the concentrator crystal. Generally, the L / e ratio of concentrators is very high (e.g., L=100mm, e=1mm, L / e=100). Therefore, the number of reflections on the two large surfaces SI1 and SI2 is high, i.e., about 100 times for a ray propagating at an angle of 20-30° with L=100mm. On the other hand, it is much lower on the sides. Figures 1D and 1E show the refractive index n=1.82 (limiting angle θ) on two planes, i.e., planes parallel (xy) and perpendicular (xz) to the large surfaces. crit This compares the difference in the number of light ray reflections at the total internal reflection limit within a concentrator crystal at an angle of 33°. In the plane (xy) of the larger surface, the number of reflections is related to the width w of the concentrator. Figure 1D represents a concentrator with width w >> e. In this case, the focusing effect occurs on one plane (xz) perpendicular to the larger surface, and this type of focusing is defined in this case as "1D focusing". "1D" focusing is used in large luminescent concentrators in the field of solar concentrators (see, for example, Meinardi, Francesco, et al. "Large-area luminescent solar concentrators based on 'Stokes-shift-engineered' nanocrystals in a mass-polymerized PMMA matrix." Nature Photonics 8.5(2014):392).

[0008] Figure 1E represents a concentrator with a width w approximately equal to its thickness e. In this case, the focusing effect occurs on two planes (xz) and (xy), i.e., reflections on the four sides of the concentrator are utilized. This type of focusing is defined in this context as "2D" focusing. This configuration is often used in concentrators excited by LEDs (see, for example, DKGde Boer, D. Bruls, and H. Jagt, "High-brightness sources based on luminescent concentration," Optics Express, vol. 24, no. 14, page A1069, July 2016). One drawback of this 2D focusing is that the surface area of ​​the illuminated surface is small, thereby limiting the excitation power of the concentrator and, consequently, its output power.

[0009] In "1D" and "2D" focusing, the output brightness of materials with fixed L and e values ​​will be the same. In fact, the brightness does not depend on w, but only on the L / e ratio.

[0010] While the illumination increase provided by concentrators is significantly greater compared to LEDs, the illumination is still lower compared to illumination provided by, for example, laser diodes. In addition, the waveform of the output beam depends on the shape of the concentrator (generally, the output surface is oval). Finally, in prior art fluorescence concentrators, the thickness e must be greater than the absorption length associated with the excitation emission so that the power absorbed in a low-absorption environment for "1D" or "2D" focusing is maximized. [Prior art documents] [Non-patent literature]

[0011] [Non-Patent Document 1] Barbet, Adrien, et al. “Light-emitting diode pumped luminescent concentrators: a new opportunity for low-cost solid-state lasers.” Optica 3.5 (2016): 465-468 [Non-Patent Document 2] Meinardi, Francesco, etal. “Large-area luminescent solar concentrators based on'Stokes-shift-engineered'nanocrystals in a mass-polymerized PMMA matrix.”Nature Photonics 8.5(2014):392 [Non-Patent Document 3] DKGde Boer,D.Bruls,and H.Jagt“High-brightness sources based on luminescent concentration”Optics Express,vol.24,no.14,page A1069,July 2016 [Overview of the project] [Problems that the invention aims to solve]

[0012] The objective of the present invention is to increase the output brightness of the concentrator while providing flexibility in the parameters of the output beam and the specifications (dimensions, loss, absorption) of the concentrator material. [Means for solving the problem]

[0013] For this purpose, the gist of the present invention is, - At least one light-emitting module, - A luminescent crystal having at least six pairs of parallel faces, including first and second faces known as concentrator crystal faces that are perpendicular to the direction x and separated by a distance L corresponding to the horizontal dimension of the concentrator in the direction x. - A first mirror configured to at least partially cover the first side face, defining a surface region covered by the first mirror and at least one surface region not covered by the first mirror that defines an associated output face. - A second mirror configured to cover at least 95% of the second side face. A light-emitting module including: - A luminance triggering element designed to generate the emission of luminance radiation within the luminescent crystal. Including: The ratio R of the non-covered surface region to the surface region of the first side face is such that the light rays of the luminance radiation are reflected by the first and second mirrors and propagate over an average distance L moy before passing through at least one output face within the luminescent crystal to form an output beam.

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[0014] According to a specific embodiment of the present invention, - The ratio R is 1 / 4 or less, preferably 1 / 8 or less. - The loss coefficient α per unit length of the concentrator with respect to the luminance radiation and the ratio R are designed such that L moy <L p = 1 / α. - The luminance triggering element has a wavelength λ dThe system includes a plurality of light-emitting diodes or lasers or flash lamps configured to emit light emission, wherein the diodes are designed to illuminate at least one surface known as the illumination surface of a concentrator, and the concentrator is a fluorescent crystal designed to absorb the light emission and then emit fluorescent emission corresponding to the luminance emission. - The vertical dimension e of the concentrator in the direction z perpendicular to the illumination surface is the absorption length L of the luminescent radiation by the concentrator. abs Greater than or equal to, - The luminance triggering element includes a heating element configured to heat the concentrator crystal so that it emits luminance radiation by thermal emission, - The luminance triggering element includes a lens, which is designed to focus sunlight onto the so-called illuminating surface of a concentrator, and the concentrator is designed to absorb the sunlight and then emit fluorescence corresponding to the luminance emission. - The concentrator crystal has a chamfered edge between the first side surface and the other surface of the concentrator crystal, and the surface area of ​​the chamfered edge is considered to be part of the surface area of ​​the first side surface in the calculation of the ratio R, and at least a portion of the surface area of ​​the chamfered edge is not covered, defining the relevant output surface, - The concentrator crystal has a chamfered corner between the first side surface and the other two faces of the concentrator crystal, and the surface area of ​​the chamfered corner is considered to be part of the surface area of ​​the first side surface in the calculation of the ratio R, and at least a portion of the surface area of ​​the chamfered corner is not covered, defining the associated output surface, - The first mirror is designed to define n ≥ 1 uncovered surface areas, defining n output surfaces through which n output beams pass, and the apparatus also, -n optical fibers, -n optical coupling systems, each designed to combine output beams in different optical fibers. This also includes, - The first mirror is designed such that the geometric range of each output beam is substantially equal to the geometric range of the optical fiber that couples the output beams. - The device includes two additional mirrors that cover two parallel surfaces known as the cross-section of the concentrator, the two additional mirrors being designed to cover the entire cross-section, - The apparatus includes first and second light-emitting modules and a luminance triggering element associated with the first light-emitting module, wherein a side of the concentrator crystal of the second light-emitting module, different from the side surface, is attached to the output surface of the concentrator crystal of the first light-emitting module, thereby the first output beam of the first light-emitting module, known as the primary luminance emission, constitutes the luminance triggering element of the second light-emitting module, and the second light-emitting module generates a second output beam, known as the secondary luminance emission, whose center wavelength is shifted with respect to the center wavelength of the primary luminance emission. - The dimensions of the second module on the vertical plane yz parallel to the output surface of the concentrator crystal of the first module are smaller than or equal to the dimensions of the output surface of the concentrator of the first light-emitting module. - The dimension of the second module concentrator in direction x is the absorption length L of the primary luminance radiation by the second module concentrator. abs.2 Larger, - The first mirror is mounted on a translation system designed to displace the first mirror with respect to the first side surface, thereby increasing or decreasing the uncovered surface area. - The first mirror is designed such that the shape of the uncovered surface area is square, rectangular, circular, oval, triangular, or polygonal.

[0015] Other features, details, and advantages of the present invention are provided as examples and will become apparent from the description provided with respect to the accompanying drawings, which represent the following, respectively. [Brief explanation of the drawing]

[0016] [Figure 1A]A schematic diagram of an example of a light-emitting module known in the prior art is shown. [Figure 1B] A schematic diagram of an example of a light-emitting module known in the prior art is shown. [Figure 1C] A schematic diagram of an example of a light-emitting module known in the prior art is shown. [Figure 1D] A schematic diagram of a concentrator known from prior art is shown. [Figure 1E] A schematic diagram of a concentrator known from prior art is shown. [Figure 2] A schematic diagram of the light-emitting device according to the present invention is shown. [Figure 3A] This shows a schematic representation of the movement of light rays in fluorescent radiation. [Figure 3B] This shows a schematic representation of the movement of light rays in fluorescent radiation. [Figure 4] Two transmittance curves corresponding to the emission angle of the fluorescent light are shown. [Figure 5A] This shows the average transmittance corresponding to the dimensions s of the output surface. [Figure 5B] This shows the change in the ratio E / Eref according to the dimensions s of the output surface. [Figure 5C] This shows the change in average length according to the dimension s of the output surface. [Figure 6A] Each shows the change in the average equivalent tail ratio Tmoy and the ratio E / Eref depending on the output surface dimension s for different loss coefficient values. [Figure 6B] Each shows the change in the average equivalent tail ratio Tmoy and the ratio E / Eref depending on the output surface dimension s for different loss coefficient values. [Figure 7A] This shows the changes in the ratios E / Eref and Lmoy / Lp depending on the output surface dimension s for two different loss coefficient values. [Figure 7B] This shows the changes in the ratios E / Eref and Lmoy / Lp depending on the output surface dimension s for two different loss coefficient values. [Figure 8] An embodiment of the present invention is shown in which the concentrator crystal is cubic. [Figure 9]This shows the change in output power Pout and illumination E of the output beam according to the surface area of ​​the output surface. [Figure 10A] The apparatus according to an embodiment of the present invention is shown, in which the first mirror is designed such that the shapes of the uncovered surface areas are a disk and the letter "A", respectively. [Figure 10B] The apparatus according to an embodiment of the present invention is shown, in which the first mirror is designed such that the shapes of the uncovered surface areas are a disk and the letter "A", respectively. [Figure 11] This shows an embodiment in which the concentrator crystal has a chamfered edge. [Figure 12] An embodiment in which the first mirror is attached to the translational system is shown. [Figure 13A] This describes an embodiment in which multiple fiber bearing outputs are coupled in the form of a fiber group. [Figure 13B] This shows the change in coupled power Pc in an optical fiber according to the surface area of ​​the output surface. [Figure 14] This document illustrates an embodiment of the present invention in which the apparatus includes first and second light-emitting modules. [Modes for carrying out the invention]

[0017] Unless otherwise noted, the elements in the diagrams are not depicted to an exact scale.

[0018] Figure 2 shows a schematic diagram of a light-emitting device 1 according to the present invention. The device includes a light-emitting module ME which includes a so-called concentrator light-emitting crystal CL. This concentrator crystal includes six parallel faces, two of each, including first and second faces known as sides FL1 and FL2, with dimensions w × e. These sides are perpendicular to direction x and separated by a distance L (called length) corresponding to the horizontal dimension of the concentrator in direction x, where L is the largest dimension of the concentrator. Faces SI1 and SI2 with dimensions L × w are called "large faces" or "illumination faces," and the face with dimensions L × e is called a "section."

[0019] Device 1 emits luminance L within a light-emitting crystal.F This includes a luminance triggering element ED designed to generate light emission. As will be detailed later, the luminance triggering element can be multiple LEDs, one or more optical elements designed to direct sunlight towards the concentrator, or an element designed to heat the concentrator.

[0020] Unlike the aforementioned concentrators 1D and 2D, the object of the present invention is to obtain a supplemental focusing effect in order to enhance the brightness obtained from the output of the concentrator. This focusing effect is known as 3D because the radiation is focused into the crystal, across its entire surface. For this purpose, apparatus 1 includes two mirrors M1 and M2, which are designed to produce a supplemental focusing effect on the side plane (xy) in addition to the focusing effect obtained on the large surface plane (xz) (and optionally on the cross-sectional plane (xy) corresponding to the width w of the concentrator). Therefore, reflection on the side can be increased before the luminance radiation rays "emit" from the concentrator, thereby achieving an enhancement of illumination and brightness on the output surface due to the effect of the rays being folded back.

[0021] The first mirror M1 at least partially covers the first side surface FL1, defining a surface area SR1 not covered by the first mirror and at least one surface area SFS1 that defines the associated output surface FS1, which is not covered by the first mirror. For this purpose, the first mirror M1 is positioned opposite the first side surface FL1, mounted on it, or deposited on it. After numerous simulations, the inventors found, as will be described later, that the ratio of the surface area of ​​the output surface to that of the first side surface is an important parameter for ensuring a light-gathering effect on the side and, consequently, for ensuring enhanced illumination on the output surface. The dimensions of the light-emitting module are defined by the uncovered surface area SFS1 (surface area of ​​the output surface FS1) and the total surface area S of the first side surface. L The ratio R = SFS1 / S L However, the luminance rays are reflected by the first and second mirrors, and on average, they travel over an average distance L within the crystal CL.moy It is designed to propagate over L and then pass through the output surface FS1. The luminance radiation rays emitted from the concentrator are directed to the output beam L. out Forms L mou >>L in this case is L moy This means that it is 7 times, preferably 15 times, larger than L.

[0022] As will be explained in detail later, condition L moy >>The ratio R = SFS1 / S is designed to obtain L. L This ensures that the concentrator effect exists on a 3D plane, meaning that instead of directly passing through the output surface FS1 after generation, the luminance radiation is mostly reflected within the crystal and generally travels back and forth within the crystal many times before being emitted from the output surface FS1. Ratio R = SFS1 / S L The smaller the value, the greater the average distance L traveled within the concentrator before the brightness ray is emitted. moy This lengthens. Therefore, illumination on the output surface is enhanced because there is time for the luminance radiation to "fill" the concentrator before emission. This point is particularly counterintuitive because the ratio of output power with and without mirror M1 is simply the ratio of surface area SFS1 / S L This can be considered equivalent, and this would be true if all the rays were emitted from a single plane. In the present invention, the volume and the effect of multiple reflections within the volume make it possible to obtain greater output power at the output surface FS1. In particular, the inventors have found that when the ratio R is 1 / 4 or less, preferably 1 / 8 or less, the average distance L moy It was found that the module ME is sufficient to provide a concentrator effect as a result (see below). Therefore, according to a preferred embodiment of the present invention, R is 1 / 4 or less, or preferably 1 / 8 or less.

[0023] The second mirror M2 is configured to cover at least 99% of the second side surface FL2 opposite to the first side surface. Preferably, the second mirror M2 covers the entire second side surface.

[0024] Therefore, luminance radiation can only be emitted from the side through the output surface FS1. In fact, mirrors M1 and M2 force the rays that would otherwise be emitted from the side to travel more times within the concentrator, and ultimately they pass through the uncovered surface region, i.e., the output surface FS1. This travel means that they are reflected multiple times on the side within the concentrator. Therefore, illumination of the output beam at the output surface is enhanced by the use of mirrors M1 and M2.

[0025] In the drawing of Figure 2, as a non-limiting example, the output surface is rectangular, and its dimensions are equal to the thickness e of the concentrator in direction z and the dimension s in direction y. Therefore, the dimensions of the output surface are s × e. In this example, the ratio R is therefore equal to the ratio s / w. Alternatively, according to other embodiments, the first mirror is designed such that the shape of the uncovered surface area (and thus the output surface) is also square, rectangular, circular, oval, triangular, or polygonal.

[0026] The reflectance of mirrors M1 and M2 is higher than 95% and preferably higher than 98% for luminance radiation.

[0027] Figure 3B is a schematic representation of the movement of a ray of fluorescent radiation emitted by the Lum luminescent fountain in the plane (xy) of the illumination surface SI1 and the moment it "emits" from the concentrator through the output surface FS1. In this embodiment, the apparatus also includes two additional mirrors M3, M4 (shown in Figure 3A), which are positioned opposite or deposited on the cross section of the concentrator. The two additional mirrors are positioned to cover the entire cross section. These mirrors make it possible to reflect within the concentrator the portion of the luminance reflection that is not guided by total internal reflection and should be emitted from the concentrator through the cross section, thus enhancing illumination at the output surface. According to this embodiment and those of the subsequent drawings, mirror M2 completely covers the second side FL2, thereby maximizing illumination at the output surface. Alternatively, according to other embodiments, mirror M2 does not completely cover the second side FL2.

[0028] In the representation in Figure 3B, the concentrator CL is shown at each reflection rather than showing multiple reflections of the ray, for the sake of clarity in the drawing. Therefore, each individual rectangle (or riposte) represents a concentrator CL. Since all two planes are parallel, the equivalent ray corresponding to the ray reflected by the first and second mirrors propagates linearly in the drawing, including the concentrator and its ripostes with respect to the four mirrors that make up the side. The output surface FS1 is also shown at each riposte. To determine whether the ray actually emits, it is necessary to observe point A where it intersects one of the ripostes of the output surface. In the example in Figure 3B, the ray ultimately emits after four reflections at the cross section and four reflections at the side.

[0029] Each ripost in the output region therefore corresponds to a set of angles that enable ejection.

[0030] By adding up all these angles and considering the loss due to the propagation of luminance radiation within the concentrator CL, it is possible to estimate the average transmittance starting from the light-emitting point within the concentrator for a given angular range.

[0031] Figure 4 shows two transmission curves C1 and C2 corresponding to the output angle of the fluorescence emission ray. The output angle θ is shown with respect to the normal of the output surface on the plane xy. In the example in Figure 4, the dimensions of the concentrator are as follows: L=100mm, w=14mm, e=1mm. These dimensions are shown as examples and are not limiting. According to this embodiment and those in Figures 5A-

[0032] In this case, all conceivable rays are considered, and the incident range through which rays pass the output surface is a maximum of 90°. This case would exist if the concentrator is bonded to an output medium with the same refractive index and the sides have perfect reflectivity for all incident light. When air is the ambient medium surrounding the concentrator, the critical angle θ crit =sin -1 Only rays smaller than (1 / n) must be considered, where n is the refractive index of the concentrator. In the case of a Ce:YAG concentrator, n = 1.82, which corresponds to a maximum output angle of 33°.

[0033] Curves C1 and C2 contain points of very low transmittance, corresponding to rays at angles that hardly pass through the output surface. It should be noted that transmittance has a high "peak" near these points. "Peak" in this case means that the slope of the curve near these points is very steep. As the dimensions of the output surface decrease (curve C2), the number of angles (and therefore rays) corresponding to these low transmittance points increases. In addition, it should be noted that transmittance decreases overall for strong incident light, corresponding to the average propagation distance L of luminance radiation within the structure. moy This is associated with a decrease in the number of reflections from the sides, and therefore an increase in losses due to propagation in the medium. This effect is explained in more detail in Figures 5A to 5B.

[0034] Figure 5A shows the average transmittance in air of all luminance rays (see Figure 4) passing through the output surface FS1, depending on the dimensions s of the output surface. The dimensions are the same as those in the example in Figure 4. In this particular case, the ratio R = SFS1 / S L Therefore, is equal to w / s. The curves in Figures 5A and 5B therefore have an X-axis proportional to R (this is also true for Figures 7A-8B and 10). As already explained, the output angle of the luminance rays is 0-33°. The average transmittance Tmoy remains very high even with a small value of s, thanks to multiple reflections within the concentrator. Therefore, the transmittance is s=1mm (i.e., R=1 / 14) and the loss factor α=3.10 -4 mm-1 (Conventional value for Ce:YAG concentrator) remains at 50%. moy is the average transmittance T moy and mm -1 The following equation applies to the unit loss coefficient α:

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[0035] Figure 5B shows the illumination E on the output surface obtained with the device according to the present invention, corresponding to the dimensions s of the output surface, and the illumination E on the first side surface FL1 obtained in a conventional configuration that does not have mirror M1 but has mirror M2. ref E / E ratio ref This shows the changes. The parameters are the same as those in Figure 5A. In Figure 5B, we can observe that the illumination of the output area increases significantly when its surface area is sufficiently small. When R=1 / 4 (s=3.5mm), the illumination on the output surface increases by more than three times. When R=1 / 8 (s=1.75mm), the illumination on the output surface increases by six times. These values ​​correspond to the concentrator effect that satisfies 3D focusing, thereby achieving an order of magnitude (10 times) increase in illumination. In particular, when the output surface dimensions change from s=14mm;R=1 to s=1mm;R=1 / 14, the illumination increases by eight times. The 3D focusing effect also applies to the juxtaposition of the effects shown in Figures 5A and 5B by finding the point of compromise, i.e., the transmittance that remains at a high level even when the surface area of ​​the output surface is significantly reduced, and the resulting increase in illumination. When the value of s on the output surface is very low, the illumination on the output surface decreases. This effect is superior to the 3D focusing effect and is due to substantial loss caused by the propagation of luminance radiation within the concentrator, thus serving as the lower limit of the ratio R for optimal 3D effect.

[0036] By evaluating the rays reflected at M1 and then at M2 each time they pass through, and considering the rays emitted each time they collide with surface FL1, the average length of travel through the medium is

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[0037] Figures 6A and 6B show different loss coefficient values ​​(curve TS). 10 and E 10 α = 10 -4 mm -1 From curves TS1 and E1, α = 10 -3 mm -1 Average transmittance T depending on the dimensions s of the output surface (up to) moy E / E ratio ref This shows the change. Other parameters are the same as those in Figures 5A and 5B. The increase in loss is due to the average transmittance and illumination at the output surface (ratio E / E). ref It is observed that this has the effect of reducing (and L) due to propagation. p This is due to a reduction in losses (due to a decrease in R), and for small output surface area (small R), L moy As it becomes larger, it becomes stronger. When R=1 / 8 (s=1.75mm), the loss is α=10 -4 mm -1 From α=10 -3 mm -1As a result, the illumination on the output surface increases by 4 to 8 times. As shown in Figure 6B, 10 -3 mm -1 Up to a certain loss (curve E1), the focusing effect on illumination is still visible, but it appears to be a "peak." Therefore, it is important to match the dimensions of the first mirror to the concentrator loss to ensure a 3D focusing effect (see Figures 7A and 7B).

[0038] Figures 7A and 7B show the loss coefficients α = 10, respectively. -3 mm -1 and α=10 -4 mm -1 Alternatively, the ratio E / E corresponding to the dimension s of the output surface for concentrators with Lp=1m and Lp=10m, respectively. ref of, and ratio L moy / L p This represents the change in L. moy This increases as the surface area of ​​the output surface decreases. In fact, each ray must travel along a longer path before it can pass through the output surface. When the loss level is high (Figure 7A), L moy When the surface area of ​​the output surface is very small (s is less than 1.6 mm), L rapidly increases. p It can be seen that it can exceed this. When s is very small, the illumination of the output surface (ratio E / E) ref ) decreases as s decreases, which is due to substantial losses due to propagation in the medium. On the other hand, as the surface area of ​​the output surface increases (when s > 0.3 in Figure 7A), the illumination on the output surface (ratio E / E) ref ) increases as s decreases. When R=1 / 4, the illumination is R=1 (s=14mm) and L moy = 0.5 × L p This represents a 2.75-fold increase compared to 0.5m. moy In this case, it is 5 times L. When R=1 / 8, the illumination is R=1 and L moy =L p = This represents a 3.75-fold increase compared to 1m. moy Therefore, it is 10 times L.

[0039] If the loss is smaller (Figure 7B), even if s is very small, the illumination of the output surface (ratio E / E) ref ) continues to increase as s decreases, but this is L moy is L p This is because it remains lower. In this case, the loss does not outweigh the effect of the concentrator, even for the output surface with a small surface area. When R=1 / 4, the illumination increases fourfold compared to R=1. When R=1 / 8, the illumination increases eightfold compared to R=1. In either case, L moy It is much larger than L, p It remains less than 10m.

[0040] Furthermore, preferably, the ratio R is adjusted with respect to loss. It can be shown that the optimal ratio is R = 2L. Therefore, according to a preferred embodiment of the present invention, the ratio R is R = 2L, thereby achieving the largest possible ratio E / E ref You can obtain this.

[0041] Unlike 1D or 2D focusing, 3D focusing does not depend on the shape factor L / e. In fact, in the apparatus according to the present invention, illumination on the output surface is

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[0042] According to one embodiment, the concentrator is a fluorescent crystal. According to a first variation of this embodiment, similar to the apparatus in Figures 1A and 1B, the luminance triggering element includes a plurality of light-emitting diodes (LEDs), which emit wavelength λ d Luminous emission L dconfigured to emit. According to this embodiment, the diode is arranged to illuminate at least one of the illumination surfaces SI1, SI2 of the concentrator. In addition, the concentrator crystal is a fluorescent crystal, which absorbs the light emission radiation L d emitted by the LED diode, and then is designed to emit fluorescence radiation corresponding to the above-mentioned luminance radiation L F . Alternatively, according to other embodiments, the triggering element includes a laser or a flash lamp designed to excite the fluorescent crystal.

[0043] Preferably, in this embodiment, like the concentrator according to the prior art, the vertical dimension (referred to as thickness) in the direction z perpendicular to the illumination surface of the concentrator is greater than or equal to the absorption length L d of the light emission radiation L abs emitted by the concentrator. Therefore, most of the radiation emitted by the LED is absorbed by the concentrator crystal. If the thickness is too small, it will lead to substantial loss of the excitation radiation, most of which passes through the crystal without being absorbed by it, thus causing a decrease in the overall optical performance / optical performance P out / P LED , where P out is the power of the output beam at the surface FL1, and P LED is the excitation power of the LED.

[0044] Alternatively, according to the second variant of this embodiment, the luminance triggering element includes a lens or any other optical element designed to focus or direct sunlight onto the illumination surfaces SI1, SI2 of the concentrator. According to this embodiment, the concentrator is designed to absorb sunlight and then emit fluorescence radiation, which is the above-mentioned luminance radiation. This embodiment makes it possible to reduce the number of photovoltaic cells on a certain light collection surface. In fact, in the device according to the present invention, better light collection is possible than in a conventional sunlight concentrator, that is, the surface covered by the photovoltaic cells can be reduced by a factor of 10 to 100.

[0045] Importantly, the apparatus according to the present invention eliminates the limitations related to the absorption of excitation radiation in prior art fluorescent concentrators, as far as the thickness of the concentrator is concerned. In fact, there are two options for "1D" or "2D" fluorescent concentrators: - By keeping the thickness e small, absorption is reduced, thereby decreasing the efficiency of the concentrator. In this case, the brightness can be maintained at a practical level. - Alternatively, increase E to increase absorption and thus reduce luminance proportional to the ratio L / e.

[0046] In contrast, in the apparatus according to the present invention, the dimensions of the output surface can be "artificially" reduced by the first mirror M1 (and thus the brightness can be increased), while the thickness e is not reduced (and therefore the absorption of excitation radiation is not reduced). This characteristic is particularly advantageous for concentrators CL that emit light over 1 μm, which may have low absorption with respect to that. In fact, for example, in the case of doped glass concentrators, the focusing (and therefore absorption) of the light phore is limited by the interaction between ions in the material (an effect known as "quenching" of the light phore, which has the effect of limiting the emission spectroscopic properties). The apparatus according to the present invention makes it possible to use low-absorptivity materials in the concentrator, which is efficient in the infrared spectrum (up to 10 μm).

[0047] Alternatively, according to another embodiment, the concentrator is a thermoluminescent crystal, and the luminance triggering element includes a heating element configured to heat the concentrator crystal so that it emits luminance radiation by thermoluminescence. This embodiment makes it possible to use a concentrator crystal different from the fluorescent crystal.

[0048] Figure 8 shows an embodiment of the present invention in which the concentrator crystal is a cube of size α. In fact, for "3D" concentrators, there is no preferred direction as long as the plane of the large excitation surface is involved. Therefore, for example, an appropriate shape of the concentrator can be selected such that the size of the cube can be reduced. In the embodiment of Figure 8, the concentrator is a fluorescent crystal excited by the radiation L d at the illumination surface SI1. The dimension α of the cube that is the concentrator is larger than the absorption length L d of the excitation radiation L abs by the concentrator. In this embodiment, in addition to the mirrors M1 and M2 on the side surfaces FL1 and FL2, the device includes two additional mirrors M3, M4, which cover a plane parallel to the plane (xz). By these additional mirrors, the luminance radiation that is not captured by total internal reflection and should be emitted through the surface covered by the mirrors M3 and M4 can be reflected within the concentrator, thereby increasing the illumination on the output surface FS1.

[0049] In the embodiment of Figure 8, the first mirror M1 defines a square output surface with a non-covered surface area smaller than α and dimension b. Therefore, by reducing the dimension of the output surface, it is possible to increase the luminance without reducing the dimension of the cube and thus without reducing the absorption of the excitation radiation.

[0050] Figure 9 shows the results of a software simulation of the light ray path for the same device as shown in Figure 8 and a cubic fluorescent concentrator with a side of 4 mm, illuminated by an excitation radiation with power P LED = 40 W. This simulation gives the change in the output power P out of the output beam (curve P10) and the change in the illumination E (curve E10) according to the surface area SFS1 of the output surface FS1. As already seen, it is possible to significantly increase the illumination while maintaining a substantial output power. The output power P out is the transmittance T moy (and thus the ratio R) and the output beam P that would be emitted from the first side surface if the first mirror M1 were not present.out,SM The power of, Equation P out =T moy * P out,SM They are directly related based on this. When R decreases, transmittance T moy The ratio R decreases, and therefore the output power also decreases. Thus, with a ratio R=1 / 8, the illumination is E≈10W / mm². 2 The output beam power is approximately 9W.

[0051] Figures 10A and 10B illustrate an apparatus according to an embodiment of the present invention, in which the first mirror M1 is designed such that the morphology of the uncovered surface area is a disk and the letter "A," respectively. It should be understood that the position of these output surfaces FS1 on side FL1 is flexible. The output surfaces may be at the corners, in the center, mounted on the edges, or not mounted at all. These figures illustrate the modularity of the 3D concentrator apparatus with respect to the morphology of the output surfaces. Unlike filters and shields commonly used in projection, the output illumination decreases as the surface area of ​​the projected pattern decreases. This very specific characteristic allows for the creation of displays that exhibit high performance with strong illumination.

[0052] Figure 11 shows an embodiment in which the concentrator crystal has a chamfered edge AB. The chamfered edge is considered to form part of the first side surface. More specifically, the chamfered edge AB lies between the first side surface and the other surface of the concentrator crystal. This surface can be any surface adjacent to the first side surface. In the embodiment of Figure 11, the chamfered edge AB is not covered by a mirror that reflects luminance radiation. Therefore, the edge AB as a whole defines the output surface FS1.

[0053] Alternatively, according to another embodiment, only a portion of the surface area of ​​the chamfered edge is not covered by the reflective mirror, and this portion defines the output surface FS1. This embodiment makes it possible to reduce the surface area of ​​the output surface and therefore increase illumination.

[0054] Ratio R=SFS1 / SL In the calculation of the surface area S, L The surface area of ​​the chamfered edge includes the surface area of ​​the chamfered edge, and the uncovered surface area SNR1 includes the surface area of ​​the portion of the chamfered edge that is not covered by the mirror (or, if it is not covered by the mirror, the entire edge AB).

[0055] As shown in the embodiment of Figure 11, comparing the embodiment of the present invention with the aforementioned symmetrical concentrator (having only six faces arranged in pairs of two), the illumination of the output surface can be increased by 10% to 30%. In fact, by creating chamfered edges on the concentrator, a symmetrical interruption is created in the cuboid structure. More specifically, the chamfered edges artificially create a cone or supplemental relief region for specific luminance rays that are captured by total internal reflection within the cuboid concentrator, and these rays can be emitted from the concentrator by the edges. Without the chamfered edges AB, these rays cannot escape from the concentrator crystal.

[0056] Alternatively, according to other embodiments, the concentrator crystal has a chamfered corner between the first side surface and the other two faces of the concentrator. As with the embodiment in Figure 11, the chamfered corner is considered to form part of the first side surface, and this corner may or may not be partially covered with a mirror. This embodiment also makes it possible to increase illumination on the output surface compared to the embodiments of the present invention and the symmetrical concentrator described above.

[0057] Figure 12 shows an embodiment in which a first mirror M1 is mounted on a translation system ST, which is designed to move relative to a first side FL1 to increase or decrease the uncovered surface SFS1 of the output surface FS1. In this example of Figure 12, the first mirror is designed to define a rectangular output surface having dimensions x × e, where e is the thickness of the concentrator. The translation system makes it possible to control dimension s to increase or decrease the illumination E on the output surface FS1. This embodiment allows control of the illumination output from the light-emitting module EM.

[0058] The apparatus according to the present invention allows for multiple output surfaces FS1 i This enables the use of the output beam power L out This is because it is low compared to the power circulating inside the concentrator. Figure 13A shows the output FO1 of multiple fiber-supported devices. i An embodiment is shown in which the fibers are combined into a fiber group G. In this case, the brightness at the output of group G is slightly lower than the brightness at the output of a single fiber, because it is difficult to align all the fiber cores with each other. On the other hand, the power of the radiation obtained from group G is greatly increased, as is the overall performance level. In the embodiment of Figure 13A, the first mirror M1 defines n≧1 uncovered surface regions and n output beams L out,i n output surfaces FS1 through which it passes i It is designed to define n optical fibers FO. i This also includes n optical coupling systems SCi, each designed to couple output beams in different optical fibers. An optical coupling system can be, for example, one or more optical lenses. Ratio R = SFS1 / S L In the calculation of the output surface, S S All output surfaces FS1 i This is equal to the sum of the surface areas. In the representation in Figure 13A, n=2 is a non-restrictive example. Alternatively, according to other embodiments, numbers other than n=2 are used.

[0059] The use of fiber-supported output facilitates the delivery of the output beam to its application. The use of fiber-supported output in the apparatus according to the present invention is significantly simplified considering the modularity of the output surface, thereby allowing the dimensions of the output surface to match those of the optical fiber core. This is because the output surface FS1 i Related output beam L out,i related optical fiber FO i This ensures good coupling to each output beam L. out,i The geometric range needs to be adjusted. The geometric range is the product of the surface area of ​​the emitter region and the solid angle of the emitted beam.

[0060] Figure 13B shows the coupled power P in the optical fiber depending on the surface area of ​​the output surface (and therefore the geometric range). c This shows the change. As a non-limiting example, the numerical aperture of the fiber is 0.5, the core diameter is 1.5 mm, and the geometric range Et fibre =1.5 10 -2 cm 2 .sr (n=1 in this simulation). The concentrator is a Ce:YAG plate with dimensions L=100mm, w=14mm, e=1mm, and multiplying the output beam power by the output surface gives P out = 50W. In addition, it is assumed that the emission from the concentrator is of the Lambertsian type. Coupled power P in the fiber c Power P of the output beam out , the geometric range of the fiber (Et fibre ), and that of the beam on the output surface (Et c ) and the following equation: Pc=(Et fibre / Et c ).P out They are associated accordingly.

[0061] As shown in Figure 13B, the coupled power is the surface area S of the output surface. S It changes after reaching a maximum value at 380 μm, which corresponds to the range being equal in this particular case. If the surface area of ​​the output surface is smaller, all of the power emitted by the concentrator can be coupled (Et conc <Et fibre Therefore, limit the performance level (P out The transmittance of the 3D concentrator is what reduces performance. When the surface area of ​​the output surface is larger, it is the transmittance of the coupled optical system that limits the performance level, because the geometric range is insufficient. Therefore, the first mirror is preferably designed so that the geometric range of each output beam is equal to the geometric range of the optical fiber. This embodiment is designed for applications where the directivity of light must be controlled or adjusted.

[0062] Figure 14 shows an embodiment of the present invention in which the apparatus includes first and second light-emitting modules ME1 and ME2. These modules are designed such that the concentrator CL1 of the first module (referred to as the first concentrator) laterally excites the concentrator CL2 of the second light-emitting module ME2 (referred to as the second concentrator). The apparatus in Figure 14 includes a first luminance triggering element (not shown in Figure 14) associated with the first light-emitting module ME1. As already seen, this element can be a plurality of LEDs, one or more optical elements designed to direct sunlight toward the first concentrator, or an element designed to heat the concentrator.

[0063] The side of the second concentrator CL2 that is different from the side FL12 on which the second output surface FS12 is located is attached to the output surface FS11 of the first concentrator CL1. This allows the first output beam L obtained from the first light-emitting module to be out,1 This constitutes the brightness triggering element of the second light-emitting module ME2. The second concentrator CL2 absorbs the first output beam, and then the second output beam L out,2 It is designed to generate a second luminance radiation, called the second luminance radiation, whose central wavelength λ2 is shifted with respect to the central wavelength λ1 of the first output beam. This device makes it possible to generate a powerful radiation because the focusing effect accumulates in luminance.

[0064] In particular, the dimensions of the second concentrator depend solely on the dimensions of the output surface FS11 of the first concentrator CL1. Similarly, preferably, the dimensions of the plane of the second module parallel to the output surface FS11 (plane yz) of the first concentrator are smaller than or equal to the dimensions of the output surface FS11 of the first concentrator.

[0065] This point is very important because the reduction in the size of the second concentrator CL2 involves a reduction in the average distance traveled within this concentrator. moy Then, L pIt can become much smaller, which has the effect of increasing the average transmittance (see Figures 8A and 8B). This makes it possible to use CL2 material, which has a higher loss rate than CL1 material.

[0066] To ensure that the first output beam is well absorbed by the second concentrator C2, the width of the second concentrator is set to the absorption length L of the first beam by the second concentrator. abs,2 Larger. In this case, "width of the second concentrator" means the dimension of the second concentrator in the direction of the length of the first concentrator, i.e., direction x.

[0067] As a non-limiting example, the first concentrator (dimensions L2=100mm; w2=50mm; e2=1mm) is fabricated from Ce:LYSO, its first absorption band is in the UV spectrum at approximately 360nm, and the first triggering element contains a UV LED that continuously absorbs approximately 1W / mm² in the first absorption band. 2 In pulse mode, it is 2.5W / mm². 2 It emits power. The first concentrator emits the first output beam L with a center wavelength λ1 = 430 nm. out,1 The second concentrator (dimensions L2=10mm; w2=0.5mm; e2=0.25mm) is fabricated from Ce:YAG and has a second absorption band that overlaps with the spectrum of the first power beam, emitting a second power beam centered at λ2=560nm.

[0068] Considering the current technology for UV LEDs (16% filling level), it is possible to place 800 LEDs on each of the large surfaces of the first concentrator CL1. Each LED is assumed to operate in pulse mode and emit a power of 2.5W. Therefore, the excitation power is P LED =4000W. The power emitted by the first light-emitting module ME1 is therefore 550W (pulse mode) at its first side FL11, and the illumination is 11W / mm². 2These values ​​do not take into account the 3D concentrator effect by mirrors M11 and M21. In a rectangular shape, on the first output surface FS1 of the first concentrator with dimensions of 0.25 mm × 10 mm, the illumination on the first output surface FS11 is 28 W / mm² due to the 3D focusing effect. 2 This is the estimated illumination obtained.

[0069] Considering the size of the second concentrator and the surface area of ​​FS12, α 1,2 =3.10 -4 mm -1 Assuming there is some loss, the average transmittance of CL2 is 86%.

[0070] Simulations using ray tracing software can estimate the power emitted by the second concentrator when excited by the first concentrator. The conventional performance level is calculated to be 9.6%, taking into account the overlap of absorption and emission bands between the first and second concentrators. The second Ce:YAG concentrator therefore emits 34W of power at its first side FL12. This measurement does not take into account the 3D concentrator effect obtained by mirrors M12 and M22. When the surface area of ​​the second rectangular output surface FS12 is small, 25μm × 250μm, the 3D focusing effect results in 4660W / mm² on the second output surface FS2. 2 That is, 466 kW / cm² 2 The illumination is estimated to be as follows: This value represents illumination that is more than 1800 times greater than that of the LED that excites the first concentrator. Power P of the second output beam out,2 is P out,2 = 29W

[0071] The very small surface area of ​​the second output surface FS2 is selected because the dimensions of the second concentrator are such that the loss length L of the second concentrator is such that p.2 (α2=3.10 -4 mm -1 In the case of L p.2This is because the distance (=3.3m) is very small. The 3D focusing effect can therefore exhibit very high performance in the second concentrator. Thus, the average transmittance remains at a value of 86%, and the surface area of ​​the second output surface FS12 is one-tenth the surface area of ​​the side surface FL12 of the second concentrator.

[0072] The focusing coefficient of this cascaded 3D concentrator is therefore two orders of magnitude greater than that provided by a single 1D or 2D concentrator. This remarkable increase is due to the overall optical / optical performance level P out,2 / P LED This is obtained at the cost of a lower [value], which in this case is 0.7%.

[0073] However, generating this type of illumination with a laser in this wavelength range would require creating a complex conversion chain with a nonlinear crystal (there are no laser crystals that directly emit the yellow-orange spectrum). The overall optical / optical performance level would be at most a few percent. The light source proposed here is much simpler, yet the illumination is comparable to that of a laser.

[0074] It should be noted that the examples discussed here using Ce:LYSO and Ce:YAG are far from being optimized, because the fill level of UV LEDs is only 16%, compared to 40% for visible LEDs at present and potentially reaching 70% in the future.

[0075] Cascaded concentrators can be extremely advantageous for emission in the 3-5 μm infrared spectrum. In other embodiments, the first triggering element includes a visible or infrared LED (940 nm), with a packing level higher than 40%. The second concentrator is made of sulfide or selenide glass, and its losses are currently relatively high. As already seen, the problem of high losses can be avoided by using smaller concentrators.

[0076] Therefore, the cascading of 3D concentrators according to the embodiment in Figure 14 provides high flexibility in adapting to existing materials and their properties. These represent a very significant development in the field of uncorrelated light sources, which are two to three orders of magnitude larger than those currently available.

Claims

1. In the light-emitting device (1), - At least one light-emitting module (ME), - A concentrator crystal (CL) having at least six faces, two of which are parallel, including first and second faces known as sides (FL1, FL2) that are perpendicular to direction x and separated by a distance L corresponding to the horizontal dimension of the concentrator in direction x, - A first mirror (M1) configured to at least partially cover the first side surface (FL1), and the surface region (SR1) covered by the first mirror and the associated output surface (FS1, FS1 １ FS1 ２ A first mirror that defines at least one surface region (SFS1) that is not covered by the first mirror that defines the area, - A second mirror (M2) configured to cover at least 95% of the second side surface (FL2), Light-emitting module (ME) including, - Luminance radiation (L) within the concentrator crystal Ｆ A luminance triggering element (ED) designed to generate the emission of ) Includes, The aforementioned brightness triggering element is A heating element configured to heat the concentrator crystal so that it emits the luminance radiation by thermal emission, or A lens, designed to focus sunlight onto so-called illumination surfaces (SI1, SI2) of the concentrator crystal, wherein the concentrator crystal is designed to absorb the sunlight and then emit fluorescence radiation corresponding to the luminance radiation. Includes, The uncoated surface region (SFS1) and the surface region (S) of the first side surface (FL1) Ｌ The ratio R to the luminance radiation rays is determined by the average distance L, which is the distance at which the luminance radiation rays are reflected by the first and second mirrors. ｍｏｙ It propagates over the concentrator crystal and at least one output surface (FS1) １ FS1 ２ ) passes through to the output beam (L ｏｕｔ ) before forming [Math 1] The light-emitting device (1) is specified such that α is the loss coefficient per unit length of the concentrator crystal with respect to the luminance radiation.

2. The apparatus according to claim 1, wherein the ratio R is 1 / 4 or less, preferably 1 / 8 or less.

3. The luminance triggering element has a wavelength λ ｄ and includes a plurality of light emitting diodes (LEDs), lasers or flash lamps configured to emit light emission radiation (L ｄ ), the diodes being designed to illuminate at least one surface known as the illumination surface (SI1, SI2) of the concentrator crystal, the concentrator crystal being a fluorescent crystal designed to absorb the light emission radiation (L ｄ ) and then emit fluorescent radiation corresponding to the luminance radiation. The device according to any one of claims 1 and 2.

4. The vertical dimension e of the concentrator crystal in the direction z perpendicular to the illumination surface is the luminescence emission (L) from the concentrator crystal. ｄ ) Absorption length L ａｂｓ The apparatus according to claim 3, which is greater than or equal to it.

5. The apparatus according to any one of claims 1 to 4, wherein the concentrator crystal has a chamfered edge between the first side surface and another surface of the concentrator crystal, the surface area of ​​the chamfered edge is considered to form part of the surface area of ​​the first side surface in the calculation of the ratio R, and at least a portion of the surface area of ​​the chamfered edge is not covered, defining the associated output surface.

6. The apparatus according to any one of claims 1 to 4, wherein the concentrator crystal has a chamfered corner between the first side surface and the other two surfaces of the concentrator crystal, the surface area of ​​the chamfered corner is considered to form part of the surface area of ​​the first side surface in the calculation of the ratio R, and at least a portion of the surface area of ​​the chamfered corner is not covered, defining the associated output surface.

7. The first mirror is designed to define n ≥ 1 uncovered surface regions, and n output surfaces (FS1 ｉ ) is defined, and n output beams (L) are used to define that point. ｏｕｔ，１ , L ｏｕｔ，２ ) passes through, and the device also, -n optical fibers (FO ｉ )and, - n optical coupling systems (SC) designed to combine output beams in different optical fibers, each with its own unique configuration. ｉ )and, The apparatus according to any one of claims 1 to 6, including the following.

8. The apparatus according to claim 7, wherein the first mirror (M1) is designed such that the geometric range of each output beam is substantially equal to the geometric range of the optical fiber coupling the output beams.

9. The apparatus according to any one of claims 1 to 8, comprising two additional mirrors (M3, M4) that cover two parallel planes known as the cross-section of the concentrator crystal, wherein the two additional mirrors are designed to cover the entire cross-section.

10. The device includes first and second light-emitting modules (ME1, ME2) and a first luminance triggering element associated with the first light-emitting module, wherein the side of the concentrator crystal (CL2) of the second light-emitting module, different from the side surface, is the output surface (FS1) of the concentrator crystal (CL1) of the first light-emitting module. １ ) is attached to the first output beam (L) of the first light-emitting module, which is known as the primary luminescence emission. ｏｕｔ，１ ) constitutes the luminance triggering element of the second light-emitting module, and the second light-emitting module emits a second output beam (L) known as secondary luminance radiation, whose center wavelength is shifted with respect to the center wavelength of the primary luminance radiation. ｏｕｔ，２ The apparatus according to any one of claims 1 to 9, which generates ).

11. The apparatus according to claim 10, wherein the dimensions of the second light-emitting module on a vertical plane yz parallel to the output surface of the concentrator crystal of the first light-emitting module are smaller than or equal to the dimensions of the output surface of the concentrator crystal of the first light-emitting module.

12. The dimensions of the concentrator crystal of the second light-emitting module in the direction x are the absorption length L of the primary luminance radiation by the concentrator crystal of the second light-emitting module. ａｂｓ．２ A larger apparatus according to any one of claims 10 and 11.

13. The apparatus according to any one of claims 1 to 12, wherein the first mirror is mounted on a translational system (ST) designed to increase or decrease the uncovered surface by displacing the first mirror with respect to the first side surface.

14. The apparatus according to any one of claims 1 to 13, wherein the first mirror is designed such that the shape of the uncovered surface area is square, rectangular, circular, oval, triangular, or polygonal.

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