Shallow laser-phosphor tiles arrangement for general lighting

Abstract

The invention provides a light generating system (1000) comprising a first solid state light source (10), a first luminescent converter (2100), a second luminescent converter (2200), and a first thermally conductive body (3100); wherein: (A) the first luminescent converter (2100) and the second luminescent converter (2200) are configured physically separated by a shortest distance d1, thereby defining an inter-converter cavity (1200); wherein 0.3 mm ≤ d1 ≤ 3 mm; (B) the first luminescent converter (2100) comprises a first converter first major face (2110) and a first converter second major face (2120) opposite the first converter first major face (2110); wherein the first luminescent converter (2100) is configured in thermal contact with the first thermally conductive body (3100) at the first converter second major face (2120); (C) the first solid state light source (10) comprises a laser light source and / or a superluminescent diode, wherein the first solid state light source (10) is configured to generate first light source light (11); wherein the first solid state light source (10) is configured to irradiate the first converter first major face (2110) via a first optical path (31) between the first solid state light source (10) and the first luminescent converter (2100); wherein the first optical path (31) intersects at least part of the inter-converter cavity (1200) and passes by the second luminescent converter (2200); wherein the first luminescent converter (2100) is configured in the reflective mode; wherein the first luminescent converter (2100) is configured to (i) convert part of the first light source light (11) received by the first luminescent converter (2100) into first luminescent converter light (2101), and (ii) reflect at least part of the first light source light (11) received by the first luminescent converter (2100) to the second luminescent converter (2200) as reflected first light source light (111); (D) the second luminescent converter (2200) is configured to (a) convert at least part of the reflected first light source light (111) received by the second luminescent converter (2200) into second luminescent converter light (2201), and (b) transmit at least part of the first luminescent converter light (2101) received by the second luminescent converter (2200); wherein the second luminescent converter (2200) is configured in the transmissive mode; and (E) the light generating system (1000) is configured to generate system light (1001) comprising (a) first luminescent converter light (2101) transmitted by the second luminescent converter (2200) and (b) second luminescent converter light (2201).

Description

[0001] 2024PF80342

[0002] 1

[0003] Shallow laser-phosphor tiles arrangement for general lighting

[0004] FIELD OF THE INVENTION

[0005] The invention relates to a light generating system. The invention further relates to a lighting device comprising such light generating system.

[0006] BACKGROUND OF THE INVENTION

[0007] Light generating systems are known in the art. For instance, US2012230007A1 describes a semiconductor light source apparatus that can emit various color lights having a substantially uniform color tone and high brightness. The semiconductor light source apparatus can include a radiating substrate, at least one phosphor layer disposed on the radiating substrate and a semiconductor light source emitting blue light. The at least one phosphor layer can be composed of at least one of a glass phosphor and a phosphor ceramic. The light source can be located adjacent the phosphor layer so that the blue light having high brightness can be efficiently reflected on the radiating substrate via the phosphor layer while preventing the blue light from a mirror reflection on the phosphor layer.

[0008] WO2024 / 022844A1 discloses a light generating system comprising one or more solid state light sources that generate blue light, a first luminescent body, a second luminescent body and a collimator. The collimator has a first end, a second end and tapers from the second end to the first end. The first luminescent body converts at least part of the blue light into first luminescent material light and the second luminescent body converts at least part of the blue light into second luminescent material light. The first luminescent body and the second luminescent body are configured in the collimator, and the first luminescent body is configured closer to the first end than the second luminescent body. Via optics the blue light is directed to the first luminescent body and / or to the second luminescent body depending on the polarization of the blue light. Via a control system the polarization of the blue light is controlled.

[0009] SUMMARY OF THE INVENTION

[0010] High brightness light sources can be used in various applications including spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. For this2024PF80342

[0011] 2

[0012] purpose, laser-phosphor technology can be used, wherein a laser provides laser light and a remote phosphor converts the laser light into converted light. Laser-phosphor systems may allow generation of high brightness light and may therefore be used in projection systems, including displays such as cinema projectors and projectors for home, school, and office applications, car front lighting, search lighting, stage lighting, architectural lighting, and special lighting applications. In general, many components (e.g. lenses, diffusers, heat sinks, reflectors, beam guides, etc.) are needed for laser-phosphor systems to provide a suitable beam of light, having desired optical properties such as a specific color point, intensity, etc. Due to the many components, high brightness laser-phosphor systems may be relatively bulky, have a relatively complex architecture, and be relatively expensive to produce. For general lighting, however, a compact and simple architecture is preferred, which preferably can be produced at relatively low cost. Especially, luminaires such as spots or downlighting may be relatively flat, thereby requiring a relatively flat and compact lighting system.

[0013] Further, there may be a trend to provide lighting systems which may be easily repaired by a consumer at home, such that a durable and low-complexity system is desired. Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0014] According to a first aspect, the invention provides a light generating system comprising a first solid state light source, a first luminescent converter, a second luminescent converter, and a first thermally conductive body. The first luminescent converter and the second luminescent converter may be configured physically separated (from each other) by a shortest (face-to-face) distance di. As such, the first luminescent converter and the second luminescent converter may define an inter-converter cavity. In embodiments, 0.3 mm < di < 3 mm (may apply). Further, the first luminescent converter may comprises a first converter first major face and a first converter second major face opposite the first converter first major face. Especially, the first luminescent converter may be configured in thermal contact with the first thermally conductive body via the first converter second major face. The first solid state light source may comprise one or more of a laser light source and a superluminescent diode. Further, the first solid state light source may be configured to generate first light source light. The first light source light may especially have a first peak wavelength (λp₁) selected from the range of 380-490 nm. Further, the first solid state light source may be configured to irradiate the first converter first major face via a first optical path between the2024PF80342

[0015] 3

[0016] first solid state light source and the first luminescent converter. The first optical path between the first solid state light source and the first luminescent converter may intersect at least part of the inter-converter cavity, and may pass by (but not intersect) the second luminescent converter. Further, the first luminescent converter may be configured in the reflective mode. Especially, the first luminescent converter may be configured to (i) convert (at least) part of the first light source light received by the first luminescent converter into first luminescent converter light, and (ii) reflect at least part of the first light source light received by the first luminescent converter as reflected first light source light to the second luminescent converter via the inter-converter cavity. Hence, the second luminescent converter may be configured downstream of the first luminescent converter. Further, the second luminescent converter may be configured to convert at least part of the reflected first light source light received by the second luminescent converter into second luminescent converter light. Additionally or alternatively, the second luminescent converter may be configured to transmit at least part of the first luminescent converter light received by the second luminescent converter via the inter-converter cavity. Hence, the second luminescent converter may be configured in the transmissive mode. In embodiments, the light generating system may be configured to generate system light comprising (a) first luminescent converter light transmitted by the second luminescent converter, and (b) second luminescent converter light (generated by the second luminescent converter). Hence, in specific embodiments, the invention provides a light generating system comprising a first solid state light source, a first luminescent converter, a second luminescent converter, and a first thermally conductive body; wherein: (A) the first luminescent converter and the second luminescent converter are configured physically separated by a shortest distance di, thereby defining an inter-converter cavity; wherein 0.3 mm < di < 3 mm; (B) the first luminescent converter comprises a first converter first major face and a first converter second major face opposite the first converter first major face; wherein the first luminescent converter is configured in thermal contact with the first thermally conductive body via the first converter second major face; (C) the first solid state light source comprises one or more of a laser light source and a superluminescent diode, wherein the first solid state light source is configured to generate first light source light; wherein the first light source light has a first peak wavelength (λp₁) selected from the range of 380-490 nm; wherein the first solid state light source is configured to irradiate the first converter first major face via a first optical path between the first solid state light source and the first luminescent converter; wherein the first optical path between the first solid state light source and the first luminescent converter intersects at least part of the inter-converter cavity2024PF80342

[0017] 4

[0018] and passes by the second luminescent converter; wherein the first luminescent converter is configured in the reflective mode; wherein the first luminescent converter is configured to (i) convert part of the first light source light received by the first luminescent converter into first luminescent converter light, and (ii) reflect at least part of the first light source light received by the first luminescent converter as reflected first light source light to the second luminescent converter via the inter-converter cavity; (D) the second luminescent converter is configured downstream of the first luminescent converter; wherein the second luminescent converter is configured to (a) convert at least part of the reflected first light source light received by the second luminescent converter into second luminescent converter light, and (b) transmit at least part of the first luminescent converter light received by the second luminescent converter via the inter-converter cavity; wherein the second luminescent converter is configured in the transmissive mode; and (E) the light generating system is configured to generate system light comprising (a) first luminescent converter light transmitted by the second luminescent converter, and (b) second luminescent converter light.

[0019] Such a light generating system may especially provide high brightness light. Further, such a light generating system may be relatively compact, and may have a relatively simple architecture. Hence, such a light generating system may be relatively cheap to produce compared to conventional laser-phosphor systems. Further yet, the first solid state light source may exit the light generating system after (at least) one reflection at the first luminescent converter, and after being transmitted through the second luminescent converter. Hence, such a light generating system may prevent the first light source light from (directly) escaping the light generating system upon damage to one of the luminescent converter, thereby providing a light generating system with improved (consumer) safety.

[0020] The light generating system may comprise the first solid state light source. The first solid state light source may be selected from the group comprising a light emitting diode (LED), a laser diode, a superluminescent diode, and a (stacked) multi -junction light emitting diode, though other options may also be possible (see below). Especially, the first solid state light source may comprise, such as be, a laser light source or a superluminescent diode. Further, the first solid state light source may be configured to generate first light source light. The first light source light may have a first peak wavelength (λp₁) selected from the range of 370-500 nm, such as from the range of 380-490 nm, especially from the range of 400-490 nm. Further, the first peak wavelength (λp₁) may be selected from the range of 420-490 nm, such as from the range of 430-490 nm, especially from the range of 440-465 nm. Hence, the first light source light may be one of violet light and blue light, such as especially blue light.2024PF80342

[0021] 5

[0022] The term “violet light”, and similar terms, may especially relate to light having a wavelength in the range of about 380-440 nm. The term “blue light”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm. The term “peak emission wavelength”, and similar terms, may refer to the wavelength where the radiometric emission spectrum of the light source reaches its maximum, i.e., the peak emission wavelength may denote the wavelength at which the largest (emission intensity) value is found in a graph of the spectral power distribution. The peak emission wavelength may especially be determined at room temperature.

[0023] The light generating system may further comprise a first luminescent converter and a second luminescent converter. The first luminescent converter and the second luminescent converter may be configured in a light receiving relationship with the first solid state light source. Especially, the first luminescent converter and the second luminescent converter may be configured downstream from the first solid state light source. Further, the second luminescent converter may be configured downstream of the first luminescent converter. The terms “downstream” and “upstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here especially the solid state light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”.

[0024] Hereafter, some general embodiments relating to the first luminescent converter and( / or) the second luminescent converter may be provided. Unless otherwise specified, embodiments related to a “luminescent converter” may relate to one or both of the first luminescent converter and the second luminescent converter. The luminescent converter may be a layer, like a self-supporting layer. The luminescent converter may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode, or a reflective support in the reflective mode). Yet, especially, the luminescent converter may be essentially self-supporting. Further, the luminescent converter may be light transparent or light scattering. In embodiments, the luminescent converter may comprise a luminescent material (or “phosphor”, see also further below). Further, in embodiments, the luminescent converter may comprise a (light transmissive) matrix material, wherein the luminescent material may be embedded in the (light transmissive) matrix material. For instance, the luminescent converter may comprise a glass or polymeric body, with luminescent material embedded therein. In such embodiments, the refractive indices of the2024PF80342

[0025] 6

[0026] matrix material and the luminescent material may be “matched”, such as differ by < 0.05, especially by < 0.02, like by < 0.01, including (essentially) by 0.00. Alternatively, the luminescent material may be provided as a luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. A luminescent single crystal may also be referred to as a “crystalline phosphor tile”, and may especially refer to a (tile of) luminescent material consisting of a single crystal. A luminescent ceramic body may also be referred to as a “ceramic phosphor tile”, and may especially refer to a luminescent material powder compressed into a (solid) tile of luminescent material. In embodiments, one or more of the first luminescent converter and the second luminescent converter may be a crystalline phosphor tile. Additionally or alternatively, one or more of the first luminescent converter and the second luminescent converter may be a ceramic phosphor tile. Alternatively, the luminescent converter may comprise a luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. That is, one or more of the first luminescent converter and the second luminescent converter may comprise a ceramic phosphor tile. Additionally or alternatively, one or more of the first luminescent converter and the second luminescent converter may comprise a crystalline phosphor tile. Hence, in specific embodiments, one or more may apply of: (i) one or more of the first luminescent converter and the second luminescent converter may comprise a ceramic phosphor tile; and (ii) one or more of the first luminescent converter and the second luminescent converter may comprise a crystalline phosphor tile. A ceramic phosphor tile and / or a crystalline phosphor tile may have a higher thermal conductivity compared to a luminescent material (powder) embedded in a matrix material. Further, a ceramic phosphor tile and / or a crystalline phosphor tile may be more resistant against photodegradation compared to a luminescent material (powder) embedded in a matrix material. Additionally, the concentration of luminescent material may in a ceramic phosphor tile and / or a crystalline phosphor tile may be relatively high, such that the height (or thickness) of the (first and / or second) luminescent converter may be reduced.

[0027] The luminescent converter may have any shape. In general, however, the luminescent converter may comprise two essentially parallel faces, defining a height (of the luminescent converter). In embodiments, the two essentially parallel faces may define a first major face and a second major face of the luminescent converter. Hence, the first luminescent converter may comprise a first converter first major face and a first converter second major face opposite (and parallel to) the first converter first major face. Similarly, the second luminescent converter may comprise a second converter first major face and a second2024PF80342

[0028] 7

[0029] converter second major face opposite (and parallel to) the second converter first major face. Further, the luminescent converter may comprise one or more side faces, bridging the first major face and the second major face. Hence, the first luminescent converter may comprise one or more first converter side faces configured bridging the first converter first major face and the first converter second major face. Similarly, the second luminescent converter may comprise one or more second converter side faces configured bridging the second converter first major face and the second converter second major face. The one or more side faces may be curved in one or two dimensions. Alternatively, the one or more side faces may be planar.

[0030] The luminescent converter may have a rectangular or circular cross-section (in a plane parallel to the first major face and / or the second major face), though other crosssections may also be possible, like e.g. hexagonal, octagonal, etc. Hence, the luminescent converter may have a circular cross-section, an oval cross-section, a square cross-section, or a non-square rectangular cross-section. In embodiments, the luminescent converter may have an n-gonal cross-section, wherein n is at least 3, like 4 (square or rectangular cross-section), 5 (pentagonal cross-section), 6 (hexagonal cross-section), 8 (octagonal cross-section) or higher. Perpendicular to the aforementioned cross-section may be another cross-section, which may in embodiments be rectangular. Hence, the luminescent converter may e.g. have a cubic shape, a (non-cubic) cuboid shape, an n-gonal prism shape with n being at least 5 (such as pentagonal prism, hexagonal prism), and a cylindrical shape. Other shapes, however, may also be possible. Especially, the luminescent converter may have a cuboid shape, a cylindrical shape, or an n-gonal prism shape wherein n is 6 or 8.

[0031] In embodiments, the luminescent converter has lateral dimensions width (W) and length (L), and a thickness or height (H). The width (W) and length (L) of the luminescent converter may especially be defined by the first major face and / or the second major face. Further, the height (H) of the luminescent converter may especially be determined perpendicular to the first (and / or second) major face (i.e., the height (H) may be defined by the one or more side faces). In embodiments, L < 10 mm, such as L < 5 mm, especially L < 3 mm, like L < 2 mm. Additionally or alternatively, in embodiments, W < 10 mm, such as W < 5 mm, especially W < 3 mm, like W < 2 mm. Further, in embodiments, H < 10 mm, such as H < 5 mm, especially H < 3 mm, like H < 2 mm. In specific embodiments, the luminescent converter may have a height (H) in the range of 50 pm - 1 mm. Further, the luminescent converter may have lateral dimensions (width and / or length) in the range of 100 pm - 10 mm. In embodiments, L > H may apply, such as L > 2*H, especially L > 5*H, like L > 7*H. Additionally or alternatively, in embodiments, W > H may apply, such as W > 2*H,2024PF80342

[0032] 8

[0033] especially W > 5*H, like W > 7*H. Hence, in specific embodiments, the first luminescent converter may have a first length (Li), a first width (Wi), and a first height (Hi). Similarly, the second luminescent converter may have a second length (L2), a second width (W2), and a second height (H2). In embodiments, the first luminescent converter and the second luminescent converter may have the same size (i. e., Li = L2, Wi = W2, and Hi = H2).

[0034] Alternatively, the first luminescent converter and the second luminescent converter may differ in size, such that one or more may apply of (i) Li L2, (ii) Wi W2, and (iii) Hi H2. Especially, in embodiments, the first luminescent converter and the second luminescent converter may differ in height. In embodiments, Hi < H2, such as Hi < 0.9*H2, especially Hi < 0.7*H2. Additionally or alternatively, in embodiments, Hi > 0.1 *H2, such as Hi > 0.2*H2, especially Hi > 0.3*H2. Additionally or alternatively, in embodiments, H2 < Hi, such as H2 < 0.9*Hi, especially H2 < 0.7*Hi. Additionally or alternatively, in embodiments, H2 > 0.1*Hi, such as H2 > 0.2*Hi, especially H2 > 0.3*Hi. Hence, in specific embodiments, the first luminescent converter may have a first height Hi, and the second luminescent converter may have a second height H2; wherein H2 < 0.9*Hi. A second luminescent converter having a relatively lower height may facilitate reducing the amount of first luminescent converter light absorbed (and optionally converted) by the second luminescent converter. Further, a relatively thinner second luminescent converter may facilitate providing a relatively compact light generating system.

[0035] As indicated above, the second luminescent converter may be configured downstream of the first luminescent converter (with respect to the first solid state light source). Further, the second luminescent converter may be configured physically separated from the first luminescent converter. Especially, the first luminescent converter and the second luminescent converter may be configured physically separated by a shortest (face-to-face) distance di. In embodiments, the shortest (face-to-face) distance di may be selected from the range of > 0.1 mm, such as from the range of > 0.2 mm, especially from the range of > 0.3 mm, like from the range of > 0.5 mm. Additionally or alternatively, the shortest (face-to-face) distance di may be selected from the range of < 7 mm, such as from the range of < 5 mm, especially from the range of < 3 mm, like from the range of < 2 mm. Hence, in embodiments, 0.1 mm < di < 7 mm (may apply), such as 0.2 mm < di < 5 mm, especially 0.3 mm < di < 3 mm, like 0.5 mm < di < 2 mm. In embodiments, the physical separation between the first luminescent converter and the second luminescent converter may define an interconverter cavity (see also below).2024PF80342

[0036] 9

[0037] In embodiments, the first luminescent converter and the second luminescent converter may be configured parallel (with respect to each other). Especially, the first converter first major face may be configured parallel to the second converter first major face. Herein, the term “parallel”, and similar terms, may indicate that an angle between a first element and a second element parallel to said first element may be < 5°, such as < 3°, especially < 2°, like < 1°. Alternatively, the first luminescent converter and the second luminescent converter may be configured at an angle with respect to each other, such as an angle selected from the range of 1-40°, especially from the range of 2-30°, like from the range of 3-20°. Yet, especially, the first luminescent converter may be configured parallel to (e.g. at an angle of < 2° with) the second luminescent converter. Hence, in specific embodiments, the first luminescent converter and the second luminescent converter may be configured parallel. Configuring the second luminescent converter parallel to the first luminescent converter may reduce the amount of first light source light and / or first luminescent converter light reflected at the second luminescent converter, thereby improving the efficiency of the system.

[0038] Hence, the first luminescent converter and the second luminescent converter may be configured parallel. Further, the first luminescent converter and the second luminescent converter may be configured aligned (in a direction perpendicular to the first converter first major axis). That is, in embodiments, in a direction perpendicular to the first converter first major face, a geometrical center of the second luminescent converter may overlap with a geometrical center of the first luminescent converter. Would the first luminescent converter and second luminescent converter have the same dimensions length and width, the second luminescent converter may further fully overlap the first luminescent converter in the direction perpendicular to the first converter first major face. Alternatively, in embodiments, one of the first luminescent converter and the second luminescent converter may be larger than the other of the first luminescent converter and the second luminescent converter, wherein the larger of the two may extend in all directions beyond the smaller of the two (in the direction perpendicular to the first converter first major face). Yet, in embodiments, the first luminescent converter and the second luminescent converter may not be aligned in a direction perpendicular to the first converter first major face. In such embodiments, the first luminescent converter and the second luminescent converter may have the same dimensions length and width, wherein the first luminescent converter and the second luminescent converter may be configured staggered in the direction perpendicular to the first converter first major face. Alternatively, one of the first luminescent converter and2024PF80342

[0039] 10

[0040] the second luminescent converter may be larger than the other of the first luminescent converter and the second luminescent converter, wherein the larger of the two may extend in at least one direction beyond the smaller of the two (in the direction perpendicular to the first converter first major face). For instance, in the direction perpendicular to the first converter first major face, the first solid state light source may be configured on a first side of the first luminescent converter, and the second luminescent converter (having the same or a larger size than the first luminescent converter) may extend beyond the first luminescent converter at a second (opposite) side of the first luminescent converter. Such a configuration may facilitate that, would the first solid state light source irradiate the first luminescent converter at an angle (selected from the range of 10-80°), both the first luminescent converter and the second luminescent converter may be irradiated with (reflected) first light source light at the center of the respective luminescent converter (without the need for redirection optics).

[0041] Turning to the first luminescent converter, the first luminescent converter may be configured physically separated from the first solid state light source. Further, the first luminescent converter may be configured downstream of and in a light receiving relationship with the first solid state light source. Especially, the first converter first major face may be configured in a light receiving relationship with the first solid state light source. Hence, the first solid state light source may be configured to irradiate the first converter first major face. In embodiments, the first light source light may propagate along a first optical path between the first solid state light source and (the first converter first major face of) the first luminescent converter. The first optical path may further be referred to as a first optical axis, and may indicate the path along which the first light source light (on average) propagates between the first solid state light source and (the first converter first major face of) the first luminescent converter. In embodiments, the first optical path may intersect at least part of the inter-converter cavity. That is, the first optical path may be at least partially configured between the first luminescent converter and the second luminescent converter. Further, the first optical path may pass by (and not intersect) the second luminescent converter. Hence, in embodiments, the first optical path may enter the inter-converter cavity from a side of the inter-converter cavity (and be incident on the first luminescent converter). Alternatively, the first optical path may enter the inter-converter cavity from a top of the inter-converter cavity, wherein the second luminescent converter may be configured staggered with respect to the first luminescent converter, such that the first optical path passes by (and does not intersect) the second luminescent converter.2024PF80342

[0042] 11

[0043] The first optical path (or “first optical axis”) may be configured perpendicular to the first converter first major face. Alternatively, and especially, the first optical path (incident on the first luminescent converter) may be configured at a (smallest) first angle (α₁) with the first converter first major face. In embodiments, the (smallest) first angle (α₁) may be selected from the range of ≥ 10°, such as from the range of ≥ 20°, especially from the range of ≥ 30°, like from the range of ≥ 40°. Additionally or alternatively, the (smallest) first angle (α₁) may be selected from the range of ≤ 80°, such as from the range of ≤ 70°, especially from the range of ≤ 60°, like from the range of ≤ 50°. Hence, in embodiments, 10° ≤ α₁ ≤ 80° (may apply), such as 20° ≤ α₁ ≤ 70°, especially 30° ≤ α₁ ≤ 60°, like 40° ≤ α₁ ≤ 50°. That is, the first optical path may be configured at a (smallest) angle (α₁ₙ) with respect to a (surface) normal to the first converter first major face of 80° ≥ α₁ₙ ≥ 10°, such as 70° ≥ α₁ₙ ≥ 20°, especially 60° ≥ α₁ₙ ≥ 30°, like 50° ≥ α₁ₙ ≥ 40°. Hence, in specific embodiments, the first optical path incident on the first luminescent converter may be configured at a first angle (α₁) with the first converter first major face; wherein 20° ≤ α₁ ≤ 70°. Such a (smallest) first angle (α₁) may facilitate that at least part of the first light source light may be reflected towards the second luminescent converter by the first luminescent converter. Yet, such a (smallest) first angle (α₁) may facilitate that at least part of the first light source light may be converted by the first luminescent converter.

[0044] Hence, the first luminescent converter may be configured to convert (at least) part of the first light source light received by the first luminescent converter into first luminescent converter light. In embodiments, the first luminescent converter may be configured to convert > 80%, such as > 90%, especially > 95%, like > 97%, of the first light source light received by the first luminescent converter into first luminescent converter light. Additionally or alternatively, the first luminescent converter may be configured to convert < 99.5%, such as < 99%, especially < 98%, of the first light source light received by the first luminescent converter into first luminescent converter light. The first luminescent converter light may have a first centroid wavelength (Xci ). The term “centroid wavelength”, also indicated as Zc. is known in the art, and refers to the wavelength value (in nm) where half of the light energy is at shorter and half the energy is at longer wavelengths. It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula λc = Σ λ* I(λ) / (Σ I( λ)), where the summation is over the wavelength range of interest, and I(λ) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions. In embodiments,2024PF80342

[0045] 12

[0046] the first centroid wavelength (λc₁) may be selected from the range of 380-780 nm. That is, the first luminescent converter light may especially be visible light. The terms “visible light” or “visible emission”, and similar terms, refer to light having one or more wavelengths in the range of about 380-780 nm. In embodiments, the first luminescent converter light may be any color light (such as have any color point selected from the CIE 1931 color space). Yet, especially, the first centroid wavelength (λc₁) may be selected from the range of 480-600 nm, such as from the range of 490-590 nm, especially from the range of 510-570 nm. Hence, the first luminescent converter light may comprise, such as be, one or more of green light and yellow light. The term “green light”, and similar terms, may especially relate to light having a wavelength in the range of about 490-560 nm. The term “yellow light”, and similar terms, may especially relate to light having a wavelength in the range of about 560-590 nm.

[0047] Further, the first luminescent converter light may comprise at least one emission band having a first luminescent full width at half maximum FWHM1₁ of ≥ 30 nm, such as ≥ 40 nm, especially ≥ 60 nm. Additionally or alternatively, the first luminescent converter light may comprise the at least one emission band having a first luminescent full width at half maximum FWHM1₁ of ≤ 200 nm, such as ≤ 175 nm, especially ≤ 150 nm. In embodiments, the first luminescent converter light may comprise a plurality of emission bands, wherein at least one band may have the first luminescent full width at half maximum FWHM1₁. Alternatively, the first luminescent converter light may comprise a single emission band, wherein said emission band may have the first luminescent full width at half maximum FWHM1₁. The term “emission band” may refer to the emission (spectral power distribution) resulting from a radiative transition of electrons from (vibrational levels of) a first higher-energy excited state to (vibrational levels of) a second lower-energy (ground) state, wherein a larger number of vibrational levels in (one or more of) the first excited state and second (ground) state results in a broader emission band (spanning a larger wavelength range). Further, the term “luminescent full width at half maximum” (or “luminescent FWHM”) may refer to the width of (the spectral power distribution of) the emission band at half the maximum intensity of said emission band. The luminescent FWHM of an emission band may especially be determined at room temperature.

[0048] Further, the first luminescent converter may be configured to reflect at least part of the first light source light received by the first luminescent converter to the second luminescent converter as reflected first light source light. The first luminescent converter may especially reflect the reflected first light source light to the second luminescent converter via the inter-converter cavity. In embodiments, the first luminescent converter may be2024PF80342

[0049] 13

[0050] configured to reflect < 20%, such as < 10%, especially < 5%, like < 3%, of the first light source light received by the first luminescent converter to the second luminescent converter (via the inter-converter cavity) as reflected first light source light. Additionally or alternatively, the first luminescent converter may be configured to reflect > 0.5%, such as > 1%, especially > 2%, of the first light source light received by the first luminescent converter to the second luminescent converter (via the inter-converter cavity) as reflected first light source light.

[0051] Hence, the first luminescent converter may be configured to reflect at least part of the first light source light received by the first luminescent converter. Further, the first luminescent converter may be configured to emit the first luminescent converter light from the first converter first major face. That is, the first luminescent converter light may escape the first luminescent converter via the first converter first major face. Hence, in embodiments, the first luminescent converter may be configured in the reflective mode. Herein, the term “reflective mode” may indicate that when (first) light source light is reflected at the first luminescent converter, it may have a direction overlapping with the direction in which the first luminescent material light escapes from the first luminescent converter. Hence, in the reflective mode, the first light source light may be incident on the first converter first major face, and the first luminescent converter light may exit the first luminescent converter via the first converter first major face. Configuring the first luminescent converter in the reflective mode may improve thermal management, as the absorption and conversion of light may be spread over a larger optical path length within the first luminescent converter. Further, configuring the first luminescent converter in the reflective mode may facilitate placing the first thermally conductive body in thermal contact with the first converter second major face, thereby further improving thermal management. In embodiments, the first converter second major face may comprise a reflective coating (to provide the reflective mode). Alternatively, the first luminescent converter may be configured in physical contact with a reflective mirror (and / or substrate) at the first converter second major face.

[0052] Hence, the first luminescent converter may be configured to reflect at least part of the first light source light received by the first luminescent converter. In specific embodiments, the first luminescent converter may be configured to specularly reflect the at least part of the first light source light received by the first luminescent converter. Specular reflection of first light source light at the first luminescent converter may provide the benefit that an angular intensity distribution of the reflected first light source light may be2024PF80342

[0053] 14

[0054] (essentially) the same as an angular intensity distribution of the first light source light incident on the first luminescent converter, thereby facilitating providing a relatively narrow beam of reflected first light source light to the second luminescent converter.

[0055] Yet, alternatively, the at least part of the first light source light reflected at the first luminescent converter (as reflected first light source light) may be (at least partially) scattered at the first luminescent converter. Scattering of the first light source light may occur due to one or more of surface scattering and volume scattering. In embodiments, the scattering of the first light source light at the first luminescent converter may result in an increase in a full width at half maximum (FWHM) in an angular intensity distribution of the reflected first light source light (compared to a FWHM in an angular intensity distribution of the first light source light incident on the first luminescent converter). Hence, in embodiments, the first light source light (incident on the first luminescent converter) may have a first full width at half maximum (FWHM1). The first full width at half maximum (FWHM1) of the first light source light may especially be determined by an angular intensity distribution of the first light source light in a cross-section of the first light source light perpendicular to the first optical path. In embodiments, the first full width at half maximum (FWHM1) may be selected from the range of < 40°, such as from the range of < 30°, especially from the range of < 20°, like from the range of < 10°. Additionally or alternatively, the first full width at half maximum (FWHM1) may be selected from the range of > 1°, such as from the range of > 2°, especially from the range of > 3°. Further, the reflected first light source light (upstream of the second luminescent converter) may have a second full width at half maximum (FWHM2). The second full width at half maximum (FWHM2) of the reflected first light source light may especially be determined by an angular intensity distribution of the reflected first light source light in a cross-section of the reflected first light source light perpendicular to a direction of propagation (between the first luminescent converter and second luminescent converter) of the reflected first light source light. In embodiments, the second full width at half maximum (FWHM2) may be selected from the range of > 5°, such as from the range of > 10°, especially from the range of > 12°. Additionally or alternatively, the second full width at half maximum (FWHM2) may be selected from the range of < 80°, such as from the range of < 70°, especially from the range of < 60°, like from the range of < 50°. Further, in embodiments, FWHM2 > FWHM1 (may apply), such as (FWHM2 -FWHM1) > 10°, especially (FWHM2 - FWHM1) > 20°, like (FWHM2 - FWHM1) > 30°, such as (FWHM2 - FWHM1) > 40°. Additionally or alternatively, in embodiments, (FWHM2 - FWHM1) < 70° (may apply), such as (FWHM2 - FWHM1) < 60°, especially2024PF80342

[0056] 15

[0057] (FWHM2 - FWHM1) < 50°, like (FWHM2 - FWHM1) < 40°. Hence, in specific embodiments, the first light source light may have a first full width at half maximum (FWHM1), and the reflected first light source light may have a second full width at half maximum (FWHM2); wherein (FWHM2 - FWHM1) > 30°. Such a difference in FWHM before and after reflection may facilitate that the reflected light source light irradiating the second luminescent converter may have a broader beam width, thereby distributing the (intensity of the) reflected light source light over a larger surface area on the second converter, thus improving thermal management in the second converter.

[0058] Hence, the first luminescent converter may be configured to reflect at least part of the first light source light to the second luminescent converter as reflected first light source light. Further, the first luminescent converter may be configured to emit first luminescent converter light (from the first converter first major face) to the second luminescent converter. Hence, the reflected first light source light and the first luminescent converter light may be incident on the second luminescent converter. Especially, the reflected first light source light and the first luminescent converter light may be incident on the second luminescent converter via the inter-converter cavity. Further, as indicated above, the second luminescent converter may have a second converter first major face and a second converter second major face. In embodiments, the second converter first major face may be configured facing (and optionally parallel to) the first luminescent converter. Further, in embodiments, the (beam of) reflected first light source light may be incident on (the second converter first major face of) the second luminescent converter from a direction perpendicular to the second converter first major face. Alternatively, the (beam of) reflected first light source light may be incident on the second luminescent converter at a (smallest) angle (011,2) with the second converter first major face. In embodiments, 10° ≤ α₁,₂ ≤ 80° (may apply), such as 20° ≤ α₁,₂ ≤ 70°, especially 30° ≤ α₁,₂ ≤ 60°, like 40° ≤ α₁,₂ ≤ 50°. Especially, in embodiments, the first luminescent converter and the second luminescent converter may be configured parallel, and |α₁,₂ - α₁| ≤ 5° may apply, such as |α₁,₂ - α₁| ≤ 3°, especially |α₁,₂ - α₁| ≤ 2°, like (essentially) α₁,₂ = α₁.

[0059] The second luminescent converter may be configured to convert at least part of the reflected first light source light received by the second luminescent converter into second luminescent converter light. Especially, the second luminescent converter may be configured to convert > 50%, such as > 60%, especially > 70%, of the reflected first light source light received by the second luminescent converter into second luminescent converter light. Further, in embodiments, the second luminescent converter may be configured to2024PF80342

[0060] 16

[0061] convert > 80%, such as > 90%, especially > 95%, including (essentially) 100%, of the reflected first light source light received by the second luminescent converter into second luminescent converter light. Additionally or alternatively, the second luminescent converter may be configured to transmit at least part of the reflected first light source light received by the second luminescent converter. Hence, in embodiments, the second luminescent converter may be configured to convert < 95%, such as < 90%, especially < 80%, of the reflected first light source light received by the second luminescent converter into second luminescent converter light. Further, the second luminescent converter may be configured to transmit > 5%, such as > 10%, especially > 20%, of the reflected first light source light received by the second luminescent converter. Additionally or alternatively, the second luminescent converter may be configured to transmit < 50%, such as < 40%, especially < 30%, of the reflected first light source light received by the second luminescent converter.

[0062] The second luminescent converter may further be configured to transmit at least part of the first luminescent converter light received by the second luminescent converter (via the inter-converter cavity). Especially, the second luminescent converter may be configured to transmit > 70%, such as > 80%, especially > 90%, of the first luminescent converter light received by the second luminescent converter. Further, the second luminescent converter may be configured to transmit > 90%, such as > 95%, especially > 98%, including (essentially) 100%, of the first luminescent converter light received by the second luminescent converter. Hence, in specific embodiments, the second luminescent converter may be configured to transmit at least 80% of the first luminescent converter light received by the second luminescent converter. A second luminescent converter configured to transmit at least 80% of the first luminescent converter light may reduce the amount of heat generated in the second luminescent converter by absorption of the first luminescent converter light, and may improve the efficiency of the light generating system.

[0063] In embodiments, the second luminescent converter may be configured to convert > 1%, such as > 2%, especially > 3%, of the first luminescent converter light received by the second luminescent converter into second luminescent converter light. Yet, especially, the second luminescent converter may be configured to convert < 20%, such as < 10%, especially < 5%, like < 3%, of the first luminescent converter light received by the second luminescent converter into second luminescent converter light. Hence, in specific embodiments, the second luminescent converter may be configured to convert at most 20% of the first luminescent converter light received by the second luminescent converter into second luminescent converter light. A light generating system comprising such a second2024PF80342

[0064] 17

[0065] luminescent converter may be more efficient, and energy may be lost upon conversion of first luminescent converter light into second luminescent converter light.

[0066] The second luminescent converter light may have a second centroid wavelength (λc₂). In embodiments, the second centroid wavelength (λc₂) may be selected from the range of 380-780 nm. That is, the second luminescent converter light may especially be visible light. In embodiments, the second luminescent converter light may be any color light (such as have any color point selected from the CIE 1931 color space). Yet, especially, the second centroid wavelength (λc₂) may be selected from the range of 580-700 nm, such as from the range of 590-690 nm, especially from the range of 600-670 nm. Hence, the second luminescent converter light may comprise, such as be, one or more of orange light and red light, such as especially red light. The terms “orange light” or “orange emission”, and similar terms, may especially relate to light having a wavelength in the range of about 590-620 nm. The terms “red light” or “red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 620-780 nm. The second centroid wavelength (λc₂) may be (roughly) equal to the first centroid wavelength (λc₁), such as differ by ≤ 5 nm, especially by ≤ 2 nm, including by (essentially) 0 nm. Alternatively, the second centroid wavelength (λc₂) may differ from the first centroid wavelength (λc₁). In embodiments, |λc₂-λc₁| ≥ 5 nm (may apply), such as |λc₂-λc₁| ≥ 10 nm, especially |λc₂-λc₁| ≥ 20 nm. Additionally or alternatively, in embodiments, |λc₂-λc₁| ≤ 50 nm (may apply), such as |λc₂-λc₁| ≤ 40 nm, especially |λc₂-λc₁| ≤ 30 nm. Hence, in specific embodiments, the first luminescent converter light may have a first centroid wavelength (λc₁) selected from the range of 490-590 nm, and the second luminescent converter light may have a second centroid wavelength (λc₂) selected from the range of 590-690 nm. A light generating system configured to provide such (green or yellow) first luminescent converter light and such (orange or red) second luminescent converter light may facilitate providing white system light (upon admixing blue light, e.g. blue first light source light, into the luminescent converter light). Hence, such a light generating system may be suitable for general lighting applications.

[0067] The second luminescent converter light may comprise at least one emission band having a second luminescent full width at half maximum FWHM2₂ of ≥ 30 nm, such as ≥ 40 nm, especially ≥ 60 nm. Additionally or alternatively, the second luminescent converter light may comprise the at least one emission band having a second luminescent full width at half maximum FWHM2₂ of ≤ 200 nm, such as ≤ 175 nm, especially ≤ 150 nm. Hence, the second luminescent converter light may comprise broadband emission. Additionally or alternatively, the second luminescent converter light may comprise narrowband emission.2024PF80342

[0068] 18

[0069] That is, the second luminescent converter light may comprise at least one emission band having a second luminescent full width at half maximum FWHM2₂ of ≤ 50 nm, such as ≤ 40 nm, especially ≤ 30 nm. The second luminescent converter light may comprise a plurality of emission bands, wherein at least one band may have the second luminescent full width at half maximum FWHM2₂. Alternatively, the second luminescent converter light may comprise a single emission band, wherein said emission band may have the second luminescent full width at half maximum FWHM2₂.

[0070] As indicated above, the second luminescent converter may be configured to transmit at least part of the first luminescent converter light, and optionally at least part of the reflected first light source light, received by the second luminescent converter. Especially, the second luminescent converter may receive the first luminescent converter light and the reflected first light source light at the second converter first major face, and may emit the transmitted first luminescent converter light, second luminescent converter light, and optionally transmitted reflected first light source light from the second converter second major face. That is, the transmitted first luminescent converter light, second luminescent converter light, and optionally transmitted reflected first light source light may leave the second luminescent converter via the second converter second major face. Hence, the second luminescent converter may be configured in the transmissive mode. Herein, the term “transmissive mode” may indicate that when at least part of the (first) light source light is propagating in the same direction from the second luminescent converter as it was propagating to the second luminescent converter directly upstream of the second luminescent converter, it may have a direction overlapping with the direction in which the (first and / or second) luminescent converter light escapes from the second luminescent converter.

[0071] Configuring the second luminescent converter in the transmissive mode may provide the benefit that a light exit of the light generating system may be configured relative to the second luminescent converter opposite the first luminescent converter, such that the first solid state light source light may emit first light source light in a direction away from the light exit, thereby providing a more safe light generating system.

[0072] As indicated above, the reflected first light source light received at the second converter first major face may have a second full width at half maximum (FWHM2). Further, in embodiments, the second luminescent converter may be configured to transmit at least part of the reflected first light source light received by the second luminescent converter, wherein the transmitted reflected first light source light may have a third full width at half maximum (FWHM3) downstream of the second luminescent converter. That is, the reflected first light2024PF80342

[0073] 19

[0074] source light, transmitted by the second luminescent converter and escaping from the second converter second major face, may have a third full width at half maximum (FWHM3) downstream of the second luminescent converter. The third full width at half maximum (FWHM3) of the reflected first light source light transmitted by the second luminescent converter may especially be determined by an angular intensity distribution of the reflected first light source light in a cross-section of the reflected first light source light perpendicular to a direction of propagation of the reflected first light source light (downstream of the second luminescent converter). In embodiments, the third full width at half maximum (FWHM3) may be selected from the range of > 10°, such as from the range of > 15°, especially from the range of > 17°. Additionally or alternatively, the third full width at half maximum (FWHM3) may be selected from the range of < 100°, such as from the range of < 80°, especially from the range of < 70°, like from the range of < 60°. Further, in embodiments, FWHM3 > FWHM2 (may apply), such as (FWHM3 - FWHM2) > 5°, especially (FWHM3 - FWHM2) > 10°, like (FWHM3 - FWHM2) > 12°. Additionally or alternatively, in embodiments, (FWHM3 - FWHM2) < 40° (may apply), such as (FWHM3 -FWHM2) < 30°, especially (FWHM3 - FWHM2) < 20°, like (FWHM3 - FWHM2) < 15°. Hence, in specific embodiments, the first light source light may have a first full width at half maximum (FWHM1); the reflected first light source light received at the second converter first major face may have a second full width at half maximum (FWHM2); and the reflected first light source light, transmitted by the second luminescent converter and escaping from the second converter second major face may have a third full width at half maximum (FWHM3) downstream of the second luminescent converter; wherein FWHM3 > FWHM2 and FWHM2 > FWHM1 (may apply). A light generating system wherein the FWHM of a beam of light source light may increase upon moving through the light generating system may facilitate that a solid state light source providing a relatively collimated beam of light source light may be used as the first solid state light source, wherein the relatively collimated beam may be converted into a divergent beam of light source light by the luminescent converters without the need for additional optics.

[0075] As indicated above, the first luminescent and second luminescent converter may comprise one of: (a) a luminescent material in a(n index-matched) matrix material, (b) a ceramic phosphor tile, and (c) a crystalline phosphor tile. A ceramic phosphor tile may comprise a compressed luminescent material powder. Further, a crystalline phosphor tile may comprise a single crystal of a luminescent material. Hence, the first luminescent converter and the second luminescent converter may (each) comprise a luminescent material.2024PF80342

[0076] 20

[0077] Especially, the first luminescent converter may comprise a first luminescent material, and the second luminescent converter may comprise a second luminescent material. Some general embodiments relating to the (first and / or second) luminescent material will be provided next. The term “luminescent material” may especially refer to a material that can convert first radiation, especially one or more of UV radiation, violet radiation, blue radiation, and green radiation, into second radiation. Herein, UV (ultraviolet) may refer to a wavelength selected from the range of 190-380 nm, such as 200-380 nm, though other wavelengths may also be possible. The first radiation and second radiation may have different spectral power distributions, with the second radiation generally having a spectral power distribution at larger wavelengths than the first radiation (i.e., “down-conversion”). In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. Further, IR (infrared) may especially refer to radiation having a wavelength selected from the range of 780-3000 nm, such as 780-2000 nm, e.g. a wavelength of < 1500 nm, like a wavelength of > 900 nm, though other wavelengths may be possible.

[0078] For instance, the luminescent material may be able to convert one or more of UV radiation and blue radiation into visible light. Hence, upon excitation with radiation, the luminescent material may emit radiation. In general, the luminescent material will be a down converter, i.e. radiation with a smaller wavelength is converted into radiation with a larger wavelength (Ux< Um). The term “luminescence” may refer to phosphorescence. Further, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “luminescent material light” or “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and / or fluorescence. The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. Instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art.

[0079] In embodiments, luminescent materials may be selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium. In embodiments, the luminescent material may comprise a divalent europium2024PF80342

[0080] 21

[0081] comprising oxynitride luminescent material. Further, in embodiments, the luminescent material may comprise a divalent europium comprising nitride luminescent material.

[0082] In embodiments, the luminescent material may comprise a luminescent material of the type A₃B₅O₁₂:Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc; and wherein the light source light may comprise blue light source light. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A₃B₅O₁₂ garnets, wherein A comprises at least yttrium (Y) or lutetium (Lu) and wherein B comprises at least aluminum (Al). Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al), with optionally gallium (Ga) and / or scandium (Sc) and / or indium (In) up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of > 90 mole % of Al and < 10 mole % of one or more of Ga, Sc, and In). B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Y₁₋ₓLuₓ)₃B₅O₁₂:Ce, wherein 0 < x < 1. The term “: Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art. In embodiments, such luminescent materials may have a suitable spectral distribution, have a relatively high efficiency, and have a relatively high thermal stability.

[0083] In specific embodiments, the luminescent material may comprise (YxiA’x2Cex3)3(AlyiB’y2)5Oi2. Here, A’ comprises one or more elements selected from the group consisting of lanthanides, and B’ comprises one or more elements selected from the group of Ga, In and Sc, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2. Especially, x3 is selected from the range of 0.001-0.1. Note that in embodiments x2=0. Alternatively or additionally, in embodiments y2=0.2024PF80342

[0084] 22

[0085] In embodiments, the luminescent material may comprise a luminescent material of the type A₃Si₆N₁₁:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y. In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS: Eu2+and / or M₂Si₅N₈:Eu2+and / or MAlSiN₃:Eu2+and / or Ca₂AlSi₃O₂N₅:Eu2+. etc., wherein M comprises one or more of Ba, Sr and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba, Sr, Ca)S: Eu, (Ba, Sr, Ca)AlSiN3: Eu and (Ba, Sr, Ca)2Si5Ns: Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations, as is known to the person skilled in the art. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “: Eu”, indicates that part of the metal ions (indicated by M) is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSiN₃:Eu, the correct formula could be (Ca₀.₉₈Eu₀.₀₂)AlSiN₃.

[0086] The term “luminescent material” herein especially relates to inorganic luminescent materials. Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc.

[0087] In embodiments, the luminescent material may comprise a luminescent material of the type M₁₋ₓLi₃₋₂ᵧAl₁₊₂ᵧ₋zSizO₄₋₄ᵧ₋zN₄ᵧ₊z:Euₓ. Herein, M may comprise one or more of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba), such as especially one or more of Ca, Sr, and Ba. Hence, M₁₋ₓLi₃₋₂ᵧAl₁₊₂ᵧ₋zSizO₄₋₄ᵧ₋zN₄ᵧ₊z:Euₓ may especially refer to (Mg, Ca, Sr, Ba)i-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux. Such a luminescent material may be indicated as an SLA-type phosphor, or SLA phosphor. Luminescent materials of the type Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Euxmay be described in US2021171827A1, which is hereby herein incorporated by reference. In Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux, x may be selected from the range of 0 < x < 0.1, such as from the range of 0.0005 < x < 0.08, especially from the range of 0.001 < x < 0.05. Hence, europium (Eu) may not replace more than 10% of the cation M, and may substantially or only be in the divalent state (Eu2+), as is known to the person skilled in the art. Further, in Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux, y may be selected from the range of 0 < y < 1, such as from the range of 0 < y < 0.75, especially from the range of 0 <y < 0.6. In specific embodiments, y = 0. In Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux, z may be selected from the range of 0 < z < 0.1, such as from the range of 0 < z < 0.07,2024PF80342

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[0089] especially from the range of 0 < z < 0.05. Hence, in embodiments, in an SLA phosphor, SiN may replace A1O to a maximum of 10 mole%. In embodiments, an SLA phosphor may crystallize in a UCr4C4 type crystal structure. Hence, the luminescent material may comprise a luminescent material of the type Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux, wherein M comprises one or more of Ca, Sr, and Ba, wherein 0 < x < 0.04, wherein 0 < y < 1, wherein 0 < z < 0.05, and wherein y + z < 1.

[0090] Further, the luminescent material may comprise a SiAlON phosphor, such as selected from the group comprising (a) Si₁₂₋ₘ₋ₙAlₘ₊ₙOₙN₁₆₋ₙ:Eu2+(α-SiAlON), (b) Si₆₋ₙAlₙOₙN₈₋ₙ:Eu2+, wherein 0 ≤ n ≤ 4.2 (β-SiAlON), and (c) Si2-nAlnOi+nN2-n: Eu2+, wherein 0 < n < 0.2 (O-SiAlON).

[0091] In embodiments, the luminescent material may comprise a tetravalent manganese-comprising luminescent material, i.e., a luminescent material doped with tetravalent manganese. Especially, in embodiments, the luminescent material may comprise a luminescent material of the type M’xM2-2XAXs doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an alkaline cation, and x may be selected from the range of 0-1, wherein A comprises a tetraval ent cation, for instance comprising one or more of silicon and titanium, and wherein X comprises a monovalent anion, at least comprising fluorine. Such luminescent materials may herein also be indicated as “KSiF” or “KSF”, regardless of the composition of M’, M, A, and X. A luminescent material of the type M’XM2-2XAX6 doped with tetravalent manganese is amongst others described in WO2013121355A1, which is herein incorporated by reference. Passages from WO2013121355A1 are also copied herein. In embodiments, the alkaline earth cation M’ may comprise one or more of magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. Further, the alkaline cations M may comprise one or more of sodium (Na), potassium (K) and rubidium (Rb). Optionally, M may (further) comprise one or more of ammonium (NH4+), lithium (Li), and cesium (Cs). In a preferred embodiment, M comprises at least potassium. In yet another embodiment, M comprises at least rubidium. The phrase “wherein M comprises at least potassium” indicates for instance that of all M cations in a mole M’xM2-2XAXs, a fraction comprises K+and an optionally remaining fraction comprises one or more other monovalent (alkaline) cations (see also below). In another preferred embodiment, M comprises at least potassium and rubidium. Optionally, the M’xM2-2XAXe luminescent material has the hexagonal phase. In yet another embodiment, the M’xM2-2XAXs luminescent material has the cubic phase. In an embodiment, a combination of different alkaline cations M may be applied. In yet another embodiment, a2024PF80342

[0092] 24

[0093] combination of different alkaline earth cations M’ may be applied. In yet another embodiment, a combination of one or more alkaline cations M and one or more alkaline earth cations M’ may be applied. For instance, KRbo.5Sro.25AX6 might be applied. As indicated above, x in the formula M’xM2-2xAX6 may be selected from the range of 0-1, especially x < 1. In specific embodiments, x = 0.

[0094] The term “tetravalent manganese” refers to Mn4+. This is a well-known luminescent ion. In the formula as indicated above, part of the tetraval ent cation A (such as Si) is being replaced by manganese. Hence, M’xM2-2xAX6 doped with tetravalent manganese may also be indicated as M’xM2-2xAi-mMnmX6 (or M’xM2-2xAX6: Eu). The mole percentage of manganese, i.e. the percentage it replaces the tetraval ent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12. As manganese replaces part of a host lattice ion and has a specific function, it is also indicated as “dopant” or “activator”. Hence, the hexafluorosilicate is doped or activated with manganese (Mn4+).

[0095] In embodiments, A may comprise a tetravalent cation, and preferably at least comprises silicon. A may optionally (further) comprise one or more of titanium (Ti), germanium (Ge), stannum (Sn) and zinc (Zn). Preferably, at least 80%, even more preferably at least 90%, such as at least 95% of A consists of silicon. In a specific embodiment, M’XM2-2xAXg can also be described as (Ki-r-i-n-c-nh RbrLiiNanCsc(NH4)nh)2AX6, wherein r is in the range of 0-1, wherein l,n,c,nh are each individually preferably in the range of 0-1, preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05, and wherein r+l+n+c+nh is in the range of 0-1, especially 1+n+c+nh < 1, especially < 0.2, preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05. X is preferably fluorine (F). Further, in a specific embodiment, M’XM2-2xAXg can also be described as MgmgCacaSrsrBaba(KkRbrLiiNanCsc(NH4)nh)2AX6, with k, r, 1, n, c, nh each individually being in the range of 0-1, wherein mg, ca, sr, ba are each individually in the range of 0-1, and wherein mg+ca+sr+ba+k+ r+ l+n+c+nh=l. In embodiments, k=l, and the others (mg, ca, sr, ba, r, 1, n, c, nh) are zero.

[0096] As indicated above, X relates to a monovalent anion, but at least comprises fluorine. Other monovalent anions that may optionally be present may be selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I). Preferably, at least 80%, even more preferably at least 90%, such as 95% of X consists of fluorine. Hence, in a specific embodiment, M’xM2-2xAX6 can also be described as M'ₓM₂₋₂ₓA(F₁₋꜀ₗ₋b₋ᵢCl꜀ₗBrbIᵢ)₆, wherein cl,b,i are each individually preferably in the range of 0-0.2, especially in the range of 0-0.1,2024PF80342

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[0098] even more especially in the range of 0-0.05, and wherein cl+b+i < 1, especially < 0.2, preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05. Hence, M’xM2-2xAXe can also be described as (Ki-r-i-n-c-nh RbrLiiNanCsc(NH4)nh)2Sii-m-t-g-s-zrMnmTitGegSnsZrzr(Fi-ci-b-iClciBrbIi)6, with the values for r,l,n,c,nh,m,t,g,s,zr,cl,b,i as indicated above.

[0099] In an embodiment, M’xM2-2xAXe comprises K^SiFe (indicated herein also as KSiF system). In another preferred embodiment, M’xM2-2xAX6 comprises KRbSiFg (herein also indicated as K, Rb system). In specific embodiments, the indication M’xM2-2xAX6 may refer to one or more of (K, Rb)2SiFe: Mn4+, (K, Rb)2TiFe: Mn4+, K₂(Si,Ti)F₆:Mn4+, and Rb₂(Si,Ti)F₆:Mn4+, such as one or more of K₂TiF₆:Mn4+, of K₂SiF₆:Mn4+, and of Rb₂SiF₆:Mn4+. As can be derived from the above, “(Si, Ti)” may indicate one or more of Si and Ti. Hence, in specific embodiments, the luminescent material may comprise one or more of (K,Rb)₂SiF₆:Mn4+and K₂(Si,Ti)F₆:Mn4+. The luminescent material may also be coated, as also described in WO2013121355A1.

[0100] Hence, when M (or A) in chemical formulas refer to n different elements, this may imply that the relevant formula may comprise for the M (or A) position in the formula essentially any permutation of the n different elements. For instance, when M=Ba, Sr, Ca, or when M comprises one or more of Ba, Sr, Ca, i.e. n=3, this may imply that in the formula Ba, Sr, Ca, (BaxSry), (BaxCay), (CaxSry), or (BaxSryCaz), may be available, wherein in general x+y+z=l. Referring to e.g. M’xM2-2xAX6, this may refer to e.g. one or more of K₂SiF₆:Mn4+and of Rb₂SiF₆:Mn4+, or (KₓRbᵧ)₂SiF₆:Mn4+, etc. Referring to (Ba, Sr, Ca)AlSiN3: Eu, this may imply BaAISiNvEu. SrAISiN.vEu. CaAISiNvEu. (BaxSry)AlSiN3: Eu, (BaxCay)AlSiN3: Eu, (CaxSry)AlSiN3: Eu, or (BaxSryCaz)AlSiN3: Eu. Referring to e.g. AsBsOnT'e. wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, this may imply YsBsOn Ce. La3BsOi2: Ce, GdBsOn C e. TbsBsOn Ce. LmBsOn Ce. but also e.g. (Yx, Gdy)3B50i2: Ce, (Yx, Luy)3B50i2: Ce, (Gdx, Luy)3B50i2: Ce, (Yx, Gdy, Luz)3B50i2: Ce, etc. etc., with hereby only limiting for the sake of economy to unary, binary, and ternary examples, though quaternary and higher examples are not excluded herein. Further, indications like “K, Rb” or Ba, Sr, Ca, and similar indications (see also above), may indicate one or more of such elements. Hence, (K,Rb)₂SiF₆:Mn4+, may e.g. refer to K₂SiF₆:Mn4+and of Rb₂SiF₆:Mn4+, or (KₓRbᵧ)₂SiF₆:Mn4+. Also herein in general x+y=l. Hence, when M (or A) may refer to n different elements, with n being at least two, 2n-l permutations may in principle be possible.

[0101] In embodiments, the first luminescent converter may comprise a first luminescent material. The first luminescent material may comprise any (combination) of the2024PF80342

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[0103] luminescent materials indicated above. Especially, the first luminescent material may comprise, such as be, a luminescent material of the type A₃B₅O₁₂:Ce3+. wherein A may comprise at least one of Y, La, Gd, Tb and Lu, and wherein B may comprise at least one of Al, Ga, In and Sc. Hence, in specific embodiments, the first luminescent converter may comprise a first luminescent material; wherein the first luminescent material may be a luminescent material of the type A₃B₅O₁₂:Ce3+, wherein A may comprise at least one of Y, La, Gd, Tb and Lu, and wherein B may comprise at least one of Al, Ga, In and Sc. Such a luminescent material may be especially suited to provide a crystalline phosphor tile (and / or a ceramic phosphor tile). Further, such luminescent material may be relatively thermally stable and efficient.

[0104] In embodiments, the first luminescent material may be configured to convert at least part of the first light source light received by the first luminescent material into first luminescent material light. The first luminescent material light may have a primary first centroid wavelength (Xci,i) selected from the range of 480-600 nm, such as from the range of 490-590 nm, especially from the range of 510-570 nm. Hence, the first luminescent material light may comprise, such as be, one or more of green light and yellow light. In embodiments, the first luminescent converter light may comprise the first luminescent material light. In specific embodiments, the first luminescent converter light may consist of the first luminescent material light. Alternatively, the first luminescent converter may comprise one or more further luminescent materials (optionally compressed together with the first luminescent material to form a ceramic phosphor tile), wherein the first luminescent converter light may consist of the first luminescent material light and the luminescent material light of the one or more further luminescent materials. Yet, especially, relative to a total weight of the first luminescent material and the one or more further luminescent materials, the first luminescent material may be present (in the first luminescent converter) with a weight percentage of > 70%, such as > 80%, especially > 90%, including (essentially) 100%. That is, a luminescent material content of the first luminescent converter may consist for at least 70 wt.%, such as at least 80 wt.%, especially at least 90 wt.%, including (essentially) 100 wt.%, of the first luminescent material. Alternatively, a luminescent material content of the first luminescent converter may consist for at most 98 wt.%, such as at most 95 wt.%, especially at most 90 wt.%, of the first luminescent material. Further, in embodiments, relative to a total weight of the first luminescent converter, the first luminescent material may be present (in the first luminescent converter) with a weight percentage of > 70%, such as > 80%, especially > 90%, including (essentially) 100%. Hence,2024PF80342

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[0106] in embodiments, the first luminescent converter may (essentially) consist of the first luminescent material. In such embodiments, the first luminescent converter may especially comprise, such as be, a ceramic phosphor tile or a crystalline phosphor tile.

[0107] Turning to the second luminescent converter, the second luminescent converter may comprise a second luminescent material. The second luminescent material may comprise any (combination) of the luminescent materials indicated above. Especially, the second luminescent material may comprise, such as be, a luminescent material of the type M’XM2-2XAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises a monovalent cation (such as especially an alkaline cation), wherein x is in the range of 0-1, wherein A comprises a tetraval ent cation, comprising one or more of silicon, titanium, and germanium, and wherein X comprises a monovalent anion, at least comprising fluorine. Additionally or alternatively, the second luminescent material may comprise, such as be, a luminescent material selected from the group of divalent europium comprising nitride luminescent materials and divalent europium comprising oxynitride luminescent materials. Yet, in specific embodiments, the second luminescent converter may comprise a second luminescent material; wherein the second luminescent material may be one or more of: (i) a luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises a monovalent cation, and x is in the range of 0-1, wherein A comprises a tetraval ent cation, comprising one or more of silicon, titanium, and germanium, and wherein X comprises a monovalent anion, at least comprising fluorine, and (ii) a luminescent material selected from the group of divalent europium comprising oxynitride luminescent materials and divalent europium comprising nitride luminescent materials. Such a second luminescent material may be relatively efficient in converter first light source light into second luminescent material light. Further, such a second luminescent material may especially provide red light.

[0108] In embodiments, the second luminescent material may (further) comprise, such as be, a luminescent material of the type MAlSiN₃:Eu2+. wherein M may comprise one or more of Ba, Sr, and Ca (see also above). Further, in embodiments, the second luminescent material may comprise, such as be, an SLA-type phosphor, i.e., a luminescent material of the type Mi-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux, wherein M comprises one or more of Mg, Ca, Sr, and Ba (especially one or more of Ca, Sr, and Ba), wherein 0 < x < 0.04, wherein 0 < y < 1, wherein 0 < z < 0.05, and wherein y + z < 1 (see also above). Additionally or alternatively, the second luminescent material may comprise a luminescent material selected from the group of SiAlON(-type) phosphors, such as selected from the group comprising (a) Sii2-m-2024PF80342

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[0110] ₙAlₘ₊ₙOₙN₁₆₋ₙ:Eu2+, (b) Si₆₋ₙAlₙOₙN₈₋ₙ:Eu2+, wherein 0 ≤ n ≤ 4.2, and (c) Si₂₋ₙAlₙO₁₊ₙN₂₋ₙ:Eu2+, wherein 0 < n < 0.2. Yet, additionally or alternatively, the second luminescent material may comprise, such as be, a luminescent material of the type A₃B₅O₁₂:Ce3+. wherein A may comprise at least one of Y, La, Gd, Tb and Lu, and wherein B may comprise at least one of Al, Ga, In and Sc. Hence, in embodiments, the second luminescent material may be of the same type as the first luminescent material. In specific embodiment, the first luminescent material may be identical to the second luminescent material. Alternatively, the first luminescent material and the second luminescent material may be of the same type, wherein an atomic composition of the first luminescent material and the second luminescent material may differ. For instance, both the first luminescent material and the second luminescent material may be of the type A₃B₅O₁₂:Ce3+. wherein the first luminescent material and the second luminescent material may differ in the atomic composition of A and / or B (e.g., for the first luminescent material A may consist of Lu, and for the second luminescent material A may consist of Y). Hence, in specific embodiments, the first luminescent converter may comprise a first luminescent material, and the second luminescent converter may comprise a second luminescent material, wherein the first luminescent material and the second luminescent material may be of the same type. As certain types of luminescent materials may be more easily provided as a ceramic phosphor tile and / or a crystalline phosphor tile, selecting the first and second luminescent materials to be of the same type (e.g. of the type A₃B₅O₁₂:Ce3+) may facilitate that both the first and second luminescent materials may be relatively easily provided as a ceramic phosphor tile and / or a crystalline phosphor tile.

[0111] In embodiments, the second luminescent material may be configured to convert at least part of the first light source light received by the second luminescent material into second luminescent material light. The second luminescent material light may have a primary second centroid wavelength (Xc2,i) selected from the range of 580-700 nm, such as from the range of 590-690 nm, especially from the range of 600-670 nm, like from the range of 600-660 nm. Hence, the second luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light. In embodiments, the second luminescent converter light may comprise the second luminescent material light. In specific embodiments, the second luminescent converter light may consist of the second luminescent material light. Alternatively, the second luminescent converter may comprise one or more further luminescent materials (optionally compressed together with the second luminescent material to form a ceramic phosphor tile), wherein the second luminescent converter light may consist of the second luminescent material light and the luminescent2024PF80342

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[0113] material light of the one or more further luminescent materials. Yet, especially, relative to a total weight of the second luminescent material and the one or more further luminescent materials, the second luminescent material may be present (in the second luminescent converter) with a weight percentage of > 70%, such as > 80%, especially > 90%, including (essentially) 100%. That is, a luminescent material content of the second luminescent converter may consist for at least 70 wt.%, such as at least 80 wt.%, especially at least 90 wt.%, including (essentially) 100 wt.%, of the second luminescent material. Alternatively, a luminescent material content of the second luminescent converter may consist for at most 98 wt.%, such as at most 95 wt.%, especially at most 90 wt.%, of the second luminescent material. Further, in embodiments, relative to a total weight of the second luminescent converter, the second luminescent material may be present (in the second luminescent converter) with a weight percentage of > 70%, such as > 80%, especially > 90%, including (essentially) 100%. Hence, in embodiments, the second luminescent converter may (essentially) consist of the second luminescent material. In such embodiments, the second luminescent converter may especially comprise, such as be, a ceramic phosphor tile or a crystalline phosphor tile.

[0114] Hence, in embodiments, the first luminescent converter may be configured to generate first luminescent converter light (upon irradiation with first light source light), wherein the first luminescent converter light may comprise the first luminescent material light. Similarly, the second luminescent converter may be configured to generate second luminescent converter light (upon irradiation with first light source light), wherein the second luminescent converter light may comprise the second luminescent material light. Further, in embodiments, the light generating system may be configured to generate system light. The system light may especially comprise the first luminescent converter light transmitted by the second luminescent converter. Further, the system light may comprise the second luminescent converter light (generated by the second luminescent converter). Especially, the system light may have a spectral power distribution, wherein xi% of the spectral power in the wavelength range of 380-780 nm may be provided by the first luminescent converter light, and X2% of the spectral power in the wavelength range of 380-780 nm may be provided by the second luminescent converter light. In embodiments, xi and X2 may be individually selected from the range of > 10%, such as from the range of > 20%, especially from the range of > 30%. Additionally or alternatively, xi and X2 may be individually selected from the range of < 90%, such as from the range of < 80%, especially from the range of < 70%.

[0115] Further, in embodiments, xi + X2 > 60% may apply, such as xi + X2 > 70%, especially xi + X22024PF80342

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[0117] > 80%. Further yet, in embodiments, xi + X2 > 90% may apply, such as xi + X2 > 95%, especially xi + X2 > 98%, like (essentially) xi + X2 = 100%. Yet, alternatively, in embodiments, xi + X2 < 98% may apply, such as xi + X2 < 95%, especially xi + X2 < 90%.

[0118] Hence, in embodiments, the system light may (essentially) consist of the first luminescent converter light and the second luminescent converter light. Alternatively, the system light may comprise the first luminescent converter light, the second luminescent converter light, and a contribution from one or more additional light generating means.

[0119] Especially, in embodiments, the system light may comprise at least part of the reflected first light source light (transmitted by the second luminescent converter). That is, in embodiments, the system light may comprise the first luminescent converter light (transmitted by the second luminescent converter), the second luminescent converter light (generated by the second luminescent converter), and the reflected first light source light (transmitted by the second luminescent converter). Especially, the system light may have a spectral power distribution, wherein > 2%, such as > 5%, especially > 10%, of the spectral power in the wavelength range of 380-780 nm may be provided by the reflected first light source light. Additionally or alternatively, the system light may have a spectral power distribution, wherein < 40%, such as < 30%, especially < 20%, of the spectral power in the wavelength range of 380-780 nm may be provided by the reflected first light source light.

[0120] As indicated above, the (reflected) first light source light may be blue light having a first peak wavelength (λp₁) selected from the range of 380-490 nm. Further, the first luminescent converter light may be green or yellow light having a first centroid wavelength (λc₁) selected from the range of 490-590 nm. Additionally, the second luminescent converter light may be orange or red light having a second centroid wavelength (λc₂) selected from the range of 590-690 nm. Hence, in embodiments, system light comprising (at least part of) the reflected first light source light, the first luminescent converter light, and the second luminescent converter light, may be white light. The term “white light”, and similar terms, herein, is known to the person skilled in the art. It may especially relate to light having a correlated color temperature (CCT) between about 1500 K and 20000 K, such as between 2000 and 20000 K, especially between 2700 and 20000 K, for general lighting especially in the range of about 2000-7000 K, such as in the range of 2700-6500 K. In embodiments, the correlated color temperature (CCT) may especially be within about 20 SDCM (standard deviation of color matching) from the BBL (black body locus), such as within 15 SDCM from the BBL, especially within 10 SDCM from the BBL, like within 5 SDCM from the BBL. Hence, the system light may be white light. Especially, the system light may be white2024PF80342

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[0122] light having a correlated color temperature (CCT) of > 1800 K, such as > 2000 K, especially > 2200 K. Additionally or alternatively, the system light may have a CCT of < 10000 K, such as < 9000 K, especially < 8000 K. Hence, the system light may be white light having a CCT selected from the range of 1800-10000 K, such as from the range of 2000-9000 K, especially from the range of 2200-8000 K. Further, the (white) system light may have a color rendering index (CRI) of at least 60, such as at least 70, especially at least 80. Hence, in specific embodiments, the second luminescent converter may be configured to transmit at least part of the reflected first light source light received by the second luminescent converter; wherein the system light may further comprise at least part of this reflected first light source light; and wherein the system light may be white light having a correlated color temperature selected from the range of 2000-9000 K and a color rendering index of at least 70. Such system light may be suitable for general lighting applications. Further, such system light may have a relatively high blue component (high CCT), thereby allowing the light generating system to be used as a white light source in e.g. an RGB-white lighting system with color tunability.

[0123] Hence, the system light may be white light (having a CCT selected from the range of 2000-9000 K). Alternatively, the system light may be colored light. Especially, the system light may have a color point selected from the CIE 1931 color space. In embodiments, the color point of the system light may be selected from any point in the CIE 1931 color space. Yet, especially, the system light may have a color point within 15 SDCM from the BBL, such as within 10 SDCM from the BBL, especially within 5 SDCM from the BBL. Hence, in specific embodiments, the system light may have a color point within 10 SDCM from the BBL in the CIE 1931 color space. Such system light may especially provide relatively high-quality (white) light.

[0124] As indicated above, the physical separation between the first luminescent converter and the second luminescent converter may define an inter-converter cavity. The inter-converter cavity may have a height corresponding to d₁. Further, the inter-converter cavity may be an open cavity. Especially, the inter-converter cavity may be (at least partially) restricted from the top and bottom by the first luminescent converter and the second luminescent converter, yet may be open at the sides of the inter-converter cavity.

[0125] Alternatively, the inter-converter cavity may be closed at one or more sides of the interconverter cavity (e.g. with one or more reflectors). Yet, especially, at least one side of the inter-converter cavity may be open (wherein the first solid state light source may irradiate the first converter first major face via the open side of the inter-converter cavity).2024PF80342

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[0127] In embodiments, the inter-converter cavity may comprise a gas. The gas may in embodiments be air. Alternatively, the inter-converter cavity may comprise a gas other than air. For instance, the gas may comprise, such as be, an inert gas, such as selected from the group of helium (gas), neon (gas), argon (gas), krypton (gas), xenon (gas), radon (gas), and nitrogen (gas). In specific embodiments, the gas may be an inert gas. Alternatively, the gas may comprise (a mixture of) an inert gas and air. Further, in embodiments, the gas may comprise a thermally conductive gas. Hence, in specific embodiments, the inter-converter cavity may comprise a gas, wherein the gas may comprise one or more of an inert gas and a thermally conductive gas. The thermally conductive gas may comprise one or more of helium (gas), hydrogen (gas), neon (gas), and methane (gas), such as especially one or more of helium and hydrogen. In embodiments, the gas may be a thermally conductive gas (e.g. helium). Alternatively, the gas may comprise a thermally conductive gas (e.g. hydrogen) in a carrier gas (e.g. air or an inert gas such as nitrogen). In embodiments, the (thermally conductive) gas may have a thermal conductivity (at 22 °C and a pressure of 1 bar) selected from the range of > 0.06 W*m'1*K’1, such as from the range of > 0.08 W*m-1*K-1, especially from the range of > 0.1 W*m-1*K-1. Additionally or alternatively, the (thermally conductive) gas may have a thermal conductivity (at 22 °C and a pressure of 1 bar) selected from the range of < 0.25 W*m-1*K-1, such as from the range of < 0.2 W*m-1*K-1, especially from the range of < 0.18 W*m-1*K-1. Hence, in specific embodiments, the inter-converter cavity may comprise a gas other than air. Such a gas may especially have a higher thermal conductivity than air, thereby improving the thermal management of the light generating system.

[0128] Additionally or alternatively, such a gas may have a lower reactivity (i.e., be more inert) than air, thereby improving the durability of the light generating system.

[0129] In embodiments, the inter-converter cavity may be a closed cavity, wherein the (closed) inter-converter cavity comprises the (inert and / or thermally conductive) gas.

[0130] Alternatively, the inter-converter cavity may be an open cavity, wherein at least the part of the light generating system comprising the inter-converter cavity may be configured in a gastight enclosure (e.g. a gas-tight housing), and wherein the gas-tight enclosure may comprise the (inert and / or thermally conductive) gas.

[0131] Additionally or alternatively, the light generating system may comprise a light transparent body. Herein, the term “light transparent” indicates the material may be (specular) transmissive, such as transparent, for one or more wavelengths selected from the range of 190-1500 nm, such as from the range of 200-1000 nm, especially from the range of 380-780 nm (i.e. visible light). In embodiments, the light transparent body may comprise,2024PF80342

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[0133] such as consist of, a light transparent material. The light transparent material may comprise one or more materials selected from the group comprising glass, polycarbonate (PC), polyethylene (PE), polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET), (clear) polyvinyl chloride (PVC), cyclic olefin copolymers (COC), fluorinated ethylene propylene (FEP), styrene methyl methacrylate (SMMA), polysiloxanes, poly(methyl methacrylate) (PMMA), fused silica, and a light transparent sapphire (crystal). Especially, the light transparent body may comprise (a light transparent material selected from the group of) glass, PC, polysiloxanes, and a light transparent sapphire (crystal). Hence, in specific embodiments, the light transparent body may comprise a light transparent sapphire. Sapphire may be especially transmissive for light. Further, sapphire may have a relatively high thermal conductivity, thereby improving the thermal management of the light generating system.

[0134] The light transparent body may be configured in the inter-converter cavity. Further, the light transparent body may be configured in physical contact with the first luminescent converter, such as be placed on (and / or supported by) the first luminescent converter. Additionally or alternatively, the light transparent body may be configured in physical contact with the second luminescent converter. Hence, in embodiments, the light transparent body may have a height of d₁. In embodiments, the light transparent body may be configured to cover at least part of (a surface area of) the first converter first major face. Especially, the light transparent body may be configured to cover > 60%, such as > 70%, especially > 80%, like > 90%, including (essentially) 100%, of (a surface area of) the first converter first major face. Alternatively, the light transparent body may be configured to cover < 98%, such as < 95%, especially < 90%, of (a surface area of) the first converter first major face. Further, the light transparent body may be configured to cover at least part of (a surface area of) the second converter first major face (configured facing the first converter first major face). Especially, the light transparent body may be configured to cover > 60%, such as > 70%, especially > 80%, like > 90%, including (essentially) 100%, of (a surface area of) the second converter first major face. Alternatively, the light transparent body may be configured to cover < 98%, such as < 95%, especially < 90%, of (a surface area of) the second converter first major face. Hence, in specific embodiments, the light transparent body may be configured to span across (essentially) the full inter-converter cavity.

[0135] As indicated above, the first optical path (of the first light source light) may intersect at least part of the inter-converter cavity. Hence, in embodiments, the first optical path may intersect the light transparent body. Further, in embodiments, the first luminescent converter may be configured to reflect at least part of the first light source light (as reflected2024PF80342

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[0137] light source light) to the second luminescent converter via the light transparent body. That is, at least part of the reflected first light source light may be transmitted (from the first luminescent converter) through the light transparent body towards the second luminescent converter. Additionally, at least part of the first luminescent converter light may be transmitted towards the second luminescent converter via (or through) the light transparent body. Hence, in specific embodiments, the light generating system may comprise a light transparent body, wherein the light transparent body may be configured in the inter-converter cavity, wherein the light transparent body may be configured in physical contact with the first luminescent converter and the second luminescent converter, wherein the first optical path may intersect the light transparent body, and wherein at least part of the reflected first light source light may be transmitted through the light transparent body towards the second luminescent converter. Such a light transparent body may provide thermal management for the first luminescent converter and the second luminescent converter. Further, such a light transparent body may reduce surface scattering at the first converter first major face and / or at the second converter first major face, thereby improving the efficiency of the light generating system.

[0138] In embodiments, the light transparent body may be thermally conductive. Especially, the light transparent body may have a thermal conductivity (at 22 °C and a pressure of 1 bar) selected from the range of > 20 W*m-1*K-1, such as from the range of > 30 W*m'1*K’1, especially from the range of> 40 W*m'1*K’1. Additionally or alternatively, the light transparent body may have a thermal conductivity (at 22 °C and a pressure of 1 bar) selected from the range of < 120 W*m'1*K’1, such as from the range of < 100 W*m-1*K-1, especially from the range of < 80 W*m-1*K-1. In embodiments, the light transparent body may be configured in thermal contact with the first luminescent converter. Additionally or alternatively, the light transparent body may be configured in thermal contact with the second luminescent converter. An element may be considered in “thermal contact” with another element if it can exchange energy through the process of heat. Hence, the elements may be thermally coupled. In embodiments, thermal contact can be achieved by physical contact. In embodiments, the light transparent body may thus be configured in physical and thermal contact with the first luminescent converter and the second luminescent converter. Hence, in specific embodiments, the light transparent body may be thermally conductive (wherein the light transparent body may be configured in thermal contact with the first luminescent converter and the second luminescent converter). Such a light transparent body may especially provide thermal management for the first and second luminescent converter.2024PF80342

[0139] 35

[0140] The light transparent body may comprise a transparent body first face configured in physical contact with the first luminescent converter. Additionally or alternatively, the light transparent body may comprise a transparent body second face configured (opposite the transparent body first face and) in physical contact with the second luminescent converter. Further, the light transparent body may comprise one or more transparent body side faces. The one or more transparent body side faces may be configured bridging the transparent body first face and the transparent body second face. Hence, the one or more transparent body side faces may be configured bridging the inter-converter cavity between the first luminescent converter and the second luminescent converter. In embodiments, at least one of the one or more transparent body side faces may be configured at a smallest side angle (y) with the first converter first major face. Further, in embodiments, all of the one or more transparent body side faces may be configured at a smallest side angle (y) with the first converter first major face. The smallest side angle (y) may be selected from the range of > 75-α₁, such as from the range of > 80-α₁, especially from the range of > 85-α₁. Additionally or alternatively, the smallest side angle (y) may be selected from the range of < 105-α₁, such as from the range of < 100-α₁, especially from the range of < 95-α₁. Hence, in embodiments, (75-α₁) < y < (105-α₁) may apply, such as (80-α₁) < y < (100-α₁), especially (85-α₁) < y < (95-α₁). Hence, the at least one of the one or more transparent body side faces may be configured slanted. Especially, in embodiments, (at least) one of the one or more transparent body side faces may be configured facing the first solid state light source, wherein said transparent body side face(s) may be configured slanted towards a (geometrical) center of the light transparent body with respect to the first converter first major face. Hence, said transparent body side face(s) may be configured (essentially) perpendicular to the first optical path. In embodiments, the light transparent body may comprise a second transparent body side face configured opposite the (at least one) transparent body sides face(s) configured facing the first solid state light source. In embodiments, said second transparent body side face may be slanted in a different, especially opposite, direction from the (at least one) transparent body sides face(s) configured facing the first solid state light source. Hence, the light transparent body may have a tapering shape (in a cross-section perpendicular to the first converter first major face and parallel to the first optical path). Especially, the light transparent body may taper towards the second luminescent converter. Hence, in specific embodiment, the light transparent body may comprise one or more transparent body side faces, wherein the one or more transparent body side faces may be configured bridging the inter-converter cavity between the first luminescent converter and the second luminescent2024PF80342

[0141] 36

[0142] converter; wherein at least one of the one or more transparent body side faces may be configured at a smallest side angle (y) with the first converter first major face; wherein (80-α₁) < y < (100-α₁); and wherein the light transparent body may taper towards the second luminescent converter. Such a light transparent body may reduce the amount of first light source light refracted and / or reflected at the (at least) one transparent body side face configured intersecting the first optical path.

[0143] As indicated above, the light generating system may further comprise a first thermally conductive body. The first thermally conductive body may especially comprise, such as consist of, a thermally conductive material. The thermally conductive material may have a thermal conductivity (at 22 °C and a pressure of 1 bar) selected from the range of > 20 W*m'1*K’1, such as from the range of > 30 W*m-1*K-1, especially from the range of > 50 W*m-1*K-1, like from the range of > 100 W*m-1*K-1, such as from the range of > 200 W*m-1*K-1. Further, in embodiments, the thermally conductive material may comprise one or more of copper, aluminum, silver, gold, silicon carbide, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, a silicon carbide composite, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, diamond, magnesium, aluminum oxide, and graphite. In embodiments, the first thermally conductive body may comprise, such as be, one or more of a heatsink, a heat spreader, and a two-phase cooling device.

[0144] The first thermally conductive body may be configured in thermal contact with the first luminescent converter via the first converter second major face. Especially, the first luminescent converter (especially the first converter first major face) may be configured mounted on (and / or supported by) the first thermally conductive body. As indicated above, the first luminescent converter may be configured in the reflective mode, wherein (i) the first converter second major face may comprise a reflective coating, and / or (ii) the first converter second major face may be configured in physical contact with a reflective substrate. In embodiments, the first thermally conductive body may comprise, such as be, the reflective substrate. Alternatively, the first thermally conductive body may comprise a reflector (e.g. a reflective coating), wherein the first converter second major face may be configured in physical contact with the reflector of the first thermally conductive body. Hence, the first thermally conductive body may be reflective for first light source light and first luminescent converter light. Especially, the first thermally conductive body may be configured to reflect > 80%, such as > 90%, especially > 95%, like > 98%, including (essentially) 100%, of the first light source light and first luminescent converter light received by the first thermally2024PF80342

[0145] 37

[0146] conductive body. Hence, in specific embodiments, the first thermally conductive body may be reflective for first light source light and first luminescent converter light. Such a first thermally conductive body may provide both thermal management and a reflective coating for the first luminescent converter. Further, such a first thermally conductive body may reflect any first light source light and first luminescent converter light received by the first thermally conductive body towards the second luminescent converter, thereby improving the efficiency of the light generating system.

[0147] The light generating system may further comprise a second thermally conductive body. In embodiments, the second thermally conductive body may be configured separate from the first thermally conductive body. Alternatively, the first thermally conductive body may be configured in physical (and thermal) contact with the second thermally conductive body. Further, in embodiments, the light generating system may comprise a thermally conductive element, wherein the thermally conductive element may comprise the first thermally conductive body and the second thermally conductive body. The second thermally conductive body may comprise a thermally conductive material, such as a thermally conductive material selected from the thermally conductive materials provided above. Further, the second thermally conductive body may be configured in the thermal (and physical) contact with the second luminescent converter. Especially, the second thermally conductive body may be configured in thermal contact with the second luminescent converter at (or via) one or more of: (a) at least part of the second converter first major face; (b) at least part of the second converter second major face; and (c) at least part of the one or more second converter side faces. Hence, in specific embodiments, the second luminescent converter may comprise: (i) a second converter first major face configured facing the first luminescent converter; (ii) a second converter second major face configured opposite the second converter first major face; and (iii) one or more second converter side faces configured bridging the second converter first major face and the second converter second major face; and the light generating system may comprise a second thermally conductive body, wherein the second thermally conductive body may be configured in thermal contact with the second luminescent converter at one or more of: (a) at least part of the second converter first major face; (b) at least part of the second converter second major face; and (c) at least part of the one or more second converter side faces. Such a second thermally conductive body may provide thermal management for the second luminescent converter, thereby improving the lifetime of the second luminescent converter (such as especially of the second luminescent material).2024PF80342

[0148] 38

[0149] Hence, the second thermally conductive body may be configured in thermal contact with the second luminescent converter at one or more of (at least part of) the second converter first major face and (at least part of) the second converter second major face. In such embodiments, the second thermally conductive body may especially be light transparent. That is, the second thermally conductive body may be configured to transmit > 80%, such as > 90%, especially > 95%, like > 98%, including (essentially) 100%, of the reflected first light source light, transmitted first luminescent converter light, and second luminescent converter light received by the first thermally conductive body. Hence, in specific embodiments, the second thermally conductive body may be light transparent, wherein the second thermally conductive body may be configured in thermal contact with the second luminescent converter at one or more of the second converter first major face and the second converter second major face. As the second converter first major face and the second converter second major face may (each) have a relatively larger surface area than the second converter side faces, such a second thermally conductive body may provide improved thermal management.

[0150] In embodiments, the light generating system may further comprise a second solid state light source. The second solid state light source may be selected from the group comprising an LED, a laser diode, a superluminescent diode, and a (stacked) multi -junction light emitting diode, though other options may also be possible (see below). Especially, the second solid state light source may comprise, such as be, one or more of a laser light source and a superluminescent diode. Further, the second solid state light source may be configured to generate second light source light. The second light source light may especially have a second peak wavelength ( / .p2) selected from the range of 370-500 nm, such as from the range of 380-490 nm, especially from the range of 400-490 nm. Further, the second peak wavelength ( / .p2) may be selected from the range of 420-490 nm, such as from the range of 430-490 nm, especially from the range of 440-465 nm. Hence, the second light source light may be one of violet light and blue light, such as especially blue light.

[0151] In embodiments, the second solid state light source light may be configured to irradiate the first converter first major face. Especially, the second solid state light source may irradiate the first converter first major face via a second optical path between the second solid state light source and the first luminescent converter. In embodiments, a projection of the second optical path on the first converter first major face may be configured at an angle (P) with respect to a projection of the first optical path on the first converter first major face. In embodiments, the angle ( ) may be selected from the range of 20-180°, such as from the2024PF80342

[0152] 39

[0153] range of 50-180°, especially from the range of 90-180°, like from the range of 120-180°. Herein, an angle (P) of 180° may indicate that (the projection of) the first optical path may be configured on a straight line with (the projection of) the second optical path, wherein a propagation direction of the first light source light along the first optical path may be opposite from a propagation direction of the second light source light along the second optical path. In embodiments, the second optical path may intersect at least part of the interconverter cavity. That is, the second optical path may be at least partially configured between the first luminescent converter and the second luminescent converter. Further, the second optical path may pass by (and not intersect) the second luminescent converter. Hence, in embodiments, the second optical path may enter the inter-converter cavity from a side of the inter-converter cavity (and be incident on the first luminescent converter). Alternatively, the second optical path may enter the inter-converter cavity from a top of the inter-converter cavity, wherein the second luminescent converter may be configured staggered with respect to the first luminescent converter, such that the second optical path passes by (and does not intersect) the second luminescent converter.

[0154] In embodiments, the first luminescent converter may be configured to convert (at least) part of the second light source light received by the first luminescent converter into first luminescent converter light. Especially, the first luminescent converter may be configured to convert > 80%, such as > 90%, especially > 95%, like > 97%, of the second light source light received by the first luminescent converter into first luminescent converter light. Additionally or alternatively, the first luminescent converter may be configured to convert < 99.5%, such as < 99%, especially < 98%, of the second light source light received by the first luminescent converter into first luminescent converter light. Further, the first luminescent converter may be configured to reflect at least part of the second light source light received by the first luminescent converter to the second luminescent converter as reflected second light source light. The first luminescent converter may especially reflect the reflected second light source light to the second luminescent converter via the inter-converter cavity. In embodiments, the first luminescent converter may be configured to reflect < 20%, such as < 10%, especially < 5%, like < 3%, of the second light source light received by the first luminescent converter to the second luminescent converter (via the inter-converter cavity) as reflected second light source light. Additionally or alternatively, the first luminescent converter may be configured to reflect > 0.5%, such as > 1%, especially > 2%, of the second light source light received by the first luminescent converter to the second luminescent converter (via the inter-converter cavity) as reflected second light source light.2024PF80342

[0155] 40

[0156] In embodiments, the first luminescent converter may be configured to specularly reflect the at least part of the second light source light received by the first luminescent converter. Alternatively, the at least part of the second light source light reflected at the first luminescent converter (as reflected second light source light) may be (at least partially) scattered at the first luminescent converter. Especially, in embodiments, the first luminescent converter may be configured to provide reflected second light source light, wherein the reflected second light source light may have a FWHM being 1-15°, such as 2-10°, especially 3-5°, larger than a FWHM of the second light source light incident on the first converter first major face.

[0157] Hence, the first luminescent converter may be configured to reflect at least part of the second light source light to the second luminescent converter as reflected second light source light. The second luminescent converter may be configured to convert at least part of the reflected second light source light received by the second luminescent converter into second luminescent converter light. Especially, the second luminescent converter may be configured to convert > 50%, such as > 60%, especially > 70%, of the reflected second light source light received by the second luminescent converter into second luminescent converter light. Further, in embodiments, the second luminescent converter may be configured to convert > 80%, such as > 90%, especially > 95%, including (essentially) 100%, of the reflected second light source light received by the second luminescent converter into second luminescent converter light. Additionally or alternatively, the second luminescent converter may be configured to transmit at least part of the reflected second light source light received by the second luminescent converter. Hence, in embodiments, the second luminescent converter may be configured to convert < 95%, such as < 90%, especially < 80%, of the reflected second light source light received by the second luminescent converter into second luminescent converter light. Further, the second luminescent converter may be configured to transmit > 5%, such as > 10%, especially > 20%, of the reflected second light source light received by the second luminescent converter. Additionally or alternatively, the second luminescent converter may be configured to transmit < 50%, such as < 40%, especially < 30%, of the reflected second light source light received by the second luminescent converter. In embodiments, the second luminescent converter may at least partially scatter the reflected second light source light transmitted by the second luminescent converter. Especially, in embodiments, the second luminescent converter may be configured to transmit at least part of the reflected second light source light, wherein the transmitted reflected second light source2024PF80342

[0158] 41

[0159] light may have a FWHM being 2-40°, such as 4-30°, especially 6-20°, larger than a FWHM of the reflected second light source light incident on the second converter first major face.

[0160] In alternative embodiments, the second solid state light source may be configured to irradiate the second converter second major face. Especially, the second solid state light source may irradiate the second converter second major face via a second optical path between the second solid state light source and the second luminescent converter. In such embodiments, a projection of the second optical path on the second converter first major face may be configured at an angle (P) with respect to a projection of the first optical path on the second converter first major face, wherein the angle (P) may be selected from the range of 20-180°, such as from the range of 50-180°, especially from the range of 90-180°, like from the range of 120-180° (and wherein an angle (P) of 180° may have the same meaning as indicated above). Further, in such embodiments, the second luminescent converter may be configured to convert (at least) part of the second light source light received by the second luminescent converter. Especially, the second luminescent converter may be configured to convert > 80%, such as > 90%, especially > 95%, like > 97%, of the second light source light received by the second luminescent converter into second luminescent converter light.

[0161] Additionally or alternatively, the second luminescent converter may be configured to convert < 99.5%, such as < 99%, especially < 98%, of the second light source light received by the second luminescent converter into second luminescent converter light. Further, in embodiments, the second luminescent converter may be configured to reflect (at least part of) the second light source light received by the second luminescent converter as reflected second light source light. In such embodiments, the second luminescent converter may be configured to convert < 50%, such as < 40%, especially < 30%, of the second light source light received by the second luminescent converter into second luminescent converter light. Further, in such embodiments, the second luminescent converter may be configured to convert < 20%, such as < 10%, especially < 5%, including (essentially) 0%, of the second light source light received by the second luminescent converter into second luminescent converter light.

[0162] Hence, the second luminescent converter may be configured to reflect at least part of the second light source light received by the second luminescent converter as reflected second light source light. In embodiments, the second luminescent converter may be configured to reflect < 20%, such as < 10%, especially < 5%, like < 3%, of the second light source light received by the second luminescent converter as reflected second light source light. Additionally or alternatively, the second luminescent converter may be configured to2024PF80342

[0163] 42

[0164] reflect > 0.5%, such as > 1%, especially > 2%, of the second light source light received by the second luminescent converter as reflected second light source light. Further, in embodiments, the second luminescent converter may be configured to reflect > 80%, such as > 90%, especially > 95%, including (essentially) 100%, of the second light source light received by the second luminescent converter as reflected second light source light. Yet, in embodiments, the second luminescent converter may be configured to reflect < 99.5%, such as < 99%, especially < 98%, like < 95%, of the second light source light received by the second luminescent converter as reflected second light source light. Hence, in specific embodiments, the light generating system may comprise a second solid state light source, wherein the second solid state light source may comprise one or more of a laser light source and a superluminescent diode; wherein the second solid state light source may be configured to generate second light source light; and wherein one of the following applies: (A) the second solid state light source may be configured to irradiate the first converter first major face via a second optical path between the second solid state light source and the first luminescent converter, wherein the second optical path may intersect at least part of the interconverter cavity and passes by the second luminescent converter, wherein the first luminescent converter may be configured to (i) convert part of the second light source light received by the first luminescent converter into first luminescent converter light, and (ii) reflect at least part of the second light source light received by the first luminescent converter as reflected second light source light to the second luminescent converter; wherein the second luminescent converter may be configured to convert at least part of the reflected second light source light received by the second luminescent converter into second luminescent converter light; and (B) the second solid state light source may be configured to irradiate the second converter second major face via a second optical path between the second solid state light source and the second luminescent converter, wherein the second luminescent converter may be configured to (i) convert part of the second light source light received by the second luminescent converter into second luminescent converter light, and (ii) reflect at least part of the second light source light received by the second luminescent converter as reflected second light source light. A light generating system comprising a second solid state light source may facilitate providing system light having a higher intensity. Further, a light generating system wherein the second solid state light source is configured to irradiate the second converter second major face may facilitate selectively irradiation of the second luminescent converter.2024PF80342

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[0166] In embodiments, the second solid state light source may irradiate the one of the first converter first major face and the second converter second major face under an angle. Especially, the second optical path may be configured at a (smallest) second angle (α₂) with one (or more) of the first converter first major face and the second converter second major face. In embodiments, the second optical path may be incident on the first converter first major face, wherein the second optical path may have the (smallest) second angle (α₂) with the first converter first major face. Alternatively, the second optical path may be incident on the second converter second major face, wherein the second optical path may have the (smallest) second angle (α₂) with the second converter second major face. In embodiments, the (smallest) second angle (α₂) may be selected from the range of ≥ 10°, such as from the range of > 20°, especially from the range of > 30°, like from the range of > 40°. Additionally or alternatively, the (smallest) second angle (α₂) may be selected from the range of ≤ 80°, such as from the range of < 70°, especially from the range of < 60°, like from the range of < 50°. Hence, in embodiments, 10° ≤ α₂ ≤ 80° (may apply), such as 20° ≤ α₂ ≤ 70°, especially 30° ≤ α₂ ≤ 60°, like 40° ≤ α₂ ≤ 50°. That is, the second optical path may be configured at a (smallest) angle (α₂N) with respect to a (surface) normal to the first converter first major face and / or second converter second major face of 80° ≥ α₂N ≥ 10°, such as 70° ≥ α₂N ≥ 20°, especially 60° ≥ α₂N ≥ 30°, like 50° ≥ α₂N ≥ 40°. Further, in embodiments, α₂ = α₁ may apply. Alternatively, |α₂ − α₁| ≥ 1° may apply, such as |α₂ − α₁| ≥ 5°, especially |α₂ − α₁| ≥ 10°. Additionally or alternatively, |α₂ − α₁| ≤ 70° may apply, such as |α₂ − α₁| ≤ 50°, especially |α₂ − α₁| ≤ 30°. Hence, in specific embodiments, the second optical path may be configured at a second angle (α₂) with one of the first converter first major face and the second converter second major face; wherein 20° ≤ α₂ ≤ 70°. Such a (smallest) second angle (α₂) may facilitate that at least part of the second light source light may be reflected by the first luminescent converter or the second luminescent converter. Yet, such a (smallest) second angle (α₂) may facilitate that at least part of the second light source light may be converted by the first luminescent converter or the second luminescent converter.

[0167] As indicated above, the second luminescent converter may be configured to transmit at least part of the reflected second light source light received by the second luminescent converter. Alternatively, the second luminescent converter may be configured to reflect at least part of the second light source light received by the second luminescent converter as reflected second light source light. Hence, in embodiments, the system light may comprise at least part of the reflected second light source light. Especially, the system light may have a spectral power distribution, wherein > 2%, such as > 5%, especially > 10%, of2024PF80342

[0168] 44

[0169] the spectral power in the wavelength range of 380-780 nm may be provided by the reflected second light source light. Additionally or alternatively, the system light may have a spectral power distribution, wherein < 40%, such as < 30%, especially < 20%, of the spectral power in the wavelength range of 380-780 nm may be provided by the reflected second light source light. Hence, in specific embodiments, the system light may comprise at least part of the reflected second light source light. Such system light may especially have a larger blue component, thereby providing (white) system light having a higher CCT.

[0170] As indicated above, the light generating system comprising the second solid state light source may facilitate selectively irradiating (only) the second luminescent converter (with the second solid state light source, wherein the second optical path is between the second solid state light source and the second luminescent converter). In such embodiments, the light generating system may comprise a control system. The control system may be configured to individually control the first solid state light source and the second solid state light source. Especially, the control system may be configured to individually control an intensity of the first light source light and the second light source light. The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein the term “controlling” and similar terms may include imposing behavior on an element and / or monitoring the element. The controlling of the element can be done with a control system. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. The control system and element may not be physically coupled. Control can be done via wired and / or wireless control. A control system may comprise or may be functionally coupled to a user interface. The control system may also be configured to receive and execute instructions from a remote control. The control system may be controlled via an App on a device, such as a portable device. In such embodiments the control system of the lighting system may be a slave control system. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology. The control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and / or a predetermined time scheme.

[0171] As indicated above, the first solid state light source and the second solid state light source may (each) comprise a laser light source and / or a superluminescent diode, though other options may be possible. Here below, some general embodiments related to the2024PF80342

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[0173] solid state light sources are provided. The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source may comprise an LED. The term “light source” may also relate to a plurality of (essentially identical or different) light sources, such as 2-2000 (LED) light sources. The phrase “different light sources”, and similar phrases, may refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrase “identical light sources”, and similar phrases, may refer to a plurality of solid-state light sources selected from the same bin.

[0174] Hence, the term LED may also refer to a plurality of LEDs. Further, the term “light source” may also refer to a so-called chip-on-board (CoB) light source. The term “CoB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light sources may be configured on the same substrate. In embodiments, a CoB is a multi LED chip configured together as a single lighting module.

[0175] The term “light source” may also refer to a chip scale package (CSP) and / or a chip scale packaged (CSP) LED. A CSP may comprise a single solid state die (such as a LED) with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g.

[0176] 0.2-2 mm. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs, such as especially micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially refers to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 μm – 1 mm. Herein, the term p size or micro LED especially refers to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 μm and smaller.

[0177] The light source may have a light escape surface. For LEDs it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the resin. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source.

[0178] The term “light source” may refer to a semiconductor light-emitting device, such as an LED, a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode2024PF80342

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[0180] (VCSELs), an edge emitting laser, etc. The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In an embodiment, the light source comprises a LED. The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). Especially, the term “solid state light source” may refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, a superluminescent diode, or a multi-junction diode.

[0181] The light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise a LED with on-chip optics. The light source may comprise pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering). In embodiments, the (solid state) light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED. Such a light source, which may not comprise a luminescent material, may be indicated as a direct-color LED (dc-LED). Alternatively, the (solid state) light source may be configured to provide primary radiation, wherein at least part of the primary radiation may be converted into secondary radiation (e.g. by a luminescent material). Such a light source may especially be indicated as a phosphor converted LED or pc-LED. Hence, in embodiments, the light source may be a dc-LED. Alternatively, the light source may be a pc-LED. Hence, the term “light source” may refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more optics, like a lens, a collimator. In embodiments, the term “light source” may also refer to a combination of a light source, like an LED, and an optical filter, which may change the spectral power distribution of the light generated by the light source. In specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED or multi-junction (light emitting) diode. The light source may especially be configured to generate light source light having an optical axis (O), (a beam shape,) and a spectral power distribution. The light source light may in embodiments comprise one or more bands, having band widths as known for lasers.

[0182] The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the wavelength range of 200-2000 nm, such as from the wavelength range of 300-1500 nm. The term “laser”2024PF80342

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[0184] especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. Especially, the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, may refer to a laser diode (or diode laser). Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of a semiconductor laser diodes, such as GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc. The term “solid state material laser”, and similar terms, may thus refer to a solid state laser like based on a crystalline or glass body dopes with ions, like transition metal ions and / or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, etc.

[0185] In embodiments, the term “laser light source” may also refer to a plurality of (different or identical) laser light sources. In specific embodiments, the term “laser light source” may refer to a plurality N of (identical) laser light sources. In embodiments, N>2, such as N>5, especially N>8. In this way, a higher brightness (of the laser light) may be obtained. Laser light sources may be arranged in a laser bank. The laser bank may comprise heat sinking and / or optics (e.g. a lens to collimate the laser light). Hence, in embodiments lasers in a laser bank (or “laser array bank”) may share the same optics.

[0186] The laser light source may be configured to generate laser light source light (or “laser light”). The light source light may essentially consist of the laser light source light. The light source light may also comprise laser light source light of two or more (different or identical) laser light sources. For instance, the laser light source light of two or more (different or identical) laser light sources may be coupled into a light guide, to provide a single beam of light comprising the laser light source light of the two or more (different or identical) laser light sources. The light source light may thus be collimated (laser) light source light. The laser light source light may comprise one or more bands, having band widths as known for lasers. In embodiments, the band(s) may be relatively sharp line(s), such as having full width half maximum (FWHM) in the range of <20 nm at RT, such as <10 nm. Hence, the light source light may have a spectral power distribution (intensity on an energy scale as function of the wavelength) which may comprise one or more (narrow) bands. The beams (of light source light) may be focused or collimated beams of (laser) light source light. The term “focused” may especially refer to converging to a small spot. Focusing (of the laser light source light) may be executed with one or more optics, such as especially two (focusing) lenses. Collimation may be executed with one or more (other) optics, like2024PF80342

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[0188] collimation elements, such as lenses and / or parabolic mirrors. In embodiments, the beam of (laser) light source light may be relatively highly collimated, such as in embodiments <2° (FWHM), more especially <1° (FWHM), most especially <0.5° (FWHM).

[0189] In embodiments, the light generating system may be configured as a surfacemounted device (SMD). Alternatively, the light generating system may comprise a surfacemounted device (SMD). The term “surface-mounted device” is known to the person skilled in the art, and may refer to a device which may be mounted (e.g. by soldering) directly onto a surface of a printed circuit board (PCB). In embodiments, the surface-mounted device (SMD) of the light generating system may comprise the first solid state light source. Further, the SMD of the light generating system may comprise the first luminescent converter and the second luminescent converter. Optionally, the SMD of the light generating system may further comprise the second solid state light source. Hence, in specific embodiments, the light generating system may comprise a surface-mounted device; wherein the surface-mounted device may comprise the first solid state light source, the first luminescent converter, and the second luminescent converter; wherein the surface-mounted device may optionally further comprise the second solid state light source. Such an SMD may be relatively easy to install onto a PCB. Further, such a SMD may be relatively compact.

[0190] In embodiments, the SMD (of the light generating system) may further comprise the first thermally conductive body. Additionally or alternatively, the SMD may comprise the light transparent body. Additionally or alternatively, the SMD may comprise the second thermally conductive body. Hence, in specific embodiments, the surface-mounted device may comprise one or more of: (i) the first thermally conductive body, (ii) the light transparent body, and (iii) the second thermally conductive body. Such an SMD may provide improved thermal management for the light generating system.

[0191] Further, in embodiments, the light generating system may comprise one or more optical elements. The one or more optical elements may be selected from the group comprising a lens, a diffuser, a wave guide, a beam-shaping element, a filter, etc. Especially, in embodiments, the light generating system may comprise a lens. The lens may be configured downstream of the first luminescent converter and the second luminescent converter. Further, the lens may be configured to adjust an angular intensity distribution of the system light. Especially, the lens may be configured to reduce a FWHM (in the angular intensity distribution) of the system light. Hence, in specific embodiments, the lens may be a collimator lens. Further, the lens may be configured to provide a collimated beam of system light (upon irradiation with (a divergent beam of) system light). That is, the lens may be2024PF80342

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[0193] configured to collimate (a beam of) system light received by the lens. Hence, in specific embodiments, the light generating system may comprise a lens, wherein the lens may be configured downstream of the first luminescent converter and the second luminescent converter, and wherein the lens may be configured to collimate the system light received by the lens. Such a light generating system may especially provide a collimated beam of system light.

[0194] The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems (e.g. a torch), automotive lighting devices, stage-lighting devices, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

[0195] In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. The lamp may be a portable lamp, such as a torch or a search lighting device. In yet a further aspect, the invention also provides a projector device comprising the light generating system as defined herein. Especially, a projector device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projector device may include one or more light generating systems such as described herein. Further, the invention may provide one or more of a disinfection device, a photochemical reactor, an automotive lighting device, and an optical wireless communication device, comprising the light generating system as defined herein. Further, the invention may provide a lighting fixture, comprising the light generating system as defined herein. The lighting fixture may be e.g. be a chandelier, yet may in embodiments also be a stage lighting device and / or a search lighting device. Hence, according to a second aspect, the invention provides a lighting device selected from the group of a lamp, a luminaire, a lighting fixture, a projector device, and an2024PF80342

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[0197] automotive lighting device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system.

[0198] The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light. The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.

[0199] BRIEF DESCRIPTION OF THE DRAWINGS

[0200] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0201] Figs. 1 schematically depicts an embodiment of the light generating system; Figs. 2 schematically depicts an embodiment of the light generating system comprising the second solid state light source;

[0202] Fig. 3 schematically depicts a top view of an embodiment of the light generating system; and

[0203] Fig. 4 schematically depicts an embodiment of the lighting device. The schematic drawings are not necessarily to scale.

[0204] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0205] Fig. 1A schematically depicts an embodiment of the light generating system 1000. The light generating system 1000 may comprise a first solid state light source 10, a first luminescent converter 2100, a second luminescent converter 2200, and a first thermally conductive body 3100. The first luminescent converter 2100 and the second luminescent converter 2200 may be configured physically separated by a shortest (face-to-face) distance di, thereby defining an inter-converter cavity 1200. In embodiments, 0.3 mm < di < 3 mm may apply. Further, the first luminescent converter 2100 may comprise a first converter first major face 2110 and a first converter second major face 2120 opposite the first converter first major face 2110. The first luminescent converter 2100 may especially be configured in thermal contact with the first thermally conductive body 3100 via the first converter second major face 2120. The first solid state light source 10 may comprise one or more of a laser light source and a superluminescent diode. Further, the first solid state light source 10 may be2024PF80342

[0206] 51

[0207] configured to generate first light source light 11. Especially, the first light source light 11 may have a first peak wavelength (λp₁) selected from the range of 380-490 nm. The first solid state light source 10 may be configured to irradiate the first converter first major face 2110 via a first optical path 31 between the first solid state light source 10 and the first luminescent converter 2100. Especially, the first optical path 31 between the first solid state light source 10 and the first luminescent converter 2100 may intersect at least part of the inter-converter cavity 1200 and pass by (but not intersect) the second luminescent converter 2200. Further, the first luminescent converter 2100 may be configured in the reflective mode. The first luminescent converter 2100 may be configured to convert (at least) part of the first light source light 11 received by the first luminescent converter 2100 into first luminescent converter light 2101. Additionally or alternatively, the first luminescent converter 2100 may be configured to reflect at least part of the first light source light 11 received by the first luminescent converter 2100 as reflected first light source light 111 to the second luminescent converter 2200 via the inter-converter cavity 1200. Hence, the second luminescent converter 2200 may be configured downstream of the first luminescent converter 2100. Further, the second luminescent converter 2200 may be configured to convert at least part of the reflected first light source light 111 received by the second luminescent converter 2200 into second luminescent converter light 2201. Additionally or alternatively, the second luminescent converter 2200 may be configured to transmit at least part of the first luminescent converter light 2101 received by the second luminescent converter 2200 via the inter-converter cavity 1200. Hence, the second luminescent converter 2200 may especially be configured in the transmissive mode. The light generating system 1000 may be configured to generate system light 1001 comprising (a) first luminescent converter light 2101 transmitted by the second luminescent converter 2200 and (b) second luminescent converter light 2201 (generated by the second luminescent converter 2200). Optionally, the second luminescent converter 2200 may be configured to transmit at least part of the reflected first light source light 111 received by the second luminescent converter 2200. In such embodiments, the system light 1001 may further comprise at least part of this reflected first light source light 111. Especially, in such embodiments, the system light 1001 may be white light having a correlated color temperature selected from the range of 2000-9000 K and a color rendering index of at least 70.

[0208] The first luminescent converter 2100 and the second luminescent converter 2200 may be configured parallel. Further, the first luminescent converter 2100 and the second luminescent converter 2200 may be configured aligned in a direction perpendicular to the first converter first major face 2110 (see Fig. 2A). Alternatively, the second luminescent2024PF80342

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[0210] converter 2200 may extend beyond the first luminescent converter 2100 (in a direction perpendicular to the first converter first major face 2110) on at least one side of the first luminescent converter 2100 (see e.g. Fig. 1A). In embodiments, one or more of the first luminescent converter 2100 and the second luminescent converter 2200 may comprise a ceramic phosphor tile. Additionally or alternatively, one or more of the first luminescent converter 2100 and the second luminescent converter 2200 may comprise a crystalline phosphor tile. Hence, the first luminescent converter 2100 may comprise a first luminescent material 210. Similarly, the second luminescent converter 2200 may comprise a second luminescent material 220. The first luminescent material 210 and the second luminescent material 220 may be of the same type, though this need not be the case (see also above).

[0211] The first optical path 31 incident on the first luminescent converter 2100 (and intersecting at least part of the inter-converter cavity 1200) may be configured at a (smallest) first angle (on) with the first converter first major face 2110. In embodiments, 20° ≤ α₁ ≤ 70° may apply. Further, the inter-converter cavity 1200 may comprise a gas other than air (such as especially a gas comprising one or more of a thermally conductive gas and an inert gas).

[0212] The second luminescent converter 2200 may comprise: (i) a second converter first major face 2210 configured facing the first luminescent converter 2100; (ii) a second converter second major face 2220 configured opposite the second converter first major face 2210; and (iii) one or more second converter side faces 2230 configured bridging the second converter first major face 2210 and the second converter second major face 2220. Further, the light generating system 1000 may comprise a second thermally conductive body 3200. The second thermally conductive body 3200 may be configured in thermal contact with the second luminescent converter 2200 at one or more of: (a) at least part of the second converter first major face 2210; (b) at least part of the second converter second major face 2220; and (c) at least part of the one or more second converter side faces 2230.

[0213] The light generating system 1000 may comprise a surface-mounted device 500. The surface-mounted device 500 may especially comprise the first solid state light source 10, the first luminescent converter 2100, and the second luminescent converter 2200.

[0214] Fig. IB schematically depicts a further embodiment of the light generating system 1000. Here, (at least part of) the second thermally conductive body 3200 may especially be light transparent, wherein the second thermally conductive body 3200 may be configured in thermal contact with the second luminescent converter 2200 at one or more of the second converter first major face 2210 and the second converter second major face 2220. The second luminescent converter 2200 may have a second height H₂ (perpendicular to the2024PF80342

[0215] 53

[0216] second converter first major face 2210). Similarly, the first luminescent converter 2100 may have a first height H₁ (perpendicular to the first converter first major face 2110). Inembodiments, (H₂ ≤ H₁, especially) H₂ ≤ 0.9*H₁ may apply.

[0217] Fig. 1C schematically depicts a further embodiment of the light generating system 1000. The light generating system 1000 may comprise a light transparent body 400. The light transparent body 400 may especially be configured in the inter-converter cavity 1200. Further, the light transparent body 400 may be configured in physical contact with the first luminescent converter 2100 and the second luminescent converter 2200. The first optical path 31 may intersect the light transparent body 400. Further, at least part of the reflected first light source light 111 may be transmitted through the light transparent body 400 towards the second luminescent converter 2200. The light transparent body 400 may comprise one or more transparent body side faces 403. Especially, the one or more transparent body side faces 403 may be configured bridging the inter-converter cavity 1200 between the first luminescent converter 2100 and the second luminescent converter 2200. Further, at least one of the one or more transparent body side faces 403 may be configured at a smallest side angle (y) with the first converter first major face 2110. In embodiments, (80-α₁) < y < (100-α₁) may apply. Further, the light transparent body 400 may taper towards the second luminescent converter 2200. The light transparent body 400 may comprise a light transparent sapphire (crystal). Additionally or alternatively, the light transparent body 400 may be thermally conductive.

[0218] Fig. 2 schematically depicts a further embodiment of the light generating system 1000. The light generating system 1000 may comprise a second solid state light source 20. The second solid state light source 20 may especially comprise one or more of a laser light source and a superluminescent diode. Further, the second solid state light source 20 may be configured to generate second light source light 21. Especially, the second light source light 21 may have a second peak wavelength (λp₂) selected from the range of 380-490 nm. Further, as schematically depicted in Fig. 2A, the second solid state light source 20 may be configured to irradiate the first converter first major face 2110 via a second optical path 41 between the second solid state light source 20 and the first luminescent converter 2100. The second optical path 41 (between the second solid state light source 20 and the first luminescent converter 2100) may intersect at least part of the inter-converter cavity 1200 and pass by (but not intersect) the second luminescent converter 2200. In such embodiments, the first luminescent converter 2100 may be configured to convert (at least) part of the second light source light 21 received by the first luminescent converter 2100 into first luminescent converter light 2101. Further, in such embodiments, the first luminescent converter 2100 may2024PF80342

[0219] 54

[0220] be configured to reflect at least part of the second light source light 21 received by the first luminescent converter 2100 as reflected second light source light 121 to the second luminescent converter 2200 (via the inter-converter cavity 1200). The second luminescent converter 2200 may be configured to convert at least part of the reflected second light source light 121 received by the second luminescent converter 2200 into second luminescent converter light 2201. Alternatively, as schematically depicted in Fig. 2B, the second solid state light source 20 may be configured to irradiate the second converter second major face 2220 via a second optical path 41 between the second solid state light source 20 and the second luminescent converter 2200. In such embodiments, the second luminescent converter 2200 may be configured to (optionally) convert (at least) part of the second light source light 21 received by the second luminescent converter 2200 into second luminescent converter light 2201. Further, in such embodiments, the second luminescent converter may be configured to reflect at least part of the second light source light 21 received by the second luminescent converter 2200 as reflected second light source light 121. Hence, in embodiments, the system light 1001 may comprise at least part of the reflected second light source light 121.

[0221] The second optical path 41 (between the second solid state light source 20 and the first luminescent converter 2100 or between the second solid state light source 20 and the second luminescent converter 2200) may be configured at a (smallest) second angle (α₂) with one (or more) of the first converter first major face 2110 and the second converter secondmajor face 2220 (respectively). In embodiments, 20° ≤ α₂ ≤ 70° may apply. Further, as indicated above, the light generating system 1000 may comprise a surface-mounted device 500. The surface-mounted device 500 may optionally further comprise the second solid state light source 20. Further, the surface-mounted device 500 may optionally comprise one or more of: (i) the first thermally conductive body 3100, (ii) the light transparent body 400, and (iii) the second thermally conductive body 3200.

[0222] The light generating system 1000 may further comprise a lens 610. The lens 610 may be configured downstream of the first luminescent converter 2100 and the second luminescent converter 2200. Further, the lens 610 may be configured to collimate (a beam of) the system light 1001 received by the lens 610.

[0223] Fig. 3 schematically depicts a top view of the light generating system 1000, depicting a possible arrangement of the first solid state light source 10, the second solid state light source 20, the first luminescent converter 2100 (indicated by the dashed line), the second luminescent converter 2200, the first thermally conductive body 3100, and the second2024PF80342

[0224] 55

[0225] thermally conductive body 3200. In the embodiment depicted in Fig. 3, the second thermally conductive body 3200 may especially be configured in thermal contact with the second luminescent converter 2200 at (at least part of) the one or more second converter side faces 2230.

[0226] Fig. 4 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 of the light generating system 1000. Fig. 4 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device, which may also comprise the light generating system 1000. Reference 4 indicates an automotive lighting device, which may also comprise the light generating system 1000. Hence, Fig. 4 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1 (such as a torch), a luminaire 2, a lighting fixture (such as a stage lighting device and / or a search lighting device), a projector device 3, and an automotive lighting device 4, comprising the light generating system 1000 as described herein. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall.

[0227] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term “comprising” may in an embodiment refer to “consisting of’ but may in another embodiment also refer to “containing at least the defined species and optionally one or more other species”. Use of the verb “to comprise” and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed2024PF80342

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[0229] to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0230] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0231] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0232] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system. The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and / or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and / or shown in the attached drawings.

[0233] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

2024PF8034257CLAIMS:

1. A light generating system (1000) comprising a first solid state light source (10), a first luminescent converter (2100), a second luminescent converter (2200), and a first thermally conductive body (3100); wherein:the first luminescent converter (2100) and the second luminescent converter (2200) are configured physically separated by a shortest distance di, thereby defining an inter-converter cavity (1200); wherein 0.3 mm < di < 3 mm;the first luminescent converter (2100) comprises a first converter first major face (2110) and a first converter second major face (2120) opposite the first converter first major face (2110); wherein the first luminescent converter (2100) is configured in thermal contact with the first thermally conductive body (3100) via the first converter second major face (2120);the first solid state light source (10) comprises one or more of a laser light source and a superluminescent diode, wherein the first solid state light source (10) is configured to generate first light source light (11); wherein the first light source light (11) has a first peak wavelength (λp₁) selected from the range of 380-490 nm; wherein the first solid state light source (10) is configured to irradiate the first converter first major face (2110) via a first optical path (31) between the first solid state light source (10) and the first luminescent converter (2100); wherein the first optical path (31) between the first solid state light source (10) and the first luminescent converter (2100) intersects at least part of the inter-converter cavity (1200) and passes by the second luminescent converter (2200); wherein the first luminescent converter (2100) is configured in the reflective mode; wherein the first luminescent converter (2100) is configured to (i) convert part of the first light source light (11) received by the first luminescent converter (2100) into first luminescent converter light (2101), and (ii) reflect at least part of the first light source light (11) received by the first luminescent converter (2100) as reflected first light source light (111) to the second luminescent converter (2200) via the inter-converter cavity (1200);the second luminescent converter (2200) is configured downstream of the first luminescent converter (2100); wherein the second luminescent converter (2200) comprises: (i) a second converter first major face (2210) configured facing the first luminescent2024PF8034258converter (2100); (ii) a second converter second major face (2220) configured opposite the second converter first major face (2210); wherein the second luminescent converter (2200) is configured to (a) convert at least part of the reflected first light source light (111) received by the second luminescent converter (2200) into second luminescent converter light (2201), and (b) transmit at least part of the first luminescent converter light (2101) received by the second luminescent converter (2200) via the inter-converter cavity (1200); wherein the second luminescent converter (2200) is configured in the transmissive mode;the light generating system (1000) comprises a second solid state light source (20); wherein the second solid state light source (20) comprises one or more of a laser light source and a superluminescent diode; wherein the second solid state light source (20) is configured to generate second light source light (21); wherein the second light source light (21) has a second peak wavelength (λp₂) selected from the range of 380-490 nm; wherein one of the following applies:(a) the second solid state light source (20) is configured to irradiate the first converter first major face (2110) via a second optical path (41) between the second solid state light source (20) and the first luminescent converter (2100); wherein the second optical path (41) intersects at least part of the inter-converter cavity (1200) and passes by the second luminescent converter (2200); wherein the first luminescent converter (2100) is configured to (i) convert part of the second light source light (21) received by the first luminescent converter (2100) into first luminescent converter light (2101), and (ii) reflect at least part of the second light source light (21) received by the first luminescent converter (2100) as reflected second light source light (121) to the second luminescent converter (2200); wherein the second luminescent converter (2200) is configured to convert at least part of the reflected second light source light (121) received by the second luminescent converter (2200) into second luminescent converter light (2201); and(b) the second solid state light source (20) is configured to irradiate the second converter second major face (2220) via a second optical path (41) between the second solid state light source (20) and the second luminescent converter (2200); wherein the second luminescent converter (2200) is configured to (i) convert part of the second light source light (21) received by the second luminescent converter (2200) into second luminescent converter light (2201), and (ii) reflect at least part of the second light source light (21) received by the second luminescent converter (2200) as reflected second light source light (121); and2024PF8034259the light generating system (1000) is configured to generate system light (1001) comprising (a) first luminescent converter light (2101) transmitted by the second luminescent converter (2200) and (b) second luminescent converter light (2201).

2. The light generating system (1000) according to claim 1, wherein the first luminescent converter (2100) and the second luminescent converter (2200) are configured parallel.

3. The light generating system (1000) according to any one of the preceding claims, wherein the first optical path (31) incident on the first luminescent converter (2100) is configured at a first angle (α₁) with the first converter first major face (2110); wherein 20° ≤ α₁ ≤ 70°.

4. The light generating system (1000) according to any one of the preceding claims, wherein the inter-converter cavity (1200) comprises a gas other than air.

5. The light generating system (1000) according to any one of the preceding claims 1-3, wherein the light generating system (1000) comprises a light transparent body (400); wherein the light transparent body (400) is configured in the inter-converter cavity (1200); wherein the light transparent body (400) is configured in physical contact with the first luminescent converter (2100) and the second luminescent converter (2200); wherein the first optical path (31) intersects the light transparent body (400); and wherein at least part of the reflected first light source light (111) is transmitted through the light transparent body (400) towards the second luminescent converter (2200).

6. The light generating system (1000) according to claim 5, wherein the light transparent body (400) comprises one or more transparent body side faces (403), wherein the one or more transparent body side faces (403) are configured bridging the inter-converter cavity (1200) between the first luminescent converter (2100) and the second luminescent converter (2200); wherein at least one of the one or more transparent body side faces (403) is configured at a smallest side angle (y) with the first converter first major face (2110); wherein (80-α₁) < y < (100-α₁); wherein α₁ is as defined in claim 3; and wherein the light transparent body (400) tapers towards the second luminescent converter (2200).2024PF80342607. The light generating system (1000) according to any one of the preceding claims, wherein one or more applies of:one or more of the first luminescent converter (2100) and the second luminescent converter (2200) comprises a ceramic phosphor tile; andone or more of the first luminescent converter (2100) and the second luminescent converter (2200) comprises a crystalline phosphor tile.

8. The light generating system (1000) according to any one of the preceding claims, wherein:the second luminescent converter (2200) comprises one or more second converter side faces (2230) configured bridging the second converter first major face (2210) and the second converter second major face (2220); andthe light generating system (1000) comprises a second thermally conductive body (3200), wherein the second thermally conductive body (3200) is configured in thermal contact with the second luminescent converter (2200) at one or more of: (a) at least part of the second converter first major face (2210); (b) at least part of the second converter second major face (2220); and (c) at least part of the one or more second converter side faces (2230)9. The light generating system (1000) according to any one of the preceding claims, wherein the first light source light (11) has a first full width at half maximum (FWHM1); wherein the reflected first light source light (111) received at the second converter first major face (2210) as defined in claim 8 has a second full width at half maximum (FWHM2); wherein the reflected first light source light (111), transmitted by the second luminescent converter (2200) and escaping from the second converter second major face (2220) as defined in claim 8 has a third full width at half maximum (FWHM3) downstream of the second luminescent converter (2200); wherein FWHM3 > FWHM2 and FWHM2 > FWHM1.

10. The light generating system (1000) according to any one of the preceding claims, wherein:the first luminescent converter light (2101) has a first centroid wavelength (λc₁) selected from the range of 490-590 nm; andthe second luminescent converter light (2201) has a second centroid wavelength (λc₂) selected from the range of 590-690 nm.2024PF803426111. The light generating system (1000) according to any one of the preceding claims, wherein the second luminescent converter (2200) is configured to transmit at least part of the reflected first light source light (111) received by the second luminescent converter (2200); and wherein the system light (1001) further comprises at least part of this reflected first light source light (111).

12. The light generating system (1000) according to any one of the preceding claims, wherein the system light (1001) is white light having a correlated color temperature selected from the range of 2000-9000 K and a color rendering index of at least 70.

13. The light generating system (1000) according to any one of the preceding claims, wherein the second optical path (41) is configured at a second angle (ai) with one of the first converter first major face (2110) and the second converter second major face (2220); wherein 20° < 012 < 70°.

14. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a surface-mounted device (500); wherein the surface-mounted device (500) comprises the first solid state light source (10), the first luminescent converter (2100), and the second luminescent converter (2200), wherein the surface-mounted device (500) may optionally further comprise the second solid state light source (20) as defined in claim 12.

15. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), a lighting fixture, a projector device (3), and an automotive lighting device (4), comprising the light generating system (1000) according to any one of the preceding claims.

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