High-brightness laser-phosphor light source projecting polarized laser and polarized phosphor light onto a reflective diffuser

Abstract

The invention provides a light generating system (1000) comprising a first light generating device (110), a first luminescent material (210), a diffuser assembly (700), optical elements (500), and a light exit (1090), wherein; (A) the first light generating device (110) is configured to generate first device light (111); (B) the first luminescent material (210) is configured in the transmissive mode; wherein the first luminescent material (210) is configured (i) to convert at least part of the first device light (111) into first luminescent material light (211), and (ii) to transmit at least part of the first device light (111) to the diffuser assembly (700); (C) the optical elements (500) comprise a reflective polarizer (501) configured in an optical path between the first luminescent material (210) and the diffuser assembly (700); wherein the reflective polarizer (501) is configured (i) to reflect (ia) first device light (111) and (ib) first luminescent material light (211) having the first polarization back to the first luminescent material (210), and (ii) to transmit (iia) first device light (111) and (iib) first luminescent material light (211) having the second polarization to the diffuser assembly (700); wherein the first linear polarization and the second linear polarization are different linear polarizations; (D) the diffuser assembly (700) comprises a diffuser (710) configured in the reflective mode and a polarization converter (720); wherein the diffuser (710) is configured to diffuse the first device light (111) and the luminescent material light (201) into diffused first device light (711) and diffused luminescent material light (271); (E) the optical elements (500) further comprise a first polarization based redirection optical element (510) configured in an optical path between the reflective polarizer (501) and the diffuser assembly (700); wherein the first polarization based redirection optical element (510) is configured to (i) direct (ia) the luminescent material light (201) and (ib) first device light (111) having the second polarization to the diffuser assembly (700), and to (ii) direct (iia) diffused first device light (711) and (iib) diffused luminescent material light (271) having the first polarization to the light exit (1090); and (F) the light generating system (1000) is configured to generate system light (1001), wherein the system light (1001), in an operational mode of the light generating system (1000), comprises at least part of the diffused luminescent material light (271) and at least part of the diffused first device light (711).

Description

[0001] 2024PF80236

[0002] 1

[0003] High-brightness laser-phosphor light source projecting polarized laser and polarized phosphor light onto a reflective diffuser

[0004] FIELD OF THE INVENTION

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

[0006] BACKGROUND OF THE INVENTION

[0007] Laser-based light generating devices are known in the art. US2019323803A1, for instance, describes a laser system comprising: an active laser with at least one beam guide and an effective range about an object / target when the active laser is in use; a protection device with at least one additional laser that operates in a visible spectral range, wherein the at least one additional laser is switched on if at least one person has been detected in the effective range of the active laser before the active laser is used.

[0008] SUMMARY OF THE INVENTION

[0009] 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. However, such light engine may be capable to generate only a single color point as defined by the luminescent converter. Creation of a product range providing different color points may be difficult as it may require multiple unique components to be designed, qualified, produced, and kept in stock. In other cases, e.g., in RGB LCD-based projection systems, the maximum brightness may be limited by the components used, the engine volume may be large due to the many components, and the system cost may be high due to the many dedicated components. A way to combine pump light and luminescent light may be to use a polarizing beam splitter for the pump light, by which part of the light is reflected to the luminescent material and part is transmitted to a diffuser. However, in general the diffused light may to a large degree be depolarized, resulting in relatively high losses of diffused blue light at the beam combiner where it is combined with the luminescent light into white output light. In addition, using a 2024PF80236

[0010] 2 single laser source (that may comprise multiple laser diodes) may significantly limit the maximum output power due to size limitations to the optical components.

[0011] Hence, in may be desired to provide higher flux high brightness light engines that provide improved optical performance, while remaining compact and eye-safe architectures. 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.

[0012] According to a first aspect, the invention provides a light generating system comprising a first light generating device, a first luminescent material, a diffuser assembly, optical elements, and a light exit. In embodiments, the first light generating device may be configured to generate first device light. Especially, the first light generating device may comprise a first solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. In embodiments, the first luminescent material may be configured in a light-receiving relationship with the first light generating device. Especially, the first luminescent material may be configured in the transmissive mode. Further, in embodiments, the first luminescent material may be configured to convert at least part of the first device light received by the first luminescent material into first luminescent material light. Moreover, in embodiments, the first luminescent material may be configured to transmit at least part of the first device light received by the first luminescent material in an optical path to the diffuser assembly. Furthermore, in embodiments, the optical elements may comprise a reflective polarizer configured in an optical path between the first luminescent material and the diffuser assembly. Especially, in embodiments, the reflective polarizer may be configured to reflect light, received by the reflective polarizer, and having a first linear polarization, back to the first luminescent material. More especially, in embodiments, the reflective polarizer may be configured to reflect (first device light and) first luminescent material light, (both) having the first linear polarization (both having been) received by the reflective polarizer, back to the first luminescent material. Additionally, in embodiments, the reflective polarizer may be configured to transmit light, received by the reflective polarizer, and having a second linear polarization, in an optical path to the diffuser assembly. The first linear polarization and the second linear polarization may be different (especially complementary polarizations). In embodiments, the reflective polarizer may be configured to transmit first device light and first luminescent material light, (both) having the second linear polarization direction and 2024PF80236

[0013] 3

[0014] (both having been) received by the reflective polarizer, in an optical path to the diffuser assembly. Further, in embodiments, the diffuser assembly may comprise a diffuser and a polarization converter. In embodiments, the diffuser may comprise a polarization maintaining diffuser. Furthermore, in embodiments, the diffuser may be configured in the reflective mode. Especially, in embodiments, the diffuser may be configured to diffuse (and reflect) the first device light and the luminescent material light received by the diffuser into diffused first device light and diffused (first) luminescent material light (, respectively). Moreover, in embodiments, the polarization converter may be configured in an optical path between the reflective polarizer and the diffuser. Especially, the polarization converter may be configured to convert linear polarized light received by the polarization converter into elliptical polarized light. Additionally, the polarization converter may be configured to convert elliptical polarized light received by the polarization converter into linear polarized light. In embodiments, the optical elements may further comprise a first polarization-based redirection optical element. Especially, in embodiments, the first polarization-based redirection optical element may be configured in an optical path between the reflective polarizer and the (reflective) diffuser assembly. The first polarization based redirection optical element may, in embodiments, be configured to direct (i) luminescent material light, received by the first polarization based redirection optical element and having the second linear polarization, and (ii) (unconverted) first device light, received by the first polarization based redirection optical element and having the second linear polarization, in an optical path to the diffuser assembly. Additionally, in embodiments, the first polarization based redirection optical element may be configured to direct (i) diffused first device light, received by the first polarization based redirection optical element and having the first linear polarization, and (ii) diffused luminescent material light, received by the first polarization based redirection optical element and having the first linear polarization, in an optical path to the light exit. Therefore, in embodiments, the light generating system may be configured to generate system light. Further, in embodiments, the system light, in an operational mode of the light generating system, may comprise at least part of the diffused luminescent material light and at least part of the diffused first device light. Hence, in specific embodiments, the invention may provide a light generating system comprising a first light generating device, a first luminescent material, a diffuser assembly, optical elements, and a light exit, wherein; (A) the first light generating device is configured to generate first device light, wherein the first light generating device comprises a first solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting 2024PF80236

[0015] 4 diodes; (B) the first luminescent material is configured in a light-receiving relationship with the first light generating device; wherein the first luminescent material is configured in the transmissive mode; wherein the first luminescent material is configured to convert at least part of the first device light received by the first luminescent material into first luminescent material light; wherein the first luminescent material is configured to transmit at least part of the first device light received by the first luminescent material in an optical path to the diffuser assembly; (C) the optical elements comprise a reflective polarizer configured in an optical path between the first luminescent material and the diffuser assembly; wherein the reflective polarizer is configured (i) to reflect ( first device light received by the reflective polarizer and having a first linear polarization, and) first luminescent material light received by the reflective polarizer and having the first linear polarization back to the first luminescent material, and (ii) to transmit (iia) first device light received by the reflective polarizer and having a second linear polarization, and (iib) first luminescent material light received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly; wherein the first linear polarization and the second linear polarization are different; (D) the diffuser assembly comprises a diffuser and a polarization converter; wherein the diffuser comprises a polarization maintaining diffuser, wherein the diffuser is configured in the reflective mode; wherein the diffuser is configured to diffuse the first device light and the luminescent material light received by the diffuser into diffused first device light and diffused luminescent material light; wherein the polarization converter is configured in an optical path between the reflective polarizer and the diffuser; wherein the polarization converter is configured (a) to convert linear polarized light received by the polarization converter into elliptical polarized light and (b) to convert elliptical polarized light received by the polarization converter into linear polarized light; (E) the optical elements further comprise a first polarization based redirection optical element; wherein the first polarization based redirection optical element is configured in an optical path between the reflective polarizer and the diffuser assembly; wherein the first polarization based redirection optical element is configured to (i) direct (ia) the luminescent material light received by the first polarization based redirection optical element and having the second linear polarization and (ib) first device light received by the first polarization based redirection optical element and having the second linear polarization in an optical path to the diffuser assembly, and to (ii) direct (iia) diffused first device light received by the first polarization based redirection optical element and having the first linear polarization and (iib) diffused luminescent material light received by the first polarization based redirection optical element and having the first linear 2024PF80236

[0016] 5 polarization in an optical path to the light exit; and (F) the light generating system may be configured to generate system light, wherein the system light, in an operational mode of the light generating system, comprises at least part of the diffused luminescent material light and at least part of the diffused first device light.

[0017] With such a light generating system, instead of using a luminescent material in the reflective mode, the luminescent material is used to convert (at least part of) and / or transmit (at least part of) the (laser) device light towards the diffuser assembly. The resultant luminescent material light and / or (blue) laser light may both be provided to and diffused by the downstream diffuser assembly. With such a light generating system high-brightness system light may be provided having a wide range of potential spectral power distributions, e.g., blue light and / or yellow / green light. Moreover, with such a light generating system white system light may be provided with relatively high brightness, color rendering, and radiance (or luminance), i.e., a high optical power (density) of the source. Additionally, the system light may have improved homogeneity of the blue light and (yellow) converted light. Furthermore, with such system, a high-power light generating system may be provided. Yet, such system may in a safe way provide high power light. The system may be relatively compact. Yet, thermal management of the luminescent material may also be provided with this system. Hence, such a system as described here may provide a high-brightness laser- phosphor light source projecting polarized laser and polarized phosphor light onto a reflective diffuser.

[0018] The light generating system (or “system”) may thus comprise a first light generating device, a first luminescent material, a diffuser assembly, optical elements, and a light exit. Especially, in embodiments, the light generating system may comprise a first arrangement comprising the first light generating device, the first luminescent material, the diffuser assembly, and optical elements. Here below, embodiments of the different components of the light generating system will be described in further detail.

[0019] The light generating system may thus comprise a first arrangement. In embodiments, the first arrangement may comprise a first light generating device, a first luminescent material, a (first) diffuser assembly, and optical elements. The optical elements may, in embodiments, be configured to (re-)direct (or guide) first device light (generated by the first light generating device) to the first luminescent material. Additionally, in embodiments, the optical elements may be configured to (re-)direct (or guide) first device light and / or first luminescent material light (provided by the first luminescent material) to the (first) diffuser assembly. Yet additionally, in embodiments, the optical elements may be 2024PF80236

[0020] 6 configured to (re-)direct (or guide) diffused first device light and / or diffused luminescent material light (provided by the (first) diffuser assembly) to the light exit. Therefore, in embodiments, the first arrangement (especially the optical elements) may comprise at least a first (polarization-based) redirection optical element. Furthermore, in embodiments, the first arrangement (especially the optical elements) may comprise a (first) reflective polarizer.

[0021] In embodiments, the first arrangement may thus be a first lighting arrangement. The light generating system may, in embodiments, comprise further lighting arrangements, see also below. Hence, in embodiments, the light generating system may comprise light generating devices. Herein, light generating devices may be configured to generate device light. Therefore, in embodiments, the light generating devices may each comprise a solid-state light source. In embodiments, the light generating devices may comprise at least the first light generating device. The first light generating device may, in embodiments, be configured to generate first device light. Therefore, in embodiments, the first light generating device may comprise a first light source. The first light source may be essentially any light source, see also further below. Especially, in embodiments, the (first light source of the) first light generating device may comprise a first solid state light source. Hence, in embodiments, the first light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The first light generating device may herein also comprise a plurality of first (solid state) light sources. Especially, in specific embodiments, the first light generating device may comprise a first laser bank. In such embodiments, the first laser bank may comprise a first array comprising a plurality of first solid state light sources. Especially, in embodiments, the first laser bank may comprise a first array comprising a plurality of first lasers. For example, in embodiments, the first array may comprise an n*m array. In such embodiments, n and m may be individually selected from the range of 1-28, such as from the range of 2-20, like from the range of 4-14. However, in embodiments, other array types, such as e.g. an irregular array comprising a different number of lasers per row, may also be applied. Hence, in embodiments, each of the light generating devices may comprise a laser bank comprising a plurality of diode lasers A laser bank may comprise a relatively dense assembly of multiple laser diodes on a shared substrate provided with collimating optics, such as collimating lenses comprising one lens per laser diode (e.g., arranged in an array of lenses, see also further below). The use of laser banks may especially be convenient for projecting a beam of high- power laser light onto a luminescent converter without the need for using an inverse beam 2024PF80236

[0022] 7 expander. Depending on the desired output beam characteristics, additional beam shaping optics may be needed.

[0023] Note that an array of solid-state light sources may provide multiple light generating devices, such as a first light generating device and a second light generating device. For instance, a subset of laser diodes of an array of laser diodes may be used as first light generating device, and its device light may at least partially follow another optical path than device light of another subset of laser diodes from that array (of laser diodes). Hence, in embodiments a single laser bank may be applied, of which the light is split in multiple portions, effectively providing multiple light generating devices. In general, this may imply the application of optics, allowing to divide the laser light of multiple subsets of lasers from the same bank into their respective (separate) beams of light that at least partially do not have identical optical paths (in the light generating system). The subsets may comprise one or more of the laser diodes of the laser bank. However, especially a single laser diode may only be comprised by a single subset. Notwithstanding such embodiments, of course also multiple laser banks may be used to provide multiple light generating devices.

[0024] Further, in embodiments, the first light generating device may especially be configured to generate first device light having a first centroid wavelength (Xci). The term “centroid wavelength”, also indicated as c, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula kc = X I(k) / (S I( A)), where the summation is over the wavelength range of interest, and I(k) 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. Especially, in embodiments, (at least part of) the first device light may have a first centroid wavelength (Xci) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. More especially, in embodiments, (at least part of) the first device light may have a first centroid wavelength (Xci) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, in an operational mode of the light generating system, the first device light may be blue light. The terms “blue light” or “blue emission”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues). However, intensity at shorter wavelengths may also be possible, such as within the wavelength range of 400-440 2024PF80236

[0025] 8 nm. Especially, in embodiments the device light has a centroid wavelength selected from the blue wavelength range.

[0026] In embodiments, the first light generating device may be configured to provide first device light in an optical path to the first luminescent material. Hence, in embodiments, the first luminescent material may be configured downstream of (especially in a lightreceiving relationship with) the first light generating device. The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the 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”.

[0027] The first luminescent material may thus be configured in a light-receiving relationship with the first light generating device. In embodiments, the first luminescent material may be configured to convert at least part of the first device light (and optionally further device light, see also further below) received by the first luminescent material into first luminescent material light. The phrase “ ... light received by ...”, and similar phrases, such as “device light received by the first redirection optical element” may especially indicate that when the light is actually received by an item, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. Further, the action may also include refraction. Whether or not such item receives light may e.g. depend on a controlling mode (for instance whether or not a light generating device provides light).

[0028] In embodiments, the first luminescent material may be configured to convert at least part of the first device light received by the first luminescent material into first luminescent material light. Especially, in embodiments, the first luminescent material may be configured to convert at least 50%, like at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the first device light received by the first luminescent material into first luminescent material light. In specific embodiments, the first luminescent material may be configured to convert at least 95%, like at least 98%, such as at least 99%, including essentially 100% of the first device light received by the first luminescent material into first luminescent material light. Hence, in such embodiments, the first luminescent material may be configured in a full conversion mode. In such embodiments, the light generating system may be configured to generate system light essentially consisting of (diffused) first luminescent material light. Hence, in an alternative aspect, the invention may 2024PF80236

[0029] 9 provide a light generating system comprising a first light generating device, a first luminescent material, a diffuser assembly, optical elements, and a light exit, wherein; (A) the first light generating device is configured to generate first device light, wherein the first light generating device comprises a first solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (B) the first luminescent material is configured in a light-receiving relationship with the first light generating device; wherein the first luminescent material is configured in the transmissive mode; wherein the first luminescent material is configured to convert (essentially all of) the first device light received by the first luminescent material into first luminescent material light; (C) the optical elements comprise a reflective polarizer configured in an optical path between the first luminescent material and the diffuser assembly; wherein the reflective polarizer is configured (i) to reflect first luminescent material light received by the reflective polarizer and having the first linear polarization back to the first luminescent material, and (ii) to transmit first luminescent material light received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly; wherein the first linear polarization and the second linear polarization are different; (D) the diffuser assembly comprises a diffuser and a polarization converter; wherein the diffuser comprises a polarization maintaining diffuser, wherein the diffuser is configured in the reflective mode; wherein the diffuser is configured to diffuse the luminescent material light received by the diffuser into diffused luminescent material light; wherein the polarization converter is configured in an optical path between the reflective polarizer and the diffuser; wherein the polarization converter is configured (a) to convert linear polarized light received by the polarization converter into elliptical polarized light and (b) to convert elliptical polarized light received by the polarization converter into linear polarized light; (E) the optical elements further comprise a first polarization based redirection optical element; wherein the first polarization based redirection optical element is configured in an optical path between the reflective polarizer and the diffuser assembly; wherein the first polarization based redirection optical element is configured to (i) direct the luminescent material light received by the first polarization based redirection optical element and having the second linear polarization in an optical path to the diffuser assembly, and to (ii) direct diffused luminescent material light received by the first polarization based redirection optical element and having the first linear polarization in an optical path to the light exit; and (F) the light generating system is configured to generate system light, wherein the system light, in an 2024PF80236

[0030] 10 operational mode of the light generating system, comprises at least part of the diffused luminescent material light.

[0031] However, referring back to the first aspect of the invention, in embodiments, the light generating system may be configured to generate system light comprising the (diffused) first luminescent material light and further types of light (e.g. such as diffused first device light). Hence, in embodiments, the first luminescent material may be configured to convert at most 100%, such as at most 98%, especially at most 95%, more especially at most 90% of the first device light received by the first luminescent material into first luminescent material light. Note that the herein indicated percentages for luminescent conversion may refer to a quantum efficiency, i.e., a conversion efficiency from incident photons to luminescent photons. Alternatively, the efficiency of the luminescent material may be indicated with its energy conversion efficiency. Due to heat dissipation (i.e. thermal losses) caused by Stokes losses the energy conversion efficiency of the luminescent material may be configured to convert at most 90% (energy conversion efficiency), such as at most 88%, especially at most 85% of the (first) device light received by the luminescent material into luminescent material light.

[0032] Moreover, in embodiments, the first luminescent material may be configured to (scatter and) transmit at least part of the first device light received by the first luminescent material in an optical path to the diffuser assembly. Hence, in such embodiments, at least part of the first device light received by the first luminescent material may be transmitted as unconverted first device light, such that (unconverted) first device light may propagate in an optical path to the diffuser assembly. Especially, in embodiments, the first luminescent material may be configured to (scatter and) transmit at least 2%, like at least 3%, such as at least 5%, especially at least 10%, more especially at least 20% of the first device light received by the first luminescent material (as unconverted first device light) in an optical path (via the reflective polarizer) to the diffuser assembly. Further, in embodiments, the first luminescent material may be configured to convert at most 50%, such as at most 40%, especially at most 30%, more especially at most 25% of the first device light received by the first luminescent material (as unconverted first device light) in an optical path to the diffuser assembly. In specific embodiments, the first luminescent material may be configured to (i) convert at least 60% of the first device light received by the first luminescent material into first luminescent material light, and (ii) (scatter and) transmit at least 5% of the first device light received by the first luminescent material (as unconverted first device light) in an optical path to the reflective polarizer. Such embodiments may be beneficial as both (e.g. 2024PF80236

[0033] 11 blue) device light and (e.g. yellow / green) luminescent material light may be provided to the diffuser assembly. As the diffuser assembly may be configured to diffuse the light received by the diffuser assembly and provide said diffused light to the light exit (see also further below), the light generating system may thus be configured to generate system light having an improved spectral power distribution. In such embodiments, if the first centroid wavelength (Xci) is selected from blue wavelength range, the system light may even be white light, see also further below.

[0034] The term “luminescent material” especially refers to a material that can convert first radiati on, (especially one or more of UV radiation and blue radiation,) into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. Further, instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in the so-called downconversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in the so-called up-conversion.

[0035] In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation of a smaller wavelength is converted into radiation with a larger wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation of a larger wavelength is converted into radiation with a smaller wavelength ( x> m).

[0036] The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. When different luminescent materials are applied, one or more luminescent materials may be configured to convert incident light into one or more of green and yellow luminescent material light, and one or more other luminescent materials may be configured to convert incident light into one or more of orange and red luminescent material light. Hence, the term 2024PF80236

[0037] 12

[0038] “luminescent material” may in specific embodiments also refer to a luminescent material composition. The term “luminescent material” herein may also refer to a material comprising a luminescent material, such as a light transmissive host comprising the luminescent material.

[0039] In embodiments, luminescent materials are 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.

[0040] Especially, the luminescent material is configured to convert at least part of the light source light into luminescent material light, wherein the luminescent material may comprise a (garnet) luminescent material of the type AsBsOn 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. Hence, the luminescent material light may e.g. be green light or yellow light (or in specific embodiments even orange (dependent upon the composition of the garnet and cerium concentration)). However, other embodiments are also possible, see below. In embodiments, 0.05-10% of the A elements comprise Ce, even more especially 0.05-5%, such as 0.1-5%. Especially, embodiments, 0.1-3% of the A elements comprise Ce, such as up to 2%, like selected from the range of 0.1-1.5%, such as at least above 0.5%.

[0041] The luminescent material may comprise an organic group that converts the light, or a molecule that converts the light, or an inorganic group that converts the light, etc. Such groups (or molecule) may be indicated as converter element. The garnet type material as indicated above, comprises cerium (Ce) as converter element. Cerium comprising garnets are well known in the art.

[0042] Hence, in embodiments, the luminescent material comprises a luminescent material of the type AsBsOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. In specific embodiments the first luminescent material comprises at least a luminescent material of the type AsBsO Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. 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 2024PF80236

[0043] 13 especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less 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 (Yi-xLux)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 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. For instance, in the case of (Yi-xLux)3AhOi2:Ce, part of Y and / or Lu 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). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.sgCeo.o sALOn. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0044] In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+and / or NfcSis Eu2and / or MAlSiHrEu2and / or Ca2AlSi3O2Ns: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)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. 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 is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba.

[0045] In embodiments, the luminescent material may comprise a luminescent material of the type M’xM2-2XAXe doped with tetravalent manganese, wherein M’ comprises 2024PF80236

[0046] 14 an alkaline earth cation, M comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, for instance comprising one or more of silicon and titanium, wherein X comprises a monovalent anion, at least comprising fluorine. 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. Herein, M’xM2-2xAX6 doped with tetravalent manganese, may further also shortly be indicated as “phosphor”, i.e. the phrase " phosphor comprising M’xM2-2xAX6 doped with tetravalent manganese" may in an embodiment also be read as M’xM2-2xAX6 doped with tetraval ent manganese phosphor, or (tetraval ent) Mn-doped M’XM2-2XAX6 phosphor, or shortly "phosphor".

[0047] Relevant alkaline cations (M) are sodium (Na), potassium (K) and rubidium (Rb). Optionally, also lithium and / or cesium may be applied. 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’xM2-2xAX6 , 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- 2xAXe luminescent material has the cubic phase. Relevant alkaline earth cations (M’) are magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. In an embodiment, a combination of different alkaline cations may be applied. In yet another embodiment, a combination of different alkaline earth cations may be applied. In yet another embodiment, a combination of one or more alkaline cations and one or more alkaline earth cations may be applied. For instance, KRbo.sSro^sAXe might be applied. As indicated above, x may be in the range of 0-1, especially x<l. In an embodiment, x=0.

[0048] The term “tetravalent manganese” refers to Mn4+. This is a well-known luminescent ion. In the formula as indicated above, part of the tetravalent 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. The mole percentage of manganese, i.e. the percentage it replaces the tetravalent 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.

[0049] In an embodiment, M’xM2-2xAX6 comprises K^SiFe (indicated herein also as KSiF system). As indicated above, in another preferred embodiment, M’xM2-2xAX6 comprises KRbSiFe (herein also indicated as K,Rb system). As indicated above, part of 2024PF80236

[0050] 15 silicon is replaced by manganese (i.e. the formula may also be described as K2Sii-mMnmF6 or KRbSii-mMnmF6, with m as indicated above, or as KRbSiFe:Mn and K2SiFe:Mn, respectively). 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+). In specific embodiments, the luminescent material may comprise (K,Rb)2SiFe:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2SiFe:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2TiFe:Mn4+. In embodiments, the third luminescent material may comprise K2(Si,Ti)Fe:Mn4+. As can be derived from the above, “ Si,Ti” may indicate one or more of Si and Ti.

[0051] Especially, the luminescent material may be an inorganic luminescent material, such as one or more of the above-described trivalent cerium or divalent europium comprising oxides, oxynitrides, or nitrides.

[0052] Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.

[0053] The term “luminescent material” herein especially relates to inorganic luminescent materials.

[0054] Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots (and / or other quantum confinement structures) and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc. The term “quantum confinement structures” should, in the context of the present application, be understood as e.g. quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nano-wires, etcetera. Moreover, in embodiments, the first luminescent material may comprise multiple one or more different luminescent materials.

[0055] The first luminescent material may thus, in embodiments, be configured to convert first device light received by the first luminescent material into first luminescent material light. In specific embodiments, the first luminescent material light may have a first luminescent material centroid wavelength (XCLMI). Especially, in embodiments, the first luminescent material centroid wavelength (XCLMI) may be selected from the range of 490-620 nm, such as from the range of 500-600 nm, like from the range of 520-590 nm, especially from the range of 535-580 nm. Hence, in embodiments, the first luminescent material light may comprise, such as be, one or more of yellow light and green light, such as especially yellow light. The terms “green light” or “green emission” especially relate to light having a 2024PF80236

[0056] 16 wavelength in the range of about 495-570 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 570-590 nm. Alternatively, in embodiments, the first luminescent material centroid wavelength (XCLMI) may be selected from the range of 600-660 nm, like from the range of 610-650 nm, such as from the range of 620-640 nm. Hence, in embodiments, the first luminescent material 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.

[0057] Further, in embodiments, the first luminescent material centroid wavelength (XCLMI) may be different from the first centroid wavelength (Xci). Especially, in embodiments, |XCI-XCLMI|>5 nm, such as |XCI-XCLMI|>10 nm, like |XCI-XCLMI|>15 nm, especially, |XCI-XCLMI|>20 nm. Moreover, in embodiments, |XCI-XCLMI|<150 nm, like |Xci- XCLMI|>100 nm. Such embodiments may be beneficial as the combination of the first device light and the first luminescent material light may (if their centroid wavelengths significantly differ) provide an improved spectral power distribution and color rendering of the system light.

[0058] In embodiments, the first luminescent material may be configured in the transmissive mode. In the transmissive mode, it may be relatively easy to have light source light admixed in the luminescent material light, which may be useful for generating the desirable spectral power distribution. Furthermore, the transmissive mode of the luminescent material may provide the benefit that the first device light and the first luminescent material light may be provided to the diffuser assembly, which may further diffuse the light to provide an eye-safe architecture for providing high-brightness (white) system light. Further, in such embodiments, the luminescent material may be applied in thermal contact with a thermally conductive element. An element may be considered in “thermal contact” with another element if it can exchange energy through the process of heat. In embodiments, thermal contact can be achieved by physical contact. In embodiments, thermal contact may be achieved via a thermally conductive material, such as a thermally conductive glue (or thermally conductive adhesive). Thermal contact may also be achieved between two elements when the two elements are arranged relative to each other at a distance of equal to or less than about 10 pm, though larger distances, such as up to 100 pm may be possible. The shorter the distance, the better the thermal contact. The distance may be the distanced 2024PF80236

[0059] 17 between two respective surfaces of the respective elements. The distance may be an average distance. When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum. When an intermediate material is available, the larger the distance, the higher the thermal conductivity may be useful for thermal contact between the two elements. However, the smaller the distance, the lower the thermal conductivity of the intermediate material may be (of course, higher thermal conductive materials may also be used).

[0060] Hence, in embodiments the luminescent material may be configured in thermal contact with a thermally conductive material. For instance, the luminescent material may be configured in thermal contact with a thermally conductive element.

[0061] A thermally conductive element may especially comprise thermally conductive material. A thermally conductive material may especially have a thermal conductivity of at least about 20 W / (m*K), like at least about 30 W / (m*K), such as at least about 100 W / (m*K), like especially at least about 200 W / (m*K). In yet further specific embodiments, a thermally conductive material may especially have a thermal conductivity of at least about 10 W / (m*K). 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, and graphite. Alternatively, or additionally, the thermally conductive material may comprise or consist of aluminum oxide. In embodiments, the thermally conductive element may comprise one or more of a heatsink, a heat spreader, and a two-phase cooling device. In yet other embodiments, the thermally conductive element may be configured in thermal contact with one or more of a heatsink, a heat spreader, and a two-phase cooling device, and may e.g. transfer heat to such heatsink, heat spreader, or two-phase cooling device, via another thermally conductive element.

[0062] In embodiments, the thermally conductive material may preferably be applied onto a rotating wheel, enabling superior thermal spreading and cooling without the need for e.g. active water cooling, and thereby enabling maximum possible irradiance values.

[0063] As mentioned above, the light generating system may comprise further optical elements. In embodiments, the optical elements may at least comprise a reflective polarizer. The reflective polarizer may, in embodiments, be configured in an optical path between the first luminescent material and the (first) diffuser assembly. As such, the reflective polarizer 2024PF80236

[0064] 18 may be configured in a light-receiving relationship with the first luminescent material. Especially, in embodiments, the reflective polarizer may be configured to receive the first device light and the first luminescent material light propagating from the first luminescent material. In embodiments, the reflective polarizer may be transmissive for a (main) linear polarization of the (first device and / or luminescent material) light propagating in the direction of the diffuser assembly, while being light reflective for a (minor) linear polarization of the (first device and / or luminescent material) light. Especially, in embodiments, the reflective polarizer may be configured to reflect light (received by the reflective polarizer and) having a first linear polarization and to transmit light (received by the reflective polarizer and) having a second linear polarization.

[0065] Hence, in embodiments, the first device light reaching the reflective polarizer (via the first luminescent material) may comprise polarized light. Similarly, in embodiments, in embodiments, the first luminescent material light reaching the reflective polarizer may comprise polarized light. Yet, the light generating system may be configured such that the first device light and the first luminescent material light reaching the reflective polarizer (via the first luminescent material) may comprise linear polarized light. Hence, the first device light may comprise linear polarized light and / or a polarizer may be configured downstream of the first light generating device and upstream of the first luminescent material such that the first device light and the first luminescent material light reaching the reflective polarizer may comprise linear polarized light. The term “linear polarized light” (or “linearly polarized light”) may herein refer to light having (electric field) oscillations predominantly aligned in a single plane. Hence, it is not excluded that some oscillations occur outside of the single plane, such as in a plane perpendicular thereto. For instance, in embodiments, the linear polarized light may have at least 80% of (electric field) oscillations in a single plane, such as at least 90%, especially at least 95%, such as at least 99%, including 100%. The linearly polarized light may, in embodiments, also comprise elliptically polarized light with a large ratio of perpendicular polarization components, such as a ratio > 4, especially > 6, such as > 10, especially > 20. As known in the art, linear polarized light may be generated by optical elements of solid state lasers, e.g., polarizing filters, laser cavity dimensional and / or structural characteristics, and / or intracavity elements. The linear polarizations s-polarized and p-polarized may be considered complementary polarizations (, perpendicular polarizations, or orthogonal polarizations).

[0066] In embodiments, the reflective polarizer may be configured to reflect light having a first linear polarization back to the first luminescent material. Conversely, in 2024PF80236

[0067] 19 embodiments, the reflective polarizer may be configured to transmit (only) light having a second linear polarization in an optical path to the diffuser assembly. In embodiments, the first linear polarization and the second linear polarization may be different (especially perpendicular or complementary polarizations). Especially, in embodiments, the first linear polarization may comprise one of p-polarization and s-polarization and the second linear polarization may comprise the other one of p-polarization and s-polarization. In specific embodiments, the first linear polarization may be s-polarization and the second linear polarization may be s-polarization.

[0068] The reflective polarizer may then, in embodiments, be configured to reflect first device light received by the reflective polarizer and having the first linear polarization back to the first luminescent material. Similarly, in embodiments, the reflective polarizer may be configured to reflect first luminescent material light received by the reflective polarizer and having the first linear polarization back to the first luminescent material. At the first luminescent material, this light having the first linear polarization may then be re-converted and re-emitted in an optical path to the reflective polarizer.

[0069] Further, in embodiments, the reflective polarizer may be configured to transmit first device light received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly. Similarly, in embodiments, the reflective polarizer may be configured to reflect first luminescent material light received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly.

[0070] In embodiments, the (first) diffuser assembly may thus be configured to receive at least part of the first device light (via the first luminescent material and (some of) the optical elements). Furthermore, in embodiments, the (first) diffuser assembly may also be configured to receive at least part of the first luminescent material light (via the first luminescent material and (some of) the optical elements). In embodiments, the diffuser assembly may comprise (at least) a (first) diffuser. The diffuser may, in embodiments, be configured to diffuse (or scatter) at least part of the (first device and / or first luminescent material) light received by the diffuser. Especially, in embodiments, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the first device light received by the diffuser into diffused first device light. Similarly, in embodiments, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the first luminescent material light received by the diffuser into diffused luminescent material light. 2024PF80236

[0071] 20

[0072] Similarly to the luminescent material, in embodiments, the diffuser assembly may be configured in the transmissive mode or in the reflective mode. Especially, in embodiments, the diffuser assembly (and thus the diffuser) may be configured in the reflective mode. Therefore, in embodiments, the diffuser may be (diffuse) reflective for (first device and / or first luminescent material) light. In embodiments, the diffuser may comprise a surface diffuser, a volume diffuser, or a combination of a surface and volume diffuser. The diffuser may, in embodiments, comprise one or more materials selected from the group comprising: a glass with high transmission in the spectral range of the first device light and / or the first luminescent material light , a silicone-based material, and a transparent ceramic material such as e.g. sapphire. Especially, in embodiments, the diffuser may comprise one (or more) of: a small angle scattering metallic substrate, a white ceramic reflector, a patterned glass-based substrate with a (deposited metallic or (layered) dielectric) reflective coating, a combination of optical micro-structures with specular reflective elements, a combination of a solid optical body with a diffuse reflector, a combination of a structured surface with a dichroic or thin film deposited reflector, and a combination of a total internal reflector element with additional surface structuring. The diffuser may especially be selected based on preferred system characteristics, such as thermal management, bulkiness, and cost. Moreover, in embodiments, the diffuser may comprise a polarization maintaining diffuser.

[0073] The diffuser may, in embodiments, thus be configured to diffuse (or scatter) the first device light and the first luminescent material light received by the diffuser. Especially, in such embodiments, the diffuser may comprise a reflective diffuser. Alternatively, in embodiments, the diffuser may comprise a transmissive diffuser combined with a (specular) reflective optical component configured behind (relative to a plane of incidence of) the transmissive diffuser. For example, the transmissive diffuser may comprise optical micro-structures configured to provide (both) transmissive and reflective diffusion of light received by the diffuser. In such embodiments, the reflective optical component may be configured to reflect transmi ssively diffused light that may otherwise be lost. Therefore, the reflective optical component may e.g. comprise a (specular) mirror coating configured on the diffuser and / or a discrete specular mirror configured externally (and not in optical contact) of the diffuser. Hence, in such embodiments, the diffuser may comprise a combination of optical micro-structures with a specular reflective element(s).

[0074] Furthermore, in embodiments, the (first) diffuser assembly may comprise a (first) polarization converter. In embodiments, the polarization converter may comprise a 2024PF80236

[0075] 21 birefringent rotator, more especially a X / 4 waveplate (or quarter waveplate). As known from the art, a waveplate or retarder is an optical device that may alter the polarization state of a light wave travelling through it depending on the orientation of the waveplate relative to the propagation direction and the state of polarization of the light wave. A halfwave plate may shift the polarization direction of linear polarized light (especially from s to p or from p to s polarization). Conversely, a quarter-wave plate may convert linear polarized light into elliptically (such as especially circularly) polarized light (and vice versa). Especially, herein, in embodiments, the quarter waveplate may be configured to convert linear polarized light received by the quarter waveplate into elliptical (such as especially circularly) polarized light. Additionally or alternatively, in embodiments, the quarter waveplate may be configured to convert elliptical polarized light (such as especially circularly polarized light) received by the quarter waveplate into linear polarized light. The X / 4 waveplate may especially be configured in an optical path between (relative to the propagation of light through the system) the reflective polarizer and the diffuser. As such, the quarter waveplate may, in embodiments, be configured to convert light received by the quarter waveplate having a linear polarization into light having a (first) elliptical (such as especially circular) polarization. At the diffuser, in embodiments, the light having the (first) elliptical polarization may be diffused into diffused light having a second elliptical (such as especially circular) polarization. Therefore, in embodiments, the quarter waveplate may also be configured to convert diffused light received by the quarter waveplate (via the diffuser) and having the (second) elliptical polarization into diffused light having a linear polarization. For example, in embodiments, the quarter waveplate may be configured to convert p-polarized light into left-handed elliptically polarized light. Further, in such embodiments, the diffuser may be configured to diffuse the left-handed elliptically polarized light received by the diffuser into right-handed elliptically polarized diffused light. The quarter waveplate may then, in embodiments, be configured to convert the right-handed elliptically polarized diffused light received by the quarter waveplate (back) to linear polarized light, especially to s-polarized diffused light. However, in embodiments, different polarizations and conversions from the example described here may be possible too, such as e.g. starting from s-polarized light. Hence, in embodiments, the diffuser assembly may comprise an arrangement of a polarization converter and a diffuser.

[0076] Further, in embodiments, the diffuser may comprise a static diffuser. Alternatively, in embodiments, the diffuser may comprise a dynamic diffuser, such as e.g. a rotating wheel comprising a reflective diffuser track. 2024PF80236

[0077] 22

[0078] Furthermore, in embodiments, the diffuser assembly may comprise condensing and collecting (or collimating) optical elements. In embodiments, the condensing and collecting optical elements may be located in an optical path between the (reflective) diffuser and the first luminescent material (such as e.g. between the diffuser and the polarization converter). In such embodiments, the condensing and collecting (or collimating) optical elements may comprise one or more positive lenses. As it may be advantageous to create a virtual diffused device light source with dimensions that are comparable to the luminescent material light, it may be preferred to apply a set of two, or possibly three positive condenser lenses to enable a large effective numerical aperture just as used in a reflective mode luminescent material configuration. For transmission efficiency as well as survival of the lenses, the induced stresses due to absorption of light may need to be limited. For this, in embodiments, a very low absorption glass with e.g. an internal transmission of at least 99.7% through 10 mm material may be applied. Hence, in embodiments, suitable glass materials may be selected from the group comprising: N-BK7, N-BK7HT, H-K9L, or H-K9LGT. Especially, in embodiments, the condenser and / or collecting optical elements may comprise fused silica (FS).

[0079] In embodiments, the optical elements may thus comprise one or more condensing and collecting optical elements, such as, e.g.. lenses. Moreover, in embodiments, the optical elements may comprise redirection optical elements. Herein, a redirection optical element may especially refer to an optical element configured to receive and redirect one or more beams of light.

[0080] In particular, in embodiments, the optical elements (especially the redirection optical elements) may comprise a first redirection optical element. Herein, instead of the term “redirection optical element” also the term “beam splitter” or “beam combiner” may be applied.

[0081] The first redirection optical element may especially (in an operational mode of the light generating system) be configured downstream of the first light generating device. Especially, in embodiments, the first redirection optical element may be configured in an optical path between the reflective polarizer and the (reflective) diffuser assembly. Hence, in embodiments, the first light generating device may especially be configured to provide first device light to the first redirection optical element (via the first luminescent material and the reflective polarizer). In such embodiments, the first redirection optical element may thus (during operation) be configured in a light-receiving relationship with the first light generating device. Furthermore, in embodiments, the first luminescent material may 2024PF80236

[0082] 23 especially be configured to provide first luminescent material light (and first device light) to the first redirection optical element (via the reflective polarizer). In such embodiments, the first redirection optical element may thus (during operation) be configured in a lightreceiving relationship with the first luminescent material.

[0083] In embodiments, the first redirection optical element may comprise a polarization-based redirection optical element, i.e., may comprise a polarizing beam splitter (PBS1) or a reflective polarizer. Hence, in embodiments, the first redirection optical element may also be referred to as a first polarization-based redirection optical element. In embodiments via polarization multiplexing, device light from different sources (such as the first light generating device and the diffuser) may be separated provided that they differ in (linear) polarization. For instance, s-polarized light and p-polarized light may be separated, or elliptically polarized light comprising relatively more p-polarization than s-polarization, and elliptically polarized light comprising relatively more s-polarization than p-polarization may be (at least partially) separated with a polarization-based redirection optical element (which may also be indicated as polarizing beam combiner or polarizing beam splitter).

[0084] A polarizing beam splitter may be considered an example of a redirection optical element. Light propagating to the polarizing beam splitter, and comprising both linear polarizations, like elliptically polarized light, may be split in two orthogonally propagating beams of light with complementary linear polarizations. Hence, this provides the polarizing beam splitter its beam splitting function. In other words, the polarizing beam splitter may redirect light having one linear polarization differently from light having the other (perpendicular) linear polarization. However, the opposite may also be true, two beams of light with complementary linear polarizations orthogonally propagating to the polarizing beam splitter may be combined in a single beam comprising both complementary linear polarizations and propagating along an axis parallel to an axis of one of the two beams of light with complementary linear polarizations orthogonally propagating to the polarizing beam splitter.

[0085] Hence, for the polarizing beam splitter may apply that for a first polarization, the transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30 % points, than for a second polarization. Similarly, for a first polarization, the reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30 % points, than for a second polarization. Especially, in embodiments, the polarizing beam splitter may be configured to direct at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the first 2024PF80236

[0086] 24 polarization to a first direction and at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the second polarization to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45- 135°, such as about 90°. The percentage of the light may refer to a spectral power (e.g. in Watt). Especially, the first polarization and the second polarization may comprise linear polarizations such as selected from s polarization and p polarization. Optionally, the first polarization and the second polarization may be selected from different elliptically polarized light. In embodiments, the polarizing beam splitters herein may be selected from reflective polarizing beam splitters (reflective polarizers).

[0087] In embodiments, the first device light and / or the first luminescent material light reaching the first redirection optical element may comprise (at least) the second linear polarization (e.g. p-polarization). Conversely, in embodiments, the diffused first device light and / or the diffused luminescent material light reaching the first redirection optical element may comprise (at least) the first linear polarization (e.g. s-polarization), different from the second linear polarization. The device light may, in embodiments, comprise a certain polarization as an intrinsic characteristic to the light generating device. In other embodiments, the device light may comprise a certain polarization as a result of polarizing optical elements (such as the polarization control system, see also further below) imposing that polarization onto the device light. In specific embodiments, the light generating system may be configured such that at least 70%, such as at least 80%, like at least 90%, especially at least 95%, including essentially 100% of the first device light reaching the first luminescent material may have the second linear polarization. Moreover, in embodiments, the light generating system may be configured such that at least 70%, such as at least 80%, like at least 90%, especially at least 95%, including essentially 100% of the first device light and the first luminescent material light reaching the first redirection optical element may have the second linear polarization. Such embodiments may be beneficial as the high percentage of second linear polarization (especially p-polarization) may improve the efficiency of the light generating system.

[0088] In embodiments, the first redirection optical element may be configured to (redirect light received by the first redirection optical element. The first redirection optical element may especially do so in dependence of the polarization of the light received by the first redirection optical element.

[0089] In embodiments, the first redirection optical element may be configured to (redirect light received by the first redirection optical element and having the second linear 2024PF80236

[0090] 25 polarization into an optical path to the diffuser assembly. Especially, in embodiments, the first redirection optical element may be configured to (re-)direct (such as transmit or reflect) luminescent material light received by the first redirection optical element and having the second linear polarization into an optical path to the diffuser assembly. Moreover, in embodiments, the first redirection optical element may be configured to (re-)direct (such as transmit or reflect) (unconverted) first device light received by the first redirection optical element and having the second linear polarization into an optical path to the diffuser assembly.

[0091] Additionally, in embodiments, the first redirection optical element may be configured to (re-)direct the light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit. Especially, in embodiments, the first redirection optical element may be configured to (re-)direct (such as reflect or transmit) the diffused luminescent material light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit. Moreover, in embodiments, the first redirection optical element may be configured to (redirect (such as reflect or transmit) the diffused first device light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit.

[0092] In specific embodiments, the first polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) transmit first device light having the second linear polarization, (ii) transmit first luminescent material light having the second linear polarization, (iii) reflect the diffused first device light having the first linear polarization, and (iv) reflect the diffused luminescent material light having the first linear polarization. Alternatively, in specific embodiments, the first polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) reflect first device light having the second linear polarization, (ii) reflect first luminescent material light having the second linear polarization, (iii) transmit the diffused first device light having the first linear polarization, and (iv) transmit the diffused luminescent material light having the first linear polarization. Such embodiments may be beneficial as the first redirection optical element may thus efficiently separate the beams of undiffused light from the beams of diffused light.

[0093] In embodiments, the light generating system may be configured to generate system light. As described above, the first redirection optical element may be configured to direct the diffused first device light and( / or) the diffused luminescent material light in a same 2024PF80236

[0094] 26 optical path to the light exit. Therefore, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of the diffused luminescent material light and at least part of the diffused first device light. Therefore, in embodiments, in an operational mode of the light generating system the system light may be white light.

[0095] 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 1800 K and 20000 K, such as between 2000 and 20000 K, especially 2700- 20000 K, for general lighting especially in the range of about 2000-7000 K, such as in the range of 2700 K and 6500 K. For example, in embodiments, the system light may be white light having a correlated color temperature (CCT) between about 2700 K and 12000 K. In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 2700 K and 6500 K, in combination with a CRI of at least 75, such as at least 80. Additionally or alternatively, in embodiments, in an operational mode of the light generating system, the system light may be white light having a color rendering index of at least 75, such as at least 80, like at least 85, especially at least 90. To achieve white light having such CCT and CRI ranges, the addition of the red third device light as described in this invention may be especially beneficial because of inadequate red spectral contributions in high brightness luminescent material light. In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 2000-12000K, such as selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, like at least 8000 K. Yet further, in embodiments the correlated color temperature (CCT) may be selected from the range of 2000-12000K, such as selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 65, such as at least 70.

[0096] In embodiments, e.g. for backlighting purposes, or for other purposes, the correlated color temperature (CCT) may especially be in the range of about 7000 K and 20000 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL.

[0097] However, in alternative embodiments, in another operational mode of the light generating system the system light may comprise (such as essentially consist of) the diffused luminescent material light. Hence, in such embodiments, the system light may for example be yellow-green light (e.g. in the case of a luminescent material of the type AsBsOn Ce). Alternatively, in embodiments, the system light may be orange-red light (e.g. in the case of a 2024PF80236

[0098] 27 luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese). Such embodiments may especially apply when the first luminescent material may be configured to convert at least 9%, such as at least 98%, especially at least 99%, including essentially 100% (i.e. full conversion mode) of the first device light received by the first luminescent material into first luminescent material light.

[0099] As the first luminescent material may herein especially be configured in the transmissive mode, the luminescent material may suffer from efficiency losses due to converted light being emitted in undesired directions (such as e.g. back to the first light generating device). Therefore, it may be advantageous to include a dichroic filter in the light generating system to recycle the otherwise lost light. Hence, in embodiments, the (light generating system especially the) optical elements may comprise a dichroic filter. The dichroic filter may especially be configured in an optical path between the first light generating device and the first luminescent material. In embodiments, the dichroic filter may be configured to transmit the first device light received by the dichroic filter in an optical path to the first luminescent material. As such, the first device light may be provided to excite the luminescent material. Furthermore, in embodiments, the dichroic filter may be configured to reflect the first luminescent material light received by the dichroic filter in an optical path back to the first luminescent material (and thus away from the first light generating device). As such, the first luminescent material light may be recycled and used to again excite the luminescent material. Hence, in embodiments, the optical elements may further comprise a dichroic filter configured in an optical path between the first light generating device and the first luminescent material, wherein the dichroic filter may be configured to (i) transmit the first device light and (ii) reflect the first luminescent material light.

[0100] The light generating system may, as described above, comprise a first arrangement the first light generating device, the first luminescent material, the diffuser assembly, and optical elements.. Further, in embodiments, the light generating system may comprise a subarrangement (also referred to as second subarrangement) comprising a second light generating device, a second polarization based redirection optical element, and a second diffuser assembly (and optical elements, such as e.g. lenses).

[0101] In embodiments, the light generating devices may thus comprise the second light generating device. The second light generating device may, in embodiments, be configured to generate second device light. Therefore, in embodiments, the second light generating device may comprise a second light source. The second light source may be essentially any light source, see also further below. Especially, in embodiments, the (second 2024PF80236

[0102] 28 light source of the) second light generating device may comprise a second solid state light source. Hence, in embodiments, the second light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The second light generating device may herein also comprise a plurality of second (solid state) light sources. Especially, in specific embodiments, the second light generating device may comprise a second laser bank. In such embodiments, the second laser bank may comprise a second array comprising a plurality of second solid state light sources. Especially, in embodiments, the second laser bank may comprise a second array comprising a plurality of second lasers (similarly to the first laser bank described above).

[0103] Further, in embodiments, the second light generating device may especially be configured to generate second device light having a second centroid wavelength (Xc2). Especially, in embodiments, (at least part of) the second device light may have a second centroid wavelength (Ac?) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. More especially, in embodiments, (at least part of) the second device light may have a second centroid wavelength (Xc2) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, in an operational mode of the light generating system, the second device light may be blue light.

[0104] In embodiments, the second light generating device may be configured to provide second device light in an optical path to the second diffuser assembly (via the second polarization-based redirection optical element. Hence, in embodiments, the second diffuser assembly may be configured downstream of the second light generating device.

[0105] The second diffuser assembly may thus be configured in a light-receiving relationship (via the second redirection optical element) with the second light generating device. In embodiments, the second diffuser assembly may thus be configured to receive at least part of the second device light (via the second redirection optical element). In embodiments, the second diffuser assembly may comprise (at least) a second diffuser. The second diffuser may, in embodiments, be configured to diffuse (or scatter) at least part of the second device light received by the second diffuser. Especially, in embodiments, the second diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the second device light received by the second diffuser into diffused second device light.

[0106] Similarly to the (first) diffuser assembly, in embodiments, the second diffuser assembly may be configured in the transmissive mode or in the reflective mode. Especially, 2024PF80236

[0107] 29 in embodiments, the second diffuser assembly (and thus the second diffuser) may be configured in the reflective mode. Therefore, in embodiments, the second diffuser may be (diffuse) reflective for second device light. Moreover, in embodiments, the second diffuser may comprise a polarization maintaining diffuser.

[0108] The second diffuser may, in embodiments, thus be configured to diffuse (or scatter) and reflect the second device light received by the second diffuser. Furthermore, in embodiments, the second diffuser assembly may comprise a second polarization converter. Embodiments of the second polarization converter may be similar as described above for the (first) polarization converter. Briefly, in embodiments, the second polarization converter may comprise a X / 4 waveplate configured in an optical path between (relative to the propagation of light through the system) the second redirection optical element and the second diffuser. As such, the quarter waveplate may, in embodiments, be configured to convert light received by the quarter waveplate having a linear polarization into light having the second elliptical (such as especially circular) polarization. At the diffuser, in embodiments, the light having the second elliptical polarization may be diffused into diffused light having the first elliptical (such as especially circular) polarization. Therefore, in embodiments, the quarter waveplate may also be configured to convert diffused light received by the quarter waveplate (via the diffuser) and having the first elliptical polarization into diffused light having a linear polarization. Hence, in embodiments, the second diffuser assembly may comprise an arrangement of a second polarization converter and a second diffuser.

[0109] Furthermore, in embodiments, the second diffuser assembly may comprise condensing and collecting (or collimating) optical elements. In embodiments, the condensing and collecting optical elements may be located in an optical path between the (reflective) second diffuser and the second redirection optical element (such as e.g. between the second diffuser and the second polarization converter).

[0110] As indicated above, in embodiments, the optical elements (especially the redirection optical elements) may thus also comprise a second redirection optical element.

[0111] The second redirection optical element may especially (in an operational mode of the light generating system) be configured downstream of the second light generating device. Especially, in embodiments, the second redirection optical element may be configured in an optical path between the second light generating device and the (reflective) second diffuser assembly. Hence, in embodiments, the second light generating device may especially be configured to provide second device light to the second redirection optical element. In such embodiments, the second redirection optical element may thus (during 2024PF80236

[0112] 30 operation) be configured in a light-receiving relationship with the second light generating device.

[0113] In embodiments, the second redirection optical element may comprise a polarization-based redirection optical element, i.e., may comprise a polarizing beam splitter (PBS2) or a reflective polarizer. Hence, in embodiments, the second redirection optical element may also be referred to as a second polarization-based redirection optical element. Embodiments of the second polarization-based redirection optical element may be similar as described above for the first polarization-based redirection optical element. However, the second redirection optical element may be configured to (re-)direct the light received by the second redirection optical element in a complementary way relative to the (re-)directing of the light received by the first redirection optical element.

[0114] Hence, in embodiments, the second device light reaching the second redirection optical element may comprise (at least) the first linear polarization (e.g. s- polarization). Conversely, in embodiments, the diffused second device light reaching the second redirection optical element may comprise (at least) the second linear polarization (e.g. s-polarization), different from the first linear polarization. In embodiments, the second redirection optical element may be configured to (re-)direct light received by the second redirection optical element. The second redirection optical element may especially do so in dependence of the polarization of the light received by the second redirection optical element.

[0115] In embodiments, the second redirection optical element may be configured to (re-)direct light received by the second redirection optical element and having the first linear polarization into an optical path to the second diffuser assembly. Especially, in embodiments, the second redirection optical element may be configured to (re-)direct (such as transmit or reflect) second device light received by the second redirection optical element and having the first linear polarization into an optical path to the second diffuser assembly.

[0116] Additionally, in embodiments, the second redirection optical element may be configured to (re-)direct the light received by the second redirection optical element and having the second linear polarization into an optical path to the light exit. Especially, in embodiments, the second redirection optical element may be configured to (re-)direct (such as reflect or transmit) the diffused second device light received by the second redirection optical element and having the second linear polarization into an optical path to the light exit.

[0117] The diffused second device light may thus, in embodiments, be directed towards the light exit. Therefore, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of the diffused second device 2024PF80236

[0118] 31 light. Hence, in specific embodiments, the light generating system further comprises a second light generating device, a second polarization based redirection optical element, and a second diffuser assembly, wherein: (A) the second light generating device is configured to generate second device light, wherein the second light generating device comprises a second solid- state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (B) the second diffuser assembly comprises a second diffuser and a second polarization converter; wherein the second diffuser comprises a polarization maintaining diffuser, wherein the second diffuser is configured in the reflective mode; wherein the second diffuser is configured to diffuse the second device light received by the second diffuser into diffused second device light; wherein the second polarization converter is configured in an optical path between the second polarization based redirection optical element and the second diffuser; wherein the second polarization converter is configured to convert linear polarized light received by the second polarization converter into elliptical polarized light and to convert elliptical polarized light received by the second polarization converter into linear polarized light; (C) the second polarization based redirection optical element is configured in a light-receiving relationship with the second light generating device; wherein the second polarization based redirection optical element is configured to (i) direct (ia) second device light received by the second polarization based redirection optical element and having the first linear polarization in an optical path to the second diffuser assembly, and to (ii) direct (iia) diffused second device light received by the second polarization based redirection optical element and having the second linear polarization in an optical path to the light exit; and (D) the system light in an operational mode of the light generating system further comprises at least part of the diffused second device light. Such embodiments may be beneficial as the addition of the diffused second device light may improve the optical power of the light generating system. Furthermore, such embodiments may be beneficial as a more cool white system light may be provided. Yet further, with such embodiments system light comprising both linear polarizations may be provided, which may be desirable for further upstream applications.

[0119] In embodiments, the diffused first device light, the diffused luminescent material light, and the diffused second device light may be combined into the same optical path to the light exit by additional optics, such as e.g. an additional polarizing beam splitter, or a semitransparent mirror.

[0120] Alternatively, in embodiments, the diffused first device light, the diffused luminescent material light, and the diffused second device light may be combined into the 2024PF80236

[0121] 32 same optical path to the light exit by the second redirection optical element. In such embodiments, the second redirection optical element may thus be configured in a lightreceiving relationship with both the second light generating device and the first redirection optical element. Similarly to the first redirection optical element, in embodiments, the second redirection optical element may comprise a polarizing beam splitter or a reflective polarizer. Hence, in specific embodiments, the second polarization-based redirection optical element may be configured in a light-receiving relationship with both the second light generating device and the first redirection optical element, wherein the second polarization based redirection optical element may be configured to (i) transmit diffused first device light having the first linear polarization, (ii) transmit diffused luminescent material light having the first linear polarization, and (iii) reflect the diffused second device light having the second linear polarization in an optical path to the light exit. Alternatively, in specific embodiments, the second polarization-based redirection optical element may be configured in a light-receiving relationship with both the second light generating device and the first redirection optical element, wherein the second polarization based redirection optical element may be configured to (i) reflect diffused first device light having the first linear polarization, (ii) reflect diffused luminescent material light having the first linear polarization, and (iii) transmit the diffused second device light having the second linear polarization in an optical path to the light exit. Such embodiments may be beneficial as no additional optical elements may be necessary, therewith keeping the system relatively compact and reducing costs.

[0122] Furthermore in embodiments, the light generating system may comprise a second arrangement comprising the second sub arrangement (i.e., the second light generating device, the second polarization based redirection optical element, and the second diffuser assembly (and optical elements, such as e.g. lenses)), a second luminescent material and a second reflective polarizer. Hence, in embodiments, the light generating system may comprise a second luminescent material and a second reflective polarizer.

[0123] The optical elements may, in embodiments, be configured to (re-)direct (or guide) second device light (generated by the second light generating device) to the second luminescent material. Additionally, in embodiments, the optical elements may be configured to (re-)direct (or guide) second device light and / or second luminescent material light (provided by the second luminescent material) to the second diffuser assembly. Yet additionally, in embodiments, the optical elements may be configured to (re-)direct (or guide) diffused second device light and / or diffused (second) luminescent material light (provided by the second diffuser assembly) to the light exit. Therefore, in embodiments, the second 2024PF80236

[0124] 33 arrangement (especially the optical elements) may comprise at least a second (polarizationbased) redirection optical element. Furthermore, in embodiments, the second arrangement (especially the optical elements) may comprise a second reflective polarizer.

[0125] In embodiments, the second light generating device may be configured to provide second device light in an optical path to the second luminescent material. Hence, in embodiments, the second luminescent material may be configured downstream of (especially in a light-receiving relationship with) the second light generating device. In embodiments, the second luminescent material may be configured to convert at least part of the second device light received by the second luminescent material into second luminescent material light.

[0126] In embodiments, the second luminescent material may be configured to convert at least part of the second device light received by the second luminescent material into second luminescent material light. Especially, in embodiments, the second luminescent material may be configured to convert at least 50%, like at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the second device light received by the second luminescent material into first luminescent material light. In specific embodiments, the second luminescent material may be configured to convert at least 95%, like at least 98%, such as at least 99%, including essentially 100% of the second device light received by the second luminescent material into second luminescent material light. Hence, in such embodiments, the second luminescent material may be configured in a full conversion mode. In such embodiments, the light generating system may be configured to generate system light comprising (diffused) first luminescent material light and (diffused) second luminescent material light. However, in alternative embodiments, the light generating system may be configured to generate system light also comprising diffused second device light. Hence, in embodiments, the second luminescent material may be configured to convert at most 100%, such as at most 98%, especially at most 95%, more especially at most 90% of the second device light received by the second luminescent material into second luminescent material light.

[0127] Moreover, in embodiments, the second luminescent material may be configured to (scatter and) transmit at least part of the second device light received by the second luminescent material in an optical path to the second diffuser assembly. Hence, in such embodiments, at least part of the second device light received by the second luminescent material may be transmitted as unconverted second device light, such that (unconverted) second device light may propagate in an optical path to the second diffuser assembly. Especially, in embodiments, the second luminescent material may be configured to 2024PF80236

[0128] 34

[0129] (scatter and) transmit at least 2%, like at least 3%, such as at least 5%, especially at least 10%, more especially at least 20% of the second device light received by the second luminescent material (as unconverted second device light) in an optical path (via the second reflective polarizer) to the second diffuser assembly. Further, in embodiments, the second luminescent material may be configured to convert at most 50%, such as at most 40%, especially at most 30%, more especially at most 25% of the second device light received by the second luminescent material (as unconverted second device light) in an optical path to the second diffuser assembly. Such embodiments may be beneficial as the light generating system may thus be configured to generate system light having an improved spectral power distribution.

[0130] In embodiments, the second luminescent material may comprise any one of the above described types of luminescent material. Moreover, in embodiments, the second luminescent material may comprise multiple one or more different luminescent materials. In some embodiments, the first luminescent material and the second luminescent material may comprise (such as be) essentially the same type of luminescent material. In alternative embodiments, the first luminescent material and the second luminescent material may differ. Therefore, in such embodiments, the first luminescent material light and the second luminescent material light may have different spectral power distributions.

[0131] Especially, in embodiments, the second luminescent material may be configured to convert second device light received by the second luminescent material into second luminescent material light. In specific embodiments, the second luminescent material light may have a second luminescent material centroid wavelength (XCLM2). Especially, in embodiments, the second luminescent material centroid wavelength (Aci. ) may be selected from the range of 490-620 nm, such as from the range of 500-600 nm, like from the range of 520-590 nm, especially from the range of 535-580 nm. Hence, in embodiments, the second luminescent material light may comprise, such as be, one or more of yellow light and green light, such as especially yellow light. Alternatively, in embodiments, the second luminescent material centroid wavelength (Aci. ) may be selected from the range of 600-660 nm, like from the range of 610-650 nm, such as from the range of 620-640 nm. Hence, in embodiments, the second luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light.

[0132] Further, in embodiments, the first luminescent material centroid wavelength (XCLMI) may be different from the second luminescent material centroid wavelength (Aci. ). Especially, in embodiments, |XCLMI-XCLM2|>5 nm, such as |XCLMI-XCLM2|>10 nm, like |XCLMI- 2024PF80236

[0133] 35 CLM2|>15 nm, especially, |XCLMI- CLM2|>20 nm. Moreover, in embodiments, |XCLMI- CLM2|<150 nm, like |XcLMi-kcLM2|>100 nm. Such embodiments may be beneficial as the combination of the first luminescent material light and the second luminescent material light may (if their centroid wavelengths significantly differ) provide an improved spectral power distribution and color rendering of the system light.

[0134] In embodiments, the second luminescent material may be configured in the transmissive mode. In alternative embodiments, the second luminescent material may be configured in the reflective mode.

[0135] As mentioned above, the light generating system may comprise further optical elements. In embodiments, the optical elements may at least comprise a second reflective polarizer. The second reflective polarizer may, in embodiments, be configured in an optical path between the second luminescent material and the second diffuser assembly. As such, the second reflective polarizer may be configured in a light-receiving relationship with the second luminescent material. Especially, in embodiments, second the reflective polarizer may be configured to receive the second device light and the second luminescent material light propagating from the second luminescent material. In embodiments, the second reflective polarizer may be transmissive for a (main) linear polarization of the (second device and / or second luminescent material) light propagating in the direction of the second diffuser assembly, while being light reflective for a (minor) linear polarization of the (second device and / or second luminescent material) light. Especially, in embodiments, the second reflective polarizer may be configured to reflect light (received by the second reflective polarizer and) having the second linear polarization and to transmit light (received by the second reflective polarizer and) having the first linear polarization.

[0136] Hence, in embodiments, the second device light reaching the second reflective polarizer (via the second luminescent material) may comprise polarized light. Similarly, in embodiments, in embodiments, the second luminescent material light reaching the second reflective polarizer may comprise polarized light. Yet, the light generating system may be configured such that the second device light and the second luminescent material light reaching the second reflective polarizer (via the second luminescent material) may comprise linear polarized light. Hence, the second device light may comprise linear polarized light and / or a polarizer may be configured downstream of the second light generating device (and upstream of the second luminescent material) such that the second device light and the second luminescent material light reaching the second reflective polarizer may comprise linear polarized light. 2024PF80236

[0137] 36

[0138] In embodiments, the second reflective polarizer may be configured to reflect light having the second linear polarization back to the second luminescent material. Conversely, in embodiments, the second reflective polarizer may be configured to transmit (only) light having the first linear polarization in an optical path to the second diffuser assembly.

[0139] The second reflective polarizer may then, in embodiments, be configured to reflect second device light received by the second reflective polarizer and having the second linear polarization back to the second luminescent material. Similarly, in embodiments, the second reflective polarizer may be configured to reflect second luminescent material light received by the second reflective polarizer and having the second linear polarization back to the second luminescent material. At the second luminescent material, this light having the second linear polarization may then be re-converted and re-emitted in an optical path to the second reflective polarizer.

[0140] Further, in embodiments, the second reflective polarizer may be configured to transmit second device light received by the second reflective polarizer and having the first linear polarization in an optical path to the second diffuser assembly. Similarly, in embodiments, the second reflective polarizer may be configured to reflect second luminescent material light received by the second reflective polarizer and having the first linear polarization in an optical path to the second diffuser assembly.

[0141] In embodiments, the second diffuser assembly may thus be configured to receive at least part of the second luminescent material light (via the second luminescent material and (some of) the optical elements). The second diffuser may, in embodiments, be configured to diffuse (or scatter) at least part of the second luminescent material light received by the second diffuser. Especially, in embodiments, the second diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the second luminescent material light received by the second diffuser into diffused (second) luminescent material light.

[0142] The second redirection optical element may especially (in an operational mode of the light generating system) be configured downstream of the second light generating device. Especially, in embodiments, the second redirection optical element may be configured in an optical path between the second reflective polarizer and the second (reflective) diffuser assembly. Moreover, in embodiments, the second luminescent material may especially be configured to provide second luminescent material light (and second device light) to the second redirection optical element (via the second reflective polarizer). In 2024PF80236

[0143] 37 such embodiments, the second redirection optical element may thus (during operation) be configured in a light-receiving relationship with the second luminescent material.

[0144] In embodiments, the second device light and / or the second luminescent material light reaching the second redirection optical element may comprise (at least) the first linear polarization (e.g. s-polarization). Conversely, in embodiments, the diffused second device light and / or the diffused (second) luminescent material light reaching the second redirection optical element may comprise (at least) the second linear polarization (e.g. p- polarization).

[0145] In embodiments, the second redirection optical element may be configured to (re-)direct (such as transmit or reflect) second luminescent material light received by the second redirection optical element and having the first linear polarization into an optical path to the second diffuser assembly. Additionally, in embodiments, the second redirection optical element may be configured to (re-)direct (such as reflect or transmit) the diffused (second) luminescent material light received by the second redirection optical element and having the second linear polarization into an optical path to the light exit.

[0146] In specific embodiments, the second polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) transmit second device light having the first linear polarization, (ii) transmit second luminescent material light having the first linear polarization, (iii) reflect the diffused second device light having the second linear polarization, and (iv) reflect the diffused second luminescent material light having the second linear polarization. Alternatively, in specific embodiments, the second polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) reflect second device light having the first linear polarization, (ii) reflect second luminescent material light having the first linear polarization, (iii) transmit the diffused second device light having the second linear polarization, and (iv) transmit the diffused second luminescent material light having the second linear polarization. Such embodiments may be beneficial as the second redirection optical element may thus efficiently separate the beams of undiffused light from the beams of diffused light.

[0147] As described above, the second redirection optical element may thus be configured to direct the diffused second device light and( / or) the diffused second luminescent material light in a same optical path to the light exit. Therefore, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of the diffused second luminescent material light. Especially, in embodiments, in an operational 2024PF80236

[0148] 38 mode of the light generating system the system light may comprise at least part of the diffused second luminescent material light and at least part of the diffused second device light.

[0149] The light generating system may further, in embodiments, comprise another subarrangement (also referred to as third subarrangement) comprising a third light generating device, a third polarization based redirection optical element, and a third diffuser assembly (and optical elements, such as e.g. lenses).

[0150] In embodiments, the light generating devices may thus comprise the third light generating device. The third light generating device may, in embodiments, be configured to generate third device light. Therefore, in embodiments, the third light generating device may comprise a third light source. The second light source may be essentially any light source, see also further below. Especially, in embodiments, the (third light source of the) third light generating device may comprise a third solid state light source. Hence, in embodiments, the third light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The third light generating device may herein also comprise a plurality of third (solid state) light sources. Especially, in specific embodiments, the third light generating device may comprise a third laser bank. In such embodiments, the third laser bank may comprise a third array comprising a plurality of third solid state light sources. Especially, in embodiments, the third laser bank may comprise a second array comprising a plurality of third lasers (similarly to the first laser bank described above).

[0151] Further, in embodiments, the third light generating device may especially be configured to generate third device light having a third centroid wavelength (Acs). Especially, in embodiments, (at least part of) the third device light may have a third centroid wavelength (Acs) selected from the wavelength range of 490-590 nm, such as from the range of 500-580 nm, like from the range of 500-570 nm. More especially, in embodiments, (at least part of) the third device light may have a third centroid wavelength (A ) selected from the wavelength range of 510-560 nm, such as from the wavelength range of 520-550 nm. Hence, in embodiments, in an operational mode of the light generating system, the third device light may be yellow or green light.

[0152] In embodiments, the third light generating device may be configured to provide third device light in an optical path to the third diffuser assembly (via the third polarization-based redirection optical element. Hence, in embodiments, the third diffuser assembly may be configured downstream of the third light generating device. 2024PF80236

[0153] 39

[0154] The third diffuser assembly may thus be configured in a light-receiving relationship (via the third redirection optical element) with the third light generating device. In embodiments, the third diffuser assembly may thus be configured to receive at least part of the third device light (via the third redirection optical element). In embodiments, the third diffuser assembly may comprise (at least) a third diffuser. The third diffuser may, in embodiments, be configured to diffuse (or scatter) at least part of the third device light received by the third diffuser. Especially, in embodiments, the third diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the third device light received by the third diffuser into diffused third device light.

[0155] Similarly to the (first and second) diffuser assembly, in embodiments, the third diffuser assembly may be configured in the transmissive mode or in the reflective mode. Especially, in embodiments, the third diffuser assembly (and thus the third diffuser) may be configured in the reflective mode. Therefore, in embodiments, the third diffuser may be (diffuse) reflective for third device light. Moreover, in embodiments, the third diffuser may comprise a polarization maintaining diffuser.

[0156] The third diffuser may, in embodiments, thus be configured to diffuse (or scatter) and reflect the third device light received by the third diffuser. Furthermore, in embodiments, the third diffuser assembly may comprise a third polarization converter. Embodiments of the third polarization converter may be similar as described above for the (first and second) polarization converter. Briefly, in embodiments, the third polarization converter may comprise a X / 4 waveplate configured in an optical path between (relative to the propagation of light through the system) the third redirection optical element and the third diffuser. As such, the quarter waveplate may, in embodiments, be configured to convert light received by the quarter waveplate having a linear polarization into light having the (first or second) elliptical (such as especially circular) polarization. At the diffuser, in embodiments, the light having the (first or second) elliptical polarization may be diffused into diffused light having the (second or first) elliptical (such as especially circular) polarization. Therefore, in embodiments, the quarter waveplate may also be configured to convert diffused light received by the quarter waveplate (via the diffuser) and having the (second or first) elliptical polarization into diffused light having a linear polarization. Hence, in embodiments, the third diffuser assembly may comprise an arrangement of a third polarization converter and a third diffuser. 2024PF80236

[0157] 40

[0158] Furthermore, in embodiments, the third diffuser assembly may comprise condensing and collecting (or collimating) optical elements. In embodiments, the condensing and collecting optical elements may be located in an optical path between the (reflective) third diffuser and the third redirection optical element (such as e.g. between the third diffuser and the third polarization converter).

[0159] As indicated above, in embodiments, the optical elements (especially the redirection optical elements) may thus also comprise a third redirection optical element.

[0160] The third redirection optical element may especially (in an operational mode of the light generating system) be configured downstream of the third light generating device. Especially, in embodiments, the third redirection optical element may be configured in an optical path between the third light generating device and the (reflective) third diffuser assembly. Hence, in embodiments, the third light generating device may especially be configured to provide third device light to the third redirection optical element. In such embodiments, the third redirection optical element may thus (during operation) be configured in a light-receiving relationship with the third light generating device.

[0161] In embodiments, the third redirection optical element may comprise a polarization-based redirection optical element, i.e., may comprise a polarizing beam splitter (PBS3) or a reflective polarizer. Hence, in embodiments, the third redirection optical element may also be referred to as a third polarization-based redirection optical element. Embodiments of the third polarization-based redirection optical element may be similar as described above for the first and second polarization-based redirection optical element.

[0162] Hence, in embodiments, the third device light reaching the third redirection optical element may comprise (at least) the first or second linear polarization. Conversely, in embodiments, the diffused third device light reaching the third redirection optical element may comprise (at least) the other one of the first or second linear polarization. In embodiments, the third redirection optical element may be configured to (re-)direct light received by the third redirection optical element. The third redirection optical element may especially do so in dependence of the polarization of the light received by the third redirection optical element.

[0163] In embodiments, the third redirection optical element may be configured to (re-)direct light received by the third redirection optical element and having the first or second linear polarization into an optical path to the third diffuser assembly. Especially, in embodiments, the third redirection optical element may be configured to (re-)direct (such as transmit or reflect) third device light received by the third redirection optical element and 2024PF80236

[0164] 41 having the first or second linear polarization into an optical path to the third diffuser assembly.

[0165] Additionally, in embodiments, the third redirection optical element may be configured to (re-)direct the light received by the third redirection optical element and having the other one of the first or second linear polarization into an optical path to the light exit. Especially, in embodiments, the third redirection optical element may be configured to (redirect (such as reflect or transmit) the diffused third device light received by the third redirection optical element and having the other one of the first and second linear polarization into an optical path to the light exit.

[0166] The diffused third device light may thus, in embodiments, be directed towards the light exit. Therefore, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of the diffused third device light. Hence, in specific embodiments, the light generating system further comprises a third light generating device, a third polarization based redirection optical element, and a third diffuser assembly, wherein: (A) the third light generating device is configured to generate third device light, wherein the third light generating device comprises a third solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multijunction light-emitting diodes; (B) the third diffuser assembly comprises a third diffuser and a third polarization converter; wherein the third diffuser comprises a polarization maintaining diffuser, wherein the third diffuser is configured in the reflective mode; wherein the third diffuser is configured to diffuse the third device light received by the third diffuser into diffused third device light; wherein the third polarization converter is configured in an optical path between the third polarization based redirection optical element and the third diffuser; wherein the third polarization converter is configured to convert linear polarized light received by the third polarization converter into elliptical polarized light and to convert elliptical polarized light received by the third polarization converter into linear polarized light; (C) the third polarization based redirection optical element is configured in a lightreceiving relationship with the third light generating device; wherein the third polarization based redirection optical element is configured to (i) direct (ia) third device light received by the third polarization based redirection optical element and having the first linear polarization in an optical path to the third diffuser assembly, and to (ii) direct (iia) diffused third device light received by the third polarization based redirection optical element and having the second linear polarization in an optical path to the light exit; and (D) the system light in an operational mode of the light generating system further comprises at least part of the diffused 2024PF80236

[0167] 42 third device light. Such embodiments may be beneficial as the addition of the diffused third device light may improve the spectral power distribution and color rendering of the light generating system. Furthermore, such embodiments may be beneficial as a more high- brightness white system light may be provided.

[0168] In embodiments, the diffused first device light, the diffused luminescent material light, and one or both of the diffused second device light and the diffused third device light may be combined into the same optical path to the light exit by additional optics, such as e.g. an additional polarizing beam splitter, or a semitransparent mirror.

[0169] Especially, in embodiments, the optical elements may comprise a fourth redirection optical element. In embodiments, the fourth redirection optical element may especially comprise a fourth dichroic-based (or spectral-based) redirection optical element. The fourth redirection optical element may, in embodiments, be configured downstream of (all of) the first polarization based redirection optical element, the second polarization based redirection optical element, and the third polarization based redirection optical element. As such, in embodiments, the fourth redirection optical element may be configured in a lightreceiving relationship with the diffused first device light, the diffused second device light, the diffused third device light, and the diffused (first and / or second) luminescent material light. Especially, in embodiments, the fourth redirection optical element may be configured to direct (all of) the diffused first device light, the diffused luminescent material light, the diffused second device light, and the diffused third device light received by the fourth dichroic based redirection optical element into the same optical path to the light exit. Therefore, in embodiments, the fourth dichroic-based redirection optical element may comprise at least one cut-off wavelength, i.e., the dichroic beam combiner may be configured to transmit light having one of a wavelength above or below the cut-off wavelength and to reflect light having the other one of a wavelength above or below the cut-off wavelength. Note that therein, the term “dichroic beam combiner” may refer to a dichroic (or spectral) filter as described above, i.e., having one or more cut-off wavelengths. However, herein the term “dichroic beam combiner” may also refer to a combination of an optical component, such as e.g. a polarizing beam splitter, with further spectral requirements. For example, in embodiments, the fourth redirection optical element may comprise (i) a polarizing beam splitter having PBS-functionality for blue (or red) light combined with (ii) transmissive properties for yellow-green and red (or blue) light (referred to as dichroic beam combiner). Note that, in such embodiments, the spectral requirements imposed by the dichroic beam combiner may apply to (only) one of the (linear) polarizations, but not for its complementary 2024PF80236

[0170] 43

[0171] (e.g. orthogonal linear) polarization. Herein, such a component comprising a combination of an optical component, such as e.g. a polarizing beam splitter, with further spectral requirements may be described as a combined polarizing beam splitter and dichroic beam combiner.

[0172] In embodiments, the fourth redirection optical element may thus have at least one cut-off wavelength. For example, in embodiments, the at least one of the one or more cut-off wavelengths may be selected from the range of 380-780 nm, such as from the range of 400-580 nm, like from the range of 430-550 nm. Alternatively, in embodiments, at least one of the one or more cut-off wavelengths may be selected from the range of 380-780 nm, such as from the range of 500-750 nm, like from the range of 570-700 nm.

[0173] For example, in embodiments, the fourth redirection optical element may be configured to (i) transmit the (blue) diffused first device light, the (blue) diffused second device light, and the (green-yellow) diffused luminescent material light, and (ii) reflect the (red) diffused third device light, or vice versa. In an alternative example, in embodiments, the fourth redirection optical element may be configured to (i) transmit the (blue) diffused first device light and the (blue) diffused second device light, and (ii) reflect the (green-yellow) diffused luminescent material light and the (red) diffused third device light, or vice versa. Note that, in embodiments, one or more of the different types of light may already be provided into the same optical path to the light exit by another one of the redirection optical elements. For example, in embodiments, the second redirection optical element may be configured to combine the diffused first device light, the diffused second device light, and the diffused luminescent material light. In such embodiments, the fourth redirection optical element may then be configured to combine (into the same optical path to the light exit) said combined light with the diffused third redirection optical element. Such embodiments may be beneficial as no additional optical elements may be necessary, therewith keeping the system relatively compact and reducing costs.

[0174] Alternatively, in embodiments, the diffused first device light, the diffused luminescent material light, and (one or) both of the diffused second device light and the diffused third device light may be combined into the same optical path to the light exit by the third redirection optical element. In such embodiments, the third redirection optical element may thus be configured in a light-receiving relationship with both the third light generating device (, the first redirection optical element) and the second redirection optical element. Here, in embodiments, the third redirection optical element may comprise a narrow-band polarizing beam splitter. Especially, in such embodiments, the third redirection optical 2024PF80236

[0175] 44 element may comprise a narrow-band polarizing beam splitter having polarization-based splitting functionality for (specifically, such as only) the third centroid wavelength (Acs). As such, in embodiments, the narrow-band polarizing beam splitter may be configured to (i) transmit (ia) at least part of the diffused second device light received by the partially polarizing beam splitter, (ib) at least part of the third device light received by the partially polarizing beam splitter and having one of the first linear polarization and the second linear polarization, (ic) at least part of the diffused first device light received by the partially polarizing beam splitter, (id) and diffused luminescent material light received by the partially polarizing beam splitter in an optical path to the light exit, and to (ii) reflect at least part of the diffused third device light received by the partially polarizing beam splitter and having the other one of the first linear polarization and the second linear polarization in an optical path to the light exit. Alternatively, in such embodiments, the narrow-band polarizing beam splitter may be configured to (i) reflect (ia) at least part of the diffused second device light received by the partially polarizing beam splitter, (ib) at least part of the third device light received by the partially polarizing beam splitter and having one of the first linear polarization and the second linear polarization, (ic) at least part of the diffused first device light received by the partially polarizing beam splitter, (id) and diffused luminescent material light received by the partially polarizing beam splitter in an optical path to the light exit, and to (ii) transmit at least part of the diffused third device light received by the partially polarizing beam splitter and having the other one of the first linear polarization and the second linear polarization in an optical path to the light exit.

[0176] Yet alternatively, in embodiments, the diffused first device light, the diffused luminescent material light, and one or both of the diffused second device light and the diffused third device light may be combined into the same optical path to the light exit by the third redirection optical element. In such embodiments, the third redirection optical element may thus be configured in a light-receiving relationship with both the third light generating device (, the first redirection optical element) and the second redirection optical element. Here, in embodiments, the third redirection optical element may comprise a partially polarizing beam splitter. Hence, in specific embodiments, the third polarization based redirection optical element comprises a partially polarizing beam splitter, wherein the partially polarizing beam splitter is configured in a light-receiving relationship with the third light generating device, the third diffuser assembly, and the second polarization based redirection optical element; wherein the partially polarizing beam splitter is configured to (i) transmit (ia) at least part of the diffused second device light received by the partially 2024PF80236

[0177] 45 polarizing beam splitter and having the second linear polarization, (ib) at least part of the third device light received by the partially polarizing beam splitter and having the second linear polarization, (ic) at least part of the diffused first device light received by the partially polarizing beam splitter and having the first linear polarization, (id) and diffused luminescent material light received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit, and to (ii) reflect at least part of the diffused third device light received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit.

[0178] Alternatively, in specific embodiments, the third polarization based redirection optical element comprises a partially polarizing beam splitter, wherein the partially polarizing beam splitter is configured in a light-receiving relationship with the third light generating device, the third diffuser assembly, and the second polarization based redirection optical element; wherein the partially polarizing beam splitter is configured to (i) transmit (ia) at least part of the diffused first device light received by the partially polarizing beam splitter and having the first linear polarization, (ib) at least part of the diffused luminescent material light received by the partially polarizing beam splitter and having the first linear polarization, (ic) at least part of the third device light received by the partially polarizing beam splitter and having the first linear polarization, and (id) at least part of the diffused second device light received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit, and to (ii) reflect at least part of the diffused third device light received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit. For example, in embodiments, the partially polarizing beam splitter may be configured to transmit x% of light having the first linear polarization and to reflect 100-x% of light having the first linear polarization, wherein x may be selected from the range of 20-80, such as from the range of 30-70, like from the range of 40-60. Similarly, in embodiments, the partially polarizing beam splitter may be configured to transmit y% of light having the second linear polarization and to reflect 100-y% of light having the second linear polarization, wherein y may be selected from the range of 20-80, such as from the range of 30-70, like from the range of 40-60. Such embodiments may be beneficial as no additional optical elements may be necessary, therewith keeping the system relatively compact and reducing costs.

[0179] In embodiments, (the first arrangement of the) light generating system may also (instead of or in combination with one of the other (sub)arrangements) comprise a fourth light generating device. In embodiments, the light generating devices may thus further 2024PF80236

[0180] 46 comprise the fourth light generating device. The fourth light generating device may, in embodiments, be configured to generate fourth device light. Therefore, in embodiments, the fourth light generating device may comprise a fourth light source. The fourth light source may be essentially any light source, see also further below. Especially, in embodiments, the (fourth light source of the) fourth light generating device may comprise a fourth solid state light source. Hence, in embodiments, the fourth light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The fourth light generating device may herein also comprise a plurality of fourth (solid state) light sources. Especially, in specific embodiments, the fourth light generating device may comprise a fourth laser bank. In such embodiments, the fourth laser bank may comprise a fourth array comprising a plurality of fourth solid state light sources. Especially, in embodiments, the fourth laser bank may comprise a fourth array comprising a plurality of fourth lasers (similarly to the first laser bank described above).

[0181] Further, in embodiments, the fourth light generating device may especially be configured to generate fourth device light having a fourth centroid wavelength (Xc4). Especially, in embodiments, (at least part of) the fourth device light may have a fourth centroid wavelength (Xc4) selected from the wavelength range of 500-780 nm, such as from the range of 500-590 nm, like from the range of 510-570 nm. Hence, in embodiments, in an operational mode of the light generating system, the fourth device light may be yellow or green light. More especially, in embodiments, (at least part of) the fourth device light may have a fourth centroid wavelength (Xc4) selected from the wavelength range of 590-780 nm, such as from the wavelength range of 600-760 nm, like from the wavelength range of 620- 700 nm. Hence, in embodiments, in an operational mode of the light generating system, the fourth device light may be orange or red light.

[0182] Further, in embodiments, the first centroid wavelength (Xci) may be different from the fourth centroid wavelength (Xc4). Especially, in embodiments, |Xci-kc4|>5 nm, such as |Xci-kc4|>l 0 nm, like |Xci-Xc4|>l 5 nm, especially, |Xci-kc4|>20 nm. Moreover, in embodiments, |Xci-Xc4|<l 50 nm, like |Xci-kc4|>100 nm. Such embodiments may be beneficial as the combination of the first device light and the fourth device light may (if their centroid wavelengths significantly differ) provide an improved spectral power distribution and color rendering of the system light.

[0183] In embodiments, the fourth light generating system may (also) be configured upstream of the first luminescent material. Therefore, in embodiments where the light generating system comprises the fourth light generating device, the light generating system 2024PF80236

[0184] 47 may further comprise a fifth redirection optical element. Especially, in embodiments, the fifth redirection optical element may comprise a fifth dichroic-based (or spectral-based) redirection optical element.

[0185] The fifth redirection optical element may, in embodiments, be configured in a light-receiving relationship with the first light generating device and the fourth light generating device. Especially, in embodiments, the fifth redirection optical element may be configured to direct both first device light and fourth device light received by the fifth redirection optical element in an optical path to the first luminescent material. In such embodiments, the first light generating device, the fourth light generating device, and the fifth redirection optical element may be configured such that the first device light and the fourth device light may be (incident on or) received by the fifth redirection optical element from (substantially) orthogonal directions. Therefore, in embodiments, the fifth redirection optical element may be configured (i) to transmit one of the first device light and the fourth device light received by the fifth redirection optical element and (ii) to reflect the other one of the first device light and the fourth device light received by the fifth redirection optical element. The fifth redirection optical element may especially do so in dependence of the spectral power distribution of the device light received by the fifth redirection optical element. For example, in embodiments, the fifth redirection optical element may be configured (i) to transmit the first device light received by the fifth redirection optical element and having a wavelength (e.g. in the blue wavelength range) below a cut-off wavelength of the fifth redirection optical element, and (ii) to reflect the fourth device light received by the fifth redirection optical element and having a wavelength (e.g. in the green or even red wavelength range) above a cut-off wavelength of the fifth redirection optical element, or vice versa.

[0186] Further, in such embodiments, the first luminescent material may be configured to transmit at least part of the fourth device light received by the first luminescent material in an optical path to the diffuser assembly. Especially, in embodiments, the first luminescent material may be configured to transmit at least 50%, like at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the fourth device light received by the first luminescent material (as unconverted fourth device light) in an optical path to the diffuser assembly.

[0187] Additionally or alternatively, in such embodiments, the first luminescent material may be configured to convert at least part of the fourth device light received by the first luminescent material into fourth luminescent material light. Especially, in embodiments, 2024PF80236

[0188] 48 the first luminescent material may be configured to convert at least 50%, like at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the fourth device light received by the first luminescent material into fourth luminescent material light.

[0189] Yet further, in embodiments, the reflective polarizer may be configured to transmit fourth device light (and / or fourth luminescent material light) received by the reflective polarizer and having the second linear polarization. Hence, in embodiments, the fourth device light (and / or fourth luminescent material light) may (also) comprise polarized light. Especially, in embodiments, the reflective polarizer may be configured to transmit fourth device light (and / or fourth luminescent material light) received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly. Moreover, in such embodiments, the reflective polarizer may be configured to reflect fourth device light (and / or fourth luminescent material light) received by the reflective polarizer and having the first linear polarization. Especially, in embodiments, the reflective polarizer may be configured to reflect fourth device light (and / or fourth luminescent material light) received by the reflective polarizer and having the first linear polarization back to the first luminescent material.

[0190] The diffuser assembly may thus be configured to receive fourth device light(and / or fourth luminescent material light) having the second linear polarization from the reflective polarizer (via the first redirection optical element, see also further below). The (first) diffuser may thus additionally, in embodiments, be configured to diffuse (or scatter) at least part of the (fourth device and / or fourth luminescent material) light received by the diffuser. Especially, in embodiments, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the fourth device light received by the diffuser into diffused fourth device light. Similarly, in some embodiments, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the fourth luminescent material light received by the diffuser into diffused (fourth) luminescent material light.

[0191] In embodiments, as indicated above, the first redirection optical element may be configured to (re-)direct light received by the first redirection optical element and having the second linear polarization into an optical path to the diffuser assembly. Especially, in embodiments, the first redirection optical element may be configured to (re-)direct (such as transmit or reflect) (fourth) luminescent material light received by the first redirection optical element and having the second linear polarization into an optical path to the diffuser assembly. Moreover, in embodiments, the first redirection optical element may be configured 2024PF80236

[0192] 49 to (re-)direct (such as transmit or reflect) (unconverted) fourth device light received by the first redirection optical element and having the second linear polarization into an optical path to the diffuser assembly.

[0193] Additionally, in embodiments, the first redirection optical element may be configured to (re-)direct the light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit. Especially, in embodiments, the first redirection optical element may be configured to (re-)direct (such as reflect or transmit) the diffused (fourth) luminescent material light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit. Moreover, in embodiments, the first redirection optical element may be configured to (redirect (such as reflect or transmit) the diffused fourth device light received by the first redirection optical element and having the first linear polarization into an optical path to the light exit.

[0194] In specific embodiments, the first polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) transmit fourth device light having the second linear polarization, (ii) transmit fourth luminescent material light having the second linear polarization, (iii) reflect the diffused fourth device light having the first linear polarization, and (iv) reflect the diffused fourth luminescent material light having the first linear polarization. Alternatively, in specific embodiments, the first polarization-based redirection optical element may comprise a polarizing beam splitter or a reflective polarizer configured to (i) reflect fourth device light having the second linear polarization, (ii) reflect fourth luminescent material light having the second linear polarization, (iii) transmit the diffused fourth device light having the first linear polarization, and (iv) transmit the diffused fourth luminescent material light having the first linear polarization. Such embodiments may be beneficial as the first redirection optical element may thus efficiently separate the beams of undiffused light from the beams of diffused light.

[0195] As described above, the first redirection optical element may be configured to direct the diffused fourth device light and( / or) the diffused (fourth) luminescent material light in a same optical path to the light exit. Especially, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of the diffused fourth device light. Additionally, in embodiments, in an operational mode of the light generating system the system light may comprise at least part of (fourth) luminescent material light. Hence, in specific embodiments, the first device light has a first centroid wavelength (Xci), 2024PF80236

[0196] 50 wherein the light generating system further comprises a fourth light generating device and a fifth dichroic-based redirection optical element, wherein: (A) the fourth light generating device is configured to generate fourth device light having a fourth centroid wavelength (Xc4), wherein |Xci-Xc4|>l 0 nm; wherein the fourth light generating device comprises a fourth solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (B) the fifth dichroic-based redirection optical element is configured in a light-receiving relationship with the first light generating device and the fourth light generating device; wherein the fifth dichroic-based redirection optical element is configured to (i) direct both the first device light and the fourth device light (orthogonally) received by the fifth dichroic-based redirection optical element in an optical path to the first luminescent material; (C) the first luminescent material is configured to transmit at least part of the fourth device light received by the first luminescent material (in an optical path to the diffuser assembly); (D) the reflective polarizer is configured to transmit fourth device light received by the reflective polarizer and having the second linear polarization in an optical path to the diffuser assembly; (E) the diffuser is configured to diffuse the fourth device light received by the diffuser into diffused fourth device light; (F) the first polarization based redirection optical element is configured to (i) direct the (unconverted) fourth device light received by the first polarization based redirection optical element and having the second linear polarization in an optical path to the diffuser assembly, and to (ii) direct diffused fourth device light received by the first polarization based redirection optical element and having the first linear polarization in an optical path to the light exit; and (G) the system light in an operational mode of the light generating system further comprises at least part of the diffused fourth device light. Such embodiments may be beneficial as the spectral power distribution and color rendering of the system light may be significantly improved without significantly adding to the bulk and cost of the light generating system. Note that, in embodiments, the fourth light generating device and the fifth redirection optical element may also be configured in one of the other (sub)arrangements, such as e.g. the second subarrangement. In such embodiments, the fifth redirection optical element may be configured to provide a combination of second device light and fourth device light into an optical path to the second diffuser assembly. Hence, in such embodiments, the second diffuser assembly may be configured to provide diffused second device light and diffused fourth device light. Moreover, in such embodiments, the optical elements (such as the second redirection optical element) may be configured to provide the fourth device light to the second diffuser assembly and to direct the diffused 2024PF80236

[0197] 51 fourth device light in an optical path to the light exit. Other variations of the configuration comprising the herein described optical elements may be possible as well.

[0198] Furthermore, in embodiments, the light generating system may comprise a control system. In embodiments, the control system may especially be configured to control the color point (or spectral power distribution) of the system light. Additionally or alternatively, in embodiments, the control system may be configured to control the correlated color temperature of the system light. Additionally or alternatively, in embodiments, the control system may be configured to control the color rendering index of the system light.

[0199] Especially, in embodiments, the control system may be configured to control the optical characteristics (such as spectral power distribution, CCT, etc.) of the system light by controlling the light generating devices. In embodiments, the control system may be configured to control the optical characteristics (such as spectral power distribution, CCT, etc.) of the system light in dependence of one or more of an input signal of a user interface, a sensor signal, and a timer.

[0200] Yet additionally or alternatively, in embodiments, the light generating system may comprise a movement element. The movement element may, in embodiments, be configured to (move, especially) rotate (at least) the reflective polarizer (about its optical axis). Therefore, in embodiments, the movement element may e.g. comprise an actuator. In embodiments, the control system may be configured to control the movement element. As such, in embodiments, the control system may be configured to control (movement, especially) rotation of the reflective polarizer by controlling the movement element. By changing the orientation of the reflective polarizer relative to upstream light generating devices, the polarization of said device light propagating from the reflective polarizer to the receiving optics (such as propagating to the first redirection optical element) may change. The control system may thus, in embodiments, be configured to control one or more of (i) the color point of the system light, (ii) the color rendering index of the system light, and (iii) the correlated color temperature of the system light by controlling the movement element. Hence, in embodiments, the light generating system may further comprise a control system, wherein one or more of the following applies: (A) the control system may be configured to control one or more of (i) the color point of the system light, (ii) the color rendering index of the system light, and (iii) the correlated color temperature of the system light by controlling the light generating devices; and (B) the light generating system may further comprise a movement element configured to rotate the reflective polarizer (about its optical axis), and wherein the control system may be configured to control one or more of (i) the color point of 2024PF80236

[0201] 52 the system light, (ii) the color rendering index of the system light, and (iii) the correlated color temperature of the system light by controlling the movement element.

[0202] The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and / or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

[0203] The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0204] Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. 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. 2024PF80236

[0205] 53

[0206] The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “operational mode may also be indicated as “controlling mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and / or after executing the mode one or more other modes may be executed.

[0207] However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, which can only operate in a single operation mode (i.e. “on”, without further tunability).

[0208] Hence, in embodiments, 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.

[0209] 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, automotive applications, (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.

[0210] The terms “visible”, “visible light” or “visible emission” and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. Herein, UV may especially refer to a wavelength selected from the range of 190-380 nm, such as 200-380 nm. Herein, 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 up to about 1500 nm, like a wavelength of at least 900 nm, though in specific embodiments other wavelengths may also be possible. 2024PF80236

[0211] 54

[0212] 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. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

[0213] As indicated above, the light generating system comprises a light generating device. A light generating device may especially be configured to generate device light. Especially, the light generating device may comprise a light source. The light source may especially configured to generate light source light. In embodiments, the device light may essentially consist of the device light. In other embodiments, the device light may essentially consist of converted light source light. In yet other embodiments, the device light may comprise (unconverted) light source light and converted light source light. Light source light may be converted with a luminescent material into luminescent material light and / or with an upconverter into upconverted light. The term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions.

[0214] In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs.

[0215] Further, the term “light source” may in embodiments also refer to a so-called chips-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 source may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module. 2024PF80236

[0216] 55

[0217] The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die 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. 0.2-2 mm.

[0218] The light source may have a light escape surface. For LED’s it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the resin. In principle, it may also be the terminal end of a fiber. 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. Likewise, a light generating device may comprise a light escape surface, such as an end window. Further, likewise a light generating system may comprise a light escape surface, such as an end window. A position where system light escapes from the light generating system may also be indicated as light exit. This may be a light transmissive window or an opening (in the system). The light transmissive window may in embodiments be provided by an optical component.

[0219] The term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (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 a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, such as an LED, 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 an LED with on-chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering).

[0220] In embodiments, the 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, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, 2024PF80236

[0221] 56 which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs.

[0222] In other embodiments, however, the light source may be configured to provide primary radiation and part of the primary radiation is converted into secondary radiation. Secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be indicated as luminescent material radiation. The luminescent material may in embodiments be comprised by the light source, such as an LED with a luminescent material layer or dome comprising luminescent material. Such LEDs may be indicated as phosphor converted LEDs or PC LEDs (phosphor converted LEDs). In other embodiments, the luminescent material may be configured at some distance (“remote”) from the light source, such as an LED with a luminescent material layer not in physical contact with a die of the LED. Hence, in specific embodiments the light source may be a light source that during operation emits at least light at wavelength selected from the range of 380-470 nm. However, other wavelengths may also be possible. This light may partially be used by the luminescent material.

[0223] In embodiments, the light generating device may comprise a luminescent material. In embodiments, the light generating device may comprise a PC LED. In other embodiments, the light generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device may comprise a laser device, like a laser diode. In embodiments, the light generating device may comprise a superluminescent diode. Hence, 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.

[0224] 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, e.g. having band widths as known for lasers. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device).

[0225] The term “light source” herein may also refer to a light source comprising a solid state light source, such as an LED or a laser diode or a superluminescent diode.

[0226] The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources 2024PF80236

[0227] 57 selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin. The term “solid state light source”, or “solid state material light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a diode laser, or a superluminescent diode.

[0228] 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 spectral wavelength range of 200-2000 nm, such as 300-1500 nm. The term “laser” especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. Especially, in embodiments the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, refer to a laser diode (or diode laser).

[0229] 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 cerium doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium doped chrysoberyl (alexandrite) laser, chromium ZnSe (CrZnSe) laser, divalent samarium doped calcium fluoride (Sm:CaF2) laser, Er:YAG laser, erbium doped and erbium-ytterbium codoped glass lasers, F-Center laser, holmium YAG (Ho: YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium doped yttrium calcium oxoborate Nd:YCa4O(BO3)3 or Nd:YCOB, neodymium doped yttrium orthovanadate (Nd:YVO4) laser, neodymium glass (Nd:glass) laser, neodymium YLF (Nd:YLF) solid-state laser, promethium 147 doped phosphate glass (147Pm3+:glass) solid-state laser, ruby laser (AhO3:Cr3+), thulium YAG (Tm:YAG) laser, titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser, trival ent uranium doped calcium fluoride (U:CaF2) solid-state laser, Ytterbium doped glass laser (rod, plate / chip, and fiber), Ytterbium YAG (Yb:YAG) laser, Yb2O3 (glass or ceramics) laser, etc.

[0230] For instance, including second and third harmonic generation embodiments, the light source may comprise one or more of an F center laser, an yttrium orthovanadate (Nd:YVO4) laser, a promethium 147 doped phosphate glass (147Pm3+:glass), and a titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser. For instance, considering second and third harmonic generation, such light sources may be used to generated blue light. 2024PF80236

[0231] 58

[0232] 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.

[0233] A laser may be combined with an upconverter in order to arrive at shorter (laser) wavelengths. For instance, with some (trivalent) rare earth ions upconversion may be obtained or with non-linear crystals upconversion can be obtained. Alternatively, a laser can be combined with a downconverter, such as a dye laser, to arrive at longer (laser) wavelengths.

[0234] As can be derived from the below, 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, or more. In specific embodiments, N may be at least 5, such as especially at least 8. In this way, a higher brightness may be obtained. In embodiments, laser light sources may be arranged in a laser bank (see also above). The laser bank may in embodiments 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.

[0235] The laser light source is 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. In specific embodiments, the light source light is thus especially collimated light source light. In yet further embodiments, the light source light is especially (collimated) laser light source light.

[0236] The laser light source light may in embodiments comprise one or more bands, having band widths as known for lasers. In specific embodiments, the band(s) may be relatively sharp line(s), such as having full width half maximum (FWHM) in the range of less than 20 nm at RT, such as equal to or less than 10 nm. Hence, the light source light has a spectral power distribution (intensity on an energy scale as function of the wavelength) which may comprise one or more (narrow) bands. 2024PF80236

[0237] 59

[0238] 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. This small spot may be at the discrete converter region, or (slightly) upstream thereof or (slightly) downstream thereof. Especially, focusing and / or collimation may be such that the cross-sectional shape (perpendicular to the optical axis) of the beam at the discrete converter region (at the side face) is essentially not larger than the cross-section shape (perpendicular to the optical axis) of the discrete converter region (where the light source light irradiates the discrete converter region). Focusing may be executed with one or more optics, like (focusing) lenses. Especially, two lenses may be applied to focus the laser light source light. Collimation may be executed with one or more (other) optics, like 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). Hence, <2° (FWHM) may be considered (highly) collimated light source light. Optics may be used to provide (high) collimation (see also above).

[0239] The term “solid state material laser”, and similar terms, may refer to a solid state laser like based on a crystalline or glass body doped with ions, like transition metal ions and / or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, such as e.g. a vertical cavity surface-emitting laser (VCSEL), etc.

[0240] The term “solid state light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode. Instead of the term “solid state light source” also the term “semiconductor-based light source” may be applied. Hence, the term “semiconductor-based light source” may e.g. refer to one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.

[0241] A light-emitting diode (LED) is especially a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor may recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) may be determined by the energy required for electrons to cross the band gap of the semiconductor.

[0242] A laser diode (or diode laser) may be a semiconductor device substantially similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. This is known to a person skilled in the art. 2024PF80236

[0243] 60

[0244] Superluminescent diodes are known in the art. A superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like an LED, while having a brightness in the order of a laser diode.

[0245] 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. 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. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection 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 projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, a vehicle light, an automotive lighting device, a stage lighting device, a spot light, and an optical wireless communication 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. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the first light generating device, the first luminescent material, the diffuser assembly, the optical elements, and the light exit.

[0246] Instead of the terms “lighting device” or “lighting system”, and similar terms, also the terms “light generating device” or “light generating system”, (and similar terms), may be applied. A lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”). As indicated above, the terms light and radiation may interchangeably be used.

[0247] The lighting device may comprise a light source. The device light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).

[0248] The lighting system may comprise a light source. The system light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light). 2024PF80236

[0249] 61

[0250] BRIEF DESCRIPTION OF THE DRAWINGS

[0251] 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:

[0252] Figs. 1-5 schematically depict some embodiments of the light generating system.

[0253] Fig. 6 schematically depicts some applications of the light generating system in lighting devices.

[0254] The schematic drawings are not necessarily to scale.

[0255] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0256] Fig. 1 schematically depicts basic embodiments of the light generating system 1000 comprising a first light generating device 110, a first luminescent material 210, a diffuser assembly 700, optical elements 500, and a light exit 1090. Especially, in embodiments, the light generating system 1000 may comprise a first arrangement 1100 comprising the first light generating device 110, the first luminescent material 210, the (first) diffuser assembly 700, and optical elements 500.

[0257] In embodiments, the first light generating device 110 may be configured to generate first device light 111. Therefore, in embodiments, the first light generating device

[0258] 110 may comprise a first solid-state light source 10 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0259] The first luminescent material 210 may be configured in a light-receiving relationship with the first light generating device 110 (optionally via optical elements 500, such as a dichroic filter 502, see also further below). In embodiments, the first luminescent material 210 may be configured in the transmissive mode. Hence, in embodiments, the first luminescent material 210 may be configured to convert at least part of the first device light

[0260] 111 received by the first luminescent material 210 into first luminescent material light 211. Especially, in embodiments, the first luminescent material 210 may be configured to (i) convert at least 60% of the first device light 111 received by the first luminescent material 210 into first luminescent material light 211. Furthermore, in embodiments, the first luminescent material 210 may be configured to transmit at least part of the first device light 111 received by the first luminescent material 210 in an optical path to the diffuser assembly 700. Especially, in embodiments, the first luminescent material 210 may be configured to (scatter and) transmit at least 5% of the first device light 111 received by the first luminescent 2024PF80236

[0261] 62 material 210 (as unconverted first device light 111) in an optical path to the reflective polarizer 501.

[0262] Further, in embodiments, the first device light 111 may have a first centroid wavelength (Xci). Similarly, in embodiments, the first luminescent material light 211 may have a first luminescent material centroid wavelength (XCLMI). In embodiments, |Xci- CLMI|>10 nm. In further embodiments, the optical elements 500 may further comprise a dichroic filter 502 configured in an optical path between the first light generating device 110 and the first luminescent material 210. Especially, the dichroic filter 502 may be configured to (i) transmit the first device light 111 and (ii) reflect the first luminescent material light 211.

[0263] Hence, in embodiments, the optical elements 500 may comprise a reflective polarizer 501 configured in an optical path between the first luminescent material 210 and the diffuser assembly 700. In embodiments, the reflective polarizer 501 may be configured to reflect ( first device light 111 received by the reflective polarizer 501 and having a first linear polarization, and) first luminescent material light 211 received by the reflective polarizer 501 and having the first linear polarization back to the first luminescent material 210. Additionally, in embodiments, the reflective polarizer 501 may be configured to transmit (i) first device light 111 received by the reflective polarizer 501 and having a second linear polarization, and (ii) first luminescent material light 211 received by the reflective polarizer 501 and having the second linear polarization in an optical path to the diffuser assembly 700. In embodiments, the first linear polarization and the second linear polarization may be different, especially may be perpendicular (or complementary) to each other. Note that, in embodiments (as depicted in Fig. 1) the reflective polarizer 501 may be configured (in an optical path) between the first luminescent material 210 and a lens 560. Alternatively, in embodiments (not depicted), the reflective polarizer 501 may be configured (in an optical path) between the lens 560 and the first redirection optical element 510.

[0264] In embodiments, the diffuser assembly 700 may be configured to receive at least part of the first device light 111 and at least part of the first luminescent material light 211. The diffuser assembly 700 may especially comprise a diffuser 710 and a polarization converter 720. In embodiments, the diffuser 710 may comprise a polarization maintaining diffuser. In further embodiments (as depicted here), the diffuser 710 may be configured in the reflective mode. In embodiments, the diffuser 710 may be configured to diffuse the first device light 111 and the luminescent material light 201 received by the diffuser 710 into diffused first device light 711 and diffused (first) luminescent material light 271, respectively. 2024PF80236

[0265] 63

[0266] Further, in embodiments, the polarization converter 720 may be configured in an optical path between the reflective polarizer 501 and the diffuser 710. Especially, the polarization converter 720 may be configured (a) to convert linear polarized light received by the polarization converter 720 into elliptical polarized light and (b) to convert elliptical polarized light received by the polarization converter 720 into linear polarized light.

[0267] The optical elements 500 may further comprise a first polarization based redirection optical element 510. In embodiments, the first polarization based redirection optical element 510 may be configured in an optical path between the reflective polarizer 501 and the (reflective) diffuser assembly 700. In specific embodiments, the first polarization based redirection optical element 510 may comprise a polarizing beam splitter (PBS) or a reflective polarizer. The first polarization based redirection optical element 510 may especially be configured to direct (i) the luminescent material light 201 received by the first polarization based redirection optical element 510 and having the second linear polarization and (ii) (unconverted) first device light 111 received by the first polarization based redirection optical element 510 and having the second linear polarization in an optical path to the diffuser assembly 700. Especially, in embodiments, such as depicted here, the polarizing beam splitter (PBS) or the reflective polarizer may be configured: to transmit (i) first device light 111 211 received by the first polarization based redirection optical element 510 and having the second linear polarization and (ii) first luminescent material light 211 received by the first polarization based redirection optical element 510 and having the second linear polarization. Furthermore, in such embodiments, the polarizing beam splitter (PBS) or the reflective polarizer may be configured to reflect (i) diffused first device light 711 and having the first linear polarization and (ii) diffused luminescent material light 271 received by the first polarization based redirection optical element 510 and having the first linear polarization in an optical path to the light exit 1090.

[0268] Hence additionally, in embodiments, the first redirection optical element 510 may be configured to direct (i) diffused first device light 711 received by the first polarization based redirection optical element 510 and having the first linear polarization and (ii) diffused luminescent material light 271 received by the first polarization based redirection optical element 510 and having the first linear polarization in an optical path to the light exit 1090. Moreover, in embodiments (not depicted), the first redirection optical element 510 may be configured to reflect (i) first device light 111 received by the first polarization based redirection optical element 510 and having the second linear polarization and (ii) first luminescent material light 211 received by the first polarization based redirection optical 2024PF80236

[0269] 64 element 510 and having the second linear polarization. Additionally, in such embodiments, the polarizing beam splitter (PBS) or the reflective polarizer may be configured to transmit, (i) diffused first device light 711 received by the first polarization based redirection optical element 510 and having the first linear polarization and (ii) diffused luminescent material light 271 received by the first polarization based redirection optical element 510 having the first linear polarization in an optical path to the light exit 1090.

[0270] The light generating system 1000 may be configured to generate system light 1001. In embodiments, the system light 1001, in an operational mode of the light generating system 1000, may thus comprise at least part of the diffused luminescent material light 271 and at least part of the diffused first device light 711. Especially, in embodiments, the system light 1001 may be white light having a correlated color temperature selected from the range of 2000-12000 K and a color rendering index of at least 65. However, in alternative embodiments, the system light 1001 may be essentially any color.

[0271] Furthermore, in embodiments, the light generating system 1000 may be configured such that at least 80% of the first device light 111 reaching the first luminescent material 210 may have the second linear polarization.

[0272] Further, in embodiments, the light generating system 1000 may comprise a control system 300. In embodiments, the control system 300 may be configured to control one or more of (i) the color point of the system light 1001, (ii) the color rendering index of the system light 1001, and (iii) the correlated color temperature of the system light 1001 by controlling the light generating devices 110,120,. .. . Additionally, in embodiments, the light generating system 1000 may further comprise a movement element 310. In embodiments, the movement element 310 may be configured to rotate the reflective polarizer 501 (about its optical axis). As such, in embodiments, the control system 300 may be configured to control one or more of (i) the color point of the system light 1001, (ii) the color rendering index of the system light 1001, and (iii) the correlated color temperature of the system light 1001 by controlling the movement element 310.

[0273] Fig. 2 schematically depicts a further embodiment of the light generating system 1000. As depicted here, in embodiments, the light generating system 1000 may comprise a second subarrangement 1020 comprising a second light generating device 120, a second polarization based redirection optical element 520, and a second diffuser assembly 2700.

[0274] In embodiments, the second light generating device 120 may be configured to generate second device light 121. Especially, the second light generating device 120 may 2024PF80236

[0275] 65 comprise a second solid-state light source 20 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0276] Further, in embodiments, the second diffuser assembly 2700 may comprise a second diffuser 2710 and a second polarization converter 2720. Especially, the second diffuser 2710 may comprise a polarization maintaining diffuser. Moreover, in embodiments as depicted here, the second diffuser 2710 may be configured in the reflective mode. The second diffuser 2710 may especially be configured to diffuse the second device light 121 received by the second diffuser 2710 into diffused second device light 721. In embodiments, the second polarization converter 2720 may be configured in an optical path between the second polarization based redirection optical element 520 and the second diffuser 2710. The second polarization converter 2720 may especially be configured to convert linear polarized light received by the second polarization converter 2720 into elliptical polarized light. Additionally, in embodiments, the second polarization converter 2720 may be configured to convert elliptical polarized light received by the second polarization converter 2720 into linear polarized light.

[0277] In embodiments, the second polarization based redirection optical element 520 may be configured in a light-receiving relationship with the second light generating device 120. As such, in embodiments, the second polarization based redirection optical element 520 may be configured to direct second device light 121 received by the second polarization based redirection optical element 520 and having the first linear polarization in an optical path to the second diffuser assembly 2700. Additionally, in embodiments, the second polarization based redirection optical element 520 may be configured to direct diffused second device light 721 received by the second polarization based redirection optical element 520 and having the second linear polarization in an optical path to the light exit 1090.

[0278] Hence, in embodiments as depicted in Fig. 2, the system light 1001 in an operational mode of the light generating system 1000 may further comprise at least part of the diffused second device light 721.

[0279] In embodiments, the diffused first device light 711, the diffused luminescent material light 211, and the diffused second device light 721 may be combined into the same optical path to the light exit 1090 by an optical element 500. In some embodiments, the optical elements 500 may therefore comprise additional beam combining optics (such as e.g. a geometric beam combiner or a semitransparent mirror). In specific embodiments, the second redirection optical element 520 may be configured in a light-receiving relationship with both the second light generating device 120 and the first redirection optical element 510. 2024PF80236

[0280] 66

[0281] As such, in embodiments (such as depicted here), the second polarization based redirection optical element 520 may be configured to transmit (i) diffused first device light 711 received by the second polarization based redirection optical element 520 and having the first linear polarization and (i) diffused luminescent material light 271 received by the second polarization based redirection optical element 520 and having the first linear polarization in an optical path to the light exit 1090. Additionally, in such embodiments, the second polarization based redirection optical element 520 may be configured to reflect diffused second device light 721 received by the second polarization based redirection optical element 520 and having the second linear polarization in an optical path to the light exit 1090.

[0282] Alternatively, in embodiments (not depicted), the second polarization based redirection optical element 520 may be configured to reflect (i) diffused first device light 711 received by the second polarization based redirection optical element 520 and having the first linear polarization and (ii) diffused luminescent material light 271 received by the second polarization based redirection optical element 520 and having the first linear polarization in an optical path to the light exit 1090. Additionally, in such embodiments, the second polarization based redirection optical element 520 may be configured to transmit diffused second device light 721 received by the second polarization based redirection optical element 520 and having the second linear polarization in an optical path to the light exit 1090.

[0283] Fig. 3 schematically depicts a further embodiment of the light generating system 1000. As depicted here, in embodiments, the light generating system 1000 may further comprise a third subarrangement 1030 comprising a third light generating device 130, a third polarization based redirection optical element 530, and a third diffuser assembly 3700.

[0284] In embodiments, the third light generating device 130 may be configured to generate third device light 131. Especially, the third light generating device 130 may comprise a third solid-state light source 30 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0285] Further, in embodiments, the third diffuser assembly 3700 may comprise a third diffuser 3710 and a third polarization converter 3720. Especially, the third diffuser 3710 may comprise a polarization maintaining diffuser. Moreover, in embodiments as depicted here, the third diffuser 3710 may be configured in the reflective mode. The third diffuser 3710 may especially be configured to diffuse the third device light 131 received by the third diffuser 3710 into diffused third device light 731. In embodiments, the third polarization converter 3720 may be configured in an optical path between the third polarization based redirection optical element 530 and the third diffuser 3710. The third polarization converter 2024PF80236

[0286] 67

[0287] 3720 may especially be configured to convert linear polarized light received by the second polarization converter 3720 into elliptical polarized light. Additionally, in embodiments, the second polarization converter 3720 may be configured to convert elliptical polarized light received by the second polarization converter 3720 into linear polarized light.

[0288] In embodiments, the third polarization based redirection optical element 530 may be configured in a light-receiving relationship with the third light generating device 130. As such, in embodiments, the third polarization based redirection optical element 530 may be configured to direct third device light 131 received by the third polarization based redirection optical element 530 and having one of the first linear polarization and the second linear polarization in an optical path to the third diffuser assembly 3700. Additionally, in embodiments, the third polarization based redirection optical element 530 may be configured to direct diffused third device light 731 received by the third polarization based redirection optical element 530 and having the other one of the first linear polarization and the second linear polarization in an optical path to the light exit 1090.

[0289] Hence, in embodiments as depicted in Fig. 3, the system light 1001 in an operational mode of the light generating system 1000 may further comprise at least part of the diffused third device light 731. In embodiments, the third device light 131 (and thus the diffused third device light 731) may have a third peak wavelength ( ps).

[0290] The diffused first device light 711, the diffused luminescent material light 271, the diffused second device light 721, and the diffused third device light 731 may be combined in a plurality of different ways using the optical elements 500. As depicted in Fig. 3 A, in embodiments, the third polarization based redirection optical element 530 may comprise (one or more of) a partially polarizing beam splitter or a narrow-band polarizing beam splitter having polarization based splitting functionality for the third peak wavelength ( ps). Especially, in embodiments, the narrow-band polarizing beam splitter may be configured to transmit diffused first device light 711, diffused luminescent material light 271, and diffused second device light 721 independently of their respective polarizations.

[0291] Moreover, in embodiments, the partially polarizing beam splitter may be configured in a light-receiving relationship with the third light generating device 130, the third diffuser assembly 3700, and the second polarization based redirection optical element 520. Moreover, in embodiments (not depicted), the partially polarizing beam splitter may be configured to transmit (i) at least part of the diffused second device light 721 received by the partially polarizing beam splitter and having the second linear polarization, (ii) at least part of the third device light 131 received by the partially polarizing beam splitter and having the 2024PF80236

[0292] 68 second linear polarization, (iii) at least part of the diffused first device light 711 received by the partially polarizing beam splitter and having the first linear polarization, (iv) and diffused luminescent material light 271 received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit 1090. Additionally, in such embodiments, the partially polarizing beam splitter may be configured to reflect at least part of the diffused third device light 731 received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit 1090.

[0293] Alternatively, in embodiments (as depicted in Fig. 3 A), the partially polarizing beam splitter may be configured to transmit (i) at least part of the diffused first device light 711 received by the partially polarizing beam splitter and having the first linear polarization, (ii) at least part of the diffused luminescent material light 271 received by the partially polarizing beam splitter and having the first linear polarization, (iii) at least part of the third device light 131 received by the partially polarizing beam splitter and having the first linear polarization, and (iv) at least part of the diffused second device light 721 received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit 1090. Additionally, in such embodiments, the partially polarizing beam splitter may be configured to reflect at least part of the diffused third device light 731 received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit 1090.

[0294] Alternatively, as depicted in Fig. 3B, the optical elements 500 may comprise a fourth dichroic based redirection optical element 540 configured downstream of (all of) the first polarization based redirection optical element 510, the second polarization based redirection optical element 520, and the third polarization based redirection optical element 530. Especially, the fourth dichroic based redirection optical element 540 may be configured to direct (all of) the diffused first device light 711, the diffused luminescent material light 271, the diffused second device light 721, and the diffused third device light 731 received by the fourth dichroic based redirection optical element 540 into the same optical path to the light exit 1090.

[0295] As depicted in Fig. 4, in embodiments, the light generating system 1000 may further comprise a second arrangement 1200. Especially, in embodiments, the second arrangement 1200 may comprise the second subarrangement 1020, a second luminescent material 220 and a second reflective polarizer 521.

[0296] The second luminescent material 220 may be configured in a light-receiving relationship with the second light generating device 120. Further, in embodiments, the second 2024PF80236

[0297] 69 luminescent material 220 may be configured in the transmissive mode. Moreover, in embodiments, the second luminescent material 220 may be configured to convert at least part of the second device light 121 received by the second luminescent material 220 into second luminescent material light 221. Additionally, in embodiments, the second luminescent material 220 may be configured to transmit at least part of the second device light 121 received by the second luminescent material 220 in an optical path to the second diffuser assembly 2700.

[0298] In embodiments, the second diffuser 2710 may be further configured to diffuse the second luminescent material light 221 received by the second diffuser 2710 into diffused second luminescent material light 2271.

[0299] The second reflective polarizer 521 may especially be configured in an optical path between the second luminescent material 220 and the second diffuser assembly 2700. In embodiments, the second polarizer 521 may be configured to reflect (i) second device light 121 received by the second reflective polarizer 521 and having the second linear polarization and (ii) second luminescent material light 221 received by the second reflective polarizer 521 and having the second linear polarization back to the second luminescent material 220. Additionally, in embodiments, the second polarizer 521 may be configured to transmit (i) second device light 121 received by the second reflective polarizer 521 and having the first linear polarization and (ii) second luminescent material light 221 received by the second reflective polarizer 521 and having the first linear polarization in an optical path to the second diffuser assembly 2700.

[0300] Moreover, in embodiments, the second polarization based redirection optical element 520 may be further configured to direct the second luminescent material light 221 received by the second polarization based redirection optical element 520 and having the first linear polarization in an optical path to the diffuser assembly 2700. Additionally, in embodiments, the second polarization based redirection optical element 520 may be configured to direct the diffused second luminescent material light 2271 received by the second polarization based redirection optical element 520 and having the second linear polarization in an optical path to the light exit 1090. Hence, the system light 1001 may in an operational mode of the light generating system 1000 further comprise at least part of the diffused second luminescent material light 2271.

[0301] In embodiments, the first device light 111 may have a first centroid wavelength (Xci). Further, in embodiments as depicted in Fig. 5, the light generating system 1000 may comprise a fourth light generating device 140 and a fifth dichroic-based redirection 2024PF80236

[0302] 70 optical element 550. Especially, the fourth light generating device 140 may be configured to generate fourth device light 141 having a fourth centroid wavelength (Xc4). Moreover, in embodiments, |Xci-Xc4|>10 nm. Moreover, in embodiments, the fourth light generating device 140 may comprise a fourth solid-state light source 40 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0303] The fifth dichroic-based redirection optical element 550 may, in embodiments, be configured in a light-receiving relationship with the first light generating device 110 and the fourth light generating device 140 (especially may be configured to receive the first device light 111 and the fourth device light 141 from orthogonal directions). Especially, in embodiments, the fifth dichroic-based redirection optical element 550 may be configured to direct both the first device light 111 and the fourth device light 141 received by the fifth dichroic-based redirection optical element 550 in an optical path to the first luminescent material 210. Moreover, in embodiments, the first luminescent material 210 may be configured to transmit at least part of the fourth device light 141 received by the first luminescent material 210 (in an optical path to the diffuser assembly 700).

[0304] In further embodiments, the reflective polarizer 501 may be configured to transmit fourth device light 141 received by the reflective polarizer 501 and having the second linear polarization in an optical path to the diffuser assembly 700. Especially, the diffuser 710 may be configured to diffuse the fourth device light 141 received by the diffuser 710 into diffused fourth device light 741.

[0305] Furthermore, in embodiments, the first polarization based redirection optical element 510 may be configured to direct (as depicted here transmit, or alternatively reflect (not depicted)) the (unconverted) fourth device light 141 having the second linear polarization received by the first polarization based redirection optical element 510 in an optical path to the diffuser assembly 700. Additionally, in embodiments, the first polarization based redirection optical element 510 may be configured to direct (as depicted here reflect, or alternatively transmit (not depicted)) diffused fourth device light 741 having the first linear polarization received by the first polarization based redirection optical element 510 in an optical path to the light exit 1090. Hence, in embodiments, the system light 1001 in an operational mode of the light generating system 1000 may further comprise at least part of the diffused fourth device light 741.

[0306] Fig. 6 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 comprised by or functionally 2024PF80236

[0307] 71 coupled to the light generating system 1000. Fig. 6 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 6 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a vehicle light, an automotive lighting device, a stage lighting device, a spot light, or an optical wireless communication device. 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, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor, reference 1310 to a ceiling, and reference 1307 to a wall.

[0308] 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 opposed 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. 2024PF80236

[0309] 72

[0310] 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.

[0311] 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.

[0312] 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.

[0313] 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

2024PF8023673CLAIMS:

1. A light generating system (1000) comprising a first light generating device(110), a first luminescent material (210), a diffuser assembly (700), optical elements (500), and a light exit (1090), wherein; the first light generating device (110) is configured to generate first device light (111), wherein the first light generating device (110) comprises a first solid-state light source (10) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; the first luminescent material (210) is configured in a light-receiving relationship with the first light generating device (110); wherein the first luminescent material (210) is configured in the transmissive mode; wherein the first luminescent material (210) is configured to convert at least part of the first device light (111) received by the first luminescent material (210) into first luminescent material light (211); wherein the first luminescent material (210) is configured to transmit at least part of the first device light (111) received by the first luminescent material (210) in an optical path to the diffuser assembly (700); the optical elements (500) comprise a reflective polarizer (501) configured in an optical path between the first luminescent material (210) and the diffuser assembly (700); wherein the reflective polarizer (501) is configured (i) to reflect first luminescent material light (211) received by the reflective polarizer (501) and having a first linear polarization back to the first luminescent material (210), and (ii) to transmit (iia) first device light (111) received by the reflective polarizer (501) and having a second linear polarization, and (iib) to transmit first luminescent material light (211) received by the reflective polarizer (501) and having the second linear polarization in an optical path to the diffuser assembly (700); wherein the first linear polarization and the second linear polarization are different; the diffuser assembly (700) comprises a diffuser (710) and a polarization converter (720); wherein the diffuser (710) comprises a polarization maintaining diffuser, wherein the diffuser (710) is configured in the reflective mode; wherein the diffuser (710) is configured to diffuse the first device light (111) and the luminescent material light (201) received by the diffuser (710) into diffused first device light (711) and diffused luminescent2024PF8023674 material light (271); wherein the polarization converter (720) is configured in an optical path between the reflective polarizer (501) and the diffuser (710); wherein the polarization converter (720) is configured (a) to convert linear polarized light received by the polarization converter (720) into elliptical polarized light and (b) to convert elliptical polarized light received by the polarization converter (720) into linear polarized light; the optical elements (500) further comprise a first polarization based redirection optical element (510); wherein the first polarization based redirection optical element (510) is configured in an optical path between the reflective polarizer (501) and the diffuser assembly (700); wherein the first polarization based redirection optical element (510) is configured to (i) direct (ia) the luminescent material light (201) received by the first polarization based redirection optical element (510) and having the second linear polarization and (ib) first device light (111) received by the first polarization based redirection optical element (510) and having the second linear polarization in an optical path to the diffuser assembly (700), and to (ii) direct (iia) diffused first device light (711) received by the first polarization based redirection optical element (510) and having the first linear polarization and (iib) diffused luminescent material light (271) received by the first polarization based redirection optical element (510) and having the first linear polarization in an optical path to the light exit (1090); and the light generating system (1000) is configured to generate system light (1001), wherein the system light (1001), in an operational mode of the light generating system (1000), comprises at least part of the diffused luminescent material light (271) and at least part of the diffused first device light (711).

2. The light generating system (1000) according to claim 1, wherein the first polarization based redirection optical element (510) comprises a polarizing beam splitter (PBS) or a reflective polarizer; wherein the polarizing beam splitter (PBS) or the reflective polarizer is configured: to (i) transmit (ia) first device light (111) received by the first polarization based redirection optical element (510) and having the second linear polarization and (ib) first luminescent material light (211) received by the first polarization based redirection optical element (510) and having the second linear polarization, and to (ii) reflect (iia) diffused first device light (711) received by the first polarization based redirection optical element (510) and having the first linear polarization and (iib) diffused luminescent material2024PF8023675 light (271) received by the first polarization based redirection optical element (510) and having the first linear polarization; or to (i) reflect (ia) first device light (111) received by the first polarization based redirection optical element (510) and having the second linear polarization and (ib) first luminescent material light (211) received by the first polarization based redirection optical element (510) and having the second linear polarization, and to (ii) transmit (iia) diffused first device light (711) received by the first polarization based redirection optical element (510) and having the first linear polarization and (iib) diffused luminescent material light (271) received by the first polarization based redirection optical element (510) and having the first linear polarization.

3. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) is configured such that at least 80% of the first device light (111) reaching the first luminescent material (210) has the second linear polarization.

4. The light generating system (1000) according to any one of the preceding claims, wherein the first luminescent material (210) is configured to (i) convert at least 60% of the first device light (111) received by the first luminescent material (210) into first luminescent material light (211), and (ii) transmit at least 5% of the first device light (111) received by the first luminescent material (210) in an optical path to the reflective polarizer (501).

5. The light generating system (1000) according to any one of the preceding claims, wherein the first device light (111) has a first centroid wavelength (Xci), wherein the first luminescent material light (211) has a first luminescent material centroid wavelength (XCLMI), and wherein |XCI-XCLMI|>10 nm; wherein the optical elements (500) further comprise a dichroic filter (502) configured in an optical path between the first light generating device (110) and the first luminescent material (210), wherein the dichroic filter (502) is configured to (i) transmit the first device light (111) and (ii) reflect the first luminescent material light2024PF80236766. The light generating system (1000) according to any one of the preceding claims, further comprising a second light generating device (120), a second polarization based redirection optical element (520), and a second diffuser assembly (2700), wherein: the second light generating device (120) is configured to generate second device light (121), wherein the second light generating device (120) comprises a second solid-state light source (20) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; the second diffuser assembly (2700) comprises a second diffuser (2710) and a second polarization converter (2720); wherein the second diffuser (2710) comprises a polarization maintaining diffuser, wherein the second diffuser (2710) is configured in the reflective mode; wherein the second diffuser (2710) is configured to diffuse the second device light (121) received by the second diffuser (2710) into diffused second device light (721); wherein the second polarization converter (2720) is configured in an optical path between the second polarization based redirection optical element (520) and the second diffuser (2710); wherein the second polarization converter (2720) is configured to convert linear polarized light received by the second polarization converter (2720) into elliptical polarized light and to convert elliptical polarized light received by the second polarization converter (2720) into linear polarized light; the second polarization based redirection optical element (520) is configured in a light-receiving relationship with the second light generating device (120); wherein the second polarization based redirection optical element (520) is configured to (i) direct (ia) second device light (121) received by the second polarization based redirection optical element (520) and having the first linear polarization in an optical path to the second diffuser assembly (2700), and to (ii) direct (iia) diffused second device light (721) received by the second polarization based redirection optical element (520) and having the second linear polarization in an optical path to the light exit (1090); and the system light (1001) in an operational mode of the light generating system (1000) further comprises at least part of the diffused second device light (721).

7. The light generating system (1000) according to claim 6, wherein the second redirection optical element (520) is configured in a light-receiving relationship with both the second light generating device (120) and the first redirection optical element (510); wherein the second polarization based redirection optical element (520) is configured:2024PF8023677 to (i) transmit (ia) diffused first device light (711) received by the second polarization based redirection optical element (520) and having the first linear polarization and (ib) diffused luminescent material light (271) received by the second polarization based redirection optical element (520) and having the first linear polarization in an optical path to the light exit (1090), and (ii) reflect diffused second device light (721) received by the second polarization based redirection optical element (520) and having the second linear polarization in an optical path to the light exit (1090); or to (i) reflect (ia) diffused first device light (711) received by the second polarization based redirection optical element (520) and having the first linear polarization and (ib) diffused luminescent material light (271) received by the second polarization based redirection optical element (520) and having the first linear polarization in an optical path to the light exit (1090), and (ii) transmit diffused second device light (721) received by the second polarization based redirection optical element (520) and having the second linear polarization in an optical path to the light exit (1090).

8. The light generating system (1000) according to any one of the preceding claims, further comprising a third light generating device (130), a third polarization based redirection optical element (530), and a third diffuser assembly (3700), wherein: the third light generating device (130) is configured to generate third device light (131), wherein the third light generating device (130) comprises a third solid-state light source (30) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; the third diffuser assembly (3700) comprises a third diffuser (3710) and a third polarization converter (3720); wherein the third diffuser (3710) comprises a polarization maintaining diffuser, wherein the third diffuser (3710) is configured in the reflective mode; wherein the third diffuser (3710) is configured to diffuse the third device light (131) received by the third diffuser (3710) into diffused third device light (731); wherein the third polarization converter (3720) is configured in an optical path between the third redirection optical element (530) and the third diffuser (3710); wherein the third polarization converter (3720) is configured to convert linear polarized light received by the third polarization converter (3720) into elliptical polarized light and to convert elliptical polarized light received by the third polarization converter (3720) into linear polarized light; the third polarization based redirection optical element (530) is configured in a light-receiving relationship with the third light generating device (130); wherein the third2024PF8023678 polarization based redirection optical element (530) is configured to (i) direct the third device light (131) received by the third polarization based redirection optical element (530) and having one of the first linear polarization and the second linear polarization in an optical path to the third diffuser assembly (3700), and to (ii) direct diffused third device light (731) received by the third redirection optical element (530) and having the other one of the first linear polarization and the second linear polarization in an optical path to the light exit (1090); and the system light (1001) in an operational mode of the light generating system (1000) further comprises at least part of the diffused third device light (731).

9. The light generating system (1000) according to claim 8, wherein one of the following applies: the third polarization based redirection optical element (530) comprises a partially polarizing beam splitter, wherein the partially polarizing beam splitter is configured in a light-receiving relationship with the third light generating device (130), the third diffuser assembly (3700), and the second polarization based redirection optical element (520); wherein the partially polarizing beam splitter is configured to:- (i) transmit (ia) at least part of the diffused second device light (721) received by the partially polarizing beam splitter and having the second linear polarization, (ib) at least part of the third device light (131) received by the partially polarizing beam splitter and having the second linear polarization, (ic) at least part of the diffused first device light (711) received by the partially polarizing beam splitter and having the first linear polarization, (id) and diffused luminescent material light (271) received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit (1090), and to (ii) reflect at least part of the diffused third device light (731) received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit (1090); or- (i) transmit (ia) at least part of the diffused first device light (711) received by the partially polarizing beam splitter and having the first linear polarization, (ib) at least part of the diffused luminescent material light (271) received by the partially polarizing beam splitter and having the first linear polarization, (ic) at least part of the third device light (131) received by the partially polarizing beam splitter and having the first linear polarization, and (id) at least part of the diffused second device light (721) received by the partially polarizing beam splitter and having the second linear polarization in an optical path to the light exit2024PF8023679(1090), and to (ii) reflect at least part of the diffused third device light (731) received by the partially polarizing beam splitter and having the first linear polarization in an optical path to the light exit (1090); the third device light (131) has a third peak wavelength ( ps), wherein the third redirection optical element (530) comprises a narrow-band polarizing beam splitter having polarization based splitting functionality for the third peak wavelength ( ps); or the optical elements (500) comprise a fourth dichroic based redirection optical element (540) configured downstream of the first polarization based redirection optical element (510), the second polarization based redirection optical element (520), and the third polarization based redirection optical element (530); wherein the fourth dichroic based redirection optical element (540) is configured to direct the diffused first device light (711), the diffused luminescent material light (271), the diffused second device light (721), and the diffused third device light (731) received by the fourth dichroic based redirection optical element (540) into the same optical path to the light exit (1090).

10. The light generating system (1000) according to any one of the preceding claims, wherein the first device light (111) has a first centroid wavelength (Xci), wherein the light generating system (1000) further comprises a fourth light generating device (140) and a fifth dichroic-based redirection optical element (550), wherein: the fourth light generating device (140) is configured to generate fourth device light (141) having a fourth centroid wavelength (Xc4), wherein |Xc i -Xc4|>l 0 nm; wherein the fourth light generating device (140) comprises a fourth solid-state light source (40) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; the fifth dichroic-based redirection optical element (550) is configured in a light-receiving relationship with the first light generating device (110) and the fourth light generating device (140); wherein the fifth dichroic-based redirection optical element (550) is configured to (i) direct both the first device light (111) and the fourth device light (141) received by the fifth dichroic-based redirection optical element (550) in an optical path to the first luminescent material (210); the first luminescent material (210) is configured to transmit at least part of the fourth device light (141) received by the first luminescent material (210);2024PF8023680 the reflective polarizer (501) is configured to transmit fourth device light (141) received by the reflective polarizer (501) and having the second linear polarization in an optical path to the diffuser assembly (700); the diffuser (710) is configured to diffuse the fourth device light (141) received by the diffuser (710) into diffused fourth device light (741); the first polarization based redirection optical element (510) is configured to (i) direct the fourth device light (141) received by the first polarization based redirection optical element (510) and having the second linear polarization in an optical path to the diffuser assembly (700), and to (ii) direct diffused fourth device light (741) received by the first polarization based redirection optical element (510) and having the first linear polarization in an optical path to the light exit (1090); the system light (1001) in an operational mode of the light generating system (1000) further comprises at least part of the diffused fourth device light (741).

11. The light generating system (1000) according to any one of the preceding claims, further comprising a control system (300), wherein one or more of the following applies: the control system (300) is configured to control one or more of (i) the color point of the system light (1001), (ii) the color rendering index of the system light (1001), and (iii) the correlated color temperature of the system light (1001) by controlling the light generating devices (110,120,....); and the light generating system (1000) further comprises a movement element (310) configured to rotate the reflective polarizer (501), and wherein the control system (300) is configured to control one or more of (i) the color point of the system light (1001), (ii) the color rendering index of the system light (1001), and (iii) the correlated color temperature of the system light (1001) by controlling the movement element (310).

12. The light generating system (1000) according to any one of the preceding claims 6-12, further comprising a second luminescent material (220) and a second reflective polarizer (521), wherein: the second luminescent material (220) is configured in a light-receiving relationship with the second light generating device (120); wherein the second luminescent material (220) is configured in the transmissive mode; wherein the second luminescent material (220) is configured to convert at least part of the second device light (121) received2024PF8023681 by the second luminescent material (220) into second luminescent material light (221); and wherein the second luminescent material (220) is configured to transmit at least part of the second device light (121) received by the second luminescent material (220) in an optical path to the second diffuser assembly (2700); the second diffuser (2710) is further configured to diffuse the second luminescent material light (221) received by the second diffuser (2710) into diffused second luminescent material light (2271); the second reflective polarizer (521) is configured in an optical path between the second luminescent material (220) and the second diffuser assembly (2700), wherein the second polarizer (521) is configured (i) to reflect (ia) second device light (121) received by the second reflective polarizer (521) and having the second linear polarization and (ib) second luminescent material light (221) received by the second reflective polarizer (521) and having the second linear polarization back to the second luminescent material (220), (ii) to transmit (iia) second device light (121) received by the second reflective polarizer (521) and having the first linear polarization and (iib) second luminescent material light (221) received by the second reflective polarizer (521) and having the first linear polarization in an optical path to the second diffuser assembly (2700); the second polarization based redirection optical element (520) is further configured to (i) direct the second luminescent material light (221) received by the second polarization based redirection optical element (520) and having the first linear polarization in an optical path to the diffuser assembly (2700), and to (ii) direct the diffused second luminescent material light (2271) received by the second polarization based redirection optical element (520) and having the second linear polarization in an optical path to the light exit (1090); and the system light (1001) in an operational mode of the light generating system (1000) further comprises at least part of the diffused second luminescent material light (2271).

13. The light generating system (1000) according to any one of the preceding claims, wherein the first luminescent material (210) at least comprises a luminescent material of the type AsBsO 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 generating devices (100,110,120,130,140...) each comprise a laser bank comprising a plurality of diode lasers.2024PF802368214. The light generating system (1000) according to any one of the preceding claims, wherein in an operational mode of the light generating system (1000): the first device light (111) has a wavelength selected from the wavelength range of 430-490 nm; and the system light (1001) is white light having a correlated color temperature selected from the range of 2000-12000 K and a color rendering index of at least 65.

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

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