Eye-safe high-brightness luminescent converter pumped by diffused laser light

Abstract

The invention provides a light generating system (1000) comprising a first light generating device (110), a luminescent material (200), 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 optical elements (500) comprise a first redirection optical element (1510) configured in a light-receiving relationship with the first light generating device (110); wherein the first redirection optical element (1510) is configured to (i) direct the first device light (111) in an optical path to the diffuser assembly (700), and to (ii) direct at least part of diffused device light (711) in an optical path to the luminescent material (200) (C) the diffuser assembly (700) comprises (a) a diffuser (710), 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 at least part of the first device light (111) received by the diffuser (710) into diffused device light (711), wherein the diffused device light (711) has a full width half maximum of at least 5°; and (b) a quarter waveplate (720); wherein the light generating system (1000) is configured such that first device light (111) reaching the quarter waveplate (720) comprises linearly polarized light; wherein the quarter waveplate (720) is configured to convert linear polarized light received by the quarter waveplate (720) into elliptical polarized light and to convert elliptical polarized light received by the quarter waveplate (720) into linear polarized light; wherein the diffuser assembly (700) is configured to provide the diffused device light (711) in an optical path to the luminescent material (200) via the first redirection optical element (1510); (D) the luminescent material (200) is configured to convert at least part of the diffused device light (711) received by the luminescent material (200) into luminescent material light (201); (E) the optical elements (500) are configured to direct at least part of the luminescent material light (201) in an optical path to the light exit (1090); and (F) the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) system light (1001) comprising at least part of the luminescent material light (201).

Description

[0001] Eye-safe high-brightness luminescent converter pumped by diffused laser light

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a light generating system. The invention further relates to a lighting device comprising the light generating system.

[0004] BACKGROUND OF THE INVENTION

[0005] Lighting fixtures with built-in eye-safety are known in the art.

[0006] US2019323803 Al, 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.

[0007] SUMMARY OF THE INVENTION

[0008] 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, such prior art systems may have relatively high risks for eye-safety should one or more optical components break or malfunction. Therefore, it may be desired to improve the safety, compactness and / or performance / cost ratio of laser-phosphor technology. 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.

[0009] According to a first aspect, the invention provides a light generating system (“system”) comprising a first light generating device, a 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. Therefore, in embodiments, 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 further embodiments, the optical elements may comprise one or more redirection optical elements. Especially, in embodiments, the (one or more redirection) optical elements may at least comprise a first redirection optical element. In embodiments, the first redirection optical element may be configured in a light-receiving relationship with the first light generating device. Furthermore, in embodiments, the first redirection optical element may be configured to direct the first device light in an optical path to the diffuser assembly. Additionally, in embodiments, the first redirection optical element may be configured to direct at least part of diffused device light in an optical path to the luminescent material. Moreover, in embodiments, the diffuser assembly may comprise a diffuser and a quarter waveplate. In embodiments, the diffuser may comprise a polarization maintaining diffuser. Moreover, in embodiments, the diffuser may be configured in the reflective mode. Especially, the diffuser may be configured to diffuse at least part of the first device light received by the diffuser into diffused device light. In embodiments, the diffused device light may have a full width at half maximum (FWHM) of at least 5°. The quarter waveplate may, in embodiments, be configured in an optical path between the first redirection optical element and the diffuser. Further, in embodiments, the light generating system may be configured such that first device light reaching the quarter waveplate may comprise linear polarized light. In embodiments, the quarter waveplate may be configured to convert linear polarized light received by the quarter waveplate into elliptical polarized light and to convert elliptical polarized light received by the quarter waveplate into linear polarized light. Furthermore, in embodiments, the diffuser assembly may be configured to provide the diffused device light in an optical path to the luminescent material via the first redirection optical element. Subsequently, in embodiments, the luminescent material may be configured to convert at least part of the diffused device light received by the luminescent material into luminescent material light. Therefore, in embodiments, the optical elements may be configured to direct at least part of the luminescent material light in an optical path to the light exit. Hence, in embodiments, the light generating system may be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the luminescent material light. Hence, in embodiments, the invention provides a light generating system comprising a first light generating device, a luminescent material, a diffuser assembly, optical elements, and a light exit, wherein; (A) the first light generating device may be configured to generate first device light, wherein 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; (B) the optical elements may comprise one or more redirection optical elements at least comprising a first redirection optical element; wherein the first redirection optical element may be configured in a lightreceiving relationship with the first light generating device; wherein the first redirection optical element may be configured to (i) direct the first device light in an optical path to the diffuser assembly, and to (ii) direct at least part of diffused device light in an optical path to the luminescent material; (C) the diffuser assembly may comprise (a) a diffuser, wherein the diffuser may comprise a polarization maintaining diffuser, wherein the diffuser may be configured in the reflective mode; wherein the diffuser may be configured to diffuse at least part of the first device light received by the diffuser into diffused device light, wherein the diffused device light may have a full width half maximum (FWHM) of at least 5°; and (b) a quarter waveplate, wherein the quarter waveplate may be configured in an optical path between the first redirection optical element and the diffuser; wherein the light generating system may be configured such that first device light reaching the quarter waveplate may comprise linearly polarized light; wherein the quarter waveplate may be configured to convert linear polarized light received by the quarter waveplate into elliptical polarized light and to convert elliptical polarized light received by the quarter waveplate into linear polarized light; wherein the diffuser assembly may be configured to provide the diffused device light in an optical path to the luminescent material via the first redirection optical element; (D) the luminescent material may be configured to convert at least part of the diffused device light received by the luminescent material into luminescent material light; (E) the optical elements may be configured to direct at least part of the luminescent material light in an optical path to the light exit; and (F) the light generating system may be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the luminescent material light. Such a light generating system may provide high-brightness laser-phosphor based light. The system may especially provide facile variation in color, while also enabling configurations for providing high-brightness white light. Furthermore, the light generating system may be relatively compact as a limited number of components are required. As a result, the system may further be relatively cost-efficient. Yet further, the light generating system of the invention may be relatively eye-safe in case of break or malfunction of components. Hence, the invention may provide an eye-safe high-brightness luminescent converter pumped by diffused laser light.

[0010] The light generating system (or “system”) may thus comprise a light generating device, a luminescent material, a diffuser assembly, optical elements, and a light exit. Here below, embodiments of the different elements of the light generating system will be described in further detail.

[0011] The light generating devices may be configured to generate device light. Therefore, in embodiments, the light generating device may comprise a solid-state light source. In embodiments, the light generating system may comprise (at least) a 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). In specific embodiments, the first light generating device may comprise at least two first solid-state light sources, such as e.g. two lasers. 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 light emitting arrangement comprising) 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 a 2D array, such as 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. 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 expander. Depending on the desired output beam characteristics, additional beam shaping optics may be needed. Hence, in embodiments, the first light generating device may comprise a first laser bank, wherein the first laser bank may comprise a light emitting arrangement comprising a 2D array of a plurality of first laser diodes arranged on a thermally conductive carrier and a lens array having a plurality of collimator lenses corresponding to the first laser diodes such that each laser diode of the plurality of first laser diodes may comprise a collimator lens for collimating laser light emitted by the laser diode.

[0012] Further, in embodiments, the first light generating device may especially be configured to generate first device light having a first centroid wavelength (Xci). In embodiments, the first centroid wavelength (Xci) may be essentially any wavelength. Especially, in embodiments, the first device light may have a first centroid wavelength (Xci) selected from the visible wavelength range. Hence, the first device light may have essentially any color. In specific 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, for instance from the range of 420-490 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, 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 nm. Especially, in embodiments the device light has a centroid wavelength selected from the blue wavelength range. However, in alternative embodiments, the first device light may have a first centroid wavelength (Xci) selected from for example the yellow or red wavelength range, see also further below. Hence, in embodiments, the first device light may comprise essentially any color, and may even be white light, see also further below.

[0013] In some embodiments, the light generating system may comprise further light generating devices, such as e.g. a second light generating device. Such embodiments may be beneficial as higher intensity system light may be obtained. Above described embodiments for the first light generating device may, in embodiments, also apply for such further light generating devices. For example, in embodiments, the light generating system may comprise the first light generating device and a second light generating device, which may be essentially the same type of light generating device (e.g. a laser from the same bin). Alternatively, in embodiments, the first light generating device and the second light generating device may be different. For example, in embodiments, the first light generating device may have the first centroid wavelength (Xci) selected from the wavelength range of 440-490 nm (i.e. may comprise blue light), whereas the second light generating device may have a second centroid wavelength (Xc2) selected from the wavelength range of 620-780 nm (i.e., may comprise red light).

[0014] Furthermore, in embodiments, the first light generating device and the second light generating device may be spatially separated, e.g. separate laser banks. Alternatively, in embodiments, the first light generating device and the second light generating device may be combined in the same laser bank. 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.

[0015] In embodiments, the first light generating device may especially be configured to provide first device light to the optical elements. In embodiments, the optical elements may comprise one or more 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.

[0016] In particular, in embodiments, the optical elements (especially the redirection optical elements) may comprise at least a first redirection optical element. Herein, in embodiments, a redirection optical element may have one or more of a beam combining functionality and a beam splitting functionality (see also further below). Hence, herein instead of the term “redirection optical element” also the term “beam splitter” or “beam combiner” may be applied. The fact that the optical elements may comprise a first redirection optical element does not exclude the presence of other optical elements, and may also include the use of one or more further redirection optical elements (see also below).

[0017] In specific embodiments, the first light generating device may especially be configured to provide first device light to the first redirection optical element. 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. The first redirection optical element may thus be configured downstream of 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”.

[0018] In embodiments, the first device light may be polarized light or a polarization may be imposed to the first device light, e.g. with a polarizer. Hence, the first device light reaching the first polarizing beam splitter may comprise polarized light. In specific embodiments, the laser light may comprise linear polarized light. 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%. In embodiments where the laser light comprises some (e.g. at most 10%, such as at most 5%, like at most 1%) oscillations occurring outside the single plane, the laser light may be partially polarized light comprising linear polarized light.

[0019] 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., desired 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 (or orthogonal polarizations). The first redirection optical element may, in embodiments, be configured to direct first device light received by the first redirection optical element (in dependence of its linear polarization) in an optical path to the diffuser assembly.

[0020] In embodiments, the diffuser assembly may comprise a polarization converter and a diffuser. In embodiments, the diffuser may especially be configured in the reflective mode. Especially, the diffuser may be configured such that an optical axis of incoming first device light and an optical axis of outgoing diffused device light (relative to the diffuser) may have a parallel direction relative to each other. Herein, the term “optical axis” (O) may be defined as an imaginary line that defines the path along which light propagates towards or from a respective element. For example, the optical axis of the first device light incident on the diffuser may be defined as an imaginary line that defines the path along which light propagates (from the first light generating device) to the diffuser. More especially, the optical axis (O) may coincide with the direction of the light with the highest radiant flux. Examples and embodiments of the diffuser are described further below.

[0021] For the polarization converter may apply that, in embodiments, the polarization converter may comprise a birefringent rotator, more especially a / 4 waveplate (or quarter waveplate). Especially, in embodiments, the (diffuser assembly may comprise a) quarter waveplate configured in an optical path between the first redirection optical element and the diffuser. As known from the art, a waveplate or retarder is an optical device that alters the polarization state of a light wave travelling through it. 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 (first) device light received by the quarter waveplate into elliptical (such as especially circularly) polarized (first) device light. Additionally or alternatively, in embodiments, the quarter waveplate may be configured to convert elliptical polarized (diffused) device light (such as especially circularly) 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 first redirection optical element and the diffuser. As such, the first redirection optical element may thus be configured to direct (first) device light received by the first redirection optical element and comprising (either) the first linear polarization or the second linear polarization (optionally via optics) to the polarization converter (i.e. the quarter waveplate). The quarter waveplate may, in embodiments, be configured to convert (first) device light received by the quarter waveplate comprising a linear polarization into (first) device light having a (first) circular polarization. At the diffuser, in embodiments, the (first) device light having the (first) circular polarization may be diffused into (first) diffused device light having a second circular polarization. Therefore, in embodiments, the quarter waveplate may also be configured to convert (first) diffused device light received by the quarter waveplate (via the diffuser) and having the (second) circular polarization into (first) diffused device light comprising a linear polarization. For example, in embodiments, p-polarized first device light may be directed by the first redirection optical element to the quarter waveplate. In such embodiments, the quarter waveplate may be configured to convert the p-polarized first device light into left-handed circularly polarized first device light. Further, in such embodiments, the diffuser assembly may be configured to diffuse the left-handed circularly polarized first device light received by the diffuser into right-handed circularly polarized diffused device light. The quarter waveplate may then, in embodiments, be configured to convert the right-handed circularly polarized diffused device light received by the quarter waveplate (back) to linear polarized light, especially to s-polarized diffused device 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 device light. Hence, in embodiments, the diffuser assembly may comprise an arrangement of a polarization converter and a diffuser.

[0022] The diffuser may thus, in embodiments, be configured to diffuse at least part of the device light received by the diffuser system into diffused device light. Especially, in embodiments, the diffuser may be configured to diffuse at least 30%, like at least 50%, such as at least 60%, like at least 70% of the device light, received by the diffuser, into diffused device light. Especially, in embodiments, the diffuser may be configured to diffuse at least 80%, more especially at least 90%, including 100% of the device light received by the diffuser into diffused device light. In embodiments, the diffuser may especially comprise a substantially polarization maintaining diffuser, i.e., the diffuser may be configured to substantially maintain the polarization of the incident light upon diffusion (and in some embodiments reflection)(even though the handedness may (thus) change). Such embodiments may be beneficial as depolarization at the diffuser may be reduced, therewith improving the efficiency of the contribution of the diffuser arrangement to the system light. Therefore, in embodiments, the diffuser may comprise a metal coated surface textured glass substrate mounted on a heat conductive material such as e.g. a metal or a ceramic. In such embodiments, the heat conductive material may be configured to conduct away heat that may be generated in the diffuser due to some absorption of incident device light.

[0023] Further, in embodiments, the diffuser may be configured to diffuse the (first) device light, such that the diffused device light may have a full width at half maximum (FWHM) selected from the range of 5-60°. Especially, in embodiments, the diffused device light may have a FWHM of at least 2°, such as at least 3°, like at least 5°, especially at least 10°. Further, in embodiments, the diffused device light may have a FWHM of at least 15°, such as at least 20°. Yet, in embodiments, the diffused device light may have a FWHM of at most 70°, such as at most 60°, like at most 30°, especially at most 20°. Furthermore, in embodiments, the diffused device light may have a FWHM of at most 45°, such as at most 35°. Hence, in embodiments, the diffused device light has a FWHM selected from the range of 5-60°, such as selected from the range of 15-40°. In other words, the (first) diffuser may have a diffusion angle selected from the range of 5-60°. In embodiments, the term “diffusion angle” may refer to the (relatively smooth) broadening of an incident beam of radiation that may be characterized by the full width at half maximum of the diffused radiant angular intensity distribution for an incident (non-diffused) pencil beam (i.e., an incident beam of radiation with a negligible angular extent (FWHM) compared to the FWHM of the diffused beam). In further embodiments, the first diffuser may have a diffusion angle of at minimum 1°, such as at least about 1.5° (the diffusion angle of a specular reflector may thus be 0°), such as at least about 2°, but at maximum about 30°, like selected from the range of about 2- 30°, more especially selected from the range of 5-30°.

[0024] Herein, the full width half maximum especially refers to a beam angle, defined by the full width half maximum. Hence, “the phrase FWHM of at least 5°”, and similar phrases, may refer to a beam having a beam angle of at least 5° (or at least 2*2.5°), wherein the beam (angle) is defined by the full width half maximum of the beam. The angular width or angular extent of e.g. at least 5°, may indicate a beam divergence.

[0025] In embodiments, the diffuser may thus be configured to diffuse the first device light received by the diffuser. Furthermore, in embodiments, the diffuser assembly may be configured to provide the diffused device light in an optical path to the luminescent material via the first redirection optical element. Hence, in embodiments, the first redirection optical element may further be configured to direct at least part of the diffused device light in an optical path to the luminescent material.

[0026] In embodiments, the luminescent material may thus be configured (optionally via one or more further (optical) elements) in a light-receiving relationship with the first redirection optical element. In other words, the luminescent material may, in such embodiments, be configured downstream of (both the diffuser (assembly) and) the first redirection optical element. In embodiments, the luminescent material may be configured to convert at least part of the diffused device light received by the luminescent material into luminescent material light.

[0027] 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.

[0028] 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 (Xex>Xem).

[0029] 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 “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.

[0030] 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.

[0031] 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 AsBsOnT'e. 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%.

[0032] 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.

[0033] Hence, in specific embodiments the luminescent material comprises a luminescent material of the type AsBsOnT'e. 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 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)3BsOi2: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)3AlsOi2:Ce, part ofY 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.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0034] In specific embodiments the luminescent material comprises (Yxi-x2- x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y 2=1, wherein 0<y2<0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially xl>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions.

[0035] In specific embodiments at maximum 10% of B-0 may be replaced by Si-N. Here, B in B-0 refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in specific embodiments B-0 may refer to Al-O. As indicated above, in specific embodiments x3 may be selected from the range of 0.001-0.04. Especially, such luminescent materials may have a suitable spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (optionally in combination with (the) light of other sources of light as described herein). Hence, in specific embodiments A may be selected from the group consisting of Lu and Gd. Alternatively or additionally, B may comprise Ga. Hence, in embodiments the luminescent material comprises (Yxi-x2- x3(Lu,Gd)x2Cex3)3(Alyi-y2Gay2)5Oi2, wherein Lu and / or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3<0.1, and wherein 0<y2<0.1. Further, in specific embodiments, at maximum 1% of B-0 may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yxi-x3Cex3)3A150i2, wherein xl+x3=l, and wherein 0<x3<0.2, such as 0.001-0.1.

[0036] Alternatively or additionally, the luminescent material may comprise a luminescent material of the type AsSieNi i:Ce3. wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.

[0037] In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+and / or I LSisNsYu2and / or MAISiN.vEu2and / 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 CaAlSiN3: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.

[0038] In embodiments, the luminescent material may comprise a luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises 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".

[0039] 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’xNfc- 2xAXe luminescent material has the hexagonal phase. In yet another embodiment, the M’xNfc- 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.5Sro.25AX6 might be applied. As indicated above, x may be in the range of 0-1, especially x<l. In an embodiment, x=0.

[0040] 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 tetraval ent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12.

[0041] In an embodiment, M’xM2-2xAX6 comprises K2SiFe (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 silicon is replaced by manganese (i.e. the formula may also be described as K2Sii-mMnmF6 or KRbSii-mMnmFe, 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)2SiF6: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.

[0042] Hence, when M refers to n different elements, this may imply that the relevant formula may comprise for the M position in the formula essentially any permutation of the n different elements. For instance, when M=Ba,Sr,Ca or when M comprises one or more of Ba,Sr,Ca or when M refers to Ba,Sr,Ca, this may imply that in the formula Ba, Sr, Ca, (BaxSry), (BaxCay), (CaxSry), or (BaxSryCaz), may be available, wherein in general x+y+z=l. Referring to e.g. M’xM2-2xAX6, this may refer to e.g. one or more of K2SiFe:Mn4+and of Rb2SiFe:Mn4+, or (KxRby)2SiF6:Mn4+, etc. Further, indications like “K,Rb” or Ba,Sr,Ca, and similar indications (see also above), may indicate one or more of such elements. Hence, (K,Rb)2SiFe:Mn4+, may e.g. refer to K2SiFe:Mn4+and of Rb2SiFe:Mn4+, or (KxRby)2SiF6:Mn4+. Also herein in general x+y=l. Hence, when M may refer to n different elements, with n being at least two, 2n-l permutations may in principle be possible.

[0043] 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.

[0044] 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.

[0045] The term “luminescent material” herein especially relates to inorganic luminescent materials.

[0046] Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc.. Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used. Instead of quantum dots or in addition to quantum dots, also other quantum confinement structures may be used. 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.

[0047] In general, the luminescent material may give rise to quite a lot of thermal dissipation. Therefore, in embodiments, this 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. In specific embodiments, the luminescent material may be configured in the reflective mode. In the reflective mode, thermal management may be easier, as a substantial part of the luminescent material may be in thermal contact with a thermally conductive element, like a heatsink or heat spreader.

[0048] Hence, in embodiments, the luminescent material may thus be configured in the reflective mode. In alternative embodiments, the 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. 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 average distance between two respective surfaces of the respective elements. 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).

[0049] 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.

[0050] 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 oxide, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, diamond, and graphite. 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 (and may e.g. transfer heat to) one or more of a heatsink, a heat spreader, and a two- phase cooling device.

[0051] Hence, in embodiments, the luminescent material may be configured in the transmissive mode. In other words, the luminescent material may comprise a transmissive luminescent converter. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, especially at least 70% of the diffused device light received by the luminescent material into luminescent material light. More especially, in embodiments, the luminescent material may be configured to convert at least 80%, such as at least 90%, especially at least 95% of the diffused device light received by the luminescent material into luminescent material light. Moreover, in embodiments, the luminescent material may be configured to convert at least 90%, like at least 98%, such as at least 99%, especially at least 99,5%, including 100% of the diffused device light received by the luminescent material into luminescent material light. Hence, in such embodiments, the luminescent material may be configured in a full- conversion mode. In such embodiments, the luminescent material may further be configured to transmit less than 5%, such as less than 2%, like less than 1,5%, especially less than 1%, including 0%, of the diffused device light received by the luminescent material as unconverted diffused device light. Hence, in embodiments, wherein the luminescent material may be configured in the transmissive mode, the luminescent material may be configured to convert at least 90% of the diffused device light received by the luminescent material into luminescent material light (and the luminescent material may further be configured to transmit less than 2% (or less than 1%, e.g. 0%) of the diffused device light received by the luminescent material).

[0052] The optical elements may then, in embodiments, be configured to direct at least part of the luminescent material light in an optical path to the light exit. Hence, in embodiments, the optical elements of the light generating system may be configured to provide at least luminescent material light to the light exit. In such embodiments, the light generating system may thus be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the luminescent material light. As the luminescent material may comprise any of the luminescent materials described above, in embodiments, the system light may comprise essentially any wavelength selected from the visible wavelength range. For example, in embodiments, the system light may comprise luminescent material light having a wavelength selected from the yellow-green wavelength range (e.g. the luminescent material may comprise a AsBsO^Ce type luminescent material). Hence, in such embodiments, the system light may be yellow-green light. In an alternative embodiment, the system light may comprise luminescent material light having a wavelength selected from the red wavelength range (e.g. the luminescent material may comprise a KSiF type luminescent material). Hence, in such embodiments, the system light may be red light.

[0053] Furthermore, in embodiments, the luminescent material may be configured to convert at most 100%, such as at most 99%, like at most 95%, especially at most 90% of the diffused device light received by the luminescent material into luminescent material light. Hence, in embodiments, the luminescent material may be configured to convert at least 60% of the diffused device light received by the luminescent material into luminescent material light. In specific embodiments, (wherein the luminescent material may be configured in the transmissive mode), the luminescent material may be configured to convert at least 60% of the diffused device light received by the luminescent material into luminescent material light.

[0054] Furthermore, in embodiments, the luminescent material may (also) be configured to transmit at least part of the diffused device light received by the luminescent material. Especially, in embodiments, the luminescent material may be further configured to transmit at least 3%, especially at least 5%, such as at least 10%, like at least 15% of the diffused device light received by the luminescent material (as unconverted diffused device light) in an optical path to the light exit. Moreover, in embodiments, the luminescent material may be further configured to transmit at most 40%, such as at most 30%, like at most 20% of the diffused device light received by the luminescent material (as unconverted diffused device light) in an optical path to the light exit. In such embodiments, the optical elements may further be configured to direct at least part of the diffused device light transmitted by the luminescent material in an optical path to the light exit. Therefore, in embodiments, the light generating system may be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the luminescent material light and at least part of the diffused device light (transmitted by the luminescent material).

[0055] In general, luminescent materials may suffer from slight efficiency reduction over time. To improve the overall efficiency of the luminescent conversion in the light generating system, the optical elements may further comprise a dichroic reflector and / or a reflective polarizer. Especially, in embodiments, the optical elements may comprise a dichroic reflector configured in an optical path between the first redirection optical element and the luminescent material. The dichroic reflector may especially be configured to transmit the (first) diffused device light (in an optical path to the luminescent material) and to reflect the luminescent material light (back to the luminescent material). The dichroic reflector may especially be configured to transmit or reflect light in dependence of its spectral power distribution. In specific embodiments, the dichroic reflector may be configured to transmit blue diffused device light (in an optical path to the luminescent material) and to reflect yellow-green (or even red) luminescent material light (back to the luminescent material).

[0056] Additionally or alternatively, in embodiments, the optical elements may comprise a reflective polarizer configured in an optical path between the first redirection optical element and the luminescent material. The reflective polarizer may especially be configured to transmit the (first) diffused device light (in an optical path to the luminescent material) and to reflect the luminescent material light (back to the luminescent material). The reflective polarizer may especially be configured to transmit or reflect light in dependence of its polarization. In specific embodiments, the reflective polarizer may be configured to transmit diffused device light having the first or second linear polarization (in an optical path to the luminescent material) and to reflect at least part (especially the part not having that same first or second linear polarization) of the unpolarized luminescent material light (back to the luminescent material). Hence, in embodiments, the optical elements may comprise one or more of a dichroic reflector and a reflective polarizer configured in an optical path between the first redirection optical element and the luminescent material, wherein the one or more of a dichroic reflector and a reflective polarizer may be configured to (i) transmit (first and / or) diffused device light and (ii) at least partly reflect luminescent material light.

[0057] Hence, in specific embodiments, diffused device light may be provided through operation of the diffuser in the reflective mode, while luminescent material light may be provided through operation of the luminescent material in the transmissive mode. Especially, in embodiments, the diffused device light may be reflected by the diffuser into an optical path to the luminescent material and the luminescent material may be configured to (i) convert at least part of the diffused device light into luminescent material, and to (ii) transmit at least part of the diffused device light. The optical elements may then, in embodiments, be configured to provide system light comprising the luminescent material light and the diffused device light to the light exit. Especially, in an operational mode of the light generating system, the light generating system may be configured to generate system light comprising at least part of the diffused device light and at least part of the luminescent material light. In specific embodiment, the system light may thus be white light.

[0058] 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. 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.

[0059] In specific embodiments, the correlated color temperature (CCT) may be 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 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 70. Especially, in embodiments, the correlated color temperature (CCT) may be selected from the range of 2000-12000 K, in combination with a CRI of at least 65, such as at least 70, like at least 75, especially at least 80.

[0060] In embodiments, in an operational mode of the light generating system, the system light may especially be white light having a correlated color temperature selected from the range of 2000-12000 K, such as selected from the range of 6000-10000 K, like selected from the range of 6500-8000K. Especially, in embodiments, in an operational mode of the light generating system, the system light may especially be white light having a correlated color temperature selected from the range of 2000-900K. Additionally or alternatively, in embodiments, in an operational mode of the light generating system, the system light may especially be white light having a color rendering index of at least 60, such as at least 65, like at least 70, especially at least 80, more especially at least 90. In specific embodiments, the system light 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. For example, in embodiments, in an operational mode of the light generating system, the system light may be white light having a correlated color temperature selected from the range of 2000-9000K and a color rendering index of at least 70.

[0061] As described above, in embodiments, the light generating system may comprise a second light generating device. In embodiments, the second light generating device may be configured to generate second device light. Therefore, the second light generating device may comprise a second solid-state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi-junction light-emitting diodes. Furthermore, in embodiments, the second light generating device may comprise a second laser bank. Especially, the second laser bank may comprise a light emitting arrangement comprising a 2D array of a plurality of second laser diodes arranged on a thermally conductive carrier and a lens array. Especially, in embodiments, the lens array may have a plurality of collimator lenses corresponding to the second laser diodes, such that each laser diode of the plurality of second laser diodes may comprise a collimator lens for collimating laser light emitted by the laser diode.

[0062] In embodiments, the first redirection optical element may (also) be configured in a light-receiving relationship with the second light generating device. Especially, in embodiments, (during operation of the light generating system) the first redirection optical element may be configured to direct the second device light in an optical path to the diffuser assembly. Additionally, in embodiments, (during operation of the light generating system) the first redirection optical element may be configured to direct at least part of diffused second device light in an optical path to the luminescent material. In embodiments, the second device light received by the first redirection optical element may comprise linear polarized light. In embodiments, the second device light may comprise the same linear polarization as the first device light, whereas diffused second device light may comprise the same linear polarization as the diffused device light. In such embodiments, the second device light may propagate through the light generating system in the same way as the first device light. Similarly, in such embodiments, the diffused second device light may propagate through the light generating system in the same way as the diffused (first) device light. Hence, the first device light and the second device light may be diffused (into diffused device light and diffused second device light, respectively) by the same (first) diffuser. For example, in such embodiments, the second device light may (also) have a wavelength selected from the wavelength range of at least 420 nm, such as selected from the range of 430-490 nm. Hence, in embodiments, the first device light and the second device light may be blue light. However, this may not necessarily be the case. In embodiments, the first device light and the second device light may have a wavelength individually selected from the visible wavelength range (i.e. 380-780 nm).

[0063] However, in alternative embodiments, the light generating system may further comprise a second diffuser assembly. The second diffuser assembly may, in embodiments, comprise a second diffuser and a second quarter waveplate. In embodiments, the second diffuser may comprise a polarization maintaining diffuser. Furthermore, in embodiments, the second diffuser may be configured in the reflective mode. Especially, in embodiments, the second diffuser may be configured to diffuse at least part of the second device light received by the second diffuser into diffused second device light. The diffused second device light may, in embodiments, have a full width half maximum (FWHM) of at least 5° (such as selected from the range of 5-60°). Furthermore, in embodiments, the second quarter waveplate may be configured in an optical path between the first redirection optical element and the second diffuser. The light generating system may especially be configured such that second device light reaching the second quarter waveplate may comprise linearly polarized light. The second quarter waveplate may then be configured to convert linear polarized light received by the second quarter waveplate into elliptical polarized light. Especially, in embodiments, the second quarter waveplate may be configured to provide elliptically polarized second device light to the second diffuser. Additionally, in embodiments, the second quarter waveplate may be configured to convert elliptical polarized (diffused second device) light received by the second quarter waveplate into linear polarized light. As such, in embodiments, the diffused second device light may propagate from the second diffuser via the second quarter waveplate back to the first polarizing beam splitter. Thus, in embodiments, the second diffuser assembly may be configured to provide the diffused second device light in an optical path to the luminescent material via the first redirection optical element.

[0064] In such embodiments, the first redirection optical element may be configured to (i) transmit first device light and diffused second device light comprising the first linear polarization and (ii) reflect diffused device light and second device light comprising the second linear polarization. Alternatively, in embodiments, the first redirection optical element may be configured to (i) reflect first device light and diffused second device light comprising the first linear polarization and (ii) transmit diffused device light and second device light comprising the second linear polarization. Especially, in embodiments, the first redirection optical element may be configured to provide second device light to the second diffuser assembly. Furthermore, in embodiments comprising the second light generating device, the luminescent material may (in an operational mode of the light generating system) be configured to convert at least part of the diffused second device light received by the luminescent material into luminescent material light. Especially, in embodiments, the luminescent material may be configured to convert at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the diffused second device light received by the luminescent material into luminescent material light. Further, in embodiments, the 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 diffused second device light received by the luminescent material into luminescent material light.

[0065] In embodiments, the optical elements may thus be configured to (help) propagate the different types of light through the light generating system. Especially, in embodiments, the first redirection optical element may be configured to direct the first device light in an optical path to the diffuser assembly. Additionally, in embodiments, the first redirection optical element may be configured to direct the diffused device light in an optical path to the luminescent material.

[0066] In embodiments, the (first) device light received by the first redirection optical element may especially be polarized light. Hence, in embodiments, the light generating system may be configured such that (both) the first device light and( / or) the diffused device received by the first redirection optical element may comprise polarized 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 e.g. a controlling mode (for instance whether or not a light generating device provides light).

[0067] In embodiments, the second linear polarization may especially be different from the first linear polarization. Especially, in embodiments, the second linear polarization may be (about) 90° rotated relative to the first linear polarization. More especially, in some embodiments the first linear polarization may be p-polarization and the second linear polarization may be s-polarization. In other embodiments, the first polarization may be s- polarization and the second polarization may be p-polarization. Herein, the terms “p- polarization” and “s-polarization” may especially refer to the polarization of light when incident on (a light-receiving plane of) the light-receiving element, such as e.g. the first polarization based redirection optics (especially the first polarizing beam splitter).

[0068] Hence, in embodiments the first device light and the diffused device light reaching the first (polarization based, see also further below,) redirection optical element may have essentially complementary polarizations. Hence, in embodiments the first device light reaching the first redirection optical element may essentially be p-polarized light and the diffused device light reaching the first redirection optical element may essentially be s- polarized light, or the first device light reaching the first redirection optical element may essentially be s-polarized light and the diffused device light reaching the first redirection optical element may essentially be p-polarized light. Therefore, the first redirection optical element may be polarization based. Hence, e.g. a beam of elliptically polarized light may be split in two (orthogonal) beams of s-polarized light and p-polarized light. For instance, one of the polarizations may be transmitted, and one of the polarizations may be reflected. This may also imply that a beam of light that consists of essentially linear polarized light may be (at least partly) reflected or (at least partly) transmitted at the polarization based redirection optics. Hence, the redirection optics may comprise a polarizing beam splitter. In other words, the first redirection optical element may also be referred to as a first polarizing beam splitter. Such optics, however, may also be used to combine a beam of light. Especially, e.g. a beam of s-polarized light and a beam of p-polarized light may be combined into a beam of light comprising both polarizations, i.e. light that can generally be described as elliptically polarized light (note that this may include the extremes of circular polarized light as well as linear polarized light). For instance, one of the beams may be transmitted, and one of the beams may be reflected. The combined beam may propagate in the same direction as one of the transmitted beam and reflected beam. Hence, the redirection optics may comprise a polarizing beam combiner. Such optics, however, may thus also be used to split beams of light. Hence, the herein described polarization based redirection optics are herein also indicated as polarization beam combiners, or polarizing beam combiners, or polarization beam splitters, or polarizing beam splitters, and are shortly indicated as “PBS”.

[0069] The first polarizing beam splitter may be used to split the first device light and diffused device light. Hence, this may imply that the first device light reaching the first polarizing beam splitter and the diffused device light reaching the first polarizing beam splitter have different polarizations. One may be s-polarized and the other one may be p- polarized. One may be elliptically polarized, and the other one may be s-polarized or p- polarized. Especially, however, the diffused device light and first device light differ in polarization, like s-polarized light and p-polarized light, or both elliptically polarized, but one comprising more s-polarization than p-polarization, and the other one comprising more p- polarization than s-polarization. For example, in embodiments, the first device light and the diffused device light may each comprise a linear polarization, wherein the linear polarizations of the first device light and the diffused device light may be about 90° rotated with respect to each other. In specific embodiments, one of the first device light and the diffused device light may comprise the first linear polarization and the other one of the first device light and the diffused device light may comprise the second linear polarization. In such embodiments, the first linear polarization and the second linear polarization may be about 90° rotated relative to each other, i.e., they may be (orthogonal or) complementary relative to each other.

[0070] Further, in embodiments the first device light reaching the first polarizing beam splitter and the diffused device light reaching the first polarizing beam splitter (having different polarizations) may be orthogonally incident on the first polarizing beam splitter. Especially, in embodiments the optical axes of the first device light reaching the first polarizing beam splitter and the diffused device light reaching the first polarizing beam splitter may both have angles of incidence of 45° (although other angles are herein not excluded). In embodiments, the angles of incidence of 45° may especially refer to angles of incidence of 45°±5°, more especially 45°±2°, such as 45°±1°.

[0071] Especially, in embodiments, the first redirection optical element (i.e. the first polarizing beam splitter) may be configured to transmit (or reflect) at least 60%, such as at least 70%, like at least 80% of the light (comprising the first linear polarization) received by the first polarizing beam splitter. Especially, in embodiments, the first polarizing beam splitter may be configured to transmit (or reflect) at least 90%, more especially at least 95%, including 100% of the light (comprising the first linear polarization) received by the first polarizing beam splitter. Especially, in embodiments, the first redirection optical element may be configured to transmit first device light comprising the first linear polarization. Alternatively, in embodiments, the first redirection optical element may be configured to reflect first device light comprising the first linear. Further, in such embodiments, the first polarizing beam splitter may be configured to reflect (or transmit) light received by the first polarizing beam splitter and (said (device) light) comprising a second linear polarization. Especially, in embodiments, the first polarizing beam splitter may be configured to reflect (or transmit) at least 60%, such as at least 70%, like at least 80% of the light (comprising the second linear polarization) received by the first polarizing beam splitter. Especially, in embodiments, the first polarizing beam splitter may be configured to reflect (or transmit) at least 90%, more especially at least 95%, including 100% of the light (comprising the second linear polarization) received by the first polarizing beam splitter. Especially, in embodiments, the first redirection optical element may be configured to reflect diffused device light comprising the second linear polarization, different from the first linear polarization. Alternatively, in embodiments, the first redirection optical element may be to transmit diffused device light comprising the second linear polarization, different from the first linear polarization. Note that, in embodiments, the first polarizing beam splitter may herein especially function as a beam splitter. Especially, in embodiments, the first polarizing beam splitter may be configured to split (into separate optical paths) the first device light and the diffused device light. Above percentages may refer to the percentage of the radiant flux (received by the first polarizing beam splitter (especially under 45° angle with a normal of the plane of incidence of the element)). Hence, in embodiments, a polarizing beam splitter may especially be configured to split light received by the polarizing beam splitter into orthogonal beams of light having different (complementary) polarization. The polarizing beam splitter may especially do so upon irradiation at an about 45° angle. Additionally or alternatively, in embodiments, a polarizing beam splitter may be configured to combine light received by the polarizing beam splitter from orthogonal beams of light and having different (complementary) (linear) polarizations into a same optical path.

[0072] Hence, in specific embodiments, the first redirection optical element may comprise a polarizing beam splitter, wherein the polarizing beam splitter may be configured (a) to transmit first device light comprising a first linear polarization and to reflect diffused device light comprising a second linear polarization, different from the first linear polarization, or (b) to reflect first device light comprising the first linear polarization and to transmit diffused device light comprising the second linear polarization, different from the first linear polarization.

[0073] As can be derived from the above, in embodiments, the first redirection optical element may be configured to direct first device light (received by the first redirection optical element) and diffused device light (received by the first redirection optical element) in different optical paths. Especially, in embodiments, the first redirection optical element may be configured to direct first device light (received by the first redirection optical element) into an optical path to the diffuser assembly and diffused device light (received by the first redirection optical element) in an optical path to the luminescent material. In embodiments, the one or more redirection optical elements may further comprise a second redirection optical element configured between the first redirection optical element and the luminescent material. The second redirection optical element may, in embodiments, comprise one or more of a geometry -based redirection optical element, a dichroic-based redirection optical element, and a neutral redirection optical element.

[0074] In embodiments, the second redirection optical element may comprise a geometry-based redirection optical element. In embodiments, a geometry-based redirection optical element may comprise a plate comprising geometric-optical features that may correlate to a geometrical distribution of light sources configured to provide light to the geometric beam combiner. As such, in embodiments, light from part of the light sources (configured to provide light to the GBC) may be reflected by the geometric beam combiner. In other words, light from part of the light sources (configured to provide light to the GBC) may be redirected (by the GBC) in a direction substantially different from the direction of the incident light. Conversely, in embodiments, light from another part of the light sources (configured to provide light to the GBC at a different location on the GBC than the previous part) may be transmitted by the geometric beam combiner. Therefore, in embodiments, at least part of the second redirection optical element may comprise a light transmissive, especially a light transparent, material. In other words, light from part of the light sources (configured to provide light to the GBC) may be directed (by the GBC) in a direction substantially equal to the direction of the incident light. Such reflection or transmission of the light may, in embodiments, depend on the geometric-optical design of the geometric beam combiner. Hence, in embodiments, a geometric beam combiner may provide geometric (or spatial) beam splitting functionality as it may split an incident device light source beam into two separate output beams, independent of their polarization and / or wavelength.

[0075] Further, in embodiments, the second redirection optical element may comprise a dichroic-based redirection optical element. In embodiments, via a dichroic-based redirection optical element, device light from a single optical path may be split provided that the spectral power distribution of the device light comprises at least two different peak wavelengths. For instance, in embodiments, the first light generating device may comprise a first subset of solid state light sources configured to provide device light having a first peak wavelength and a second subset of solid state light sources configured to provide device light having a second peak wavelength. In such embodiments, the device light having different peak wavelengths may be split with a dichroic-based redirection optical element (which may also be indicated as dichroic beam combiner or dichroic beam splitter). In another example, in embodiments, the light generating system may comprise a second light generating device (see also further below) configured to generate second device light which may propagate via the (first or second) diffuser assembly and the first redirection optical element to the second redirection optical element. Note that, in embodiments, the dichroic-based redirection optical element (e.g. dichroic mirror) may be configured to reflect essentially all of light received by the dichroic-based redirection optical element and having a certain wavelength range (i.e. above or below a cut-off wavelength). Alternatively, in embodiments, the dichroic-based redirection optical element (e.g. dichroic mirror) may be configured to reflect only a fraction of the light received by the dichroic-based redirection optical element and having a certain wavelength range (i.e. above or below a cut-off wavelength). Hence, in such embodiments, the dichroic-based redirection optical element

[0076] Yet further, in embodiments, the second redirection optical element may comprise a neutral redirection optical element. In embodiments, the neutral redirection optical element may be configured to transmit or reflect light received by the neutral redirection optical element in dependence of Fresnel reflection of the light received by the neutral redirection optical element, therewith resulting in (two) separate beams. In embodiments, the neutral redirection optical element may especially comprise one or more stacks of dielectric layers configured to tune the reflection properties without specific (or intended) spectral or polarization preferences. In embodiments, the neutral redirection optical element may (also) comprise a semi-reflecting mirror. For example, in such embodiments, the neutral redirection optical element may comprise a (thin) layer of e.g. aluminum configured on a substrate.

[0077] Yet alternatively, in embodiments, the second redirection optical element may comprise a reflective polarizer. In embodiments, the reflective polarizer may comprise a plate configured to transmit light having a predetermined (linear) polarization, whereas it may be configured to reflect (all) other polarizations. Such a reflective polarizer may especially be useful in embodiments where the first device light and / or second device light may not consist (solely) of linear polarized light, but may also comprise other polarizations (or even unpolarized light).

[0078] As described above, in embodiments, the optics (especially the first redirection optical element) may thus be configured to direct a part of the device light in an optical path to the luminescent material.

[0079] In some embodiments, the (first) diffuser assembly may be selected to provide diffused device light having a relatively small full width half maximum (FWHM), such as less than 30°. Such embodiments may be beneficial as a spot of diffused device light provided onto the luminescent material may remain relatively small, therewith improving the lifetime of the luminescent material. In such embodiments, the light generating system may further comprise a second diffuser assembly. Especially, in such embodiments, the optics may be configured to (i) direct a part of the (diffused) device light in an optical path to the luminescent material and (ii) direct another part of the (diffused) device light in an optical path to the second diffuser assembly.

[0080] Therefore, in embodiments, the second redirection optical element may be configured in a light-receiving relationship with the first redirection optical element. Moreover, in embodiments, the second redirection optical element may be configured in a light-receiving relationship with the (first) diffuser assembly via the first redirection optical element. Especially, in embodiments, the second redirection optical element may be configured to (i) direct a part of the (diffused) device light (received by the second redirection optical element from the first redirection optical element) in an optical path to the luminescent material and (ii) direct another part of the (diffused) device light (received by the second redirection optical element from the first redirection optical element) in an optical path to the second diffuser assembly. In specific embodiments, the second redirection optical element may be configured to direct part of the (diffused) device light (received by the second redirection optical element from the first redirection optical element) in an optical path to the second diffuser assembly while bypassing the luminescent material. Hence, in specific embodiments, the optical elements may comprise a second redirection optical element, wherein the second redirection optical element may be configured in a light receiving relationship with the diffuser via the first redirection optical element; wherein the second redirection optical element may be configured to (i) direct a first part of the diffused device light in an optical path to the luminescent material, and to (ii) direct a second part of the diffused device light in an optical path to the light exit while bypassing the luminescent material. In other words, in embodiments, at least a part of the (diffused) device light may not be provided in an optical path to (i.e. incident on) the luminescent material. Rather, in such embodiments, that part of the (diffused) device light may be provided in an optical path to (i.e. incident on) the second diffuser assembly.

[0081] In embodiments, the second diffuser assembly may comprise a second diffuser. In embodiments, the second diffuser may especially be configured in the transmissive mode. Especially, the second diffuser may be configured such that an optical axis of incoming diffused device light and an optical axis of outgoing secondary diffused device light (relative to the second diffuser) may have a parallel yet opposite direction relative to each other.

[0082] The second diffuser may, in embodiments, be configured to diffuse at least part of the (first) diffused device light received by the second diffuser assembly into secondary diffused device light. Especially, in embodiments, the second diffuser may be configured to diffuse at least 30%, like at least 50%, such as at least 60%, like at least 70% of the diffused device light, received by the second diffuser, into secondary diffused device light. Especially, in embodiments, the second diffuser may be configured to diffuse at least 80%, more especially at least 90%, including 100% of the diffused device light received by the second diffuser into secondary diffused device light.

[0083] Further, in embodiments, the second diffuser may be configured to diffuse the diffused device light, such that the secondary diffused device light may have a full width at half maximum (FWHM) selected from the range of 40-120°. Especially, in embodiments, the secondary diffused device light may have a FWHM of at least 15°, such as at least 20°, like at least 25°, especially at least 30°. Further, in embodiments, the secondary diffused device light may have a FWHM of at least 40°, such as at least 45°. In embodiments, the secondary diffused device light may have a FWHM larger than the FWHM of the first diffused device light. Especially, in embodiments, the secondary diffused device light may have a FWHM of at most 125°, such as at most 120°, like at most 110°, especially at most 100°. Yet, in embodiments, the secondary diffused device light may have a FWHM of at most 90°, such as at most 85°, like at most 80°, especially at most 75°. Furthermore, in embodiments, the secondary diffused device light may have a FWHM of at most 70°, such as at most 65°. Hence, in embodiments, the secondary diffused device light has a FWHM selected from the range of 40-120°, such as selected from the range of 40-60°. In other words, the second diffuser may have a diffusion angle selected from the range of 40-120°, such as e.g. from the range of 40-80°.

[0084] In embodiments, the second diffuser may thus be configured to diffuse the diffused device light received by the second diffuser. Furthermore, in embodiments, the second diffuser assembly may be configured to provide the secondary diffused device light in an optical path to the light exit. Therefore, in embodiments, optical elements may further comprise a third redirection optical element. In embodiments, the third redirection optical element may comprise a dichroic-based redirection optical element (i.e. a dichroic beam combiner). Especially, in embodiments, the third redirection optical element may be configured in a light received relationship with both the luminescent material and the second diffuser assembly. More especially, in embodiments, the third redirection optical element may be configured in an optical path between (i) the luminescent material and the light exit, and (ii) the second diffuser assembly and the light exit. In embodiments, the third redirection optical element may be configured to direct the luminescent material light and the secondary diffused device light received by the third redirection optical element in an optical path to the light exit. The third redirection optical element may thus combine the luminescent material light and the secondary diffused device light in dependence of their respective spectral power distributions.

[0085] Especially, in embodiments, the third redirection optical element may be configured to transmit the luminescent material light received by the third redirection optical element in an optical path to the light exit. Additionally, in such embodiments, the third redirection optical element may be configured to reflect the secondary diffused device light received by the third redirection optical element in an optical path to the light exit. Alternatively, in embodiments, the third redirection optical element may be configured to reflect the luminescent material light received by the third redirection optical element in an optical path to the light exit. Additionally, in such embodiments, the third redirection optical element may be configured to transmit the secondary diffused device light received by the third redirection optical element in an optical path to the light exit.

[0086] Hence, in embodiments, the light generating system may further comprise a second diffuser assembly, wherein the second diffuser assembly may comprise a second diffuser; wherein the second diffuser may be configured in an optical path between the second redirection optical element and the light exit; wherein the second diffuser may be configured to receive the second part of the diffused device light, wherein the second diffuser may be configured to diffuse at least part of the second part of the diffused device light received by the second diffuser into secondary diffused device light; wherein the second diffuser may be configured to provide the secondary diffused device light in an optical path to the light exit; wherein the light generating system may be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the luminescent material light and at least part of the secondary diffused device light. Such embodiments may be beneficial as the second diffuser assembly may allow for tailoring of the distribution of the secondary diffused device light to any desired distribution, such as e.g. a gaussian or a Lambertian distribution. Especially, such embodiments may enable tailoring of the secondary diffused device light, such that it may have a distribution matching the distribution of the luminescent material light. In embodiments, the (first and / or second) diffuser may comprise a static diffuser. Alternatively, in embodiments, the diffuser (first and / or second) may comprise a dynamic diffuser, such as e.g. a rotating wheel comprising a reflective diffuser track. Hence, in embodiments, the light generating system may comprise a rotating element. As described above, some components (such as the luminescent material and / or the diffuser(s)) may prone to the generation of heat. Such heat may be detrimental to the lifetime and efficiency of the light generating system. Therefore, in embodiments, the light generating system may comprise the rotating element. In embodiments, one or more of the luminescent material and the (first and / or second) diffuser may be configured on the rotating element. Especially, in embodiments, the (first) diffuser and the luminescent material may each be configured on a separate rotating element. Such a rotating element may e.g. comprise a rotating (phosphor) wheel or a rotating rod.

[0087] Furthermore, in embodiments, the light generating system may comprise optics configured such that the diffused device light and / or the luminescent material light may be provided to the light exit. The term “optics” may especially refer to (one or more) optical elements. Hence, the terms “optics” and “optical elements” may refer to the same items. The optics may include one or more of mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, arrays of one or more of the afore-mentioned, etc. Alternatively or additionally, the term “optics” may refer to a holographic element or a mixing rod. In embodiments, the optics may include one or more of beam expander optics and zoom lens optics. See further above for examples of optics. In embodiments, the optics may comprise an integrator, like a “Koehler integrator” (or “Kohler integrator”).

[0088] Especially, in embodiments, the optical elements further comprise one or more optical integrators. In embodiments, the optical integrators may be individually selected from the group comprising: a small-angle diffuser, a transmissive volume diffuser, a transmissive surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a flyeye lens array, and an integrating polygonal light pipe.

[0089] At least one optical integrator may, in embodiments, be configured in an optical path between the first light generating device and the luminescent material. Additionally or alternatively, at least one optical integrator may, in embodiments, be configured in an optical path between the first light generating device and the diffuser assembly. In some embodiments, one optical integrator may be configured in an optical path between the first light generating device and both the diffuser assembly and the luminescent material. In alternative embodiments, the optical integrator between the first light generating device and the diffuser assembly and the optical integrator between the first light generating device and the luminescent material may be separate (or distinct) optical integrators. Yet further, in embodiments, the optical elements may comprise an optical integrator configured between the luminescent material and the light exit. Hence, in specific embodiments, the optical elements may further comprise one or more optical integrators, wherein the optical integrators may be individually selected from the group comprising: a small-angle diffuser, a transmissive volume diffuser, a transmissive surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a fly-eye lens array, and an integrating polygonal light pipe; and wherein (i) at least one optical integrator may be configured in an optical path between the first light generating device and the luminescent material, and (ii) at least one optical integrator may be configured in an optical path between the first light generating device and the diffuser assembly. Such embodiments may be beneficial as the optical integrators may improve spot sizes and light distributions in spots of light on the different elements such as e.g. the diffuser and the luminescent material. Therewith, the lifetime of these elements may be improved. Furthermore, the optical integrators may help homogenize the light propagating through the light generating system, which may provide the advantage of more homogeneously distributed system light.

[0090] Furthermore, in embodiments, the optical elements may comprise one or more of condensing (or focusing) optical elements and collecting (or collimating)) optical elements. In embodiments, at least one condensing and / or collimating optical element may be configured upstream of the (reflective) diffuser. Similarly, in embodiments, at least one condensing and / or collimating optical element may be configured upstream of the luminescent material. Further, in embodiments, at least one condensing and / or collimating optical element may be configured upstream of the light exit. Yet further, in embodiments, at least one condensing and / or collimating optical element may be configured downstream of the first (and optionally second) light generating device.

[0091] In embodiments, a condensing optical element may be configured to condense or focus the light received by the condensing optical element. The condensing optical element may thus, in embodiments, be configured to provide a focused beam of device light in an optical path to the a downstream part of the light generating system (e.g. the luminescent material or the light exit). Conversely, in embodiments, the collecting optical element may be configured to collect and collimate the light received by the collecting optical element. The collecting optical element may thus, in embodiments, be configured to provide a collimated beam of light in an optical path to a downstream part of the light generating system (e.g. the luminescent material or the light exit). Therefore, in embodiments, the condensing optical element and the collimating optical element may both be configured transmissive for ((diffused) device and / or luminescent material) light.

[0092] In embodiments, a condensing and / or collecting optical element may comprise a lens. Especially, in embodiments, a condensing and / or collecting optical element may comprise a surface configured to condense and / or collimate an incoming parallel beam of light, such as a lens surface. In such embodiments, the condensing and collecting (or collimating) optical elements may comprise one or more positive lenses. In some embodiments, it may be preferred to apply a set of two, or possibly three positive condenser lenses to enable a large effective numerical aperture.

[0093] In embodiments, a condensing and / or collecting optical element may for example comprise one or a curved lens surface, a Fresnel-type lens surface, and a metasurface (i.e., a flat textured surface). Especially, in embodiments, a condenser and / or collecting optical element may comprise an aspherical lens. However, in alternative embodiments (in dependence on desired requirements for the out-put system light), a condensing and / or collecting optical element may also comprise a spherical lens.

[0094] Furthermore, in embodiments, a condensing and / or collecting optical element may comprise a material having low absorption for (at least) the spectral range of the device light. 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 condensing and / or collecting optical elements may comprise fused silica (FS). Moreover, in embodiments, each condensing and / or collecting optical element may comprise a material having an absorption coefficient individually selected from the range of <0.01 cm'1for the spectral range of the received device light. More especially, in embodiments, each condenser and / or collecting optical element may comprise a material having an absorption coefficient individually selected from the range of <0.005 cm'1, such as from the range of <0.01 cm'1, for the spectral range of the received device light. Note that, in embodiments, a condensing optical element and a collecting optical element may comprise essentially the same type of optical element. For example, in embodiments, a single positive lens may be applied for condensing (first) device light onto the diffuser, while that same lens may be applied for collimating diffused device light propagating from the diffuser. However, this may not necessarily be the case.

[0095] In embodiments, the light generating system may further comprise a control system. The control system may especially be configured to control one or more of a correlated color temperature, a color rendering index, a spectral power distribution, and a radiant flux of the system light. In embodiments, the control system may e.g. control said characteristics of the system light by controlling (the power of) one or more of the light generating devices, especially at least the first light generating device. Additionally or alternatively, in embodiments, the control system may e.g. control optical characteristics of the system light by controlling the polarization of device light in the light generating system (e.g. through the use of a polarizing beam splitter as described above). In specific embodiments, the light generating system may comprise a control system, wherein the control system may be configured to control one or more of (i) the color point of the system light, the luminous flux of the system light, (iii) the color rendering index (CRI) of the system light, and (iv) the correlated color temperature (CCT) of the system light by controlling the first light generating device.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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, that can only operate in a single operation mode (i.e. “on”, without further tunability).

[0101] 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. 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.

[0102] 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.

[0103] 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.

[0104] The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. 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 440-490 nm wavelength range.

[0105] 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 (see also below). 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.

[0106] The term “light source” may in principle relate to any light source known in the art. The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources.

[0107] The light source may have a light escape surface. 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.

[0108] 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.

[0109] 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.

[0110] The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. 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).

[0111] 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, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light source. 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).

[0116] 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.

[0117] The term “light source” may (thus) in embodiments also refer to a light source that is (also) based on conversion of light, such as a light source in combination with a luminescent converter material. Hence, the term “light source” may also refer to a combination of an LED with a luminescent material configured to convert at least part of the LED radiation, or to a combination of a (diode) laser with a luminescent material configured to convert at least part of the (diode) laser radiation.

[0118] In embodiments, the term “light source” may also refer to a combination of a light source, like an LED, and an optical filter, which may change the spectral power distribution of the light generated by the light source. Especially, the term “light generating device” may be used to address a light source and further (optical components), like an optical filter and / or a beam shaping element, etc.

[0119] 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 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.

[0120] 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.

[0121] 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.

[0122] 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).

[0123] 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, trivalent uranium doped calcium fluoride (U:CaF2) solid-state laser, Ytterbium doped glass laser (rod, plate / chip, and fiber), Ytterbium YAG (Yb:YAG) laser, Yb2Os (glass or ceramics) laser, etc.

[0124] 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; AhOsYi3) laser. For instance, considering second and third harmonic generation, such light sources may be used to generated blue light.

[0125] 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.

[0126] 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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).

[0131] 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.

[0132] 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.

[0133] Instead of the term “solid state light source” also the term “semiconductorbased 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. Hence, the light generating device may comprise one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.

[0134] 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.

[0135] 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.

[0136] 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. Especially, a superluminescent diode may be a semiconductor light source, where the spontaneous emission light is amplified by stimulated emission in the active region of the device. Such emission is called “super luminescence”. Superluminescent diodes combine the high power and brightness of laser diodes with the low coherence of conventional lightemitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Superluminescent diodes may combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode.

[0137] 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 vehicle light, an automotive lighting device, a stage lighting device, an (entertainment) moving head lighting device, a spot light, a search light, a disinfection device, a photochemical reactor, 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 light generating devices, the luminescent material, the diffuser assembly, and the optics.

[0138] 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.

[0139] BRIEF DESCRIPTION OF THE DRAWINGS

[0140] 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:

[0141] Figs. 1-4 schematically depict some embodiments of the light generating system.

[0142] Fig. 5 schematically depicts some applications of the light generating system in lighting devices. The schematic drawings are not necessarily to scale.

[0143] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0144] Figs. 1 and 2 schematically depict a light generating system 1000 comprising a first light generating device 110, a luminescent material 200, a diffuser assembly 700, optical elements 500, and a light exit 1090. In embodiments, the first light generating device 110 may be configured to generate first device light 111. Therefore, the first light generating device 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. Furthermore, in embodiments, the first light generating device 110 may comprise a first laser bank 1100. Especially, the first laser bank 1100 may comprise a light emitting arrangement comprising a 2D array of a plurality of first laser diodes 1110 arranged on a thermally conductive carrier and a lens array. Especially, in embodiments, the lens array may have a plurality of collimator lenses corresponding to the first laser diodes 1110, such that each laser diode of the plurality of first laser diodes 1110 may comprise a collimator lens for collimating laser light emitted by the laser diode 1110.

[0145] Moreover, in embodiments, in an operational mode of the light generating system 1000 the first device light 111 may have a wavelength selected from the wavelength range of 420-490 nm, like selected from the wavelength range of 430-490 nm. Hence, in embodiments, the first device light 111 may be blue light. However, in alternative embodiments, the first device light 111 may have essentially any wavelength, especially from the visible wavelength range (i.e. 380-780 nm). Further, in embodiments, the first device light 111 may comprise polarized light.

[0146] In embodiments, the optical elements 500 may comprise one or more redirection optical elements 1500. Especially, as depicted in Figs. 1 and 2, the one or more redirection optical elements 1500 may comprise at least a first redirection optical element 1510. In embodiments, the first redirection optical element 1510 may be configured in a light-receiving relationship with the first light generating device 110. Especially, in embodiments, (during operation of the light generating system 1000) the first redirection optical element 1510 may be configured to direct the first device light 111 in an optical path to the diffuser assembly 700. Additionally, in embodiments, (during operation of the light generating system 1000) the first redirection optical element 1510 may be configured to direct at least part of diffused device light 711 in an optical path to the luminescent material 200. In embodiments, the first device light 111 received by the first redirection optical element 1510 may comprise linear polarized light. As depicted in Figs. 1 and 2, in embodiments, the first device light 111 may comprise p-polarized light (indicated with the double arrow symbol), whereas diffused device light 711 (see also further below) may comprise s-polarized light (indicated with the black dot symbol). However, in alternative embodiments (not depicted), the first device light 111 may comprise s-polarized light, whereas diffused device light 711 may comprise p-polarized light. Therefore, in embodiments, the first redirection optical element 1510 may be configured to (re-)direct the first device light 111 and the diffused device light 711 received by the first redirection optical element 1510 in dependence of their respective polarizations.

[0147] In particular, in embodiments, the first redirection optical element 1510 may comprise a polarizing beam splitter (PBS). In embodiments, such as depicted in the Figs 1-5, the first redirection optical element 1510 (i.e. the polarizing beam splitter PBS) may be configured to transmit first device light 111 comprising a first linear polarization (here especially p-polarization) and to reflect diffused device light 711 comprising a second linear polarization (here especially s-polarization), different from the first linear polarization. Alternatively, in embodiments, the first redirection optical element 1510 (i.e. the polarizing beam splitter PBS) may be configured to reflect first device light 111 comprising the first linear polarization and to transmit diffused device light 711 comprising the second linear polarization, different from the first linear polarization. Especially, in embodiments, the first redirection optical element 1510 may be configured to provide first device light 111 to the diffuser assembly 700.

[0148] The diffuser assembly 700 may, in embodiments, comprise a diffuser 710 and a quarter waveplate 720. In embodiments, the diffuser 710 may comprise a polarization maintaining diffuser. Furthermore, as depicted here, in embodiments, the diffuser 710 may be configured in the reflective mode. Especially, in embodiments, the diffuser 710 may be configured to diffuse at least part of the first device light 111 received by the diffuser 710 into diffused device light 711. The diffused device light 711 may, in embodiments, have a full width half maximum (FWHM) of at least 5°, such as selected from the range of 5-60°. Furthermore, in embodiments, the quarter waveplate 720 may be configured in an optical path between the first redirection optical element 1500 and the diffuser 710. The light generating system 1000 may especially be configured such that first device light 111 reaching the quarter waveplate 720 may comprise linearly polarized light. The quarter waveplate 720 may then be configured to convert linear polarized light received by the quarter waveplate 720 into elliptical polarized light. Especially, in embodiments, the quarter waveplate 720 may be configured to provide elliptically polarized first device light 111 to the diffuser assembly 700. Additionally, in embodiments, the quarter waveplate 720 may be configured to convert elliptical polarized (diffused) light (711) received by the quarter waveplate 720 into linear polarized light. As such, in embodiments, the diffused device light 711 may propagate from the diffuser 710 via the quarter waveplate 720 back to the first polarizing beam splitter 1510. Thus, in embodiments, the diffuser assembly 700 may be configured to provide the diffused device light 711 in an optical path to the luminescent material 200 via the first redirection optical element 1510.

[0149] In embodiments, the luminescent material 200 may thus be configured in a light-receiving relationship with the first redirection optical element 1510 (optionally via further optical elements 500). Especially, in embodiments, the luminescent material 200 may be configured to convert at least part of the diffused device light 711 received by the luminescent material 200 into luminescent material light 201. Especially, in embodiments, luminescent material 200 may be configured to convert at least 60% of the diffused device light 711 received by the luminescent material 200 into luminescent material light 20E

[0150] As depicted in Figs. 1-4, the luminescent material 200 may be configured in the transmissive mode. However, in alternative embodiments (not depicted), the luminescent material 200 may also be configured in the reflective mode. The luminescent material 200 may thus especially be configured in the transmissive mode. The luminescent material 200 may especially be configured on (or embedded in) a support 800. In embodiments, the support 800 may comprise one or more of a heat sink or a heat spreader. Especially, in embodiments, the support 800 may comprise a thermally conductive material.

[0151] Further, in embodiments, the optical elements 500 may be configured to direct at least part of the luminescent material light 201 (propagating from the luminescent material 200) in an optical path to the light exit 1090. The light exit 1090 may herein comprise an opening or a last optical element, like a lens (including a lens array), a diffuser, etc. Hence, in embodiments, the light generating system 1000 may be configured to generate in an operational mode of the light generating system 1000 system light 1001 comprising at least part of the luminescent material light 201.

[0152] In specific embodiments, the luminescent material 200 may be configured to convert at least 90% of the diffused device light 711 received by the luminescent material 200 into luminescent material light 201. In such embodiments, the luminescent material 200 may be configured to transmit less than 2 % of the diffused device light 711 received by the luminescent material 200. Hence, in such embodiments, the light generating system 1000 may be configured to generate in an operational mode of the light generating system 1000 system light 1001 essentially consisting of luminescent material light 201.

[0153] Alternatively, in embodiments, the luminescent material 200 may be configured to transmit at least 10% of the diffused device light 711 received by the luminescent material 200 (as unconverted diffused device light 711) in an optical path to the light exit 1090. Hence, in embodiments, the optical elements 500 may be further configured to direct at least part of the diffused device light 711 transmitted by the luminescent material 200 in an optical path to the light exit 1090. In such embodiments, the light generating system 1000 may be configured to generate in an operational mode of the light generating system 1000 system light 1001 comprising at least part of the luminescent material light 201 and at least part of the diffused device light 711 (transmitted by the luminescent material 200).

[0154] The optical elements 500 of the light generating system 1000 may especially comprise one or more condensing and / or collimating optics. For example, as depicted here, the optical elements 500 may comprise a lens 560 configured between the first redirection optical element 1510 and the diffuser assembly 700, a lens 560 configured between the first redirection optical element 1510 and the luminescent material 200, and a lens 560 configured between the luminescent material 200 and the light exit 1090. However, other configurations and additional optical elements 500 may be possible as well, see e.g. further below.

[0155] For example, in embodiments, the optical elements 500 may further comprise one or more optical integrators 570. In embodiments, the optical integrators 570 may be individually selected from the group comprising: a small-angle diffuser, a transmissive volume diffuser, a transmissive surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a fly-eye lens array, and an integrating polygonal light pipe. Especially, in embodiments, at least one optical integrator 570 may be configured in an optical path between the first light generating device 110 and the luminescent material 200. Additionally or alternatively, in embodiments, at least one optical integrator 570 may be configured in an optical path between the first light generating device 110 and the diffuser assembly 700.

[0156] Further, in embodiments, the optical elements 500 may comprise one or more of a dichroic reflector 510 and a reflective polarizer 520 configured in an optical path between the first redirection optical element 1510 and the luminescent material 200. Especially, in embodiments, the one or more of a dichroic reflector 510 and a reflective polarizer 520 may be configured to transmit (first and / or) diffused device light (111,)711. Additionally, in embodiments, the one or more of a dichroic reflector 510 and a reflective polarizer 520 may be configured to at least partly reflect luminescent material light 201.

[0157] In embodiments, the light generating system 1000 may further comprise a control system 300. Especially, the control system 300 may be configured to control one or more of (i) the color point of the system light 1001, the luminous flux of the system light 1001, (iii) the color rendering index (CRI) of the system light 1001, and (iv) the correlated color temperature (CCT) of the system light 1001. The control system may especially control said characteristics of the system light 1001 by controlling the first light generating device

[0158] 110.

[0159] As depicted in Fig. 3, in embodiments, the light generating system 1000 may comprise a second light generating device 120. In embodiments, the second light generating device 120 may be configured to generate second device light 121. Therefore, the second light generating device 120 may comprise a second solid-state light source 20 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction lightemitting diodes. Furthermore, in embodiments, the second light generating device 120 may comprise a second laser bank 1200. Especially, the second laser bank 1200 may comprise a light emitting arrangement comprising a 2D array of a plurality of second laser diodes 1220 arranged on a thermally conductive carrier and a lens array. Especially, in embodiments, the lens array may have a plurality of collimator lenses corresponding to the second laser diodes 1220, such that each laser diode of the plurality of second laser diodes 1220 may comprise a collimator lens for collimating laser light emitted by the laser diode 1220.

[0160] In embodiments, the first redirection optical element 1510 may be configured in a light-receiving relationship with the second light generating device 120. Especially, in embodiments, (during operation of the light generating system 1000) the first redirection optical element 1510 may be configured to direct the second device light 121 in an optical path to the diffuser assembly 700. Additionally, in embodiments, (during operation of the light generating system 1000) the first redirection optical element 1510 may be configured to direct at least part of diffused second device light 721 in an optical path to the luminescent material 200. In embodiments, the second device light 121 received by the first redirection optical element 1510 may comprise linear polarized light. In embodiments (not depicted), the second device light 121 may comprise the same linear polarization as the first device light

[0161] 111, (e.g. as depicted p-polarized light), whereas diffused second device light 721 (see also further below) may comprise the same linear polarization as the diffused device light 711 (e.g. as depicted s-polarized light). In such embodiments, the second device light 121 may propagate through the light generating system 1000 in the same way as the first device light 111. Similarly, in such embodiments, the diffused second device light 721 may propagate through the light generating system 1000 in the same way as the diffused (first) device light 711. Hence, the first device light 111 and the second device light 121 may be diffused (into diffused device light 711 and diffused second device light 721, respectively) by the same diffuser 710. For example, in such embodiments, the second device light 121 may (also) have a wavelength selected from the wavelength range of 420-490 nm, such as selected from the wavelength range of 430-490 nm. Hence, in embodiments, the first device light 111 and the second device light 121 may be blue light. However, this may not necessarily be the case. In embodiments, the first device light 111 and the second device light 121 may have a wavelength individually selected from the visible wavelength range (i.e. 380-780 nm).

[0162] However, in alternative embodiments as depicted in Fig. 3, the second device light 121 may comprise s-polarized light, whereas diffused second device light 721 may comprise p-polarized light. In such embodiments, the light generating system may further comprise a second diffuser assembly 2700. The second diffuser assembly 2700 may, in embodiments, comprise a second diffuser 2710 and a second quarter waveplate 2720. In embodiments, the second diffuser 2710 may comprise a polarization maintaining diffuser. Furthermore, as depicted here, in embodiments, the second diffuser 2710 may be configured in the reflective mode. Especially, in embodiments, the second diffuser 2710 may be configured to diffuse at least part of the second device light 121 received by the second diffuser 2710 into diffused second device light 721. The diffused second device light 721 may, in embodiments, have a full width half maximum (FWHM) of at least 5°, such as selected from the range of 5-60°. Furthermore, in embodiments, the second quarter waveplate

[0163] 720 may be configured in an optical path between the first redirection optical element 1500 and the second diffuser 2710. The light generating system 1000 may especially be configured such that second device light 121 reaching the second quarter waveplate 2720 may comprise linearly polarized light. The second quarter waveplate 2720 may then be configured to convert linear polarized light received by the second quarter waveplate 2720 into elliptical polarized light. Especially, in embodiments, the second quarter waveplate 2720 may be configured to provide elliptically polarized second device light 121 to the second diffuser

[0164] 2710. Additionally, in embodiments, the second quarter waveplate 2720 may be configured to convert elliptical polarized (diffused second device) light (721) received by the second quarter waveplate 2720 into linear polarized light. As such, in embodiments, the diffused second device light 721 may propagate from the second diffuser 2710 via the second quarter waveplate 2720 back to the first polarizing beam splitter 1510. Thus, in embodiments, the second diffuser assembly 2700 may be configured to provide the diffused second device light

[0165] 721 in an optical path to the luminescent material 200 via the first redirection optical element In such embodiments, the first redirection optical element 1510 may be configured to (i) transmit first device light 111 and diffused second device light 721 comprising the first linear polarization (here especially p-polarization) and (ii) reflect diffused device light 711 and second device light 121 comprising the second linear polarization (here especially s-polarization). Alternatively, in embodiments, the first redirection optical element 1510 may be configured to (i) transmit first device light 111 and diffused second device light 721 comprising the first linear polarization (here especially p- polarization) and (ii) reflect diffused device light 711 and second device light 121 comprising the second linear polarization (here especially s-polarization). Especially, in embodiments, the first redirection optical element 1510 may be configured to provide second device light 121 to the second diffuser assembly 2700. For example, in such embodiments, the second device light 121 may have a wavelength selected from the wavelength range of 490-780 nm. Hence, in embodiments, the second device light 121 may be green, yellow, or red light. However, this may not necessarily be the case. In embodiments, the first device light 111 and the second device light 121 may have a wavelength individually selected from the visible wavelength range (i.e. 380-780 nm).

[0166] Furthermore, in embodiments comprising the second light generating device 120, the luminescent material 200 may (in an operational mode of the light generating system 1000) be configured to convert at least part of the diffused second device light 721 received by the luminescent material 200 into luminescent material light 201. Especially, in embodiments, the luminescent material 200 may be configured to convert at least 60% of the diffused second device light 721 received by the luminescent material 200 into luminescent material light 201.

[0167] As depicted in Fig. 4, in embodiments, the optical elements 500 may comprise a second redirection optical element 1520. In embodiments, the second redirection optical element 1520 may be configured in a light receiving relationship with the diffuser 710 via the first redirection optical element 1510. Moreover, in embodiments, the second redirection optical element 1520 may be configured to direct a first part 71 la of the diffused device light 711 in an optical path to the luminescent material 200. Additionally, in embodiments, the second redirection optical element 1520 may be configured to direct a second part 71 lb of the diffused device light 711 in an optical path to the light exit 1090 (while bypassing the luminescent material 200). Hence, in such embodiments, part of the diffused device light 711 may be provided in an optical path to the luminescent material 200, whereas another part of the diffused device light 711 may be re-directed in a separate optical path (to the light exit 1090) bypassing the luminescent material 200.

[0168] Especially, in such embodiments, the light generating system 1000 may comprise the second diffuser assembly 2700. However, in such embodiments, the second diffuser assembly 2700 may comprise the second diffuser 2710 (without the second quarter waveplate (2720). Especially, in embodiments, the second diffuser 2710 may comprise a transmissive diffuser. The second diffuser 2710 may, in such embodiments, be configured to diffuse the diffused (first) device light 711 received by the second diffuser 2710 into secondary diffused device light 2711. More especially, the secondary diffused device light 2711 may have a full width at half maximum (FWHM) selected from the range of 40-120°. In other words, in embodiments, the diffuser 2710 may have a diffusion angle selected from the range of 40-120°. Especially, in embodiments, the secondary diffused device light 2711 may have a FWHM larger than the FWHM of the first diffused device light 71 E

[0169] Further, in such embodiments, the second diffuser 2710 may be configured in an optical path between the second redirection optical element 1520 and the light exit 1090. Especially, the second diffuser 2710 may be configured to receive the second part 71 lb of the diffused device light 71 E More especially, the second diffuser 2710 may be configured to diffuse at least part of the (second part 71 lb of the) diffused device light 711 received by the second diffuser 2710 into secondary diffused device light 27 IE In such embodiments, the second diffuser 2710 may further be configured to provide the secondary diffused device light 2711 in an optical path to the light exit 1090.

[0170] Therefore, in embodiments, optical elements 500 may further comprise a third redirection optical element 1530. In embodiments, the third redirection optical element 1530 may comprise a dichroic-based redirection optical element (i.e. a dichroic beam combiner). Especially, in embodiments, the third redirection optical element 1530 may be configured in a light received relationship with both the luminescent material 200 and the second diffuser assembly 2700. More especially, in embodiments, the third redirection optical element 1530 may be configured in an optical path between (i) the luminescent material 200 and the light exit 1090, and (ii) the second diffuser assembly 2700 and the light exit 1090. In embodiments, the third redirection optical element 1530 may be configured to direct the luminescent material light 201 and the secondary diffused device light 2711 received by the third redirection optical element 1530 in an optical path to the light exit 1090.

[0171] Especially, in embodiments as depicted here, the third redirection optical element 1530 may be configured to transmit the luminescent material light 201 received by the third redirection optical element 1530 in an optical path to the light exit 1090. Additionally, in such embodiments, the third redirection optical element 1530 may be configured to reflect the secondary diffused device light 2711 received by the third redirection optical element 1530 in an optical path to the light exit 1090. Alternatively, in embodiments (not depicted), the third redirection optical element 1530 may be configured to reflect the luminescent material light 201 received by the third redirection optical element 1530 in an optical path to the light exit 1090. Additionally, in such embodiments, the third redirection optical element 1530 may be configured to transmit the secondary diffused device light 2711 received by the third redirection optical element 1530 in an optical path to the light exit 1090.

[0172] Hence, in embodiments, the light generating system 1000 may be configured to generate in an operational mode of the light generating system 1000 system light 1001 comprising at least part of the luminescent material light 201 and at least part of the secondary diffused device light 2711. Especially, in embodiments, in an operational mode of the light generating system 1000 (i) 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.

[0173] Furthermore, as depicted in Fig. 4, the light generating system 1000 may comprise a rotating element 1250. In embodiments, one or more of the luminescent material 200 and the diffuser 710 may be configured on the rotating element 1250. For example, as depicted here, the diffuser 710 and the luminescent material 200 may each be configured on a separate rotating element 1250. Such a rotating element 1250 may e.g. comprise a rotating (phosphor) wheel or a rotating rod.

[0174] Fig. 5 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 coupled to the light generating system 1000. Fig. 5 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. 5 schematically depicts embodiments of 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, a search light, 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, 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 and reference 1310 to a ceiling; reference 1307 refers to a wall.

[0175] 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".

[0176] 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.

[0177] 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.

[0178] 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.

[0179] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. 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”.

[0180] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0181] 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. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments ol) the method as described herein.

[0182] 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.

[0183] 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.

[0184] 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

CLAIMS:

1. A light generating system (1000) comprising a first light generating device(110), a luminescent material (200), 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 optical elements (500) comprise one or more redirection optical elements (1500) at least comprising a first redirection optical element (1510); wherein the first redirection optical element (1510) is configured in a light-receiving relationship with the first light generating device (110); wherein the first redirection optical element (1510) is configured to (i) direct the first device light (111) in an optical path to the diffuser assembly (700), and to (ii) direct at least part of diffused device light (711) in an optical path to the luminescent material (200). the diffuser assembly (700) comprises (a) a diffuser (710), 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 at least part of the first device light (111) received by the diffuser (710) into diffused device light (711), wherein the diffused device light (711) has a full width half maximum of at least 5°; and (b) a quarter waveplate (720), wherein the quarter waveplate (720) is configured in an optical path between the first redirection optical element (1500) and the diffuser (710); wherein the light generating system (1000) is configured such that first device light (111) reaching the quarter waveplate (720) comprises linear polarized light; wherein the quarter waveplate (720) is configured to convert linear polarized light received by the quarter waveplate (720) into elliptical polarized light and to convert elliptical polarized light received by the quarter waveplate (720) into linear polarized light; wherein the diffuser assembly (700) is configured to provide the diffused device light (711) in an optical path to the luminescent material (200) via the first redirection optical element (1510);the luminescent material (200) is configured to convert at least part of the diffused device light (711) received by the luminescent material (200) into luminescent material light (201); the optical elements (500) are configured to direct at least part of the luminescent material light (201) in an optical path to the light exit (1090); and the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) system light (1001) comprising at least part of the luminescent material light (201).

2. The light generating system (1000) according to claim 1, wherein the first redirection optical element (1510) comprises a polarizing beam splitter (PBS), and wherein the polarizing beam splitter (PBS) is configured (a) to transmit first device light (111) comprising a first linear polarization and to reflect diffused device light (711) comprising a second linear polarization, different from the first linear polarization, or (b) to reflect first device light (111) comprising the first linear polarization and to transmit diffused device light (711) comprising the second linear polarization, different from the first linear polarization.

3. The light generating system (1000) according to any one of the preceding claims, wherein the diffused device light (711) has a full width half maximum selected from the range of 5-60°.

4. The light generating system (1000) according to any one of the preceding claims 1-3, wherein the luminescent material (200) is configured in the transmissive mode wherein the luminescent material (200) is configured to convert at least 60% of the diffused device light (711) received by the luminescent material (200) into luminescent material light (201).

5. The light generating system (1000) according to claim 4, wherein the luminescent material (200) is further configured to transmit at least 5% of the diffused device light (711) received by the luminescent material (200) in an optical path to the light exit (1090); wherein the optical elements (500) are further configured to direct at least part of the diffused device light (711) transmitted by the luminescent material (200) in an optical path to the light exit (1090); and wherein the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) system light (1001) comprisingat least part of the luminescent material light (201) and at least part of the diffused device light (711) transmitted by the luminescent material (200).

6. The light generating system (1000) according to any one of the preceding claims 1-3, wherein the luminescent material (200) is configured in the transmissive mode, wherein the luminescent material (200) is configured to convert at least 90% of the diffused device light (711) received by the luminescent material (200) into luminescent material light (201) and wherein the luminescent material (200) is configured to transmit less than 2% of the diffused device light (711) received by the luminescent material (200).

7. The light generating system (1000) according to any one of the preceding claims, wherein the optical elements (500) comprise a second redirection optical element (1520), wherein the second redirection optical element (1520) is configured in a light receiving relationship with the diffuser (710) via the first redirection optical element (1510); wherein the second redirection optical element (1520) is configured to (i) direct a first part (711a) of the diffused device light (711) in an optical path to the luminescent material (200), and to (ii) direct a second part (711b) of the diffused device light (711) in an optical path to the light exit (1090) while bypassing the luminescent material (200).

8. The light generating system (1000) according to claim 7, further comprising a second diffuser assembly (2700), wherein the second diffuser assembly (2700) comprises a second diffuser (2710); wherein the second diffuser (2710) is configured in an optical path between the second redirection optical element (1520) and the light exit (1090); wherein the second diffuser (2710) is configured to receive the second part (711b) of the diffused device light (711), wherein the second diffuser (2710) is configured to diffuse at least part of the second part (71 lb) of the diffused device light (711) received by the second diffuser (2710) into secondary diffused device light (2711); wherein the second diffuser (2710) is configured to provide the secondary diffused device light (2711) in an optical path to the light exit (1090); wherein the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) system light (1001) comprising at least part of the luminescent material light (201) and at least part of the secondary diffused device light (2711).

9. The light generating system (1000) according to claim 7, wherein the second diffuser (2710) comprises a transmissive diffuser; and wherein the secondary diffused device light (2711) has a full width half maximum larger than the full width half maximum of the first diffused device light (711), wherein the full width half maximum of the secondary diffused device light (2711) is selected from the range of 40-120°.

10. The light generating system (1000) according to any one of the preceding claims, wherein in an operational mode of the light generating system (1000) (i) the first device light (111) has a wavelength selected from the wavelength range of 430-490 nm, and (ii) 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.

11. The light generating system (1000) according to any one of the preceding claims, wherein the optical elements (500) comprise one or more of a dichroic reflector (510) and a reflective polarizer (520) configured in an optical path between the first redirection optical element (1510) and the luminescent material (200), wherein the one or more of a dichroic reflector (510) and a reflective polarizer (520) is configured to (i) transmit diffused device light (711) and (ii) at least partly reflect luminescent material light (201).

12. The light generating system (1000) according to any one of the preceding claims, wherein the first light generating device (110) comprises a first laser bank (1100), wherein the first laser bank (1100) comprises a light emitting arrangement comprising a 2D array of a plurality of first laser diodes (1110) arranged on a thermally conductive carrier and a lens array having a plurality of collimator lenses corresponding to the first laser diodes (1110) such that each laser diode of the plurality of first laser diodes (1110) comprises a collimator lens for collimating laser light emitted by the laser diode (1110).

13. The light generating system (1000) according to any one of the preceding claims, wherein the optical elements (500) further comprise one or more optical integrators (570), wherein the optical integrators (570) are individually selected from the group comprising: a small-angle diffuser, a transmissive volume diffuser, a transmissive surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a fly-eye lens array, and an integrating polygonal light pipe; and wherein (i) at least one optical integrator(570) is configured in an optical path between the first light generating device (110) and the luminescent material (200), and (ii) at least one optical integrator (570) is configured in an optical path between the first light generating device (110) and the diffuser assembly (700).

14. The light generating system (1000) according to any one of the preceding claims, further comprising a control system (300), wherein the control system (300) is configured to control one or more of (i) the color point of the system light (1001), the luminous flux of the system light (1001), (iii) the color rendering index (CRI) of the system light (1001), and (iv) the correlated color temperature (CCT) of the system light (1001) by controlling the first light generating device (110).

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

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