Laser diffusion in single loop for laser-phosphor light engines

Abstract

The invention provides a light generating system (1000) comprising a blueish light generating device (120), an diffuser light generating device (130), optics (500), a diffuser assembly (700), and a light exit (1090); wherein: (A) the blueish light generating device (120) is configured to provide blueish device light (121) having a blueish centroid wavelength (λc2) selected from the wavelength range of 430-490 nm, and comprises a blueish solid state light source (20); (B) the diffuser light generating device (130) is configured to provide diffuser device light (131) having a diffuser centroid wavelength (λc3) selected from the wavelength range of 470-780 nm, and comprises a diffuser solid state light source (30); wherein |λc3-λc2| ≥ 10 nm; (C) the blueish and diffuser solid state light sources (20,30) are selected from the group comprising laser diodes, superluminescent diodes, and stacked multi-junction light-emitting diodes; (D) the optics (500) comprise a diffuser redirection optical element (530), configured in an optical path between (i) the blueish light generating device (120) and (ii) the diffuser light generating device (130) and the diffuser assembly (700); wherein the diffuser redirection optical element (530) is configured to direct (i) blueish device light (121) and (ii) diffuser device light (131) into an optical path to the diffuser assembly (700); (E) the diffuser assembly (700) comprises a diffuser (710) configured to diffuse at least part of the blueish device light (121) into diffused blueish device light (721), and at least part of the diffuser device light (131) into diffused diffuser device light (731); (F) the diffuser redirection optical element (530) is further configured to direct (i) the diffused blueish device light (721), and (ii) the diffused diffuser device light (731) into an optical path to the light exit (1090); wherein (i) an optical axis of the blueish device light (121) upstream of the diffuser redirection optical element (530), and (ii) an optical axis of the diffused blueish device light (721) and the diffused diffuser device light (731) downstream of the diffuser redirection optical element (530) are co-axial; wherein the light generating system (1000) is configured such, that the blueish device light (121) and the diffuser device light (131) are incident on the diffuser redirection optical element (530) from orthogonal directions; and (G) the light generating system (1000) is configured to generate system light (1001), wherein in a first operational mode the system light (1001) comprises at least part of (i) the diffused blueish device light (721) and (ii) the diffused diffuser device light (731).

Description

[0001] 2025PF80043

[0002] 1

[0003] LASER DIFFUSION IN SINGLE LOOP FOR LASER-PHOSPHOR LIGHT ENGINES

[0004] FIELD OF THE INVENTION

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

[0006] BACKGROUND OF THE INVENTION

[0007] Lighting fixtures are known in the art. For instance, WO2022143318A1 describes a light emitting device, comprising a first light source, a second light source, a dichroic mirror, a wavelength conversion apparatus, a first light path adjusting apparatus or a second light path adjusting apparatus, and a first scattering optical system. The color temperature of the emergent light of the light emitting device can be freely adjusted by independently adjusting the power of the first light source and the power of the second light source.

[0008] SUMMARY OF THE INVENTION

[0009] Laser-phosphor systems may allow generation of high brightness light and may therefore be used in projection systems, including displays such as cinema projectors and projectors for home, school, and office applications, car front lighting, search lighting, stage lighting, architectural lighting, and special lighting applications. However, such light engine may be capable to generate only a single color point as defined by the luminescent converter (and optionally remaining pump light (for exciting the luminescent converter)). Creation of a product range providing different color points may be difficult as it may require multiple unique components to be designed, qualified, produced, and kept in stock. In other cases, e.g. in RGB LCD-based projection systems, the maximum brightness may be limited by the components used, the engine volume may be large due to the many components, and the system cost may be high due to the many dedicated components. A way to combine pump light and luminescent light may be to use a polarizing beam splitter for the pump light, by which part of the light is reflected to the luminescent material and part is transmitted to a diffuser. However, in general the diffused light may to a large degree be depolarized, resulting in relatively high losses of diffused blue light at the beam combiner where it is2025PF80043

[0010] 2

[0011] combined with the luminescent light into white output light. In addition, using a single laser source (that may comprise multiple laser diodes) may significantly limit the maximum output power due to size limitations to the optical components.

[0012] In many laser-based light engine designs the effective usage of the laser light sources, in case there is more than one source, depends on the light source design (what is the maximum output of the sources used) in relation to the targeted output power and the targeted color point of the (white) light output. There is a need for architectures that enable optimal use of the laser light sources while operating the engine at any of a range of selectable output white light color points (or CCT’s), as the choice in output powers of the laser devices may be relatively limited and installation of redundant laser diodes may be relatively expensive. In addition, there is a need to increase both the color rendering properties of laser-based light engines, as well as the color gamut properties. Furthermore, while high CCT’s are acceptable for e.g. automotive front lighting and some search light and stage lighting applications, there is an increasing need for medium to low CCT in high flux and high brightness light sources. Especially, there appears to be a desire for tunable laser-phosphor light engines that make more efficient use of the installed power of more than two laser banks while not increasing the light source etendue, and that provide an output with an enlarged CCT range and / or improved color gamut and / or improved color rendering properties. 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.

[0013] According to a first aspect, the invention provides a light generating system comprising a blueish light generating device, a diffuser light generating device, optics, a diffuser assembly, and a light exit. The blueish light generating device may be configured to provide blueish device light having a blueish centroid wavelength (λc2) selected from the wavelength range of 430-490 nm. Further, the blueish light generating device may comprise a blueish solid state light source. Similarly, the diffuser light generating device may be configured to provide diffuser device light having a diffuser centroid wavelength (λc3) selected from the wavelength range of 470-780 nm. Further, the diffuser light generating device may comprise a diffuser solid state light source. In embodiments, |λc3-λc2| ≥ 5 nm may apply, such as |λc3-λc2| ≥ 10 nm. The blueish and diffuser solid state light sources may be individually selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. Further, the optics may comprise a diffuser2025PF80043

[0014] 3

[0015] redirection optical element. Especially, the diffuser redirection optical element may be configured in an optical path between the blueish light generating device and the diffuser assembly. Additionally or alternatively, the diffuser redirection optical element may be configured in an optical path between the diffuser light generating device and the diffuser assembly. The diffuser redirection optical element may be configured to direct blueish device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly. Additionally, the diffuser redirection optical element may be configured to direct diffuser device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly. The diffuser assembly may especially comprise a diffuser configured to diffuse at least part of the blueish device light, received by the diffuser assembly via the diffuser redirection optical element, into diffused blueish device light.

[0016] Further, the diffuser may be configured to diffuse at least part of the diffuser device light, received by the diffuser assembly via the diffuser redirection optical element, into diffused diffuser device light. In embodiments, the diffuser redirection optical element may further be configured to direct the diffused blueish device light, received by the diffuser redirection optical element, into an optical path to the light exit. Additionally, the diffuser redirection optical element may be configured to direct the diffused diffuser device light, received by the diffuser redirection optical element, into an optical path to the light exit. In embodiments, (i) an optical axis of the blueish device light upstream of the diffuser redirection optical element, and (ii) an optical axis of the diffused blueish device light and the diffused diffuser device light downstream of the diffuser redirection optical element may be co-axial. Further, the light generating system may be configured such, that the blueish device light and the diffuser device light may be incident on the diffuser redirection optical element from orthogonal directions. The light generating system may be configured to generate system light.

[0017] Especially, in a first operational mode of the light generating system, the system light may comprise at least part of the diffused blueish device light and at least part of the diffused diffuser device light.

[0018] Such a light generating system may provide a reduced cost, yet high-performing system. The lower cost may be the result of minimization of the number of relatively expensive optical components. Especially, such a light generating system may facilitate diffusing the device light from multiple light generating devices using a single diffuser. Further, the invention may provide system architectures enabling operational modes, which may result in highly efficient use of installed laser diode power. Hence, the invention may enable the realization of compact and highly efficient laser-phosphor light engines that2025PF80043

[0019] 4

[0020] may comprise at least two laser sources with different spectral characteristics that may be outputted from the light generating system as a combined diffused laser light beam, wherein the combined diffused laser light beam may at least partially travel along an optical path of one of the input laser beams (such as especially the optical path of the blueish device light).

[0021] Laser-phosphor systems may require the combination of various laser light colors. Further, it may generally be needed to diffuse the laser light, both in view of an eye safety of users of the light system and in view of an irradiance limit of many optical components. For laser-phosphor systems, luminescent light may generally be combined with laser light through dichroic mixing, wherein a polarization-based splitter is used to distribute blue laser light (adjustably) over a luminescent conversion channel and a diffusion channel. In such laser-phosphor systems, a diffusion arrangement as present in the light generating system of the invention may be favorable, as it enables the mixing of at least two different laser colors while returning the diffused laser light along the same optical path as the blue laser light was incident on the diffuser assembly. The returned diffused blue laser light may especially have a polarization that is orthogonal to the incident non-diffused blue laser light. Further, a second laser color may be incident on the diffuser assembly via a different optical path, and may exit the diffuser assembly as diffused laser light combined (mixed) with the blue diffused laser light. Hence, such a light generating system may facilitate diffusing two beam (and colors) of laser light with a single diffuser arrangement, while providing diffused laser light along the same optical axis as the blue (previously divided) laser light was provided to the diffuser assembly.

[0022] The present application claims priority of the patent application bearing application number 25150896.6, filed on 9 January 2025 at the European Patent Office. Especially, the blueish light generating device as defined herein may correspond to the second light generating device of 25150896.6, with the blueish device light corresponding to the second device light, the blueish centroid wavelength (λc2) corresponding to the second centroid wavelength (λc2), the blueish solid state light source corresponding to the second solid state light source, and the diffused blueish device light corresponding to the diffused second device light. Further, the diffuser light generating device may correspond to the third light generating device of 25150896.6, with the diffuser device light corresponding to the third device light, the diffuser centroid wavelength (λc3) corresponding to the third centroid wavelength (λc3), the diffuser solid state light source corresponding to the third solid state light source, and the diffused diffuser device light corresponding to the diffused third device light. Additionally, the diffuser redirection optical element may correspond to the third2025PF80043

[0023] 5

[0024] redirection optical element of 25150896.6. Hence, for the purposes of assessing a right to priority, the term “blueish” may hereafter be read as “second”, and the term “diffuser” may hereafter be read as “third”.

[0025] In embodiments, the blueish light generating device may be configured to generate blueish device light having a blueish centroid wavelength (λc2). Especially, in embodiments, (at least part of) the blueish device light may have a blueish centroid wavelength (λc2) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. Further, in embodiments, (at least part of) the blueish device light may have a blueish centroid wavelength (λc2) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, the blueish 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. Especially, the blueish light generating device may herein be named after the color of the light produced using the blueish light generating device.

[0026] Similarly, the diffuser light generating device may be configured to generate diffuser device light (having a diffuser optical axis O3). Therefore, in embodiments, the diffuser light generating device may comprise a diffuser light source. The diffuser light source may be essentially any light source, see also further below. Especially, in embodiments, the (diffuser light source of the) diffuser light generating device may comprise a diffuser solid state light source. Hence, in embodiments, the diffuser light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode (LED). The diffuser light generating device may herein also comprise a plurality of diffuser (solid state) light sources. Especially, in specific embodiments, the diffuser light generating device may comprise a diffuser laser bank (see also above).

[0027] Further, the diffuser light generating device may be configured to generate diffuser device light having a diffuser centroid wavelength (λc3). Especially, in embodiments, (at least part of) the diffuser device light may have a centroid wavelength (λc3) selected from the wavelength range of 470-780 nm, such as from the range of 480-750 nm, like from the range of 490-700 nm, especially from the range of 500-680 nm. In specific embodiments, the diffuser centroid wavelength (λc3) may be selected from the wavelength range of 485-520 nm, i.e., the diffuser device light may be cyan light. Hence, in embodiments, the diffuser device light may be cyan, green, yellow or orange light. In specific embodiments, the diffuser device light may have a centroid wavelength (λc3) selected from the wavelength range of 570-2025PF80043

[0028] 6

[0029] 780 nm, such as from the range of 590-780 nm, like from the range of 600-750 nm. More especially, in embodiments, (at least part of) the diffuser device light may have a diffuser centroid wavelength (λc3) selected from the wavelength range of 610-700 nm, such as from the wavelength range of 620-660 nm. Hence, in embodiments, the diffuser device light may be red light. The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. Thanks to the addition of a red laser light channel, would a luminescent material be added to the light generating system, the luminescent material may be chosen to have a luminescence color point that may result in a suitable “phosphor load line” connecting the color points of the (blue) blueish device light and the luminescent light in the output (white or colored) system light to achieve improved color rendering and / or improved luminescent conversion (e.g. minimization of droop) and / or improved gamut area (e.g. using lower wavelength luminescent green emission). As a consequence, a largely improved range of CCT values may be achieved, and even a large range of color points on the black body locus (BBL) may be realized. The name “diffuser light generating device” may herein especially indicate that light generated by this light generating device may be (essentially fully) directed towards the diffuser assembly.

[0030] In embodiments, the blueish device light and the diffuser device light may have a (substantially) different centroid wavelengths. Especially, in embodiments, |λc3-λc2| ≥ 5 nm, such as |λc3-λc2| ≥ 10 nm, like |λc3-λc2| ≥ 20 nm, especially |λc3-λc2| ≥ 30 nm. Further, in embodiments, |λc3-λc2| ≥ 50 nm, such as |λc3-λc2| ≥ 100 nm, like |λc3-λc2| ≥ 150 nm. In embodiments, λc3 / λc2≥1.05. Especially, in embodiments, λc3 / λc2≥1.1, such as λc3 / λc2≥1.2, like λc3 / λc2≥1.5. However, in embodiments, λc3 / λc2≤5, such as λc3 / λc2≤4, like λc3 / λc2≤3.

[0031] In embodiments, in the first operational mode of the light generating system, the diffuser light generating device may be operated at an adjustable drive current. Therefore, in embodiments, the light generating system may comprise a control system (see also further below) configured to control (in an operational mode of the light generating system) the adjustable drive current supplied to the diffuser light generating device. Moreover, in embodiments, in an operational mode of the light generating system, the control system may be configured to (i) control the adjustable drive current supplied to the diffuser light generating device, and (ii) control (or maintain) the constant drive current supplied to the blueish light generating device. Such embodiments may be beneficial as the blueish light generating device may be operated at a constant power (or drive current) while the system may be set to any of a range of CCTs in a predetermined range of color points without2025PF80043

[0032] 7

[0033] adjusting the diffuser light generating device, where the diffuser light generating device may be operated at an adjustable drive current.

[0034] Alternatively, the diffuser light generating device may be operated at a constant drive current. In other words, a constant drive current may be supplied to the diffuser light generating device (in an operational mode of the light generating system). In embodiments, the diffuser light generating device may especially be operated at its respective rated forward current. Alternatively, in embodiments, the diffuser light generating device may especially be operated at its respective rated maximum forward current. In specific embodiments, in an operational mode the diffuser light generating device may be operated at its respective rated forward current, rated maximum forward current, or currents in between these former two. Yet, in embodiments, pulsed operation of the diffuser light generating device may be applied. Hence, in such embodiments, the diffuser light generating device may be operated at its rated peak forward current or its maximum peak forward current or currents in between these former two.

[0035] In embodiments, the blueish light generating device may be configured to provide blueish device light to the optics. The optics may, in embodiments, be configured to (re-)direct at least part of the blueish device light, received by the optics, in an optical path to the diffuser assembly. The phrase “... light received by...”, and similar phrases, such as “device light received by the optics” 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). Phrases like “a and / or b received by c” or “a and / or b reaching c”, and similar phrases may thus refer to “a received by c and / or b received by c” or “a reaching c and / or b reaching c”.

[0036] Hence, in embodiments, the blueish light generating device and the diffuser light generating device may especially be configured to provide blueish device light and diffuser device light, respectively, to the optics. In embodiments, the optics may comprise redirection optical elements. Herein, a redirection optical element may especially refer to an optical element configured to receive and redirect one or more beams of light. In particular, in embodiments, the optics (especially the redirection optical elements) may comprise (at least) a diffuser redirection optical element. Herein, the term redirection optical element may also be used to refer to a beam combiner. Note that, in embodiments, a beam combiner may also have a beam splitting functionality (see also further below). Hence, herein instead of the2025PF80043

[0037] 8

[0038] term “beam combiner” also the term “beam splitter” may be applied. In embodiments, the redirection optical element may especially be configured to (re-)direct light received by the redirection optical elements. The phrase “to direct light”, and similar phrases, in relation to (redirection) optical elements, may (a) refer to redirecting light, whereby there may be a nonzero angle (e.g. an angle of 80-100°, such as an angle of 90°) between an optical axis of the light propagating to the (redirection) optical element and an optical axis of the light emanating from the (redirection) optical element, but may (b) also refer to allowing light to pass (i.e., transmitting light), whereby there may be an angle of < 10°, such as a zero angle (i.e. parallel) between the optical axis of the light propagating to the (redirection) optical element and the optical axis of the light emanating from the (redirection) optical element. For instance, a (redirection) optical element may direct light, received by the (redirection) optical element to another optical element, whereby the redirection optical element receives light along two orthogonal (optical) paths, wherein the light from both paths may be of different types (e.g. of different polarizations, spectral power distributions, etc.), wherein one of the types of light (from one of the (optical) paths) is reflected by the (redirection) optical element to the other optical element (i.e. non-zero angle), and another one of the types of light (from the other (optical) path) is transmitted by the (redirection) optical element to the other optical element (i.e. zero angle) (and thus both are directed to that optical element). Therefore, a (redirection) optical element such as a reflector, a dichroic mirror, a polarizing beam splitter, and a lens, etc. may direct light received by such (redirection) optical element.

[0039] Especially, the term “optical axis” may be defined as an imaginary line that defines the path along which light propagates through a system starting from the light generating element, here especially one of the light generating devices. Especially, the optical axis may coincide with the direction of the light with the highest radiant flux.

[0040] Returning to the optics, in embodiments, the diffuser redirection optical element may be configured in an optical path between the blueish light generating device and the diffuser assembly. As such, the diffuser redirection optical element may be configured to direct blueish device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly. Additionally, in embodiments, the diffuser redirection optical element may be configured in an optical path between the diffuser light generating device and the diffuser assembly. As such, the diffuser redirection optical element may (also) be configured to direct diffuser device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly. In some embodiments, the blueish device light may propagate from the diffuser redirection optical element (directly) to the diffuser2025PF80043

[0041] 9

[0042] assembly (optionally via optics such as one or more integrators or lenses). In alternative embodiments, the blueish device light may propagate from the diffuser redirection optical element to the diffuser assembly via one or more further redirection optical elements and / or via an optical retarder element (e.g. an assembly polarization converter, see further below).

[0043] In embodiments, the diffuser assembly may thus be configured to receive at least part of the blueish device light (via the diffuser redirection optical element). In embodiments, the diffuser assembly may comprise (at least) a diffuser. The diffuser may, in embodiments, be configured to diffuse (or scatter) at least part of the blueish device light received by the diffuser via the diffuser redirection optical element. Especially, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the blueish device light, received by the diffuser via the diffuser redirection optical element, into diffused blueish device light.

[0044] Further, in embodiments, the diffuser light generating device and the redirection optical elements, especially the diffuser redirection optical element, may be configured to provide diffuser device light into an optical path to the diffuser assembly. Note that, in embodiments, the optical path of the diffuser device light propagating from the diffuser redirection optical element to the diffuser assembly (and from the diffuser to the light exit) may essentially be the same optical path as the optical path of the blueish device light. However, in alternative embodiments, the optical path of the diffuser device light propagating from the diffuser redirection optical element to the light exit (via the diffuser assembly) may be different from the optical path of the blueish device light (such as e.g. opposite optical paths). In some embodiments, the diffuser device light may propagate from the diffuser redirection optical element substantially directly to the diffuser assembly (optionally via optics such as one or more integrators or lenses). In alternative embodiments, the diffuser device light may propagate from the diffuser redirection optical element to the diffuser assembly via one or more further redirection optical elements and / or via an optical retarder element (such as e.g. the assembly polarization converter, see also further below). Especially, in such embodiments, the diffuser light generating device and the optics may be configured such that the diffuser device light received by the diffuser assembly may comprise linear polarized light. In some embodiments, the diffuser light generating device and the optics may be configured such that the diffuser device light received by the diffuser assembly may essentially consist of linear polarized light (such as e.g. either p-polarized light or s-polarized light). In alternative embodiments, the diffuser light generating device and the optics may be configured such that the diffuser device light received by the diffuser assembly2025PF80043

[0045] 10

[0046] may comprise linear polarized light (such as e.g. both p-polarized light and s-polarized light, or any other orientation of the polarization plane). In some embodiments, the diffuser light generating device and the optics may be configured such that the diffuser device light received by the diffuser assembly may (even) be unpolarized (or non-polarized) light.

[0047] In embodiments, the diffuser assembly may thus be configured to receive at least part of the diffuser device light. The diffuser (of the diffuser assembly) may, in embodiments, be configured to diffuse (or scatter) at least part of the diffuser device light received by the diffuser via the diffuser redirection optical element. Especially, the diffuser may be configured to diffuse at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the diffuser device light, received by the diffuser via the diffuser redirection optical element, into diffused diffuser device light.

[0048] In embodiments, the diffuser assembly may be configured in the transmissive mode or in the reflective mode. Yet further, the diffuser assembly may be configured in the collinear reflective mode or the non-collinear reflective mode. Here below, examples and further embodiments of the diffuser (assembly) will be described in more detail. In specific embodiments, the diffuser may be configured in the reflective mode (i.e. the diffuser may comprise a reflective diffuser). Therefore, in embodiments, the reflective diffuser may be (diffuse) reflective for (one or more of blueish and diffuser) device light. In embodiments, the reflective diffuser may comprise a surface diffuser, a volume diffuser, or a combination of a surface and volume diffuser. The reflective diffuser may, in embodiments, comprise one or more materials selected from the group comprising: a glass with high transmission in the spectral range of the (blueish and diffuser) device light, a silicone-based material, and a transparent ceramic material such as e.g. sapphire.

[0049] In specific embodiments, the reflective diffuser may comprise a small angle diffuser. Especially, in some embodiments, the reflective diffuser (comprising the small angle diffuser) may be configured to provide an angular spread of diffusion where as a function of a scatter angle 9, the intensity 1(9) of the diffused (or scattered) light may correspond to a function of cosn(θ), wherein n may be selected from the range of 10-100, like from the range of 20-100, such as from the range of 30-90. However, in other embodiments (when the diffuser comprises e.g. a top-hat diffuser), the reflective diffuser (comprising the small angle diffuser) may be configured to provide an angular spread of diffusion corresponding to one or more of a top-hat diffusion, or another engineered diffusion. In other words, in embodiments, the reflective diffuser may (comprise a small angle diffuser that may) be configured to redistribute incoming device light such that the diffused beam (comprising device light)2025PF80043

[0050] 11

[0051] propagating from the reflective diffuser may have a full width at half maximum (FWHM) selected from the range of 5-60°, such as from the range of 10-50°, like from the range of 10-40°, especially from the range of 12-30°. In the embodiments described here, the FWHM may especially refer to the diffused beam (comprising device light) and therefore may be the result of both the divergence of the incident beam and the diffusion by the reflective diffuser.

[0052] Further, the (reflective or transmissive) diffuser may comprise a small angle diffuser. In such embodiments, the small angle diffuser may be configured to provide an angular spread of diffusion of < 15°, such as < 10°, especially < 5°. Additionally or alternatively, the small angle diffuser may be configured to provide an angular spread of diffusion of > 1°, such as > 2°, especially > 3°. Hence, the small angle diffuser may be configured such, that a(n angular) FWHM of a diffused beam (comprising device light) propagating from the diffuser may be 1-15°, such as 2-10°, especially 3-5° larger than a(n angular) FWHM of a beam (comprising device light) propagating to the diffuser (directly upstream of the diffuser). Hence, in specific embodiments, the diffusor may comprise a small angle diffuser; wherein the small angle diffuser may be configured to provide an angular spread of diffusion of < 10°. Such an angular spread of diffusion may facilitate that the FWHM of the beam of diffused device light may be only slightly larger than the FWHM of the beam of device light upstream of the diffuser. Hence, with such a diffuser, a relatively narrow beam of diffused device light may be provided, thereby reducing the fraction of diffused device light lost at optical elements configured downstream from the diffuser.

[0053] 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 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”.

[0054] The diffuser assembly may thus comprise a reflective diffuser assembly or a transmissive diffuser assembly. When the diffuser assembly comprises a reflective diffuser assembly, the diffuser assembly may comprise a collinear diffuser assembly or a noncollinear diffuser assembly. A transmissive diffuser assembly may imply less optics or less complicated optics. A reflective diffuser assembly may be useful for safety reasons.

[0055] In specific embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of the blueish and diffuser device light reaching the diffuser and an optical axis of the diffused2025PF80043

[0056] 12

[0057] blueish and diffuser device light (diffuse and optionally specular) reflecting from the diffuser may be parallel or antiparallel, such as especially co-axial (or collinear). In other words, in embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of the blueish and diffuser device light reaching the diffuser and an optical axis of the diffused blueish and diffuser device light emanating away from the diffuser may be co-axial. Hence, in such embodiments, the diffuser may be configured in the reflective mode, such that the optical axis (Oi) of incoming (blueish and diffuser) device light and the optical axis (Or) of outgoing diffused (blueish and diffuser) device light (relative to the diffuser) may have a(n anti-)parallel (or collinear) direction relative to each other. In other words, in such embodiments, the diffuser may be configured such that a direction of incoming (blueish and diffuser) device light and a direction of outgoing diffused (blueish and diffuser) device light (relative to the diffuser) may be opposite or antiparallel. Hence, herein the term “antiparallel” in relation to optical axes may indicate that a first optical axis of a first (beam of) light and a second optical axis of a second (beam of) light may be parallel, wherein the first light may propagate along the first optical axis in a direction opposite to the direction in which the second light propagates along the second optical axis. In such embodiments, the diffuser assembly may further comprise a polarization converter. Especially, in embodiments, the polarization converter may comprise a λ / 4 waveplate. As known from the art, a waveplate or retarder is an optical device that alters the polarization state of a polarized light wave travelling through it. A halfwave plate may shift the polarization direction of linearly polarized light (especially from s to p or from p to s polarization), and a quarter-wave plate may convert linearly polarized light into elliptically (such as especially circularly) polarized light (having one of a first handedness and a second handedness, different from the first handedness) (and vice versa). The polarization converter may especially be configured between (relative to the propagation of light through the system) the diffuser redirection optical element and the diffuser.

[0058] The polarization converter may, in embodiments, be configured to convert (blueish and / or diffuser) device light received by the polarization converter comprising a linear polarization into (blueish and / or diffuser) device light having a (first) elliptical (such as especially circular) polarization. At the diffuser, in embodiments, the (blueish and / or diffuser) device light having the (first) elliptical (such as especially circular) polarization may be diffused into diffused device light having a second elliptical (such as especially circular) polarization. Therefore, in embodiments, the polarization converter may also be configured to convert diffused device light received by the polarization converter (via the diffuser) and2025PF80043

[0059] 13

[0060] having the (second) elliptical (such as especially circular) polarization into diffused device light comprising a linear polarization. For example, in embodiments, p-polarized (blueish and / or diffuser) device light may be directed by the diffuser polarization based redirection optical element to the polarization converter. In such embodiments, the polarization converter may be configured to convert the p-polarized (blueish and / or diffuser) device light into lefthanded elliptical polarized (blueish and / or diffuser) device light. Further, in such embodiments, the diffuser may be configured to diffuse the left-handed elliptical polarized (blueish and / or diffuser) device light received by the diffuser into right-handed elliptical polarized diffused device light. The polarization converter may then, in embodiments, be configured to convert the right-handed elliptical polarized diffused device light received by the polarization converter (back) to linearly polarized light, especially to s-polarized diffused device light. In another example, s-polarized (blueish) device light and p-polarized (diffuser) device light may be directed by the diffuser polarization based redirection optical element to the polarization converter. In such embodiments, the polarization converter may be configured to convert (i) the s-polarized (blueish) device light into right-handed elliptical polarized (blueish) device light, and (ii) the p-polarized (diffuser) device light into lefthanded elliptical polarized (diffuser) device light. Further, in such embodiments, the diffuser may be configured to diffuse (i) the right-handed elliptical polarized (blueish) device light received by the diffuser into left-handed elliptical polarized diffused (blueish) device light, and (ii) the left-handed elliptical polarized (diffuser) device light received by the diffuser into right-handed elliptical polarized diffused (diffuser) device light. The polarization converter may then, in embodiments, be configured to convert (i) the left-handed elliptical polarized diffused (blueish) device light received by the polarization converter (back) to linearly polarized light, especially to p-polarized diffused (blueish) device light, and (ii) the right-handed elliptical polarized diffused (diffuser) device light received by the polarization converter (back) to linearly polarized light, especially to s-polarized diffused (diffuser) device light. However, in embodiments, different polarizations and conversions from the examples described here may be possible too, such as e.g. starting from s-polarized (blueish and / or diffuser) device light, starting from p-polarized (blueish) device light and s-polarized (diffuser) device light, and / or configuring the polarization converter to convert the nondiffused p-polarized device light into right-handed elliptical polarized device light. Hence, in specific embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of the blueish and diffuser device light reaching the diffuser and an optical axis of the diffused blueish and diffuser2025PF80043

[0061] 14

[0062] device light reflecting from the diffuser may be co-axial; wherein the diffuser assembly may comprise a polarization converter configured in an optical path between the diffuser redirection optical element and the diffuser; wherein the polarization converter may be configured to convert (i) device light comprising one of the first linear polarization and a second linear polarization, different from the first linear polarization, into device light comprising an elliptical polarization, and (ii) diffused device light comprising an elliptical polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization.

[0063] In alternative embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of each of the blueish and diffuser device light reaching the diffuser and an optical axis of each of the respective diffused blueish and diffuser device light (diffuse and optionally specular) reflecting from the diffuser may not be parallel or antiparallel, especially may not be co-axial (,i.e., may be non-collinear). In other words, in embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of the blueish and diffuser device light reaching the diffuser and an optical axis of the diffused blueish and diffuser device light emanating away from the diffuser may not be coaxial. Hence, in such embodiments, the diffuser assembly may thus comprise a non-collinear diffuser assembly, wherein the diffuser may be configured in a reflective mode, such that the optical axis (Oi) of incoming device light and the optical axis (Or) of outgoing diffused device light (relative to the diffuser) may have a nonzero angle, such as an orthogonal direction, relative to each other. In such embodiments, an optical axis of incoming light may have a non-zero angle with a normal to the surface of the diffuser. Especially, a reflected beam of light may (then) also have a non-zero angle with the normal. In such embodiments, especially relative to the diffuser device light, maintenance of (linear) polarization may not be necessary (as is especially the case in the collinear configuration). Hence, in embodiments the diffuser assembly may be configured as non-collinear assembly.

[0064] In embodiments, the light generating system may be configured such that incoming device light, comprising (one or more of blueish and diffuser) device light, on the diffuser, has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser unequal to 0°, and wherein outgoing diffused device light has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser unequal to 0°, wherein the optical axes (Oi, Oo) may have a mutual angle (P) unequal to 0°. For instance, the mutual angle (P) may e.g. be selected from the range of 60-120°, such as about 90°. However, other mutual2025PF80043

[0065] 15

[0066] angles (P) may also be possible. In specific embodiments, the blueish device light received by the diffuser may have a blueish incoming optical axis (Oi2) and the diffused blueish device light reflected from the diffuser may have a blueish reflection optical axis (OR2). Hence, in embodiments where the diffuser assembly may be configured as a non-collinear assembly, the blueish incoming optical axis (Oi2) and the blueish reflection optical axis (OR2) may have a nonzero angle relative to each other. Similarly, in specific embodiments, the diffuser device light received by the diffuser may have a diffuser incoming optical axis (Oi3) and the diffused diffuser device light reflected from the diffuser may have a diffuser reflection optical axis (OR3). Hence, in embodiments where the diffuser assembly may be configured as a noncollinear assembly, the diffuser incoming optical axis (Oi3) and the diffuser reflection optical axis (OR3) may have a nonzero angle relative to each other. In some embodiments, the blueish incoming optical axis (Oi2) and the diffuser incoming optical axis (Oi3) may be parallel, especially may be essentially the same optical axis. In such embodiments, the blueish reflection optical axis (OR2) and the diffuser reflection optical axis (OR3) may also be parallel, especially may be essentially the same optical axis. In alternative embodiments, the blueish incoming optical axis (Oi2) and the diffuser incoming optical axis (Oi3) may be antiparallel, i.e., may be the same optical axis but with opposite directions. In such embodiments, the blueish reflection optical axis (OR2) and the diffuser reflection optical axis (OR3) may also be antiparallel, i.e., may be the same optical axis but with opposite directions.

[0067] Further, in such embodiments, the diffuser assembly may comprise an assembly polarization converter configured in an optical path between the diffuser redirection optical element and the diffuser assembly. Especially, in embodiments, the assembly polarization converter may be configured upstream of the (reflective) diffuser relative to blueish and / or diffuser device light. Alternatively, in embodiments, the assembly polarization converter may be configured downstream of the (reflective) diffuser relative to blueish and / or diffuser device light. In embodiments, the assembly polarization converter may comprise a birefringent rotator, especially a λ / 2 waveplate (or half waveplate). Especially, herein, in embodiments, the assembly polarization converter may be configured to convert (diffused) device light comprising one of the first linear polarization and the second linear polarization (received by the assembly polarization converter from the diffuser redirection optical element or the diffuser) into (diffused) device light comprising the other one of the first linear polarization and the second linear polarization. Especially, in embodiments, the assembly polarization converter may be configured to convert (i) (diffused) blueish (and optionally (diffused) diffuser device light) comprising the first linear polarization into, respectively,2025PF80043

[0068] 16

[0069] (diffused) blueish (and optionally (diffused) diffuser device light) comprising the second linear polarization, and (ii) (diffused) blueish (and optionally (diffused) diffuser) device light comprising the second linear polarization into, respectively, (diffused) blueish (and optionally (diffused) diffuser) device light comprising the first linear polarization. Hence, the polarization converter may be configured to convert linear polarized light received by the polarization converter and having one of the first linear polarization and the second linear polarization into device light having the other one of the first linear polarization and the second linear polarization. In specific embodiments, the assembly polarization converter may be configured to convert the polarization of the (diffused) blueish device light. Further, in embodiments, the assembly polarization converter may not convert the polarization of the (diffused) diffuser device light. Especially, in such embodiments, the diffuser redirection optical element may be transmissive for the (diffused) diffuser device light, especially device light having the diffuser centroid wavelength (λc3). However, in alternative embodiments, the assembly polarization converter may also be configured to convert the polarization of the (diffused) diffuser device light.

[0070] The diffuser assembly may further, in such embodiments, comprise a condenser optical element and a collecting optical element. In embodiments, the condenser optical element may be configured in an optical path between (i) one of the assembly polarization converter and the diffuser redirection optical element, and (ii) the diffuser. Conversely, in embodiments, the collecting optical element may be configured in an optical path between (i) the diffuser, and (ii) the other one of the assembly polarization converter and the diffuser redirection optical element. In such embodiments, the condensing and collecting (or collimating) optical elements may comprise one or more positive lenses. As it may be advantageous to create a virtual diffused device light source with dimensions that are comparable to a luminescent material light (see below), it may be preferred to apply a set of two, or possibly three positive condenser lenses to enable a large effective numerical aperture just as used in a reflective mode luminescent material configuration. For transmission efficiency as well as survival of the lenses, the induced stresses due to absorption of light may need to be limited. Especially, in embodiments, the condenser and / or collecting optical elements may comprise fused silica (FS).

[0071] The (reflective) diffuser assembly may thus comprise a diffuser, an assembly polarization converter, a condenser optical element and a collecting optical element. Further, the light generating system may, in such embodiments, comprise a plurality of reflectors. Especially, the plurality of reflectors may comprise specular (polarization maintaining)2025PF80043

[0072] 17

[0073] reflectors. The plurality of reflectors may be configured in an optical path between the diffuser redirection optical element and the diffuser. In embodiments, one or more of the plurality of reflectors may be configured to (i) reflect the blueish and diffuser device light received by the reflectors in an optical path from the diffuser redirection optical element to the diffuser assembly (optionally via the assembly polarization converter) or (ii) reflect the blueish device light received by the reflectors in an optical path from the diffuser redirection optical element to the diffuser assembly (optionally via the assembly polarization converter) and reflect the diffused diffuser device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter). Additionally or alternatively, in embodiments, one or more of the plurality of reflectors may be configured to (i) reflect the diffused blueish and diffused diffuser device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter) or (ii) reflect the diffused blueish device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter) and reflect the diffuser device light received by the reflectors in an optical path from the diffuser redirection optical element to diffuser assembly (optionally via the assembly polarization converter). Thus, in embodiments, the plurality of reflectors may be configured in an optical path, with respect to the non-diffused device light, between the diffuser redirection optical element and the diffuser assembly. Additionally or alternatively, in embodiments, the plurality of reflectors may be configured in an optical path, with respect to the diffused device light, between the diffuser redirection optical element and the diffuser assembly. Hence, in specific embodiments, the diffuser may be configured in the reflective mode, wherein the diffuser assembly may be configured such that an optical axis of the blueish and diffuser device light reaching the diffuser and an optical axis of the diffused blueish and diffuser device light reflecting from the diffuser may not be co-axial; wherein the diffuser assembly may comprise an assembly polarization converter configured in an optical path between the diffuser redirection optical element and the diffuser; wherein the assembly polarization converter may be configured to convert (i) device light comprising one of the first linear polarization and the second linear polarization into device light comprising the other one of the first linear polarization and the second linear polarization, and (ii) diffused device light comprising one of the first linear polarization and the second linear polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization; (wherein the diffuser assembly may comprise (i) a condenser2025PF80043

[0074] 18

[0075] optical element configured in an optical path between (a) one of the assembly polarization converter and the diffuser redirection optical element and (b) the diffuser and (ii) a collecting optical element configured in an optical path between (a) the diffuser and (b) the other one of the assembly polarization converter and the diffuser redirection optical element;) wherein the light generating system may comprise a plurality of reflectors configured to (i) reflect device light received from the diffuser redirection optical element in an optical path to the diffuser assembly and / or (ii) reflect diffused device light received from the diffuser in an optical path to the diffuser redirection optical element.

[0076] In embodiments, the diffuser assembly may thus comprise a non-collinear diffuser assembly, wherein the diffuser may be configured in a reflective mode, such that the optical axis (Oi) of incoming device light and the optical axis (Or) of outgoing diffused device light (relative to the diffuser) may have an angle, such as an orthogonal direction, relative to each other.

[0077] Further, in embodiments, the diffuser may comprise a static diffuser.

[0078] Alternatively, in embodiments, the diffuser may comprise a dynamic diffuser, such as e.g. a rotating wheel comprising a reflective diffuser track.

[0079] Yet, alternatively to the above described embodiments, the diffuser (assembly) may be configured in the transmissive mode. In such embodiments, the diffuser may thus be configured to diffuse (or scatter) and transmit the (blueish and / or diffuser) device light received by the diffuser. The diffuser may especially do so independently of the polarization of the device light. In addition, the transmissive diffuser may not need to preserve the polarization of the incident diffuser device light, i.e., the polarization of the diffused diffuser device light may be substantially equal to or may be substantially different from the nondiffused incident diffuser device light. Further, in such embodiments, (i.e. where the diffuser is a transmissive diffuser) the diffuser assembly may comprise the assembly polarization converter as described above (for the reflective diffuser in the non-collinear configuration). The light generating system may further, in such embodiments, comprise a plurality of reflectors. Especially, the plurality of reflectors may comprise specular (polarization maintaining) reflectors. The plurality of reflectors may be configured in an optical path between the diffuser redirection optical element and the diffuser. In embodiments, one or more of the plurality of reflectors may be configured to (i) reflect the blueish and diffuser device light received by the reflectors in an optical path from the diffuser redirection optical element to the diffuser assembly (optionally via the assembly polarization converter) or (ii) reflect the blueish device light received by the reflectors in an optical path from the diffuser2025PF80043

[0080] 19

[0081] redirection optical element to the diffuser assembly (optionally via the assembly polarization converter) and reflect the diffused diffuser device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter). Additionally or alternatively, in embodiments, one or more of the plurality of reflectors may be configured to (i) reflect the diffused blueish and diffused diffuser device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter) or (ii) reflect the diffused blueish device light received by the reflectors in an optical path from the diffuser assembly to the diffuser redirection optical element (optionally via the assembly polarization converter) and reflect the diffuser device light received by the reflectors in an optical path from the diffuser redirection optical element to the diffuser assembly (optionally via the assembly polarization converter). Thus, in embodiments, the plurality of reflectors may be configured in an optical path, with respect to the non-diffused device light, between the diffuser redirection optical element and the diffuser assembly. Additionally or alternatively, in embodiments, the plurality of reflectors may be configured in an optical path, with respect to the diffused device light, between the diffuser redirection optical element and the diffuser assembly. Hence, in embodiments, the diffuser may be configured in the transmissive mode; wherein the diffuser assembly may comprise an assembly polarization converter configured in an optical path between the diffuser redirection optical element and the diffuser; wherein the assembly polarization converter may be configured to convert (i) device light comprising one of the first linear polarization and the second linear polarization into device light comprising the other one of the first linear polarization and the second linear polarization, and (ii) diffused device light comprising one of the first linear polarization and the second linear polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization; wherein the light generating system may comprise a plurality of reflectors configured to (i) reflect device light received from the diffuser redirection optical element in an optical path to the diffuser assembly and / or (ii) reflect diffused device light emitted by the diffuser in an optical path to the diffuser redirection optical element.

[0082] Hence, in embodiments, the diffuser redirection optical element may be configured in a light-receiving relationship with the diffuser assembly. In addition to the above described, in embodiments, the diffuser redirection optical element may also be configured to direct the diffused blueish device light, received by the diffuser redirection optical element (from the diffuser assembly), into an optical path to the light exit (optionally2025PF80043

[0083] 20

[0084] via one or more further optics). Similarly, in embodiments, the diffuser redirection optical element may also be configured to direct the diffused diffuser device light, received by the diffuser redirection optical element (from the diffuser assembly), into an optical path to the light exit (optionally via one or more further optics). The diffuser redirection optical element may thus, in embodiments, be configured to redirect: (i) blueish device light (in its respective optical path to the diffuser assembly), (ii) diffuser device light (in its respective optical path to the diffuser assembly), (iii) diffused blueish device light (in an optical path to the light exit), and (iv) diffused diffuser device light (in an optical path to the light exit). To separate (e.g. in the case of the diffuser device light with the non-collinear reflective diffuser) and / or combine (e.g. in the case of the blueish device light with the collinear reflective or transmissive diffuser) the device light from the diffused device light, in embodiments, the diffuser redirection optical element may comprise a polarizing beam splitter.

[0085] A polarizing beam splitter may be considered an example of a redirection optical element. Light propagating to the polarizing beam splitter, and comprising complementary linear polarizations, like elliptically polarized light, may be split in two orthogonally propagating beams of light with complementary linear polarizations. Hence, this provides the polarizing beam splitter its beam splitting function. However, the opposite may also be true, two beams of light with complementary linear polarizations orthogonally propagating to the polarizing beam splitter may be combined in a single beam comprising both complementary linear polarizations and propagating along an axis parallel to an axis of one of the two beams of light with complementary linear polarizations orthogonally propagating to the polarizing beam splitter. Hence, for the polarizing beam splitter may apply that for a first polarization, the transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30% points higher, than for a second polarization. Similarly, for a first polarization, the reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30% points lower, than for a second polarization. Especially, in embodiments, the polarizing beam splitter may be configured to direct at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the first polarization to a first direction and at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the second polarization to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45-135°, such as about 90°. The percentage of the light may refer to a spectral power (e.g. in Watt). Especially, the first polarization and the second polarization may comprise linear polarizations such as selected from s polarization and p2025PF80043

[0086] 21

[0087] polarization. Optionally, the first polarization and the second polarization may be selected from different elliptically polarized light.

[0088] Hence, in embodiments, the diffuser redirection optical element may comprise a polarizing beam splitter. Especially, the diffuser redirection optical element may comprise a polarizing beam splitter configured to, in dependence of their respective polarizations, reflect three types of light and transmit one type of light. In such embodiments, the types of light may especially be selected from the group consisting of (i) blueish device light received by the diffuser redirection optical element from the blueish light generating device, (ii) diffused blueish device light received by the diffuser redirection optical element from the diffuser assembly, (iii) diffuser device light (in its respective optical path to the diffuser assembly) received by the diffuser redirection optical element from the diffuser light generating device, and (iv) diffused diffuser device light (in an optical path to the light exit) received by the diffuser redirection optical element from the diffuser assembly. Alternatively, in embodiments, the diffuser redirection optical element may comprise a polarizing beam splitter configured to, in dependence of their respective polarizations, transmit three (of the abovementioned) types of light and reflect one (of the abovementioned) type of light. Hence, in specific embodiments, the diffuser redirection optical element may comprise a polarizing beam splitter configured to, in dependence of their respective polarizations: (A) reflect three types of light and transmit one type of light, wherein the types of light may be selected from the group consisting of (i) blueish device light received by the diffuser redirection optical element from the blueish light generating device, (ii) diffused blueish device light received by the diffuser redirection optical element from the diffuser assembly, (iii) diffuser device light received by the diffuser redirection optical element from the diffuser light generating device, and (iv) diffused diffuser device light received by the diffuser redirection optical element from the diffuser assembly; or (B) transmit three types of light and reflect one type of light, wherein the types of light may be selected from the group consisting of (i) blueish device light received by the diffuser redirection optical element from the blueish light generating device, (ii) diffused blueish device light received by the diffuser redirection optical element from the diffuser assembly, (iii) diffuser device light received by the diffuser redirection optical element from the diffuser light generating device, and (iv) diffused diffuser device light received by the diffuser redirection optical element from the diffuser assembly.

[0089] Hence, the diffuser redirection optical element may comprise a polarizing beam splitter. Further, depending on the configuration of the light generating system,2025PF80043

[0090] 22

[0091] especially of the diffuser assembly, the diffuser redirection optical element may be configured to direct one of (a) the blueish device light and the diffused blueish device light, and (b) the diffuser device light and the diffused diffuser device light irrespective of their respective linear polarizations. That is, the diffuser redirection optical element may be a polarizing beam splitter for only one of: (a) the blueish device light and the diffused blueish device light, such as especially for (a wavelength range around) the blueish centroid wavelength (λc2), and (b) the diffuser device light and the diffused diffuser device light, such as especially for (a wavelength range around) the diffuser centroid wavelength (λc3). In such embodiments, it may not be needed to preserve a polarization of said one of the blueish device light and the diffuser device light upon diffusing said device light at the diffuser. Hence, the diffuser may not need to preserve the polarization of one of the blueish device light and the diffuser device light. Yet, for the other of the blueish device light and the diffuser device light, the diffuser may maintain the polarization of the incident light upon diffusing. Hence, the diffuser may be a polarization maintaining diffuser for one of the blueish device light and the diffuser device light. Alternatively, the diffuser may be a polarization maintaining diffuser for (both of) the blueish device light and the diffuser device light. That is, the diffuser may be a polarization maintaining diffuser for at least one of the blueish device light and the diffuser device light. In such embodiments, the light generating system may especially be configured such, that said at least one of the blueish device light and the diffuser device light, received by the diffuser redirection optical element, may comprise one of the first linear polarization and the second linear polarization. Hence, in specific embodiments, the diffuser may be a polarization maintaining diffuser for at least one of the blueish device light and the diffuser device light; wherein the light generating system may be configured such, that the at least one of the blueish device light and the diffuser device light received by the diffuser redirection optical element may comprise one of the first linear polarization and the second linear polarization.

[0092] Additionally or alternatively, the diffuser redirection optical element may comprise a multichroic beam splitter. A multichroic beam splitter may be considered an example of redirectional optics. Light propagating to the multichroic beam splitter, and comprising intensity at different spectral positions, like light having a broad spectral power distribution, or light having different spectral peaks, or like light comprising a combination of first light having a first centroid wavelength and second light having a second centroid wavelength, different from the first centroid wavelength, etc., may be split in two orthogonally propagating beams of light with different spectral power distributions. Hence,2025PF80043

[0093] 23

[0094] this provides the multichroic beam splitter its beam splitting function. However, the opposite may also be true, two beams of light with different spectral power distributions orthogonally propagating to the multichroic beam splitter may be combined in a single beam comprising both spectral power distributions and propagating along an axis parallel to an axis of one of the two beams of light with spectral power distributions orthogonally propagating to the multichroic beam splitter.

[0095] A dichroic beam splitter or beam combiner may in embodiments be configured to combine two different types of light, e.g. light having wavelengths below a predefined XI and light having wavelengths above the predefined XI. A trichroic beam splitter may in embodiments be configured combine three different types of light, e.g. in a light having a wavelength below a predefined XI and light having wavelengths above the predefined XI but below another predefined wavelength X2, and light having a wavelength above the other predefined X2. Hence, the terms “multichroic beam splitter” or “multichroic beam combiner”, or similar terms, are herein used, to indicated that in embodiments two types or more than two types of light may be combined.

[0096] Hence, for the multichroic beam splitter may apply that for a first wavelength range, the wavelength averaged transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30% points higher, than for a second wavelength range (different from the first wavelength range). Similarly, for a first wavelength range, the wavelength averaged reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30% points lower, than for a second wavelength range. Especially, in embodiments, the multichroic beam splitter may be configured to direct at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of (first) light having the first wavelength to a first direction and at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of (second) light of the second wavelength to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45-135°, such as about 90°. In embodiments, the first light may have a first centroid wavelength and the second light may have a second centroid wavelength, which may differ at least 5 nm, more especially at least about 10 nm. In embodiments the centroid wavelengths may differ at least about 15 nm. The percentage of the light may refer to a spectral power (e.g. in Watt).

[0097] Hence, the diffuser redirection optical element may comprise (a polarizing beam splitter and / or) a multichroic beam splitter. The multichroic beam splitter (of the diffuser redirection optical element) may comprise a cut-off wavelength (Xco), wherein the2025PF80043

[0098] 24

[0099] multi chroic beam splitter may be configured to reflect one of light having a wavelength above the cut-off wavelength (Xco) and light having a wavelength below the cut-off wavelength (Xco), and transmit the other of light having a wavelength above the cut-off wavelength (Xco) and light having a wavelength below the cut-off wavelength (Xco). Further, the diffuser redirection optical element may be configured to combine (or split) the (diffused) blueish device light and the (diffused) diffuser device light. Hence, in embodiments, K2 < o < Xc3 may apply, such as Ki + 2 nm < o < K3 - 2 nm, especially Ki + 5 nm < Ko < K3 - 5 nm, like Ki + 10 nm < Ko < K3 - 10 nm. Alternatively, in embodiments, K3 < Ko < K2 may apply, such as ^3 + 2 nm < Ko < Ki - 2 nm, especially K3 + 5 nm < Ko < Ki - 5 nm, like K3 + 10 nm < Ko < Ki - 10 nm. Hence, in specific embodiments, the diffuser redirection optical element may comprise a multichroic beam splitter, wherein the multichroic beam splitter may comprise a cut-off wavelength Ko), wherein one may apply of (i) Ki < Ko < K3, and (ii) K3 < Ko < Ki. A diffuser redirection optical element comprising a multichroic beam splitter may allow for more configurations of the diffuser assembly.

[0100] Hence, the diffuser redirection optical element may comprise a polarizing beam splitter and a multichroic beam splitter. In such embodiments, transmission and / or reflection of light by the diffuser redirection optical element may depend on both the wavelength and the polarization of the incident light. For instance, the multichroic beam splitter may be configured to transmit light having a wavelength below the cut-off wavelength (Ko), wherein, for this wavelength range, the polarizing beam splitter may be configured to transmit light having a first linear polarization and reflect light having a second linear polarization. Hence, in such exemplary embodiments, the diffuser redirection optical element may effectively be configured to (i) transmit light having a wavelength below the cut-off wavelength (Ko) and having the first linear polarization, (ii) reflect light having a wavelength below the cut-off wavelength (Ko) and having the second linear polarization, and (iii) reflect light having a wavelength above the cut-off wavelength (Ko).

[0101] As indicated above, the diffuser may be configured in the transmissive mode. Alternatively, the diffuser may be configured in a reflective mode, wherein the optical axis of the device light reaching the diffuser and the optical axis of the diffused device light reflecting from the diffuser may not be co-axial. In such embodiments, the blueish device light and the diffuser device light may follow the same optical path from the diffuser redirection optical element via the assembly polarization converter and the diffuser (or via the diffuser and the assembly polarization converter) back to the diffuser redirection optical element. Hence, in such embodiments, an (incoming) optical axis (Oi2) of the blueish device2025PF80043

[0102] 25

[0103] light reaching the diffuser and an (incoming) optical axis (Oi3) of the diffuser device light reaching the diffuser may be parallel(, i.e. may have the same direction). Moreover, in such embodiments, an (transmission or reflection) optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an (transmission or reflection) optical axis (Ots) of the diffused diffuser device light emanating away from the diffuser may be parallel(, i.e. may have the same direction). In other words, in such embodiments, the (incoming) optical axis (Oi2) of the blueish device light and the (incoming) optical axis (Ois) of the diffuser device light may be essentially the same optical axis. Similarly, in such embodiments, the (transmission or reflection) optical axis (Ot2) of the diffused blueish device light and the (transmission or reflection) optical axis (Ots) of the diffused diffuser device light may be essentially the same optical axis.

[0104] Alternatively, in embodiments, the blueish device light and the diffuser device light may follow (identical but) opposite optical paths from the diffuser redirection optical element back to the diffuser redirection optical element via (i) the assembly polarization converter and the diffuser, respectively, and (ii) the diffuser and the assembly polarization converter, respectively. Hence, in such embodiments, the diffuser may be configured in a transmissive mode, wherein an (incoming) optical axis (Oi2) of the blueish device light reaching the diffuser and an (incoming) optical axis (Oi3) of the diffuser device light reaching the diffuser may be antiparallel(, i.e. may be parallel, with light travelling in opposite directions along the optical axes). Moreover, in such embodiments, the diffuser may be configured in a transmissive mode, wherein an (transmission) optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an (transmission) optical axis (Ots) of the diffused diffuser device light emanating away from the diffuser may be antiparallel(, i.e. may be parallel, with light travelling in opposite directions along the optical axes). Hence, in specific embodiments, the diffuser may be configured in the transmissive mode, wherein one of the following may apply: (A) an optical axis (Oi2) of the blueish device light reaching the diffuser and an optical axis (Oi3) of the diffuser device light reaching the diffuser may be parallel; wherein an optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an optical axis (Ots) of the diffused diffuser device light emanating away from the diffuser may be parallel; and (B) an optical axis (Oi2) of the blueish device light reaching the diffuser and an optical axis (Oi3) of the diffuser device light reaching the diffuser may be antiparallel; wherein an optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an optical axis (Ot3) of the diffused diffuser device light emanating away from the diffuser may be antiparallel.2025PF80043

[0105] 26

[0106] Hence, in specific embodiments, the diffuser may be configured in the reflective mode, wherein the optical axis of the device light reaching the diffuser and the optical axis of the diffused device light reflecting from the diffuser may not be co-axial; wherein one of the following may apply: (A) an optical axis (Oi2) of the blueish device light reaching the diffuser and an optical axis (Oi3) of the diffuser device light reaching the diffuser may be parallel; wherein an optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an optical axis (Ot3) of the diffused diffuser device light emanating away from the diffuser may be parallel; and (B) an optical axis (Oi2) of the blueish device light reaching the diffuser and an optical axis (Ot3) of the diffused diffuser device light emanating away from the diffuser may be antiparallel; wherein an optical axis (Ot2) of the diffused blueish device light emanating away from the diffuser and an optical axis (Oi3) of the diffuser device light reaching the diffuser may be antiparallel.

[0107] In embodiments, the light generating system may further comprise a luminescent material. Further, the optics may further comprise a second redirection optical element. The second redirection optical element may be configured in an optical path between the blueish light generating device and the diffuser redirection optical element. Further, the second redirection optical element may be configured to direct the blueish device light, received by the second redirection optical element, into an optical path to the luminescent material and / or into an optical path to the diffuser assembly. The second redirection optical element may especially do so in dependence of the linear polarization of the blueish device light. Especially, the second redirection optical element may be configured to direct at least part of the blueish device light (e.g. a part comprising a first linear polarization), received by the second redirection optical element, into an optical path to the luminescent material. Additionally or alternatively, the second redirection optical element may be configured to direct at least (another) part of the blueish device light (e.g. a part comprising a second linear polarization, different from the first linear polarization), received by the second redirection optical element, into an optical path to the diffuser assembly. The second redirection optical element may especially do so in dependence of the (linear) polarization of light received by the second redirection optical element.

[0108] Hence, in embodiments, the second redirection optical element may comprise a polarization-based redirection optical element, i.e., may comprise a polarizing beam splitter (PBS). In embodiments, via polarization multiplexing, device light from different light generating devices but propagating along the same optical path or along the same direction, may be split into different optical paths provided that they differ in (linear) polarization.2025PF80043

[0109] 27

[0110] Further, a polarizing beam splitter or beam combiner may, in embodiments, be configured combine two different types of light, e.g. in a light having a first (linear) polarization and light having a second (linear) polarization, different from the first (linear) polarization.

[0111] Hence, the terms “polarizing beam splitter” or “polarizing beam combiner”, or similar terms, are herein used, to indicated that in embodiments two types or more than two types of light may be combined. With a polarizing beam combiner, separate beams of light having different (linear) polarization may be “multiplexed” (i.e. combined). For instance, a light beam comprising both s-polarized light and p-polarized light may be split into different optical paths; or a light beam comprising elliptically polarized light comprising relatively more p-polarization than s-polarization, and a light beam comprising elliptically polarized light comprising relatively more s-polarization than p-polarization may be (at least partially) combined with a polarization-based redirection optical element (which may also be indicated as polarizing beam combiner or polarizing beam splitter).

[0112] In embodiments, the second redirection optical element may (thus) comprise a polarizing beam splitter. Therefore, in embodiments, the device light reaching the second redirection optical element may comprise polarized light. Especially, in embodiments, the light generating system may be configured such that the blueish device light reaching the second redirection optical element may comprise a controllable (linear) polarization.

[0113] Therefore, in embodiments, the light generating system may comprise the control system as described above. Moreover, in embodiments, the light generating system may comprise a polarization control system. The polarization control system may, in embodiments, be configured to control the polarization of the blueish device light reaching the second redirection optical element. Hence, in embodiments the polarization control system may be configured to control the polarization of the blueish device light (reaching the second redirection optical element). The polarization control system may especially be configured to provide, in an optical path to the second redirection optical element, an adjustable contribution of (a) blueish device light comprising a first linear polarization and (b) blueish device light comprising a second linear polarization different from the first linear polarization. Especially, in embodiments, the polarization control system may be configured to control an adjustable intensity (or power) contribution of (i) (a first part of) the blueish device light comprising the first linear polarization and (ii) (a second part of) the blueish device light comprising the second linear polarization directed to the second redirection optical element relative to the total (or summed) intensity (or power) of the blueish device light. As such, the (blue) optical power provided to the luminescent material versus the (blue)2025PF80043

[0114] 28

[0115] optical power provided to the diffuser assembly may be controlled. The polarization control system may be configured to control an adjustable intensity (or power) contribution of the blueish device light directed to the luminescent material (and / or to the diffuser assembly) in embodiments where the polarization control system comprises one or more of (i) a movement element configured to rotate the blueish light generating device, and (ii) a first (optical) retarder element configured in an optical path between the blueish light generating device and the second redirection optical element. The first (optical) retarder element and the movement element are described in more detail further below.

[0116] In embodiments, the adjustable intensity (and / or power) contribution may be selected from the range of 0% of the blueish device light comprising the first linear polarization (and thus 100% of the blueish device light comprising the second linear polarization) directed to the second redirection optical element, to 100% of the blueish device light comprising the first linear polarization (and thus 0% the blueish device light comprising the second linear polarization) directed to the second redirection optical element. Conversely, in embodiments, the adjustable intensity (and / or power) contribution may be selected from the range of 0% of the blueish device light comprising the second linear polarization (and thus 100% of the blueish device light comprising the first linear polarization) directed to the second redirection optical element, to 100% of the blueish device light comprising the second linear polarization (and thus 0% the blueish device light comprising the first linear polarization) directed to the second redirection optical element. For example, in embodiments, the contribution of the blueish device light comprising the first linear polarization (to the second redirection optical element) may be 20%, whereas the contribution of the blueish device light comprising the second linear polarization (to the second redirection optical element) may be 80%. In another example, those contributions may be 30% and 70%, 40% and 60%, or vice versa. In specific embodiments, the contribution of the blueish device light comprising the first linear polarization (to the second redirection optical element) and the contribution of the blueish device light comprising the second linear polarization (to the second redirection optical element) may both be 50%.

[0117] Hence, in embodiments, the polarization control system may be configured to control the polarization of the blueish device light reaching the second redirection optical element. The control system may further be configured to control the polarization control system. As such, in embodiments, the control system may be configured to control one or more of a spectral power distribution, a correlated color temperature, a color gamut, and a color rendering index (CRI) of the system light by controlling the polarization control2025PF80043

[0118] 29

[0119] system. Additionally or alternatively, in embodiments, the control system may be configured to control one or more of a spectral power distribution, a correlated color temperature, a color gamut, and a color rendering index of the system light by controlling the adjustable drive current of the diffuser light generating device.

[0120] In embodiments, the polarization control system may comprise one or more of the first (optical) retarder element (like a first optical retarder plate) and the movement element. The first retarder element may be configured in an optical path between the blueish light generating device and the second redirection optical element. Further, in embodiments, the (first) retarder element may be configured to dictate the polarization of light propagating from the retarder element. Especially, in embodiments, the (first) retarder element may be configured to change the polarization of device light received by the retarder element in dependence of the orientation of the retarder element. Therefore, in embodiments, the (first) retarder element may comprise one or more of a birefringent rotator such as a X / 2 waveplate or a λ / 4 waveplate, a liquid crystal polarization rotator, a Faraday rotator, a Fresnel rhomb, and a diffractive waveplate. Especially, in embodiments, the first retarder element may comprise a λ / 2 waveplate (with respect to the blueish centroid wavelength). However, in embodiments, other types of birefringent rotators (such as e.g. a λ / 4 waveplate) may herein not be excluded.

[0121] The movement element may, in embodiments, be configured to (move, especially) rotate (at least) the blueish light generating device (about its optical axis (O2)). Additionally or alternatively, in embodiments, the movement element may be configured to rotate one or more other light generating devices (such as the diffuser light generating device, about its optical axis (O3)). Therefore, in embodiments, the movement element may e.g. comprise an actuator. In embodiments, the control system may be configured to control the polarization control system. As such, in embodiments, the control system may be configured to control (movement, especially) rotation of the light generating device(s) by controlling the movement element. By changing the orientation of the light generating devices relative to downstream configured optics (such as e.g. the second redirection optical element), the polarization of said device light propagating to the receiving optics (such as propagating to the second redirection optical element) may change.

[0122] Note that, in embodiments, the orientations of the retarder element and / or the light generating devices as described above may also be factory set and fixated by a fixating means (such as e.g. a screw). Hence, in specific embodiments, the light generating system may be configured such that the blueish device light reaching the second redirection optical2025PF80043

[0123] 30

[0124] element may comprise a controllable polarization; wherein the light generating system may comprise a control system and a polarization control system; wherein the polarization control system may be configured to control the polarization of the blueish device light reaching the second redirection optical element; and wherein the control system may be configured to control one or more of a spectral power distribution, a correlated color temperature, a color gamut, and a color rendering index of the system light by controlling the polarization control system. Further, in specific embodiments, the polarization control system may comprise one or more of (A) a first retarder element configured in an optical path between the blueish light generating device and the second redirection optical element, wherein the control system may be configured to control rotation of the first retarder element; and wherein the first retarder element may comprise a λ / 2 waveplate; and (B) a movement element configured to rotate the blueish light generating device; and wherein the control system may be configured to control the movement element.

[0125] The polarization control system may thus be configured to control an intensity (or power) contribution of blueish device light being directed to the luminescent material and directed to the diffuser assembly by controlling the polarization of the blueish device light. In some embodiments, the (blueish) device light (reaching the second redirection optical element) may comprise both the first linear polarization and the second linear polarization, i.e., the device light may comprise a first part and a second part comprising the first linear polarization and the second linear polarization, respectively. Especially, in embodiments, (at least) the blueish device light (received by the second redirection optical element) may comprise a first part of the blueish device light comprising the first linear polarization (e.g. p-polarization) and a second part of the blueish device light comprising the second linear polarization (e.g. s-polarization). In the extreme, the (blueish) device light (reaching the second redirection optical element) may essentially consist of device light comprising the first linear polarization (e.g. p-polarization), and may thus comprise essentially no device light comprising the second linear polarization (e.g. s-polarization), or vice versa.

[0126] Alternatively, in embodiments, the (blueish) device light (reaching the second redirection optical element) may comprise 90% p-polarized light and 10% s-polarized light, or 80% p-polarized light and 20% s-polarized light, or vice versa. In another example, the (blueish) device light (reaching the second redirection optical element) may comprise 70% p-polarized light and 30% s-polarized light, or 60% p-polarized light and 40% s-polarized light, or vice versa. Yet in another example, the (blueish) device light (reaching the second redirection optical element) may comprise 50% p-polarized light and 50% s-polarized light.2025PF80043

[0127] 31

[0128] In embodiments, the luminescent material may thus be configured in a lightreceiving relationship with the second redirection optical element. In embodiments, the luminescent material may be configured to convert at least part of the (blueish) 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 device light (especially the part of the blueish device light) received by the luminescent material into luminescent material light. Further, the luminescent material may be configured to convert at least 95%, especially at least 98%, including essentially 100% of the device light (especially the part of the blueish 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 device light (especially the part of the blueish device light) received by the luminescent material into luminescent material light.

[0129] The terms “visible light” or “visible emission”, and similar terms, refer to light having one or more wavelengths in the range of about 380-780 nm. The term “luminescent material” may also refer to a plurality of different luminescent materials, such as a luminescent material composition. Instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art. Examples of luminescent materials are indicated below.

[0130] In embodiments, luminescent materials may be selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium. In embodiments, the luminescent material may comprise a divalent europium comprising oxynitride luminescent material. Further, in embodiments, the luminescent material may comprise a divalent europium comprising nitride luminescent material.

[0131] In embodiments, the luminescent material may comprise a luminescent material of the type A3B5O12:Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc; and wherein the light source light may comprise blue light source light (i.e., a cerium comprising garnet material). Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Further, B may comprise one or more of Al and Ga, such as at least Al, especially entirely Al. The term “: Ce”, indicates that part of the metal ions (i.e. in the garnets part of the “A” ions)2025PF80043

[0132] 32

[0133] in the luminescent material is replaced by Ce, as is known to the person skilled in the art. Ce may replace A for < 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0134] In embodiments, the luminescent material may comprise a luminescent material of the type A3Si6N11:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y. Alternatively or additionally, the luminescent material may comprise one or more of MS:Eu2+, M2Si5N8:Eu2+, MAlSiN3:Eu2+, Ca2AlSi3O2N5:Eu2+, etc., wherein M comprises one or more of Ba, Sr and Ca, such as 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, as is known to the person skilled in the art. In general, Eu may be present in amounts of < 10% of the cation, such as in the range of 0.5-10%, especially in the range of 0.5-5% relative to the cation(s) it replaces. The term “: Eu”, indicates that part of the metal ions (indicated by M) is replaced by Eu.

[0135] The term “luminescent material” herein especially relates to inorganic luminescent materials. Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc.

[0136] In embodiments, the luminescent material may comprise a luminescent material of the type M1-xLi3-2yAl1+2y-zSizO4-4y-zN4y+z:Eux. Herein, M may comprise one or more of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba), such as especially one or more of Ca, Sr, and Ba. Hence, M1-xLi3-2yAl1+2y-zSizO4-4y-zN4y+z:Euxmay especially refer to (Mg, Ca, Sr, Ba)i-xLi3-2yAli+2y-zSizO4-4y-zN4y+z: Eux. Such a luminescent material may be indicated as an SLA-type phosphor, or SLA phosphor. SLA phosphors may be described in US2021171827A1, which is hereby herein incorporated by reference.

[0137] Further, the luminescent material may comprise a (divalent europium comprising) SiAlON phosphor, such as selected from the group comprising (a) Si12-m-nAlm+nOnN16-n:Eu2+(a-Si A1ON), (b) Si6-nAlnOnN8-n:Eu2+, wherein 0 < n < 4.2 (P-SiAlON), and (c) Si2-nAlnO1+nN2-n:Eu2+, wherein 0 < n < 0.2 (O-SiAlON).

[0138] In embodiments, the luminescent material may comprise a tetravalent manganese-comprising luminescent material, i.e., a luminescent material doped with tetravalent manganese (Mn4+). Especially, in embodiments, the luminescent material may2025PF80043

[0139] 33

[0140] comprise a luminescent material of the type M’xM2-2xAX6 doped with Mn4+, wherein M’ comprises an alkaline earth cation, M comprises an alkaline cation, and x may be selected from the range of 0-1, wherein A comprises a tetravalent cation, e.g. comprising one or more of silicon and titanium, and wherein X comprises a monovalent anion, at least comprising fluorine. Such luminescent materials may herein also be indicated as “KSiF” or “KSF”, regardless of the composition of M’, M, A, and X. In specific embodiments, the indication M’XM2-2XAX6 may refer to one or more of (K, Rb)2SiFe: Mn4+, (K, Rb)2TiFe: Mn4+, K2(Si, Ti)Fe: Mn4+, and Rb2(Si, Ti)Fe: Mn4+, such as one or more of K2TiFe: Mn4+, of K2SiFe: Mn4+, and of Rb2SiFe: Mn4+. As can be derived from the above, “(Si, Ti)” may indicate one or more of Si and Ti. Hence, in specific embodiments, the luminescent material may comprise one or more of (K,Rb)2SiF6:Mn4+and K2(Si,Ti)F6:Mn4+.

[0141] Furthermore, in embodiments, the luminescent material light and the diffuser device light may have a different centroid wavelength (e.g. the diffuser centroid wavelength (λc3) may be larger than the luminescent material centroid wavelength ( imc)). Especially, |λc3-λlmc| ≥ 5 nm may apply, such as |λc3-λlmc| ≥ 10 nm, especially |λc3-λlmc| ≥ 20 nm. Such embodiments may be beneficial as the different centroid wavelengths may facilitate easier multi chroic requirements of optical elements applied for multi chroic multiplexing (i.e. multichroic -based redirection optical elements). Especially, in embodiments, λc3-λlmc≥ 5 nm may apply, such as λc3-λlmc≥ 10 nm, especially λc3-λlmc≥ 20 nm.

[0142] Alternatively, in embodiments, the diffuser centroid wavelength (λc3) may be larger than the blueish centroid wavelength (λc2) and smaller than the luminescent material centroid wavelength ( imc). Hence, in such embodiments, λc2≤ λc3≤ λlmc, like λc2< λc3< λlmc.

[0143] In embodiments, the luminescent material may be configured in the reflective mode. In general, the luminescent material may give rise to quite a lot of thermal dissipation. 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. Especially, 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. A rotating wheel may enable significant spreading of thermally dissipated power over a larger surface area than static modes of operation.

[0144] Similarly, as indicated above, the (reflective) diffuser assembly may generate heat which may be detrimental to the (efficiency of the) light generating system. Therefore, in embodiments, the light generating system may comprise a rotating element, such as e.g. a2025PF80043

[0145] 34

[0146] phosphor wheel or a phosphor rod. In such embodiments, one or more of the luminescent material and the diffuser may be configured on the rotating element, such as especially at least the luminescent material. Hence, in embodiments, the light generating system may comprise a rotating element, wherein one or more of (a) the luminescent material and (b) the diffuser may be configured on the rotating element; and wherein said one or more of (a) the luminescent material and (b) the diffuser may optionally be configured in the reflective mode.

[0147] In embodiments wherein (both) the luminescent material and the diffuser may be configured on the rotating element, the diffuser may especially be configured closer to an axis of rotation of the rotating element than the luminescent converter. That is, would the rotating element be a phosphor wheel, (a ring of) the diffuser may have a smaller radius on the rotating element than (a ring of) the luminescent material (wherein the rings of the diffuser and the luminescent material may be concentric around the axis of rotation).

[0148] Alternatively, would the diffuser and luminescent material be configured on separate rotating elements, the rotating element comprising the diffuser may especially have a smaller diameter (perpendicular to an axis of rotation of the rotating element) than the rotating element comprising the luminescent converter.

[0149] 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. Note that, in embodiments, the thermally conductive element may nonetheless comprise a rotating element, such as a phosphor wheel or a phosphor rod. Hence, in embodiments where the luminescent material may be configured in the transmissive mode, the luminescent material may also be configured on a rotating element.

[0150] 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 < 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 distance between two respective surfaces of the respective2025PF80043

[0151] 35

[0152] elements. The distance may be an average distance. When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum.

[0153] A thermally conductive element may especially comprise a thermally conductive material. A thermally conductive material may especially have a thermal conductivity of > 10 W / (m*K), such as > 20 W / (m*K), like > 30 W / (m*K), such as > 100 W / (m*K), like especially > 200 W / (m*K).

[0154] In a first operational mode of the light generating system, the system light may comprise (at least part of) the luminescent material light, (at least part of) the diffused blueish device light, and (at least part of) the diffused diffuser device light. In such a first operational mode, the system light may especially be white light. The term “white light”, and similar terms, herein, is known to the person skilled in the art. It may especially relate to light having a correlated color temperature (CCT) between 1800 K and 20000 K, such as between 2000 and 20000 K, especially between 2700-20000 K, for general lighting especially in the range of 2000-7000 K, such as in the range of 2700-6500 K. In specific embodiments, the CCT may be selected from the range of 2700-6500 K, in combination with a color rendering index (CRI) of at least 75, such as at least 80. In embodiments, in an operational mode of the light generating system, the system light may be white light having a color rendering index of at least 75, such as at least 80, like at least 85, especially at least 90. To achieve white light having such CCT and CRI ranges, the addition of the red diffuser device light as described in this invention may be especially beneficial because of inadequate red spectral contributions in high brightness luminescent material light.

[0155] In specific embodiments, the light generating system may further comprise a luminescent material; wherein the optics may further comprise a second redirection optical element; wherein: (A) the second redirection optical element may be configured in an optical path between the blueish light generating device and the diffuser redirection optical element; wherein the second redirection optical element may comprise a polarizing beam splitter; wherein the second redirection optical element may be configured to direct the blueish device light, received by the second redirection optical element, into an optical path to the luminescent material and / or the diffuser assembly in dependence of its linear polarization; (B) the luminescent material may be configured to convert at least part of the blueish device light, received by the luminescent material via the second redirection optical element, into luminescent material light, wherein the luminescent material light may have a luminescent2025PF80043

[0156] 36

[0157] material centroid wavelength (λlmc), wherein |λc3-λlmc| ≥ 10 nm; and (C) in a first operational mode of the light generating system, the system light may be white light comprising at least part of the luminescent material light, at least part of the diffused blueish device light, and at least part of the diffused diffuser device light. Such a light generating system, and such an operational mode, may provide the benefit that the light generating system may be used in (general) lighting applications requiring white light. Further, with such a light generating system, the ratio between diffused blueish device light and luminescent material light in the system light may be adjusted by adjusting a polarization (state) of the blueish device light received by the second redirection optical element.

[0158] In embodiments, the second redirection optical element may further be configured in a light-receiving relationship with the diffuser redirection optical element. Especially, the second redirection optical element may be configured in an optical path between the diffuser redirection optical element and the light exit. Additionally, in embodiments, the second redirection optical element may be configured in a light-receiving relationship with the luminescent material. As such, in embodiments, the second redirection optical element may further be configured to direct the luminescent material light, the diffused blueish device light, and the diffused diffuser device light, received by the second redirection optical element, into an optical path to the light exit. In such embodiments, the luminescent material centroid wavelength (λlmc) may especially be selected from the range of 490-620 nm, such as from the range of 500-600 nm, like from the range of 520-590 nm.

[0159] Therefore, in embodiments, the second redirection optical element may further comprise a multichroic beam combiner. In embodiments, the multichroic -based redirection optical element may essentially comprise a spectral filter, such as e.g. a high-pass spectral filter, a low-pass spectral filter, or a combination thereof (also referred to as a band-pass or band-block filter). Further, in embodiments, the multichroic -based redirection optical element may comprise a combination of two or more of a high-pass, a low-pass, a band pass, and a band block filter. Note that therein, the term “multichroic beam combiner” may refer to a multichroic (or spectral) filter as described above, i.e., having one or more cut-off wavelengths. However, herein the term “multichroic beam combiner” may also refer to a combination of an optical component, such as e.g. a polarizing beam splitter, with further spectral requirements. For example, in embodiments, the second redirection optical element may comprise (i) a polarizing beam splitter having PBS-functionality for blue (or red) light combined with (ii) transmissive properties for yellow-green and reflective properties for red (or blue) light (referred to as multichroic beam combiner). Note that, in such embodiments,2025PF80043

[0160] 37

[0161] the spectral requirements imposed by the multichroic beam combiner may apply to (only) one of the (linear) polarizations, but not for its complementary (e.g. orthogonal linear) polarization. Herein, such a component comprising a combination of an optical component, such as e.g. a polarizing beam splitter, with further spectral requirements may be described as a combined polarizing beam splitter and multichroic beam combiner.

[0162] Nonetheless, the multichroic beam combiner (of the second redirection optical element) may comprise a first cut-off wavelength (Xcoi). Additionally or alternatively, the multichroic beam combiner may comprise a second cut-off wavelength (λco2). Additionally, in embodiments, the multichroic beam combiner may comprise a third cut-off wavelength (Xcos). The first cut-off wavelength (λco1) may especially be selected from the range of λc2+ 5 nm < λco1< λlmc- 10 nm. For example, the first cut-off wavelength (Xcoi) may be selected from the range of 435-590 nm, such as from the range of 445-570 nm, like from the range of 455-550 nm. Further, in embodiments, the first cut-off wavelength (Xcoi) may be selected from the range of 440-480 nm, like from the range of 445-475 nm. In embodiments, the multichroic beam combiner may comprise a low-pass filter, i.e., light having a wavelength below the first cut-off wavelength (Xcoi) may be transmitted, whereas light having a wavelength above the first cut-off wavelength (Xcoi) may be reflected. Hence, in embodiments, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element and having a wavelength below the first cut-off wavelength (Xcoi) and reflect light received by the second redirection optical element and having a wavelength above the first cut-off wavelength (Xcoi), wherein λc2+ 5 nm < λco1< λlmc- 10 nm. For example, in embodiments, the multichroic beam combiner may be configured to (i) transmit (diffused) blueish device light and diffused diffuser device light (received by the multichroic beam combiner) (especially where %3 is selected from the range of 485-520 nm) and (ii) reflect luminescent material light (received by the multichroic beam combiner).

[0163] Additionally or alternatively, the multichroic beam combiner may comprise a high-pass filter, i.e., light having a wavelength above the first cut-off wavelength (Xcoi) may be transmitted, whereas (at least a part of) light having a wavelength below the first cut-off wavelength (Xcoi) may be reflected. In such embodiments, at least a part of the blueish device light (i.e. device light having the second centroid wavelength (X^)) may be transmitted by the multichroic beam splitter. For example, in embodiments, > 5% of the device light having a wavelength below the first cut-off wavelength ( coi) may be transmitted, such as > 10%, especially > 15%. Further, in embodiments, < 50% of the device light having a wavelength2025PF80043

[0164] 38

[0165] below the first cut-off wavelength (Xcoi) may be transmitted, such as < 40%, especially < 30%. Such embodiments may allow (blue) device light to propagate both to the luminescent converter channel of the light generating system and the diffuser channel of the light generating system. Hence, in embodiments, the multichroic beam combiner may be configured to reflect (a part of) light received by the second redirection optical element and having a wavelength below the first cut-off wavelength (Xcoi) and transmit light received by the second redirection optical element and having a wavelength above the first cut-off wavelength (Xcoi), wherein λc2+ 5 nm < λco1< λlmc- 10 nm. For example, the multichroic beam combiner may be configured to (i) transmit blueish device light (received by the multichroic beam combiner) in an optical path to the diffuser assembly, (ii) transmit luminescent material light (received by the multichroic beam combiner) in an optical path to the light exit, (iii) reflect diffused blueish device light (received by the multichroic beam combiner) in an optical path to the light exit, and (iv) reflect diffused diffuser device light (received by the multichroic beam combiner) in an optical path to the light exit (especially wherein %3 is selected from the range of 485-520 nm).

[0166] The second cut-off wavelength (λco2) may especially be selected from the range of λlmc+ 10 nm < λco2< λc3- 5 nm. For example, in embodiments, the second cut-off wavelength (Xco2) may be selected from the range of 510-775 nm, such as from the range of 550-715 nm, like from the range of 610-695 nm. Further, in embodiments, the second cut-off wavelength (Xco2) may be selected from the range of 600-680 nm, like from the range of 620-635 nm. In embodiments, the multichroic beam combiner may comprise a low-pass filter. Hence, in embodiments, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element and having a wavelength below a second cut-off wavelength (Xco2) and reflect light received by the second redirection optical element and having a wavelength above the second cut-off wavelength (Xco2), wherein λlmc+ 10 nm < λco2< λc3- 5 nm. For example, the multichroic beam combiner may be configured to (i) transmit blueish (diffused) device light and (most of the) luminescent material light (received by the multichroic beam combiner), and (ii) reflect (diffused) diffuser device light (received by the multichroic beam combiner).

[0167] Additionally or alternatively, the multichroic beam combiner may comprise a high-pass filter, i.e., light having a wavelength above the second cut-off wavelength (Xco2) may be transmitted, whereas (at least a part of) light received by the second redirection optical element and having a wavelength below the second cut-off wavelength (Xco2) may be reflected. In such embodiments, at least a part of the blueish device light (i.e. device light2025PF80043

[0168] 39

[0169] having the blueish centroid wavelength (λc2)) may be transmitted by the multichroic beam splitter, see also further above. Hence, in embodiments, the multichroic beam combiner may be configured to reflect (at least a part of) light received by the second redirection optical element and having a wavelength below the second cut-off wavelength (>^<>2) and transmit light received by the second redirection optical element and having a wavelength above the second cut-off wavelength (Xco2), wherein λlmc+ 10 nm < λco2< λc3- 5 nm. For example, the multichroic beam combiner may be configured to (i) reflect (diffused) blueish device light and (most of the) luminescent material light (received by the multichroic beam combiner) and (ii) transmit (diffused) diffuser device light (received by the multichroic beam combiner).

[0170] Yet, in embodiments, the multichroic beam combiner may comprise both the first cut-off wavelength (Xcoi) and the second cut-off wavelength (X^). In such embodiments, the second cut-off wavelength (Xco2) may be higher than the first cut-off wavelength (Xcoi), i.e., λco2> λco1. Especially, in such embodiments, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element and having a wavelength below a first cut-off wavelength (Xcoi) and above a second cut-off wavelength ( co2) and reflect light received by the second redirection optical element and having a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2), wherein λc2+ 5 nm < λco1< λlmc- 10 nm and kimc + 10 nm < >^<>2 < 3 - 5 nm. For example, the multichroic beam combiner may be configured to (i) transmit (diffused) blueish device light and (diffused) diffuser device light (received by the multichroic beam combiner) and (ii) reflect luminescent material light (received by the multichroic beam combiner).

[0171] Hence, in embodiments, the multichroic beam combiner may comprise a combination of filters which may also be referred to as a band-reflection (or band-block) filter.

[0172] Conversely, in embodiments, the multichroic beam combiner may be configured to reflect (at least a part of) light received by the second redirection optical element and having a wavelength below a first cut-off wavelength (Xcoi), reflect light having a wavelength above a second cut-off wavelength (Xco2), and transmit light received by the second redirection optical element and having a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2), wherein λc2+ 5 nm < λco1< λlmc- 10 nm and λlmc+ 10 nm < λco2< λc3- 5 nm. In such embodiments, at least a part of the blueish device light (i.e. device light having the blueish centroid wavelength (λc2)) may be transmitted by the multichroic beam splitter, see also further above. For example, the multichroic beam combiner may be configured to (i) reflect (diffused) blueish device light and (diffused) diffuser device light (received by the multichroic beam combiner) and (ii)2025PF80043

[0173] 40

[0174] transmit luminescent material light (received by the multichroic beam combiner). Hence, in embodiments, the multichroic beam combiner may comprise a combination of filters which may also be referred to as a band-pass (or band-transmission) filter. Such embodiments, and embodiments wherein the multichroic beam combiner may comprise a band-reflection (or band-block) filter, may be beneficial as it may, in case the second redirection optical element comprises a combined multichroic beam combiner with a polarizing beam splitter, reduce luminescent material light output loss in case of spectral overlap of the third device light with the luminescent material light.

[0175] The third cut-off wavelength (λco3) may especially be selected from the range of λco3> λc3+ 5 nm. For example, in embodiments, the third cut-off wavelength (>^<>3) may be selected from the range of 595-775 nm, such as from the range of 600-750 nm, like from the range of 610-720 nm. Further, in embodiments, the third cut-off wavelength (Xco3) may be selected from the range of 615-735 nm, like from the range of 635-700 nm. In embodiments, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element and having a wavelength below a second cut-off wavelength (λco2) and above a third cut-off wavelength (λco3), and reflect light received by the second redirection optical element and having a wavelength between the second cut-off wavelength (kco2) and the third cut-off wavelength (Xco3), wherein imc +

[0176]

[0177] 10 nm < Ac<>2 < - 5 nm and Xco3 > kc3 + 5 nm. Hence, the multichroic beam combiner may comprise a combination of filters which may also be referred to as a band-block filter. For example, the multichroic beam combiner may be configured to (i) transmit (diffused) blueish device light and (most of the) luminescent material light (received by the multichroic beam combiner) and (ii) reflect (diffused) diffuser device light (received by the multichroic beam combiner).

[0178] Alternatively, the multichroic beam combiner may be configured to reflect (at least a part of) light received by the second redirection optical element and having a wavelength below the second cut-off wavelength (Xco2), reflect light received by the second redirection optical element and having a wavelength above the third cut-off wavelength (Xco3), and transmit light received by the second redirection optical element and having a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xco3). In such embodiments, at least a part of the blueish device light (i.e. device light having the blueish centroid wavelength (λc2)) may be transmitted by the multichroic beam splitter, see also further above. For example, the multichroic beam combiner may be configured to (i) reflect (diffused) blueish device light and (most of the) luminescent material light (received by the multichroic beam combiner) and (ii) transmit (diffused) diffuser device light (received2025PF80043

[0179] 41

[0180] by the multichroic beam combiner). Hence, in embodiments, the multichroic beam combiner may be configured to reflect light having a wavelength below a second cut-off wavelength (λco2) and above a third cut-off wavelength (λco3) and transmit light having a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xcos), wherein imc + 10 nm < Xco2 < Xc3 - 5 nm and Xc<>3 > 3 + 5 nm.

[0181] In some embodiments, the multichroic beam combiner may comprise the first cut-off wavelength (Xcoi), the second cut-off wavelength (Xco2), and the third cut-off wavelength (Xco3). In such embodiments, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element and having a wavelength below a first cut-off wavelength (Xcoi) and between a second cut-off wavelength (Xco2) and a third cut-off wavelength ( 03) and reflect light received by the second redirection optical element and having a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xcos), wherein + 5 nm < coi < imc - 10 nm, Ximc + 10 nm < Xc<>2 < 3 - 5 nm and Xc<>3 > 3 + 5 nm. For example, the multichroic beam combiner may be configured to (i) transmit blueish (diffused) device light and (diffused) diffuser device light (received by the multichroic beam combiner) and (ii) reflect (most of the) luminescent material light (received by the multichroic beam combiner).

[0182] Conversely, in embodiments, the multichroic beam combiner may be configured to reflect (at least a part of) light received by the second redirection optical element and having a wavelength below a first cut-off wavelength (Xcoi), reflect light received by the second redirection optical element and having a wavelength between a second cut-off wavelength (Xco2) a third cut-off wavelength (Xcos), transmit light received by the second redirection optical element and having a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xcos), wherein z + 5 nm < Xcoi < |mc- 10 nm, X|mc+ 10 nm < Xc<>2 < 3 - 5 nm and Xco3 > Xc3 + 5 nm. In such embodiments, at least a part of the blueish device light (i.e. device light having the blueish centroid wavelength (λc2)) may be transmitted by the multichroic beam splitter, see also further above. For example, the multichroic beam combiner may be configured to (i) reflect (diffused) blueish device light and (diffused) diffuser device light (received by the multichroic beam combiner) and (ii) transmit (most of the) luminescent material light (received by the multichroic beam combiner).

[0183] Hence, in specific embodiments, the second redirection optical element may be configured in an optical path between the diffuser redirection optical element and the light exit; wherein the second redirection optical element may be configured to direct the2025PF80043

[0184] 42

[0185] luminescent material light, the diffused blueish device light, and the diffused diffuser device light, received by the second redirection optical element, into an optical path to the light exit; wherein the luminescent material centroid wavelength ( imc) may be selected from the range of 500-600 nm; wherein the second redirection optical element may comprise a multichroic beam combiner, wherein the multichroic beam combiner is configured to one or more of: (A) transmit light received by the second redirection optical element and having one of (i) a wavelength below a first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cutoff wavelength (Xcoi), and reflect light received by the second redirection optical element and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cut-off wavelength (Xcoi); wherein + 5 nm < XcOi< +imc - 10 nm; (B) transmit light received by the second redirection optical element and having one of (i) a wavelength below a second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element and having the other of (i) a wavelength below the second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength (Xco2); wherein Ximc+ 10 nm < Xc<>2 < Xc3 - 5 nm; (C) transmit light received by the second redirection optical element and having one of (i) a wavelength below a first cut-off wavelength (Xcoi) and above a second cut-off wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and above the second cut-off wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2); wherein z + 5 nm < XcOi< +imc -10 nm and Ximc + 10 nm < Xc<>2 < A- - 5 nm; (D) transmit light received by the second redirection optical element and having one of (i) a wavelength below a second cut-off wavelength (Xco2) and above a third cut-off wavelength (Xcos), and (ii) a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xcos), and reflect light received by the second redirection optical element and having the other of (i) a wavelength below the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xcos), and (ii) a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xcos); wherein Ximc+ 10 nm < >^<>2 < A3 - 5 nm and A<>3 > A3 + 5 nm; and (E) transmit light received by the second redirection optical element and having one of (i) a wavelength below a first cut-off wavelength (λco1) and between a second cut-off wavelength (λco2) and a third cut-off wavelength (λco3), and (ii) a wavelength between the first cut-off wavelength (λco1) and the second cut-off wavelength (λco2) and above the third cut-off2025PF80043

[0186] 43

[0187] wavelength (Xcos), and reflect light received by the second redirection optical element and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and between the second cut-off wavelength ( 02) and the third cut-off wavelength (Xcos), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Koi) and above the third cut-off wavelength ( 03); wherein Kz + 5 nm < Xcoi < imc - 10 nm, imc + 10 nm < Xco2 < Xc3 - 5 nm and A<>3 > K3 + 5 nm. Such a second redirection optical element may facilitate combining the diffused blueish device light, the diffused diffuser device light, and the luminescent material light into on optical path to the light exit with relatively few losses in especially the luminescent material light and the diffused diffuser device light.

[0188] In embodiments, the second redirection optical element may receive the luminescent material light via the diffuser redirection optical element. Hence, in embodiments, the diffuser redirection optical element may be configured in an optical path between the luminescent material and the second redirection optical element. In such embodiments, the diffuser redirection optical element may be configured to direct the luminescent material light, received by the diffuser redirection optical element, into an optical path to the second redirection optical element. As indicated above, the diffuser redirection optical element may comprise a multichroic beam splitter. Especially, the cut-off wavelength (Xco) of the multichroic beam splitter (see also above) may be (configured) between the blueish centroid wavelength (λc2) and the luminescent material centroid wavelength (λlmc). That is, Kz < o < Kmc may apply, such as Kz + 2 nm < o < Kmc - 2 nm, especially Kz + 5 nm < Ko < Kmc - 5 nm, like Kz + 10 nm < Ko < Kmc - 10 nm. Further, the light generating system may be configured such, that the luminescent material light and the diffuser device light may be incident on the diffuser redirection optical element from parallel yet opposite (i.e., antiparallel) directions. Additionally, the light generating system may be configured such, that (i) the luminescent material light, and (ii) the (diffused) blueish device light and the diffused diffuser device light may be incident on the diffuser redirection optical element from orthogonal directions. For instance, the diffuser redirection optical element may in such embodiments especially be configured to (a) reflect the luminescent material light, received by the diffuser redirection optical element, into an optical path to the second redirection optical element, (b) reflect the diffuser device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly, (c) transmit the blueish device light, received by the diffuser redirection optical element, into an optical path to the diffuser assembly, and (d) transmit the diffused blueish device light and the diffused diffuser device light, received by the diffuser redirection optical element, into an optical path2025PF80043

[0189] 44

[0190] to the second redirection optical element. Hence, in specific embodiments, the diffuser redirection optical element may be configured in an optical path between the luminescent material and the second redirection optical element; wherein the diffuser redirection optical element may be configured to direct the luminescent material light, received by the diffuser redirection optical element, into an optical path to the second redirection optical element; wherein the light generating system may be configured such, that (i) the luminescent material light, and (ii) the diffused blueish device light and diffused diffuser device light may be incident on the diffuser redirection optical element from orthogonal directions. Such a configuration may reduce the number of optics needed to combine the luminescent material light and the diffused device light(s) (especially in embodiments wherein the luminescent material may be configured in the transmissive mode).

[0191] Yet, alternatively, the optics may further comprise a combiner redirection optical element. The combiner redirection optical element may be configured in an optical path between the luminescent material and the light exit. Further, the combiner redirection optical element may be configured in an optical path between the diffuser redirection optical element and the light exit. In embodiments, the combiner redirection optical element may (at least) comprise a multichroic beam splitter. Especially, the multichroic beam splitter may have one or more of the first cut-off wavelength (λco1), the second cut-off wavelength (λco2), and the third cut-off wavelength (λco3) as defined above for the second redirection optical element. Further, the combiner redirection optical element may comprise a polarizing beam splitter (PBS), wherein the combiner redirection optical element may especially have a polarizing beam splitting functionality for the (diffused) blueish device light (i.e., for light having the blueish centroid wavelength (λc2)). The combiner redirection optical element may especially be configured to direct the luminescent material light, the diffused blueish device light, and the diffused diffuser device light, received by the combiner redirection optical element, into an optical path to the light exit. Especially, the combiner redirection optical element may combine a beam of the luminescent material light with a beam of diffused (blueish and diffuser) device light, and direct the combined beam into an optical path to the light exit. Hence, the light generating system may be configured such, that the luminescent material light and the diffused device light may be incident on the combiner redirection optical element from orthogonal directions. Hence, in specific embodiments, the optics may comprise a combiner redirection optical element; wherein the combiner redirection optical element may be configured (i) in an optical path between the luminescent material and the light exit, and (ii) in an optical path between the diffuser redirection optical element and the2025PF80043

[0192] 45

[0193] light exit; wherein the combiner redirection optical element may comprise a multichroic beam splitter; wherein the combiner redirection optical element may be configured to direct the luminescent material light, the diffused blueish device light, and the diffused diffuser device light, received by the combiner redirection optical element, into an optical path to the light exit; wherein the light generating system may be configured such, that the luminescent material light and the diffused device light may be incident on the combiner redirection optical element from orthogonal directions. Such a combiner redirection optical element may facilitate simplifying the spectral requirements of the second redirection optical element. Further, such a combiner redirection optical element may facilitate combining a beam of luminescent material light with a beam of diffused device light upstream of the light exit.

[0194] In embodiments, the second redirection optical element may be configured in an optical path between the combiner redirection optical element and the light exit. Hence, in embodiments, luminescent material light and diffused device light, emanating away from the combiner redirection optical element, may be directed into an optical path to the light exit via the second redirection optical element. In such embodiments, the second redirection optical element may especially function as a polarizing beam splitter for the (diffused) blueish device light (i.e., for light having the blueish centroid wavelength (λc2)), wherein the second redirection optical element may optionally further comprise a multichroic beam splitter with a (single) cut-off wavelength (Xco) configured between (i) the blueish centroid wavelength (Xc2) and (ii) the luminescent material centroid wavelength ( imc) and the diffuser centroid wavelength (λc3). Yet, alternatively, the combiner redirection optical element may be configured in an optical path between the second redirection optical element and the light exit. In such embodiments, the combiner redirection optical element may be a multichroic beam splitter (and thus may not comprise a polarizing beam splitter). Hence, in specific embodiments, one of the following may apply: (a) the second redirection optical element may be configured in an optical path between the combiner redirection optical element and the light exit; and (b) the combiner redirection optical element may be configured in an optical path between the second redirection optical element and the light exit.

[0195] A geometric beam combiner (GBC) 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, 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 from2025PF80043

[0196] 46

[0197] the direction of the incident light. Conversely, light from another part of the light sources (configured to provide light at a different location on the GBC than the previous part) may be transmitted by the GBC. That is, 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. Therefore, at least part of the GBC may comprise a light transmissive, especially a light transparent, material. Such reflection or transmission of the light may, in embodiments, depend on the geometric-optical design of the GBC. Hence, a GBC may provide geometric (or spatial) beam combining functionality by combining two incident device light source beams into an output (or combined) beam with an etendue that may be smaller than the sum of the etendues of the two incident device light beams, where the etendue may refer to the surface area defined by the smallest outer circumference of a light beam and the corresponding angular distribution of the light beam, i.e., independent of their polarization and / or wavelength. Etendue may especially be defined in mm2sr.

[0198] In some embodiments, the GBC (or geometric beam redirector) may be configured to transmit or reflect light received by the GBC in dependence of its angle of incidence relative to a surface normal (Ni) of the GBC. Additionally or alternatively, the GBC may be configured to transmit or reflect light received by the GBC in dependence of its total internal reflection relative to the GBC. In particular, the GBC may be engineered such that light incident on different spatial locations on the geometric beam combiner may be differently redirected, e.g. transmitted or reflected. Especially, in embodiments, the GBC may be engineered such that the transmissive and reflective optical features of the geometric beam redirector may be tailored to the geometries of the light sources in the light generating devices (e.g. the lasers in a laser bank). As such, in embodiments, the GBC may be configured to combine device light received from two different optical paths (e.g. pump device light and blueish device light orthogonally provided to the GBC) into the same optical path (or direction). Such embodiments may be beneficial as optical power of different light generating devices may be combined without the need for expensive polarization based optical elements and / or differing wavelengths in the device light.

[0199] Hence, the second combiner redirection optical element may comprise a multichroic beam combiner (and / )or a geometric beam combiner. In embodiments where the second combiner redirection optical element comprises a geometric beam combiner, the pump centroid wavelength (Xci) and the blueish centroid wavelength (λc2) may be essentially the same wavelength, yet may also differ. Further, the light generating system may be configured such, that the pump device light and the blueish device light may be incident on2025PF80043

[0200] 47

[0201] the second combiner redirection optical element from orthogonal directions. That is, the second combiner redirection optical element may be configured to combine pump device light and blueish device light, received by the second combiner redirection optical element, into an optical path to the second redirection optical element. Further, the second redirection optical element may be configured to direct pump device light, received by the second redirection optical element, into an optical path to the luminescent material. Hence, in specific embodiments, the pump light generating device may be configured upstream of the second redirection optical element; wherein the optics may comprise a second combiner redirection optical element; wherein the second combiner redirection optical element may comprise a multichroic beam splitter or a geometric beam splitter; wherein the second combiner redirection optical element may be configured (i) in an optical path between the blueish light generating device and the second redirection optical element, and (ii) in an optical path between the pump light generating device and the second redirection optical element; wherein the light generating system may be configured such, that the pump device light and the blueish device light may be incident on the second combiner redirection optical element from orthogonal directions; and wherein the second combiner redirection optical element may be configured to direct the pump device light and the blueish device light, received by the second combiner redirection optical element, into an optical path to the second redirection optical element. Such a second combiner redirection optical element may facilitate combining (or mixing) the pump device light and blueish device light upstream of the second redirection optical element, thereby simplifying the spectral requirements of the other redirection optical elements and / or reducing (light) losses resulting from combining the pump device light and blueish device light with another of the redirection optical elements.

[0202] In embodiments, the light generating system may further comprise a fourth light generating device and a fifth redirection optical element. The fourth light generating device may especially be configured upstream of the fifth redirection optical element. That is, the fifth redirection optical element may be configured in a light receiving relationship with the fourth light generating device. The fourth light generating device may be configured to generate fourth device light. Further, in embodiments, the fourth light generating device may comprise a fourth light source, such as especially a fourth solid state light source. The fourth (solid state) light source may be essentially any light source, see also further below.

[0203] Especially, the pump solid state light source may be selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. The fourth light generating device may also comprise a plurality of fourth (solid state) light sources.2025PF80043

[0204] 48

[0205] Especially, in embodiments, the fourth light generating device may comprise a fourth laser bank (see also above). In such embodiments, the fourth laser bank may comprise a fourth array comprising a plurality of fourth solid state light sources, such as a plurality of fourth lasers. For example, the fourth array may comprise an n4*m4 array, as described above in relation to the blueish laser bank. In such embodiments, n4 and m4 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.

[0206] Further, the fourth light generating device may especially be configured to generate fourth device light having a fourth centroid wavelength (λc4). In embodiments, (at least part of) the fourth device light may have a fourth centroid wavelength (λc4) selected from the wavelength range of 400-530 nm, such as from the range of 420-520 nm, like from the range of 430-510 nm. Further, in embodiments, (at least part of) the fourth device light may have a fourth centroid wavelength (λc4) selected from the wavelength range of 440-530 nm, such as from the wavelength range of 450-510 nm. Hence, in embodiments, the fourth device light may be blue light or cyan light.

[0207] In embodiments, the fourth device light and the blueish device light may both comprise essentially the same type of blue light. Especially, in embodiments, |λc4-λc2| ≤ 10 nm, such as |λc4-λc2| ≤ 5 nm, like |λc4-λc2| ≤ 2 nm, including λc4= λc2. Alternatively, |λc4-λc2| ≥ 2 nm, such as |λc4-λc2| ≥ 5 nm, like |λc4-λc2| ≥ 10 nm. Such embodiments may provide improved color rendering and / or improved system efficiency. Yet, in embodiments, |λc4-λc2| ≤ 50 nm, such as |λc4-λc2| ≤ 40 nm, like |λc4-λc2| ≤ 25 nm, especially |λc4-λc2| ≤ 15 nm. Further, the fourth device light and the pump device light may both comprise essentially the same type of light. Especially, in embodiments, |λc4-λc1| ≤ 10 nm, such as |λc4-λc1| ≤ 5 nm, like |λc4-λc1| ≤ 2 nm, including λc4= λc1. Alternatively, |λc4-λc1| ≥ 2 nm, such as |λc4-λc1| ≥ 5 nm, like |λc4-λc1| ≥ 10 nm. Yet, in embodiments, |λc4-λc1| ≤ 50 nm, such as |λc4-λc1| ≤ 40 nm, like |λc4-λc1| ≤ 25 nm, especially |λc4-λc1| ≤ 15 nm.

[0208] In embodiments, in the first operational mode of the light generating system, the fourth light generating device may be operated at an adjustable drive current. Especially, the control system may be configured to control the adjustable drive current supplied to the fourth light generating device. Alternatively, the fourth light generating device may be operated at a constant drive current. In specific embodiments, in an operational mode, the fourth light generating device may be operated at its respective rated forward current, rated maximum forward current, or currents in between these former two. Yet, in embodiments, pulsed operation of the fourth light generating device may be applied. In such embodiments, the fourth light generating device may be operated at its rated peak forward current or its2025PF80043

[0209] 49

[0210] maximum peak forward current or currents in between these former two. Yet, as indicated above, the fourth light generating device may be operated at an adjustable drive current, such as at a current below its rated peak forward current or its maximum peak forward current.

[0211] In embodiments, the fifth redirection optical element may be configured(, with respect to the blueish device light,) in an optical path between the second redirection optical element and the luminescent material. In such embodiments, the fifth redirection optical element may be configured to direct the blueish device light, received by the fifth redirection optical element, into an optical path to the luminescent material. Further, in such embodiments, the fifth redirection optical element may be configured to direct the fourth device light, received by the fifth redirection optical element, into an optical path to the luminescent material. In embodiments, the light generating system may be configured such, that the blueish device light and the fourth device light may be incident on the fifth redirection optical element from orthogonal directions. Further, in embodiments, the fifth redirection optical element may comprise a polarizing beam splitter. In such embodiments, a polarization of the blueish device light received by the fifth redirection optical element may be complementary to a polarization of the fourth device light received by the fifth redirection optical element (wherein further one of λc2 = λc4 and λc2 ≠ λc4 may apply). Alternatively, in embodiments, the fifth redirection optical element may comprise a multichroic beam splitter, wherein |Xc4-Xc2| > 5 nm may apply (and wherein the fourth device light may have any possible polarization). Yet, in embodiments, the fifth redirection optical element may comprise a geometric beam combiner (GBC), wherein the GBC may combine the blueish device light and the fourth device light irrespective or their respective polarizations and centroid wavelengths. As indicated above, the fifth redirection optical element may be configured to direct (at least part of) the fourth device light, received by the fifth redirection optical element, into an optical path to the luminescent material. Especially, the luminescent material may be configured to convert at least part of the fourth device light, received by the luminescent material, into luminescent material light.

[0212] Yet, in alternative embodiments, the fifth redirection optical element may be configured in an optical path between the pump light generating device and the second combiner redirection optical element. In such embodiments, the fifth redirection optical element may be configured to direct the pump device light, received by the fifth redirection optical element, into an optical path to the second combiner redirection optical element. Further, in such embodiments, the fifth redirection optical element may be configured to direct the fourth device light, received by the fifth redirection optical element, into an optical2025PF80043

[0213] 50

[0214] path to the second combiner redirection optical element. Especially, the light generating system may be configured such, that the pump device light and the fourth device light may be incident on the fifth redirection optical element from orthogonal directions. In embodiments, the fifth redirection optical element may comprise a polarizing beam splitter. In such embodiments, a polarization of the pump device light received by the fifth redirection optical element may be complementary to a polarization of the fourth device light received by the fifth redirection optical element (wherein further one of λc1 = λc4 and λc1 ≠ λc4 may apply). Alternatively, in embodiments, the fifth redirection optical element may comprise a multi chroic beam splitter, wherein |Xc4-Xci | > 5 nm may apply (and wherein the fourth device light may have any possible polarization). Yet, in embodiments, the fifth redirection optical element may comprise a GBC, wherein the GBC may combine the pump device light and the fourth device light irrespective or their respective polarizations and centroid wavelengths.

[0215] Hence, the fifth redirection optical element may be configured to direct the pump device light and the fourth device light, received by the fifth redirection optical element, into an optical path to the second combiner redirection optical element. In embodiments, the second redirection optical element may be configured to direct the fourth device light, received by the second redirection optical element, to one or more of (a) the luminescent material, and (b) the diffuser assembly. Would at least part of the fourth device light be incident on the luminescent material, the luminescent material may be configured to convert at least part of (said at least part of) the fourth device light, received by the luminescent material, into luminescent material light. Additionally or alternatively, would at least part of the fourth device light be incident on the diffuser assembly, the diffuser may be configured to diffuse the fourth device light, received by the diffuser assembly, into diffused fourth device light. In such embodiments, and in an operational mode of the light generating system, the system light may comprise the diffused fourth device light. Hence, in specific embodiments, the light generating system may further comprise a fourth light generating device and a fifth redirection optical element; wherein the fourth light generating device may be configured upstream of the fifth redirection optical element; wherein the fourth light generating device may be configured to provide fourth device light having a fourth centroid wavelength (λc4) selected from the wavelength range of 430-510 nm; wherein the fourth light generating device may comprise a fourth solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; wherein one of the following may apply: (A) the fifth redirection optical element may be configured in an optical path between the second redirection optical element and the2025PF80043

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[0217] luminescent material; wherein the fifth redirection optical element may be configured to direct the blueish device light and the fourth device light, received by the fifth redirection optical element, into an optical path to the luminescent material; wherein the luminescent material may be configured to convert at least part of the fourth device light, received by the luminescent material, into luminescent material light; and (B) the fifth redirection optical element may be configured in an optical path between the pump light generating device and the second combiner redirection optical element; wherein the fifth redirection optical element may be configured to direct the pump device light and the fourth device light, received by the fifth redirection optical element, into an optical path to the second combiner redirection optical element; wherein the second redirection optical element may be configured to direct the fourth device light, received by the second redirection optical element, into an optical path to one or more of (a) the luminescent material, wherein the luminescent material may be configured to convert at least part of the fourth device light, received by the luminescent material, into luminescent material light; and (b) the diffuser assembly, wherein the diffuser may be configured to diffuse the fourth device light, received by the diffuser assembly, into diffused fourth device light, and wherein, in an operational mode of the light generating system, the system light may comprise the diffused fourth device light. Such a fourth light generating device may facilitate providing system light with a relatively larger contribution of luminescent material light. Alternatively, such a fourth light generating device may facilitate providing system light comprising diffused cyan device light, wherein the diffused cyan device light may “fill” a spectral gap in the spectral power distribution of the system light between the blueish device light and the luminescent material light. Hence, with such a fourth light generating device, a higher CRI may be provided, and / or the spectral power distribution of the system light may better mimic a spectral power distribution of natural (sun)light.

[0218] Hence, the second redirection optical element may be configured to direct the fourth device light, received by the second redirection optical element, to one or more of the luminescent material and the diffuser assembly. In embodiments, λc4 ≠ λc2 may apply, wherein the second redirection optical element may comprise a PBS (only) for the blueish device light (i.e., device light having the second centroid wavelength (λc2)), and wherein the second redirection optical element may (thus) not comprise a PBS for the fourth device light (i.e., device light having the fourth centroid wavelength (λc4)), such that the second redirection optical element may be configured to (fixedly) direct the fourth device light to one of the luminescent material and the diffuser assembly (regardless of the polarization of2025PF80043

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[0220] the fourth device light). Alternatively, one of λc4 = λc2 and λc4 ≠ λc2 may apply, wherein the second redirection optical element may (further) comprise a PBS for the fourth device light (i.e., device light having the fourth centroid wavelength (λc4)), and wherein the second redirection optical may be configured to direct the fourth device light to one or more of the luminescent material and the diffuser assembly in dependence of the polarization of the fourth device light. In embodiments, the fourth device light, received by the second redirection optical element, may have a fixed polarization. In such embodiments, a first part of the fourth device light may be directed to the luminescent material, and a second part of the fourth device light may be directed to the diffuser assembly, depending on the fixed polarization of the fourth device light (wherein optionally one of the first part and the second part may represent essentially 0% of the spectral power of the fourth device light received by the second redirection optical element). Yet, in embodiments, the control system, such as especially the polarization control system, may be configured to control a (linear) polarization of the fourth device light received by the second redirection optical element. That is, the polarization control system may be configured to control an adjustable intensity (or power) contribution of the fourth device light directed to the luminescent material and / or to the diffuser assembly. Especially, the polarization control system may comprise one or more of (i) a movement element configured to rotate the fourth light generating device, and (ii) a second (optical) retarder element configured in an optical path between the fourth light generating device and the second redirection optical element, such as especially between the fourth light generating device and the fifth redirection optical element (wherein the second retarder element may be identical to the first retarder element described above). Hence, in specific embodiments, the second redirection optical element may be configured to direct the fourth device light to one or more of the luminescent material and the diffuser assembly in dependence of its linear polarization. Such configurations may allow for further adjusting the optical characteristics of the system light, as the device light from at least two light generating devices may be (adjustably) directed towards the luminescent material and the diffuser assembly.

[0221] As indicated above, in embodiments, the light generating system may comprise a control system. The control system may be configured to control one or more of the spectral power distribution, the CCT, the CRI, the color gamut, and the radiant flux of the system light. The control system may especially be configured to control the optical characteristics of the system light by one or more of controlling the polarization control system and controlling the (adjustable) drive current supplied to one or more of the light2025PF80043

[0222] 53

[0223] generating devices. In embodiments, the control system may be configured to control the optical characteristics of the system light in dependence of one or more of an input signal from a user interface, a sensor signal, and a timer. 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 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 be at least temporarily, or permanently, functionally 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.

[0224] The control system may be configured to receive and execute instructions from a remote control. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system. 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.. 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, wherein 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.

[0225] The system, or apparatus, or device may execute an action in a “mode” 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” or2025PF80043

[0226] 54

[0227] “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. However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode.

[0228] In further embodiments, the optics may comprise (at least) condensing optics. The condensing optics may especially comprise a first condensing optics configured (directly) upstream of the luminescent material and a second condensing optics configured (directly) upstream of the diffuser. Especially, in embodiments, the first condensing optics and the second condensing optics may each comprise at least one positive lens. In specific embodiments (such as e.g. when the luminescent material is configured in a reflective mode) the first condensing optics may comprise a first positive lens and a second smaller positive lens. In such embodiments, the smaller positive lens may especially be located between (relative to the propagation of light through the system) the first positive lens and the luminescent material or diffuser, respectively.

[0229] In further embodiments, the optics may comprise (at least) collimator optics (or “collimating optics”), especially collecting and collimating optics. Especially, the optics may comprise a first collecting and collimating optics configured (directly) downstream of the luminescent material and a second collecting and collimating optics configured (directly) downstream of the diffuser.

[0230] Hence, in embodiments, the light generating system may further comprise one or more of (a) condensing and / or collimating optics, and (b) integrating optics. Especially, condensing and / or collimating optics may be configured at one or more positions selected from: (i) in an optical path between the second redirection optical element and the luminescent material, (ii) in an optical path between the diffuser redirection optical element and the diffuser, and (iii) in an optical path between the second redirection optical element and the light exit. Additionally or alternatively, integrating optics may be configured at one or more positions selected from: (i) in an optical path between the pump light generating device and the combiner redirection optical element, (ii) in an optical path between the second combiner redirection optical element and the second redirection optical element, (iii) in an optical path between the third light generating device and the diffuser assembly, (iv) in an optical path between the blueish light generating device and the second redirection optical element, (v) in an optical path between the combiner redirection optical element and the2025PF80043

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[0232] second redirection optical element, and (vi) and in an optical path between the second redirection optical element and the light exit.

[0233] 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.

[0234] The terms “violet light” or “violet emission” especially relates to light having a wavelength in the range of about 380-440 nm. The terms “green light” or “green emission” especially relate to light having a wavelength in the range of about 495-570 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 570-590 nm. The terms “orange light” or “orange emission” especially relate to light having a wavelength in the range of about 590-620 nm. The term “cyan” may refer to one or more wavelengths selected from the range of about 490-520 nm.

[0235] 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 lighting fixture, a projector device, and an automotive lighting device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the (first, second, and third) light generating devices, the luminescent material, the optics, and the diffuser assembly.

[0236] The term “centroid wavelength”, also indicated as λc, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that2025PF80043

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[0238] divides the integral of a spectral power distribution into two equal parts as expressed by the formula λc = Σ λ*I(λ) / (Σ I( λ)), where the summation is over the wavelength range of interest, and I(X) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions.

[0239] BRIEF DESCRIPTION OF THE DRAWINGS

[0240] 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:

[0241] Figs. 1-9 schematically depict some embodiments of the light generating system; and

[0242] Fig. 10 schematically depicts some applications of the light generating system in lighting devices. The schematic drawings are not necessarily to scale.

[0243] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0244] Fig. 1 schematically depicts an embodiment of the light generating system 1000 comprising a blueish light generating device 120, a diffuser light generating device 130, optics 500, a diffuser assembly 700, and a light exit 1090. The blueish light generating device 120 may be configured to provide blueish device light 121 having a blueish centroid wavelength selected from the wavelength range of 430-490 nm. Further, the blueish light generating device 120 may comprise a blueish solid state light source 20. Conversely, the diffuser light generating device 130 may be configured to provide diffuser device light 131 having a diffuser centroid wavelength λc3 selected from the wavelength range of 470-780 nm. The diffuser light generating device 130 may especially comprise a diffuser solid state light source 30. In embodiments, |Xc3-Xc2| > 10 nm may apply. Further, the blueish and diffuser solid state light sources 20,30 may be individually selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. The optics 500 may comprise a diffuser redirection optical element 530. Especially, the diffuser redirection optical element 530 may be configured (i) in an optical path between the blueish light generating device 120 and the diffuser assembly 700, and (ii) in an optical path between the diffuser light generating device 130 and the diffuser assembly 700. Further, the diffuser redirection optical element 530 may be configured (i) to direct blueish device light 121, received by the diffuser redirection optical element 530, into an optical path to the diffuser2025PF80043

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[0246] assembly 700, and (ii) to direct diffuser device light 131, received by the diffuser redirection optical element 530, into an optical path to the diffuser assembly 700.

[0247] The diffuser assembly 700 may comprise a diffuser 710 configured to diffuse at least part of the blueish device light 121, received by the diffuser assembly 700 via the diffuser redirection optical element 530, into diffused blueish device light 721, and at least part of the diffuser device light 131, received by the diffuser assembly 700 via the diffuser redirection optical element 530, into diffused diffuser device light 731. The diffuser assembly 700 may be configured to direct the diffused blueish device light 721 and the diffused diffuser device light 731, emanating away from the diffuser 710, into an optical path to the diffuser redirection optical element 530. Hence, the diffuser redirection optical element 530 may further be configured to: (i) direct the diffused blueish device light 721, received by the diffuser redirection optical element 530, into an optical path to the light exit 1090, and (ii) direct the diffused diffuser device light 731, received by the diffuser redirection optical element 530, into an optical path to the light exit 1090. In such embodiments, (i) an optical axis of the blueish device light 121 upstream of the diffuser redirection optical element 530, and (ii) an optical axis of the diffused blueish device light 721 and the diffused diffuser device light 731 downstream of the diffuser redirection optical element 530, may be co-axial. Further, the light generating system 1000 may be configured such, that the blueish device light 121 and the diffuser device light 131 may be incident on the diffuser redirection optical element 530 from orthogonal directions.

[0248] The light generating system 1000 may be configured to generate system light 1001. Especially, in a first operational mode of the light generating system 1000, the system light 1001 may comprise at least part of the diffused blueish device light 721 and at least part of the diffused diffuser device light 731.

[0249] In Fig. 1, an embodiment of the light generating system 1000 comprising further (optical) components besides the blueish light generating device 120, diffuser light generating device 130, optics 500, diffuser assembly 700, and light exit 1090 is schematically depicted. Note however, that the light generating system 1000 as defined herein is not limited to such embodiments, and that especially the diffuser assembly 700 and diffuser redirection optical element 530 may be applied in many alternative embodiments and lighting systems, not necessarily depicted or described herein.

[0250] As schematically depicted in Fig. 1, the diffuser 710 may be configured in the transmissive mode. In such configurations of the diffuser 710, the diffuser assembly 700 may further comprise an assembly polarization converter 750 configured in an optical path2025PF80043

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[0252] between the diffuser redirection optical element 530 and the diffuser 710. The assembly polarization converter 750 may be configured to convert (diffused) device light comprising one of a first linear polarization and a second linear polarization into (diffused) device light comprising the other one of the first linear polarization and the second linear polarization. Hence, the assembly polarization converter 750 may especially comprise a half waveplate or X / 2 plate. Further, the light generating system 1000 may comprise a plurality of reflectors 560 configured to (i) reflect device light received from the diffuser redirection optical element 530 in an optical path to the diffuser assembly 700 and / or (ii) reflect diffused device light emitted by the diffuser 710 in an optical path to the diffuser redirection optical element 530. Especially, the reflectors 560 may guide the (diffused) device light in a loop through the diffuser assembly 700.

[0253] Further, as depicted in Fig. 1, and in the transmissive mode of the diffuser 710, an optical axis Oi2 of the blueish device light 121 reaching the diffuser 710 and an optical axis Oi3 of the diffuser device light 131 reaching the diffuser 710 may be parallel.

[0254] Additionally, an optical axis Ot2 of the diffused blueish device light 721 emanating away from the diffuser 710 and an optical axis Ot3 of the diffused diffuser device light 731 emanating away from the diffuser 710 may be parallel. Alternatively, as e.g. schematically depicted in Fig. 4, the diffuser 710 may be configured in the transmissive mode, wherein an optical axis Oi2 of the blueish device light 121 reaching the diffuser 710 and an optical axis Oi3 of the diffuser device light 131 reaching the diffuser 710 may be antiparallel (i.e., parallel, yet propagating in opposite directions). Further, in such embodiments, an optical axis Ot2 of the diffused blueish device light 721 emanating away from the diffuser 710 and an optical axis Ot3 of the diffused diffuser device light 731 emanating away from the diffuser 710 may be antiparallel.

[0255] The diffuser redirection optical element 530 may comprise a polarizing beam splitter configured to, in dependence of their respective polarizations: (i) reflect three types of light and transmit one type of light, or (ii) transmit three types of light and reflect one type of light. In both cases, the types of light may be selected from the group consisting of: (i) blueish device light 121 received by the diffuser redirection optical element 530 from the blueish light generating device 120, (ii) diffused blueish device light 721 received by the diffuser redirection optical element 530 from the diffuser assembly 700, (iii) diffuser device light 131 received by the diffuser redirection optical element 530 from the diffuser light generating device 130, and (iv) diffused diffuser device light 731 received by the diffuser redirection optical element 530 from the diffuser assembly 700. In the embodiment depicted2025PF80043

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[0257] in Fig. 1, the diffuser redirection optical element 530 may especially be configured to reflect blueish device light 121, and transmit diffuser device light 131, diffused blueish device light 721, and diffused diffuser device light 731.

[0258] In embodiments, the diffuser redirection optical element 530 may (further) comprise a multichroic beam splitter. The multichroic beam splitter may comprise a cut-off wavelength (Xc0), wherein one applies of (i) Ki < Ko < 3, and (ii) K3 < o < K2. Hence, the multichroic beam splitter may reflect one of the (diffused) blueish device light 121,721 and (diffused) diffuser device light 131,731 and transmit the other of the (diffused) blueish device light 121,721 and (diffused) diffuser device light 131,731 based on a difference in centroid wavelength.

[0259] As indicated above, the diffuser redirection optical element 530 may direct one of the (diffused) blueish device light 121,721 and the (diffused) diffuser device light 131,731 independent from the polarization of said (diffused) device light, while directing the other of the (diffused) blueish device light 121,721 and the (diffused) diffuser device light 131,731 in dependence of the polarization of said (diffused) device light. Hence, the diffuser 710 may (need to) be a polarization maintaining diffuser for at least one of the blueish device light 121 and the diffuser device light 131. Further, the light generating system 1000 may be configured such, that the at least one of the blueish device light 121 and the diffuser device light 131 received by the diffuser redirection optical element 530 may comprise one of the first linear polarization and the second linear polarization.

[0260] As indicated above, the light generating system 1000 may comprise further (optical) components. Especially, the light generating system 1000 may further comprise a luminescent material 200. Further, the optics 500 may further comprise a second redirection optical element 520. The second redirection optical element 520 may be configured in an optical path between the blueish light generating device 120 and the diffuser redirection optical element 530. Further, the second redirection optical element 520 may comprise a polarizing beam splitter. Especially, the second redirection optical element 520 may be configured to direct the blueish device light 121, received by the second redirection optical element 520, into an optical path to the luminescent material 200 and / or the diffuser assembly 700 in dependence of its linear polarization. For example, in Fig. 1, the second redirection optical element 520 may direct s-polarized blueish device light 121 to the diffuser assembly 700, and direct p-polarized blueish device light 121 to the luminescent material 200. The luminescent material 200 may be configured to convert at least part of the blueish device light 121, received by the luminescent material 200 via the second redirection optical2025PF80043

[0261] 60

[0262] element 520, into luminescent material light 201. Especially, the luminescent material light 201 may have a luminescent material centroid wavelength (λlmc). In embodiments, |λc3-λlmc| ≥ 10 nm. Further, in a first operational mode of the light generating system 1000, the system light 1001 may be white light comprising at least part of the luminescent material light 201, at least part of the diffused blueish device light 721, and at least part of the diffused diffuser device light 731.

[0263] The luminescent material 200 may be configured on a support 1250, such as especially a thermally conductive support. The support 1250 may comprise, such as be, a rotating element 1260. Hence, the luminescent material 200 may be configured on the rotating element 1260. Especially, the luminescent material 200 may be in a reflective mode.

[0264] The light generating system 1000 may be configured such, that the blueish device light 121 reaching the second redirection optical element 520 may comprise a controllable polarization. Hence, the light generating system 1000 may comprise a control system 300 and a polarization control system 600. The polarization control system 600 may be configured to control the polarization of the blueish device light 121 reaching the second redirection optical element 520. Further, the control system 300 may be configured to control one or more of a spectral power distribution, a correlated color temperature, a color gamut, and a color rendering index of the system light 1001 by controlling the polarization control system 600. The polarization control system 600 may comprise a first retarder element 610 configured in an optical path between the blueish light generating device 120 and the second redirection optical element 520 (see e.g. Fig. 3). In such embodiments, the control system 300 may be configured to control rotation of the first retarder element 610. The first retarder element 610 may especially comprise a X / 2 waveplate. Additionally or alternatively, the polarization control system 600 may comprise a movement element 630 configured to rotate the blueish light generating device 120. In such embodiments, the control system 300 may be configured to control the movement element 630.

[0265] Turning to the second redirection optical element 520, the second redirection optical element 520 may further be configured in an optical path between the diffuser redirection optical element 530 and the light exit 1090. Hence, the second redirection optical element 520 may be configured to direct the luminescent material light 201, the diffused blueish device light 721, and the diffused diffuser device light 731, received by the second redirection optical element 520, into an optical path to the light exit 1090. In such embodiments, the luminescent material centroid wavelength (λlmc) may especially be selected from the range of 500-600 nm. Further, in such embodiments, the second redirection optical2025PF80043

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[0267] element 520 may comprise a multichroic beam combiner. The multichroic beam combiner may have one or more of the following embodiments. In a first embodiment, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element 520 and having one of (i) a wavelength below a first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cut-off wavelength (Xcoi), and reflect light received by the second redirection optical element 520 and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cut-off wavelength (Xcoi). In such embodiments, +c2 + 5 nm < Xcoi < +imc - 10 nm. In a second embodiment, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element 520 and having one of (i) a wavelength below a second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element 520 and having the other of (i) a wavelength below the second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength (Xco2). In such embodiments, Ximc + 10 nm < Xc<>2 < 3 - 5 nm. In a third embodiment, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element 520 and having one of (i) a wavelength below a first cut-off wavelength (Xcoi) and above a second cut-off wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and above the second cut-off wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (^02). In such embodiments, +c2 + 5 nm < Xcoi < +imc - 10 nm and +imc+ 10 nm < >^<>2 < +c3 - 5 nm. In a fourth embodiment, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element 520 and having one of (i) a wavelength below a second cut-off wavelength (Xco2) and above a third cut-off wavelength (Xc03), and (ii) a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xc03), and reflect light received by the second redirection optical element 520 and having the other of (i) a wavelength below the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xc03), and (ii) a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xco3). In such embodiments, Ximc + 10 nm < >^<>2 < 3 - 5 nm and +c<>3 > 3 + 5 nm. Finally, in a fifth embodiment, the multichroic beam combiner may be configured to transmit light received by the second redirection optical element 520 and having one of (i) a wavelength below a first cut-off wavelength (Xcoi) and between a second cut-off wavelength (Xco2) and a2025PF80043

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[0269] third cut-off wavelength (Xcos), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (A02) and above the third cut-off wavelength (Xcos), and reflect light received by the second redirection optical element 520 and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and between the second cut-off wavelength (Xco2) and the third cut-off wavelength (Xcos), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (A02) and above the third cut-off wavelength (Xcos). In such embodiments, A2 + 5 nm < Aoi < imc - 10 nm, X|mc+ 10 nm < Xco2 < Xc3 - 5 nm and A<>3 > A-3 + 5 nm.

[0270] The light generating system 1000 may further comprise one or more of (i) condensing and / or collimating optics 580, and (ii) integrating optics 570.

[0271] Fig. 2 schematically depicts a further embodiment of the light generating system 1000. As depicted in Fig. 2, the diffuser 710 may be configured in the reflective mode. In such configurations, the diffuser assembly 700 may be configured such, that an optical axis of the blueish and diffuser device light 121,131 reaching the diffuser 710 and an optical axis of the diffused blueish and diffuser device light 721,731 reflecting from the diffuser 710 may be co-axial. Further, in such configurations, the diffuser assembly 700 may comprise a polarization converter 720 configured in an optical path between the diffuser redirection optical element 530 and the diffuser 710. The polarization converter 720 may especially be configured to convert (i) device light comprising one of the first linear polarization and a second linear polarization, different from the first linear polarization, into device light comprising an elliptical polarization, and (ii) diffused device light comprising an elliptical polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization. Hence, the polarization converter 720 may especially comprise a X / 4 plate.

[0272] As depicted, the diffuser 710 (in the reflective mode) may be configured on the rotating element 1260. Hence, the light generating system 1000 may comprise a rotating element 1260, wherein one or more of (a) the luminescent material 200 and (b) the diffuser 710 may be configured on the rotating element 1260. Especially, said one or more of (a) the luminescent material 200 and (b) the diffuser 710 may be configured in the reflective mode.

[0273] Fig. 3 schematically depicts a further embodiment of the light generating system 1000. Also here, the diffuser 710 may be configured in the reflective mode. However, in the embodiment depicted in Fig. 3, the diffuser assembly 700 may be configured such that an optical axis of the blueish and diffuser device light 121,131 reaching the diffuser 710 and an optical axis of the diffused blueish and diffuser device light 721,731 reflecting from the2025PF80043

[0274] 63

[0275] diffuser 710 may not be co-axial. Further, in such embodiments, the diffuser assembly 700 may comprise an assembly polarization converter 750 configured in an optical path between the diffuser redirection optical element 530 and the diffuser 710. The assembly polarization converter 750 may be configured to convert (diffused) device light comprising one of the first linear polarization and the second linear polarization into (diffused) device light comprising the other one of the first linear polarization and the second linear polarization. Further, the light generating system 1000 may comprise a plurality of reflectors 560 configured to (i) reflect device light received from the diffuser redirection optical element 530 in an optical path to the diffuser assembly 700 and / or (ii) reflect diffused device light received from the diffuser 710 in an optical path to the diffuser redirection optical element 530. Optionally, the diffuser assembly 700 may comprise a condenser optical element 734 configured in an optical path between (a) one of the assembly polarization converter 750 and the diffuser redirection optical element 530 and (b) the diffuser 710. Further, the diffuser assembly 700 may comprise a collecting optical element 735 configured in an optical path between (a) the diffuser 710 and (b) the other one of the assembly polarization converter 750 and the diffuser redirection optical element 530.

[0276] Note that also in embodiments wherein the diffuser 710 is configured in the reflective mode, such that the optical axis of the device light reaching the diffuser 710 and the optical axis of the diffused device light reflecting from the diffuser 710 are not co-axial, an optical axis Oi2 of the blueish device light 121 reaching the diffuser 710 and an optical axis Oi3 of the diffuser device light 131 reaching the diffuser 710 may be parallel, wherein similarly an optical axis Ot2 of the diffused blueish device light 721 emanating away from the diffuser 710 and an optical axis Ot3 of the diffused diffuser device light 731 emanating away from the diffuser 710 may be parallel (as schematically depicted in Fig. 3). Yet, alternatively, an optical axis Oi2 of the blueish device light 121 reaching the diffuser 710 and an optical axis Ot3 of the diffused diffuser device light 731 emanating away from the diffuser 710 may be antiparallel. Further, in such embodiments, an optical axis Ot2 of the diffused blueish device light 721 emanating away from the diffuser 710 and an optical axis Oi3 of the diffuser device light 131 reaching the diffuser 710 may be antiparallel.

[0277] In the embodiment of Fig. 3, the luminescent material 200 is configured in the transmissive mode. In such embodiments, the support 1250 may especially be transparent for (visible) light, such as transparent for at least blueish device light 121 (and luminescent material light 201). Further, in such embodiments, the light generating system 1000 may comprise a dichroic beam splitter (or “dichroic beam filter”) 210 configured (with respect to2025PF80043

[0278] 64

[0279] the blueish device light 121) (directly) upstream of the luminescent material 200. The dichroic beam splitter 210 may be configured to (i) transmit the blueish device light 121 received by the dichroic beam splitter 210, and (ii) reflect the luminescent material light 201 received by the dichroic beam splitter 210.

[0280] Further, the optics 500 may comprise a combiner redirection optical element 510. The combiner redirection optical element 510 may be configured in an optical path between the luminescent material 200 and the light exit 1090. Further, the combiner redirection optical element 510 may be configured in an optical path between the diffuser redirection optical element 530 and the light exit 1090. The combiner redirection optical element 510 may (at least) comprise a multi chroic beam splitter. Further, the combiner redirection optical element 510 may be configured to direct the luminescent material light 201, the diffused blueish device light 721, and the diffused diffuser device light 731, received by the combiner redirection optical element 510, into an optical path to the light exit 1090. Especially, the light generating system 1000 may be configured such, that the luminescent material light 201 and the diffused (blueish and diffuser) device light 721,731 may be incident on the combiner redirection optical element 510 from orthogonal directions. As depicted in Fig. 3, the combiner redirection optical element 510 may further be configured in an optical path between the second redirection optical element 520 and the light exit 1090, though this need not be the case (see e.g. Fig. 4 and Fig. 7).

[0281] Further, the light generating system 1000 may comprise a beam dump 800. The beam dump 800 may be configured to absorb light received by the beam dump 800 (e.g. luminescent material light 201 transmitted by the combiner redirection optical element 510 or diffused (blueish and / or diffuser) device light 721,731 reflected by the combiner redirection optical element 510).

[0282] Fig. 4 schematically depicts a further embodiment of the light generating system 1000. Here, the second redirection optical element 520 may not be configured to direct the diffused blueish and diffuser device light 721,731 to the light exit 1090. That is, the diffused blueish and diffuser device light 721,731 may not be incident on the second redirection optical element 520. Further, the luminescent material light 201 may not be incident on the second redirection optical element 520. Hence, in the embodiment depicted in Fig. 4, the second redirection optical element 520 may (simply) be a polarizing beam splitter for blueish device light 121, with no further spectral or optical requirements.

[0283] Fig. 5 schematically depicts an embodiment of the light generating system 1000 further comprising a pump light generating device 110. The pump light generating2025PF80043

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[0285] device 110 may be configured to provide pump device light 111 having a pump centroid wavelength (Xci) selected from the wavelength range of 430-490 nm. Further, the pump light generating device 110 may comprise a pump solid state light source 10 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction lightemitting diodes. The pump light generating device 110 may be configured upstream of one of (i) the combiner redirection optical element 510 (see e.g. Fig. 8), and (ii) the second redirection optical element 520. Further, said one of (i) the combiner redirection optical element 510 and (ii) the second redirection optical element 520 may be configured to direct the pump device light 111, received by the redirection optical element, into an optical path to the luminescent material 200. The luminescent material 200 may especially be configured to convert at least part of the pump device light 111, received by the luminescent material 200, into luminescent material light 201.

[0286] Hence, the pump light generating device 110 may be configured upstream of the second redirection optical element 520. In such embodiments, the optics 500 may further comprise a second combiner redirection optical element 540. The second combiner redirection optical element 540 may comprise a multichroic beam splitter or a geometric beam splitter (see e.g. Fig. 6). Further, the second combiner redirection optical element 540 may be configured (i) in an optical path between the blueish light generating device 120 and the second redirection optical element 520, and (ii) in an optical path between the pump light generating device 110 and the second redirection optical element 520. Especially, the light generating system 1000 may be configured such, that the pump device light 111 and the blueish device light 121 may be incident on the second combiner redirection optical element 540 from orthogonal directions. Further, the second combiner redirection optical element 540 may be configured to direct the pump device light 111 and the blueish device light 121, received by the second combiner redirection optical element 540, into an optical path to the second redirection optical element 520. Note that in Fig. 5, the second combiner redirection optical element 540 may comprise a multichroic beam splitter, such that |Xci -

[0287]

[0288] > 5 nm may apply.

[0289] Fig. 6 schematically depicts a further embodiment of the light generating system 1000, wherein the second combiner redirection optical element 540 may comprise a geometric beam splitter. In such embodiments, one of Xci = i and Xci i may apply. In the configuration of Fig. 6, the light generating system 1000 further comprises the combiner redirection optical element 510 and the beam dump 800.2025PF80043

[0290] 66

[0291] Fig. 7 schematically depicts a further embodiment of the light generating system 1000. Here, the second redirection optical element 520 may be configured in an optical path between the combiner redirection optical element 510 and the light exit 1090. Hence, in this embodiment, the luminescent material light 201, the diffused blueish device light 721, and the diffused diffuser device light 731 may be incident on the second redirection optical element 520 from the same (i.e., parallel) directions. Such embodiments may therefore simplify or reduce the spectral requirements of the second redirection optical element 520.

[0292] Fig. 8 schematically depicts a further embodiment of the light generating system 1000, wherein the pump light generating device 110 is configured upstream of the combiner redirection optical element 510. Further, as depicted in Fig. 8, the light generating system 1000 may comprise a fourth light generating device 140 and a fifth redirection optical element 550. The fourth light generating device 140 may be configured upstream of the fifth redirection optical element 550. Further, the fourth light generating device 140 may be configured to provide fourth device light 141 having a fourth centroid wavelength ( 4) selected from the wavelength range of 430-510 nm. The fourth light generating device 140 may comprise a fourth solid state light source 40 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0293] In the embodiment depicted in Fig. 8, the fifth redirection optical element 550 may be configured in an optical path between the second redirection optical element 520 and the luminescent material 200. In such embodiments, the fifth redirection optical element 550 may be configured to direct the blueish device light 121 and the fourth device light 141, received by the fifth redirection optical element 550, into an optical path to the luminescent material 200. Further, the luminescent material 200 may be configured to convert at least part of the fourth device light 141, received by the luminescent material 200, into luminescent material light 201. In embodiments, the light generating system 1000 may be configured such, that the blueish device light 121 and the fourth device light 141 may be incident on the fifth redirection optical element 550 from orthogonal directions.

[0294] Fig. 9 schematically depicts a further embodiment of the light generating system 1000, wherein the fifth redirection optical element 550 may further be configured in an optical path between the pump light generating device 110 and the second combiner redirection optical element 540. In such embodiments, the fifth redirection optical element 550 may be configured to direct the pump device light 111 and the fourth device light 141, received by the fifth redirection optical element 550, into an optical path to the second2025PF80043

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[0296] combiner redirection optical element 540. The second combiner redirection optical element 540 may be configured to direct the fourth device light 141, received by the second combiner redirection optical element 540, into an optical path to the second redirection optical element 520. Further, the second redirection optical element 520 may be configured to direct the fourth device light 141, received by the second redirection optical element 520, to one or more of (a) the luminescent material 200, wherein the luminescent material 200 may be configured to convert at least part of the fourth device light 141, received by the luminescent material 200, into luminescent material light 201; and (b) the diffuser assembly 700, wherein the diffuser 710 may be configured to diffuse the fourth device light 141, received by the diffuser assembly 700, into diffused fourth device light 741. Would at least part of the fourth device light 141 be directed to the diffuser assembly 700, such as in an operational mode of the light generating system 1000, (then) the system light 1001 may comprise the diffused fourth device light 741. The light generating system 1000 may be configured such, that the pump device light 111 and the fourth device light 141 may be incident on the fifth redirection optical element 550 from orthogonal directions. Further, in embodiments, the second redirection optical element 520 may be configured to direct the fourth device light 141 to one or more of the luminescent material 200 and the diffuser assembly 700 in dependence of its linear polarization.

[0297] Further, as depicted in Fig. 9, the diffuser redirection optical element 530 may be configured in an optical path between the luminescent material 200 and second redirection optical element 520. Hence, the diffuser redirection optical element 530 may be configured to direct the luminescent material light 201, received by the diffuser redirection optical element 530, into an optical path to the second redirection optical element 520. Further, the light generating system 1000 may be configured such, that (i) the luminescent material light 201, and (ii) the diffused blueish device light 721 and diffused diffuser device light 731 may be incident on the diffuser redirection optical element 530 from orthogonal directions.

[0298] Fig. 10 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. 10 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. 10 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a2025PF80043

[0299] 68

[0300] luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device.

[0301] Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor, reference 1310 to a ceiling, and reference 1307 to a wall. Fig. 10 also schematically depicts an embodiment of an outdoor light, or stage light, or stadium light. Fig. 10 also schematically depicts a vehicle, like an automobile, but this may also be a truck, a motor cycle, etc. etc., with automotive lighting 4, e.g. headlights. These automotive lighting 4 may also comprise the lighting device 1200. Another embodiment of a lamp may be a torch.

[0302] 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%, such as > 95%, especially > 99%, like > 99.5%, including 100%.

[0303] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0304] Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

Claims

2025PF8004369CLAIMS:

1. A light generating system (1000) comprising a blueish light generating device (120), a diffuser light generating device (130), optics (500), a diffuser assembly (700), and a light exit (1090); wherein:the blueish light generating device (120) is configured to provide blueish device light (121) having a blueish centroid wavelength (λc2) selected from the wavelength range of 430-490 nm, wherein the blueish light generating device (120) comprises a blueish solid state light source (20);the diffuser light generating device (130) is configured to provide diffuser device light (131) having a diffuser centroid wavelength (λc3) selected from the wavelength range of 470-780 nm, wherein the diffuser light generating device (130) comprises a diffuser solid state light source (30); wherein |Xc3-Xc2| > 10 nm;the blueish and diffuser solid state light sources (20,30) are individually selected from the group comprising laser diodes, superluminescent diodes, and stacked multijunction light-emitting diodes;the optics (500) comprise a diffuser redirection optical element (530);the diffuser redirection optical element (530) is configured (i) in an optical path between the blueish light generating device (120) and the diffuser assembly (700) and (ii) in an optical path between the diffuser light generating device (130) and the diffuser assembly (700); wherein the diffuser redirection optical element (530) is configured (i) to direct blueish device light (121), received by the diffuser redirection optical element (530), into an optical path to the diffuser assembly (700), and (ii) to direct diffuser device light (131), received by the diffuser redirection optical element (530), into an optical path to the diffuser assembly (700);the diffuser assembly (700) comprises a diffuser (710) configured to diffuse at least part of the blueish device light (121), received by the diffuser assembly (700) via the diffuser redirection optical element (530), into diffused blueish device light (721), and at least part of the diffuser device light (131), received by the diffuser assembly (700) via the diffuser redirection optical element (530), into diffused diffuser device light (731);2025PF8004370the diffuser redirection optical element (530) is further configured to: (i) direct the diffused blueish device light (721), received by the diffuser redirection optical element (530), into an optical path to the light exit (1090), and (ii) direct the diffused diffuser device light (731), received by the diffuser redirection optical element (530), into an optical path to the light exit (1090); wherein (i) an optical axis of the blueish device light (121) upstream of the diffuser redirection optical element (530), and (ii) an optical axis of the diffused blueish device light (721) and the diffused diffuser device light (731) downstream of the diffuser redirection optical element (530) are co-axial; wherein the light generating system (1000) is configured such, that the blueish device light (121) and the diffuser device light (131) are incident on the diffuser redirection optical element (530) from orthogonal directions; and the light generating system (1000) is configured to generate system light (1001), wherein in a first operational mode of the light generating system (1000), the system light (1001) comprises at least part of the diffused blueish device light (721) and at least part of the diffused diffuser device light (731).

2. The light generating system (1000) according to claim 1, wherein one or more of the following applies:the diffuser (710) is configured in the reflective mode, wherein the diffuser assembly (700) is configured such that an optical axis of the blueish and diffuser device light (121,131) reaching the diffuser (710) and an optical axis of the diffused blueish and diffuser device light (721,731) reflecting from the diffuser (710) are co-axial; wherein the diffuser assembly (700) comprises a polarization converter (720) configured in an optical path between the diffuser redirection optical element (530) and the diffuser (710); wherein the polarization converter (720) is configured to convert (i) device light comprising one of the first linear polarization and a second linear polarization, different from the first linear polarization, into device light comprising an elliptical polarization, and (ii) diffused device light comprising an elliptical polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization;the diffuser (710) is configured in the reflective mode, wherein the diffuser assembly (700) is configured such that an optical axis of the blueish and diffuser device light (121,131) reaching the diffuser (710) and an optical axis of the diffused blueish and diffuser device light (721,731) reflecting from the diffuser (710) are not co-axial; wherein the diffuser assembly (700) further comprises an assembly polarization converter (750) configured in an optical path between the diffuser redirection optical element (530) and the diffuser (710);2025PF8004371wherein the assembly polarization converter (750) is configured to convert (i) device light comprising one of the first linear polarization and the second linear polarization into device light comprising the other one of the first linear polarization and the second linear polarization, and (ii) diffused device light comprising one of the first linear polarization and the second linear polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization; wherein the light generating system (1000) comprises a plurality of reflectors (560) configured to (i) reflect device light received from the diffuser redirection optical element (530) in an optical path to the diffuser assembly (700) and / or (ii) reflect diffused device light received from the diffuser (710) in an optical path to the diffuser redirection optical element (530); andthe diffuser (710) is configured in the transmissive mode; wherein the diffuser assembly (700) further comprises an assembly polarization converter (750) configured in an optical path between the diffuser redirection optical element (530) and the diffuser (710); wherein the assembly polarization converter (750) is configured to convert (i) device light comprising one of a first linear polarization and a second linear polarization into device light comprising the other one of the first linear polarization and the second linear polarization, and (ii) diffused device light comprising one of the first linear polarization and the second linear polarization into diffused device light comprising the other one of the first linear polarization and the second linear polarization; wherein the light generating system (1000) comprises a plurality of reflectors (560) configured to (i) reflect device light received from the diffuser redirection optical element (530) in an optical path to the diffuser assembly (700) and / or (ii) reflect diffused device light emitted by the diffuser (710) in an optical path to the diffuser redirection optical element (530).

3. The light generating system (1000) according to any one of the preceding claims, wherein the diffuser redirection optical element (530) comprises a polarizing beam splitter configured to, in dependence of their respective polarizations:reflect three types of light and transmit one type of light, wherein the types of light are selected from the group consisting of (i) blueish device light (121) received by the diffuser redirection optical element (530) from the blueish light generating device (120), (ii) diffused blueish device light (721) received by the diffuser redirection optical element (530) from the diffuser assembly (700), (iii) diffuser device light (131) received by the diffuser redirection optical element (530) from the diffuser light generating device (130), and (iv)2025PF8004372diffused diffuser device light (731) received by the diffuser redirection optical element (530) from the diffuser assembly (700); ortransmit three types of light and reflect one type of light, wherein the types of light are selected from the group consisting of: (i) blueish device light (121) received by the diffuser redirection optical element (530) from the blueish light generating device (120), (ii) diffused blueish device light (721) received by the diffuser redirection optical element (530) from the diffuser assembly (700), (iii) diffuser device light (131) received by the diffuser redirection optical element (530) from the diffuser light generating device (130), and (iv) diffused diffuser device light (731) received by the diffuser redirection optical element (530) from the diffuser assembly (700).

4. The light generating system (1000) according to any one of the preceding claims, wherein the diffuser (710) is a polarization maintaining diffuser for at least one of the blueish device light (121) and the diffuser device light (131); wherein the light generating system (1000) is configured such, that the at least one of the blueish device light (121) and the diffuser device light (131) received by the diffuser redirection optical element (530) comprises one of the first linear polarization and the second linear polarization as defined in claim 2.

5. The light generating system (1000) according to any one of the preceding claims 2-4, wherein the diffuser (710) is configured in the transmissive mode, wherein one of the following applies:an optical axis (0,2 of the blueish device light (121) reaching the diffuser (710) and an optical axis (Ois) of the diffuser device light (131) reaching the diffuser (710) are parallel; wherein an optical axis (Ot2) of the diffused blueish device light (721) emanating away from the diffuser (710) and an optical axis (Oo) of the diffused diffuser device light (731) emanating away from the diffuser (710) are parallel; andan optical axis (0,2 of the blueish device light (121) reaching the diffuser (710) and an optical axis (Ois) of the diffuser device light (131) reaching the diffuser (710) are antiparallel; wherein an optical axis (Ot2) of the diffused blueish device light (721) emanating away from the diffuser (710) and an optical axis (Oo) of the diffused diffuser device light (731) emanating away from the diffuser (710) are antiparallel.2025PF80043736. The light generating system (1000) according to any one of the preceding claims 2-4, wherein the diffuser (710) is configured in the reflective mode, wherein the optical axis of the device light reaching the diffuser (710) and the optical axis of the diffused device light reflecting from the diffuser (710) are not co-axial; wherein one of the following applies:an optical axis (0,2 of the blueish device light (121) reaching the diffuser (710) and an optical axis (Ois) of the diffuser device light (131) reaching the diffuser (710) are parallel; wherein an optical axis (Ot2) of the diffused blueish device light (721) emanating away from the diffuser (710) and an optical axis (Oo) of the diffused diffuser device light (731) emanating away from the diffuser (710) are parallel; andan optical axis (0,2 of the blueish device light (121) reaching the diffuser (710) and an optical axis (Oo) of the diffused diffuser device light (731) emanating away from the diffuser (710) are antiparallel; wherein an optical axis (Ot2) of the diffused blueish device light (721) emanating away from the diffuser (710) and an optical axis (0,3 of the diffuser device light (131) reaching the diffuser (710) are antiparallel.

7. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) further comprises a luminescent material (200); wherein the optics (500) further comprise a second redirection optical element (520); wherein:the second redirection optical element (520) is configured in an optical path between the blueish light generating device (120) and the diffuser redirection optical element (530); wherein the second redirection optical element (520) comprises a polarizing beam splitter; wherein the second redirection optical element (520) is configured to direct the blueish device light (121), received by the second redirection optical element (520), into an optical path to the luminescent material (200) and / or the diffuser assembly (700) in dependence of its linear polarization;the luminescent material (200) is configured to convert at least part of the blueish device light (121), received by the luminescent material (200) via the second redirection optical element (520), into luminescent material light (201), wherein the luminescent material light (201) has a luminescent material centroid wavelength ( imc), wherein |X<;3-Ximc| > 10 nm; andin a first operational mode of the light generating system (1000), the system light (1001) is white light comprising at least part of the luminescent material light (201), at2025PF8004374least part of the diffused blueish device light (721), and at least part of the diffused diffuser device light (731).

8. The light generating system (1000) according to claim 7, wherein the second redirection optical element (520) is further configured in an optical path between the diffuser redirection optical element (530) and the light exit (1090); wherein the second redirection optical element (520) is configured to direct the luminescent material light (201), the diffused blueish device light (721), and the diffused diffuser device light (731), received by the second redirection optical element (520), into an optical path to the light exit (1090); wherein the luminescent material centroid wavelength ( imc) is selected from the range of 500-600 nm; wherein the second redirection optical element (520) comprises a multichroic beam combiner, wherein the multichroic beam combiner is configured to one or more of:transmit light received by the second redirection optical element (520) and having one of (i) a wavelength below a first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cut-off wavelength (Xcoi), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi), and (ii) a wavelength above the first cut-off wavelength (Xcoi); wherein + 5 nm < Xcoi < Ximc - 10 nm;transmit light received by the second redirection optical element (520) and having one of (i) a wavelength below a second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the second cut-off wavelength (Xco2), and (ii) a wavelength above the second cut-off wavelength ( co2); wherein Ximc+ 10 nm < Xc<>2 < 3 - 5 nm;transmit light received by the second redirection optical element (520) and having one of (i) a wavelength below a first cut-off wavelength (Xcoi) and above a second cutoff wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and above the second cut-off wavelength (Xco2), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (^02); wherein Xc2 + 5 nm < Xcoi < +imc - 10 nm and Ximc + 10 nm < >^<>2 < 3 - 5 nm;transmit light received by the second redirection optical element (520) and having one of (i) a wavelength below a second cut-off wavelength (Xco2) and above a third2025PF8004375cut-off wavelength (Xcos), and (ii) a wavelength between the second cut-off wavelength (>^<>2) and the third cut-off wavelength (Xcos), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xcos), and (ii) a wavelength between the second cut-off wavelength (Xco2) and the third cut-off wavelength (>^<>3); wherein imc + 10 nm < Xco2 < Xc3 - 5 nm and Xc<>3 > 3 + 5 nm; andtransmit light received by the second redirection optical element (520) and having one of (i) a wavelength below a first cut-off wavelength (Xcoi) and between a second cut-off wavelength (Xco2) and a third cut-off wavelength (Xcos), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xc<>2 and above the third cut-off wavelength (Xcos), and reflect light received by the second redirection optical element (520) and having the other of (i) a wavelength below the first cut-off wavelength (Xcoi) and between the second cut-off wavelength (Xc<>2 and the third cut-off wavelength (Xco3), and (ii) a wavelength between the first cut-off wavelength (Xcoi) and the second cut-off wavelength (Xco2) and above the third cut-off wavelength (Xcos); wherein + 5 nm < XcOi< Ximc - 10 nm, Ximc + 10 nm < >^<>2 < 3 - 5 nm and > <>3 > 3 + 5 nm.

9. The light generating system (1000) according to claim 8, wherein the diffuser redirection optical element (530) is configured in an optical path between the luminescent material (200) and second redirection optical element (520); wherein the diffuser redirection optical element (530) is configured to direct the luminescent material light (201), received by the diffuser redirection optical element (530), into an optical path to the second redirection optical element (520); wherein the light generating system (1000) is configured such, that (i) the luminescent material light (201), and (ii) the diffused blueish device light (721) and diffused diffuser device light (731) are incident on the diffuser redirection optical element (530) from orthogonal directions.

10. The light generating system (1000) according to any one of claims 7-8, wherein the optics (500) further comprise a combiner redirection optical element (510); wherein the combiner redirection optical element (510) is configured (i) in an optical path between the luminescent material (200) and the light exit (1090), and (ii) in an optical path between the diffuser redirection optical element (530) and the light exit (1090); wherein the combiner redirection optical element (510) comprises a multi chroic beam splitter; wherein the combiner redirection optical element (510) is configured to direct the luminescent2025PF8004376material light (201), the diffused blueish device light (721), and the diffused diffuser device light (731), received by the combiner redirection optical element (510), into an optical path to the light exit (1090); wherein the light generating system (1000) is configured such, that the luminescent material light (201) and the diffused device light are incident on the combiner redirection optical element (510) from orthogonal directions.

11. The light generating system (1000) according to any one of the preceding claims 7-10, wherein the light generating system (1000) is configured such that the blueish device light (121) reaching the second redirection optical element (520) comprises a controllable polarization; wherein the light generating system (1000) comprises a control system (300) and a polarization control system (600); wherein the polarization control system (600) is configured to control the polarization of the blueish device light (121) reaching the second redirection optical element (520); and wherein the control system (300) is configured to control one or more of a spectral power distribution, a correlated color temperature, a color gamut, and a color rendering index of the system light (1001) by controlling the polarization control system (600).

12. The light generating system (1000) according to any one of the preceding claims 7-11, wherein the light generating system (1000) further comprises a pump light generating device (110), wherein:the pump light generating device (110) is configured to provide pump device light (111) having a pump centroid wavelength (Xci) selected from the wavelength range of 430-490 nm, wherein the pump light generating device (110) comprises a pump solid state light source (10) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes;the pump light generating device (110) is configured upstream of one of (i) the combiner redirection optical element (510) as defined in claim 10, and (ii) the second redirection optical element (520); wherein the one of (i) the combiner redirection optical element (510) and (ii) the second redirection optical element (520) is configured to direct the pump device light (111), received by the redirection optical element, into an optical path to the luminescent material (200); andthe luminescent material (200) is configured to convert at least part of the pump device light (111), received by the luminescent material (200), into luminescent material light (201).2025PF800437713. The light generating system (1000) according to claim 12, wherein the pump light generating device (110) is configured upstream of the second redirection optical element (520); wherein the optics (500) comprise a second combiner redirection optical element (540); wherein the second combiner redirection optical element (540) comprises a multichroic beam splitter or a geometric beam splitter; wherein the second combiner redirection optical element (540) is configured (i) in an optical path between the blueish light generating device (120) and the second redirection optical element (520), and (ii) in an optical path between the pump light generating device (110) and the second redirection optical element (520); wherein the light generating system (1000) is configured such, that the pump device light (111) and the blueish device light (121) are incident on the second combiner redirection optical element (540) from orthogonal directions; and wherein the second combiner redirection optical element (540) is configured to direct the pump device light (111) and the blueish device light (121), received by the second combiner redirection optical element (540), into an optical path to the second redirection optical element (520).

14. The light generating system (1000) according to any one of the preceding claims 7-13, further comprising a fourth light generating device (140) and a fifth redirection optical element (550); wherein the fourth light generating device (140) is configured upstream of the fifth redirection optical element (550); wherein the fourth light generating device (140) is configured to provide fourth device light (141) having a fourth centroid wavelength (λc4) selected from the wavelength range of 430-510 nm; wherein the fourth light generating device (140) comprises a fourth solid state light source (40) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction lightemitting diodes; wherein one of the following applies:the fifth redirection optical element (550) is configured in an optical path between the second redirection optical element (520) and the luminescent material (200); wherein the fifth redirection optical element (550) is configured to direct the blueish device light (121) and the fourth device light (141), received by the fifth redirection optical element (550), into an optical path to the luminescent material (200); wherein the luminescent material (200) is configured to convert at least part of the fourth device light (141), received by the luminescent material (200), into luminescent material light (201); andthe fifth redirection optical element (550) is configured in an optical path between the pump light generating device (110) as defined in claim 12 and the second2025PF8004378combiner redirection optical element (540) as defined in claim 13; wherein the fifth redirection optical element (550) is configured to direct the pump device light (111) and the fourth device light (141), received by the fifth redirection optical element (550), into an optical path to the second combiner redirection optical element (540); wherein the second redirection optical element (520) is configured to direct the fourth device light (141), received by the second redirection optical element (520), into an optical path to one or more of (a) the luminescent material (200), wherein the luminescent material (200) is configured to convert at least part of the fourth device light (141), received by the luminescent material (200), into luminescent material light (201); and (b) the diffuser assembly (700), wherein the diffuser (710) is configured to diffuse the fourth device light (141), received by the diffuser assembly (700), into diffused fourth device light (741), and wherein, in an operational mode of the light generating system (1000), the system light (1001) comprises the diffused fourth device light (741).

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

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