Tunable laser-phosphor engine with spectrally enhanced blue channel

Abstract

The invention provides a light generating system (1000) comprising light generating devices (100), a luminescent material arrangement (2000), a diffuser arrangement (7000), optics (500), a control system (300), and a light exit (1090); wherein: (A) the light generating devices (100) comprise (i) a first light generating device (110) configured to generate first device light (111), and (ii) a second light generating device (120) configured to generate second device light (121); (B) the luminescent material arrangement (2000) comprises a luminescent material (200) configured to convert at least part of first device light (111) received by the luminescent material (200) into luminescent material light (201); (C) the diffuser arrangement (7000) comprises a diffuser (700) configured to diffuse second device light (121) and first device light (111) received by the diffuser (700) into diffused device light (701); (D) the optics (500) comprise a first polarization based redirecting optical element (511) configured downstream of the first light generating device (110) and upstream of both the luminescent material arrangement (2000) and the diffuser arrangement (7000); (E) the optics (500) comprise a first multichroic based redirecting optical element (521) configured (a) in an optical path between the first polarization based redirecting optical element (511) and the diffuser arrangement (7000) and (b) in an optical path between the second light generating device (120) and the diffuser arrangement (7000); (F) the optics (500) comprise a second multichroic based redirecting optical element (522) configured (a) in an optical path between the first polarization based redirecting optical element (511) and the luminescent material arrangement (2000), (b) in an optical path between the luminescent material arrangement (2000) and the light exit (1090), and (c) in an optical path between the diffuser arrangement (7000) and the light exit (1090); and (G) the light generating system (1000) is configured to provide, via the light exit (1090), system light (1001); wherein the control system (300) is configured to control the system light (1001); wherein the system light (1001) in a first operational mode of the light generating system (1000) comprises at least part of the luminescent material light (201) and at least part of the diffused device light (701).

Description

[0001] 2024PF80240

[0002] 1

[0003] Tunable laser-phosphor engine with spectrally enhanced blue channel

[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] Laser-phosphor based stage lighting fixtures are known in the art. For instance, WO2022143318 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 light mixing effect of emergent light can be improved by using the first scattering optical system. Light emitted by the first light source is all used for exciting the wavelength conversion apparatus.

[0008] SUMMARY OF THE INVENTION

[0009] High brightness light sources can be used in various applications including spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. For this purpose, laser-phosphor technology can be used, wherein a laser provides laser light and a remote phosphor converts laser light into converted light. A relatively straightforward way to produce white light using lasers is to use (blue) laser light in combination with a (yellow) phosphor to generate phosphor converted light. Laser-phosphor systems may allow generation of high brightness light and may therefore be used in projection systems, including displays such as cinema projectors and projectors for home, school, and office applications, car front lighting, search lighting, stage lighting, architectural lighting, and special lighting applications. In general, a laser-phosphor light engine may be capable to generate only a single color point as defined by the luminescent converter. Creation of a product range providing different color points may be costly as it requires 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 is limited by the components used, the engine volume is large due to the many components, and the system cost are high 2024PF80240

[0010] 2 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, which may result in relatively high losses of diffused blue light at a beam combiner where it is combined with the luminescent light into white output light.

[0011] In many laser-based light engine designs the effective usage of the laser light sources, in case there is more than one source, may depend on the light source design (what is the maximum output of the sources used) in relation to the targeted output power and the color point of the (white) light output. There appears to be 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 is very limited and installation of redundant laser diodes is very expensive. In addition, there may be a need to increase both the color rendering properties of laser-based light engines, as well as the color gamut properties. However, a system comprising a first laser source fully used for light conversion and a second laser source that may partly be used for luminescent conversion and partly be used to contribute as blue light to the output white light, may not be a viable solution, as e.g. entertainment lighting may request higher light output values than what can be realized with the highest power laser banks that are available on the market. Therefore, there appears to be a need for tunable laser-phosphor light engines that make more efficient use 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 improved color gamut and color rendering properties. For applications like stage lighting, there may be a dedicated range of blue flux in the output white light requested to cover the beam, spot and wash applications with a single fixture, while for spot and wash applications a relatively low CCT may be requested with improved color rendering.

[0012] 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 (“system”) comprising light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, and a light exit. Further, in embodiments the light generating system may comprise a control system. In embodiments, the light generating devices may 2024PF80240

[0014] 3 comprise (i) a first light generating device configured to generate first device light, and (ii) a second light generating device configured to generate second device light. Further, in specific embodiments the first light generating device and the second light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode. In embodiments, the luminescent material arrangement comprises a luminescent material configured to convert at least part of (first) device light received by the luminescent material into luminescent material light. Yet, in embodiments the diffuser arrangement may comprises a diffuser configured to diffuse device light received by the diffuser into diffused device light. For instance, the diffuser may receive second device light and (optionally) first device light. In embodiments, the optics may comprise a first polarization based redirecting optical element configured downstream of the first light generating device and upstream of both the luminescent material arrangement and the diffuser arrangement. Yet, in specific embodiments the light generating system may be configured such that the first device light received by the first polarization based redirecting optical element comprises linear polarized light. Further, in specific embodiments the first polarization based redirecting optical element may be configured to direct first device light in dependence of its (linear) polarization to one or more of the luminescent material arrangement and the diffuser arrangement. Yet, in embodiments the optics may (further) comprise a first multichroic based redirecting optical element configured (a) in an optical path between the first polarization based redirecting optical element and the diffuser arrangement and (b) in an optical path between the second light generating device and the diffuser arrangement. In specific embodiments, the first multichroic based redirecting optical element may be configured to direct (i) first device light received via the first polarization based redirecting optical element, and (ii) second device light received from the second light generating device in an optical path to the diffuser arrangement. Yet, in embodiments the optics may (further) comprise a second multichroic based redirecting optical element configured (in one or more of) (a) in an optical path between the first polarization based redirecting optical element and the luminescent material arrangement, (b) in an optical path between the luminescent material arrangement and the light exit, and (c) in an optical path between the diffuser arrangement and the light exit. In specific embodiments, the second multichroic based redirecting optical element may be configured to direct (i) luminescent material light, received by the second multichroic based redirecting optical element, and (ii) diffused device light, received by the second multichroic based redirecting optical element, in an (mutual) optical path to the light exit. In embodiments, the light generating system may be 2024PF80240

[0015] 4 configured to provide, via the light exit, system light. In specific embodiments, the control system may be configured to control the system light. Yet, in specific embodiments the system light in a first operational mode of the light generating system may comprise at least part of the luminescent material light and at least part of the diffused device light, and may have in further specific embodiments one or more of (a) a correlated color temperature selected from the range of 1800-12000 K and (b) a CRI selected from the range of at least 65. Hence, in specific embodiments the invention provides a light generating system comprising light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, a control system, and a light exit; wherein: (A) the light generating devices comprise (i) a first light generating device configured to generate first device light, (ii) a second light generating device configured to generate second device light, and (iii) a third light generating device configured to generate third device light; wherein the first light generating device, the second light generating device, and the third light generating device comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode; (B) the luminescent material arrangement comprises a luminescent material configured to convert at least part of first device light received by the luminescent material into luminescent material light; (C) the diffuser arrangement comprises a diffuser configured to diffuse second device light and first device light received by the diffuser into diffused device light; wherein incoming light, comprising second device light and optional first device light and / or third device light, on the diffuser, has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser, and wherein outgoing diffused device light has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser, wherein the optical axes (Oi,Oo) have a mutual angle (P) unequal to 0°; (D) the optics comprise a first polarization based redirecting optical element configured downstream of the first light generating device and upstream of both the luminescent material arrangement and the diffuser arrangement; wherein the light generating system is configured such that the first device light received by the first polarization based redirecting optical element comprises linear polarized light; wherein the first polarization based redirecting optical element is configured to direct first device light in dependence of its (linear) polarization to one or more of the luminescent material arrangement and the diffuser arrangement; (E) the optics (further) comprise a first multichroic based redirecting optical element configured (a) in an optical path between the first polarization based redirecting optical element and the diffuser arrangement and (b) in an optical path between the second light generating device and the diffuser arrangement; wherein the first multichroic based redirecting optical element is configured to direct (i) first 2024PF80240

[0016] 5 device light received via the first polarization based redirecting optical element, and (ii) second device light received from the second light generating device in an optical path to the diffuser arrangement; (F) the optics comprise a second multichroic based redirecting optical element configured (a) in an optical path between the first polarization based redirecting optical element and the luminescent material arrangement, (b) in an optical path between the luminescent material arrangement and the light exit, and (c) in an optical path between the diffuser arrangement and the light exit; wherein the second multichroic based redirecting optical element is configured to direct (i) luminescent material light, received by the second multichroic based redirecting optical element, and (ii) diffused device light, received by the second multichroic based redirecting optical element, in an (mutual) optical path to the light exit; and (G) the light generating system is configured to provide, via the light exit, system light; wherein the control system is configured to control the system light; wherein the system light in a first operational mode of the light generating system comprises at least part of the luminescent material light and at least part of the diffused device light, and has a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

[0017] Amongst others, this invention may provide light engine architectures that can be operated with three or more laser banks of which the output of at least one laser banks can adjustably be redistributed over the conversion and the diffusion channel, where the color rendering may be improved by using a largest fraction of the diffused blue light at a longer wavelength than the center wavelength of the laser light that is used for luminescent conversion, and where optionally in specific embodiments additional red laser light may be mixed into the diffusion channel to be diffused together with the blue laser light without requiring an additional reflective diffuser assembly. With such system, a high power light generating system may be provided. Further, such system may allow control of spectral power distribution of the system light (of a high power system), in dependence of the controllable polarization of light.. Yet, such system may in a safe way provide high power light. The system may be relatively compact. Yet, thermal management of the luminescent material may also be provided with this system. In addition to high optical power, the system may also provide high radiance (or luminance), i.e., a high optical power density of the source. The current invention also allows improving stage lighting fixtures.

[0018] The light generating system (or “system”) may thus comprise light generating devices, a luminescent material arrangement, a diffuser arrangement, optics, a control system, 2024PF80240

[0019] 6 and a light exit. Here below, embodiments of the different components of the light generating system will be described in further detail.

[0020] The light generating devices may be configured to generate device light. In embodiments, the light generating devices may comprise (at least) a first light generating device and a second light generating device.

[0021] The first light generating device may, in embodiments, be configured to generate first device light. Therefore, in embodiments, the first light generating device may comprise a first light source. The first light source may be essentially any light source, see also further below. Especially, in embodiments, the (first light source of the) first light generating device may comprise a first solid state light source. Hence, in embodiments, the first light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The first light generating device may herein also comprise a plurality of first (solid state) light sources. Especially, in specific embodiments, the first light generating device may comprise a first laser bank comprising a plurality of first lasers. A laser bank may comprise a relatively dense assembly of multiple laser diodes on a shared substrate provided with collimating optics, such as collimating lenses comprising one lens per laser diode. The use of laser banks may especially be convenient for projecting a beam of high power laser light onto a luminescent converter without the need for using an inverse beam expander.

[0022] Further, in embodiments, the first light generating device may especially be configured to generate first device light having a first peak wavelength (Xpi). Especially, in embodiments, the first device light may have a first peak wavelength (Xpi) selected from the wavelength range of 380-490 nm, such as especially selected from the wavelength range of 430-490 nm, such as from the range of 440-480 nm, like from the range of 445-475 nm. Hence, in embodiments, the first device light may be blue light.

[0023] Analogously to the first light generating device, in embodiments, the second light generating device may be configured to generate second device light. Therefore, in embodiments, the second light generating device may comprise a second light source. The second light source may be essentially any light source, see also further below. Especially, in embodiments, the (second light source of the) second light generating device may comprise a second solid state light source. Hence, in embodiments, the second light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode (LED). In embodiments, the second light generating device may comprise essentially the same light generating device as the first light generating device. 2024PF80240

[0024] 7

[0025] However, in other embodiments, the first light generating device and the second light generating device may be substantially different. The second light generating device may herein also comprise a plurality of second (solid state) light sources. Especially, in specific embodiments, the second light generating device may comprise a second laser bank comprising a plurality of second lasers.

[0026] Further, in embodiments, the second light generating device may especially be configured to generate second device light having a second peak wavelength (Xp2). Especially, in embodiments, the second device light may have a second peak wavelength (Xp2) selected from the wavelength range of 380-780 nm, such as in embodiments selected from the wavelength range of 380-490 nm, especially selected from the wavelength range of 430-490 nm, such as from the range of 440-480 nm, like from the range of 445-475 nm. Hence, in specific embodiments, the second device light may be blue light. Whereas in embodiments, the second device light may essentially exist of light having spectral intensity in the 430-490 nm wavelength range, such at least 80%, like at least 90% of the spectral power in this wavelength range, it is herein not excluded that in other embodiments the second device light has a peak wavelength in another wavelength range, such as in the orange wavelength range or in the red wavelength range, or that in more specific embodiments, the second device light may consist of light having multiple peaks, such as one in the blue wavelength range, and one in the red wavelength range. Hence, in other specific embodiments, the second device light may comprise one or more of blue light and red light (see also below).

[0027] Hence, in embodiments the light generating devices may comprise (i) a first light generating device configured to generate first device light, and (ii) a second light generating device configured to generate second device light; wherein the first light generating device and the second light generating device comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode.

[0028] In embodiments, the first light generating device and the second light generating device may be configured to provide first device light and second device light, respectively, to the optics.

[0029] The optics may, in embodiments, comprise a first polarization based redirecting optical element. In embodiments, (in an operational mode of the light generating system) the first polarization based redirecting optical element may be configured downstream of the first light generating device. In other words, in embodiments, in an operational mode of the light generating system the first polarization based redirecting optical 2024PF80240

[0030] 8 element may be configured in a light-receiving relationship with the first light generating device. The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”.

[0031] In embodiments, the device light received by the first polarization based redirecting optical element may especially be polarized light. Hence, in embodiments, the light generating system may be configured such that the first device light received by the first polarization based redirecting optical element may comprise polarized light. In embodiments, the first device light received by the first polarization based redirecting optical element may especially comprise linearly polarized first device light, such as e.g. p-polarized first device light and / or s-polarized first device light. The first light generating device may, in embodiments, be configured to provide (linearly) polarized first device light. Additionally or alternatively, in embodiments, the first device light may be unpolarized light and the polarization control system (see also further below) may be configured such that (linearly) polarized first device light may be provided to the first polarization based redirecting optical element. In such embodiments, the polarization control system may especially comprise a polarizer configured to change the polarization of device light received by the polarizer. For example, in embodiments, the first light generating device may be configured to generate first device light comprising a circular polarization and to provide said circularly polarized first device light to the polarizer (such as e.g. a X / 4 waveplate). In such embodiments, the polarizer may be configured to convert the circularly polarized first device light into first device light comprising a ratio of first device light comprising the first linear polarization relative to first device light comprising the second linear polarization.

[0032] The phrase “... light received by ...”, and similar phrases, such as “device light received by the first polarization based redirecting optical element” may especially indicate that when the light is actually received by an item, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. Further, the action may also include refraction. Whether or not such item receives light may e.g. depend on e.g. a controlling mode (for instance whether or not a light generating device provides light). 2024PF80240

[0033] 9

[0034] With reference to the first polarization based redirecting optical element, but also to other polarization based redirecting optical elements mentioned herein, the following general embodiments are described.

[0035] A polarizing beam splitter may be considered an example of (polarization based) redirecting optics or (polarization based) redirecting optics. Light propagating to the polarizing beam splitter, and comprising both linear polarizations, like elliptically polarized light, may be split in two orthogonally propagating beams of light with complementary linear polarizations. Hence, this provides the polarizing beam splitter its beam splitting function. 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, a polarizing beam splitter may also be indicated as a polarizing beam combiner.

[0036] Hence, for the polarizing beam splitter may apply that for a first polarization, the transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30 % points, than for a second polarization. Similarly, for a first polarization, the reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30 % points, than for a second polarization. Especially, in embodiments, the polarizing beam splitter may be configured to direct at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the first polarization to a first direction and at least 60%, like at least 80%, more especially at least 90%, such as at least about 95%, of the light of the second polarization to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45- 135°, such as about 90°. The percentage of the light may refer to a spectral power (e.g. in Watt). Especially, the first polarization and the second polarization may comprise linear polarizations such as selected from s polarization and p polarization. Optionally, the first polarization and the second polarization may be selected from different elliptically polarized light. In embodiments, the polarizing beam splitters herein may be selected from reflective polarizing beam splitters (reflective polarizers).

[0037] Hence, especially in the current invention, in embodiments the optics may (thus) comprise a first polarization based redirecting optical element configured downstream of the first light generating device and upstream of both the luminescent material arrangement and the diffuser arrangement. In embodiments, the light generating system may 2024PF80240

[0038] 10 be configured such that the first device light received by the first polarization based redirecting optical element comprises linear polarized light. Especially, in embodiments the first polarization based redirecting optical element may be configured to direct first device light in dependence of its (linear) polarization to one or more of the luminescent material arrangement and the diffuser arrangement. More especially, the first polarization based redirecting optical element may be configured to direct first device light in dependence of the orientation of its linear polarization components to one or more of the luminescent material arrangement and the diffuser arrangement.

[0039] The first polarization based redirecting optical element may be configured to distribute first device light over an optical path to the luminescent material arrangement and another optical path to the diffuser arrangement. This distribution of the first device light over these two channels may be a fixed distribution, such as factory set distribution, or may be a controllable distribution, by using the polarization control system (see also below).

[0040] Basically, the distribution can be anything between 0% to one channel and 100% to the other channel, and 100% to the one channel and 0% to the other channel. There are several options to choose the distribution of the first device light over these two channels. On the one hand, the polarization of the first device light reaching the first polarization based redirecting optical element is an input parameter defining the distribution and on the other hand the specifications of the first polarization based redirecting optical element are another input parameter defining the distribution.

[0041] As indicated above, in relation to the former, the polarization of the first device light reaching the first polarization based redirecting optical element may be factory set or may be controllable.

[0042] In relation to the specifications of the first polarization based redirecting optical element it is noted that in embodiments the first polarization based redirecting optical element may be a polarizing beam splitter which may essentially fully separate the different linear polarizations, i.e. p-polarized (device) light received by the first polarization based redirecting optical element is directed in one direction and s-polarized (device) light is directed in another direction (orthogonal to the one direction). However, in other embodiments that the first polarization based redirecting optical element may be a polarizing beam splitter which may partly separate the different linear polarizations, i.e. p-polarized (device) light received by the first polarization based redirecting optical element may be directed in two (orthogonal) directions and / or s-polarized (device) light may be directed in the same two (orthogonal) directions. In specific embodiments, the ratios of s-polarized light 2024PF80240

[0043] 11 and p-polarized light in the different directions differ, such as in one direction essentially only one of the s-polarized light and p-polarized light is directed, and in the other (orthogonal) direction, both s-polarized light and p-polarized light are directed. Hence, in embodiments the first polarization based redirecting optical element may be partly transmissive and partly reflective for one of the linear polarizations and fully transmissive for the other of the linear polarizations, and in other embodiments the first polarization based redirecting optical element may be partly reflective and partly transmissive for one of the linear polarizations and fully reflective for the other of the linear polarizations. In this way, (also) this distribution of the first device light over these two channels (i.e. to the optical paths to the luminescent material arrangement and the diffuser arrangement) may be selected. Here below, some specific embodiments are described. General aspects in relation to the first polarization based redirecting optical element may also apply to other polarization based redirecting optical element that may be applied in the current invention.

[0044] As indicated above, the first polarization based redirecting optical element may be configured upstream of the luminescent material arrangement. Additionally or alternatively, in embodiments, the first polarization based redirecting optical element may (also) be configured upstream of the diffuser arrangement. Especially, in embodiments, in an operational mode of the light generating system the first polarization based redirecting optical element may be configured upstream of both the luminescent material arrangement and the diffuser arrangement. As such, in embodiments, the luminescent material arrangement and the diffuser arrangement may both be configured in a light-receiving relationship with the first polarization based redirecting optical element. Especially, in embodiments, the first polarization based redirecting optical element may be configured to direct device light to the luminescent material arrangement and the diffuser arrangement.

[0045] In embodiments, the first polarization based redirecting optical element may be configured to transmit or reflect (device) light in dependence of its polarization. Especially, in embodiments, the first polarization based redirecting optical element may be configured to transmit (device) light received by the first polarization based redirecting optical element and (said (device) light) comprising a first linear polarization. Especially, in embodiments, the first polarization based redirecting optical element may be configured to transmit at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the first linear polarization) received by the first polarization based redirecting optical element. Further, in such embodiments, the first polarization based redirecting optical element may be configured to 2024PF80240

[0046] 12 reflect light received by the first polarization based redirecting optical element and (said (device) light) comprising a second linear polarization. Especially, in embodiments, the first polarization based redirecting optical element may be configured to reflect at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the second linear polarization) received by the first polarization based redirecting optical element. Alternatively, in embodiments, the first polarization based redirecting optical element may be configured to reflect light received by the first polarization based redirecting optical element and (said (device) light) comprising the first linear polarization. Especially, in embodiments, the first polarization based redirecting optical element may be configured to reflect at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the first linear polarization) received by the first polarization based redirecting optical element. Further, in such embodiments, the first polarization based redirecting optical element may be configured to transmit light received by the first polarization based redirecting optical element and (said (device) light) comprising the second linear polarization. Especially, in embodiments, the first polarization based redirecting optical element may be configured to transmit at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95%, including 100% of the light (comprising the second linear polarization) received by the first polarization based redirecting optical element. Note that, in embodiments, the first polarization based redirecting optical element may also function as a beam combiner (e.g. configured to combine (along a same optical path) a part of the first device light with the second device light).

[0047] In embodiments, the second linear polarization may especially be different from the first linear polarization. Especially, in some embodiments the first linear polarization may be p-polarization and the second linear polarization may be s-polarization. In other embodiments, the first polarization may be s-polarization and the second polarization may be p-polarization. Herein, the terms “p-polarization” and “s-polarization” may especially refer to the polarization of light when incident on (a light-receiving plane of) the lightreceiving element, such as e.g. the first polarization based redirecting optical element. Hence, in embodiments, the first polarization based redirecting optical element may be configured to transmit p-polarized light received by the first polarization based redirecting optical element and to reflect s-polarized light received by the first polarization based redirecting optical element. Additionally or alternatively, in embodiments, the first polarization based redirecting optical element may be configured to transmit s-polarized light received by the 2024PF80240

[0048] 13 first polarization based redirecting optical element and to reflect p-polarized light received by the first polarization based redirecting optical element. Especially, in some such embodiments, the first polarization based redirecting optical element may be configured such that a ratio of the amount of s-polarized light being transmitted relative to the amount of p- polarized light being transmitted may be <0.9, such as <0.8, like <0.6, especially <0.4. Similarly, in some such embodiments, the first polarization based redirecting optical element may be configured such that a ratio of the amount of p-polarized light being reflected relative to the amount of s-polarized light being reflected may be <0.9, such as <0.8, like <0.6, especially <0.4. Yet alternatively, in embodiments, the first polarization based redirecting optical element may be configured to partially transmit and partially reflect one or more of light comprising the first linear polarization and light comprising the second linear polarization, see also further below. Amounts of light may be based on the spectral power (of the light) (e.g. Watts).

[0049] Hence, in embodiments, in an operational mode part of the first device light may propagate in an optical path to the luminescent material arrangement. This optical path may be via one or more optical elements, and may e.g. include a multichroic based redirecting optical element, see also below. Yet, in embodiments, in an operational mode (which may be the same as just mentioned), part of the first device light may propagate in an optical path to the diffuser arrangement. This optical path may be via one or more optical elements, and may e.g. (also) include a multichroic based redirecting optical element, see also below. The latter multichroic based redirecting optical element is herein indicated as first multichroic based redirecting optical element.

[0050] Especially, the first multichroic based redirecting optical element may be applied to combine second device light propagating to the diffuser arrangement and first device light (thereby also propagating to the diffuser arrangement). Hence, second device light propagating to the diffuser arrangement may do so via the first multichroic based redirecting optical element.

[0051] Hence, the first device light and the second device light have different spectral power distributions. Especially, in embodiments they may have emission peaks at different peak wavelengths. In embodiments, peak wavelength of emission peaks of the first device light and second device light may differ at least 5 nm, such as at least 10 nm. In embodiments, peak wavelength of emission peaks of the first device light and second device light may differ at least 15 nm, such as at least 20 nm. Hence, in specific embodiments the first device light has a first peak wavelength (<p l ) selected from the wavelength range of 2024PF80240

[0052] 14

[0053] 430-490 nm, wherein the second device light has a second peak wavelength (Zp2) selected from the wavelength range of 380-780 nm, and wherein |Z,pl-kp2| > 10 nm. In this way, the first multichroic based redirecting optical element may direct the first device light received by the first multichroic based redirecting optical element and the second device light received by the first multichroic based redirecting optical element in an optical path to the diffuser arrangement. Note that whether or not the first multichroic based redirecting optical element receives first device light may depend upon whether or not the first device is operating, and when the first device is operation, whether or not the first multichroic based redirecting optical element receives first device light may depend upon the polarization of the first device light received by the first polarization based redirecting element and the settings of the first polarization based redirecting element (see also above (and below).

[0054] Hence, in embodiments the optics may (further) comprise a first multichroic based redirecting optical element configured (a) in an optical path between the first polarization based redirecting optical element and the diffuser arrangement and (b) in an optical path between the second light generating device and the diffuser arrangement; wherein the first multichroic based redirecting optical element is configured to direct (i) first device light received via the first polarization based redirecting optical element, and (ii) second device light received from the second light generating device in an optical path to the diffuser arrangement. Here below, some specific embodiments are described. General aspects in relation to the first multichroic based redirecting optical element may also apply to other multichroic based redirecting optical elements that may be applied in the current invention.

[0055] A multichroic beam splitter (such as a dichroic beam splitter) may be considered an example of (multichroic based) redirectional optics or (multichroic based) redirecting 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, 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 2024PF80240

[0056] 15 splitter. Hence, the term multichroic beam splitter may also refer to a multichroic beam combiner.

[0057] 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, 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, 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).

[0058] In embodiments, the term “multichroic beam splitter”, and similar terms may refer to a dichroic beam splitter.

[0059] The multichroic beam splitter, especially the dichroic beam splitter, may be an embodiment of a color separation element, such as described in US7070300, which is herein incorporated by reference. Especially, the color separation element may be selected from the group of a dichroic mirror, a dichroic cube, and a diffractive optical element. Optionally, the color separation element maybe provided using a hologram. Especially, the multichroic beam splitter may be a dichroic mirror or reflector.

[0060] As indicated above, the first multichroic based redirecting optical element is configured to direct (i) first device light received via the first polarization based redirecting optical element, and (ii) second device light received from the second light generating device in an optical path to the diffuser arrangement. Hence, when the second light generating device is operating, second device light may be received by the diffuser arrangement. When the first light generating device is operation, optionally first device light may be received by the diffuser arrangement. 2024PF80240

[0061] 16

[0062] Especially, in embodiments the diffuser arrangement may comprise a diffuser configured to diffuse second device light and first device light received by the diffuser into diffused device light. As can be derived from the above, a phrase like “configured to diffuse second device light and first device light received by the diffuser into diffused device light” may refer to “configured to diffuse second device light and first device light when received by the diffuser into diffused device light”, see also above.

[0063] The diffuser arrangement may comprise a reflective diffuser arrangement or a transmissive diffuser arrangement. When the diffuser arrangement comprises a reflective diffuser arrangement, the diffuser arrangement may comprise a colinear diffuser arrangement or a non-colinear diffuser arrangement. A transmissive diffuser arrangement may imply less optics or less complicated optics. A reflective diffuser arrangement may be useful for safety reasons. Embodiments will be described below. Note that both a transmissive diffuser arrangement and a non-colinear reflective diffuser arrangement may not require additional polarizing optics (PBS) to split diffused light from incoming non-diffused light, and therefore may prevent depolarization losses that may occur with colinear reflective diffuser arrangements. Further, this may thus result in lower parts count, a smaller system volume, and lower cost. Colinear reflective diffusers and transmissive diffusers may show more ideal imaging properties for the further downstream optical system than non-colinear reflective diffusers, and therefore may result in better uniformity.

[0064] In embodiments, the diffuser arrangement may comprise a (surface) diffuser. Especially, in embodiments, the diffuser may comprise an element comprising a light- diffusive material, such as e.g. a silica, ground glass, a polymeric material, a ceramic material, a metal (lie) material, a white material, and a rough-surfaced material. The diffuser may, in embodiments, be configured to diffuse first device light and / or second device light received by the diffuser into diffused (first and / or second) device light. Especially, in embodiments, the diffuser may be configured to diffuse at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first and / or second device light received by the diffuser (arrangement) into diffused device light.

[0065] In embodiments, the diffuser may especially comprise a substantially polarization maintaining diffuser, i.e., the diffuser may be configured to substantially maintain the polarization of the incident light upon diffusion (and in some embodiments reflection). Therefore, in embodiments, the diffuser may comprise a metal coated surface textured glass substrate mounted on a heat conductive material such as e.g. a metal or a 2024PF80240

[0066] 17 ceramic. In such embodiments, the heat conductive material may be configured to conduct away heat that may be generated in the diffuser due to some absorption of incident device light.

[0067] A polarization maintain diffuser may especially be desirable when the diffuser arrangement is configured as colinear arrangement. In such embodiments, device light, which may substantially not be diffused, propagating to the diffuser arrangement may propagate at least part of its optical path via a same optical path as diffused device light (i.e. device light having been diffused at the diffuser and propagating away from the diffuser.

[0068] To separate these two types of light that may have essentially the same spectral power distributions, but may only differ in extent of diffusion (i.e. beam angle), a retarder may be applied in combination with a (second) polarization based redirecting optical element.

[0069] Hence, in embodiments, the diffuser arrangement may comprise a X / 4 waveplate. As known from the art, a waveplate or retarder is an optical device that alters the polarization state of a light wave travelling through it. A halfwave plate may shift the polarization direction of 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 (and vice versa). The X / 4 waveplate may especially be configured between (relative to the propagation of light through the system) the (second) polarization based redirecting optical element and the diffuser. In embodiments, the second polarization based redirecting optical element may thus be configured to direct (first device light and / or second) device light received by the second polarization based redirecting optical element and comprising (either) the first linear polarization or the second linear polarization (optionally via optics) to the X / 4 waveplate. The X / 4 waveplate may, in embodiments, be configured to convert (first device light and / or second) device light received by the X / 4 waveplate comprising a linear polarization into (first device light and / or second) device light having a (first) circular polarization. At the diffuser, in embodiments, the (first device light and / or second) device light having the (first) circular polarization may be diffused into diffused device light having a second circular polarization. Therefore, in embodiments, the X / 4 waveplate may also be configured to convert diffused device light received by the X / 4 waveplate (via the diffuser) and having the (second) circular polarization into diffused device light comprising a linear polarization. For example, in embodiments, p- polarized (first device light and / or second) device light may be directed by the second polarization based redirecting optical element to the X / 4 waveplate. In such embodiments, the 2024PF80240

[0070] 18

[0071] X / 4 waveplate may be configured to convert the p-polarized (first device light and / or second) device light into left-handed circularly polarized (first device light and / or second) device light. Further, in such embodiments, the diffuser may be configured to diffuse the left-handed circularly polarized (first device light and / or second) device light received by the diffuser into right-handed circularly polarized diffused device light. The X / 4 waveplate may then, in embodiments, be configured to convert the right-handed circularly polarized diffused device light received by the X / 4 waveplate (back) to linearly polarized light, especially to s-polarized diffused device light. However, in embodiments, different polarizations and conversions from the example described here may be possible too, such as e.g. starting from s-polarized (first device light and / or second) device light. Hence, in embodiments, the luminescent material and the diffuser may both be configured in the reflective mode; wherein the diffuser may comprise a polarization maintaining diffuser, and wherein the diffuser arrangement may further comprise a X / 4 waveplate configured between the second polarization based redirecting optical element and the diffuser, wherein the second polarization based redirecting optical element may be configured to direct (first device light and / or second) device light received by the second polarization based redirecting optical element and comprising the first linear polarization or the second linear polarization (optionally via optics) to the X / 4 waveplate, wherein the X / 4 waveplate may be configured to (i) convert (first device light and / or second) device light received by the X / 4 waveplate and comprising a linear polarization into (first device light and / or second) device light having a (first) circular polarization, and (ii) convert diffused device light received by the X / 4 waveplate (via the diffuser) and comprising a (second) circular polarization into diffused device light comprising a linear polarization.

[0072] Further, in embodiments wherein a colinear (reflective) diffuser arrangement is applied, the optics may thus (further) comprise a second polarization based redirecting optical element. The second polarization based redirecting optical element may be configured to direct device light comprising a first linear polarization in an optical path to the diffuser arrangement, and direct (returning) diffused device comprising a second linear polarization (complementary to the first linear polarization) in an optical path to the light exit.

[0073] Hence, in embodiments the diffuser arrangement may be configured as colinear arrangement, wherein incoming second device light, received by the diffuser arrangement, and incoming first device light (and optionally device light of other light generating devices, see below), received by the diffuser arrangement, may propagate over at least part of its optical path colinear with an optical path of the diffused device light 2024PF80240

[0074] 19 propagating from the diffuser arrangement to the light exit. Further, in (such) embodiments the diffuser may comprise a polarization maintaining diffuser. Especially, in (such) embodiments the diffuser arrangement may further comprise a X / 4 waveplate configured between the second polarization based redirecting optical element and the diffuser, wherein the second polarization based redirecting optical element may be configured to direct second device light, received by the second polarization based redirecting optical element, and first device light (and optionally device light of other light generating devices, see below ), received by the second polarization based redirecting optical element, to the X / 4 waveplate, wherein the X / 4 waveplate may be configured to convert linear polarized light received by the X / 4 waveplate into elliptical polarized light and to convert elliptical polarized light received by the X / 4 waveplate into linear polarized light. As indicated above, in embodiments the optics may thus (further) comprise a second polarization based redirecting optical element configured (a) in an optical path between the first multichroic based redirecting optical element and the diffuser arrangement, and (b) in an optical path between the diffuser arrangement and the second multichroic based redirecting optical element. Especially, in embodiments the second polarization based redirecting optical element may be configured to (i) direct (linearly polarized) second device light, received by the second polarization based redirecting optical element (via the first multichroic based redirecting optical element), and first device light, received by the second polarization based redirecting optical element (via the first multichroic based redirecting optical element), to the diffuser arrangement, and (ii) direct (linearly polarized) diffused device light received from the diffuser arrangement in an optical path to the second multichroic based redirecting optical element. Further, in embodiments the light generating system may be configured such that the second device light received by the second polarization based redirecting optical element comprises linear polarized light.

[0075] As described above, incoming light, comprising second device light and optional first device light and / or third device light, on the diffuser, has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser, and outgoing diffused device light has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser. The optical axes (Oi,Oo) have a mutual angle (P) unequal to 0°. The mutual angle (P) may in examples be larger than 10°, such as larger than 30°, especially larger than 60°, such as selected from a range of 60°-180°.

[0076] A mutual angle (P) unequal to 0° is to be interpreted such that the outgoing diffused light (downstream of the diffuser), taking the direction of propagation into account, 2024PF80240

[0077] 20 does not continue to propagate in the same direction as the incoming light (upstream of the diffuser). Hence in other words, the diffuser arrangement is not configured in the transmissive mode.

[0078] In the colinear (reflective) configuration of the diffuser arrangement, incoming light, comprising second device light and optional first device light, on the diffuser, may have an optical axis (Oi) having a first angle (ai) with a normal to the diffuser essentially equal to 0°, and the outgoing diffused device light may have an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser essentially equal to 0° (or 180°), wherein the optical axes (Oi,Oo) may have a mutual angle (P) of essentially equal to 0° (or 180°). When taking the direction of propagation into account, the second angle (ao) relative to the normal to the diffuser may be considered essentially equal to 180° and the mutual angle (P) may also be considered essentially equal to 180°, as the directions may be anti -parallel.

[0079] As indicated above, instead of a colinear (reflective) diffuser arrangement, in embodiments a non-colinear (reflective) diffuser arrangement may be applied. 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 nonzero angle with the normal. In such embodiments, maintenance of (linear) polarization may not be necessary (as is especially the case in the colinear configuration). Hence, in embodiments the diffuser arrangement may be configured as non-colinear arrangement. Especially, in (such) embodiments the light generating system may be configured such that incoming light, comprising second device light and optional first 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 mutual angles (P) may also be possible.

[0080] Yet, in alternative embodiments the diffuser arrangement may be configured in the transmissive mode. In such instance, the optical axes are essentially in each other’s extension, and could also be considered colinear, but then the directions of the propagation are the same upstream of the diffuser and downstream of the diffuser. Hence, in embodiments, in the transmissive configuration of the diffuser arrangement, incoming light, comprising second device light and optional first device light, on the diffuser, may have an optical axis (Oi) having a first angle (ai) with a normal to the diffuser essentially equal to 0°, 2024PF80240

[0081] 21 and the outgoing diffused device light may have an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser essentially equal to 0°, wherein the optical axes (Oi,Oo) may have a mutual angle (P) of essentially equal to 0°.

[0082] Note that whether or not the diffuser arrangement may receive second device light, may depend upon whether the second light generating device is operating. Whether or not the diffuser arrangement may receive first device light, may depend on whether the first light generating device is operating. If so, it may depend upon the polarization of the first device light received by the first polarization based redirecting element, as well first ((controllable) settings) of the polarization based redirecting element as such, whether at least part of the first device light is also directed in an optical path to the diffuser arrangement. Further, as indicated below, in embodiments one or more of a third light generating device, a fourth light generating device, and a fifth light generating device may be comprised by the system. Light of one or more of such devices, may be received by the diffuser arrangement, in dependence of the arrangement of such light generating device and the (controllable) settings of the system; see further also below.

[0083] As indicated above, the system may further comprise a luminescent material arrangement. In embodiments, the luminescent material arrangement comprises a luminescent material configured to convert at least part of first device light received by the luminescent material into luminescent material light.

[0084] Further, as indicated below, in embodiments one or more of a third light generating device, a fourth light generating device (and a fifth light generating device device) may be comprised by the system. Light of one or more of such devices, may be received by the luminescent material arrangement, in dependence of the arrangement of such light generating device and the (controllable) settings of the system; see further also below.

[0085] The luminescent material is configured to convert at least part of first radiation (selected from one or more of UV radiation and visible radiation), into luminescent material light. Especially, in embodiments the luminescent material may be configured to convert at least part of blue light (as radiation) into luminescent material light. Especially when blue light is partly converted, the blue light may be used as source of blue light (for the device light) and as excitation light that can be converted by the luminescent material. The first radiation may especially be provided by a (solid state) light source. Hence, in embodiments, the luminescent material may be configured to convert at least part of first device light received by the luminescent material (arrangement) into luminescent material light. As described above, in embodiments, the (part of) first device light that may be received by the 2024PF80240

[0086] 22 luminescent material may depend on the polarization (as controlled by the polarization control system) of the first device light reaching the first polarization based redirecting optical element. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light received by the luminescent material (arrangement) into luminescent material light. Additionally or alternatively, in embodiments, the luminescent material may be configured to convert at least part of second device light received by the luminescent material into luminescent material light. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the second device light received by the luminescent material (arrangement) into luminescent material light.

[0087] When different luminescent materials are applied, one or more luminescent materials may be configured to convert incident light into one or more of green and yellow luminescent material light, and one or more other luminescent materials may be configured to convert incident light into one or more of orange and red luminescent material light.

[0088] The term “luminescent material” especially refers to a material that can convert first radiati on, (especially one or more of UV radiation and blue radiation,) into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. Further, instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in the so-called downconversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in the so-called up-conversion.

[0089] In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation of a smaller wavelength is converted into radiation with a larger 2024PF80240

[0090] 23 wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation of a larger wavelength is converted into radiation with a smaller wavelength ( x> m).

[0091] In embodiments, the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and / or fluorescence.

[0092] The term “luminescent material” may also refer to a plurality of different luminescent materials. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. The term “luminescent material” herein may also refer to a material comprising a luminescent material, such as a light transmissive host comprising the luminescent material. Examples of possible luminescent materials are indicated further below.

[0093] In embodiments, luminescent materials are selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium.

[0094] Especially, the luminescent material is configured to convert at least part of the light source light into luminescent material light, wherein the luminescent material may comprise a (garnet) luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc. Hence, the luminescent material light may e.g. be green light or yellow light (or in specific embodiments even orange (dependent upon the composition of the garnet and cerium concentration)). However, other embodiments are also possible, see below. In embodiments, 0.05-10% of the A elements comprise Ce, even more especially 0.05-5%, such as 0.1-5%. Especially, embodiments, 0.1-3% of the A elements comprise Ce, such as up to 2%, like selected from the range of 0.1-1.5%, such as at least above 0.5%.

[0095] Especially, a luminescent material comprises conversion material or is a conversion material. A luminescent material converts light from a light source, such as the light source light, into secondary light (here the luminescent material light). The luminescent material may comprise an organic group that converts the light, or a molecule that converts 2024PF80240

[0096] 24 the light, or an inorganic group that converts the light, etc. Such groups (or molecule) may be indicated as converter element. The garnet type material as indicated above, comprises cerium (Ce) as converter element. Cerium comprising garnets are well known in the art.

[0097] Hence, in specific embodiments the luminescent material comprises a (first) luminescent material of the type AsBsOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc, and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi-xLux)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi-xLux)3A150i2:Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0098] In embodiments, the luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-0 may be replaced by Si-N.

[0099] In specific embodiments the luminescent material comprises (YXI-X2-X3A’X2CeX3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, 2024PF80240

[0100] 25 wherein yl+y2=l, wherein 0<y2<0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially xl>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions.

[0101] In specific embodiments at maximum 10% of B-0 may be replaced by Si-N. Here, B in B-0 refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in specific embodiments B-0 may refer to Al-O. As indicated above, in specific embodiments x3 may be selected from the range of 0.001-0.04. Especially, such luminescent materials may have a suitable spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (optionally in combination with (the) light of other sources of light as described herein). Hence, in specific embodiments A may be selected from the group consisting of Lu and Gd. Alternatively or additionally, B may comprise Ga. Hence, in embodiments the luminescent material comprises (YXI-X2- x3(Lu,Gd)x2Cex3)3(Alyi-y2Gay2)5Oi2, wherein Lu and / or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3<0.1, and wherein 0<y2<0.1. Further, in specific embodiments, at maximum 1% of B-0 may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yxi-xsCexs^ALOn, wherein xl+x3=l, and wherein 0<x3<0.2, such as 0.001-0.1.

[0102] In specific embodiments, the light generating device may only include luminescent materials selected from the type of cerium comprising garnets. In even further specific embodiments, the light generating device includes a single type of luminescent materials, such as (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Hence, in specific embodiments the light generating device comprises luminescent material, wherein at least 85 weight%, even more especially at least about 90 wt.%, such as yet even more especially at least about 95 weight % of the luminescent material comprises (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Here, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2. Especially, x3 is selected from the range of 0.001-0.1. Note that in embodiments x2=0. Alternatively or additionally, in embodiments y2=0.

[0103] In specific embodiments, A may especially comprise at least Y, and B may especially comprise at least Al. 2024PF80240

[0104] 26

[0105] Alternatively or additionally, the luminescent material may comprise a luminescent material of the type AsSieNiuCe3, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.

[0106] In specific embodiments, the luminescent material may comprise at least two different luminescent materials configured to provide luminescent material light having different spectral power distributions. As can be derived from the above, the term “different luminescent materials” may refer to luminescent materials that are different, or to two compositions, each including at least one luminescent material in common, but wherein the compositions differ. For instance, a primary luminescent material comprising luminescent materials A and B, and a secondary luminescent material comprising only A or only B, or comprising both A and B, but in a different weight ratio. Such primary luminescent material and secondary luminescent material may have different spectral power distributions of their respective luminescent material light.

[0107] The garnet type luminescent material may also be described with an alternative formula AsB^C’^On. Here, A may comprise one or more of (i) rare earth ions, such as one or more selected from Y3+, Lu3+, Gd3+, Tb3+, La3+, and (ii) divalent cations, such as Ca2+. Here, B may comprise one or more of (i) trivalent cations, such as one or more of Al3+, Ga3+, Sc3+, Sb3+, and In3+, and (ii) divalent cations, such as one or more of Mg2+and Mn2+. Here, C may comprise one or more of (i) trivalent cations, such as one or more of Ga3+and Al3+, (ii) divalent cations, such as Mn2+, and (iii) tetravalent cations, such as one or more of Si4+and Ge4+. With such ions, the garnet crystal structure can be maintained. Other substitutions than mentioned may also be possible.

[0108] In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+and / or LSisNs Eu2and / or MAlSiNs Eu2and / or Ca2AlSi3O2Ns:Eu2+, etc., wherein M comprises one or more of Ba, Sr and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace 2024PF80240

[0109] 27 divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba. The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NfcSis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and / or Ba. In a further specific embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSisNsHu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca). Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art. Hence, such nitride luminescent materials may also be or comprise converter elements, here especially Eu2+.

[0110] Especially, the luminescent material may be an inorganic luminescent material, such as one or more of the above-described trivalent cerium or divalent europium comprising oxides, oxynitrides, or nitrides.

[0111] In embodiments, a red luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba. 2024PF80240

[0112] 28

[0113] The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).

[0114] Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as NESis Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and / or Ba. In a further specific embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSisNsHu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca).

[0115] Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSi Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).

[0116] Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.

[0117] Blue luminescent materials may comprise YSO (Y2SiOs:Ce3+), or similar compounds, or BAM (BaMgAlioOi?:Eu2+), or similar compounds.

[0118] The term “luminescent material” herein especially relates to inorganic luminescent materials.

[0119] Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc.

[0120] Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used. Quantum dots show very narrow emission band and thus they show 2024PF80240

[0121] 29 saturated colors. Furthermore the emission color can easily be tuned by adapting the size of the quantum dots. Any type of quantum dot known in the art may be used in the present invention. However, it may be preferred for reasons of environmental safety and concern to use cadmium-free quantum dots or at least quantum dots having a very low cadmium content.

[0122] Instead of quantum dots or in addition to quantum dots, also other quantum confinement structures may be used. The term “quantum confinement structures” should, in the context of the present application, be understood as e.g. quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nano-wires, etcetera.

[0123] Organic phosphors can be used as well. Examples of suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, for example compounds sold under the name Lumogen® by BASF. Examples of suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170.

[0124] Different luminescent materials may have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials may especially have different color points (or dominant wavelengths).

[0125] As indicated above, other luminescent materials may also be possible. Hence, in specific embodiments the luminescent material is selected from the group of divalent europium containing nitrides, divalent europium containing oxynitrides, divalent europium containing silicates, cerium comprising garnets, and quantum structures. Quantum structures may e.g. comprise quantum dots or quantum rods (or other quantum type particles) (see above). Quantum structures may also comprise quantum wells. Quantum structures may also comprise photonic crystals.

[0126] The luminescent material may be comprised by a luminescent body. The luminescent body may be a layer, like a self-supporting layer. The luminescent body may also be a coating. The luminescent body may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode). Especially, the luminescent body may essentially be self-supporting. In embodiments, the luminescent material may be provided as luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. Such body may be indicated as “converter body” or “luminescent body”. In embodiments, the luminescent body may be a luminescent single crystal or a luminescent ceramic body. For instance, in embodiments a cerium comprising garnet luminescent material may be provided as a luminescent single crystal or as 2024PF80240

[0127] 30 a luminescent ceramic body. In other embodiments, the luminescent body may comprise a light transmissive body, wherein the luminescent material is embedded. For instance, the luminescent body may comprise a glass body, with luminescent material embedded therein. Or, the glass as such may be luminescent. In other embodiments, the luminescent body may comprise a polymeric body, with luminescent material embedded therein.

[0128] In specific embodiments, the luminescent body comprises a ceramic body comprising the luminescent material. Ceramic bodies are known in the art. Alternatively, the luminescent body comprises single crystal. In yet further specific embodiments, different types of luminescent bodies may be applied. Hence, the body may especially be selected from single crystalline bodies and ceramic bodies. The latter may be more easily made than the former, while they nevertheless may have good optical and / or thermal properties. Hence, in embodiments the body may be a ceramic body. However, in specific embodiments also a combination of single crystalline bodies and ceramic bodies may be applied. Especially, the luminescent body comprises a ceramic luminescent body. Hence, in specific embodiments the luminescent body is defined by a ceramic luminescent material. Therefore, in specific embodiments the luminescent material is a luminescent material that can be provided a ceramic luminescent body. Hence, the luminescent body may comprise a ceramic luminescent body.

[0129] Hence, in embodiments, the luminescent material arrangement may especially comprise a luminescent body comprising a luminescent material. Further, in embodiments, the (luminescent body comprising the) luminescent material may be configured in thermal contact with a thermally conductive material. Especially, in embodiments where the luminescent material is configured in the reflective mode, such thermal contact may be beneficial as the luminescent material may give rise to significant thermal dissipation. Similarly, in some embodiments, the diffuser may be configured in thermal contact with a thermally conductive material. An element may be considered in “thermal contact” with another element if it can exchange energy through the process of heat. Hence, the elements may be thermally coupled. In embodiments, thermal contact can be achieved by physical contact. In embodiments, thermal contact may be achieved via a thermally conductive material, such as a thermally conductive glue (or thermally conductive adhesive). Thermal contact may also be achieved between two elements when the two elements are arranged relative to each other at a distance of equal to or less than about 10 pm, though larger distances, such as up to 100 pm may be possible. The shorter the distance, the better the thermal contact. Especially, the distance is 10 pm or less, such as 5 pm or less, such as 1 pm 2024PF80240

[0130] 31 or less. The distance may be the distanced between two respective surfaces of the respective elements. The distance may be an average distance. For instance, the two elements may be in physical contact at one or more, such as a plurality of positions, but at one or more, especially a plurality of other positions, the elements are not in physical contact. For instance, this may be the case when one or both elements have a rough surface. When two elements are in thermal contact, they may be in physical contact or may be configured at a short distance of each other, like at maximum 10 pm, such as at maximum 1 mm. When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum. When an intermediate material is available, the larger the distance, the higher the thermal conductivity may be useful for thermal contact between the two elements. However, the smaller the distance, the lower the thermal conductivity of the intermediate material may be (of course, higher thermal conductive materials may also be used).

[0131] A thermally conductive material may especially have a thermal conductivity of at least about 20 W / (m*K), like at least about 30 W / (m*K), such as at least about 100 W / (m*K), like especially at least about 200 W / (m*K). In yet further specific embodiments, a thermally conductive material may especially have a thermal conductivity of at least about 10 W / (m*K). In embodiments, the thermally conductive material may comprise one or more of copper, aluminum, silver, gold, silicon carbide, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, a silicon carbide composite, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, diamond, and graphite. Alternatively, or additionally, the thermally conductive material may comprise or consist of aluminum oxide. In embodiments, the thermally conductive material may be comprised by and / or configured in thermal contact with one or more of a heatsink, a heat spreader, and a two-phase cooling device.

[0132] Having generated diffused device light and luminescent material light, they may be combined, such that via a mutual optical path, the diffused device light and luminescent material light may escape from the light exit. As the luminescent material light may essentially be unpolarized, it may not easily be combined with polarized diffused device light. Further, not in all embodiments herein the diffused device light is polarized light. Hence, diffused device light and luminescent material light may be combined by a multichroic based redirecting optical element, herein indicated as second multichroic based redirecting optical element. Therefore, the spectral power distributions of the diffused device 2024PF80240

[0133] 32 light and luminescent material light may especially be different. Hence, in embodiments the optics may (further) comprise a second multichroic based redirecting optical element configured (a) in an optical path between the first polarization based redirecting optical element and the luminescent material arrangement, (b) in an optical path between the luminescent material arrangement and the light exit, and (c) in an optical path between the diffuser arrangement and the light exit. Especially, in embodiments the second multichroic based redirecting optical element may be configured to direct (i) luminescent material light, received by the second multichroic based redirecting optical element, and (ii) diffused device light, received by the second multichroic based redirecting optical element, in an (mutual) optical path to the light exit.

[0134] Embodiments of multichroic beam splitters (such as a dichroic beam splitters) are discussed above. In relation to the second multichroic based redirecting optical element, in embodiments the second multichroic based redirecting optical element may be reflective (and not transmissive) for luminescent material light and transmissive (and not reflective) for diffused (device) light, and in other embodiments the second multichroic based redirecting optical element may be transmissive (and not reflective) for luminescent material light and reflective (and not transmissive) for diffused (device) light.

[0135] Note that in embodiments in the optical path between the first polarization based redirecting optical element and the luminescent material arrangement there may be no further multichroic based redirecting optical elements and / or polarization based redirecting optical elements, though other embodiments are herein not excluded. Note that also in embodiments in the optical path between the luminescent material arrangement and the light exit, there may be no further multichroic based redirecting optical elements and / or polarization based redirecting optical elements. However, note that in embodiments in the optical path between the diffuser arrangement and the light exit, there may be a second polarization based redirecting optical element configured downstream of the diffuser arrangement and upstream of the second multichroic based redirecting optical element, especially when the diffuser arrangement is a colinear (reflective) diffuser arrangement.

[0136] As indicated above, the light generating system may further comprise a light exit. Herein, the light exit may refer to a position where system light escapes from the light generating system. This may, in embodiments, be a light transmissive window or an opening (in the system). The light transmissive window may in embodiments be provided by an optical component. The light exit may (thus) comprise an end window or an (other) optical element, like a lens, or an opening, from which the system light may escape to the external of 2024PF80240

[0137] 33 the system. The system may comprise a housing, comprising such light exit. The housing may at least partly enclose one or more light generating devices and one or more (other) optical elements. Hence, the light generating system may be configured to provide, via the light exit, system light.

[0138] The system light may in embodiments have a fixed spectral power distribution. This does not exclude the possibility that during production, or directly after production, or when installing, this spectral power distribution is set (e.g. then setting a figured (rotational) configuration of the optics and light generating devices relative to each other (see also below). Hence, the system may in embodiments have a single operational mode.

[0139] In other embodiments, however, the spectral power distribution of the system light may be controllable. In such embodiments, the system may have a plurality of operational modes. Especially, in such embodiments the system may (further) comprise a control system, wherein the control system may be configured to control the system light.

[0140] The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and / or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

[0141] The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is 2024PF80240

[0142] 34 thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0143] Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

[0144] The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “operational mode may also be indicated as “controlling mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and / or after executing the mode one or more other modes may be executed.

[0145] However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

[0146] Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and / or a predetermined time scheme.

[0147] Especially, in embodiments the system light may in a first operational mode of the light generating system comprise at least part of the luminescent material light and at least part of the diffused device light, and have a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65. Hence, in 2024PF80240

[0148] 35 embodiments the system light may (in an operational mode of the light generating system) be white light.

[0149] The term “white light”, and similar terms, herein, is known to the person skilled in the art. It may especially relate to light having a correlated color temperature (CCT) between about 1800 K and 20000 K, such as between 2000 and 20000 K, especially 2700- 20000 K, for general lighting especially in the range of about 2000-7000 K, such as in the range of 2700 K and 6500 K. In embodiments, e.g. for backlighting purposes, or for other purposes, the correlated color temperature (CCT) may especially be in the range of about 7000 K and 20000 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL.

[0150] In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, like at least 8000 K. Yet further, in embodiments the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 70. In embodiments, the CRI may be at least 75, such as at least about 80, or even at least 85.

[0151] The spectral power distribution may be controlled by controlling the light generating devices, i.e. their radiant fluxes. For instance, when the radiant flux of the second device light is increased, its relative contribution to the system light may be increased. When the radiant flux of the first device light is increased, the contribution to the system light of the luminescent material light may be increased. However, as there may be a fixed ratio between the radiant flux of the first device light propagating to the diffuser arrangement and the luminescent material arrangement, also the contribution to the system light of diffused first device light may be increased. Further, as indicated below, in embodiments one or more of a third light generating device and a fourth light generating device may be comprised by the system. Light of one or more of such devices, may be received by the luminescent material arrangement. Also for the third device and / or the fourth device light may apply that there may be a fixed ratio between the radiant flux of their respective device light propagating to the diffuser arrangement and the luminescent material arrangement, as they, when present, are configured upstream of the first polarization based redirection optical element. Further, as indicated below, in embodiments a fifth light generating device may be comprised by the system. When the radiant flux of the fifth device light is increased, its relative contribution to 2024PF80240

[0152] 36 the system light may be increased, as essentially all of its device light, like the second device light, may be introduced in the channel to the diffuser arrangement. As indicated above, the control of the radiant flux of the first device light, optional second device light, and optional third device light may not have impact on the ratio of their respective device light propagating to the diffuser arrangement and the luminescent material arrangement.

[0153] However, a ratio of the first device light (and the optional third device light and the optional fourth device light) propagating to the diffuser arrangement and the luminescent material arrangement may in embodiments be controlled by controlling the polarization of the device light that is received at the first polarization based redirection optical element. Control of polarization may in embodiments be achieved via a birefringent rotator and / or in other embodiments be achieved by rotation the light generating device about its optical axis. One or both of these options may be executed with a polarization control system.

[0154] Hence, to this end, the light generating system may in embodiments further comprise a polarization control system. Especially, the polarization control system may be configured to control a polarization of the first device light reaching the first polarization based redirecting optical element, thereby controlling a power distribution of the first device light over the optical paths to the luminescent material arrangement and the diffuser arrangement. Further, in embodiments the polarization control system may comprise one or more of: (a) a birefringent rotator configured downstream of the first light generating device and upstream of the first polarization based redirecting optical element, wherein the polarization control system may be configured to control rotation of the birefringent rotator; and wherein the birefringent rotator comprises a X / 2 waveplate; and (b) an actuator configured to rotate the first light generating device, wherein the polarization control system is configured to control the actuator. Especially, the control system may be configured to control a spectral power distribution of the system light by controlling one or more of (i) the polarization control system and (ii) one or more of the light generating devices.

[0155] Herein, the phrase “controlling one or more of the light generating devices”, and similar phrases, may especially refer to controlling the output power of the light generating device(s) (e.g. by controlling its drive current (including in embodiments pulse width modulation)).

[0156] Here above, the polarization control in relation to the first device light is described. However, it is herein not excluded that, especially in addition to the polarization 2024PF80240

[0157] 37 control in relation to the first device light, also in (a) similar way(s) the polarization may be controlled of the optional third device light and / or of the optional fourth device light.

[0158] The polarization control system in combination with the polarization based redirection optical element allows control of the relative contributions of the first device light over the optical paths to the luminescent material arrangement and the diffuser arrangement. Especially, in embodiments the first polarization based redirecting optical element may comprise a polarizing beam splitter or a partial polarizing beam splitter.

[0159] In embodiments, for the first polarization based redirecting optical element one of the following may apply: (a) the first polarization based redirecting optical element may be fully reflective for s-polarized blue device light and fully transmissive for p-polarized blue device light; or (b) the first polarization based redirecting optical element may be fully transmissive for p-polarized blue device light and partly transmissive (and partly reflective) for s-polarized blue device light; or (c) the first polarization based redirecting optical element; may be fully reflective for s-polarized blue device light and partly transmissive (and partly reflective) for p-polarized blue device light; or (d) the first polarization based redirecting optical element may be partly reflective and partly transmissive for both s- polarized and p-polarized blue device light; wherein the polarization may be referenced to a splitting plane of the polarizing beam splitter or the partial polarizing beam splitter, wherein the splitting plane may be a plane at which the polarization based beam splitting (i.e., transmission and reflection) takes place.

[0160] As indicated above, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarization based redirecting optical element. Especially, in embodiments, the polarization control system may be configured such that xl% of first device light comprising the first linear polarization and yl% of first device light comprising the second linear polarization may be provided to the first polarization based redirecting optical element. Herein, in embodiments, xl and yl may be individually selected from the range of 0-100%, such as from the range of 10-90%, like from the range of 20-80%. In some embodiments, the polarization control system may be configured such that only first device light comprising the first linear polarization may be provided to the first polarization based redirecting optical element, i.e., xl=100% and yl=0%. In other embodiments, the polarization control system may be configured such that only first device light comprising the second linear polarization may be provided to the first polarization based redirecting optical element, i.e., y 1=100% and xl=0%. In yet other embodiments, the polarization control system may be configured such 2024PF80240

[0161] 38 that a combination of first device light comprising the first linear polarization and first device light comprising the second linear polarization may be provided to the first polarization based redirecting optical element, i.e., xl^0%, yl^0%, and xl+yl=100%. For example, in embodiments, the polarization control system may be configured such that x=70% of first device light comprising the first linear polarization and y=30% of first device light comprising the second linear polarization may be provided to the first polarization based redirecting optical element, or vice versa (i.e., xl=30% and yl=70%).

[0162] Hence, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarization based redirecting optical element. Especially, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarization based redirecting optical element, such that (selected from the range of) 50-98% of the first device light received by the first polarization based redirecting optical element may be directed to the luminescent material arrangement. More especially, in embodiments, at least 50%, such as at least 60%, especially at least 70%, like at least 80% of the first device light received by the first polarization based redirecting optical element may be directed to the luminescent material arrangement. Further, in embodiments, at most 99%, such as at most 98%, like at most 95%, especially at most 90%, more especially at most 80% of the first device light received by the first polarization based redirecting optical element may be directed to the luminescent material arrangement. Hence, in embodiments, the polarization control system may be configured to control a polarization of the first device light reaching the first polarization based redirecting optical element, such that (selected from the range of) 50-98% of the first device light received by the first polarization based redirecting optical element may be directed to the luminescent material arrangement.

[0163] Hence, in embodiments, in a first operational mode of the light generating system the first polarization based redirecting optical element may be configured to direct part of (or even essentially all of) the first device light to the luminescent material arrangement. Additionally or alternatively, in embodiments, in a first operational mode of the light generating system the first polarization based redirecting optical element may be configured to direct part of (or even essentially all of) the first device light to the diffuser arrangement. Note that herein, in embodiments, the light generating system may be operated in a plurality of (different) operational modes, such as the first operational mode indicated above. Furthermore, in embodiments, the term “first operational mode” may herein also refer to a plurality of (different) first operational modes. Especially, in embodiments, in a first 2024PF80240

[0164] 39 operational mode of the light generating system the first polarization based redirecting optical element may be configured to direct at most 50%, such as at most 40%, like at most 30%, especially at most 20%, more especially at most 10%, including 0% of the first device light to the diffuser arrangement. However, in alternative embodiments, in a first operational mode of the light generating system the first polarization based redirecting optical element may be configured to direct at least 50%, such as at least 60%, like at least 70%, especially at least 80%, more especially at least 90%, including 100% of the first device light to the diffuser arrangement. The first polarization based redirecting optical element may thus, in embodiments, be configured to (re-)direct the (first) device light received by the first polarization based redirecting optical element in dependence of its polarization. Hence, in embodiments, in a first operational mode of the light generating system in dependence of the polarization at least part of the first device light received by the first polarization based redirecting optical element may be directed towards the luminescent material arrangement and / or at least (another) part of the first device light received by the first polarization based redirecting optical element may be directed towards the diffuser arrangement.

[0165] Therefore, in embodiments the light generating system may be configured to generate in an operational mode of the light generating system white system light comprising luminescent material light and diffused device light, wherein the diffused device light may comprise contributions from (both) the first device light and the second device light.

[0166] As indicated above, in embodiments a birefringent rotator (wherein in specific embodiments the birefringent rotator comprises a X / 2 waveplate) may be used to control polarization of the first device light. Alternatively or additionally, a rotational position of the first light generating device may be used to control polarization of the first device light. For controlling, the polarization control system (controlled by the control system) may be applied. However, it may also be possible that a birefringent rotator is applied with a fixed setting. Likewise, even when the rotation of the first light generating device may not be controllable, it may have a fixed rotational position. Hence, the birefringent rotator and / or the first light generating device may be fixated in a calibrated position during assembly without having a further need for controlling its orientation (during operation of the system).

[0167] As indicated above, whereas in embodiments, the second device light may essentially exist of light having spectral intensity in the 430-490 nm wavelength range, such at least 80%, like at least 90% of the spectral power in this wavelength range, it is herein not excluded that in other embodiments the second device light has a peak wavelength in another wavelength range, such as in the orange wavelength range or red wavelength range, or that in 2024PF80240

[0168] 40 more specific embodiments, the second device light may consist of light having multiple peaks, such as one in the blue wavelength range, and one in the red wavelength range. Hence, in other specific embodiments, the second device light may comprise one or more of blue light and red light (see also below).

[0169] Hence, in specific embodiments the second device light has a second peak wavelength (Zp2) selected from the wavelength range of 590-780 nm, such as especially selected from the wavelength range of 590-750 nm, more especially selected from the wavelength range of 590-660 nm. In this way, via the diffuser channel diffused second device light in the orange-red wavelength range may end up in the system light.

[0170] In alternative embodiments, however, the second light generating device may be configured to generate primary second device light (121a) having spectral power in a first wavelength range of 430-490 nm and secondary second device light (121b) having spectral power in a second wavelength range of 590-780 nm (such as especially selected from the wavelength range of 590-750 nm, more especially selected from the wavelength range of 590-660 nm). For instance, the second light generating device may comprise one or more laser banks comprise blue lasers and orange laser or blue lasers and red lasers, like a single laser bank comprising blue lasers and red lasers. In this way, via the diffuser channel diffused second device light in the blue and orange-red wavelength range may end up in the system light. Hence, in embodiments in an operational mode of the light generating system, the diffused device light may comprise contributions of the primary second device light (121a) and the secondary second device light (121b).

[0171] The phrase “in the orange-red wavelength range”, and similar phrases, may indicate spectral power at one or more wavelengths in the orange wavelength range and / or spectral power at one or more wavelengths in the red wavelength range. The orange-red wavelength range is defined as the 590-750 nm wavelength range. Note that the luminescent material providing luminescent material light having spectral power in the orange-red wavelength range may in embodiments only have spectral power in this 590-750 nm wavelength range (within the 380-780 nm wavelength range), but may in other embodiments also have spectral power within the 380-780 nm wavelength range at other wavelengths than within the 590-750 nm wavelength range.

[0172] As indicated above, the (first) light generating device may comprise one or more of laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. Further, the (first) light generating device may (thus) also comprise one or more of a plurality of laser diodes, a plurality of superluminescent diodes, and a plurality of stacked 2024PF80240

[0173] 41 multi -junction light-emitting diodes. Hence, in embodiments the (first) light generating device may comprise a (first) laser bank. Likewise, such embodiments may apply to one or more of the second light generating device, the optional third light generating device, the optional fourth light generating device, and the optional fifth light generating device.

[0174] When adding further light generating devices to the light generating system, it may in general refer to light generating devices generating device light that have spectral power distributions different from the first device light and the second device light. When adding one or more of such additional light generating devices, dependent upon whether they are intended to (a) provide light in an optical path to the luminescent material arrangement and optionally the diffuser arrangement, or (b) provide light in an optical path to the diffuser arrangement, the spectral power distribution of such additional light generating devices may be selected. In the former embodiment, the device light of the additional light generating device should be convertible by the luminescent material into luminescent material light. In the latter embodiment, there is not such condition, though its spectral power distribution and the optics should be selected such that the diffused additional device light should be combinable with the luminescent material light in an optical path to the light exit (as the second multichroic based redirecting optical element may be involved). Herein, the third light generating device and the fourth light generating device may especially be related to the former embodiment (i.e. intended to (a) provide light in an optical path to the luminescent material arrangement and optionally the diffuser arrangement), whereas the fifth light generating device may especially be related to the latter embodiment (i.e. intended to (b) provide light in an optical path to the diffuser arrangement). Below, some embodiments are described in relation to the third light generating device, the fourth light generating device, and the fifth light generating device.

[0175] Hence, in embodiments, the light generating system may further comprise a third light generating device. General embodiments in relation to light generating devices are described elsewhere herein (see e.g. also above). For the sake of completeness, however, especially the third light generating device may be configured to generate third device light and in specific embodiments the third light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. Further, as indicated above, the third light generating device may be selected such that at least part of its third device light may be converted by the luminescent material. Hence, in specific embodiments, the third device light may have spectral power in the wavelength range of 380-490 nm, especially selected from the wavelength range of 430-490 nm. For 2024PF80240

[0176] 42 instance, though not exclusively, the third device light may have a third peak wavelength (Xp3) selected from the wavelength range of 380-490 nm, especially selected from the wavelength range of 430-490 nm. In embodiments, |Xp3- kp l |< 20 nm, such as |Xp3- kp l |< 10 nm, like in specific embodiments |Xp3- kp l |< 5 nm.

[0177] Further, in specific embodiments the light generating system may be configured such that (a) the first polarization based redirecting optical element is configured in a light-receiving relationship with the third light generating device, and (b) the third device light received by the first polarization based redirecting optical element comprises linear polarized light. Hence, especially the first polarization based redirecting optical element may be configured to direct at least part of the third device light (in dependence of its (linear) polarization) in an optical path to the luminescent material arrangement.

[0178] In at least one of the operational modes, the first device light and third device light may both primarily have the same linear polarization.

[0179] Hence, in embodiments the luminescent material may be configured to (also) convert at least part of third device light received by the luminescent material into luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light and third device light). Further, in embodiments the diffuser may be configured to diffuse (second device light and first device light and) third device light received by the diffuser into diffused device light(which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused third device light). Further, in embodiments the first multichroic based redirecting optical element may be configured to direct (also) third device light received via the first polarization based redirecting optical element in an optical path to the diffuser arrangement. Yet, further in embodiments the second multichroic based redirecting optical element may be configured to direct (i) luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light and third device light), received by the second multichroic based redirecting optical element, and (ii) diffused device light (which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused third device light), received by the second multichroic based redirecting optical element, in an (mutual optical path to the light exit. Hence, in embodiments the system light in an operational mode of the light generating system may comprise at least part of the luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light and third device light) and at least part of the diffused device light (which in 2024PF80240

[0180] 43 specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused third device light), and may have in specific embodiments a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

[0181] Hence, in embodiments (in an operational mode) the polarization of the first device light may be selected such it comprises the same ratio of s- and p-polarized light as the third device light. However, in other embodiments (in an operational mode) both the first and the third device light contribute to the luminescent conversion while at least the first light may additionally contribute to the diffused device light. For this, generally the polarizations of the first and third device light upon arrival at the first polarization based redirection optical element may not the same.

[0182] As indicated above, in embodiments the spectral power distribution of the system light may be controllable. In embodiments, the control system may be configured to control the spectral power distribution of the system light by controlling one or more of (a) a rotation of the birefringent rotator, (b) one or more of the first light generating device, the second light generating device, and the third light generating device (i.e. the respective radiant flux(es)), and (c) one or more of a rotational position of the first light generating device and the third light generating device. Herein, rotational positions of light generating devices especially refer to a rotation (of the light generating device) about the optical axis of the light emitted by the respective light generating device towards to the first polarization based redirecting optical element.

[0183] The second multichroic based redirecting optical element may be configured such that at least part of the diffused device light, received by the second multichroic based redirecting optical element, and at least part of the luminescent material light, received by the second multichroic based redirecting optical element, are directed in an optical path to the light exit. In general, the diffused device light and the luminescent material light may propagate along orthogonal paths to the second multichroic based redirecting optical element. Hence, the second multichroic based redirecting optical element should in general at least be configured (a) to transmit at least part of the luminescent material light and reflect at least part of the diffused device light, or (b) to reflect at least part of the luminescent material light and transmit at least part of the diffused device light. Hence, in embodiments the second multichroic based redirecting optical element may be transmissive for luminescent material light and reflective for diffused device light. In other embodiments, however, the second multichroic based redirecting optical element may be reflective for luminescent material light 2024PF80240

[0184] 44 and transmissive for diffused device light. When the spectral power distributions of the diffused device light and the luminescent material light are substantially different, and dependent upon the spectral power distributions, the second multichroic based redirecting optical element may comprise one of a long-wavelength-pass DBS, a short-wavelength-pass DBS, a spectral band (or multiband) reflective filter (or combination of reflective filters), or a spectral band (or multi-band) transmissive filter, etc. Further, in embodiments notch filters may be combined as they have little to negligible impact on spectral components outside of the reflection band. They also can be easily combined with longpass or shortpass filters if the reflection band is in the spectral transmission range of these filters. On the other hand, bandpass filters may not generally be combined with other filters that would be active outside of that band, as anyway the light would be reflected in all cases in those spectral ranges. Therefore, bandpass filters seem to be relevant for these engines only when the band covers most of the luminescent spectral range, or when they are used essentially as a dichroic (longpass or shortpass) filter. However, it may be possible to design dielectric coatings that provide a combination of a notch filter and a highpass or lowpass filter (such as a reflective band in the red spectral range and a high reflectance in the blue and optionally shorter wavelength range), or a dual notch filter (with a first reflection band in the blue and a second reflection band in the red spectral range).

[0185] Particularly interesting embodiments comprising both blue and red light in the diffused device light may be enabled by the second multichroic based redirecting optical element (spectral filter SBS2) that either: (a) reflects the blue device light and the red device light, while transmitting in between these red and blue device light spectral bands as well as above the red device light spectral band; this may conveniently be realized by the combination of a narrow band notch (reflection) filter for the red device light and a longpass dichroic filter that transmits the luminescent light and reflects the blue device light; the notch bandwidth may be designed in the range of 5 to 15 nm with a center wavelength in the range of 610 - 650 nm, or (b) transmits the blue device light and the red device light, while reflecting (luminescent) light in between these red and blue device light spectral bands as well as above the red device light spectral band; this may conveniently be realized by the combination of a wideband notch filter covering the spectral range between the blue and the red device light spectral bands, and a shortpass dichroic filter that reflects light with wavelengths above the red device light spectral band and transmits light with wavelengths below the upper wavelength limit of the red device light spectral band; for red lasers emitting 2024PF80240

[0186] 45 at ca 640 nm and blue lasers emitting below 470 nm, the notch band may be designed from ca 470 nm to ca 635 nm.

[0187] In embodiments, the luminescent material may be selected to provide luminescent material light having spectral power within the wavelength range of 490-590 nm. Further, in embodiments wherein the second device light may have spectral power in the 590-780 nm, the luminescent material may be selected to provide luminescent material light especially having a centroid wavelength (XLc) smaller than a peak wavelength of the second device light within the second wavelength range of 590-780 nm.

[0188] In embodiments, it may be desirable that a peak wavelength of the second device light at shorter wavelengths than the centroid wavelength (ZLc) of the luminescent material, differs at least 20 nm with the centroid wavelength (ZLc) of the luminescent material, i.e. ZLc-Ap2> 20 nm. However, in other embodiments, it may be desirable that a peak wavelength of the second device light at larger wavelengths than the centroid wavelength (ZLc) of the luminescent material, also differs at least 20 nm with the centroid wavelength (ZLc) of the luminescent material, i.e. Ap2-kLc> 20 nm. Yet, in embodiments that the second device light has a first peak wavelength (Zp2a) smaller than the centroid wavelength (ZLc) of the luminescent material, and a second peak wavelength (Zp2b) larger than the centroid wavelength (ZLc) of the luminescent material, then kLc-kp2a> 20 nm and kp2b-kLc> 20 nm may apply. Especially, one or more of the differences may be at least 25 nm, such at least 30 nm.

[0189] In embodiments, the diffuser arrangement is configured as non-colinear arrangement, and the polarization control system comprises the birefringent rotator. In other embodiments, the diffuser arrangement is configured as colinear arrangement, and the polarization control system comprises the birefringent rotator. In other embodiments, the diffuser arrangement is configured as transmissive arrangement, and the polarization control system comprises the birefringent rotator. In yet other embodiments, the diffuser arrangement is configured as non-colinear arrangement, and the polarization control system comprises an actuator to rotate one of the light generating devices (like the first light generating device). In other embodiments, the diffuser arrangement is configured as colinear arrangement, and the polarization control system comprises an actuator to rotate one of the light generating devices (like the first light generating device). In other embodiments, the diffuser arrangement is configured as transmissive arrangement, and the polarization control system comprises an actuator to rotate one of the light generating devices (like the first light generating device). 2024PF80240

[0190] 46

[0191] Hence, in embodiments, the light generating system may further comprise a fourth light generating device. General embodiments in relation to light generating devices are described elsewhere herein (see e.g. also above). For the sake of completeness, however, especially the fourth light generating device may be configured to generate fourth device light and in specific embodiments the fourth light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. Further, as indicated above, the fourth light generating device may be selected such that at least part of its fourth device light may be converted by the luminescent material. Hence, in specific embodiments, the fourth device light may have spectral power in the wavelength range of 380-490 nm, especially selected from the wavelength range of 430-490 nm. For instance, though not exclusively, the fourth device light may have a fourth peak wavelength (Xp4) selected from the wavelength range of 380-490 nm, especially selected from the wavelength range of 430-490 nm. Especially, the fourth device light may be admixed with the first device light (or, alternatively, admixed with the third device light) via a third multi chroic based redirecting optical element. Hence, in embodiments, |Xp4-Xpl |> 5 nm, such as |Xp4- kp l |> 10 nm, like in specific embodiments |Xp4- kp l |> 15 nm, more especially |Xp4- Xpl |> 20 nm. In specific embodiments, the fourth device light may have a fourth peak wavelength (Xp4) selected from the wavelength range of (380-490 nm, more especially selected from the wavelength range of) 430-490 nm and / or the first device light may have a first peak wavelength (Xp l ) selected from the wavelength range of 430-490 nm, and wherein especially | Xp4-X.pl | > 10 nm applies. Especially, in embodiments | Xp4-Xpl | < 50 nm, such as 5 nm < | Xp4-Xpl | < 50 nm.

[0192] Hence, in embodiments the system may (further) comprise a fourth light generating device and a third multichroic based redirecting optical element.

[0193] Note that in embodiments, no third light generating device and no fourth light generating device may be comprised by the system, in other embodiments the third light generating device may be comprised by the system but no fourth light generating device may be comprised by the system, in yet other embodiments no third light generating device may be comprised by the system but the fourth light generating device may be comprised by the system, and in yet other embodiments both the third light generating device and the fourth light generating device may be comprised by the system.

[0194] Hence, in embodiments the luminescent material may be configured to (also) convert at least part of fourth device light (and optionally third device light) received by the luminescent material into luminescent material light (which in specific embodiments in an 2024PF80240

[0195] 47 operational mode may thus be generated by the first device light and fourth device light (and optionally third device light)). Further, in embodiments the diffuser may be configured to diffuse (second device light and first device light and) fourth device light (and optionally third device light) received by the diffuser into diffused device light( which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused fourth device light (and optionally third device light)). Further, in embodiments the first multichroic based redirecting optical element may be configured to direct (also) fourth device light (and optionally third device light) received via the first polarization based redirecting optical element in an optical path to the diffuser arrangement. Yet, further in embodiments the second multichroic based redirecting optical element may be configured to direct (i) luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light and fourth device light (and optionally third device light)), received by the second multichroic based redirecting optical element, and (ii) diffused device light (which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and optionally diffused fourth device light (and optionally third device light)), received by the second multichroic based redirecting optical element, in an (mutual optical path to the light exit. Hence, in embodiments the system light in an operational mode of the light generating system may comprises at least part of the luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light and fourth device light (and optionally third device light)) and at least part of the diffused device light (which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and optionally diffused fourth device light (and optionally third device light)), and may have in specific embodiments a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

[0196] As indicated above, in embodiments the spectral power distribution of the system light may be controllable. In embodiments, the control system may be configured to control the spectral power distribution of the system light by controlling one or more of (a) a rotation of the birefringent rotator and (b) one or more of the first light generating device, the second light generating device, and the fourth light generating device (and optionally third light generating device) (i.e. the respective radiant flux(es)), and (c) one or more of a rotational position of the first light generating device and the fourth light generating device (and optionally third light generating device). Herein, rotational positions of light generating 2024PF80240

[0197] 48 devices especially refer to a rotation (of the light generating device) about the optical axis of the light emitted by the respective light generating device towards to the downstream configured polarization based redirecting optical element.

[0198] Especially, in embodiments the fourth light generating device may be applied in combination with the third light generating device. In such embodiments, the first device light may be provided to the first polarization based redirection optical element, without intermediate polarization based redirection optical element and / or multichroic based redirection optical element, whereas the third device light and fourth device light may be provided to the first polarization based redirection optical element via an intermediate multichroic based redirection optical element (i.e. the third multichroic based redirecting optical element). In alternative embodiments, the third device light may be provided to the first polarization based redirection optical element, without intermediate polarization based redirection optical element and / or multichroic based redirection optical element, whereas the first device light and fourth device light may be provided to the first polarization based redirection optical element via an intermediate multichroic based redirection optical element i.e. the third multichroic based redirecting optical element).

[0199] Hence, the fourth device light (and / or the third device light) may comprise linear polarized light. Hence, in embodiments the light generating system may be configured such that (a) the first polarization based redirecting optical element is configured in a lightreceiving relationship with the fourth light generating device, and (b) the fourth device light received by the first polarization based redirecting optical element comprises linear polarized light.

[0200] Further, in specific embodiments, the light generating system may be configured such that the third multichroic based redirecting optical element is configured (i) downstream of the fourth light generating device and (ii) upstream of the first polarization based redirecting optical element. Yet, in (such) specific embodiments the third multichroic based redirecting optical element may be configured to receive fourth device light and to direct (at least part of the received) fourth device light to the first polarization based redirecting optical element. Further, in specific embodiments the third multichroic based redirecting optical element may (thus also) be configured (i) downstream of both the first light generating device and the fourth light generating device and (ii) upstream of the first polarization based redirecting optical element. Yet, in (such specific) embodiments the third multichroic based redirecting optical element may be configured to receive first device light and fourth device light and to direct (first device light and fourth device light) to the first 2024PF80240

[0201] 49 polarization based redirecting optical element. However, as indicated above, other configurations may also be possible.

[0202] Further, in embodiments in addition to controllability of the polarization of the first device light reaching the first polarization based redirection optical element, optionally the polarization of the fourth device light reaching the first polarization based redirection optical element and / or the polarization of the third device light reaching the first polarization based redirection optical element may be controlled.

[0203] In specific embodiments, the first polarization based redirecting optical element may be configured to direct (at least part of the first device light received by the first polarization based redirecting optical element and) at least part of the fourth device light received by the first polarization based redirecting optical element (and optionally at least part of the third device light from the third light generating device received by the first polarization based redirecting optical element) (in dependence of the (respective) (linear) polarization) in an optical path to the luminescent material arrangement. However, the first polarization based redirecting optical element may thus also be configured to direct one or more of (a) at least part of the first device light received by the first polarization based redirecting optical element and (b) at least part of the optional fourth device light received by the first polarization based redirecting optical element, and (c) optionally at least part of the third device light from the third light generating device received by the first polarization based redirecting optical element) (in dependence of the respective (linear) polarization) in an optical path to the diffuser arrangement.

[0204] In embodiments, wherein the light generating system comprises the third light generating device the third device light reaching the first polarization based redirecting optical element may comprise a linear polarization complementary to the fourth device light, especially when the first light generating device may be configured upstream of the third multichroic based redirecting optical element, the fourth light generating device may (also) be configured upstream of the third multichroic based redirecting optical element, and the third light generating device may not be configured upstream of the third multichroic based redirecting optical element (but upstream of the first polarization based redirecting optical element). Note that the third multichroic based redirecting optical element may be configured upstream of the first polarization based redirecting optical element.

[0205] However, in other embodiments, wherein the light generating system may (also) comprise the third light generating device, the third device light reaching the first polarization based redirecting optical element may comprise a linear polarization 2024PF80240

[0206] 50 substantially the same as the fourth device light, especially when the first light generating device may not be configured upstream of the third multichroic based redirecting optical element (but upstream of the first polarization based redirecting optical element), and the fourth light generating device and the third light generating device may be configured upstream of the third multichroic based redirecting optical element. Again, note that the third multichroic based redirecting optical element may be configured upstream of the first polarization based redirecting optical element.

[0207] In embodiments, especially the former embodiments, the first polarization based redirecting optical element may at least partially be transmissive for the linear polarization of the third device light, at least partially reflective for the linear polarization of the fourth device light and at least partially reflective for the linear polarization of the fist device light. In embodiments, especially the latter embodiments, the first polarization based redirecting optical element may at least partially be transmissive for the linear polarization of the first device light, at least partially reflective for the linear polarization of the fourth device light, and at least partially reflective for the linear polarization of the third device light. Further, embodiments, however, may also be possible, as the two orthogonal branches upstream of the first polarization based redirecting optical element, may also be interchanged.

[0208] Above, several embodiments have been described in relation to adding light generating devices in the channel to (optionally) at least the luminescent material arrangement. In other words, the additional optional third light generating device and optional fourth light generating device, are (is) configured upstream of the first polarization based redirecting optical element.

[0209] However, alternatively or additionally, in embodiments it may also be possible to add light generating devices in the channel to the diffuser arrangement. In general, such additional light generating device(s) is (are) configured upstream from the first multichroic based redirecting optical element and not upstream of the first polarization based redirecting optical element. Especially when the diffuser arrangement is a transmissive arrangement or non-colinear arrangement, adding further light generating devices in the branch of the diffuser arrangement may be done via multichroic multiplexing and / or polarization multiplexing. However, when the diffuser arrangement is a colinear arrangement, in principle, multichroic multiplexing may be the only option.

[0210] Above, the embodiments have been described wherein the second light generating device may be configured to provide device light in two different optical regions. However, in such embodiments, the optical path of both types of second device light is 2024PF80240

[0211] 51 essentially fully colinear. Here below, some embodiments are described wherein the optical paths of device light of different spectral power distributions is not fully colinear, and multichroic multiplexing is applied to combine them in one optical path to the diffuser arrangement.

[0212] Conditions for multichroic multiplexing are (i) a difference in spectral power distribution and (ii) a multichroic based redirecting optical element that has a difference in transmission and / or a difference in reflectance for different parts of the spectral wavelength range, thereby having different impacts in terms of transmission and reflection for at least parts of the different spectral power distributions. Multichroic multiplexing may especially be applied when the respective spectral power distributions comprise single emission peaks at different wavelengths, though other embodiments are certainly also possible.

[0213] Hence, in embodiments the system may further comprises a fifth light generating device and a fourth multichroic based redirecting optical element.

[0214] Note that in embodiments, a fifth light generating device may be comprised by the system, but no third light generating device and / or no fourth light generating device. In other embodiments, a fifth light generating device may be comprised by the system, as well as a third light generating device, but no fourth light generating device. Likewise, in other embodiments, a fifth light generating device may be comprised by the system, as well as a fourth light generating device, but no third light generating device. Hence, in embodiments, the system may comprises a fifth light generating device, a third light generating device, a fourth light generating device (and of course the first light generating device and the second light generating device).

[0215] Hence, in embodiments the diffuser may be configured to diffuse (second device light and first device light and) fifth device light (and optionally one or more of fourth device light and third device light) received by the diffuser into diffused device light(which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused fifth device light (and optionally one or more of diffused fourth device light and diffused third device light). Further, in embodiments the first multichroic based redirecting optical element may be configured to direct (also) fifth device light (and optionally one or more of fourth device light and third device light received via the first polarization based redirecting optical element) in an optical path to the diffuser arrangement. Yet, further in embodiments the second multichroic based redirecting optical element may be configured to direct (i) luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light (and 2024PF80240

[0216] 52 optionally one or more of fourth device light and third device light), received by the second multichroic based redirecting optical element, and (ii) diffused device light (which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused fifth device light (and optionally one or more of diffused fourth device light and diffused third device light)), received by the second multichroic based redirecting optical element, in an (mutual) optical path to the light exit. Hence, in embodiments the system light in an operational mode of the light generating system may comprises at least part of the luminescent material light (which in specific embodiments in an operational mode may thus be generated by the first device light (and optionally one or more of fourth device light and third device light)) and at least part of the diffused device light (which in specific embodiments in an operational mode may thus comprise diffused first device light, diffused second device light, and diffused fifth device light (and optionally one or more of diffused fourth device light and diffused third device light)), and may have in specific embodiments a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

[0217] As indicated above, in embodiments the spectral power distribution of the system light may be controllable. In embodiments, the control system may be configured to control the spectral power distribution of the system light by controlling one or more of (a) a rotation of the birefringent rotator and (b) one or more of the first light generating device, the second light generating device, and the fifth light generating device (and optionally one or more of the fourth light generating device and the third light generating device) (i.e. the respective radiant flux(es)), and (c) one or more of a rotational position of the first light generating device (and optionally one or more of the fourth light generating device and the third light generating device). Herein, rotational positions of light generating devices especially refer to a rotation (of the light generating device) about the optical axis of the light emitted by the respective light generating device towards to the downstream configured polarization based redirecting optical element.

[0218] In embodiments, the fifth device light may have a fifth peak wavelength (Ap5) selected from the wavelength range of (380-780 nm, especially selected from the wavelength range of) 430-780 nm. Further, in embodiments the second device light may have a second peak wavelength (Ap2) selected from the wavelength range of 380-780 nm. In embodiments, peak wavelength of emission peaks of the fifth device light and second device light may differ at least 5 nm, such as at least 10 nm. In embodiments, peak wavelength of emission peaks of the fifth device light and second device light may differ at least 15 nm, such as at 2024PF80240

[0219] 53 least 20 nm. In specific embodiments, |Xp5-Xp2| > 10 nm (may apply). Further, in embodiments the fifth light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode.

[0220] Further, in embodiments the light generating system may be configured such that (a) the fourth multichroic based redirecting optical element may be configured in a lightreceiving relationship with both the second light generating device and the fifth light generating device, (b) the fourth multichroic based redirecting optical element may be configured to receive the second device light and fifth device light (151) and to direct (the second device light and fifth device light (151)) in an optical path to the diffuser arrangement via the first multichroic based redirecting optical element.

[0221] Note that in embodiments the second multichroic based redirecting optical element may be reflective for luminescent material light and transmissive for diffused device light, wherein the diffused device light comprises contributions of the second device light and the fifth device light, or the second multichroic based redirecting optical element may be transmissive for luminescent material light and reflective for diffused device light), wherein the diffused device light comprises contributions of the second device light and the fifth device light.

[0222] In specific embodiments, one of the second device light and the fifth device light may have a peak wavelength selected from the wavelength range of 430-490 nm, and the other one of the second device light and the fifth device light may have a peak wavelength selected from the wavelength range of 590-780 nm. However, other embodiments may also be possible.

[0223] Further, in embodiments the luminescent material may be selected to provide luminescent material light having spectral power within the wavelength range of 490-590 nm (especially having a centroid wavelength (ZLc) smaller than a peak wavelength of the second device light within the second wavelength range of 590-780 nm).

[0224] Therefore, in embodiments the light generating system may be configured to generate in an operational mode of the light generating system white system light comprising luminescent material light and diffused device light, wherein the diffused device light may comprise contributions from the second device light and optionally one or more of the first device light, the third device light, the fourth device light, and the fifth device light. For instance, the diffused device light may comprise contributions from the second device light and the first device light, and optionally one or more of the third device light, the fourth 2024PF80240

[0225] 54 device light, and the fifth device light. Of course, such options may only be possible when the respective light generating devices may be comprised by the system.

[0226] A solution for the thermal management of the luminescent material may be to, in embodiments, apply (or mount) the luminescent material onto a rotating element, such as e.g. a rotating (phosphor-)wheel (or disk) or a rotating rod (or cylinder). Such embodiments may enable thermal spreading and cooling without the need for e.g. active water cooling, and thereby enabling maximum possible irradiance values. Hence, in embodiments, the luminescent material may be configured onto a rotating element. Further, in embodiments, the diffuser may be a static diffuser. Alternatively, in embodiments, the diffuser may be a dynamic diffuser, such as e.g. a rotating wheel or a rotating rod, with a reflective diffuser track. In contrast to a static diffuser, a dynamic diffuser may provide improved thermal behavior and / or may reduce speckle of the diffused device light in the system output light, but may add bulk to the engine volume and rotating mass. Hence, in embodiments, the diffuser may (also) be configured onto a rotating element. In some embodiments, the luminescent material and the diffuser may each be configured on a separate rotating element. Alternatively, in embodiments, the luminescent material and the diffuser may be configured on the same rotating element, such as e.g. combined as separate rings on a rotating wheel or a rotating rod. Hence, in embodiments the system may further comprise a rotational element (or “rotating element”) and a rotator, wherein the rotational element may be configured to support one or more of the luminescent material and the diffuser. Especially, in embodiments the rotator may be configured to rotate the rotational element during an operational mode of the light generating system. In this way, the luminescent material and the diffuser, when supported by the rotational element, may be cooled, as in time, different parts of the luminescent material or diffuser, may be irradiated with the device light. In embodiments, the rotator may be controlled by the control system.

[0227] Further, in embodiments the system may comprise an out of plane mirror (M3), wherein the out of plane mirror (M3) may be configured downstream of the second multichroic based redirecting optical element and upstream of the light exit; wherein the out of plane mirror (M3) is configured to direct light received by the out of plane mirror (M3) (via the second multichroic based redirecting optical element) in a direction having an angle unequal to zero with a plane wherein the optical paths between (a) the first polarization based redirecting optical element and the first multichroic based redirecting optical element and (b) the first multichroic based redirecting optical element and the second multichroic based redirecting optical element are configured. This may allow creation of a relatively compact 2024PF80240

[0228] 55 system. For instance, it may allow for a shorter system building length as e.g. for common stage lighting fixtures, additional (zoom) projection optics (i.e., additional lenses, commonly comprising a large diameter final projection lens) are needed that consume a large fraction of the total available / acceptable fixture length. It also may provide compact / efficient heat sinking of the light generating devices, and efficient transfer of that heat to ambient, as the (output) optical path can be fully separated from the thermal transfer path(s). In embodiments, the out of plane mirror may have an angle of about 45° with the plane wherein the optical paths between (a) the first polarization based redirecting optical element and the first multichroic based redirecting optical element and (b) the first multichroic based redirecting optical element and the second multichroic based redirecting optical element are configured. However, other configurations may also be possible.

[0229] Further, some other embodiments are listed below.

[0230] In embodiments, the first light generating device may comprise a first laser bank comprising a plurality of first lasers, and / or the second light generating device may comprise a second laser bank comprising a plurality of second lasers. Further, in embodiments the optional third light generating device may comprise a third laser bank comprising a plurality of third lasers, and / or the optional fourth light generating device may comprise a fourth laser bank comprising a plurality of fourth lasers, and / or the optional fifth light generating device may comprise a fifth laser bank comprising a plurality of fifth lasers.

[0231] In embodiments, in the first operational mode of the light generating system the system light is white light having a correlated color temperature selected from the range of 2700-10000 K and a color rendering index of at least 65.

[0232] Further, in embodiments the luminescent material may be configured (i) in thermal contact with a thermally conductive material and / or (ii) onto a rotating element.

[0233] Hence, in embodiments, the light generating system may be configured to generate luminescent material light and / or diffused device light. In embodiments, the optics may be configured such that the luminescent material light may propagate via part of the optics to the light exit. For example, in some embodiments, the luminescent material light may propagate via one or more reflectors (comprised by the optics) to the light exit. Additionally or alternatively, in some embodiments, the luminescent material light may propagate via a second polarization based redirecting optical element (second polarizing beam splitter) (comprised by the optics, see also further below) to the light exit. Additionally or alternatively, in some embodiments, the luminescent material light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit. 2024PF80240

[0234] 56

[0235] Similarly, in embodiments, the optics may be configured such that the diffused device light may propagate via part of the optics to the light exit. For example, in some embodiments, the diffused device light may propagate via one or more reflectors (comprised by the optics) to the light exit. Additionally or alternatively, in some embodiments, the diffused device light may propagate via a second polarization based redirecting optical element (second polarizing beam splitter) (comprised by the optics, see also further below) to the light exit. Additionally or alternatively, in some embodiments, the diffused device light may propagate via a dichroic beam splitter (comprised by the optics, see also further below) to the light exit.

[0236] The light generating system may thus, in embodiments, be configured to provide in the first operational mode of the light generating system at the light exit one or more of luminescent material light and diffused device light. In other words, in such embodiments, (the system light comprising) one or more of luminescent material light and diffused device light may emanate away from the light generating system via the light exit. In embodiments, the light generating system may especially be configured to generate system light comprising one or more of at least part of the luminescent material light and at least part of the diffused device light.

[0237] Herein, the phrase “to combine X and Y into a same optical path” and similar phrases may refer to the respective beams of light being provided such, that their respective optical axes may be substantially parallel and / or may coincide. The term “optical axis” may especially be defined as an imaginary line that defines the path along which light propagates through a system. Especially, the optical axis may coincide with the direction of the light with the highest radiant flux. Therefore, in embodiments, the dichroic beam splitter may comprise one or more of a (flat or tile-shaped) dichroic mirror (e.g. a flat plat or tile comprising a dichroic coating), a dichroic cube (e.g. a cube comprising a diagonally oriented internal plane comprising a dichroic coating), and a dichroic sphere (e.g. a sphere comprising a cross-sectional internal plane comprising a dichroic coating). For example, in some embodiments, the luminescent material light and the diffused device light may be provided to the dichroic beam splitter from orthogonal directions, and the dichroic beam splitter may comprise a dichroic mirror configured to combine the (yellow) luminescent material light and the (blue) diffused device light into the same optical path.

[0238] The system may comprise a polarization converter. The polarization converter may, in embodiments, especially comprise a birefringent rotator. Especially, in embodiments, the polarization converter may comprise a X / 2 waveplate. In embodiments, the polarization converter may be configured to convert first device light comprising the first linear 2024PF80240

[0239] 57 polarization (e.g. p or s polarization) into first device light comprising the second linear polarization (e.g. s or p polarization). Additionally or alternatively, in embodiments, the polarization converter may be configured to convert first device light comprising the second linear polarization (e.g. s or p polarization) into first device light comprising the first linear polarization (e.g. p or s polarization). Hence, in embodiment the polarization converter comprises (or is) a birefringent rotator.

[0240] Though not further described herein, in specific embodiments it may be possible to add device light from a further light generating devices in the optical path from the first polarization based redirecting optical element to the luminescent material arrangement. This may be done via multichroic multiplexing and / or polarization multiplexing. Further, alternatively or additionally, though not further described herein, in specific embodiments it may be possible to add device light from a(nother) further light generating devices in the optical path from the first multichroic based redirecting optical element to the diffuser arrangement. This may be done via multichroic multiplexing and / or polarization multiplexing.

[0241] As indicated above, the light generating system may comprise optics. The term “optics” may especially refer to (one or more) optical elements. Hence, the terms “optics” and “optical elements” may refer to the same items. The optics may include one or more of (specular or surface textured) mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, selectively reflective and / or selectively transmissive optics, arrays of one or more of the afore-mentioned, etc. Alternatively or additionally, the term “optics” may refer to a holographic element or a mixing rod. In embodiments, the optics may include one or more of beam expander optics and zoom lens optics. See further above for examples of optics. In embodiments, the optics may comprise an integrator, like a “Koehler integrator” (or “Kohler integrator”).

[0242] In specific embodiments, the optics may comprise one or more of a homogenizing optics, collimating optics, condensing optics, and reflecting optics. For example, in embodiments, the luminescent material light and the diffused laser light may be provided (e.g. by the dichroic beam splitter or the beam splitter arrangement as defined above) along the same optical path to the light exit, and the optics may comprise a beam homogenizer configured upstream of the light exit and configured to combine and homogenize the received light and to provide (homogenized white) system light to the light exit. 2024PF80240

[0243] 58

[0244] As indicated above, in embodiments, the light generating system may comprise laser banks. As beams of light emitted from such (multi-chip packages and / or) laser banks may comprise multiple narrow laser beams, each individual laser beam may represent a hot spot in the beam of device light. Focusing of such a beam of device light on e.g. a luminescent material may exceed the maximum tolerable local irradiance and result in damage to the luminescent material, or other materials present in the luminescent material arrangement. Therefore, in some embodiments, homogenizing optics may be applied and may especially be configured between (relative to the propagation of light through the system) the light generating devices (contributing to irradiation of the luminescent material) and collimating optics of the luminescent material, see also below. Similarly, in some embodiments, homogenizing optics may be applied and may especially be configured between (relative to the propagation of light through the system) the light generating devices (contributing to irradiation of the diffuser) and collimating optics of the diffuser, see also below. In embodiments, the homogenizing optics may e.g. comprise one or more of a transmissive volume diffuser, a transmissive surface diffuser, a reflective surface diffuser, a transmissive or reflective diffractive optical element, a transmissive holographic optical element, a single multi lens array, a double multi lens array such as a fly-eye lens array, or an integrating polygonal light pipe that may be either solid (with propagation in the integrator based on total internal reflection) or hollow (with propagation in the integrator based on specular reflection).

[0245] In embodiments, the condensing optics may 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 the 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. Further, in embodiments, 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. Especially, in embodiments, the first collecting and collimating optics and the second collecting and collimating optics may each comprise at least one positive lens, especially at least two positive lenses. In embodiments, 2024PF80240

[0246] 59 the collimating optics and / or condensing optics, especially the lenses, may comprise glass materials, such as e.g. N-BK7, H-K51, B270, or fused silica (FS). The latter shows relatively low absorption and relatively low induced stress, but also has a relatively low refractive index. Therefore, if FS is used for all the lenses, in embodiments, the condensing optics for the reflective mode may preferably comprise three lenses.

[0247] The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs.

[0248] Further, the term “light source” may in embodiments also refer to a so-called chips-on-board (COB) light source. The term “COB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light source may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module.

[0249] The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm. Herein, the term p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.

[0250] The light source may have a light escape surface. For LED’s it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the 2024PF80240

[0251] 60 resin. In principle, it may also be the terminal end of a fiber. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source.

[0252] Likewise, a light generating device may comprise a light escape surface, such as an end window. Further, likewise a light generating system may comprise a light escape surface, such as an end window.

[0253] The term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser, etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED).

[0254] The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, such as an LED, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise an LED with on-chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering).

[0255] In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs.

[0256] The light source may especially be configured to generate light source light having an optical axis (O), (a beam shape,) and a spectral power distribution. The light source light may in embodiments comprise one or more bands, e.g. having band widths as known for lasers.

[0257] The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as 2024PF80240

[0258] 61 a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device).

[0259] The term “light source” herein may also refer to a light source comprising a solid state light source, such as an LED or a laser diode or a superluminescent diode.

[0260] The term “light source” may (thus) in embodiments also refer to a light source that is (also) based on conversion of light, such as a light source in combination with a luminescent converter material. Hence, the term “light source” may also refer to a combination of an LED with a luminescent material configured to convert at least part of the LED radiation, or to a combination of a (diode) laser with a luminescent material configured to convert at least part of the (diode) laser radiation.

[0261] In embodiments, the term “light source” may also refer to a combination of a light source, like an LED, and an optical filter, which may change the spectral power distribution of the light generated by the light source. Especially, the term “light generating device” may be used to address a light source and further (optical components), like an optical filter and / or a beam shaping element, etc.

[0262] The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin.

[0263] The term “solid state light source”, or “solid state material light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a diode laser, or a superluminescent diode.

[0264] The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the spectral wavelength range of 200-2000 nm, such as 300-1500 nm. The term “laser” especially refers 2024PF80240

[0265] 62 to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.

[0266] Especially, in embodiments the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, refer to a laser diode (or diode laser).

[0267] Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of cerium doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium doped chrysoberyl (alexandrite) laser, chromium ZnSe (CrZnSe) laser, divalent samarium doped calcium fluoride (Sm:CaF2) laser, Er:YAG laser, erbium doped and erbium-ytterbium codoped glass lasers, F-Center laser, holmium YAG (Ho: YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium doped yttrium calcium oxoborate Nd:YCa4O(BO3)3 or Nd:YCOB, neodymium doped yttrium orthovanadate (Nd:YVO4) laser, neodymium glass (Nd:glass) laser, neodymium YLF (Nd:YLF) solid-state laser, promethium 147 doped phosphate glass (147Pm3+:glass) solid-state laser, ruby laser (AhO3:Cr3+), thulium YAG (Tm:YAG) laser, titanium sapphire (Ti:sapphire; AhCEHi3) laser, trival ent uranium doped calcium fluoride (U:CaF2) solid-state laser, Ytterbium doped glass laser (rod, plate / chip, and fiber), Ytterbium YAG (Yb:YAG) laser, Yb2O3 (glass or ceramics) laser, etc.

[0268] For instance, including second and third harmonic generation embodiments, the light source may comprise one or more of an F center laser, an yttrium orthovanadate (Nd:YVO4) laser, a promethium 147 doped phosphate glass (147Pm3+:glass), and a titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser. For instance, considering second and third harmonic generation, such light sources may be used to generated blue light.

[0269] In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of a semiconductor laser diodes, such as GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc. Suitable solid state lasers may be selected from (III-V compound) semiconductor lasers, such as in specific embodiments semiconductor lasers selected from the group of GaN, AlGaN, InGaN, and AlGalnN, (especially for blue-green), GaP, InP, GalnP, and AlGalnP (especially for red-NIR), GaAs, AlGaAs, InGaAs, and InGaAsP (especially for NIR-MIR). Hence, in embodiments one or more of the light generating devices may comprise a semiconductor laser selected from the group of GaN, AlGaN, InGaN, AlGalnN, GaP, InP, GalnP, and AlGalnP lasers. 2024PF80240

[0270] 63

[0271] A laser may be combined with an upconverter in order to arrive at shorter (laser) wavelengths. For instance, with some (trivalent) rare earth ions upconversion may be obtained or with non-linear crystals upconversion can be obtained. Alternatively, a laser can be combined with a downconverter, such as a dye laser, to arrive at longer (laser) wavelengths.

[0272] As can be derived from the below, the term “laser light source” may also refer to a plurality of (different or identical) laser light sources. In specific embodiments, the term “laser light source” may refer to a plurality N of (identical) laser light sources. In embodiments, N=2, or more. In specific embodiments, N may be at least 5, such as especially at least 8. In this way, a higher brightness may be obtained. In embodiments, laser light sources may be arranged in a laser bank (see also above). The laser bank may in embodiments comprise heat sinking and / or optics e.g. a lens to collimate the laser light. Hence, in embodiments lasers in a laser bank (or “laser array bank”) may share the same optics.

[0273] The laser light source is configured to generate laser light source light (or “laser light”). The light source light may essentially consist of the laser light source light. The light source light may also comprise laser light source light of two or more (different or identical) laser light sources. For instance, the laser light source light of two or more (different or identical) laser light sources may be coupled into a light guide, to provide a single beam of light comprising the laser light source light of the two or more (different or identical) laser light sources. In specific embodiments, the light source light is thus especially collimated light source light. In yet further embodiments, the light source light is especially (collimated) laser light source light.

[0274] The laser light source light may in embodiments comprise one or more bands, having band widths as known for lasers. In specific embodiments, the band(s) may be relatively sharp line(s), such as having full width half maximum (FWHM) in the range of less than 20 nm at RT, such as equal to or less than 10 nm. Hence, the light source light has a spectral power distribution (intensity on an energy scale as function of the wavelength) which may comprise one or more (narrow) bands.

[0275] The beams (of light source light) may be focused or collimated beams of (laser) light source light. The term “focused” may especially refer to converging to a small spot. This small spot may be at the discrete converter region, or (slightly) upstream thereof or (slightly) downstream thereof. Especially, focusing and / or collimation may be such that the cross-sectional shape (perpendicular to the optical axis) of the beam at the discrete converter 2024PF80240

[0276] 64 region (at the side face) is essentially not larger than the cross-section shape (perpendicular to the optical axis) of the discrete converter region (where the light source light irradiates the discrete converter region). Focusing may be executed with one or more optics, like (focusing) lenses. Especially, two lenses may be applied to focus the laser light source light. Collimation may be executed with one or more (other) optics, like collimation elements, such as lenses and / or parabolic mirrors. In embodiments, the beam of (laser) light source light may be relatively highly collimated, such as in embodiments <2° (FWHM), more especially <1° (FWHM), most especially <0.5° (FWHM). Hence, <2° (FWHM) may be considered (highly) collimated light source light. Optics may be used to provide (high) collimation (see also above).

[0277] The term “solid state material laser”, and similar terms, may refer to a solid state laser like based on a crystalline or glass body doped with ions, like transition metal ions and / or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, such as e.g. a vertical cavity surface-emitting laser (VCSEL), etc.

[0278] The term “solid state light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode.

[0279] Instead of the term “solid state light source” also the term “semiconductorbased light source” may be applied. Hence, the term “semiconductor-based light source” may e.g. refer to one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode. Hence, the light generating device may comprise one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.

[0280] A light-emitting diode (LED) is especially a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor may recombine with electron holes, releasing energy in the form of photons. The color of the light (corresponding to the energy of the photons) may be determined by the energy required for electrons to cross the band gap of the semiconductor.

[0281] A laser diode (or diode laser) may be a semiconductor device substantially similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. This is known to a person skilled in the art.

[0282] Superluminescent diodes are known in the art. A superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like an LED, while having a brightness about in between the brightness of LEDs and laser diodes. Superluminescent diodes are e.g. described in US2020192017, 2024PF80240

[0283] 65 incorporated herein by reference, or in “Edge Emitting Laser Diodes and Superluminescent Diodes”, Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Naj da, Thomas Slight, Piotr Perlin, Book Editor(s): Fabrizio Roccaforte, Mike Leszczynski, First published: 03 August 2020 https: / / doi.org / 10.1002 / 9783527825264.ch9 in chapter 9,3 superluminescent diodes. This book, and especially chapter 9.3, are herein incorporated by reference. Superluminescent diodes may combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode.

[0284] The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

[0285] The terms “visible”, “visible light” or “visible emission” and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. Herein, UV may especially refer to a wavelength selected from the range of 190-380 nm, such as 200-380 nm. Herein, IR (infrared) may especially refer to radiation having a wavelength selected from the range of 780-3000 nm, such as 780-2000 nm, e.g. a wavelength up to about 1500 nm, like a wavelength of at least 900 nm, though in specific embodiments other wavelengths may also be possible.

[0286] 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 2024PF80240

[0287] 66 embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.

[0288] The terms “blue light” or “blue emission” especially relates to light having a wavelength in the range of about 440-495 nm (including some violet and cyan hues). 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 terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

[0289] In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the light generating devices, the luminescent material arrangement, the diffuser arrangement, and the optics. In embodiments, the invention may thus comprise an optical wireless communication device comprising the light generating system. 2024PF80240

[0290] 67

[0291] In yet a further aspect, the invention also provides a lighting fixture comprising the light generating system as defined herein.

[0292] In yet a further aspect, the light generating system may comprise a device selected from the group of a lamp, a luminaire, or a lighting fixture, wherein the lamp, luminaire, or lighting fixture may comprise one or more elements of the light generating system, such as the light generating devices, the luminescent material arrangement, the diffuser arrangement, the optics, and the light exit, and the light generating system may further comprise e.g. a control system configured to control the device.

[0293] The term “lighting fixture” may refer to a light emitting system like a moving head, a search light, a stage light, etc. Generally these fixtures may have various control options for changing one or more of the direction of the light (e.g. via gimbals or rotary stages), the beam angle / width (e.g. via zoom optics), the beam pattern (e.g. via mechanical selection of a specific aperture that defines a virtual and patterned source for the further projection optics), the color of the light (e.g. via mechanical selection of a certain color filter), and of course the luminous flux, and mostly these are remotely controllable.

[0294] BRIEF DESCRIPTION OF THE DRAWINGS

[0295] 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:

[0296] Figs. 1-6 schematically depict some embodiments of the light generating system; and

[0297] Fig. 7 schematically depicts some applications of the light generating system in lighting devices.

[0298] The schematic drawings are not necessarily to scale.

[0299] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0300] Figs. 1-6 schematically depict embodiments of the light generating system 1000. However, each of the schematical drawings may include a combination of variants, which are not necessarily coupled (see further also below). Hence, the invention is not limited to the herein depicted schematical drawings.

[0301] Referring to Figs. 1-6, in specific embodiments, the invention provides a light generating system 1000 comprising light generating devices 100, a luminescent material arrangement 2000, a diffuser arrangement 7000, optics 500, optionally a control system 300, 2024PF80240

[0302] 68 and a light exit 1090. In further embodiments, the light generating devices 100 may comprise (i) a first light generating device 110 configured to generate first device light 111, and (ii) a second light generating device 120 configured to generate second device light 121. In yet further embodiments, the first light generating device 110 and the second light generating device 120 may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. Further, in embodiments, the luminescent material arrangement 2000 may comprise a luminescent material 200 configured to convert at least part of first device light 111 received by the luminescent material 200 into luminescent material light 201. Especially, the diffuser arrangement 7000 may comprise a diffuser 700 configured to diffuse second device light 121 and first device light 111 received by the diffuser 700 into diffused device light 701. Furthermore, in embodiments, the optics 500 may comprise a first polarization based redirecting optical element 511 configured downstream of the first light generating device 110 and upstream of both the luminescent material arrangement 2000 and the diffuser arrangement 7000. Moreover, in embodiments, the light generating system 1000 may be configured such that the first device light 111 received by the first polarization based redirecting optical element 511 may comprise linear polarized light. Yet, in embodiments, the first polarization based redirecting optical element 511 may be configured to direct first device light 111 in dependence of its (linear) polarization to one or more of the luminescent material arrangement 2000 and the diffuser arrangement 7000. Especially, the optics 500 (further) may comprise a first multichroic based redirecting optical element 521 configured (a) in an optical path between the first polarization based redirecting optical element 511 and the diffuser arrangement 7000 and (b) in an optical path between the second light generating device 120 and the diffuser arrangement 7000. In further embodiments, the first multichroic based redirecting optical element 521 may be configured to direct (i) first device light 111 received via the first polarization based redirecting optical element 511, and (ii) second device light 121 received from the second light generating device 120 in an optical path to the diffuser arrangement 7000. Yet, in embodiments, the optics 500 may comprise a second multichroic based redirecting optical element 522 configured (a) in an optical path between the first polarization based redirecting optical element 511 and the luminescent material arrangement 2000, (b) in an optical path between the luminescent material arrangement 2000 and the light exit 1090, and (c) in an optical path between the diffuser arrangement 7000 and the light exit 1090. In further embodiments, the second multichroic based redirecting optical element 522 may be configured to direct (i) luminescent material light 201, received by the second multichroic based redirecting optical 2024PF80240

[0303] 69 element 522, and (ii) diffused device light 701, received by the second multi chroic based redirecting optical element 522, in an (mutual) optical path to the light exit 1090. Especially, the light generating system 1000 may be configured to provide, via the light exit 1090, system light 1001. Moreover, in embodiments, the control system 300 may be configured to control the system light 1001. In further embodiments, the system light 1001 in a first operational mode of the light generating system 1000 may comprise at least part of the luminescent material light 201 and at least part of the diffused device light 701, and may have a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

[0304] In yet further embodiments, the light generating system 1000 may further comprise a polarization control system 600. In embodiments, the polarization control system 600 may be configured to control a polarization of the first device light 111 reaching the first polarization based redirecting optical element 511, thereby controlling a power distribution of the first device light 111 over the optical paths to the luminescent material arrangement 2000 and the diffuser arrangement 7000. Further, in embodiments, the polarization control system 600 may comprise one or more of: (a) a birefringent rotator 610 configured downstream of the first light generating device 110 and upstream of the first polarization based redirecting optical element 511, and b) an actuator 630 configured to rotate the first light generating device 110.

[0305] Yet further, in embodiments, the polarization control system 600 may be configured to control rotation of the birefringent rotator 610. In further embodiments, the birefringent rotator 610 may comprise a X / 2 waveplate; (. To this end, the polarization control system may comprise a device configured to move, such as rotate, the birefringent rotator 610. This device is indicated with reference 640, and is schematically depicted in Figs. 2, 3, 5, and 6. Device 640 may comprise an actuator.

[0306] Moreover, in embodiments, the polarization control system 600 may be configured to control the actuator 630. As indicated above, the actuator 630 may be configured to rotate the first light generating device 110. This embodiment is schematically depicted in Figs. 1 and 4.

[0307] Further, in embodiments, the control system 300 may be configured to control a spectral power distribution of the system light 1001 by controlling one or more of (i) the polarization control system 600 and (ii) one or more of the light generating devices 100.

[0308] As indicated above, in alternative embodiments the spectral power distribution may be fixed, like factory set, or in yet alternative embodiments, only controllable via the 2024PF80240

[0309] 70 radiant fluxes of the light generating devices (first light generating device 110 and / or second light generating device 120, and optional further light generating devices selected from the third light generating device, the fourth light generating device, and the fifth light generating device). Yet, as indicated above, a further option of control may be via the polarization control system 600, which has two options to do so (see above).

[0310] In embodiments, the optics 500 may (further) comprise a second polarization based redirecting optical element 512. In embodiments, the diffuser arrangement 7000 may be configured as colinear arrangement. In further embodiments, incoming second device light 121, received by the diffuser arrangement 7000, and incoming first device light 111, received by the diffuser arrangement 7000, may propagate over at least part of its optical path colinear with an optical path of the diffused device light 701 propagating from the diffuser arrangement 7000 to the light exit 1090.

[0311] In a colinear arrangement, device light propagating to the diffuser 700 may have an optical axis parallel to a normal N to the diffuser (surface), and diffused device light 701 may also have an optical axis parallel to a normal N to the diffuser (surface).

[0312] Furthermore, in embodiments, the diffuser 700 may comprise a polarization maintaining diffuser. Furthermore, in embodiments, the diffuser arrangement 7000 may further comprise a X / 4 waveplate 710 configured between the second polarization based redirecting optical element 512 and the diffuser 700. Yet, in embodiments, the second polarization based redirecting optical element 512 may be configured to direct second device light 121, received by the second polarization based redirecting optical element 512, and first device light 111, received by the second polarization based redirecting optical element 512, to the X 4 waveplate 710. In further embodiments, the X / 4 waveplate 710 may be configured to convert linear polarized light received by the X / 4 waveplate 710 into elliptical polarized light and to convert elliptical polarized light received by the X / 4 waveplate 710 into linear polarized light. In yet further embodiments, the second polarization based redirecting optical element 512 may be configured (a) in an optical path between the first multichroic based redirecting optical element 521 and the diffuser arrangement 7000, and (b) in an optical path between the diffuser arrangement 7000 and the second multichroic based redirecting optical element 522. Further, in embodiments, the second polarization based redirecting optical element 512 may be configured to (i) direct (linearly polarized) second device light 121, received by the second polarization based redirecting optical element 512 (via the first multichroic based redirecting optical element 521), and first device light 111, received by the second polarization based redirecting optical element 512 (via the first multichroic based 2024PF80240

[0313] 71 redirecting optical element 521), to the diffuser arrangement 7000, and (ii) direct (linearly polarized) diffused device light 701 received from the diffuser arrangement 7000 in an optical path to the second multichroic based redirecting optical element 522. Furthermore, in embodiments, the light generating system 1000 may be configured such that the second device light 121 received by the second polarization based redirecting optical element 512 may comprise linear polarized light.

[0314] Referring to Figs. 2 and 3, in further embodiments, the diffuser arrangement 7000 may be configured as non-colinear arrangement. Moreover, in embodiments, the light generating system 1000 may be configured such that incoming light, which may comprise second device light 121 and optional first device light 111, on the diffuser 700, may have an optical axis (Oi) having a first angle (ai) with a normal to the diffuser 700 unequal to 0°. Furthermore, in embodiments, outgoing diffused device light 701 may have an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser 700 unequal to 0°. Moreover, in embodiments, the optical axes (Oi,Oo) may have a mutual angle (P) unequal to 0°. In Figs. 1, and 4-6, first angle ai and second angel ao may essentially be 0°, and thus the mutual angle P may also essentially be 0° (or 180°).

[0315] Furthermore, in embodiments, the first device light 111 and the second device light 121 may have different spectral power distributions. In further embodiments, the first device light 111 may have a first peak wavelength (Xp l ) selected from the wavelength range of 430-490 nm. Especially, the second device light 121 may have a second peak wavelength (Xp2) selected from the wavelength range of 380-780 nm. In further embodiments, |Xpl-Xp2| > 10 nm.

[0316] In further embodiments, the first polarization based redirecting optical element 511 may comprise a polarizing beam splitter or a partial polarizing beam splitter. In yet further embodiments, for the first polarization based redirecting optical element 511 one of the following applies: (a) the first polarization based redirecting optical element 511 may be fully reflective for s-polarized blue device light and fully transmissive for p-polarized blue device light; (b) the first polarization based redirecting optical element 511 may be fully transmissive for p-polarized blue device light and partly transmissive (and partly reflective) for s-polarized blue device light; (c) the first polarization based redirecting optical element 511 may be fully reflective for s-polarized blue device light and partly transmissive (and partly reflective) for p-polarized blue device light; (d) the first polarization based redirecting optical element 511 may be partly reflective and partly transmissive for both s-polarized and p-polarized blue device light. The latter option (iv) may especially be possible if there are no 2024PF80240

[0317] 72 polarization requirements for the light directed from the first polarization based redirecting optical element into the diffusion channel. Especially, the polarization may be referenced to a splitting plane of the polarizing beam splitter or the partial polarizing beam splitter. Furthermore, in embodiments, the splitting plane may be a plane at which the polarization based beam splitting (i.e., transmission and reflection) takes place.

[0318] Referring to these aforementioned options, option (b) may require that (i) s- polarized first device light I l l is directed by the first polarization based redirecting optical element 511 to the diffuser arrangement 7000 (i.e., to second polarization based redirecting optical element 512) and (ii) the first polarization based redirecting optical element 511 is configured to transmit first device light to the luminescent material arrangement 2000 and to reflect (at least a portion of) first device light to the diffuser arrangement 7000, while option (c) may require that (i) p-polarized first device light is directed by the first polarization based redirecting optical element 511 to second polarization based redirecting optical element 512 and (ii) the first polarization based redirecting optical element 511 is configured to reflect first device light to the luminescent material arrangement 2000 and to transmit (at least a portion of) first device light to the diffuser arrangement 7000. For option (d) the diffuser arrangement 7000 may need to comprise a non-colinear diffuser arrangement or a transmissive diffuser arrangement. For option (a) if the first polarization based redirecting optical element 511 is configured to direct (i.e., to reflect) s-polarized first device light to the diffuser, then the diffuser arrangement 7000 may need to be configured such that second polarization based redirecting optical element 512 reflects first device light to the diffuser, and if the first polarization based redirecting optical element 511 is configured to direct p- polarized fist device light to the diffuser, then the diffuser arrangement 7000 may need to be configured such that second polarization based redirecting optical element 512 transmits first device light to the diffuser.

[0319] References Ml and M2 indicated specular mirrors (specular reflectors).

[0320] Referring to Figs. 2-6, in further embodiments, the light generating system 1000 may (also) comprise a third light generating device 130. Especially, in embodiments, the third light generating device 130 may be configured to generate third device light 131.

[0321] In specific embodiments, the third device light 131 may have spectral power in the wavelength range of 380-490 nm, especially selected from the wavelength range of 430- 490 nm). Especially, the third light generating device 130 may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode. 2024PF80240

[0322] 73

[0323] Especially, such as referring to the embodiment of Fig. 3, the light generating system 1000 may be configured such that (a) the first polarization based redirecting optical element 511 may be configured in a light-receiving relationship with the third light generating device 130, and (b) the third device light 131 received by the first polarization based redirecting optical element 511 may comprise linear polarized light. In further embodiments, the first polarization based redirecting optical element 511 may be configured to direct at least part of the third device light 131 (in dependence of its (linear) polarization) in an optical path to the luminescent material arrangement 2000.

[0324] Further, in embodiments, the second device light 121 may have a second peak wavelength (Ap2) selected from the wavelength range of 590-780 nm.

[0325] Moreover, in embodiments, the light generating system 1000 may be configured to generate in an operational mode of the light generating system 1000 white system light 1000 comprising luminescent material light 201 and diffused device light 701. Especially, the diffused device light 701 may comprise contributions from the first device light 111 and the second device light 121.

[0326] The optics 500 may e.g. comprise condenser lenses 540. Further, the optics may comprise transmissive integrator lenses 530 (which may be provided with different shapes (as known in the art)).

[0327] Moreover, referring to e.g. Figs. 2, 3, 5 and 6, in embodiments, the control system 300, may be configured to control the spectral power distribution of the system light 1001 by controlling one or more of (a) a rotation of the birefringent rotator 610 (via the (actuator) device 640) and (b) one or more of the first light generating device 110, the second light generating device 120, and the third light generating device 130, and optionally further light generating devices 100, such as e.g. the fifth light generating device 150 as schematically depicted in Fig. 6.

[0328] Moreover, referring to e.g. Figs. 1 and 4, in embodiments, the control system 300, may be configured to control the spectral power distribution of the system light 1001 by controlling one or more of (a) a rotation of the first light generating device 110 (via the actuator device 630 and (b) one or more of the first light generating device 110, the second light generating device 120, and the third light generating device 130, and optionally further light generating devices 100, such as e.g. the fourth light generating device 140 as schematically depicted in Fig. 4.

[0329] Especially referring to e.g. Fig. 3, though this embodiment is not limited to the embodiment of Fig. 3 only, in further embodiments, the second light generating device 120 2024PF80240

[0330] 74 may be configured to generate primary second device light 121a having spectral power in a first wavelength range of 430-490 nm and secondary second device light 121b having spectral power in a second wavelength range of 590-780 nm. Further, in embodiments, in an operational mode of the light generating system 1000, the diffused device light 701 may comprise contributions of the primary second device light 121a and the secondary second device light 121b.

[0331] Further, in embodiments, referring to Fig. 3, the second multichroic based redirecting optical element 522 may be transmissive for luminescent material light 201 and reflective for diffused device light 701. However, it may also be the other way around.

[0332] Furthermore, in embodiments, the luminescent material 200 may be selected to provide luminescent material light 201 having spectral power within the wavelength range of 490-590 nm, especially having a centroid wavelength (XLc) having a wavelength smaller than a peak wavelength of the second device light 121 within the second wavelength range of 590-780 nm.

[0333] Referring to especially Figs. 2-3, in embodiments, the diffuser arrangement 7000 may be configured as non-colinear arrangement. However, the embodiments of Figs. 2- 3 could also be adapted to include a colinear diffuser arrangement (or transmissive diffuser arrangement).

[0334] Referring to especially Figs. 2-3, in embodiments the polarization control system 600 may comprise the birefringent rotator 610. As indicated above, other embodiments may also be possible.

[0335] Referring to e.g. the embodiments schematically depicted in Figs. 4-5, in further embodiments, the light generating system 1000 may further comprise a fourth light generating device 140 and a third multichroic based redirecting optical element 523. Especially, the fourth light generating device 140 may be configured to generate fourth device light 141. In further embodiments, the fourth light generating device 140 may comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode. Furthermore, in embodiments, the light generating system 1000 may be configured such that (a) the first polarization based redirecting optical element 511 may be configured in a light-receiving relationship with the fourth light generating device 140, (b) the fourth device light 141 received by the first polarization based redirecting optical element 511 may comprise linear polarized light, and (c) the third multichroic based redirecting optical element 523 may be configured (i) downstream the fourth light generating device 140 and (ii) upstream of the first polarization based redirecting optical element 511. In 2024PF80240

[0336] 75 further embodiments, the third multichroic based redirecting optical element 523 may be configured to receive fourth device light 141 and to direct (at least part of the received) fourth device light 141 to the first polarization based redirecting optical element 511. In yet further embodiments, the first polarization based redirecting optical element 511 may be configured to direct (at least part of the first device light 111 received by the first polarization based redirecting optical element 511 and) at least part of the fourth device light 141 received by the first polarization based redirecting optical element 511 (and optionally at least part of the third device light 131 from the third light generating device 130, received by the first polarization based redirecting optical element 511) (in dependence of the polarization) in an optical path to the luminescent material arrangement 2000.

[0337] Referring to Figs. 4-5, the first polarization based redirecting optical element 511 receives from two orthogonal branches device light. Note that these branches may also be interchanged. As indicated above, this also applies to Figs. 2-3, and 6.

[0338] Substantially likewise, but referring to Fig. 4, this may apply to the third multichroic based redirecting optical element 523, which receives from two orthogonal branches device light, which may also be interchanged. Hence, in this respect only, already four permutations may be possible, of which only one is depicted in Fig. 5.

[0339] In specific embodiments, the fourth device light 141 may have a fourth peak wavelength (Ap4) selected from the wavelength range of 380-490 nm, more especially selected from the wavelength range of 430-490 nm. Furthermore, in embodiments, the first device light 111 may have a first peak wavelength (kp l ) selected from the wavelength range of 430-490 nm. Especially, in embodiments | Ap4-kp l | > 10 nm may apply.

[0340] Furthermore, referring to Fig. 4, in embodiments, the third multichroic based redirecting optical element 523 may be configured (i) downstream of both the first light generating device 110 and the fourth light generating device 140 and (ii) upstream of the first polarization based redirecting optical element 511. In specific embodiments, the third multichroic based redirecting optical element 523 may be configured to receive first device light 111 and fourth device light 141 and to direct first device light 111 and fourth device light 141 to the first polarization based redirecting optical element 511. Furthermore, referring to Fig. 4, in alternative embodiments, the third multichroic based redirecting optical element 523 may be configured (i) downstream of both the first light generating device 110 and the third generating device 130 and (ii) upstream of the first polarization based redirecting optical element 511. In specific embodiments, the third multichroic based redirecting optical element 523 may be configured to receive first device light 111 and third 2024PF80240

[0341] 76 device light 131 and to direct first device light 111 and third device light 131 to the first polarization based redirecting optical element 511. Other embodiments, however, may also be possible. In alternative embodiments, the third multichroic based redirecting optical element 523 may be configured (i) downstream of both the fourth light generating device 140 and the third generating device 130 and (ii) upstream of the first polarization based redirecting optical element 511. In specific embodiments, the third multichroic based redirecting optical element 523 may be configured to receive fourth device light 141 and third device light 131 and to direct fourth device light 141 and third device light 131 to the first polarization based redirecting optical element 511.

[0342] Hence, in embodiments the first polarization based redirecting optical element 511 may be at least partially transmissive for the linear polarization of the third device light 131, and at least partially reflective for the linear polarization of the fourth device light 141).

[0343] Alternatively (i.e., in case the third light generating devices 130 is configured upstream of the third multichroic based redirecting optical element 523 in Fig. 4, at least partially reflective for the linear polarization of the third device light 131 and the fourth device light 141. Or, alternatively (i.e., in case the two optical branches upstream of 511 in Fig. 4 are exchanged), at least partially reflective for the linear polarization of the third device light 131 and at least partially transmissive for the linear polarization of first and fourth device light 141. Or, alternatively (i.e., in case the two optical branches upstream of 511 in Fig. 4 are exchanged and 130 is configured upstream of the third multichroic based redirecting optical element 523), at least partially transmissive for the linear polarization of the third device light 131 and the fourth device light 141.

[0344] Further, referring to e.g. Fig. 4, but also to e.g. Figs. 1, 5, and 6, in embodiments, the diffuser arrangement 7000 may be configured as colinear arrangement.

[0345] Referring to Fig. 4, but also the embodiments of Figs. 2-3 and 5-6, especially, the light generating system 1000 may comprise the third light generating device 130. In further embodiments, the third device light 131 reaching the first polarization based redirecting optical element 511 may comprise a linear polarization complementary to the fourth device light 141, though in other configurations (see e.g. one or more of the permutations indicated above), the third device light 131 reaching the first polarization based redirecting optical element 511 may comprise the same linear polarization as the fourth device light 141.

[0346] Also referring to e.g. Fig. 4, in embodiments, the first polarization based redirecting optical element 511 may be at least partially transmissive for the linear 2024PF80240

[0347] 77 polarization of the third device light 131, and at least partially reflective for the linear polarization of the fourth device light 141, though in other configurations (see e.g. one or more of the permutations indicated above), this may be different.

[0348] Referring especially to e.g. Fig. 5, in embodiments, the light generating system 1000 may further comprise a rotational element 1250 and a rotator 1240. In embodiments, the rotational element 1250 may be configured to support the luminescent material 200 and the diffuser 700. In further embodiments, the rotator 1240 may be configured to rotate the rotational element 1250 during an operational mode of the light generating system 1000. In other embodiments, however, the rotational element 1250 may be configured to support the luminescent material 200 only. In yet other embodiments, the rotational element 1250 may be configured to support diffuser 700 only. The rotator 1240 may e.g. comprise a (rotational) actuator. Here, reference AR refers to a rotational axis of the rotational element 1250. R2 refers to radii related to the diffuser 700 and R1 refers to radii associated to the luminescent material 200. In general, the radii R2 related to the diffuser 700 are either larger or smaller than the radii R1 associated to the luminescent material 200 (here R1>R2). The larger outer track for the luminescent material 200 may also be beneficial in view of thermal management. Note that the rotator 1240 may also comprise a thermally conductive material (see for embodiments of thermally conductive materials above).

[0349] Note that the rotation element 1250, as schematically depicted in Fig. 5, as well as its (indicated) variants, may also be applied in the embodiments schematically depicted in Figs. 1-4 and 6.

[0350] Further, in embodiments the light generating system 1000 may further comprise an out of plane mirror M3. This is schematically depicted in Fig. 5. Note that the out of plane mirror M3, as schematically depicted in Fig. 5, may also be applied in the embodiments schematically depicted in Figs. 1-4 and 6. In embodiments, the out of plane mirror M3 may be configured downstream of the second multichroic based redirecting optical element 522 and upstream of the light exit 1090. Moreover, in embodiments, the out of plane mirror M3 may be configured to direct light received by the out of plane mirror M3 (via the second multichroic based redirecting optical element 522) in a direction having an angle unequal to zero with a plane wherein the optical paths between (a) the first polarization based redirecting optical element 511 and the first multichroic based redirecting optical element 521 and (b) the first multichroic based redirecting optical element 521 and the second multichroic based redirecting optical element 522 may be configured. Especially, out of plane mirror M3 is also a specular mirror. 2024PF80240

[0351] 78

[0352] Referring to Fig. 6, in further embodiments, the light generating system 1000 may (also) comprise a fifth light generating device 150 and a fourth multi chroic based redirecting optical element 524. Especially, the fifth light generating device 150 may be configured to generate fifth device light 151.

[0353] Moreover, in embodiments, the fifth device light 151 may have a fifth peak wavelength (Zp5) selected from the wavelength range of 380-780 nm, especially selected from the wavelength range of 430-780 nm. Further, in embodiments the second device light 121 may have a second peak wavelength (Zp2) selected from the wavelength range of 380- 780 nm. Further, in embodiments, |Xp5-Xp2| > 10 nm. Further, in embodiments, the fifth light generating device 150 may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode.

[0354] Further, in embodiments, the light generating system 1000 may be configured such that (a) the fourth multichroic based redirecting optical element 524 may be configured in a light-receiving relationship with both the second light generating device 120 and the fifth light generating device 150, (b) the fourth multichroic based redirecting optical element 524 may be configured to receive the second device light 121 and fifth device light 151 and to direct the second device light 121 and fifth device light 151 in an optical path to the diffuser arrangement 7000 via the first multichroic based redirecting optical element 521.

[0355] Furthermore, in embodiments, the second multichroic based redirecting optical element 522 may be reflective for luminescent material light 201 and transmissive for diffused device light 701 (or transmissive for luminescent material light 201 and reflective for diffused device light 701). Further, in embodiments, the diffused device light 701 may comprise contributions of the second device light 121 and the fifth device light 151.

[0356] In specific embodiments, one of the second device light 121 and the fifth device light 151 may have a peak wavelength selected from the wavelength range of 430-490 nm, and the other one of the second device light 121 and the fifth device light 151 may have a peak wavelength selected from the wavelength range of 590-780 nm.

[0357] Referring to Fig. 6, in further embodiments, the diffuser arrangement 7000 may be configured as colinear arrangement, though a transmissive or non-colinear arrangement may also be possible. Referring to Fig. 6, in further embodiments, the light generating system 1000 (further) may comprise the third light generating device 130. Especially, optionally, the light generating system 1000 (further) may comprise the fourth light generating device 140. 2024PF80240

[0358] 79

[0359] Further, in specific embodiments, the luminescent material 200 may be selected to provide luminescent material light 201 having spectral power within the wavelength range of 490-590 nm (especially having a centroid wavelength (XLc) smaller than a peak wavelength of the second device light 121 within the second wavelength range of SOO- SO nm).

[0360] Further, referring to Fig. 6, and other figures, the fourth multichroic based redirecting optical element 524, may receive from two orthogonal branches device light, which may also be interchanged. Likewise, this may apply to the third multichroic based redirecting optical element 523 , and / or the second multichroic based redirecting optical element 522 and / or the first multichroic based redirecting optical element 521. Further, similarly, this may apply to the branches of the first polarization based redirecting optical element 511 and / or the branches of the second polarization based redirecting optical element 521.

[0361] In embodiments, the first light generating device 110 may comprise a first laser bank comprising a plurality of first lasers 10. Further, in embodiments, the second light generating device 120 may comprise a second laser bank comprising a plurality of second lasers 20. Likewise, this may in embodiments apply to one or more of the other type of light generating devices.

[0362] Further, in embodiments, in the first operational mode of the light generating system 1000 the system light 1001 may be white light having a correlated color temperature selected from the range of 2700-10000 K and a color rendering index of at least 65.

[0363] Yet, in further embodiments, the luminescent material 200 may be configured (i) in thermal contact with a thermally conductive material and / or (ii) onto a rotating element. Especially, the luminescent material 200 at least may comprise a luminescent material of the type AsBsOn Ce. Furthermore, in embodiments, A may comprise one or more of Y, La, Gd, Tb and Lu. Moreover, in embodiments, B may comprise one or more of Al, Ga, In and Sc.

[0364] Figs. 1-6 schematically depict embodiments of the light generating system 1000. However, each of the schematical drawings may include a combination of variants, which are not necessarily coupled (see further also below). Examples are swapping of branches of a multichroic based redirecting optical element or a polarization based redirecting optical element, the use of single color or bi-color second light generating devices, the use of a colinear diffuser arrangement or a non-colinear diffuser arrangement, or a transmissive diffuser arrangement, the use of a fourth light generating device but not third light generating device, the use of a fifth light generating device and not a third light 2024PF80240

[0365] 80 generating device, the use of a rotational element for supporting one or more of the diffuser and the luminescent material, the use of the polarization control system (or not), the use of rotation of a light generating device or the use of rotation of a birefringent element for controlling the polarization, the polarization control of device light of not only the first light generating device, but also of the third light generating device and / or the fourth light generating device, etc. etc.

[0366] Fig. 7 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. 7 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. 7 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall.

[0367] Fig. 7 also schematically depicts an embodiments of an outdoor light, or stage light, or stadium light. Fig. 7 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.

[0368] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and / or” 2024PF80240

[0369] 81 especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species". Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0370] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0371] 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.

[0372] 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.

[0373] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0374] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein. 2024PF80240

[0375] 82

[0376] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

[0377] The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and / or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and / or shown in the attached drawings.

[0378] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

2024PF8024083CLAIMS:

1. A light generating system (1000) comprising light generating devices (100), a luminescent material arrangement (2000), a diffuser arrangement (7000), optics (500), a control system (300), and a light exit (1090); wherein: the light generating devices (100) comprise (i) a first light generating device (110) configured to generate first device light (111), (ii) a second light generating device(120) configured to generate second device light (121) and a third light generating device (130) configured to generate third device light (131); wherein the first light generating device (110), the second light generating device (120), and the third light generating device (130) comprise one or more of a laser diode, a superluminescent diode, and a stacked multijunction light-emitting diode; the luminescent material arrangement (2000) comprises a luminescent material (200) configured to convert at least part of first device light (111) received by the luminescent material (200) into luminescent material light (201); the diffuser arrangement (7000) comprises a diffuser (700) configured to diffuse second device light (121) and first device light (111) received by the diffuser (700) into diffused device light (701); wherein incoming light, comprising second device light(121) and optional first device light (111) and / or third device light (131), on the diffuser (700), has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser (700), and wherein outgoing diffused device light (701) has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser (700), wherein the optical axes (Oi,Oo) have a mutual angle (P) unequal to 0°; the optics (500) comprise a first polarization based redirecting optical element (511) configured downstream of the first light generating device (110) and the third light generating device (130), and upstream of both the luminescent material arrangement (2000) and the diffuser arrangement (7000); wherein the light generating system (1000) is configured such that the first device light (111) and the third device light (131) received by the first polarization based redirecting optical element (511) comprise linear polarized light; wherein the first polarization based redirecting optical element (511) is configured to direct first device light (111) in dependence of its polarization to one or more of the luminescent2024PF8024084 material arrangement (2000) and the diffuser arrangement (7000), wherein the first polarization based redirecting optical element (511) is configured to direct at least part of the third device light (131) in an optical path to the luminescent material arrangement (2000); the optics (500) comprise a first multichroic based redirecting optical element (521) configured (a) in an optical path between the first polarization based redirecting optical element (511) and the diffuser arrangement (7000) and (b) in an optical path between the second light generating device (120) and the diffuser arrangement (7000); wherein the first multichroic based redirecting optical element (521) is configured to direct (i) first device light (111) and third device light (131) received via the first polarization based redirecting optical element (511), and (ii) second device light (121) received from the second light generating device (120) in an optical path to the diffuser arrangement (7000); the optics (500) comprise a second multichroic based redirecting optical element (522) configured (a) in an optical path between the first polarization based redirecting optical element (511) and the luminescent material arrangement (2000), (b) in an optical path between the luminescent material arrangement (2000) and the light exit (1090), and (c) in an optical path between the diffuser arrangement (7000) and the light exit (1090); wherein the second multichroic based redirecting optical element (522) is configured to direct (i) luminescent material light (201), received by the second multichroic based redirecting optical element (522), and (ii) diffused device light (701), received by the second multichroic based redirecting optical element (522), in an optical path to the light exit (1090); and the light generating system (1000) is configured to provide, via the light exit (1090), system light (1001); wherein the control system (300) is configured to control the system light (1001); wherein the system light (1001) in a first operational mode of the light generating system (1000) comprises at least part of the luminescent material light (201) and at least part of the diffused device light (701), and has a correlated color temperature selected from the range of 1800-12000 K and a CRI selected from the range of at least 65.

2. The light generating system (1000) according to claim 1, wherein the light generating system (1000) further comprises a polarization control system (600); wherein: the polarization control system (600) is configured to control a polarization of the first device light (111) reaching the first polarization based redirecting optical element (511), thereby controlling a power distribution of the first device light (111) over the optical paths to the luminescent material arrangement (2000) and the diffuser arrangement (7000);2024PF8024085 the polarization control system (600) comprises one or more of: (a) a birefringent rotator (610) configured downstream of the first light generating device (110) and upstream of the first polarization based redirecting optical element (511), wherein the polarization control system (600) is configured to control rotation of the birefringent rotator (610); and wherein the birefringent rotator (610) comprises a X / 2 waveplate; and (b) an actuator (630) configured to rotate the first light generating device (110), wherein the polarization control system (600) is configured to control the actuator (630); and the control system (300) is configured to control a spectral power distribution of the system light (1001) by controlling one or more of (i) the polarization control system (600) and (ii) one or more of the light generating devices (100).

3. The light generating system (1000) according to any one of the preceding claims 1-2, wherein the optics (500) comprises a second polarization based redirecting optical element (512); and wherein: the diffuser arrangement (7000) is configured as colinear arrangement, wherein incoming second device light (121), received by the diffuser arrangement (7000), and incoming first device light (111), received by the diffuser arrangement (7000), propagate over at least part of its optical path colinear with an optical path of the diffused device light (701) propagating from the diffuser arrangement (7000) to the light exit (1090); the diffuser (700) comprises a polarization maintaining diffuser; wherein the diffuser arrangement (7000) further comprises a X / 4 waveplate (710) configured between the second polarization based redirecting optical element (512) and the diffuser (700), wherein the second polarization based redirecting optical element (512) is configured to direct second device light (121), received by the second polarization based redirecting optical element (512), and first device light (111), received by the second polarization based redirecting optical element (512), to the X / 4 waveplate (710), wherein the X / 4 waveplate (710) is configured to convert linear polarized light received by the X / 4 waveplate (710) into elliptical polarized light and to convert elliptical polarized light received by the X / 4 waveplate (710) into linear polarized light; the second polarization based redirecting optical element (512) is configured (a) in an optical path between the first multi chroic based redirecting optical element (521) and the diffuser arrangement (7000), and (b) in an optical path between the diffuser arrangement (7000) and the second multichroic based redirecting optical element (522); wherein the second polarization based redirecting optical element (512) is configured to (i)2024PF8024086 direct second device light (121), received by the second polarization based redirecting optical element (512), and first device light (111), received by the second polarization based redirecting optical element (512), to the diffuser arrangement (7000), and (ii) direct diffused device light (701) received from the diffuser arrangement (7000) in an optical path to the second multichroic based redirecting optical element (522); and wherein the light generating system (1000) is configured such that the second device light (121) received by the second polarization based redirecting optical element (512) comprises linear polarized light.

4. The light generating system (1000) according to claim 3, wherein incoming light, comprising second device light (121) and optional first device light (111) and / or third device light (131), on the diffuser (700), has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser (700) equal to 0°, wherein outgoing diffused device light has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser (700) equal to 180°, wherein the optical axes (Oi,Oo) may have a mutual angle (P) equal to 180° such that the optical axes (Oi,Oo) are anti -parallel.

5. The light generating system (1000) according to any one of the preceding claims 1-2, wherein the diffuser arrangement (7000) is configured as non-colinear arrangement; wherein the light generating system (1000) is configured such that incoming light, comprising second device light (121) and optional first device light (111), on the diffuser (700), has an optical axis (Oi) having a first angle (ai) with a normal to the diffuser (700) unequal to 0°, and wherein outgoing diffused device light (701) has an optical axis (Oo), having a second angle (ao) relative to the normal to the diffuser (700) unequal to 0°, wherein the optical axes (Oi,Oo) have a mutual angle (P) unequal to 0°.

6. The light generating system (1000) according to any one of the preceding claims, wherein the first device light (111) and the second device light (121) have different spectral power distributions; wherein the first device light (111) has a first peak wavelength (kpl) selected from the wavelength range of 430-490 nm, wherein the second device light (121) has a second peak wavelength (Zp2) selected from the wavelength range of 380-780 nm, wherein the third device light (131) has a third peak wavelength (Zp3) selected from the wavelength range of 430-490 nm, wherein |Xpl-Xp2| > 10 nm, and wherein |Xp3- pl| < 20 nm.2024PF80240877. The light generating system (1000) according to any one of the preceding claims, wherein the first polarization based redirecting optical element (511) comprises a polarizing beam splitter or a partial polarizing beam splitter, wherein for the first polarization based redirecting optical element (511) one of the following applies: (a) the first polarization based redirecting optical element (511) is fully reflective for s-polarized blue device light and fully transmissive for p-polarized blue device light; or (b) the first polarization based redirecting optical element (511) is fully transmissive for p-polarized blue device light and partly transmissive for s-polarized blue device light; or (c) the first polarization based redirecting optical element (511); is fully reflective for s-polarized blue device light and partly transmissive for p-polarized blue device light; or (d) the first polarization based redirecting optical element (511) is partly reflective and partly transmissive for both s- polarized and p-polarized blue device light; wherein the polarization is referenced to a splitting plane of the polarizing beam splitter or the partial polarizing beam splitter, wherein the splitting plane is a plane at which the polarization based beam splitting takes place.

8. The light generating system (1000) according to any one of the preceding claims, wherein: the second device light (121) has a second peak wavelength (Zp2) selected from the wavelength range of 590-780 nm; the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) white system light (1000) comprising luminescent material light (201) and diffused device light (701), wherein the diffused device light (701) comprises contributions from the first device light (111) and the second device light (121); and the control system (300), as defined in claim 2, is configured to control the spectral power distribution of the system light (1001) by controlling one or more of (a) a rotation of the birefringent rotator (610) and (b) one or more of the first light generating device (110), the second light generating device (120), and the third light generating device (130).

9. The light generating system (1000) according to any one of the preceding claims 7-8, wherein:2024PF8024088 the second light generating device (120) is configured to generate primary second device light (121a) having spectral power in a first wavelength range of 430-490 nm and secondary second device light (121b) having spectral power in a second wavelength range of 590-780 nm; the second multichroic based redirecting optical element (522) is transmissive for luminescent material light (201) and reflective for diffused device light (701); in an operational mode of the light generating system (1000), the diffused device light (701) comprises contributions of the primary second device light (121a) and the secondary second device light (121b); and the luminescent material (200) is selected to provide luminescent material light (201) having spectral power within the wavelength range of 490-590 nm.

10. The light generating system (1000) according to any one of the preceding claims 7-9, wherein: the diffuser arrangement (7000) is configured as non-colinear arrangement as defined in claim 4; and the polarization control system (600) comprises the birefringent rotator (610) as defined in claim 2.

11. The light generating system (1000) according to any one of the preceding claims, further comprising a fourth light generating device (140) and a third multichroic based redirecting optical element (523); wherein: the fourth light generating device (140) is configured to generate fourth device light (141); the fourth light generating device (140) comprises one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode; the light generating system (1000) is configured such that (a) the first polarization based redirecting optical element (511) is configured in a light-receiving relationship with the fourth light generating device (140), (b) the fourth device light (141) received by the first polarization based redirecting optical element (511) comprises linear polarized light, and (c) the third multichroic based redirecting optical element (523) is configured (i) downstream the fourth light generating device (140) and (ii) upstream of the first polarization based redirecting optical element (511);2024PF8024089 the third multichroic based redirecting optical element (523) is configured to receive fourth device light (141) and to direct fourth device light (141) to the first polarization based redirecting optical element (511); and the first polarization based redirecting optical element (511) is configured to direct at least part of the fourth device light (141) received by the first polarization based redirecting optical element (511) in an optical path to the luminescent material arrangement (2000).

12. The light generating system (1000) according to any one of the preceding claims, further comprising a rotational element (1250), a rotator (1240), and an out of plane mirror (M3); wherein: wherein the rotational element (1250) is configured to support the luminescent material (200) and the diffuser (700); and wherein the rotator (1240) is configured to rotate the rotational element (1250) during an operational mode of the light generating system (1000); and the out of plane mirror (M3) is configured downstream of the second multichroic based redirecting optical element (522) and upstream of the light exit (1090); wherein the out of plane mirror (M3) is configured to direct light received by the out of plane mirror (M3) in a direction having an angle unequal to zero with a plane wherein the optical paths between (a) the first polarization based redirecting optical element (511) and the first multichroic based redirecting optical element (521) and (b) the first multichroic based redirecting optical element (521) and the second multichroic based redirecting optical element (522) are configured.

13. The light generating system (1000) according to any one of the preceding claims, further comprising a fifth light generating device (150) and a fourth multichroic based redirecting optical element (524), wherein: the fifth light generating device (150) is configured to generate fifth device light (151); the fifth device light (151) has a fifth peak wavelength (Zp5) selected from the wavelength range of 430-780 nm; the second device light (121) has a second peak wavelength (Zp2) selected from the wavelength range of 380-780 nm as defined in claim 5; wherein |Xp5-Xp2| > 10 nm;2024PF8024090 the fifth light generating device (150) comprises one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode; the light generating system (1000) is configured such that (a) the fourth multichroic based redirecting optical element (524) is configured in a light-receiving relationship with both the second light generating device (120) and the fifth light generating device (150), (b) the fourth multichroic based redirecting optical element (524) is configured to receive the second device light (121) and fifth device light (151) and to direct the second device light (121) and fifth device light (151) in an optical path to the diffuser arrangement (7000) via the first multichroic based redirecting optical element (521); and the second multichroic based redirecting optical element (522) is reflective for luminescent material light (201) and transmissive for diffused device light (701) or transmissive for luminescent material light (201) and reflective for diffused device light (701), wherein the diffused device light (701) comprises contributions of the second device light (121) and the fifth device light (151).

14. The light generating system (1000) according to any one of the preceding claims, wherein: the first light generating device (110) comprises a first laser bank comprising a plurality of first lasers (10), and wherein the second light generating device (120) comprises a second laser bank comprising a plurality of second lasers (20); one or more of the light generating devices (100) comprises a semiconductor laser selected from the group of GaN, AlGaN, InGaN, AlGalnN, GaP, InP, GalnP, and AlGalnP lasers; in the first operational mode of the light generating system (1000) the system light (1001) is white light having a correlated color temperature selected from the range of 2700-10000 K and a color rendering index of at least 65; the luminescent material (200) is configured (i) in thermal contact with a thermally conductive material and / or (ii) onto a rotating element; and the luminescent material (200) at least comprises a luminescent material of the type AsBsOn Ce, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc.

15. A lighting device (1200) selected from the group of a lamp (1), a luminaire (2), a vehicle light, a projector device (3), a lighting fixture, and an automotive lighting2024PF8024091 device, comprising the light generating system (1000) according to any one of the preceding claims.

Images