Compact and efficient non-coaxial reflective channel for a laser-phosphor white light engine

Abstract

The invention provides a light generating system (1000) comprising a first light generating device (110), a second light generating device (120), a luminescent material (200), a diffuser assembly (1700), optics (500), and a light exit (1090), wherein: (A) the first light generating device (110) is configured to generate first device light (111), and the second light generating device (120) is configured to generate second device light (121); (B) the luminescent material (200) is configured to convert at least part of second device light (121) into luminescent material light (201); (C) the diffuser assembly (1700) comprises a diffuser (710), a condenser optical element (730), and a collecting optical element (740); (D) the condenser optical element (730) is configured to provide a focused beam (731) comprising first device light (111) in an optical path to the diffuser (710); (E) the diffuser (710) is configured to provide a diffused beam (711) comprising first device light (111) in an optical path to the collecting optical element (740), wherein an optical axis (Oi) of the focused beam (731) comprising first device light (111) and an optical axis (OR) of the diffused beam (711) comprising first device light (111) have a mutual angle (β), wherein the mutual angle (β) is selected from the range of 80°≤β≤140°; (F) the collecting optical element (740) is configured in a light-receiving relationship with the diffuser (710); wherein the collecting optical element (740) is configured to provide a collimated diffused beam (741) comprising first device light (111) in an optical path to the light exit (1090); (G) the optics (500) comprise one or more redirection optical elements (505) configured to direct one or more of: (i) the first device light (111) in an optical path to the diffuser assembly (1700), (ii) the collimated diffused beam (741) comprising first device light (111) in an optical path to the light exit (1090), (iii) the second device light (121) in an optical path to the luminescent material (200), and (iv) the luminescent material light (201) in an optical path to the light exit (1090); and (H) the light generating system (1000) is configured to generate in a first operational mode of the light generating system (1000) system light (1001) comprising at least part of the collimated diffused beam (741) comprising first device light (111) and at least part of the luminescent material light.

Description

[0001] COMPACT AND EFFICIENT NON-COAXIAL REFLECTIVE CHANNEL FOR A

[0002] LASER-PHOSPHOR WHITE LIGHT ENGINE

[0003] FIELD OF THE INVENTION

[0004] The invention relates to a light generating system. The invention further relates to a lighting device comprising the light generating system.

[0005] BACKGROUND OF THE INVENTION

[0006] Lighting fixtures comprising laser diffusion optics are known in the art. US20160223895A1, for instance, describes a light source apparatus and a projection display apparatus including: a laser light source; and a multiplexing reflection mirror having a first surface on which a partial reflection coating having a predetermined reflectance is formed, and a second surface on which a total reflection coating is formed, the first surface and the second surface being opposite to each other and formed in a parallel flat shape. The multiplexing reflection mirror is disposed so as to incline toward an optical path of an emission light from the laser light source such that the emission light is incident from first surface.

[0007] SUMMARY OF THE INVENTION

[0008] Laser sources are finding more applications in lighting where a high brightness light source is desired, such as e.g. automotive headlights, projection applications, cinema lighting, and entertainment lighting such as stage lighting. When lasers are used to convert part of their power into another spectral range by means of light converting material (phosphor), a broader spectrum of a light source is created, providing color rendering quality sufficient for multiple general lighting applications, while still maintaining relatively high brightness. In general, transmissive or reflective architectures may be used for light conversion, the latter providing more intrinsic eye-safety with relation to the possibility of exposure to direct laser radiation in case of malfunctioning of the optical component. In this case it is generally also required that the spatial beam profiles (and optionally also the angular intensity distributions) of the converted and blue laser beams are matching each other to result in a color-uniform output beam. Often the incoming and reflected beams may propagate collinearly in opposite directions, and thus may need to be separated from each other. Such separation can be achieved by altering the polarization state of the incoming and outgoing beams. This involves a number of optical components, which result in lowering the system efficiency and making the architecture more complex, bulky and expensive. Additionally, with high powers and high power density of the lasers, even a small fraction of light absorbed in the lens material may introduce local heating, expansion and stresses in the lens, which may scramble the polarization state of the laser beam, therefore resulting in additional uncontrolled light losses.

[0009] For transmissive architectures typically additional electronic / sensor measures may need to be added to make the architecture eye-safe, however, such measures also make the system more complex and costly.

[0010] 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.

[0011] According to a first aspect, the invention provides a light generating system (“system”) comprising one or more light generating devices, a luminescent material, a (first) diffuser assembly, optics, and a light exit. In embodiments, the one or more light generating devices may be configured to generate first device light. Therefore, in embodiments, the first light generating device may comprise a first solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. In further embodiments, the diffuser assembly may comprise a (small angle, reflective) diffuser, a (transmissive) condenser optical element, and a (transmissive) collecting optical element. Further, in embodiments, the condenser optical element may be configured to provide a focused beam comprising first device light in an optical path to the diffuser. Especially, the diffuser may be configured in a light-receiving relationship with the condenser optical element, the reflective diffuser may be configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element. Moreover, in embodiments, an optical axis (Oi) of the focused beam comprising first device light and an optical axis (OR) of the diffused beam comprising first device light may have a mutual angle (P). Furthermore, in embodiments, the mutual angle (P) may be selected from the range of 80°<p<140°. Especially, the collecting optical element may be configured in a light-receiving relationship with the diffuser. Further, in embodiments, the collecting optical element may be configured to provide a collimated diffused beam comprising first device light in an optical path to the light exit. Furthermore, in embodiments, the optics may comprise one or more redirection optical elements. In embodiments, the one or more redirection optical elements may be configured to direct the first device light in an optical path to the diffuser assembly. Additionally or alternatively, in embodiments, the one or more redirection optical elements may be configured to direct the collimated diffused beam comprising first device light in an optical path to the light exit. Further, in embodiments, the one or more light generating devices may be configured to generate second device light. Therefore, in embodiments, the second light generating device may comprise a second solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. Furthermore, in embodiments, the luminescent material may be configured to convert at least part of second device light received by the luminescent material into luminescent material light. Additionally or alternatively, in embodiments, the one or more redirection optical elements may be configured to direct the second device light in an optical path to the luminescent material. Additionally or alternatively, in embodiments, the one or more redirection optical elements may be configured to direct the luminescent material light in an optical path to the light exit. In further embodiments, the light generating system may be configured to generate in a first operational mode of the light generating system (white) system light comprising at least part of the collimated diffused beam comprising first device light and at least part of the (collimated) luminescent material light. Hence, in embodiments, the invention provides a light generating system comprising one or more light generating devices, a luminescent material, a diffuser assembly, optics, and a light exit, wherein: (A) the one or more light generating devices may be configured to generate first device light and second device light, wherein the one or more light generating devices may comprise one or more solid state light sources selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (C) the luminescent material may be configured to convert at least part of second device light received by the luminescent material into luminescent material light; (D) the diffuser assembly may comprise a (small angle reflective) diffuser, a (transmissive) condenser optical element, and a (transmissive) collecting optical element; (E) the condenser optical element may be configured to provide a focused beam comprising first device light in an optical path to the diffuser; (F) the diffuser may be configured in a light-receiving relationship with the condenser optical element; the diffuser may be configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element, wherein an optical axis (Oi) of the focused beam comprising first device light and an optical axis (OR) of the diffused beam comprising first device light may have a mutual angle (P), wherein the mutual angle (P) may be selected from the range of 80°<P<140°; (G) the collecting optical element may be configured in a light-receiving relationship with the diffuser; wherein the collecting optical element may be configured to provide a collimated diffused beam comprising first device light in an optical path to the light exit; (H) the optics may comprise one or more redirection optical elements configured to direct one or more of (i) the first device light in an optical path to the diffuser assembly, (ii) the collimated diffused beam comprising first device light in an optical path to the light exit, (iii) the second device light in an optical path to the luminescent material, and (iv) the luminescent material light in an optical path to the light exit; and (I) the light generating system may be configured to generate in a first operational mode of the light generating system (white) system light comprising at least part of the collimated diffused beam comprising first device light and at least part of the luminescent material light.

[0012] Such a light generating system may provide a significantly simplified reflective architecture for a blue channel of the (laser phosphor) white light engine. Compared to commonly used architectures of polarization-based separation of the incoming and reflected beams propagating co-axially in opposite directions, the current invention proposes an alternative architecture with non-coaxial re-direction of the incoming beam. The proposed design may eliminate the need for a highly-stressed small condenser lens, which would otherwise be a critical -to-performance component because of high laser power density and related light absorption and stresses in lens material. As such, the current invention may eliminate the need for expensive components, such as dichroic and / or polarizing beam splitters.

[0013] Furthermore, the use of the non-coaxial architecture enables use of separate lenses for condensing and collecting of the incoming and outgoing beams of light relative to the diffuser. Such separate lenses may provide the benefit of improved beam shaping (e.g. to match beams provided by luminescent materials), which may in turn result in good color uniformity of the output light.

[0014] Embodiments as described herein do not rely on separation of the incoming and outgoing beams (at the diffuser) based on polarization, and may thereby eliminate additional depolarization losses and requirements to components from the system. Thus, a compact, efficient, more robust, lower cost, and safe optical architecture is proposed. The invention may thus provide a compact and efficient non-coaxial reflective channel for a laser- phosphor white light engine. Furthermore, the light generating system may provide high brightness and color point tuneability.

[0015] The light generating system (or “system”) may thus comprise one or more light generating devices, a luminescent element, a (first) diffuser assembly, optics, and a light exit. Here below, embodiments of the different elements of the light generating system will be described in further detail. In particular, the light generating system will first be described comprising a (first) light generating device, a (first) diffuser assembly, and a light exit. Further below, an expanded light generating system further comprising a (second) light generating device, a luminescent element, and (further) optics will be described in further detail.

[0016] The light generating devices may be configured to generate device light. In embodiments, the light generating devices may each comprise a solid-state light source. In embodiments, the one or more light generating devices may comprise (at least) a first light generating device and a second light generating device (and optionally further light generating devices).

[0017] 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 solid state light source may be configured to generate first light source light. Especially, the first device light may essentially consist (especially at least 95%) of the first light source light. 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. The first device light may essentially consist (especially comprise at least 95%) of the (laser) light of the laser diodes.

[0018] A laser bank may comprise a relatively dense assembly of multiple laser diodes on a shared substrate provided with collimating optics, such as collimating lenses comprising one lens per laser diode (e.g. arranged in an array of lenses). Especially, a laser bank may comprise a light emitting arrangement comprising an (2D) array of a plurality of laser diodes arranged on a thermally conductive carrier and a (lens array having a) plurality of collimator lenses corresponding to the laser diodes such that each laser diode of the plurality of laser diodes comprises a collimator lens for collimating laser light emitted by the laser diode. The arrangement may comprise a package architecture or a canned architecture. In case of the package architecture a laser diode chip array is arranged on the thermally conductive carrier. A plurality of electrodes may be present for electrically connecting the plurality of laser diodes. The 2D array may e.g. comprise at least 8 laser diodes. The use of laser banks may especially be convenient for projecting a beam of high power laser light onto a luminescent converter without the need for using an inverse beam expander. Depending on the desired output beam characteristics, additional beam shaping optics may be needed. Laser banks may be used to boast the input power.

[0019] Note that an array of solid state light sources may provide multiple light generating devices, such as a first light generating device and a second light generating device. For instance, a subset of laser diodes of an array of laser diodes may be used as first light generating device, and its device light may at least partially follow another optical path than device light of another subset of laser diodes from that array (of laser diodes). Hence, in embodiments a single laser bank may be applied, of which the light is split in multiple portions, effectively providing multiple light generating devices. In general, this may imply the application of optics, allowing to divide the laser light of multiple subsets of lasers from the same bank into their respective (separate) beams of light that at least partially do not have identical optical paths (in the light generating system). The subsets may comprise one or more of the laser diodes of the laser bank. However, especially a single laser diode may only be comprised by a single subset. Notwithstanding such embodiments, of course also multiple laser banks may be used to provide multiple light generating devices.

[0020] In some embodiments, the one or more light generating devices may comprise a first light generating device (e.g. a first laser bank) and a discrete second light generating device (e.g. a second laser bank). In such embodiments, characteristics of the system light may be controllable through (i) individual control (or manipulation) of the (e.g. radiant flux) of the light generating devices, (ii) individual control (or manipulation) of light characteristics such as polarization of the device light generated by the respective light generating devices, and / or (iii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating devices, see also further below. Hence, such embodiments may provide controllability at the device, downstream of the device, and at the optics.

[0021] Additionally or alternatively, in some embodiments, the one or more light generating devices may comprise a (single) light generating device (e.g. a laser bank) comprising a multiple subsets of (solid state) light sources (e.g. a laser bank comprising a first subset of lasers and a second subset of lasers). In such embodiments, characteristics of the system light may be controllable through (i) individual control (or manipulation) of the (e.g. radiant flux) of the subsets of (solid state) light sources in the light generating device, (ii) individual control (or manipulation) of light characteristics such as polarization of the device light generated by the respective subsets of (solid state) light sources in the light generating device, and / or (iii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating device, see also further below. Hence, such embodiments may provide controllability at the device, downstream of the device, and at the optics.

[0022] Yet additionally or alternatively, in some embodiments, the one or more light generating devices may comprise a single light generating device (e.g. a laser bank). In such embodiments, characteristics of the system light may be controllable through (i) control (or manipulation) of light characteristics such as polarization of the device light generated by the light generating device, and / or (ii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating device, see also further below. Hence, such embodiments may provide controllability downstream of the device and at the optics.

[0023] Further, in embodiments, the first light generating device may especially be configured to generate first device light having a first peak wavelength (Xpi). In embodiments, the first device light may essentially be any color light, such as e.g. blue light, red light, or a combination of different colors (e.g. white light). Especially, in embodiments, the first device light may have a first peak wavelength (Xpi) selected from the visible wavelength range, i.e., light having one or more wavelengths in the range of about 380-780 nm. In specific embodiments, the first device light may have a first peak wavelength (Xpi) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. More especially, in embodiments, the first device light may have a first peak wavelength (Xpi) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, the first device light may be blue light.

[0024] The terms “blue light” or “blue emission”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues). However, intensity at shorter wavelengths may also be possible, such as within the wavelength range of 400-440 nm. Especially, in embodiments the device light has a peak wavelength selected from the blue wavelength range.

[0025] Yet further, in embodiments, the first device light may have a first optical axis (Oi). Herein, the term “optical axis” (O) may be defined as an imaginary line that defines the path along which light propagates towards or from a respective element. For example, the first optical axis (Oi) may be defined as an imaginary line that defines the path along which light propagates from the first light generating device. More especially, the optical axis (O) may coincide with the direction of the light with the highest radiant flux. The first light generating device may be configured to generate first device light having a first average beam cross-sectional diameter defined by its full width half maximum (FWHM) and defined in a plane perpendicular to the first optical axis (Oi). In embodiments, the first average beam cross-sectional diameter may be selected from the range of 3-50 mm, like from the range of 4-50 mm, such as from the range of 10-40 mm, like from the range of 20-30 mm. Especially, in embodiments, the first average beam cross-sectional diameter may be selected from the range of 10-50 mm. Note that, in embodiments, the beam cross-section (defined in a plane perpendicular to the first optical axis (Oi)) may have essentially any two-dimensional shape, such as e.g. a square shape, a rectangular shape, a circular shape, or a hexagonal shape. Therefore, the beam cross-sectional diameter may be defined as an average beam cross- sectional diameter. Alternatively, in embodiments, a beam cross-sectional diameter may herein be defined as an equivalent circular diameter. The equivalent circular diameter (or ECD) (or “circular equivalent diameter”) of an (irregularly shaped) two-dimensional shape is the diameter of a circle of equivalent area. For instance, the equivalent circular diameter of a square with side a is 2*a*SQRT(l / 7t). For a circle, the diameter is the same as the equivalent circular diameter. Would a circle in an xy-plane with a diameter D be distorted to any other shape (in the xy-plane), without changing the area size, then the equivalent circular diameter of that shape would be D.

[0026] The first light generating device may especially be configured to provide first device light to the diffuser assembly. In embodiments, the diffuser assembly may comprise a diffuser and one or more optical elements, such as e.g. one or more lenses. In specific embodiments, the diffuser assembly may comprise (at least) a (reflective) diffuser, a condenser optical element, and a collecting optical element. Embodiments wherein the diffuser assembly comprises further (optical) elements are herein not excluded. Especially, in embodiment, the diffuser assembly may comprise a reflective diffuser. Additionally or alternatively, in embodiments, the diffuser assembly may comprise a (partially) transmissive diffuser combined with a reflective optical component configured behind (relative to a plane of incidence of) the transmissive diffuser. In such embodiments, the reflective optical component may e.g. comprise a (specular) mirror coating configured on the diffuser and / or a discrete specular mirror configured externally (and not in optical contact) of the diffuser, see also further below.

[0027] In embodiments, the condenser optical element may be configured in an optical path between the first light generating device and the diffuser. As such, in embodiments, the condenser optical element may be configured in a light-receiving relationship with the first light generating device. In other words, the condenser optical element may be configured downstream of the first light generating device.

[0028] 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”.

[0029] The condenser optical element may especially be configured to receive first device light (originating from the first light generating device) and propagate the first device light in an optical path to the diffuser. Therefore, in embodiments, the condenser optical element may be transmissive for (at least) the first device light. Especially, in embodiments, the condenser optical element may be configured to condense or focus the first device light received by the condenser optical element. The condenser optical element may thus, in embodiments, be configured to provide a focused (or convergent) beam comprising first device light in an optical path to the diffuser.

[0030] The condenser optical element may, in embodiments, comprise a lens. Especially, in embodiments, the condenser optical element may comprise a surface configured to condense an incoming parallel beam of light, such as a lens surface. In embodiments, the condenser optical element may for example comprise one or a curved lens surface, a Fresnel-type lens surface, and a metasurface (i.e., a flat textured surface). Especially, in embodiments, the condenser optical element may comprise an aspherical lens. However, in alternative embodiments (in dependence on desired requirements for the out-put system light), the condenser optical element may also comprise a spherical lens. In embodiments, the condenser optical element may comprise a lens with an optical diameter selected from the range of 15-60 mm, such as from the range of 20-50 mm, like from the range of 25-40 mm. Such embodiments may provide the benefit that the diameter of the condenser optical element may be large enough to accommodate an incoming beam of (first) device light from the (first) light generating device, while not being too bulky so that it may still fit in the light generating system.

[0031] Furthermore, in embodiments, the condenser optical element may comprise a material having low absorption for (at least) the spectral range of the first device light. Especially, in embodiments, the condenser optical element may comprise a material having an absorption coefficient selected from the range of <0.01 cm'1for (at least) the first peak wavelength (Xpi), i.e., for (at least) the spectral range of the first device light. More especially, in embodiments, the condenser optical element may comprise a material having an absorption coefficient selected from the range of <0.005 cm'1for (at least) the first peak wavelength (Xpi). The condenser optical element may for example comprise one or more materials selected from the group comprising: a glass, a polymeric material, and a ceramic material. In specific embodiments, the condenser optical element comprises a glass material having an absorption coefficient selected from the range of <0.01 cm'1for (at least) the first peak wavelength (Xpi).

[0032] The condenser optical element may thus be configured to provide a focused beam comprising first device light in an optical path to the diffuser. Hence, in embodiments, the diffuser may be configured in a light-receiving relationship with the condenser optical element. In other words, the diffuser may be configured downstream of the condenser optical element. The condenser optical element may especially be configured to provide a spot of first device light onto the diffuser. In embodiments, the spot of first device light may have a spot size defined as an area comprising at least 90% of the intensity of the first device light incident on the diffuser. In embodiments, the spot size may be at most 100% of a cross- sectional area of a reflective surface of the diffuser (assembly), such as at most 90%, like at most 80%.

[0033] The reflective diffuser may especially be configured to receive (the focused beam comprising) first device light (originating from the condenser optical element) and reflect the first device light in an optical path to the collecting optical element. Therefore, in embodiments, the diffuser (assembly) may be reflective for (at least) the first device light. Especially, in embodiments, the diffuser (assembly) may be configured to diffuse and reflect the (focused beam of) first device light received by the diffuser. The diffuser may thus, in embodiments, be configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element. The focused beam comprising the first device light (provided by the condenser optical element) may have an optical axis relative to the diffuser. Especially, in embodiments, relative to the diffuser the incident focused beam comprising the first device light may have an (incident) optical axis (Oi). Hence, in embodiments, the (incident) optical axis (Oi) may comprise an optical axis of light incident on the diffuser. Conversely, in embodiments, the diffused beam comprising the first device light (provided by the diffuser) may have an optical axis relative to the diffuser. Especially, relative to the diffuser the reflected diffused beam comprising the first device light may have an (reflection) optical axis (OR). Hence, in embodiments, the (reflection) optical axis (OR) may comprise an optical axis of light reflected from the diffuser (assembly). In embodiments, the (incident) optical axis (Oi) and the (reflection) optical axis (OR) may have a mutual angle (P). Especially, in embodiments, the mutual angle (P) may be selected from the range of 70°<p<150°, such as from the range of 80°<P<140°, like from the range of 80°<P<l 10°, especially from the range of 85°<P<100°. In embodiments, the (incident) optical axis (Oi) of the incident focused beam comprising the first device light may correspond to an average angle of incidence of the first device light on (a plane of incidence of) the diffuser. Conversely, the (reflection) optical axis (OR) of the reflected diffused beam comprising the first device light may correspond to an average angle of reflectance of the first device light from (a plane of incidence of) the diffuser. Especially, in embodiments, average angles of incidence and / or reflection may be defined in an incidence plane of the diffuser with relation to the normal of said incidence plane. In specific embodiments, the average angle of incidence (of the first device light on the diffuser) and the average angle of reflection (of the first device light from the diffuser) may be symmetrical around the normal of the plane of incidence. Hence, in such embodiments, the average angles of incidence and reflection may be derived from the value of the mutual angle (P).

[0034] Hence, in embodiments, the diffuser may be configured in a non-collinear (or non-coaxial) configuration, i.e., the incoming beam of light and the outgoing beam of light may not be collinear. In specific embodiments, the mutual angle (P) may be 90°, i.e., the (incident) focused beam comprising the first device light may be essentially perpendicular to the (reflection) diffused beam comprising the first device light. However, a mutual angle (P) of exactly 90° may not be necessary. A smaller or larger mutual angle (P) may be provided in view of the desired architecture or design of the system. In embodiments, the mutual angle (P) may be at least 75°, such as at least 85°. Such embodiments may be beneficial as such a mutual angle (P) allows for the configuration of the condensing optical element and the collecting optical element at (about) their respective focal distances from the reflective diffuser as measured respectively on the incident optical axis and the reflection optical axis. In case of a smaller mutual angle (P), the condensing and collecting optical elements may be limited in size due to the available space, which may lead to a loss of light. In case of larger angles, the condensing and collecting optical elements may be less (or even not at all) limited in size.

[0035] The diffuser may, in embodiments, thus be configured to diffuse (or scatter) (at least the first) device light received by the diffuser. Especially, in such embodiments, the diffuser may comprise a reflective diffuser. Alternatively, in embodiments, the diffuser may comprise a transmissive diffuser combined with a (specular) reflective optical component configured behind (relative to a plane of incidence of) the transmissive diffuser. For example, the transmissive diffuser may comprise optical micro-structures configured to provide (both) transmissive and reflective diffusion of light received by the diffuser. In such embodiments, the reflective optical component may be configured to reflect transmi ssively diffused light that may otherwise be lost. Therefore, the reflective optical component may e.g. comprise a (specular) mirror coating configured on the diffuser and / or a discrete specular mirror configured externally (and not in optical contact) of the diffuser. Hence, in such embodiments, the diffuser may comprise a combination of optical micro-structures with a specular reflective element(s).

[0036] Especially, in embodiments, the diffuser may be (diffuse) reflective for (at least first) device light. In embodiments, the diffuser may comprise a surface diffuser, a volume diffuser, or a combination of a surface and volume diffuser. The diffuser may, in embodiments, comprise one or more materials selected from the group comprising: a glass with high transmission in the spectral range of the (first and second) device light, a silicone- based material, and a transparent ceramic material such as e.g. sapphire. Especially, in embodiments, the diffuser may comprise one (or more) of: a small angle scattering metallic substrate, a white ceramic reflector, a patterned glass-based substrate with a (deposited metallic) reflective coating, a combination of optical micro-structures with specular reflective elements , a combination of a solid optical body with a diffuse reflector, a combination of a structured surface with a dichroic or thin film deposited reflector, and a combination of a total internal reflector element with additional surface structuring. The diffuser may especially be selected based on preferred system characteristics, such as thermal management, bulkiness, and cost.

[0037] In specific embodiments, the diffuser may comprise a small angle diffuser. Especially, in some embodiments, the diffuser (comprising the small angle diffuser) may be configured to provide an angular spread of diffusion where as a function of a scatter angle 0, the intensity 1(9) of the diffused (or scattered) light may correspond to a function of cosn(9), wherein n may be selected from the range of 10-100, like from the range of 20-100, such as from the range of 30-90. However, in other embodiments (when the diffuser comprises e.g. a top-hat diffuser), the diffuser (comprising the small angle diffuser) may be configured to provide an angular spread of diffusion corresponding to one or more of a top-hat diffusion, or another engineered diffusion. In other words, in embodiments, the diffuser may (comprise a small angle diffuser that may) be configured to re-distribute incoming first device light such that first device light, propagating from the diffuser to the collecting optical element (i.e. the diffused beam (comprising first device light)), may have a full width at half maximum (FWHM) selected from the range of 5-60°, such as from the range of 10-50°, like from the range of 10-40°, especially from the range of 12-30°. In the embodiments described here, the FWHM may especially refer to the diffused beam (comprising first device light) and therefore may be the result of both the divergence of the incident beam and the diffusion by the diffuser assembly.

[0038] The diffuser may thus be configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element. Hence, in embodiments, the collecting optical element may be configured in a light-receiving relationship with the diffuser. In other words, the collecting optical element may be configured downstream of the diffuser. The collecting optical element may especially be configured to receive (or collect) (the diffused beam comprising) first device light (originating from the diffuser). In embodiments, the collecting optical element may be configured to collimate the received first device light to provide a collimated diffused beam comprising first device light in an optical path to the light exit. Note that, in embodiments, the collimated diffused beam comprising first device light may propagate via one or more further (optical) elements configured in the optical path between the collecting optical element and the light exit.

[0039] In embodiments, the collecting optical element may thus be transmissive for (at least) the first device light. The collecting optical element may further, in embodiments, be transparent for (at least) the first device light. Especially, in embodiments, the collecting optical element may be configured to collect and collimate the (diffused beam of) first device light received by the collecting optical element. The collecting optical element may thus, in embodiments, be configured to provide a collimated diffused beam comprising first device light in an optical path to the light exit. The collecting optical element may, in embodiments, comprise a lens. Especially, in embodiments, the collecting optical element may comprise an aspherical lens. However, in alternative embodiments (in dependence on desired requirements for the out-put system light), the collecting optical element may also comprise a spherical lens. In embodiments, the collecting optical element may comprise a lens with an optical diameter selected from the range of 15-60 mm, such as from the range of 20-50 mm, like from the range of 25-40 mm. Such embodiments may provide the benefit that the diameter of the collecting optical element may be large enough to accommodate an incoming diffused beam comprising (first) device light propagating from the diffuser (to the collecting optical element), while not being too bulky so that it may still fit in the light generating system.

[0040] Note that, in embodiments, the condensing optical element and the collecting optical element may comprise essentially the same type of optical element. However, this may not necessarily be the case. In some embodiments, the condenser optical element and the collecting optical element may have the same focal length. In alternative embodiments, the condenser optical element and the collecting optical element may have a different focal length. Hence, in embodiments, the condenser optical element may have a condenser focal length. Similarly, in embodiments, the collecting optical element may have a collector focal length. In embodiments, the condenser focal length and the collector focal length may differ by at least 10%, such as by at least 15%, like by at least 20% relative to the smaller focal length of the two. Further, in embodiments, the condenser focal length and the collector focal length may differ by at most 150%, like by at most 100% relative to the smaller focal length of the two. An advantage thereof may be that a spot size of the focused beam comprising first device light on the diffuser may be set independently of the magnification of imaging optical elements (such as the collecting optical element) configured between the diffuser and the light exit.

[0041] In general, in embodiments, a longer focal length may be preferred for the condenser optical element as the incoming light may have less divergence. Conversely, in embodiments, to collect the reflectively diffused light which may have larger divergence angles, assuming a more or less constant maximum diameter of the incoming and outgoing collimated beams (and respective optical components), a (relatively) shorter focal distance may be preferred. Such embodiments may especially be advantageous in improving system efficiency. Furthermore, in such embodiments and optionally with an additional optical element (such as e.g. a lens) magnification to the system output may be set independently. In embodiments, the diffuser, the condenser optical element, and the collecting optical element may be configured such that the diffuser is in the focal plane of both the condenser optical element and the collecting optical element. This may, however, not necessarily be the case. The herein described non-collinear diffuser assembly may allow for more freedom in the choice of optical elements and their respective positions in the light generating system. In embodiments, the condenser lens may be configured to create a spot of first device light on (the surface of) the diffuser. Especially, in embodiments, the condenser lens may be configured to create a spot of first device light being either sharp, i.e., in focus, or vague, i.e., out-of-focus. Especially, in embodiments, the condensing optical element may thus be configured to create a spot of first device light onto a location differing between 2- 50% from the focal plane (of the condensing optical element), such as between 3-25%, like between 5-15%. Furthermore, in embodiments, a non-imaging condenser optical element with an out-of-focus placement of the diffuser may also be applied to reduce hot spots of the device light. The diffuser may, in embodiments, be configured to diffuse the device light, such that the angular distribution may be scrambled, while the spot size may be maintained. Conversely to the condenser optical element, in embodiments, for the collecting optical element applies that it may be configured to re-collimate light received from the diffuser. In embodiments, the collecting optical element may thus be configured to re-collimate a spot of diffused device light, which may be in the focal plane of the collector optical element or optionally not in the focal plane. Especially, in embodiments, the collecting optical element may thus be configured to re-collimate a spot of diffused device light onto a location differing between 2-50% from the focal plane (of the collecting optical element), such as between 3-25%, like between 5-15%. In some embodiments, the collecting optical element may (even) comprise two lenses, such that its focal strength may be improved. Hence, in embodiments, the diffuser may be configured out of a focal plane of one or more of the condenser optical element and the collecting optical element. Such embodiments may enable a wider range of spot sizes on the reflective diffuser and consequently a wider range of beam angles and the final cross-section dimensions of the outgoing diffused beam of first device light. Therewith, good color uniformity in the system light may be achieved.

[0042] Furthermore, in specific embodiments, the collecting optical element may have a minimum (optical) diameter (Dmin_ci), i .e. a minimum diameter of the clear aperture of the collecting optical element (e.g. lens). For example, in embodiments, the collecting optical element may have a minimum (optical) diameter (Dmin_ci) of at least 10 mm, such as at least 15 mm, especially at least 20 mm. The collecting optical element may further be configured at a (collecting lens) distance (dr ) defined from the diffuser along the (reflection) optical axis (OR). In embodiments, the (collecting lens) distance (dr ) may be selected from the range of 0.5-20 cm, such as from the range of 1-10 cm, like from the range of 2-8 cm. Especially, in embodiments, the (collecting lens) distance (dr ) may be selected from the range of 0.5-15 cm, such as from the range of 2-5 cm.

[0043] In embodiments, the diffused beam comprising the first device light (provided by the diffuser) may have a maximum cross-sectional diameter (Dmax_db) defined in a crosssection of the diffused beam at the (collecting lens) distance (d ). Especially, in embodiments, the maximum cross-sectional diameter (Dmax_db) may be defined as the minimum diameter comprising at least 90% of the optical power of the reflectively diffused first device light. In embodiments, the minimum (optical) diameter Dmin_ci) of the collecting optical element may be selected such that Dmin,ci>Dmax,db. Hence, in specific embodiments, the collecting optical element may have a minimum diameter (Dmin_ci), wherein the collecting optical element may be configured at a distance (di ) from the diffuser, wherein the diffused beam comprising the first device light may have a maximum cross-sectional diameter (Dmax db) defined in a cross-section of the diffused beam at the distance (dr ) from the diffuser; and wherein Dmin,ci>Dmax,db. In particular, in embodiments, as the diffuser increases the angular spread of the first device light, the minimum diameter of the collecting optical element may be larger than the first average cross-sectional diameter (defined by its FWHM and defined in a plane perpendicular to the first optical axis (Oi)) of the incoming beam of first device light. However, note that the diameter may further depend on the distances of lenses from the diffuser and their focal distances. Hence, with such embodiments as described herein, loss of light at the collecting optical element (due to the angular spreading of the diffuser) may be prevented.

[0044] Furthermore, in embodiments, the collecting optical element may comprise a material having low absorption for (at least) the spectral range of the first device light. Especially, in embodiments, the collecting optical element may comprise a material having an absorption coefficient selected from the range of <0.01 cm'1for (at least) the first peak wavelength (Xpi), i.e., for (at least) the spectral range of the first device light. More especially, in embodiments, the collecting optical element may comprise a material having an absorption coefficient selected from the range of <0.005 cm'1for (at least) the first peak wavelength (Xpi). The collecting optical element may for example comprise one or more materials selected from the group comprising: a glass (including e.g. fused silica), a polymeric material, and a ceramic material. Especially, the collecting optical element may comprise a light-transparent (solid) body. In specific embodiments, the collecting optical element comprises a glass material (e.g. a glass lens) having an absorption coefficient selected from the range of <0.01 cm’1for (at least) the first peak wavelength (Xpi).

[0045] In embodiments, the light generating system may thus be configured to generate, in an operational mode of the light generating system, system light comprising at least part of the collimated diffused beam comprising first device light. Hence, in embodiments, the first light generating device and the diffuser assembly may cooperate to provide diffused first device light at the light exit. In such embodiments, the system light may essentially have the first peak wavelength (Xpi), i.e., the system light may be blue light. Hence, in specific embodiments, the light generating system comprises a first light generating device, a diffuser assembly, optics, and a light exit, wherein: (A) the first light generating device is configured to generate first device light, wherein the first light generating device comprises a first solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (B) the diffuser assembly comprises a (small angle) diffuser, a (transmissive) condenser optical element, and a (transmissive) collecting optical element; (C) the condenser optical element is configured to provide a focused beam comprising first device light in an optical path to the diffuser; (D) the diffuser is configured in a light-receiving relationship with the condenser optical element; wherein the diffuser is configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element, wherein an optical axis (Oi) of the focused beam comprising first device light and an optical axis (OR) of the diffused beam comprising first device light have a mutual angle (P), wherein the mutual angle (P) is selected from the range of 80°<P<140°; (E) the collecting optical element is configured in a light-receiving relationship with the diffuser; wherein the collecting optical element is configured to provide a collimated diffused beam comprising first device light in an optical path to the light exit; and (F) the light generating system is configured to generate, in a first operational mode of the light generating system, system light comprising at least part of the collimated diffused beam comprising first device light.

[0046] The light generating system may thus, in embodiments, be configured to generate (the collimated diffused beam comprising) diffused first device light. Especially, in an operational mode of the light generating system, the light generating system may be configured to generate system light comprising at least part of the (collimated diffused beam comprising) diffused first device light. Further, in embodiments, the invention may provide a light generating system configured to provide system light having a different (i.e. with respect to the diffused first device light ) spectral power distribution. Especially, in embodiments, the light generating system may be configured to operate in a plurality of different operational mode. For example, in embodiments as described above, in an operational mode of the light generating system, the system light may be blue light. Alternatively, in embodiments, in an operational mode of the light generating system, the system light may be colored light, such as e.g. cyan, violet, or red light. Yet alternatively, in embodiments, in an operational mode of the light generating system, the system light may be white light. Hence, in specific embodiments, the light generating system may be configured to generate white system light (in an operational mode of the light generating system).

[0047] Therefore, the light generating system may, in embodiments, further comprise the second light generating device, the luminescent material, and the optics.

[0048] The second light generating device may, in embodiments, be configured to generate second device light. Therefore, in embodiments, the second light generating device may comprise a second light source. The second light source may be essentially any light source, see also further below. Especially, in embodiments, the (second light source of the) second light generating device may comprise a second solid state light source. Hence, in embodiments, the second light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The second solid state light source may be configured to generate second light source light. Especially, the second device light may essentially consist (of, especially comprise at least 95% of the radiant flux of the second light source light) of the second light source light. 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 (see also above) comprising a plurality of second lasers. The second device light may essentially consist (of, especially comprise at least 95% of the radiant flux of the second light source light) of the (laser) light of the laser diodes.

[0049] Further, in embodiments, the second light generating device may especially be configured to generate second device light having a second peak wavelength (Xp2). In embodiments, the second device light may essentially be any color light, such as e.g. blue light, red light, or a combination of different colors (e.g. white light). Especially, in embodiments, the second device light may have a second peak wavelength (Xp2) selected from the visible wavelength range, i.e., light having one or more wavelengths in the range of about 380-780 nm. In specific embodiments, the second device light may have a second peak wavelength (Xp2) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. More especially, in embodiments, the second device light may have a second peak wavelength (Xp2) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, the second device light may be blue light.

[0050] The second light generating device may especially be configured to provide second device light to the luminescent material. Hence, in embodiments, the luminescent material may be configured (optionally via one or more further (optical) elements) in lightreceiving relationship with the second light generating device. In other words, the luminescent material may be configured downstream of the second light generating device. In embodiments, the luminescent material may be configured to convert at least part of the second device light received by the luminescent material into luminescent material light. Especially, in embodiments, the luminescent material may be configured to convert at least 60%, such as at least 70%, especially at least 80%, more especially at least 90% of the second device light received by the luminescent material into luminescent material light. Further, in embodiments, the luminescent material may be configured to convert at most 100% of the second device light received by the luminescent material into luminescent material light.

[0051] 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.

[0052] In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation of a smaller wavelength is converted into radiation with a larger wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation of a larger wavelength is converted into radiation with a smaller wavelength ( x> m).

[0053] The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. When different luminescent materials are applied, one or more luminescent materials may be configured to convert incident light into one or more of green and yellow luminescent material light, and one or more other luminescent materials may be configured to convert incident light into one or more of orange and red luminescent material light. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. The term “luminescent material” herein may also refer to a material comprising a luminescent material, such as a light transmissive host comprising the luminescent material.

[0054] 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.

[0055] 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%.

[0056] The luminescent material may comprise an organic group that converts the light, or a molecule that converts the light, or an inorganic group that converts the light, etc. Such groups (or molecule) may be indicated as converter element. The garnet type material as indicated above, comprises cerium (Ce) as converter element. Cerium comprising garnets are well known in the art. Hence, in specific embodiments the luminescent material comprises a luminescent material of the type AsBsOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. 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.

[0057] In specific embodiments the luminescent material comprises (YXI-X2-X3A’X2CeX3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+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. 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.

[0058] 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.

[0059] In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+and / or LSisNs Eu2and / or MAlSi 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 divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba.

[0060] In embodiments, the luminescent material may comprise a luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, for instance comprising one or more of silicon and titanium, wherein X comprises a monovalent anion, at least comprising fluorine. A luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese is amongst others described in WO2013121355A1, which is herein incorporated by reference. Passages from WO2013121355A1 are also copied herein. Herein, M’xM2-2xAX6 doped with tetravalent manganese, may further also shortly be indicated as “phosphor”, i.e. the phrase " phosphor comprising M’xM2-2xAX6 doped with tetravalent manganese" may in an embodiment also be read as M’xM2-2xAX6 doped with tetraval ent manganese phosphor, or (tetraval ent) Mn-doped M’XM2-2XAX6 phosphor, or shortly "phosphor".

[0061] Relevant alkaline cations (M) are sodium (Na), potassium (K) and rubidium (Rb). Optionally, also lithium and / or cesium may be applied. In a preferred embodiment, M comprises at least potassium. In yet another embodiment, M comprises at least rubidium. The phrase “wherein M comprises at least potassium” indicates for instance that of all M cations in a mole M’xM2-2xAX6 , a fraction comprises K+and an optionally remaining fraction comprises one or more other monovalent (alkaline) cations (see also below). In another preferred embodiment, M comprises at least potassium and rubidium. Optionally, the M’XM2- 2xAXe luminescent material has the hexagonal phase. In yet another embodiment, the M’XM2- 2xAXe luminescent material has the cubic phase. Relevant alkaline earth cations (M’) are magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. In an embodiment, a combination of different alkaline cations may be applied. In yet another embodiment, a combination of different alkaline earth cations may be applied. In yet another embodiment, a combination of one or more alkaline cations and one or more alkaline earth cations may be applied. For instance, KRbo.sSro^sAXe might be applied. As indicated above, x may be in the range of 0-1, especially x<l. In an embodiment, x=0.

[0062] The term “tetravalent manganese” refers to Mn4+. This is a well-known luminescent ion. In the formula as indicated above, part of the tetravalent cation A (such as Si) is being replaced by manganese. Hence, M’xM2-2xAX6 doped with tetravalent manganese may also be indicated as M’xM2-2xAi-mMnmX6. The mole percentage of manganese, i.e. the percentage it replaces the tetravalent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12.

[0063] In an embodiment, M’xM2-2xAX6 comprises K^SiFe (indicated herein also as KSiF system). As indicated above, in another preferred embodiment, M’xM2-2xAX6 comprises KRbSiFe (herein also indicated as K,Rb system). As indicated above, part of silicon is replaced by manganese (i.e. the formula may also be described as K2Sii-mMnmF6 or KRbSii-mMrimFe, with m as indicated above, or as KRbSiFe:Mn and K2SiFe:Mn, respectively). As manganese replaces part of a host lattice ion and has a specific function, it is also indicated as “dopant” or “activator”. Hence, the hexafluorosilicate is doped or activated with manganese (Mn4+). In specific embodiments, the luminescent material may comprise (K,Rb)2SiFe:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2SiFe:Mn4+. Alternatively or additionally, in embodiments the third luminescent material may comprise K2TiFe:Mn4+. In embodiments, the third luminescent material may comprise K2(Si,Ti)Fe:Mn4+. As can be derived from the above, “ Si,Ti” may indicate one or more of Si and Ti.

[0064] 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.

[0065] 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.

[0066] The term “luminescent material” herein especially relates to inorganic luminescent materials.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] In embodiments, the luminescent material may be configured in the transmissive mode. In the transmissive mode, it may be relatively easy to have light source light admixed in the luminescent material light, which may be useful for generating the desirable spectral power distribution. In the reflective mode, thermal management may be easier, as a substantial part of the luminescent material may be in thermal contact with a thermally conductive element, like a heatsink or heat spreader. Hence, would any device light escape from the system, in embodiments this may only via transmission through the luminescent material. Hence, in embodiments, the luminescent material may be configured in the reflective mode.

[0071] In any case, in embodiments, the light generating system may comprise optics configured such that the collimated diffused beam of first device light, (i.e., diffused first device light) and the (collimated) luminescent material light may be provided to the light exit.

[0072] The term “optics” may especially refer to (one or more) optical elements. Hence, the terms “optics” and “optical elements” may refer to the same items. The optics may include one or more of mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, arrays of one or more of the aforementioned, 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”).

[0073] In embodiments, the optics may especially comprise one or more redirection optical elements. Hence, the optics may comprise optical elements configured to redirect light received by the redirection optical elements. In embodiments, one or more of the one or more redirection optical elements may be configured downstream of the first and / or second light generating device. As such, in embodiments, the one or more redirection optical elements may be configured to direct first device light (received by the redirection optical elements) in an optical path to the diffuser assembly. For example, in embodiments, the first light generating device and the second light generating device may be comprised by one laser bank and the one or more redirection optical elements may be configured (downstream of the one laser bank and configured) to direct the first device light (received by the redirection optical elements) in an optical path to the diffuser assembly. Analogously, in embodiments, the one or more redirection optical elements may be configured to direct second device light (received by the redirection optical elements) in an optical path to the luminescent material. For example, in embodiments, the first light generating device and the second light generating device may be comprised by one laser bank and the one or more redirection optical elements may be configured (downstream of the one laser bank and configured) to direct the second device light (received by the redirection optical elements) in an optical path to the luminescent material.

[0074] Additionally or alternatively, in embodiments, one or more of the one or more redirection optical elements may be configured downstream of the diffuser assembly. As such, in embodiments, the one or more redirection optical elements may be configured to direct the (collimated diffused beam comprising the) first device light (received by the redirection optical elements) in an optical path to the light exit. Additionally or alternatively, in embodiments, one or more of the one or more redirection optical elements may be configured downstream of the luminescent material. As such, in embodiments, the one or more redirection optical elements may be configured to direct the luminescent material light (received by the redirection optical elements) in an optical path to the light exit.

[0075] The light generating system may thus, in embodiments, be configured to generate (the collimated diffused beam comprising) diffused first device light and luminescent material light. Especially, in a first operational mode of the light generating system, the light generating system may be configured to generate system light comprising at least part of the (collimated diffused beam comprising) diffused first device light and at least part of the (collimated, see also further below) luminescent material light. In specific embodiment, the system light may thus be white light.

[0076] 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.

[0077] In embodiments, in an operational mode of the light generating system, the system light may especially be white light having a correlated color temperature selected from the range of 2000-10000 K, such as selected from the range of 6000-10000 K, like selected from the range of 6500-8000K. Additionally or alternatively, in embodiments, in an operational mode of the light generating system, the system light may especially be white light having a color rendering index of at least 60, such as at least 65. Further, in embodiments the system light may especially be white light having a color rendering index of at least 70, especially at least 80, more especially at least 90.

[0078] In specific embodiments, the light generating system comprises a (single) light generating device, a diffuser assembly, a luminescent material, optics, and a light exit, wherein: (A) the light generating device is configured to generate first device light and second device light, wherein the light generating device comprises a solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multijunction light-emitting diodes; (B) the diffuser assembly comprises a (small angle) diffuser, a (transmissive) condenser optical element, and a (transmissive) collecting optical element; (C) the condenser optical element is configured to provide a focused beam comprising first device light in an optical path to the diffuser; (D) the diffuser is configured in a lightreceiving relationship with the condenser optical element; wherein the diffuser is configured to provide a diffused beam comprising first device light in an optical path to the collecting optical element, wherein an optical axis (Oi) of the focused beam comprising first device light and an optical axis (OR) of the diffused beam comprising first device light have a mutual angle (P), wherein the mutual angle (P) is selected from the range of 80°<p<140°; (E) the collecting optical element is configured in a light-receiving relationship with the diffuser; wherein the collecting optical element is configured to provide a collimated diffused beam comprising first device light in an optical path to the light exit; (F) the luminescent material is configured to convert at least part of second device light received by the luminescent material into luminescent material light; (G) the optics comprise one or more redirection optical elements configured to direct one or more of: (i) the first device light in an optical path to the diffuser assembly, (ii) the collimated diffused beam comprising first device light in an optical path to the light exit, (iii) the second device light in an optical path to the luminescent material, and (iv) the luminescent material light in an optical path to the light exit; and (H) the light generating system is configured to generate, in a first operational mode of the light generating system, system light comprising at least part of the collimated diffused beam comprising first device light and at least part of the luminescent material light.

[0079] In embodiments, the system light may thus comprise a combination of diffused device light and luminescent material light. It may be desired to integrate (or angularly re-distribute) the different types of light, such that homogeneity of the system light may be improved. Therefore, in embodiments, the light generating system may further comprise a(t least one) transmissive integrator element. Especially, in embodiments, the diffuser assembly may comprise a transmissive integrator element. Herein, an integrator element may refer to an optical element configured to homogenize light received by the integrator element(, i.e., to provide a more uniform beam of light than the beam of light that was incident on the integrator element). The integrator element may herein especially be configured transmissive for the device light.

[0080] In embodiments, the transmissive integrator element may comprise a material selected from the group comprising: a glass material (having a high transmission in the first device light spectral range), a silicone-based material, a transparent ceramic material (such as e.g. sapphire), and a polymeric material. For example, in embodiments, the transmissive integrator element may comprise (etched) fused silica. In another example, in embodiments, the transmissive integrator element may comprise a(n engineered) substrate comprising a sol-gel coating. Especially, in embodiments, the transmissive integrator element may comprise one or more of an engineered diffuser (such as a flat-top, or top-hat diffuser), a gaussian(-like) diffuser, a holographic optical element, a micro-lens array, and a multi-lens array pair, such as a fly-eye lens array pair. Alternatively, in embodiments, the transmissive integrator element may comprise a (cross-sectional) polygonal light guide (or light mixing rod); such an integrating light guide. In such embodiments, the transmissive integrator element may be configured as a light tunnel comprising a hollow channel delimited by specularly reflective (cross sectional polygonal) walls such as mirror walls, or a (cross sectional polygonal) rod with in incoupling face and an opposite outcoupling face (both faces polygonal in cross-section) and (polygonal) side faces that provide total internal reflection of the guided light. Such integrators may, in embodiments, have as aspect ratio (AR) of length relative to a characteristic cross-sectional dimension (or diameter) characterized by AR>2, such as AR>4, in particular AR>6. Such integrators may provide in particular spatially redistributed (homogenized) light.

[0081] In embodiments, a transmissive integrator element may be configured downstream of the first light generating device and upstream of the condenser optical element (i.e. in between said components). Hence, in such embodiments, the transmissive integrator element may be configured in a light-receiving relationship with the first light generating device. The transmissive integrator element may especially be configured to (transmit and) (angularly and / or spatially) re-distribute the first device light received by the transmissive integrator element, such that a small-angle redistributed beam comprising the first device light may be provided. In embodiments, the transmissive integrator element may be configured to provide a small-angle redistributed beam comprising the first device light in an optical path to the condenser optical element. In turn, the condenser optical element may thus be configured in a light-receiving relationship with the transmissive integrator element. Hence, in specific embodiments, the diffuser assembly may further comprise a(t least one) transmissive integrator element; wherein the transmissive integrator element may be configured in a light-receiving relationship with the first light generating device; wherein the transmissive integrator may be configured to provide a small-angle redistributed beam comprising first device light in an optical path to the condenser optical element; and wherein the condenser optical element may be configured in a light-receiving relationship with the transmissive integrator element. Such embodiments may be beneficial as the transmissive integrator element may allow control of the size of the beam of light propagating from the transmissive integrator element through the system. Furthermore, the transmissive integrator element may provide a more uniformly distributed beam of light propagating from the transmissive integrator element through the system, which may improve efficiency of the light generating system.

[0082] As the device light emitted from the light generating devices (e.g. laser banks) may, in embodiments, comprise multiple narrow laser beams, each of said individual laser beams may represent a hot spot in the beam of device light. Focusing of such a beam of device light on e.g. a luminescent converter may exceed the maximum tolerable local irradiance and may result in damage to the luminescent material. Therefore, some homogenizing optics may be applied for each beam of device light to remove or reduce the hot spots. Hence, (angular and / or spatial) re-distribution of light such as described above may not only be beneficial to the diffuser assembly, but also to the conversion channel (i.e. luminescent material pathway) of the light generating system. Therefore, in embodiments, the light generating system may (also) comprise a transmissive integrator element configured in an optical path between the second light generating device and the luminescent material. For example, in embodiments, the transmissive integrator element may be configured between the second light generating device and the redirection optical elements. In another example, the transmissive integrator element may be configured between the redirection optical elements and the luminescent material. In some embodiments, the transmissive integrator element of the diffuser assembly and the transmissive integrator element of the converter channel may be essentially the same transmissive integrator element (e.g. when the first light generating device and the second light generating device are comprised by a single laser bank). However, in other embodiments, the transmissive integrator element of the diffuser assembly and the transmissive integrator element of the converter channel may be (multiple, i.e.) separate (or distinct) transmissive optical elements.

[0083] Additionally or alternatively, in embodiments, a reflective integrator element as described herein may be applied between the light generating devices and the luminescent material (i.e. in the conversion channel).

[0084] Furthermore, in embodiments, the light generating system may comprise additional transmissive integrator elements. For example, in embodiments, the light generating system may comprise a transmissive integrator element configured downstream of both the diffuser assembly and the luminescent material and upstream of the light exit. Hence, in such embodiments, the transmissive integrator element may be configured to integrate (or angularly and / or spatially re-distribute) (the diffused collimated beam of) diffused device light and (collimated) luminescent material light received by the transmissive integrator element into homogenized system light.

[0085] In embodiments, the (one or more) transmissive integrator element(s) may comprise a small-angle diffuser. Small-angle diffusers may have a dual functionality: a) define a spot diameter of light incident on the diffuser and / or the luminescent material, and b) reduce hot spots in the projected spot on the diffuser and / or the luminescent material. Especially, in embodiments, the transmissive integrator element may (comprise a small angle diffuser that may) be configured to re-distribute incoming (device) light such that the light may have a controlled (angular and / or spatial) re-distribution. Especially, in embodiments, the small-angle diffuser may be configured to re-distribute incoming (device) light such that the light may have a FWHM selected from the range of 1-50°, such as from the range of 2- 40°, like from the range of 3-30°, especially from the range of 5-20°. In embodiments, the incoming (device) light may comprise laser light. As such, the FWHM defined here for the re-distributed light may be an absolute FWHM. In embodiments, the transmissive integrator element (of the diffuser assembly) may thus comprise a small angle diffuser configured to redistribute incoming first device light, such that first device light propagating from the transmissive integrator may have a FWHM selected from the range of 1-50°. Similarly, in embodiments, other transmissive integrator elements comprised by the light generating system may comprise small-angle diffusers as described here. Hence, in embodiments, one or more of the following may apply: (i) the diffuser may comprise a small-angle diffuser, wherein the small-angle diffuser may be configured to re-distribute incoming first device light such that first device light, propagating from the diffuser to the collecting optical element, may have a full width half maximum (FWHM) selected from the range of 10-50° (such as configured to provide an angular spread of diffusion where as a function of a scatter angle 0, the intensity 1(9) of the diffused (or scattered) light may correspond to a function of cosn(9), wherein n may be selected from the range of 20-100), and (ii) the transmissive integrator may comprise a small angle diffuser, wherein the small angle diffuser may be configured to re-distribute incoming first device light, such that first device light propagating from the transmissive integrator may have a full width at half maximum (FWHM) selected from the range of 1-50°.

[0086] Furthermore, in embodiments, the transmissive integrator element may comprise a top-hat diffuser. Especially, in such embodiments, the top-hat diffuser may be configured to provide an angular distribution (of light) with a half-width-half-maximum (HWHM) selected from the range of 1-15°, such as from the range of 1-10°, like from the range of 2-8°, such as from the range of 3-6°, like e.g. a HWHM of 5°. Hence, a top-hat diffuser may provide a beam of light having a substantially constant irradiance profile through the cross-section of the beam.

[0087] In a specific example, in embodiments, (i) the condenser optical element and the collecting optical element both comprise aspheric lenses with optical diameters of 32.5 mm, (ii) the first light generating device may be configured to generate first device light having an average beam cross-sectional diameter of 26 mm, (iii) the transmissive integrator element comprises a top-hat diffuser configured to provide an angular distribution with a half-width-half-maximum (HWHM) of 5°, and (iv) the diffuser may be configured to redistribute incoming (first device) light such that as a function of a scatter angle 9, the intensity 1(9) of the diffused (or scattered) light may correspond to the cosn(9) function, wherein n may be selected from the range of n=20..100. Such embodiments may provide efficient collection of diffused device light, and expansion of the beam of first device light to an extent desired to match with the profile of luminescent material light provided by the luminescent material. Hence, as such, uniform color distribution of the resulting white beam of system light may be provided.

[0088] As described above, in embodiments, the diffuser may comprise one or more of a surface diffuser and a volume diffuser. For example, in embodiments, the reflective diffuser may comprise a plate comprising a diffusive material, i.e., comprising a light- diffusive surface. In alternative embodiments, the diffuser may comprise a transmissive holographic optical element or a micro-lens array. In yet alternative embodiments, the diffuser may comprise an inhomogeneous material comprising regions with different refractive index, where the light passing through this material may be scattered and / or refracted at the optical (refractive index) inhomogeneities in the material. Yet alternatively, in embodiments, the (reflective) diffuser may comprise an optical element wherein reflection occurs at the interface of (glass) material and air, i.e., based on total internal reflection (TIR). Hence, in embodiments, the diffuser may comprise a total internal reflector element.

[0089] Especially, in such embodiments, the total internal reflector element may comprise additional surface structuring (or texturing) configured to provide additional angular scattering (relative to the TIR). In other words, the total internal reflector element may comprise structuring on the surface, e.g. the surface may be rough, such that light may scatter from the surface. In embodiments, the additional surface structuring may comprise one or more of microstructuring, lamination, and metallization. Hence, in embodiments, the additional surface structuring may herein refer to either monolithic structuring, such as (i) an etched surface texture of the total internal reflector element, or (ii) additive micro-structuring, such as a texture-imprinted additional material layer (i.e., lamination) configured on the total internal reflector element.

[0090] The additional surface structuring may, in embodiments, be comprised by (or especially configured on) a transmissive surface (or transmissive plane) of the total internal reflector element. In such embodiments, the additional surface structuring may be configured on the plane (or surface) of the diffuser where (device) light may enter and / or may exit the diffuser, i.e., the total internal reflector element. Note that, in such embodiments, , , as the texturing may be configured on a transmissive surface of the total internal reflector element, said surface may not be a “true” total internal reflective surface, i.e., the total internal reflector element may be frustrated. As such, the total internal reflector element may maintain a slight chance that un(sufficiently) diffused device light would escape the element (and potentially the system). Hence, in embodiments where the additional surface structuring may be comprised by a transmissive surface (or transmissive plane) of the total internal reflector element, it may be desired to provide further optical elements (such as e.g. a reflector, a (specular) mirror, a transmissive integrator or optical sensors, see also described above) configured to provide an eye-safe light generating system.

[0091] Additionally or alternatively, in embodiments, the additional surface structuring may be comprised by (or especially configured on) a reflective surface (or a reflective plane) of the total internal reflector element. In such embodiments, the additional surface structuring may be configured on the plane (or surface) of the diffuser where (device) light may be reflected, such that it may escape the diffuser, i.e., the total internal reflector element, in an optical path to the light exit. Note that, in embodiments where the additional surface structuring may be configured on the reflective surface (or reflective plane) of the diffuser, it may be desired to additionally place a specular mirror downstream of (or behind) said reflective surface of the diffuser. In doing to, the specular mirror may allow re-use of light that would otherwise be lost, because the additional surface structuring on the internal surface may cause frustration of the total internal reflector element (i.e., the element may no longer be fully TIR for the incident light). Hence, in specific embodiments, the diffuser may comprise the combination of (i) a total internal reflector element with (ii) additional surface structuring; wherein the additional surface structuring may comprise one or more of microstructuring, lamination, and metallization; wherein the additional surface structuring may be comprised by a transmissive surface of the total internal reflector element and / or by a reflective surface of the total internal reflector element.

[0092] In embodiments, the focused beam comprising first device light may be incident on the reflective surface of the diffuser, such that the (incident) optical axis (Oi) may have an angle of about 45° relative to the reflective surface. However, other angles of the (incident) optical axis (Oi) with the reflective surface may herein not be excluded. Especially, in embodiments, the diffuser may comprise a solid optical element of essentially any shape comprising a total internal reflector element with additional surface structuring. In embodiments, the diffuser, especially the total internal reflector element, may comprise one or more of: a dome-shaped element, an aspherical lens, a spherical lens, a prism, a polyhedron (such as e.g. a tetrahedron), and an element with a (more) complex shape (such as e.g. an amorphous shape). In such embodiments, the main propagating direction of the incoming focused beam comprising first device light may be changed not by exactly 90°, but can be deflected by a larger angle, or alternatively by smaller angle, such as e.g. selected from the range of 80-140° (see also further above). Alternatively, in embodiments, the diffuser may comprise the total internal reflector element combined with at least one other (external) textured surface configured to provide the diffusion of light received by the diffuser. The diffuser may thus, in embodiments, work based on total internal reflection combined with angular scattering of the incoming focused beam of device light provided by the additional surface (micro-)structuring (or lamination of the engineered diffuser texture, with optional metallization). In specific embodiments, the diffuser may comprise the combination of (i) a total internal reflector element with (ii) additional surface structuring; wherein the total internal reflector element may comprise one of an aspherical lens, a spherical lens, a prism, and a polyhedron. As described above, the diffuser assembly may thus comprise a plurality of optical components. In embodiments, the different components of the diffuser assembly may be separate (or discrete) components. Alternatively, in embodiments, one or more of the different components of the diffuser assembly may be combined. Especially, in embodiments, the light generating system may comprise a monolithic body comprising one or more components of the diffuser assembly. In embodiments, the monolithic body may especially comprise a substantially light transparent material, such as e.g. a glass material. Especially, in embodiments, the monolithic body may comprise a light transmissive material or in other words an optically transmissive material. More especially, in embodiments the monolithic body may comprise a material with minimized optical absorbance and optionally also minimized optical scattering. Herein, however, in embodiments, small angle volume scattering may also be acceptable for the material of the monolithic body.

[0093] Moreover, in embodiments, the light generating system may comprise a monolithic (glass) body comprising the condenser optical element, the diffuser, and the collecting optical element. In such embodiments, the condenser optical element and / or the collecting optical element may e.g. comprise a lens-surface (see also above), i.e., may be integrated in the monolithic body. Therewith, the diffuser assembly may essentially be simplified as the singular monolithic body may essentially replace (i.e. eliminate) four glassair interfaces (of the otherwise separate optical components). In embodiments, the monolithic body may comprise a (substantially) spherical body comprising two (or more) flat(tened) surfaces. For example, in such embodiments, the monolithic body may comprise a sphere that has been cut tangentially in two (or more) locations. Especially, in embodiments, the monolithic body may comprise a sphere that has been cut tangentially in a number of locations selected from the range of 1-3, such as from the range of 1-2, like especially in 2 locations. In other words, in embodiments, the monolithic body may comprise a truncated ball (or sphere). In embodiments, the monolithic body comprising a sphere that has been cut tangentially in two (or more) locations may have a volume that may be reduced by 5-25%, such as 7.5-20% relative to a similar(-sized) sphere that was not cut. Especially, in embodiments where the mutual angle (P) may be 90°, the monolithic body may comprise two flat surfaces each cut at an angle of 22.5° relative to the (incident) optical axis (Oi) and the (reflection) optical axis (Oi), respectively. In embodiments where P 90°, the cut angles of the flat surfaces on the monolithic body may be slightly different, such as e.g. selected from the range of 10-35°, like from the range of 15-30°. Furthermore, in embodiments, the flat surfaces may be configured such that the monolithic body may be between 5-25%, such as between 7.5-20% smaller in volume than a similar(-sized) sphere that was not cut. Hence, in specific embodiments, the light generating system may comprise a monolithic body comprising the condenser optical element, the diffuser, and the collecting optical element; wherein the monolithic body may comprise two flat surfaces each cut at an angle of 22.5° relative to the optical axis (Oi) of the focused beam comprising first device light and the optical axis (OR) of the diffused beam, and wherein the monolithic body may comprise substantially light transparent material.

[0094] Furthermore, note that, in embodiments, a curvature of the monolithic body may not be the same over the full monolithic body. Hence, in such embodiments, the monolithic body may not necessarily resemble a sphere. Such embodiments may be beneficial as the differences in curvature may enable different effective focal lengths for the optical functions of the condenser and collecting optical elements configured within the monolithic body.

[0095] As described herein, the invention may not necessarily be limited to a (visible light, such as e.g. blue or orange) diffusive light channel. In embodiments, the light generating system may comprise a (blue, but optionally also other colors) diffusive light channel and a (yellow-green) conversion-based light channel, which may be combined into (white) system (output) light. Therefore, in embodiments, the first light generating device may be configured to provide first device light to the diffuser assembly and the second light generating device may be configured to provide second device light to the luminescent material. As indicated above, in embodiments, the first and second light generating devices may be configured in essentially the same laser bank. Hence, in embodiments, the first device light and the second device light may need to be separated in order to provide first device light and second device light to the diffuser assembly and the luminescent material, respectively. Additionally or alternatively, in embodiments, light from one (or both) of the first light generating device and the second light generating device may be divided over the diffuser channel and the luminescent material channel. Therefore, in embodiments, the one or more redirection optical elements may be selected from the group comprising: a dichroic beam redirector, a (partially) polarizing beam redirector, a geometric beam redirector, and a neutral beam redirector.

[0096] In embodiments, the dichroic beam redirector (or dichroic beam splitter) may be configured to transmit or reflect light received by the dichroic beam redirector in dependence of its spectral power distribution. For example, in embodiments, the dichroic beam redirector may be configured to (i) transmit (blue) device light received by the dichroic beam redirector (e.g. in an optical path to the luminescent material) and to (i) reflect (yellowgreen) luminescent material light received by the dichroic beam redirector (e.g. in an optical path to the light exit). Alternatively, in embodiments, the dichroic beam redirector may be configured to (i) reflect (blue) device light received by the dichroic beam redirector (e.g. in an optical path to the luminescent material) and to (i) transmit (yellow-green) luminescent material light received by the dichroic beam redirector (e.g. in an optical path to the light exit).

[0097] The (partially) polarizing beam redirector (or polarizing beam splitter) may, in embodiments, be configured to transmit or reflect light received by the polarizing beam redirector in dependence of its (linear) polarization. For example, in embodiments, the polarizing beam redirector may be configured to (i) transmit (blue) device light received by the polarizing beam redirector and comprising a first (linear) polarization (e.g. in an optical path to the luminescent material) and to (i) reflect (blue) device light received by the polarizing beam redirector and comprising a second (linear) polarization (e.g. in an optical path to the diffuser assembly). Herein, in embodiments, the first linear polarization and the second linear polarization may be different. In embodiments, the first polarization and the second polarization may be individually selected from s-polarization and p-polarization, or a combination therefor (especially in the case of a partially polarizing beam redirector) Alternatively, in embodiments, the polarizing beam redirector may be configured to (i) transmit (blue) device light received by the polarizing beam redirector and comprising a first (linear) polarization (e.g. in an optical path to the luminescent material) and to (i) reflect (blue) device light received by the polarizing beam redirector and comprising a second (linear) polarization (e.g. in an optical path to the diffuser assembly).

[0098] Furthermore, in embodiments, the geometric beam redirector (or geometric beam combiner, GBC) may be configured to transmit or reflect light received by the geometric beam redirector in dependence of its angle of incidence relative to spatial coordinates of a face of incidence of the geometric beam redirector. In other words, in embodiments, the geometric beam redirector (or geometric beam combiner) may be configured to transmit or reflect light received by the geometric beam redirector as a function of the location of incidence on the geometric beam redirector. Especially, in embodiments, the geometric beam redirector (or geometric beam combiner) may be configured to transmit or reflect light received by the geometric beam redirector in dependence of its angle of incidence relative to a surface normal (Ni) of the geometric beam redirector. Additionally or alternatively, in embodiments, the geometric beam redirector (or geometric beam combiner) may be configured to transmit or reflect light received by the geometric beam redirector in dependence of the local occurrence of total internal reflection or refraction of device light upon incidence from within the geometric beam redirector onto a GBC-air interface. In particular, the geometric beam redirector may be engineered such that light incident on different spatial locations on the geometric beam redirector may be differently redirected, e.g. transmitted or reflected. Especially, in embodiments, the geometric beam redirector may be engineered such that the transmissive and reflective optical features of the geometric beam redirector may be tailored to the geometries of the light sources in the light generating devices (e.g. the lasers in a laser bank). Therefore, in embodiments, the geometric beam combiner may comprise a plate comprising geometric-optical features that correlate to a geometrical configuration of the light sources in the light generating devices. In specific embodiments, the geometric beam combiner may comprise a plate comprising geometric- optical features that correlate to a geometrical distribution of the plurality of lasers in a laser bank. As such, in embodiments, the geometric beam redirector may be configured to combine device light received from two different optical paths (e.g. first device light and second device light orthogonally provided to the geometric beam redirector) into the same optical path (or direction). For example, in embodiments, the geometric beam redirector may be configured to combine first device light and second device light, orthogonally provided to the geometric beam redirector, in a same optical path to a further redirection optical element (such as e.g. a polarizing beam redirector). Such embodiments may be beneficial as optical power of different light generating devices may be combined without the need for expensive polarization based optical elements and / or differing wavelengths in the device light.

[0099] Yet further, in embodiments, the neutral beam redirector may be configured to transmit or reflect light received by the neutral beam redirector in dependence of Fresnel reflection of the light received by the neutral beam splitter, therewith resulting in (two) separate beams. In embodiments, the neutral beam redirector may especially comprise one or more stacks of dielectric layers configured to tune the beam splitting properties without specific (or intended) spectral or polarization preferences.

[0100] With embodiments as described above, the device light of different light generating devices may thus be divided over different optical channels in the light generating system and / or combined to improve optical power. Hence, such embodiments enable use of multiple light generating devices. In embodiments, the light generating system may therefore further comprise a third light generating device. The third light generating device may, in embodiments, be configured to generate third device light. Therefore, in embodiments, the third light generating device may comprise a third light source. The third light source may be essentially any light source, see also further below. Especially, in embodiments, the (third light source of the) third light generating device may comprise a third solid state light source. Hence, in embodiments, the third light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The third solid state light source may be configured to generate third light source light. Especially, the third device light may essentially consist (especially at least 95%) of the third light source light. The third light generating device may herein also comprise a plurality of third (solid state) light sources. Especially, in specific embodiments, the third light generating device may comprise a third laser bank comprising a plurality of third lasers. The third device light may essentially consist (especially comprise at least 95%) of the (laser) light of the laser diodes.

[0101] Further, in embodiments, the third light generating device may especially be configured to generate third device light having a third peak wavelength (Xp3). In embodiments, the third device light may essentially be any color light, such as e.g. blue light, red light, or a combination of different colors (e.g. white light). Especially, in embodiments, the third device light may have a third peak wavelength (Xp3) selected from the visible wavelength range, i.e., light having one or more wavelengths in the range of about 380-780 nm. In specific embodiments, the third device light may have a third peak wavelength (Xp3) selected from the wavelength range of 400-500 nm, such as from the range of 400-490 nm, like from the range of 430-490 nm. More especially, in embodiments, the third device light may have a third peak wavelength (Xp3) selected from the wavelength range of 440-490 nm, such as from the wavelength range of 450-480 nm. Hence, in embodiments, the third device light may be blue light.

[0102] In embodiments, the third light generating device may especially be configured to provide third device light (via the optics) to both the diffuser assembly and the luminescent material. For example, in embodiments, (i) the first light generating device may be configured to provide first device light to the diffuser assembly, (ii) the second light generating device may be configured to provide second device light to the luminescent material, and (iii) the third light generating device may be configured to provide third device light to the one or more redirection optical elements (e.g. in embodiments where at least the third device light is polarized light, the polarizing beam redirector), which may divide the third device light into a first part being provided to the diffuser assembly and a second part being provided to the luminescent material. The third light generating device may especially provide additional optical power to the light generating system, therewith improving the brightness and flux of the system light. Furthermore, the application of e.g. polarized third device light in combination with a polarizing beam redirector may allow for tuneability of the CCT of the system light, as the fraction of third device light in the diffuser channel versus the luminescent material channel may be controlled.

[0103] Therefore, in embodiments, the light generating system may further comprise a control system. The control system may especially be configured to control one or more of a correlated color temperature, a color rendering index, and a spectral power distribution of the system light. In embodiments, the control system may e.g. control said characteristics of the system light by controlling (the power of) one or more of the light generating devices.

[0104] Additionally or alternatively, in embodiments, the control system may e.g. control said characteristics of the system light by controlling the polarization of device light in the light generating system. Hence, in embodiments, the (first, second, and / or third) device light may comprise polarized light. In such embodiments, the light generating system may further comprise the polarizing beam redirector (see also further above). In embodiments, the polarizing beam redirector may be configured in a light-receiving relationship with the first light generating device and( / or) another one of the light generating devices (such as e.g. the second light generating device and / or the third light generating device). In such embodiments, (first, second, and / or third) device light reaching the polarizing beam redirector may comprise polarized light. The polarizing beam redirector may, in embodiments, be configured to transmit (at least part of, e.g. in the case of a partially polarizing beam splitter) device light comprising a first linear polarization. Additionally, in embodiments, the polarizing beam redirector may be configured to reflect (at least part of, e.g. in the case of a partially polarizing beam splitter) device light comprising a second linear polarization (different from the first linear polarization). Especially, in embodiments, the polarizing beam redirector may be configured to transmit device light having the first linear polarization in an optical path to one of the diffuser system and the luminescent material. Conversely, in embodiments, the polarizing beam redirector may be configured to reflect device light having the second linear polarization in an optical path to the other one of the diffuser system and the luminescent material. Hence, in embodiments, the polarizing beam redirector may comprise a polarizing beam splitter. Such embodiments may be beneficial as the polarizing beam redirector may e.g. allow splitting of device light from a single light generating device over both the diffuser channel and the conversion channel of the light generating system, therewith allowing optimal usage of the light generating devices while enabling a range of color points for the system light.

[0105] Furthermore, in such embodiments, the light generating system may further comprise a polarization control system. In embodiments, the polarization control system may comprise one or more of a birefringent rotator and a movement element.

[0106] The birefringent rotator may, in embodiments, be configured downstream of the first light generating device and upstream of the polarizing beam redirector. Additionally or alternatively, in embodiments, the birefringent rotator may be configured downstream of one or more of the other light generating devices and upstream of the polarizing beam redirector. The birefringent rotator may, in embodiments, comprise a X / 2 waveplate. However, in embodiments, other types of birefringent rotators (such as e.g. a X / 4 waveplate) may herein not be excluded. In embodiments, the control system may be configured to control the polarization control system. As such, in embodiments, the control system may be configured to control rotation of the birefringent rotator. By changing the orientation of the birefringent rotator relative to an optical axis of the device light received by the birefringent rotator, the polarization of said device light may change.

[0107] The movement element may, in embodiments, be configured to rotate the first light generating device. Additionally or alternatively, in embodiments, the movement element may be configured to rotate one or more of the other light generating devices. Therefore, in embodiments, the movement element may e.g. comprise an actuator. In embodiments, the control system may be configured to control the polarization control system. As such, in embodiments, the control system may be configured to control rotation of the light generating device(s) by controlling the movement element. By changing the orientation of the light generating devices relative to upstream configured optics (such as e.g. the polarizing beam redirector), the polarization of said device light propagating from the receiving optics (such as propagating from the polarizing beam redirector) may change.

[0108] Note that, in embodiments, the orientations of the birefringent rotator and / or the light generating devices as described above may also be factory set and fixated by a fixating means (such as e.g. a screw).

[0109] Hence, in specific embodiments, the light generating system may further comprise a polarizing beam redirector and a polarization control system, wherein: (A) the one or more light generating devices may comprise a first light generating device configured to generate the first device light, a second light generating device configured to generate the second device light, and optionally a third light generating device configured to generate third device light; (B) the polarizing beam redirector may be configured in a light-receiving relationship with the first light generating device and another one of the light generating devices, wherein (first, second, and / or third) device light reaching the polarizing beam redirector may comprise polarized light, and wherein the polarizing beam redirector may be configured (i) to transmit (at least part of) device light having a first linear polarization in an optical path to one of the diffuser system and the luminescent material and (ii) to reflect (at least part of) device light having a second linear polarization (different from the first linear polarization) in an optical path to the other one of the diffuser system and the luminescent material; (C) 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 polarizing beam redirector, wherein the control system may be configured to control rotation of the birefringent rotator; and wherein the birefringent rotator may comprises a X / 2 waveplate; and (b) a movement element configured to rotate the first light generating device, wherein the control system may be configured to control the movement element and / or control rotation of the birefringent rotator.

[0110] 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.

[0111] The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0112] 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.

[0113] 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.

[0114] 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).

[0115] 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.

[0116] 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.

[0117] In such applications, it may be desired to provide a light generating system that may be set to a variety of different CCTs. Therefore, in embodiments, the light generating system may further comprise a red light contribution to the system light.

[0118] Therefore, in embodiments, the light generating system may comprise a fourth light generating device. The fourth light generating device may, in embodiments, be configured to generate fourth device light. Therefore, in embodiments, the fourth light generating device may comprise a fourth light source. The fourth light source may be essentially any light source, see also further below. Especially, in embodiments, the (fourth light source of the) fourth light generating device may comprise a fourth solid state light source. Hence, in embodiments, the fourth light generating device may comprise one or more of a laser diode, a superluminescent diode, and a stacked multi -junction light-emitting diode (LED). The fourth solid state light source may be configured to generate fourth light source light. Especially, the fourth device light may essentially consist (especially at least 95%) of the fourth light source light. The fourth light generating device may herein also comprise a plurality of fourth (solid state) light sources. Especially, in specific embodiments, the fourth light generating device may comprise a fourth laser bank comprising a plurality of fourth lasers. The fourth device light may essentially consist (especially comprise at least 95%) of the (laser) light of the laser diodes.

[0119] Further, in embodiments, the fourth light generating device may especially be configured to generate fourth device light having a fourth peak wavelength (Xp4). Especially, in embodiments, the fourth device light may have a fourth peak wavelength (Xp4) selected from the wavelength range of 600-780 nm, such as from the range of 600-750 nm, like from the range of 620-700 nm. More especially, in embodiments, the fourth device light may have a fourth peak wavelength (Xp4) selected from the wavelength range of 600-700 nm, such as from the range of 620-660 nm. Hence, in embodiments, the fourth device light may be red light. Thanks to the addition of a (n orange-)red light generating device (i.e. orange-red fourth device light), the luminescent material may be chosen to have a luminescent color point that results in a suitable “phosphor load line” connecting the color points of the first, second, or third device light, or any interpolation between these and the luminescent light in the output (white or colored) light to achieve improved color rendering and / or improved luminescent conversion (e.g. minimization of droop) and / or improved gamut area (e.g. using lower wavelength luminescent green emission). As a consequence, a largely improved range of CCT values may be achieved, and even a large range of color points that are all located on the black body locus (BBL) may be realized.

[0120] The fourth light generating device may, in embodiments, be configured to provide fourth device light (optionally via the optics) to the diffuser assembly. Especially, in embodiments, the one or more redirection optical elements (such as e.g. a dichroic or geometric beam redirector) may be configured to combine the fourth device light into a same optical path with at least the first device light to the diffuser assembly. Hence, as such, the diffuser assembly may be configured in a light-receiving relationship with the fourth light generating device.

[0121] In embodiments, the diffuser assembly may thus be configured to diffuse not only blue device light, but also red device light. Especially, in embodiments, the diffuser assembly may be configured to the collimated diffused beam as described above but comprising both (diffused) first device light and (diffused) fourth device light. Hence, in embodiments, the diffuser assembly may be configured to diffuse (blue) first device light and (red) fourth device light, such that a collimated diffused beam as described above but comprising both (diffused) first device light and (diffused) fourth device light may be provided to the light exit.

[0122] In an operational mode of the light generating system, in embodiments, the light generating system may therefore be configured to generate white system light comprising at least part of the luminescent material light and at least part of the diffused collimated beam comprising both first device light and fourth device light. Hence, in specific embodiments, the light generating system may further comprise a fourth light generating device configured to generate fourth device light having a fourth peak wavelength (Xp4) selected from the range of 600-780 nm; wherein the fourth light generating device may comprise a fourth solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; and wherein (A) the one or more redirection optical elements may further be configured to combine the fourth device light into a same optical path with at least the first device light to the diffuser assembly; (B) the diffuser assembly may be configured to provide the collimated diffused beam comprising both first device light and fourth device light in an optical path to the light exit; and (C) the light generating system may be configured to generate in an operational mode of the light generating system white system light comprising at least part of the luminescent material light, at least part of the diffused collimated beam comprising both first device light and fourth device light.

[0123] Hence, in such embodiments, the light generating system may comprise a single diffuser assembly configured to diffuse both blue and red device light. Alternatively, in embodiments, the light generating system may comprise a second diffuser assembly. In such embodiments, the second diffuser assembly may especially be configured to diffuse the (red) fourth device light. The second diffuser assembly may, in embodiments, comprise essentially similar components as described for the diffuser assembly (for the blue first device light) further above. In particular, in embodiments, the second diffuser assembly may comprise a second (reflective) diffuser, a second transmissive integrator, a second condenser optical element, and a second collecting optical element. The second diffuser assembly may, in such embodiments, be configured to provide a second collimated diffused beam comprising fourth device light, i.e., diffused fourth device light. Therefore, in embodiments, the light generating system may be configured to generate in an operational mode system light further comprising at least part of the second collimated diffused beam comprising fourth device light. Hence, in specific embodiments, the light generating system may further comprise a fourth light generating device, and a second diffuser assembly, wherein: (A) the fourth light generating device may be configured to generate fourth device light (having a fourth peak wavelength (Xp4) different from the first peak wavelength (Xpi) and the second peak wavelength (Xp2), wherein the fourth light generating device may comprise a fourth solid state light source selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; (B) the second diffuser assembly may comprise a second (reflective) diffuser, a second transmissive integrator, a second condenser optical element, and a second collecting optical element; (C) the second transmissive integrator may be configured in a light-receiving relationship with the fourth light generating device; wherein the second transmissive integrator may be configured to provide a second small-angle redistributed integrated beam comprising fourth device light in an optical path to the second condenser lens; (D) the second condenser optical element may be configured in a light-receiving relationship with the second transmissive integrator; wherein the second condenser optical element may be configured to provide a second focused beam comprising fourth device light in an optical path to the second diffuser; (E) the second diffuser may be configured in a light-receiving relationship with the second condenser optical element; wherein the second diffuser may be configured to provide a second diffused beam comprising fourth device light in an optical path to the second collecting optical element; wherein an optical axis (0,2 of the second focused beam comprising fourth device light and an optical axis (OR?) of the second diffused beam comprising fourth device light may have a second mutual angle (P2), wherein the second mutual angle (P2) may be selected from the range of 80°<P2<140°; (F) the second collecting optical element may be configured in a light-receiving relationship with the second diffuser, and wherein the second collecting optical element may be configured to provide a second collimated diffused beam comprising fourth device light in an optical path to the light exit; (G) the one or more redirection optical elements may further be configured to direct the second collimated diffused beam comprising fourth device light in an optical path to the light exit; and (H) the light generating system may be configured to generate in an operational mode system light further comprising at least part of the second collimated diffused beam comprising fourth device light.

[0124] 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.

[0125] The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light. The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.

[0126] The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-490 nm wavelength range.

[0127] As indicated above, the light generating system comprises a light generating device. A light generating device may especially be configured to generate device light. Especially, the light generating device may comprise a light source. The light source may especially configured to generate light source light. In embodiments, the device light may essentially consist of the device light. In other embodiments, the device light may essentially consist of converted light source light. In yet other embodiments, the device light may comprise (unconverted) light source light and converted light source light. Light source light may be converted with a luminescent material into luminescent material light and / or with an upconverter into upconverted light (see also below). The term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions.

[0128] The term “light source” may in principle relate to any light source known in the art. The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources.

[0129] The light source may have a light escape surface. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source.

[0130] 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.

[0131] A position where system light escapes from the light generating system may also be indicated as light exit. This may be a light transmissive window or an opening (in the system). The light transmissive window may in embodiments be provided by an optical component.

[0132] 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).

[0133] 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. The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device).

[0134] 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.

[0135] 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.

[0136] 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.

[0137] 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.

[0138] 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.

[0139] The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the spectral wavelength range of 200-2000 nm, such as 300-1500 nm. The term “laser” especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.

[0140] 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).

[0141] Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of a semiconductor laser diodes, such as GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc.

[0142] 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.

[0143] 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.

[0144] 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. 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.

[0145] The beams (of light source light) may be focused or collimated beams of (laser) light source light. The term “focused” may especially refer to converging to a small spot. This small spot may be at the discrete converter region, or (slightly) upstream thereof or (slightly) downstream thereof. Especially, focusing and / or collimation may be such that the cross-sectional shape (perpendicular to the optical axis) of the beam at the discrete converter region (at the side face) is essentially not larger than the cross-section shape (perpendicular to the optical axis) of the discrete converter region (where the light source light irradiates the discrete converter region). Focusing may be executed with one or more optics, like (focusing) lenses. Especially, two lenses may be applied to focus the laser light source light. Collimation may be executed with one or more (other) optics, like collimation elements, such as lenses and / or parabolic mirrors. In embodiments, the beam of (laser) light source light may be relatively highly collimated, such as in embodiments <2° (FWHM), more especially <1° (FWHM), most especially <0.5° (FWHM). Hence, <2° (FWHM) may be considered (highly) collimated light source light. Optics may be used to provide (high) collimation (see also above).

[0146] 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.

[0147] 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.

[0148] 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. 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.

[0149] 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.

[0150] Superluminescent diodes are known in the art. A superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like an LED, while having a brightness in the order of a laser diode. Especially, a superluminescent diode may be a semiconductor light source, where the spontaneous emission light is amplified by stimulated emission in the active region of the device. Such emission is called “super luminescence”. Superluminescent diodes combine the high power and brightness of laser diodes with the low coherence of conventional lightemitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Superluminescent diodes may combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode.

[0151] 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 stage lighting device, a search light, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the light generating devices, the luminescent material, the diffuser assembly, and the optics.

[0152] Instead of the terms “lighting device” or “lighting system”, and similar terms, also the terms “light generating device” or “light generating system”, (and similar terms), may be applied. A lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”). As indicated above, the terms light and radiation may interchangeably be used.

[0153] BRIEF DESCRIPTION OF THE DRAWINGS

[0154] 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:

[0155] Figs. 1 schematically depict some aspects of the invention.

[0156] Figs. 2-5 further schematically depict some embodiments of the light generating system.

[0157] Fig. 6 schematically depicts some applications of the light generating system in lighting devices.

[0158] The schematic drawings are not necessarily to scale.

[0159] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0160] Figs. 1 schematically depicts a light generating system 1000 comprising one or more light generating devices 100, a diffuser assembly 1700, and a light exit 1090. As depicted, the one or more light generating devices 100 may comprise a first light generating device 110 configured to generate first device light 111. Therefore, in embodiments, the first light generating device 110 may comprise a first solid state light source 10. In specific embodiments, the first light generating device 110 may comprise a laser bank comprising a plurality of first lasers (i.e. a plurality of first solid state light sources 10).

[0161] Fig. 1 A depicts the light generating system 1000, wherein the diffuser assembly 1700 comprises a (small angle, reflective) diffuser 710, a (transmissive) condenser optical element 730, and a (transmissive) collecting optical element 740. In embodiments, the condenser optical element 730 may be configured in a light-receiving relationship with the first light generating device 110. The condenser optical element 730 may especially be configured to provide a focused (or condensed or convergent) beam 731 comprising first device light 111 in an optical path to the diffuser 710. The diffuser 710 may be configured in a light-receiving relationship with the condenser optical element 730. As such, in embodiments, the diffuser 710 may receive the focused beam 731 comprising first device light 111 and may be configured to provide a diffused beam 711 comprising first device light 111 in an optical path to the collecting optical element 740. The first device light 111 incident on the diffuser 710 may have an (incident) optical axis (Oi). Similarly, the (diffused) first device light 111, propagating from the diffuser 710 to the collecting optical element 740, may have an (reflection) optical axis (OR). In embodiments, the optical axis (Oi) of the focused beam 731 comprising first device light 111 and an optical axis (OR) of the diffused beam 711 comprising first device light 111 may have a mutual angle p. The mutual angle P may, in embodiments, be selected from the range of 80°<p<140°, such as e.g. as depicted P=90°. The diffused beam 711 comprising first device light 111 may propagate to the collecting optical element. In embodiments, the collecting optical element 740 may thus be configured in a light-receiving relationship with the reflective diffuser 710. The collecting optical element 740 may especially be configured to provide a collimated diffused beam 741 comprising first device light 111 in an optical path to the light exit 1090. As such, in embodiments the light generating system 1000 may be configured to generate in a first operational mode of the light generating system 1000 system light 1001 comprising at least part of the collimated diffused beam 741 comprising first device light 111.

[0162] In embodiments, the diffuser assembly 1700 may further comprise a(t least one) transmissive (small angle) integrator element 720. As depicted in fig. 1 A, in embodiments, the (at least one) transmissive integrator element 720 may be configured in a light-receiving relationship with the first light generating device 110. The transmissive integrator 720 may be configured to angularly redistribute the first device light 111 received by the transmissive integrator element 720. Hence, in embodiments, the transmissive integrator 720 may be configured to provide a small-angle redistributed beam 721 comprising first device light 111 in an optical path to the condenser optical element 730. Hence, as depicted, in embodiments, the condenser optical element 730 may be configured in a lightreceiving relationship with the transmissive integrator 720.

[0163] Furthermore, in embodiments, the diffuser 710 may comprise a small-angle diffuser. Especially, in such embodiments, the small-angle diffuser may be configured to redistribute incoming first device light 111 such that first device light 111, propagating from the diffuser 710 to the collecting optical element 740, may have a full width at half maximum (FWHM) selected from the range of 10-50° (such as configured to provide an angular spread of diffusion where as a function of a scatter angle 0, the intensity 1(9) of the diffused (or scattered) light may correspond to a function of cosn(9), wherein n may be selected from the range of 20-100). Additionally or alternatively, in embodiments, the transmissive integrator 720 may (also) comprise a small angle diffuser. However, in such embodiments, the small angle diffuser may be configured to re-distribute incoming first device light 111 such that first device light 111 propagating from the transmissive integrator 720 may have a full width at half maximum (FWHM) selected from the range ofl-50°.

[0164] The condenser optical element 730 and the collecting optical element 740 may essentially be the same type of optical element (e.g. lenses). However, in embodiments, the condenser optical element 730 and the collecting optical element 740 may differ in that the condenser optical element 730 and the collecting optical element 740 may have a different focal length (and / or may be configured at different (on-axis)di stances from the reflective diffuser 710). Although such embodiments may not exclude that in other embodiments, the condenser optical element 730 and the collecting optical element 740 may have essentially the same focal length (and / or are configured at essentially the same (on-axis) distances from the diffuser 710).

[0165] In embodiments, the collecting optical element 740 may have a (clear aperture having a) minimum diameter (Dmin_ci). Furthermore, the collecting optical element 740 may be configured at a (lens) distance (dr ) from the reflective diffuser 710, wherein the distance (df) may be defined between a location on the surface of the reflective diffuser where the (spot or) focused beam 731 comprising first device light I l l is incident (e.g. on an intersection of the optical axis OR with the diffuser 710) and a surface of the collecting optical element 740 nearest to the reflective diffuser 710 (e.g. on an intersection of the optical axis OR with the collecting optical element 740). In embodiments, the diffused beam 711 comprising the first device light 111 (provided by the diffuser 710) may have a maximum cross-sectional diameter (Dmax db) (defined by its full width half-maximum) defined in a cross-section of the diffused beam 711 at the distance (d ). In specific embodiments, Dmin,cl^Dmax,db, i.C., the collecting optical element 740 may be large enough to collect essentially all of the diffused beam 711 comprising the first device light 111 at the distance (dL).

[0166] The diffuser 710 is in Fig. 1A depicted as a plate, such as e.g. a planar surface diffuser. In embodiments, the diffuser 710 may comprise one (or more) of a reflective diffuser comprising a metalized structure surface, a white ceramic reflector, a combination of optical micro-structures (such as additional surface structuring 716) with a specular reflector 717 (such as e.g. depicted in Fig. IB subfigure II), a combination of a solid optical body with a diffuse reflector, a combination of a structured surface with a dichroic or thin film deposited reflector, and a combination of a total internal reflector element 715 with additional surface structuring 716 (see e.g. Figs. IB).

[0167] In specific embodiments, such as depicted in Figs. IB subfigures I and II, the diffuser 710 may comprise a solid optical body or a combination of a total internal reflector element 715 with additional surface structuring 716 providing diffused total internal reflection at one of its surfaces.. In embodiments, the total internal reflector element 715 may have essentially any shape, such as e.g. a polyhedron shape as depicted in subfigure I, or such as e.g. a dome shape as depicted in subfigure II. Especially, in embodiments, the total internal reflector element 715 may comprise one of a dome shaped element, an aspherical lens, a spherical lens , a prism, and a polyhedron, and an element with a (more) complex shape.

[0168] Hence, in embodiments, the diffuser 710 may comprise a combination of (i) a total internal reflector element 715 with (ii) additional surface structuring 716. In such embodiments, the additional surface structuring 716 may comprise one or more of microstructuring, lamination, and metallization. Especially, in embodiments, the additional surface structuring 716 may be comprised by (or especially configured on) a transmissive surface of the total internal reflector element 715 (such as depicted in Fig. IB subfigures I, II, and III), i.e., the plane (or surface) of the reflective diffuser 710 where first device light 111 may enter and / or exit the diffuser 710. Additionally or alternatively, in embodiments, the additional surface structuring 716 may be comprised by (or especially configured on) a reflective surface of the total internal reflector element 715 (such as depicted in Fig. IB subfigure II), i.e., the plane (or surface) of the diffuser 710 where first device light 111 may be reflected, such that it may escape the diffuser 710, in an optical path to the light exit 1090.

[0169] In the above described embodiments, the different components of the diffuser assembly 1700 may be separate components. Alternatively, in embodiments, such as depicted in Figs. IB subfigure III, the diffuser 710 may comprise a monolithic body 1750 comprising (two or more of) the condenser optical element 730, the diffuser 710, and the collecting optical element 740. In specific embodiments as depicted here, the monolithic body 1750 may comprises two flat surfaces each cut at an angle of 22.5° relative to the (incident) optical axis (Oi) and the (reflection) optical axis (Oi), respectively. In such embodiments, diffusion may occur at the two flat (internal reflection) surfaces. Hence, in embodiments, the monolithic body 1750 may comprise a truncated ball (or sphere). Additionally or alternatively, in such embodiments, diffusion may occur at the (external) surfaces, i.e., at the condenser optical element 730 and / or the collecting optical element 740. Moreover, the monolithic body 1750 may comprise substantially light transparent material (i.e. substantially transparent for at least the first device light).

[0170] Note that, in embodiments (not depicted), a reflective plane or surface of the diffuser 710 where first device light 111 may be reflected may be configured in a focal plane of both the condenser optical element 730 and the collecting optical element 740. Alternatively, in embodiments (not depicted), the reflective plane or surface of the diffuser 710 where first device light 111 may be reflected may be configured out of a focal plane of one or more of the condenser optical element 730 and the collecting optical element 740.

[0171] The light generating system 1000 may thus be configured to generate (blue and / or red) diffused device light. Furthermore, in embodiments, the light generating system may comprise a luminescent conversion channel. Especially, in embodiments, such as depicted in figs. 2-5, the invention may provide a light generating system 1000 comprising the first light generating device 110, a second light generating device 120, a luminescent material 200, the (first) diffuser assembly 1700, optics 500, and the light exit 1090.

[0172] In embodiments, the second light generating device 120 may be configured to generate second device light 121. Therefore, in embodiments, the second light generating device 120 may comprise a second solid state light source 20 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes. In specific embodiments, the first device light 111 and the second device light 121 may each have a peak wavelength individually selected from the range of 430-490 nm.

[0173] The luminescent material 200 may be configured downstream of at least the second light generating device 120. As such, in embodiments, the luminescent material 200 may be configured to convert at least part of second device light 121 received by the luminescent material 200 into luminescent material light 201. Further, in embodiments, the optics 500 may comprise one or more redirection optical elements 505. As depicted in Fig. 2, in embodiments, the one or more redirection optical elements 505 may be configured to direct the second device light 121 in an optical path to the luminescent material 200. Furthermore, in embodiments, the one or more redirection optical elements 505 may be configured to direct the luminescent material light 201 in an optical path to the light exit 1090. Yet further, in embodiments, the one or more redirection optical elements 505 may be configured to direct the collimated diffused beam 741 comprising first device light 111 in an optical path to the light exit 1090. Yet further, in embodiments such as depicted in Figs. 3 and 4, the one or more redirection optical elements 505 may be configured to direct the first device light 111 in an optical path to the diffuser assembly 1700.

[0174] The light generating system 1000 may thus be configured to generate in a first operational mode of the light generating system 1000 (white) system light 1001 comprising at least part of the collimated diffused beam 741 comprising first device light 111 and at least part of the (collimated) luminescent material light 201. Especially, in embodiments, in an 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 2000-10000 K and a color rendering index of at least 65.

[0175] Herein, reference 560 may refer to a lens, reference 570 may refer to a homogenizer, and reference 580 may refer to a (specular) reflector (e.g. a mirror). Furthermore, reference 1250 may refer to a heat sink.

[0176] In embodiments, the one or more redirection optical elements 505 may be selected from the group comprising: a dichroic beam redirector 515 (see e.g. figs. 2-5), a (partially) polarizing beam redirector 525 (see e.g. figs. 3 and 5), a neutral beam splitter (not depicted), and a geometric beam redirector 535 (see e.g. fig. 5).

[0177] In embodiments, the dichroic beam redirector 515 may be configured to transmit or reflect light received by the dichroic beam redirector 515 in dependence of its spectral power distribution. For example, as depicted in Fig. 2, the dichroic beam redirector 515 may be configured to reflect (blue) light (i.e. the diffused collimated beam 741 comprising first device light 111) and to transmit (yellow-green) luminescent material light 201.

[0178] In embodiments, a (partially) polarizing beam redirector 525 configured to transmit or reflect light received by the polarizing beam redirector 525 in dependence of its (linear) polarization. For example, as depicted in Fig. 3A, the polarizing beam redirector 525 may be configured to reflect device light having a first linear polarization, such as s- polarization here indicated with a black dot, and to transmit device light having a second linear polarization, such as p-polarization here indicated with an arrow. In Fig. 3 A, the polarizing beam redirector 525 may especially be configured to reflect second device light 121 and part of third device light 131b having the first linear polarization (see also below), and to transmit another part of third device light 131a having the second linear polarization (see also below).

[0179] The light generating system 1000 may further comprise a control system 300. In embodiments, the control system 300 may be configured to control one or more of a correlated color temperature, a color rendering index, and a spectral power distribution of the system light 1001.

[0180] Fig. 2 thus schematically depicts a light generating system 1000, wherein the (typically blue) second device light 121 from the second light generating device 120 may be directed via a dichroic beam redirector 515 to the luminescent material 200 operating in a reflective mode. Generated luminescent light 201 may be separated from the incident first device light 121 via the dichroic beam redirector 515 and may be projected to the light exit 1090. The (typically blue) first device light 111 from the first light generating device 110 may (by the diffuser assembly 1700) be (i) condensed and projected obliquely onto the diffuser 710, and (ii) collected and collimated in a direction different from the incident first device light 111. Via the dichroic beam redirector 515 the diffused collimated beam 741 comprising the first device light 111 may be combined with the luminescent material light 201 and projected to the light exit 1090.

[0181] In some embodiments, device light 111, 121(, 131, 141) may comprise polarized light, especially device light 111, 121 (,131, 141) reaching the polarizing beam redirector 525 may comprise polarized light. Therefore, in embodiments, the light generating system 1000 may comprise a polarization control system 600 configured to control the polarization of at least part of the device light. In embodiments, the polarization control system 600 may comprise a birefringent rotator 620 configured downstream of the first light generating device 110 (such as e.g. in fig. 3B subfigure II) and upstream of the polarizing beam redirector 525.

[0182] In embodiments, the birefringent rotator 610 may comprise a X / 2 waveplate. In embodiments, the control system 300 may be configured to control the orientation (by rotation) of the birefringent rotator 620. As such, in embodiments, the orientation of polarization of the first device light 111 reaching the polarizing beam redirector 525 may be controlled. Additionally or alternatively, in embodiments, the polarization control system 600 may comprise a movement element 610 (e.g. an actuator) configured to rotate the first light generating device 110, such as e.g. depicted in Fig. 3B subfigure I. Especially, in embodiments, the control system 300 may be configured to control the orientation of the first light generating device 110 by controlling the movement element 610. Additionally or alternatively, in embodiments, the movement element 610 may be configured to control one or more of the other light generating devices, such as e.g. as depicted in Fig. 3 A the third light generating device 130.

[0183] As depicted in Fig. 3B, in some embodiments, the one or more light generating devices may comprise a first light generating device 110 (e.g. a first laser bank) and a discrete second light generating device 120 (e.g. a second laser bank). In such embodiments, characteristics of the system light 1001 may be controllable through (i) individual control (or manipulation) of the (e.g. radiant flux) of the light generating devices 100, (ii) individual control (or manipulation) of light characteristics such as polarization of the device light 101,111,121 generated by the respective light generating devices 100,110,120 (e.g. using the polarization control system 600 as depicted in Figs. 3B), and / or (iii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating devices 100,110,120 (such as e.g. using the polarizing beam redirector 525).

[0184] Additionally or alternatively, in some embodiments, e.g. in the light generating system 1000 as depicted in Fig. IB subfigure I, the one or more light generating devices 100 may instead comprise a (single) light generating device 100 (e.g. a laser bank) comprising a multiple subsets of (solid state) light sources. For example, the (single) light generating device may comprise a laser bank comprising a first subset of first lasers 10 (which may also be referred to as the first light generating device 110) and a second subset of second lasers 20 (which may also be referred to as the second light generating device 120). In such embodiments, characteristics of the system light 1001 may be controllable through (i) individual control (or manipulation) of the (e.g. radiant flux) of the subsets of (solid state) light sources 10,20 in the light generating device 100, (ii) individual control (or manipulation) of light characteristics such as polarization of the device light 101,111,121 generated by the respective subsets of (solid state) light sources 10,20 in the light generating device 100 (e.g. using the polarization control system 600 as depicted in Figs. 3B), and / or (iii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating device 100 (such as e.g. using the polarizing beam redirector 525). Yet additionally or alternatively, in some embodiments, e.g. in the light generating system 1000 as depicted in Fig. IB subfigure I, the one or more light generating devices 100 may comprise a single light generating device 100 (e.g. a laser bank). In such embodiments, characteristics of the system light 1001 may be controllable through (i) control (or manipulation) of light characteristics such as polarization of the device light 101 generated by the light generating device 100 (e.g. using the polarization control system 600 as depicted in Figs. 3B), and / or (ii) control (or configuration) of optical (beam splitting / combining) components downstream of the light generating device 100 (such as e.g. using the polarizing beam redirector 525). For example, in such embodiments, optical (beam splitting / combining) components downstream of the light generating device 100 (such as e.g. using the polarizing beam redirector 525) may be configured to split the device light 101 provided by the light generating device 100 into first device light 111 and second device light 121, therewith splitting the device light 101 to provide part of the device light 101 to the luminescent material 200 and another part of the device light 101 to the diffuser assembly 1700.

[0185] The light generating system 1000 may further comprise a third light generating device 130 configured to generate third device light 131. Therefore, in embodiments, the third light generating device 130 may comprise a third solid state light source 30. In specific embodiments, the third light generating device 130 may comprise a laser bank comprising a plurality of third lasers (i.e. a plurality of third solid state light sources 30). The third device light 131 may, in embodiments, especially comprise blue device light.

[0186] Fig. 3 A schematically depicts a light generating system 1000 wherein polarizing components are used for the redistribution of device light over the conversion and diffusion channel. The (typically blue) linearly polarized second device light 121 from the second light generating device 120 may be directed via a first (possibly partly) polarizing beam redirector ((P)PBS) 525 and a dichroic beam redirector (DBS) 515 to the luminescent material 200 operating in a reflective mode. The second light generating device 120 may especially be configured such that the second device light 121, when arriving at the polarizing beam redirector 525, may be s-polarized. The luminescent light 201 may be separated from the optical path of the incident second device light 121 via the dichroic beam redirector 515 and from there projected to the light exit 1090. The (typically blue) linearly polarized third device light 131 from the third light generating device 130 may be split into a first (p-polarized or comprising both a p-polarization and an s-polarization component) part 131a that is projected via the dichroic beam redirector 515 to the luminescent material 200 and a second (s-polarized) part 131b projected via a second polarizing beam redirector 525 obliquely onto the diffuser 710. The split ratio depends on the direction of the polarization of the light emitted by the third light generating device 130, which can be adjusted via rotation of the third light generating device 130 around its optical axis by the movement element 610. The (typically blue) linearly polarized first device light 111 from the first light generating device 110 may be projected via the (specular) reflector 580 to the diffuser assembly 1700 as well. In embodiments, the first light generating device 110 may be configured such that the first device light 111 that it emits, when arriving at the (specular) reflector 580, may be p- polarized. The (by the diffuser assembly 1700) generated diffused beam 711 comprising (in this case) first device light 111 and third device light 131 may be collected and collimated in a direction different from the direction of the incident device light. Via the dichroic beam redirector 515 the diffused collimated beam 741 comprising (first and third) diffused device light may be combined with the luminescent material light 201 and projected to the light exit 1090. In alternative embodiments, not depicted here, the polarization direction of the third device light 131 may not be adjusted by rotation of the third light generating device 130, but it may be made adjustable via the birefringent rotator 620, being configured between the third light generating device 130 and the polarizing beam redirector 525.

[0187] As depicted in Fig. 4A, in embodiments, the light generating system 1000 may further comprise a fourth light generating device 140. The fourth light generating device 140 may, in embodiments, be configured to generate fourth device light 141 having a fourth peak wavelength ( p4) selected from the range of 600-780 nm. Therefore, in embodiments, the fourth light generating device 140 may comprise a fourth solid state light source 40 selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes.

[0188] In such embodiments, the one or more redirection optical elements 505 may further be configured to combine the fourth device light 141 into a same optical path with at least the first device light 111 to the diffuser assembly 1700. In further embodiments, the diffuser assembly 1700 may be configured to provide the collimated diffused beam 741 comprising both first device light 111 and fourth device light 141 in an optical path to the light exit 1090. 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 1001 comprising at least part of the luminescent material light 201, at least part of the diffused collimated beam 741 comprising both first device light 111 and fourth device light 141. Hence, in such embodiments, the diffuser assembly 1700 may be configured to diffuse both the first device light 111 and the fourth device light 141.

[0189] In alternative embodiments, such as depicted in Fig. 4B, the light generating system may comprise a second diffuser assembly 2700 configured to diffuse the fourth device light 141. In such embodiments, the second diffuser assembly 2700 may comprise a second (small angle, reflective) diffuser 2710, a second transmissive (small angle) integrator 2720, a second condenser optical element 2730, and a second collecting optical element 2740. In embodiments, the second transmissive (small angle) integrator 2720 may be configured in a light-receiving relationship with the fourth light generating device 140. Especially, the second transmissive (small angle) integrator 2720 may be configured to provide a second small-angle redistributed beam 2721 comprising fourth device light 141 in an optical path to the second condenser lens 2730. Further, in embodiments, the second condenser optical element 2730 may be configured in a light-receiving relationship with the second transmissive (small angle) integrator 2720. Further, in embodiments, the second condenser optical element 2730 may be configured to provide a second focused beam 2731 comprising fourth device light 141 in an optical path to the second diffuser 2710. Furthermore, in embodiments, the second diffuser 2710 may be configured in a lightreceiving relationship with the second condenser optical element 2730. In further embodiments, the second diffuser 2710 may be configured to provide a second diffused beam 2711 comprising fourth device light 141 in an optical path to the second collecting optical element 2740. Moreover, in embodiments, an optical axis (O,?) of the second focused beam 2731 comprising fourth device light 141 and an optical axis (OR?) of the second diffused beam 2711 comprising fourth device light 141 may have a second mutual angle (P2). Especially, the second mutual angle (P2) may be selected from the range of 80°<p2<140°. In further embodiments, the second collecting optical element 2740 may be configured in a light-receiving relationship with the second diffuser 2710 Furthermore, in embodiments, the second collecting optical element 2740 may be configured to provide a second collimated diffused beam 2741 comprising fourth device light 141 in an optical path to the light exit 1090. Further, in embodiments, the one or more redirection optical elements 505 may be further configured to direct the second collimated diffused beam 2741 comprising fourth device light 141 in an optical path to the light exit 1090. In further embodiments, the light generating system 1000 may be configured to generate in an operational mode system light 1001 that may further comprise at least part of the second collimated diffused beam 2741 comprising fourth device light 141. Fig. 5 schematically depicts a light generating system 1000 comprising the geometric beam redirector 535. In embodiments, the geometric beam redirector 535 may be configured to transmit or reflect light received by the geometric beam redirector 535 in dependence of its angle of incidence relative to spatial coordinates of a face of incidence of the geometric beam redirector. Especially, in embodiments, the geometric beam redirector 535 may be configured to transmit or reflect light received by the geometric beam redirector 535 in dependence of its angle of incidence relative to a surface normal (Ni) of the geometric beam redirector 535 .Additionally or alternatively, in embodiments, the geometric beam redirector 535 may be configured to transmit or reflect light received by the geometric beam redirector 535 in dependence of its total internal reflection relative to the geometric beam redirector 535. Especially, in embodiments, the geometric beam redirector 535 may be engineered such that the transmissive and reflective optical features of the geometric beam redirector 535 may be tailored to the geometries of the light sources in the light generating devices 110, 120, 130, 140 (e.g. the lasers in a laser bank). As such, in embodiments, the geometric beam redirector 535 may be configured to combine device light 111,121, 131,141 received from two different optical paths (e.g. first device light 111 and second device light 121 orthogonally (such as depicted here, or optionally even parallelly) provided to the geometric beam redirector 535) into the same optical path (or direction). For example, as depicted in Fig. 5, in embodiments, the geometric beam redirector 535 may be configured to combine third device light 131 and second device light 121, orthogonally provided to the geometric beam redirector 535, in a same optical path to a further redirection optical element 505 (such as e.g. a polarizing beam redirector 525). Note that, with the different components (or building blocks) described herein, it may be clear to the skilled person that a variety of different configurations may be provided as well, such as e.g. switching the luminescent material from a reflective configuration to a transmissive configuration, or different combinations of light sources with different redirection optical elements.

[0190] Fig. 6 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 6 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 6 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a stage lighting device, a search light, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall.

[0191] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species".

[0192] 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.

[0193] 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.

[0194] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0195] 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”.

[0196] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A light generating system (1000) comprising one or more light generating devices (100), a luminescent material (200), a diffuser assembly (1700), optics (500), and a light exit (1090), wherein: the one or more light generating devices (100) are configured to generate first device light (111) and second device light (121), wherein the one or more light generating devices (100) comprise one or more solid state light sources (10,20. . .) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction lightemitting diodes; the luminescent material (200) is configured to convert at least part of second device light (121) received by the luminescent material (200) into luminescent material light (201); the diffuser assembly (1700) comprises a diffuser (710), a condenser optical element (730), and a collecting optical element (740); the condenser optical element (730) is configured to provide a focused beam (731) comprising first device light (111) in an optical path to the diffuser (710); the diffuser (710) is configured in a light-receiving relationship with the condenser optical element (730); the diffuser (710) is configured to provide a diffused beam (711) comprising first device light (111) in an optical path to the collecting optical element (740); wherein an optical axis (Oi) of the focused beam (731) comprising first device light (111) and an optical axis (OR) of the diffused beam (711) comprising first device light (111) have a mutual angle (P), wherein the mutual angle (P) is selected from the range of 80°<p<140°; the collecting optical element (740) is configured in a light-receiving relationship with the diffuser (710); wherein the collecting optical element (740) is configured to provide a collimated diffused beam (741) comprising first device light (111) in an optical path to the light exit (1090); the optics (500) comprise one or more redirection optical elements (505) configured to direct one or more of: (i) the first device light (111) in an optical path to the diffuser assembly (1700), (ii) the collimated diffused beam (741) comprising first devicelight (111) in an optical path to the light exit (1090), (iii) the second device light (121) in an optical path to the luminescent material (200), and (iv) the luminescent material light (201) in an optical path to the light exit (1090); and the light generating system (1000) is configured to generate in a first operational mode of the light generating system (1000) system light (1001) comprising at least part of the collimated diffused beam (741) comprising first device light (111) and at least part of the luminescent material light (201).

2. The light generating system (1000) according to claim 1, wherein the one or more light generating devices (100) comprise a first light generating device (110) configured to generate the first device light (111) and a second light generating device (120) configured to generate the second device light (121); wherein the diffuser assembly (1700) further comprises a transmissive integrator element (720); wherein the transmissive integrator element (720) is configured in a light-receiving relationship with the first light generating device (110); wherein the transmissive integrator element (720) is configured to provide a small-angle redistributed beam (721) comprising first device light (111) in an optical path to the condenser optical element (730); and wherein the condenser optical element (730) is configured in a light-receiving relationship with the transmissive integrator element (720).

3. The light generating system (1000) according to any one of the preceding claims, wherein one or more of the following applies: (i) the diffuser (710) comprises a small-angle diffuser, wherein the small-angle diffuser is configured to re-distribute incoming first device light (111) such that first device light (111), propagating from the diffuser (710) to the collecting optical element (740), has a full width at half maximum (FWHM) selected from the range of 10-50°, and (ii) the transmissive integrator element (720), as defined in claim 2, comprises a small angle diffuser, wherein the small angle diffuser is configured to re-distribute incoming first device light (111) such that first device light (111) propagating from the transmissive integrator element (720) has a full width at half maximum (FWHM) selected from the range of 1-15°.

4. The light generating system (1000) according to any one of the preceding claims, wherein the one or more redirection optical elements (505) are selected from the group comprising:a dichroic beam redirector (515) configured to transmit or reflect light received by the dichroic beam redirector (515) in dependence of its spectral power distribution; a polarizing beam redirector (525) configured to transmit or reflect light received by the polarizing beam redirector (525) in dependence of its polarization; and a geometric beam redirector (535) configured to transmit or reflect light received by the geometric beam redirector (535) in dependence of one or more of (i) its angle of incidence relative to spatial coordinates of a face of incidence of the geometric beam redirector (535), and (ii) its total internal reflection relative to the geometric beam redirector (535).

5. 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) each have a peak wavelength individually selected from the range of 430-490 nm; and the light generating system (1000) further comprises a control system (300), wherein the control system (300) is configured to control one or more of a correlated color temperature, a color rendering index, and a spectral power distribution of the system light (1001); and wherein in an 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 2000-10000 K and a color rendering index of at least 65.

6. The light generating system (1000) according to any one of the preceding claims, wherein the condenser optical element (730) and the collecting optical element (740) have a different focal length.

7. The light generating system according to any one of the preceding claims, wherein the diffuser (710) comprises one of a small angle scattering metallic substrate, a white ceramic reflector, a patterned glass-based substrate with a reflective coating, a combination of optical micro-structures with a specular reflector (717), a combination of a solid optical body with a diffuse reflector, a combination of a structured surface with a dichroic or thin film deposited reflector, and a combination of a total internal reflector element (715) with additional surface structuring (716).

8. The light generating system (1000) according to claim 7, wherein the diffuser (710) comprises the combination of (i) a total internal reflector element (715) with (ii) additional surface structuring (716); wherein the additional surface structuring (716) comprises one or more of micro-structuring, lamination, and metallization; wherein the additional surface structuring (716) is comprised by a transmissive surface of the total internal reflector element (715) and / or by a reflective surface of the total internal reflector element (715).

9. The light generating system (1000) according to claim 7, wherein the diffuser (710) comprises the combination of (i) a total internal reflector element (715) with (ii) additional surface structuring (716); wherein the total internal reflector element (715) comprises one of an aspherical lens, a spherical lens, a prism, and a polyhedron providing diffused total internal reflection at one of its surfaces.

10. The light generating system (1000) according to any one of the preceding claims, comprising a monolithic body (1750) comprising the condenser optical element (730), the diffuser (710), and the collecting optical element (740); wherein the monolithic body (1750) comprises two flat surfaces each cut at an angle selected from the range of 15- 30° relative to the optical axis (Oi) of the focused beam (731) comprising first device light(111) and the optical axis (OR) of the diffused beam (711) comprising first device light (111), respectively, and wherein the monolithic body (1750) comprises substantially light transparent material.

11. The light generating system (1000) according to any one of the preceding claims, wherein the diffuser (710) is configured out of a focal plane of one or more of the condenser optical element (730) and the collecting optical element (740).

12. The light generating system (1000) according to any one of the preceding claims, further comprising a polarizing beam redirector (525) and a polarization control system (600), wherein: the one or more light generating devices (100) comprise a first light generating device (110) configured to generate the first device light (111), a second light generating device (120) configured to generate the second device light (121), and optionally a third light generating device (130) configured to generate third device light (131);the polarizing beam redirector (525) is configured in a light-receiving relationship with the first light generating device (110) and another one of the light generating devices (100), wherein device light (101) reaching the polarizing beam redirector (525) comprises polarized light, and wherein the polarizing beam redirector (525) is configured (i) to transmit device light having a first linear polarization in an optical path to one of the diffuser system (1700) and the luminescent material (200) and (ii) to reflect device light having a second linear polarization in an optical path to the other one of the diffuser system (1700) and the luminescent material (200); the polarization control system (600) comprises one or more of (a) a birefringent rotator (620) configured downstream of the first light generating device (110) and upstream of the polarizing beam redirector (525), wherein the control system (300) as defined in claim 5 is configured to control rotation of the birefringent rotator (620); and wherein the birefringent rotator (610) comprises a X / 2 waveplate; and (b) a movement element (610) configured to rotate the first light generating device (110), wherein the control system (300) as defined in claim 5 is configured to control the movement element (610) and / or control rotation of the birefringent rotator (620).

13. The light generating system (1000) according to any one of the preceding claims, wherein the one or more light generating devices (100) further comprise a fourth light generating device (140), wherein: the fourth light generating device (140) is configured to generate fourth device light (141) having a fourth peak wavelength ( p4) selected from the range of 600-780 nm; wherein the fourth light generating device (140) comprises a fourth solid state light source (40) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; and the one or more redirection optical elements (505) are further configured to combine the fourth device light (141) into a same optical path with at least the first device light (111) to the diffuser assembly (1700); the diffuser assembly (1700) is configured to provide the collimated diffused beam (741) comprising both first device light (111) and fourth device light (141) in an optical path to the light exit (1090); and the light generating system (1000) is configured to generate in an operational mode of the light generating system (1000) white system light (1001) comprising at least partof the luminescent material light (201), at least part of the diffused collimated beam (741) comprising both first device light (111) and fourth device light (141).

14. The light generating system (1000) according to any one of the preceding claims 1-12, wherein the one or more light generating devices (100) further comprise a fourth light generating device (140), and a second diffuser assembly (2700), wherein: the fourth light generating device (140) is configured to generate fourth device light (141), wherein the fourth light generating device (140) comprises a fourth solid state light source (40) selected from the group comprising laser diodes, superluminescent diodes, and stacked multi -junction light-emitting diodes; the second diffuser assembly (2700) comprises a second diffuser (2710), a second transmissive integrator (2720), a second condenser optical element (2730), and a second collecting optical element (2740); the second transmissive integrator (2720) is configured in a light-receiving relationship with the fourth light generating device (140); wherein the second transmissive integrator (2720) is configured to provide a second small-angle redistributed beam (2721) comprising fourth device light (141) in an optical path to the second condenser lens (2730); the second condenser optical element (2730) is configured in a light-receiving relationship with the second transmissive integrator (2720); wherein the second condenser optical element (2730) is configured to provide a second focused beam (2731) comprising fourth device light (141) in an optical path to the second diffuser (2710); the second diffuser (2710) is configured in a light-receiving relationship with the second condenser optical element (2730); wherein the second diffuser (2710) is configured to provide a second diffused beam (2711) comprising fourth device light (141) in an optical path to the second collecting optical element (2740); wherein an optical axis (0,2) of the second focused beam (2731) comprising fourth device light (141) and an optical axis (OR?) of the second diffused beam (2711) comprising fourth device light (141) have a second mutual angle (|32), wherein the second mutual angle (P2) is selected from the range of 80°<p2<140°; the second collecting optical element (2740) is configured in a light-receiving relationship with the second diffuser (2710), and wherein the second collecting optical element (2740) is configured to provide a second collimated diffused beam (2741) comprising fourth device light (141) in an optical path to the light exit (1090);the one or more redirection optical elements (505) are further configured to direct the second collimated diffused beam (2741) comprising fourth device light (141) in an optical path to the light exit (1090); and the light generating system (1000) is configured to generate in an operational mode system light (1001) further comprising at least part of the second collimated diffused beam (2741) comprising fourth device light (141).

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

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