Laser-phosphor light engine for stage-lighting using a diffuser in the transmissive mode

Abstract

The invention provides a light generating system (1000) comprising a first laser light source (110), a second laser light source (120), optics (500), a luminescent material (200) and a diffuser element (400), wherein: (A) the first laser light source (110) is configured to generate first laser light (111) having a first peak wavelength (λp1) selected from the range of 430-490 nm; (B) the second laser light source (120) is configured to generate second laser light (121) having a second peak wavelength (λp2) selected from the range of 430-490 nm; (C) the optics (500) comprises (i) a first optical element (510), configured downstream of the first laser light source (110), and (ii) a second optical element (520), configured downstream of the first optical element (510); (D) the luminescent material (200) is configured downstream of the first optical element (510), wherein the luminescent material (200) is configured to convert at least part of the first laser light (111) into luminescent material light (201), such that at least part of the luminescent material light (201) propagates to the second optical element (520); wherein one of the following applies: (i) the first optical element (510) is configured to (a) at least partially transmit the first laser light (111), (b) at least partially reflect the luminescent material light (201); (ii) the first optical element (510) is configured to (a) at least partially reflect the first laser light (111), (b) at least partially transmit the luminescent material light (201); (E) the diffuser element (400) is configured downstream of the second laser light source (120), wherein the diffuser element (400) is configured to transmit and diffuse at least part of the second laser light (120) such that diffused laser light (401) propagates to the second optical element (520); (F) the second optical element (520) is configured to combine at least part of the luminescent material light (201) and at least part of the diffused laser light (401) into a same optical path; and (G)the light generating system (1000) is configured to generate system light (1001) comprising at least part of the luminescent material light (201) and at least part of the diffused laser light (401).

Description

[0001] Laser-phosphor light engine for stage-lighting using a diffuser in the transmissive mode

[0002] FIELD OF THE INVENTION

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

[0004] BACKGROUND OF THE INVENTION

[0005] Laser-phosphor based stage lighting fixtures are known in the art. For instance, WO2022143318 describes a light emitting device, comprising a first light source, a second light source, a dichroic mirror, a wavelength conversion apparatus, a first light path adjusting apparatus or a second light path adjusting apparatus, and a first scattering optical system. The light mixing effect of emergent light can be improved by using the first scattering optical system. Light emitted by the first light source is all used for exciting the wavelength conversion apparatus.

[0006] SUMMARY OF THE INVENTION

[0007] High brightness light sources can be used in various applications including spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. Stage lighting fixtures use high-brightness extreme-cool-white light sources such as discharge lamps. Alternatively, for this purpose, laser-phosphor technology can be used, wherein a laser provides laser light and a remote phosphor converts laser light into converted light. A relatively straightforward way to produce white light using lasers is to use (blue) laser light in combination with a (yellow) phosphor to generate phosphor converted light. Laser-phosphor systems may allow generation of high brightness light and may therefore be used in projection systems, including displays such as cinema projectors and projectors for home, school, and office applications, car front lighting, search lighting, stage lighting, architectural lighting, and special lighting applications. A way to combine pump light and luminescent light may be to use a polarizing beam splitter for the pump light, by which part of the light is reflected to the luminescent material and part is transmitted to a diffuser. However, in general the diffused light may to a large degree be depolarized, which may result in relatively high losses of diffused blue light at the beam combiner where it is combined with the luminescent light into white output light. Hence, it may be desired to improve the performance of stage lighting fixtures. Further, the phosphors in laser-phosphor lighting systems may suffer from droop. Droop in phosphors is a phenomenon describing their tendency to lose efficiency as the light flux increases due to excited-state up-conversion losses. Hence, it is desired to provide a light generating system with tunable color temperature and tunable spectral properties while limiting droop.

[0008] Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0009] According to a first aspect, the invention provides a light generating system comprising a first laser light source, a second laser light source, optics, a luminescent material, and a diffuser element. In embodiments, the first laser light source may be configured to generate first laser light. Especially, in embodiments, the first laser light may have a first peak wavelength (Xpi) selected from the range of 430-490 nm. Similarly, in embodiments, the second laser light source may be configured to generate second laser light. Especially, in embodiments, the second laser light may have a second peak wavelength (XPi) selected from the range of 430-490 nm. Further, in embodiments, the optics may comprise a first optical element configured downstream of the first laser light source. Additionally, in embodiments, the optics may comprise a second optical element configured downstream of the first optical element. Furthermore, in embodiments, the luminescent material may (also) be configured downstream of the first optical element. The luminescent material may especially be configured to convert at least part of the first laser light (received by the luminescent material) into luminescent material light. In embodiments, the luminescent material light may propagate from the luminescent material (via the first optical element) to the second optical element. Hence, in embodiments, the luminescent material may be configured to convert at least part of the first laser light (received by the luminescent material) into luminescent material light such that the luminescent material light may propagate from the luminescent material to the second optical element. In embodiments, the first optical element may be configured to at least partially transmit the first laser light (received by the first optical element) and to at least partially reflect the luminescent material light (received by the first optical element). Alternatively, in embodiments, the first optical element may be configured to at least partially reflect the first laser light (received by the first optical element) and to at least partially transmit the luminescent material light (received by the first optical element). Further, in embodiments, the diffuser element may be configured downstream of the second laser light source. Especially, in embodiments, the diffuser element may be configured to transmit and diffuse at least part of the second laser light (received by the diffuser element). More especially, in embodiments, the diffuser element may be configured to transmit at least part of the second laser light (received by the diffuser element) such that (transmitted) diffused laser light propagates to the second optical element. The second optical element may, in embodiments, be configured to combine at least part of the luminescent material light (received via the first optical element) and at least part of the (transmitted) diffused laser light (received via the first diffuser element). Especially, in embodiments, the second optical element may be configured to combine at least part of the luminescent material light and at least part of the (transmitted) diffused laser light (received via the first optical element and the first diffuser element, respectively) into a same optical path. Furthermore, in embodiments, the light generating system may be configured to generate system light. In embodiments, the system light may especially comprise at least part of the luminescent material light and at least part of the (transmitted) diffused laser light (combined by the second optical element). Hence, in embodiments, the invention provides a light generating system comprising a first laser light source, a second laser light source, optics, a luminescent material and a diffuser element, wherein: (A) the first laser light source may be configured to generate first laser light having a first peak wavelength (XPi) selected from the range of 430-490 nm; (B) the second laser light source may be configured to generate second laser light having a second peak wavelength (XP2) selected from the range of 430-490 nm; (C) the optics may comprise (i) a first optical element, configured downstream of the first laser light source, and (ii) a second optical element, configured downstream of the first optical element; (D) the luminescent material may be configured downstream of the first optical element, wherein the luminescent material may be configured to convert at least part of the first laser light into luminescent material light, such that at least part of the luminescent material light may propagate to the second optical element; wherein one of the following applies: (i) the first optical element may be configured to (a) at least partially transmit the first laser light, (b) at least partially reflect the luminescent material light; and (ii) the first optical element may be configured to (a) at least partially reflect the first laser light, (b) at least partially transmit the luminescent material light; (E) the diffuser element may be configured downstream of the second laser light source, wherein the diffuser element may be configured to transmit and diffuse at least part of the second laser light such that (transmitted) diffused laser light propagates to the second optical element; (F) the second optical element may be configured to combine at least part of the luminescent material light and at least part of the (transmitted) diffused laser light into a same optical path; and (G) the light generating system may be configured to generate system light comprising at least part of the luminescent material light and at least part of the (transmitted) diffused laser light.

[0010] Hence, instead of using a blue laser light diffuser in the reflective mode, the diffuser is used to transmit and scatter blue laser light. The scattered blue laser light can be combined with phosphor converted light downstream using a dichroic mirror. With such a light generating system both blue laser light polarizations are used, and thus increasing the efficiency of the light generating system compared to a system using the blue laser light diffuser in the reflective mode (in which system light of one blue laser light polarization is lost). Furthermore, with such system, a high-power light generating system may be provided. Further, such system may allow control of spectral power distribution of the system light (of a high-power system). Yet, such system may in a safe way provide high power light. The system may be relatively compact. Yet, thermal management of the luminescent material may also be provided with this system. In addition to high optical power, the system may also provide high radiance (or luminance), i.e., a high optical power density of the source. Hence, such a system as described here may provide a high brightness laser-phosphor light engine for stage-lighting using a blue laser light diffuser in the transmissive mode. Furthermore, with such system, an eye-safe high-brightness light generating system may be provided.

[0011] The light generating system may thus comprise a first laser light source, a second laser light source, optics, a luminescent material, and a diffuser element. Here below, embodiments of the different components of the light generating system will be described in further detail.

[0012] The first laser light source may be configured to generate first laser light having a first peak wavelength (XPi). In embodiments, the first peak wavelength (XPi) may be selected from the wavelength range of 430-490 nm. Especially, in embodiments, the first peak wavelength (XPi) may be selected from the range of 440-490 nm, such as from the range of 450-480 nm, like from the range of 455-470 nm. In specific embodiments, the first peak wavelength (XPi) may be selected from the wavelength range of 435-465 nm. Hence, in embodiments, the first laser light may be blue light. Similarly, the second laser light source may be configured to generate second laser light having a second peak wavelength (XP2). In embodiments, the second peak wavelength (XP2) may be selected from the wavelength range of 430-490 nm. Especially, in embodiments, the second peak wavelength (XP2) may be selected from the range of 440-490 nm, such as from the range of 450-480 nm, like from the range of 455-470 nm. In specific embodiments, the second peak wavelength (XP2) may be selected from the wavelength range of 435-465 nm. The first peak wavelength (XPi) and the second peak wavelength (XP2) may especially be individually selected from the wavelength range of 435-465 nm. Hence, in embodiments, the second laser light may (also) be blue light. Yet, the peak wavelengths may in embodiments essentially be the same or may in embodiments differ.

[0013] As indicated above, 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.

[0014] In embodiments, the first laser light source and the second laser light source may be identical light sources. 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. Alternatively, in embodiments, the first laser light source and the second laser light source may be different light sources. 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.

[0015] Furthermore, the term “laser light source” may in embodiments refer to a single laser light source, but may in other embodiments 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 below)(which may by definition comprise a plurality of laser light sources). Laser banks may also be used to boast the input power. Therefore, in embodiments the system may comprise a plurality of light generating devices configured in a laser bank. 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 laser bank may thus in embodiments comprise a heat sinking element and / or lasing 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. Hence, in embodiments, the light generating system may comprise a laser bank comprising a heat sinking element and lasing optics.

[0016] In embodiments, the term “first laser light source” may also refer to a plurality of first laser light sources, such as a plurality of first lasers. Especially, in embodiments, the first laser light source may refer to a first laser bank comprising a plurality of first lasers. The first laser bank may further, in embodiments, comprise a first laser bank heat sink configured to provide heat dissipation during operation of the first laser bank. Additionally or alternatively, in embodiments, the first laser bank may comprise a first laser bank optical arrangement configured to collimate the laser light generated by the plurality of first lasers. Hence, in embodiments, the first laser light source may comprise a first laser bank comprising a first laser bank heat sink, a first laser bank optical arrangement, and a plurality of first lasers. Especially, in embodiments, the first laser bank heat sink may be configured in thermal contact with the plurality of first lasers.

[0017] Similarly, in embodiments, the term “second laser light source” may also refer to a plurality of second laser light sources, such as a plurality of second lasers. Especially, in embodiments, the second laser light source may refer to a second laser bank comprising a plurality of second lasers. The second laser bank may further, in embodiments, comprise a second laser bank heat sink configured to provide heat dissipation during operation of the second laser bank. Additionally or alternatively, in embodiments, the second laser bank may comprise a second laser bank optical arrangement configured to collimate the laser light generated by the plurality of second lasers. Hence, in embodiments, the second laser light source may comprise a second laser bank comprising a second laser bank heat sink, a second laser bank optical arrangement, and a plurality of second lasers. Especially, in embodiments, the second laser bank heat sink may be configured in thermal contact with the plurality of second lasers. Additionally or alternatively, in embodiments, the first laser light source and the second laser light source may be combined into one laser light arrangement, such as into one laser bank. Hence, in embodiments, the first laser bank and the second laser bank may be essentially the same laser bank. In such embodiments, the first laser light source and the second laser light source may be combined into one laser light arrangement (e.g. laser bank) having an array first lasers and second lasers. In embodiments, the laser light arrangement may be configured to generate laser light being divided into a first light beam (of first laser light) and a second light beam (of second laser light).

[0018] In embodiments, in an operational mode of the light generating system, the optics may be configured downstream of (both) the first laser light source and the second laser light source. The optics may, in embodiments, comprise a first optical element and a second optical element. The first optical element may especially be configured downstream of the first laser light source. Furthermore, the second optical element may be configured downstream of the first optical element.

[0019] 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”.

[0020] The first optical element may thus, in embodiments, be configured in a lightreceiving relationship with the first laser light source. Especially, the first optical element may be configured to at least partially transmit the first laser light (received by the first optical element). Additionally or alternatively, the first optical element may be configured to at least partially reflect the first laser light (received by the first optical element). The first optical element may, for example, comprise a beam splitter, such as a dichroic or a polarizing beam splitter, see also further below. In embodiments, the first laser light at least partially transmitted and / or reflected by the first optical element may propagate to the luminescent material. Especially, in embodiments, at least 60% of the first laser light (received by the first optical element) may propagate to the luminescent material, such as at least 70%, like at least 80%, especially at least 90%, including 100%. Further, in such embodiments, essentially no second laser light may propagate (via the first optical element) to the luminescent material. However, in alternate embodiments this may not necessarily be the case, see also further below. The phrase “... light received by ...”, and similar phrases, such as “light source light received by the first luminescent material” may especially indicate that when the light is actually received by an item, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. Further, the action may also include refraction.

[0021] The luminescent material may thus, in embodiments, be configured downstream of the first optical element (such that the luminescent material may be configured in a light-receiving relationship with the first optical element). In embodiments, the luminescent material may be configured to convert at least part of the first laser light (received by the luminescent material) into luminescent material light. Especially, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, like at least 90%, especially at least 95% of the first laser light (received by the luminescent material) into luminescent material light. Furthermore, the luminescent material may especially be configured to convert at least part of the first laser light into luminescent material light, such that at least part of the luminescent material light may propagate (via the first optical element) to the second optical element. Especially, in embodiments, at least at least 50%, such as at least 60%, like at least 70% of the (converted) luminescent material light may propagate from the luminescent material (via the first optical element) to the second optical element. More especially, at least 80%, like at least 90%, especially at least 95% of the (converted) luminescent material light may propagate from the luminescent material (via the first optical element) to the second optical element.

[0022] The phrase “to convert at least part of the laser light received by the luminescent material into luminescent material light”, and similar phrases, may thus indicate that when at least part of laser light indeed irradiates the luminescent material (in an operational mode of the light generating system), then at least part of that laser light may be converted into luminescent material light. Especially, the luminescent material may be configured in the reflective mode relative to laser light irradiating the luminescent material. 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. A thermally conductive element may especially comprise thermally conductive material. A thermally conductive material may especially have a thermal conductivity of at least about 20 W / (m*K), like at least about 30 W / (m*K), such as at least about 100 W / (m*K), like especially at least about 200 W / (m*K). In yet further specific embodiments, a thermally conductive material may especially have a thermal conductivity of at least about 10 W / (m*K). In embodiments, the thermally conductive material may comprise one or more of copper, aluminum, silver, gold, silicon carbide, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, a silicon carbide composite, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, diamond, and graphite. Alternatively, or additionally, the thermally conductive material may comprise or consist of aluminum oxide. In embodiments, the thermally conductive element may comprise (or be configured in thermal contact with) one or more of a heatsink, a heat spreader, and a two-phase cooling device. An element may be considered in “thermal contact” with another element if it can exchange energy through the process of heat. Hence, the elements may be thermally coupled. In embodiments, thermal contact can be achieved by physical contact. In embodiments, thermal contact may be achieved via a thermally conductive material, such as a thermally conductive glue (or thermally conductive adhesive). Thermal contact may also be achieved between two elements when the two elements are arranged relative to each other at a distance of equal to or less than about 10 pm, though larger distances, such as up to 100 pm may be possible. The shorter the distance, the better the thermal contact. Especially, the distance is 10 pm or less, such as 5 pm or less, such as 1 pm or less. The distance may be the distanced between two respective surfaces of the respective elements. The distance may be an average distance. For instance, the two elements may be in physical contact at one or more, such as a plurality of positions, but at one or more, especially a plurality of other positions, the elements are not in physical contact (e.g. when one or both elements have a rough surface). Hence, in embodiments in average the distance between the two elements may be 10 pm or less (though larger average distances may be possible, such as up to 100 pm). When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum. When an intermediate material is available, the larger the distance, the higher the thermal conductivity may be useful for thermal contact between the two elements. However, the smaller the distance, the lower the thermal conductivity of the intermediate material may be (of course, higher thermal conductive materials may also be used).

[0023] Herein, when an element is indicated to be operated in a reflective mode this may in embodiments imply that at one or more wavelengths the part of the radiation that is reflected may be larger than the part of the radiation that is transmitted or absorbed. Hence, in embodiments, when an element is indicated to be operated in the reflective mode this may in embodiments imply that at one or more wavelengths more than 50% of the radiation is reflected (rather than being transmitted or absorbed) Here, the percentage refers to the percentage of the radiant flux of the radiation incident on the element (that is operated in the reflective mode). Additionally or alternatively, in embodiments, the luminescent material may be configured in the transmissive mode relative to laser light irradiating the luminescent material. 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. Herein, when an element is indicated to be operated in a transmissive mode this may, in embodiments, imply that at one or more wavelengths the part of the radiation that is transmitted may be larger than the part of the radiation that is reflected or absorbed. Hence, in embodiments, when an element is indicated to be operated in the transmissive mode this may in embodiments imply that at one or more wavelengths more than 50% of the radiation is transmitted (rather than being reflected or absorbed) Here, the percentage refers to the percentage of the radiant flux of the radiation incident on the element (that is operated in the transmissive mode).

[0024] Similarly to the luminescent material, in embodiments, the diffuser element may (also) be configured in either the reflective mode or the transmissive mode. Especially, in embodiments, the luminescent material and the diffuser element may individually be configured in either the reflective mode or the transmissive mode. Herein, in specific embodiments, the luminescent material may be configured in the reflective mode and the diffuser element may be configured in the transmissive mode.

[0025] Returning to the luminescent material, in embodiments, the luminescent material may especially be configured to convert the (blue) first laser light into luminescent material light having a wavelength in the yellow-green wavelength range. Additionally or alternatively, in embodiments, the luminescent material may be configured to convert the (blue) first laser light into luminescent material light having a wavelength in the red wavelength range. Embodiments and features of the luminescent material and the luminescent material light are described further below.

[0026] As described above the luminescent material light may, in embodiments, propagate via the first optical element to the second optical element. The first optical element may thus, in embodiments, be configured in a light-receiving relationship with the luminescent material. Especially, the first optical element may be configured to at least partially reflect the luminescent material light (received by the first optical element). Additionally or alternatively, the first optical element may be configured to at least partially transmit the luminescent material light (received by the first optical element). In embodiments, the luminescent material light at least partially transmitted and / or reflected by the first optical element may propagate to the second optical element. In specific embodiments, the first optical element may be configured to at least partially (or even fully) transmit the first laser light (received by the first optical element) and to at least partially (or even fully) reflect the luminescent material light (received by the first optical element). In alternative specific embodiments, the first optical element may be configured to at least partially (or even fully) reflect the first laser light (received by the first optical element) and to at least partially (or even fully) transmit the luminescent material light (received by the first optical element). Especially, in embodiments, the first optical element may be configured to transmit or reflect >10%, such as >15%, like >25%, especially >50%, more especially >75% of the first laser light (received by the first optical element). More especially, in such embodiments, the first optical element may be configured to transmit or reflect <100%, such as <90%, like <85%, especially <75% of the first laser light (received by the first optical element). Further, in embodiments, the first optical element may be configured to reflect or transmit >10%, such as >15%, like >25%, especially >50% of the luminescent material light (received by the first optical element). More especially, in such embodiments, the first optical element may be configured to transmit or reflect <100%, such as <90%, like <85%, especially <75% of the luminescent material light (received by the first optical element). The first optical element may especially, in embodiments, be configured either (i) to substantially transmit the (blue) device light (received by the first optical element) and to substantially reflect the (yellow) luminescent material light (received by the first optical element) or (ii) to substantially reflect the (blue) device light (received by the first optical element) and to substantially transmit the (yellow) luminescent material light (received by the first optical element). Therefore, in embodiments, the first optical element may comprise at least a dichroic beam splitter, see also further below.

[0027] Referring back to the second laser light source, in embodiments, the diffuser element may be configured downstream of the second laser light source. The diffuser element may thus, in embodiments, be configured in a light-receiving relationship with the second laser light source. Especially, the diffuser element may be configured to transmit (and diffuse) at least part of the second laser light (received by the diffuser element). More especially, in embodiments, the diffuser element may be configured to transmit and scatter the second laser light, therewith providing diffused laser light. In embodiments, the second laser light transmitted and diffused by the diffuser element (i.e. , the diffused laser light) may propagate to the second optical element.

[0028] As indicated above, the second optical element may thus be configured downstream of both the first optical element and the diffuser element. In embodiments, the luminescent material light may propagate to the second optical element (via the first optical element) and the diffused laser light may propagate to the second optical element (via the diffuser element). The second optical element may, in embodiments, be configured to combine at least part of the luminescent material light and at least part of the diffused laser light. Especially, in embodiments, the second optical element may be configured to combine at least part of the luminescent material light and at least part of the diffused laser light into a same optical path. Hence, the light propagating from the second optical element may comprise luminescent material light and diffused device light propagating along the same optical path. Therefore, in embodiments, the second optical element may comprise one or more of a collimator, a beam homogenizer, a beam combiner, and integrator and a beam splitter (such as a dichroic or polarizing beam splitter, see also further below).

[0029] 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, especially the first optical element, the second optical element and further optical element (see further below), may include one or more of mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, arrays of one or more of the afore-mentioned, etc. Alternatively or additionally, the term “optics” may refer to a holographic element or a mixing rod. In embodiments, the optics may include one or more of beam expander optics and zoom lens optics. In embodiments, the optics may comprise an integrator, like a “Koehler integrator” (or “Kohler integrator”). Note that a dichroic beam splitter or a polarizing beam splitter can also be used as beam combiners.

[0030] In embodiments, the luminescent material light and the diffused device light may thus be provided along the same optical path by the light generating system (using the second optical element). If, in embodiments, the luminescent material light and the diffused device light are provided along different optical paths (especially orthogonal (or perpendicular) optical paths relative to each other) the optics may further comprise one or more optical elements, such as e.g. reflectors, configured to (re-)direct one or both of the luminescent material light and the diffused device light, such that the luminescent material light and the diffused device light may be provided along the same optical path. The light generating system may especially be configured to generate system light. In embodiments, the system light may comprise at least part of the luminescent material light and at least part of the diffused laser light. In specific embodiments, the system light may essentially consist of the luminescent material light and the diffused device light as provided along the same optical path by the second optical element. Herein, the phrase “the luminescent material light and the diffused device light are provided along the same optical path” and similar phrases may refer to the respective beams of light being provided such, that their respective optical axes may be substantially parallel and / or may coincide. The term “optical axis” may especially be defined as an imaginary line that defines the path along which light propagates through a system. Especially, the optical axis may coincide with the direction of the light with the highest radiant flux.

[0031] In embodiments, the light generating system may further comprise lenses. The lenses may comprise a (first) lens upstream from the diffuser element and a (second) lens downstream from the diffuser element. The (first) lens upstream from the diffuser element may be configured to focus a beam of (the first part of the) second laser light having a first width, Wl, onto the diffuser element, the (second) lens downstream from the diffuser element is configured to collimate the diffused laser light into a beam having a second width, W2. In embodiments, the second width W2 may be larger than the first width Wl, i.e., the beam of light has been diffused and / or scattered. The beam width may be expressed in full- width-half-max (FWHM). The difference in beam width may be at least 20 degrees or at least 40 degrees (FWHM). Wl may be less than 60 degrees or less than 40 degrees. W2 may be at least 80 degrees or at least 100 degrees. The obtained effect is improving the (eye-)safety of the light generating system. The reason is that the blue laser light is substantially diffused.

[0032] As described above, the second laser light may be blue light. Hence, the diffused laser light may as a result also be blue light. Furthermore, the luminescent material light may comprise yellow-green light. Hence, in embodiments, the system light (comprising at least part of the luminescent material light and at least part of the diffused laser light) may be white light. Especially, in embodiments, the system light may be white light having a correlated color temperature selected from the range of 2700-9000 K and a color rendering index (CRI) of at least 60, such as at least about 65, like in embodiments at least about 70.

[0033] 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, such as from the range of 6500-9000 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.

[0034] In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, like at least 8000 K. Yet further, in embodiments the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 65, especially at least 70. More especially, in embodiments, the system light may be white light having a CRI of at least 80. Hence, such white system light may be especially applicable for use in the beams of light for e.g. automotive lighting.

[0035] The light generating system may further 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.

[0036] In embodiments, the optics may further comprise a third optical element. Further, in embodiments, the optics may comprise a fourth optical element. In specific embodiments, the optics may comprise the third and the fourth optical element.

[0037] The third optical element may be configured between the second laser light source and the diffuser element. Especially, in embodiments, the third optical element may be configured downstream of the second laser light source. As such the third optical element may be configured in a light-receiving relationship with the second laser light source. In embodiments, the third optical element may be configured to partially transmit and partially reflect the second laser light (received by the third optical element). Especially, in embodiments, the third optical element may be configured to partially transmit the second laser light (received by the third optical element) such that a first part of the second laser light may propagate to the diffuser element. Additionally, in embodiments, the third optical element may be configured to partially reflect the second laser light (received by the third optical element) such that a second part of the second laser light may propagate to the fourth optical element. However, alternatively, in embodiments, the third optical element may be configured (i) to partially reflect the second laser light (received by the third optical element) such that a first part of the second laser light may propagate to the diffuser element and (ii) to partially transmit the second laser light (received by the third optical element) such that a second part of the second laser light may propagate to the fourth optical element.

[0038] In embodiments, the third optical element may be configured such that at least 30% of the second laser light (received by the third optical element) may propagate to the diffuser element, such as at least 40%, like at least 50%, especially at least 60%, more especially at least 70%. Similarly, in embodiments, the third optical element may be configured such that at least 30% of the second laser light (received by the third optical element) may propagate to the diffuser element, such as at least 40%, like at least 50%, especially at least 60%, more especially at least 70%. Especially, in embodiments, the third optical element may be configured such that more second laser light (received by the third optical element) may propagate to the fourth optical element than to the diffuser element. For example, in embodiments, the third optical element may be configured such that at most 40% of the second laser light (received by the third optical element) may propagate to the diffuser element and at least 60% of the second laser light (received by the third optical element) may propagate to the fourth optical element, such as that 30% of the second laser light (received by the third optical element) may propagate to the diffuser element and 70% of the second laser light (received by the third optical element) may propagate to the fourth optical element, like that 20% of the second laser light (received by the third optical element) may propagate to the diffuser element and 80% of the second laser light (received by the third optical element) may propagate to the fourth optical element.

[0039] In embodiments, the fourth optical element may be configured between the first laser light source and the first optical element. Especially, in embodiments, the fourth optical element may be configured downstream of the first laser light source and the second laser light source. As such the fourth optical element may be configured in a light-receiving relationship with the first laser light source and (the second part of the second laser light from) the second laser light source (emitted via the third optical element). The fourth optical element may especially be configured to combine the first laser light (received from the first laser light source) and the second part of the second laser light (received from the second laser light source via the third optical element) into combined laser light. Additionally, in embodiments, the fourth optical element may be configured to (re)direct the combined laser light (received by the fourth optical element) to the first optical element. Hence, in embodiments, the fourth optical element may be configured to (re)direct the combined laser light (received by the fourth optical element) in the same optical path and propagating to the first optical element.

[0040] In some embodiments, the first optical element may be configured to at least partially transmit the combined laser light (received by the first optical element). Especially, the first optical element may be configured to at least partially transmit the combined laser light (received by the first optical element), such that it may propagate to the luminescent material. The luminescent material may then, in embodiments, be configured to convert at least part of the combined laser light (received by the luminescent material) into luminescent material light. The luminescent material may especially be configured in the reflective mode, such that the luminescent material light may propagate (back) to the first optical element. In such embodiments, the first optical element may be configured to reflect the luminescent material light (received by the first optical element). Especially, in embodiments, the first optical element may be configured to reflect the luminescent material light (received by the first optical element), such that at least part of the luminescent material light may propagate (from the luminescent material) to the second optical element.

[0041] In alternative embodiments, the first optical element may be configured to at least partially reflect the combined laser light (received by the first optical element). Especially, the first optical element may be configured to at least partially reflect the combined laser light (received by the first optical element), such that it may propagate to the luminescent material. The luminescent material may then, in embodiments, be configured to convert at least part of the combined laser light (received by the luminescent material) into luminescent material light. The luminescent material may especially be configured in the reflective mode, such that the luminescent material light (provided by the luminescent material) may propagate (back) to the first optical element. In such embodiments, the first optical element may be configured to transmit the luminescent material light (received by the first optical element). Especially, in embodiments, the first optical element may be configured to transmit the luminescent material light (received by the first optical element), such that at least part of the luminescent material light may propagate (from the luminescent material) to the second optical element. Hence, in embodiments, the luminescent material may be configured to convert at least 50%, such as at least 60%, like at least 70%, especially at least 80%, like at least 90%, especially at least 95% of the combined laser light (received by the luminescent material) into luminescent material light. Furthermore, the luminescent material may especially be configured to convert at least part of the combined laser light (received by the luminescent material) into luminescent material light, such that at least part of the luminescent material light may propagate (via the first optical element) to the second optical element. Especially, in embodiments, at least at least 50%, such as at least 60%, like at least 70%, especially at least 80%, like at least 90%, especially at least 95% of the (converted) luminescent material light may propagate from the luminescent material (via the first optical element) to the second optical element.

[0042] Here, in embodiments, the diffuser element may be configured downstream of (both the second laser light source and) the third optical element. Especially, in embodiments, the diffuser element may be configured in a light-receiving relationship with the third optical element. As such, in embodiments, the diffuser element may be configured to receive the first part of the second laser light (from the second laser light source via the third optical element). The diffuser element may especially be configured in the transmissive mode. As such, in embodiments, the diffuser element may be configured to transmit (and diffuse) (the first part of) the second laser light such that (transmitted) diffused laser light may propagate (from the diffuser element) to the second optical element.

[0043] Note that, alternatively, in embodiments, the diffuser element can also be configured in the reflective mode, such that the diffuser element may be configured to reflect (and diffuse) (the first part ol) the second laser light such that (reflected) diffused laser light may propagate (from the diffuser element) to the second optical element. In such embodiments, the diffuser may especially comprise a polarization maintaining diffuser. Furthermore, in such embodiments, the light generating system may comprise a birefringent rotator, such as e.g. a X / 4 waveplate. In embodiments, the birefringent rotator may be configured downstream of the second laser light source and upstream of the diffuser. Especially, in embodiments, the birefringent rotator may be configured (i) to convert (first) linearly polarized light (received by the birefringent rotator) into (first) circularly polarized light and (ii) to convert (second) circularly polarized light (received by the birefringent rotator) into (second) linearly polarized light. However, in specific embodiments, the optics may further comprise a third optical element, and a fourth optical element, wherein: (A) the third optical element is configured between the second laser light source and the diffuser element, wherein the third optical element is configured downstream of the second laser light source, and wherein the third optical element is configured to partially transmit and partially reflect the second laser light such that a first part of the second laser light propagates to the diffuser element and a second part of the second laser light propagates to the fourth optical element; (B) the fourth optical element is configured between the first laser light source and the first optical element, wherein the fourth optical element is configured downstream of the first laser light source and (the second part of the second laser light from) the second laser light source (emitted via the third optical element), and wherein the fourth optical element is configured to combine the first laser light and the second part of the second laser light into combined laser light, and to direct the combined laser light to the first optical element; and wherein one of the following applies: (i) the first optical element is configured to at least partially transmit the combined laser light, wherein the luminescent material is configured to convert at least part of the combined laser light into luminescent material light, wherein the first optical element is configured to reflect the luminescent material light such that at least part of the luminescent material light propagates (from the luminescent material) to the second optical element; (ii) the first optical element is configured to at least partially reflect the combined laser light, wherein the luminescent material is configured to convert at least part of the combined laser light into luminescent material light, wherein the first optical element is configured to transmit the luminescent material light such that at least part of the luminescent material light propagates (from the luminescent material) to the second optical element; and (C) the diffuser element is configured downstream of the third optical element, wherein the diffuser element is configured to receive the first part of the second laser light (from the second laser light source via the third optical element), and wherein the diffuser element is configured to transmit the second laser light such that (transmitted) diffused laser light propagates to the second optical element. In this way, a light generating system may be provided in which one blue laser light source is used for both light conversion and light scattering. Furthermore, in this way, both blue laser light polarizations may be used, and therewith the efficiency of the light generating system may be increased.

[0044] In embodiments, the first optical element may thus be configured to receive and (re)direct different types of light (especially laser light and luminescent material light). Therefore, in embodiments, the first optical element may comprise at least a beam splitting functionality. In embodiments, the first optical element may comprise a dichroic beam splitter. Additionally or alternatively, in embodiments, the first optical element may comprise a polarizing beam splitter. In specific embodiments, the first optical element may comprise a combination of a polarizing beam splitter and a dichroic beam splitter. In general, a polarizing beam splitter is configured to split a beam of light in dependence of its polarization, i.e., light having one polarization may be transmitted and light having another (orthogonal) polarization may be reflected by the beam splitter. Conversely, a dichroic beam splitter is configured to split a beam of light in dependence of its wavelength, i.e., light having one wavelength may be transmitted and light having another (different) wavelength may be reflected by the beam splitter. Here, in embodiments, the first optical element may comprise at least a dichroic beam splitter configured to either transmit or reflect blue laser light and to either reflect or transmit yellow-green luminescent material light.

[0045] The luminescent material light may thus have a (centroid) wavelength different from the peak wavelengths of the first and / or second laser light sources. In embodiments, the luminescent material is configured to convert at least part of first radiation (selected from one or more of UV radiation and visible radiation), into luminescent material light. Especially, in embodiments the luminescent material may be configured to convert at least part of blue light (as radiation) into luminescent material light. Especially when blue light is partly converted, the blue light may be used as source of blue light (for the device light) and as excitation light that can be converted by the luminescent material. The first radiation may especially be provided by a (solid state) light source, such as the first laser light source and / or the second laser light source.

[0046] 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.

[0047] In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation of a smaller wavelength is converted into radiation with a larger wavelength (Xex<Xem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation of a larger wavelength is converted into radiation with a smaller wavelength (Xex>Xem).

[0048] In embodiments, the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and / or fluorescence.

[0049] The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. 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.

[0050] 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.

[0051] 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.

[0052] 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 at least a first (garnet) luminescent material of the type A3B5O12: Ce3+(also indicated as A3BsOi2:Ce3+), 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%.

[0053] 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.

[0054] Hence, in specific embodiments the luminescent material comprises at least a first luminescent material of the type AsBsOnT'e. wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc, and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi-xLux)3BsOi2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi-xLux)3AlsOi2:Ce, part ofY and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0055] In embodiments, the luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-0 may be replaced by Si-N.

[0056] In specific embodiments the luminescent material comprises (Yxi-x2- x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y 2=1, wherein 0<y2<0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially xl>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions.

[0057] 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 (YX1-X2- x3(Lu,Gd)x2Cex3)3(Alyi-y2Gay2)5Oi2, wherein Lu and / or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3<0.1, and wherein 0<y2<0.1. Further, in specific embodiments, at maximum 1% of B-0 may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yxi-x3Cex3)3AlsOi2, wherein xl+x3=l, and wherein 0<x3<0.2, such as 0.001-0.1.

[0058] In specific embodiments, the luminescent material may only include luminescent materials selected from the type of cerium comprising garnets. In even further specific embodiments, the luminescent material includes a single type of luminescent materials, such as (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Hence, in specific embodiments the luminescent material comprises a luminescent material, wherein at least 85 weight%, even more especially at least about 90 wt.%, such as yet even more especially at least about 95 weight % of the luminescent material comprises (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Here, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y 2=1, wherein 0<y2<0.2. Especially, x3 is selected from the range of 0.001-0.1. Note that in embodiments x2=0. Alternatively or additionally, in embodiments y2=0. In specific embodiments, A may especially comprise at least Y, and B may especially comprise at least Al.

[0059] Alternatively or additionally, the luminescent material may comprise a luminescent material of the type AsSieNi i:Ce3. wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.

[0060] In specific embodiments, the luminescent material may comprise at least two different luminescent materials configured to provide luminescent material light having different spectral power distributions. As can be derived from the above, the term “different luminescent materials” may refer to luminescent materials that are different, or to two compositions, each including at least one luminescent material in common, but wherein the compositions differ. For instance, a primary luminescent material comprising luminescent materials A and B, and a secondary luminescent material comprising only A or only B, or comprising both A and B, but in a different weight ratio. Such primary luminescent material and secondary luminescent material may have different spectral power distributions of their respective luminescent material light.

[0061] The garnet type luminescent material may also be described with an alternative formula A3B’2C”30i2. Here, A may comprise one or more of (i) rare earth ions, such as one or more selected from Y3+, Lu3+, Gd3+, Tb3+, La3+, and (ii) divalent cations, such as Ca2+. Here, B may comprise one or more of (i) trivalent cations, such as one or more of Al3+, Ga3+, Sc3+, Sb3+, and In3+, and (ii) divalent cations, such as one or more of Mg2+and Mn2+. Here, C may comprise one or more of (i) trivalent cations, such as one or more of Ga3+and Al3+, (ii) divalent cations, such as Mn2+, and (iii) tetravalent cations, such as one or more of Si4+and Ge4+. With such ions, the garnet crystal structure can be maintained. Other substitutions than mentioned may also be possible.

[0062] In embodiments, the luminescent material may alternatively or additionally comprise one or more of MS:Eu2+and / or I LSisb- Eu2and / or MAlSiN3:Eu2+and / or Ca2AlSi3O2Ns:Eu2+, etc., wherein M comprises one or more of Ba, Sr and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSiN3:Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba. The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as M2SisN8:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and / or Ba. In a further specific embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSis Eu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca). Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSiN3:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art. Hence, such nitride luminescent materials may also be or comprise converter elements, here especially Eu2+.

[0063] 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.

[0064] In embodiments, a red luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSiN3:Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3. Divalent europium will in general replace divalent cations, such as the above divalent alkaline earth cations, especially Ca, Sr or Ba.

[0065] The material (Ba,Sr,Ca)S:Eu can also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca).

[0066] Further, the material (Ba,Sr,Ca)2SisN8:Eu can also be indicated as M2SisN8:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound Sr and / or Ba. In a further specific embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), especially 50 to 100%, more especially 50 to 90% Ba and 50 to 0%, especially 50 to 10% Sr, such as Bai.sSro.sSis Eu (i.e. 75 % Ba; 25% Sr). Here, Eu is introduced and replaces at least part of M, i.e. one or more of Ba, Sr, and Ca).

[0067] Likewise, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSiN3:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); especially, M comprises in this compound calcium or strontium, or calcium and strontium, more especially calcium. Here, Eu is introduced and replaces at least part of M (i.e. one or more of Ba, Sr, and Ca). Eu in the above indicated luminescent materials is substantially or only in the divalent state, as is known to the person skilled in the art.

[0068] Blue luminescent materials may comprise YSO (Y 2SiOs:Ce3+), or similar compounds, or BAM (BaMgAlioOi?:Eu2+), or similar compounds.

[0069] Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc.. Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used. Quantum dots show very narrow emission band and thus they show saturated colors. Furthermore the emission color can easily be tuned by adapting the size of the quantum dots. Any type of quantum dot known in the art may be used in the present invention. However, it may be preferred for reasons of environmental safety and concern to use cadmium-free quantum dots or at least quantum dots having a very low cadmium content. 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] Organic phosphors can be used as well. Examples of suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, for example compounds sold under the name Lumogen® by BASF. Examples of suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170.

[0071] Different luminescent materials may have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials may especially have different color points (or dominant wavelengths). As indicated above, other luminescent materials may also be possible. Hence, in specific embodiments the luminescent material is selected from the group of divalent europium containing nitrides, divalent europium containing oxynitrides, divalent europium containing silicates, cerium comprising garnets, and quantum structures. Quantum structures may e.g. comprise quantum dots or quantum rods (or other quantum type particles) (see above). Quantum structures may also comprise quantum wells. Quantum structures may also comprise photonic crystals.

[0072] The luminescent material may be comprised by a luminescent body. The luminescent body may be a layer, like a self-supporting layer. The luminescent body may also be a coating. The luminescent body may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode). Especially, the luminescent body may essentially be self-supporting. In embodiments, the luminescent material may be provided as luminescent body, such as a luminescent single crystal, a luminescent glass, or a luminescent ceramic body. Such body may be indicated as “converter body” or “luminescent body”. In embodiments, the luminescent body may be a luminescent single crystal or a luminescent ceramic body. For instance, in embodiments a cerium comprising garnet luminescent material may be provided as a luminescent single crystal or as a luminescent ceramic body. In other embodiments, the luminescent body may comprise a light transmissive body, wherein the luminescent material is embedded. For instance, the luminescent body may comprise a glass body, with luminescent material embedded therein. Or, the glass as such may be luminescent. In other embodiments, the luminescent body may comprise a polymeric body, with luminescent material embedded therein.

[0073] In specific embodiments, the luminescent body comprises a ceramic body comprising the luminescent material. Ceramic bodies are known in the art. Alternatively, the luminescent body comprises single crystal. In yet further specific embodiments, different types of luminescent bodies may be applied. Hence, the body may especially be selected from single crystalline bodies and ceramic bodies. The latter may be more easily made than the former, while they nevertheless may have good optical and / or thermal properties. Hence, in embodiments the body may be a ceramic body. However, in specific embodiments also a combination of single crystalline bodies and ceramic bodies may be applied. Especially, the luminescent body comprises a ceramic luminescent body. Hence, in specific embodiments the luminescent body is defined by a ceramic luminescent material. Therefore, in specific embodiments the luminescent material is a luminescent material that can be provided a ceramic luminescent body. Hence, the luminescent body may comprise a ceramic luminescent body.

[0074] The luminescent body may have any shape. In general, however, the luminescent body may comprise two essentially parallel faces, defining a height (of the luminescent body). Further, the luminescent body may comprise an edge face, bridging the two essentially parallel faces. The edge face may be curved in one or two dimensions. The edge face may be planar. The luminescent body may have a rectangular or circular crosssection, though other cross-sections may also be possible, like e.g. hexagonal, octagonal, etc. Hence, the luminescent body may have a circular cross-section, an oval cross-section, square, or non-square rectangular. In embodiments, the luminescent body may have an n-gonal crosssection, wherein n is at least 3, like 4 (square or rectangular cross-section), 5 (pentagonal cross-section), 6 (hexagonal cross-section), 8 (octagonal cross-section) or higher. The two essentially parallel faces may also be indicated as “main faces”, as they may especially provide the largest external area of the luminescent body. Perpendicular to the aforementioned cross-section, may be another cross-section, which may in embodiments be rectangular. Hence, the luminescent body may e.g. have a cubic shape, a (non-cubic) cuboid shape, an n-gonal prism shape with n being at least 5 (such as pentagonal prism, hexagonal prism), and a cylindrical shape. Other shapes, however, may also be possible. Especially, the luminescent body may have a cuboid shape, a cylindrical shape, or an n-gonal prism shape wherein n is 6 or 8. In the case of a cylindrical shape, the edge face may be a single edge face. In the case of a cuboid, the edge face may comprise four facets. In the case of a hexagonal prism the edge face may comprise six facets.

[0075] The light generating system may further, in embodiments, comprise a radiance enhancement film configured downstream from the luminescent material. In embodiments, the radiance enhancement film may essentially be a coating configured over (and upstream of) the luminescent material. Especially, in embodiments, the radiance enhancement film may be configured to receive the luminescent material light emitted from the luminescent material. Further, in embodiments, the radiance enhancement film may be configured to transmit laser light (received by the radiance enhancement film) and / or luminescent material light (received by the radiance enhancement film). In embodiments, a radiance enhancement film may be, e.g., a diffractive optical element, (such as that manufactured by Heptagon located in Zurich, Switzerland), or a micro refractive element or Brightness Enhancement Film (such as that manufactured by 3M).

[0076] Additionally or alternatively, in embodiments, the light generating system may comprise a polarization recovery component. In embodiments, the polarization recovery component may essentially be a coating configured over (and upstream ol) the luminescent material. Especially, in embodiments, the polarization recovery component may be configured to receive the luminescent material emitted from the luminescent material. Further, in embodiments, the polarization recovery component may be configured to transmit laser light (received by the polarization recovery component) and / or luminescent material light (received by the polarization recovery component). In embodiments, the polarization recovery component, may sometimes be referred to as a non-absorbing polarizer (such as that manufactured by Moxtek, Inc. located in Orem Utah), or as a Dual Brightness Enhancement Film (such as that manufactured by 3M).

[0077] A position or arrangement or configuration upstream of the luminescent material may especially indicate embodiments wherein light that will excite the luminescent material may propagate via that upstream position or arrangement or configuration. This may thus include positions or arrangements or configurations via which luminescent material light may propagate. In embodiments, the radiance enhancement film and / or the polarization recovery component may be configured mounted (or coated) onto the luminescent body. However, in other embodiments, the radiance enhancement film and / or the polarization recovery component may be configured remote from the luminescent body. In embodiments, the radiance enhancement film may be positioned between the luminescent material and the polarization recovery component. Alternatively, in embodiments, the relative positions of the radiance enhancement film and polarization recovery component with regard to the luminescent material may be reversed. Hence, in embodiments, the light generating system may comprise one or more of a radiance enhancement film and a polarization recovery component configured to receive the luminescent material light emitted from the luminescent material; wherein the radiance enhancement film comprises at least one of a diffractive optical element and a micro refractive element; and wherein the polarization recovery component comprises a non-absorbing polarizer. Such embodiments may be beneficial as the radiance enhancement film and the polarization recovery component may restrict the angular distribution and polarization state of the light produced by light generating system, by transmitting the desired light (luminescent material light) and reflecting the undesired light (e.g. unconverted laser light) back towards the luminescent material. Because the luminescent material has very little absorption of the light generated, the recycling efficiency is very high. Furthermore, the use of radiance enhancement films and polarization recovery components may increase the radiance and polarization, and therefore makes the system light more uniform.

[0078] As described above, in embodiments, the second optical element may be configured to combine at least part of the luminescent material light and at least part of the diffuser laser light into a same optical path. Therefore, in some embodiments, the second optical element may comprise one or more of a polarizing beam splitter, a dichroic beam splitter, a diffractive optical element, a hologram, and a semi-specular reflective mirror. Especially, in embodiments, the second optical element may comprise one or more of a dichroic mirror, a dichroic cube, and a dichroic sphere. For example, in some embodiments, the luminescent material light and the diffused laser light may be provided to the second optical element from orthogonal directions, and the second optical element may comprise a dichroic mirror configured to combine the (yellow) luminescent material light and the (blue) diffused device light into the same optical path. Additionally or alternatively, in embodiments, the second optical element may comprise one or more of a beam homogenizer, and a beam collimator. For example, in embodiments, the luminescent material light and the diffused laser light may be provided to the second optical element along the same optical path, and the second optical element may comprise a beam homogenizer configured to combine and homogenize the received light and to provide (homogenized white) system light along the same optical path. Hence, in embodiments, the second optical element may comprise (i) one or more of a polarizing beam splitter, a dichroic beam splitter, a dichroic mirror, a dichroic cube, a dichroic sphere, a diffractive optical element, a hologram, and a semi-specular-reflecting mirror, or (ii) one or more of a beam combiner, a beam homogenizer, and a beam collimator. Such embodiments may be beneficial as the second optical element may provide a relatively compact solution for providing system light comprising both the luminescent material light and the diffused laser light mixed together along the same optical path. Hence, the second optical element may be configured to combine beams of light.

[0079] The light generating system may thus be a relatively compact system comprising both a luminescent material and a diffuser element. As the light generating system comprises a luminescent material, the light generating system may generate heat. Such heat may have a negative effect on the e.g. the performance of the luminescent material. Hence, in embodiments, the light generating system may comprise a rotating element comprising one or more of the luminescent material and the diffuser element. Especially, the rotating element may e.g. comprise one of the group comprising as a phosphor wheel and a phosphor rod. The rotating element may, in embodiments, comprise one or more of the luminescent material and the diffuser element. Especially, the rotating element may be configured to support the luminescent material. Additionally, in embodiments, the rotating element may be configured to support the diffuser element. In embodiments, the light generating system may comprise one or more rotating elements. For example, in embodiments, the light generating system may comprise a rotating element configured to support the luminescent material and a (different) rotating element configured to support the diffuser element. However, in some embodiments (see also Figs. 2 below), the luminescent material and the diffuser element may be supported by the same rotating element.

[0080] Further, in embodiments, the rotating element may comprise a thermally conductive material, i.e., may comprise a heat sink or may thermally conduct heat to a heat sink. Hence, the luminescent material, e.g. configured on a phosphor wheel, may be configured in thermal contact with the thermally conductive material. However, in embodiments without a phosphor wheel, also a thermally conductive material, may be configured in thermal contact with the luminescent material. For instance, in embodiments the luminescent material may be configured in physical contact with the thermally conductive material.

[0081] Embodiments of the light generating system comprising such a rotating element as described herein may be beneficial as the luminescent material (and / or the diffuser element) may be rotated providing sections of the luminescent material (and / or the diffuser element) with alternating periods of illumination and periods of cooling.

[0082] In specific embodiments, the rotating element may comprise a phosphor wheel comprising one or more (concentric) rings. Especially, in embodiments, the one or more rings may comprise a first ring comprising the luminescent material and a second ring comprising the diffuser element. Additionally or alternatively, in embodiments, at least one of the one or more rings may comprise sections. Especially, in such embodiments, the at least one of the one or more rings may comprise a luminescent material section comprising the luminescent material and a diffuser section comprising the diffuser element. For example, in embodiments, the phosphor wheel may comprise two concentric rings, a first ring comprising the luminescent material and a second ring comprising the diffuser element. In an alternative example, in embodiments, the phosphor wheel may comprise two concentric rings, a first ring essentially consisting of luminescent material and a second ring comprising a luminescent material comprising section and a diffuser element comprising section. Hence, in embodiments, the rotating element may be configured to support a ring comprising the luminescent material and / or the diffuser element.

[0083] In embodiments, the rotating element, especially the phosphor wheel, may comprise a plurality of (concentric) rings. Especially, in embodiments, the rotating element, especially the phosphor wheel, may comprise at least one, such as a plurality of, rings comprising the luminescent material and at least one, such as a plurality of, rings comprising the diffuser element.

[0084] In embodiments, as indicated above, the diffuser element may be configured in the transmissive mode. The light generating system may, in embodiments, comprise a safety arrangement configured to, when the diffuser element fails, prevent direct laser light from escaping the light generating system. Therefore, in embodiments, the safety arrangement may be configured to, when the diffuser element fails, switch off the second laser light source. By switching off the second laser light source no second laser light may enter the light generating system. Additionally, or alternatively, in embodiments, the safety arrangement may be configured to, when the diffuser element fails, guide the second laser light to a beam dump. The beam dump may be configured to capture and trap the second laser light, preventing undiffused laser light from escaping the system. Hence, in embodiments, the light generating system may comprise a safety arrangement configured, when the diffuser element fails, (i) to switch off the second laser light source, and / or (ii) to guide the second laser light to a beam dump. Such solutions may increase the safety of the system comparable to using a blue laser light diffuser in the reflective mode, while less light is lost.

[0085] In specific embodiments, the diffuser element may comprise a polarization dependent diffuser and a polarization rotator. Especially, the polarization rotator may be configured between the second laser light source and the polarization dependent diffuser. In embodiments, the polarization dependent diffuser may be configured to transmit and scatter second laser light received by the diffuser element in dependence of the polarization of the second laser light. Furthermore, the polarization rotator may be configured to rotate the polarization of the light, such as e.g. rotate p-polarized light such that it becomes s-polarized light, or vice versa. In embodiments, the polarization rotator may therefore comprise a birefringent rotator, such as e.g. a half wave plate.

[0086] In embodiments, the second laser light source may be configured to provide second laser light having a first linear polarization. For example, in embodiments, the second laser light source may be configured to provide p-polarized second laser light. Additionally or alternatively, in embodiments, the second laser light source may be configured to provide s-polarized second laser light. The polarization rotator may, in such embodiments, be configured in a light-receiving relationship with the second laser light source. As such, in embodiments, the polarization rotator may be configured to convert second laser light having the first linear polarization into second laser light having a second linear polarization. In embodiments, the second linear polarization may be different from the first linear polarization. For example, in embodiments, the second linear polarization may be p- polarization and the first linear polarization may be s-polarization, or vice versa.

[0087] The safety arrangement may further, in embodiments, comprise a reflective polarizer and a beam dump. In embodiments, the reflective polarizer may be configured between the diffuser element and the second optical element. The reflective polarizer may, in embodiments, be configured to transmit (or reflect) light having the second linear polarization, such that it may propagate to the second optical element. Additionally or alternatively, in embodiments, the reflective polarizer may be configured to reflect (or transmit) light having the first polarization, such that it may propagate to the beam dump. Thus, in embodiments, if the diffuser element is present and functioning correctly, second laser light having the first linear polarization (e.g. p-polarization or s-polarization) may propagate from the second laser light source to the diffuser element, especially to the polarization rotator. In embodiments, the polarization rotator may be configured to convert the second laser light having the first linear polarization (e.g. p-polarization or s-polarization) into second laser light having the second linear polarization (e.g. s-polarization or p- polarization). The diffuser element may, in such embodiments, be configured to provide diffused laser light having the second polarization (e.g. s-polarization or p-polarization) to the reflective polarizer. At the reflective polarizer, in embodiments, the diffused laser light having the second polarization (e.g. s-polarization or p-polarization) may be transmitted towards the second optical element. However, if the diffuser element is removed or broken, i.e., not functioning correctly, second laser light having the first linear polarization (e.g. p- polarization or s-polarization) may propagate from the second laser light source (directly) to the reflective polarizer. At the reflective polarizer, in embodiments, the second laser light having the first linear polarization (e.g. p-polarization or s-polarization) may be reflected towards the beam dump, rather than propagating further to the second optical element. Hence, in embodiments, the diffuser element may comprise a polarization dependent diffuser and a polarization rotator, wherein the polarization rotator may be configured between the second laser light source and the polarization dependent diffuser, wherein the second laser light source may be configured to provide second laser light having a first linear polarization, wherein the polarization rotator may be configured to convert the second laser light having the first linear polarization into second laser light having a second linear polarization (different from the first linear polarization), wherein the safety arrangement may further comprise a reflective polarizer and a beam dump, wherein the reflective polarizer may be configured between the diffuser element and the second optical element, wherein the reflective polarizer may be configured (i) to transmit light having the second linear polarization to the second optical element and (ii) to reflect light having the first polarization to the beam dump. Such embodiments may be beneficial as direct (blue) laser light may be trapped by the beam dump rather than escape the light generating system, therewith improving the (eye-)safety of the light generating system.

[0088] Alternatively, in embodiments, the safety arrangement may comprise a laseroutput sensor configured to determine a laser-output signal. In embodiments, the laser-output signal may be correlated with the output of the second laser light emitted by the second laser light source. Additionally, in embodiments, the safety arrangement may comprise a diffused- light sensor configured to determine a diffused-light signal. In embodiments, the diffused- light signal may be correlated with the output of diffused laser light emitted by the diffuser element. Yet further, in embodiments, the safety arrangement may comprise a control system. The control system may, in embodiments, be configured to receive the laser-output signal and the diffused-light signal. Further, in embodiments, the control system may be configured to determine a safe-to-operate parameter based on the laser-output signal and the diffused- light signal. Yet further, in embodiments, the control system may be configured to control the operation of the second laser light source based on a comparison between the safe-to-operate parameter and at least one predefined threshold. The control system may thus be configured for monitoring a signal being correlated with the laser output and a signal being correlated with the amount of diffused laser light. The correlation between the signals and the laser output and / or the amount of diffused laser light may be linear, exponential, logarithmic or the like. In case it is detected on the basis of these signals that the safe-to-operate parameter falls below or exceeds the predefined threshold, the operation of the second laser light source is automatically adapted accordingly. Situations in which the second laser light source would be unsafe to operate are when the package of the light source is opened, when an optical component of the light source is removed, when diffuser element degradation or diffuser element removal occurs, when the position of any component or light generating system has moved beyond a predefined tolerance value, or when a light-guiding part, e.g. an optical fiber, is cut or damaged etc. In general, different types of sensors can be used as laser-output sensor or diffused-light sensor. In particular, in embodiments, the laser-output sensor may be formed by a laser-light photodiode adapted for receiving at least a part of the second laser light. Additionally or alternatively, in embodiments, the laser-output sensor may be formed by a laser driving current monitor adapted for monitoring the laser driving current.

[0089] Especially, in such embodiments, the laser driving current monitor may be configured to monitor the laser driving current, which is typically proportional to a laser output, apart from a threshold current. Further, in embodiments, the diffused-light sensor may be adapted to receive at least a part of the diffused laser light. In embodiments, the diffused-light sensor may e.g. be a photodiode. Hence, in embodiments, the safety arrangement may further comprise a laser-output sensor configured to determine a laser-output signal being correlated with the output of second laser light emitted by the second laser light source; a diffused-light sensor configured to determine a diffused-light signal being correlated with the output of diffused laser light emitted by the diffuser element; and a control system configured to (i) receive the laser-output signal and the diffused-light signal, (ii) determine a safe-to-operate parameter based on the laser-output signal and the diffused-light signal, and (iii) control the operation of the second laser light source based on a comparison between the safe-to-operate parameter and at least one predefined threshold. Such embodiments may be beneficial as the cooperation of the sensors with the control system may prevent direct (blue) laser light from escaping the light generating system, therewith improving the (eye-)safety of the light generating system.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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).

[0095] 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.

[0096] Alternatively, in embodiments, the safety arrangement may comprise a beam dump and a dichroic reflector. Especially, in embodiments, the dichroic reflector may be configured downstream of the second laser light source. Further, in embodiments, the beam dump may be configured in a light-receiving relationship with the dichroic reflector, such that light reflected by the dichroic reflector may propagate to the beam dump.

[0097] The dichroic reflector may have an optical axis (OR). Herein, the optical axis (OR) may be defined as an imaginary line that defines a path towards the dichroic reflector along which (diffused) laser light propagates from the diffuser element. Especially, the optical axis (OR) may be defined intersecting the center of dichroic reflector and having an angle of 45° relative to a plane defined by the dichroic reflector.

[0098] In embodiments, light incident on the dichroic reflector may have an angle (a) relative to the optical axis. The dichroic reflector may, in embodiments, be configured such that the light beams incident on the dichroic reflector substantially parallel (i.e. a=0°) to the optical axis (OR) may be reflected, whereas light beams incident on the dichroic reflector non-parallel (i.e., o#()°) to the optical axis (OR) may be transmitted. Especially, in embodiments, the dichroic reflector may be configured to reflect light (especially undiffused second laser light) beams having an angle a<3° (relative to the optical axis (OR), such as an angle a<2°, like an angle a<l°, especially an angle a=0° to the beam dump. Conversely, the dichroic reflector may be configured to transmit light (especially diffused laser light) beams having an angle (a) selected from the range of 3°<a<45°, to the second optical element (optionally via one or more reflectors). Especially, in embodiments, the dichroic reflector may be configured to transmit light beams, having an angle (a) selected from the range of 4°<a<40°, such as an angle (a) selected from the range of 5°<a<35°, like an angle (a) selected from the range of 10°<a<30°, especially an angle (a) selected from the range of 15°<a<25°, to the second optical element. Hence, in embodiments, the safety arrangement may further comprise a beam dump and a dichroic reflector, wherein the dichroic reflector may be configured downstream of the second laser light source, wherein the dichroic reflector may have an optical axis (OR), wherein light incident on the dichroic reflector (650) has an angle (a) relative to the optical axis (OR), wherein the dichroic reflector may be configured to (i) reflect light (especially undiffused second laser light) having an angle a<2° to the beam dump, and (ii) transmit light (especially diffused laser light) having an angle 3°<a<45° to the second optical element (optionally via one or more reflectors). Such embodiments may be beneficial as direct (blue) laser light may be trapped by the beam dump rather than escape the light generating system, therewith improving the (eye-)safety of the light generating system.

[0099] Alternatively, in embodiments, the safety arrangement may comprise a safety optical element (such as a reflector) configured to reflect diffused laser light to the second optical element. For example, in embodiments, the safety optical element may comprise one or more elements selected from the group comprising a reflector, a mirror, and a beam splitter. Additionally, in such embodiments, the safety arrangement may comprise the beam dump. Especially, in embodiments, the safety optical elements may (each) comprise a pinhole. In embodiments, the pinhole may be a through-hole having a diameter selected from the range of <5 mm, such as from the range of <3 mm, like from the range of <1 mm, especially from the range of <0.5 mm, more especially from the range of <0.25 mm. Further, in embodiments, the pinhole may be a through-hole having a diameter selected from the range of >0.1 mm, such as from the range of >0.15 mm, like from the range of >0.20 mm. The pinhole may, in embodiments, be configured such that (undiffused or direct) second laser light may be transmitted to the beam dump. Conversely, the safety optical element may be configured to reflect diffused laser light, such that the diffused laser light may propagate to the second optical element. Hence, in embodiments, the safety arrangement may further comprise (i) a safety optical element (such as a reflector) configured to reflect diffused laser light to the second optical element and (ii) a beam dump, wherein the safety optical elements may comprise a pinhole configured to transmit (undiffused) second laser light to the beam dump. Such embodiments may be beneficial as direct (blue) laser light may be trapped by the beam dump rather than escape the light generating system, therewith improving the (eyesafety of the light generating system.

[0100] As indicated above, the light generating system comprises a laser light source. The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs.

[0101] Further, the term “light source” may in embodiments also refer to a so-called chips-on-board (COB) light source. The term “COB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light source may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module.

[0102] The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm. Herein, the term p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.

[0103] The light source may have a light escape surface. For LED’s it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the resin. In principle, it may also be the terminal end of a fiber. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source.

[0104] 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.

[0105] The term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser, etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED).

[0106] The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, such as an LED, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise an LED with on-chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering).

[0107] In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs. In other embodiments, however, the light source may be configured to provide primary radiation and part of the primary radiation is converted into secondary radiation. Secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be indicated as luminescent material radiation. The luminescent material may in embodiments be comprised by the light source, such as an LED with a luminescent material layer or dome comprising luminescent material. Such LEDs may be indicated as phosphor converted LEDs or PC LEDs (phosphor converted LEDs). In other embodiments, the luminescent material may be configured at some distance (“remote”) from the light source, such as an LED with a luminescent material layer not in physical contact with a die of the LED. Hence, in specific embodiments the light source may be a light source that during operation emits at least light at wavelength selected from the range of 380-470 nm. However, other wavelengths may also be possible. This light may partially be used by the luminescent material.

[0108] In embodiments, the light source may comprise a luminescent material. In embodiments, the light source may comprise a PC LED. In other embodiments, the light source may comprise a direct LED (i.e. no phosphor). In embodiments, the light source may comprise a laser device, like a laser diode. In embodiments, the light source may comprise a superluminescent diode. Hence, in specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.

[0109] 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.

[0110] 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). 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.

[0111] 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.

[0112] 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.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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).

[0117] Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of cerium doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium doped chrysoberyl (alexandrite) laser, chromium ZnSe (CrZnSe) laser, divalent samarium doped calcium fluoride (Sm:CaF2) laser, Er:YAG laser, erbium doped and erbium-ytterbium codoped glass lasers, F-Center laser, holmium YAG (Ho:YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium doped yttrium calcium oxoborate Nd:YCa4O(BO3)s or Nd:YCOB, neodymium doped yttrium orthovanadate (Nd:YVO4) laser, neodymium glass (Nd:glass) laser, neodymium YLF (Nd:YLF) solid-state laser, promethium 147 doped phosphate glass (147Pm3+:glass) solid-state laser, ruby laser (AhO3:Cr3+), thulium YAG (Tm:YAG) laser, titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser, trivalent uranium doped calcium fluoride (U:CaF2) solid-state laser, Ytterbium doped glass laser (rod, plate / chip, and fiber), Ytterbium YAG (Yb:YAG) laser, Yb2Os (glass or ceramics) laser, etc.

[0118] For instance, including second and third harmonic generation embodiments, the light source may comprise one or more of an F center laser, an yttrium orthovanadate (Nd:YVO4) laser, a promethium 147 doped phosphate glass (147Pm3+: glass), and a titanium sapphire (Ti:sapphire; AhO3:Ti3+) laser. For instance, considering second and third harmonic generation, such light sources may be used to generated blue light.

[0119] 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.

[0120] 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.

[0121] 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. 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.

[0122] 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.

[0123] 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).

[0124] 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. 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.

[0125] 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 source may comprise one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.

[0126] 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.

[0127] 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.

[0128] 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. Superluminescent diodes are e.g. described in US2020192017, incorporated herein by reference, or in “Edge Emitting Laser Diodes and Superluminescent Diodes”, Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Najda, Thomas Slight, Piotr Perlin, Book Editor(s): Fabrizio Roccaforte, Mike Leszczynski, First published: 03 August 2020 https: / / doi.org / 10.1002 / 9783527825264.ch9 in chapter 9,3 superluminescent diodes. This book, and especially chapter 9.3, are herein incorporated by reference. Superluminescent diodes may combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of the source has advantages that the speckle is significantly reduced or not visible, and the spectral distribution of emission is much broader compared to laser diodes, which can be better suited for lighting applications. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode. Especially, in embodiments the light source is configured to generate device light. In specific embodiments, the device light may be blue light. The terms “blue light” or “blue emission”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm (including some violet and cyan hues). However, intensity at shorter wavelengths may also be possible, such as within the wavelength range of 400-440 nm. In specific embodiments, the device light may have a centroid wavelength (Xci) selected from the 400-490 nm wavelength range, more especially from the 400-480 nm wavelength range. Especially, in embodiments the device light has a peak wavelength selected from the blue wavelength range.

[0129] 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, though in specific embodiments other wavelengths may also be possible. 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.

[0130] 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.

[0131] 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). The terms “green light” or “green emission”, and similar terms, may especially relate to light having a wavelength in the range of about 490-560 nm. The terms “yellow light” or “yellow emission”, and similar terms, may especially relate to light having a wavelength in the range of about 560-590 nm. The terms “red light” or “red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 620- 750 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 laser light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

[0132] In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. etc... The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the first laser light source, the second laser light source, the optics, the luminescent material, and the diffuser element.

[0133] 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.

[0134] The lighting device may comprise a light source. The device light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light).

[0135] BRIEF DESCRIPTION OF THE DRAWINGS

[0136] 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: Figs. 1 A-1C schematically depicts some embodiments of the light generating system.

[0137] Figs. 2-4 schematically depict some aspects and further embodiments of the light generating system.

[0138] Fig.5 schematically depicts some applications of the light generating system in lighting devices.

[0139] The schematic drawings are not necessarily to scale.

[0140] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0141] Fig. 1 schematically depicts embodiments of the invention comprising: a light generating system 1000 comprising a first laser light source 110, a second laser light source 120, optics 500, a luminescent material 200 and a diffuser element 400. In embodiments, the first laser light source 110 may be configured to generate first laser light 111. The first laser light 111 may have a first peak wavelength (XPi) selected from the range of 430-490 nm. Similarly, in embodiments, the second laser light source 120 may be configured to generate second laser light 121. The second laser light 121 may have a second peak wavelength (XP2) selected from the range of 430-490 nm.

[0142] Moreover, in embodiments, the light generating system 1000 may comprise a laser bank comprising a heat sinking element and lasing optics. Especially, in embodiments, the first laser light source 110 may comprise a first laser bank comprising a first laser bank heat sink, a first laser bank optical arrangement and a plurality of first lasers 10. Similarly, in embodiments, the second laser light source 120 may comprise a second laser bank comprising a second laser bank heat sink, a second laser bank optical arrangement and a plurality of second lasers 20. Note that, in embodiments, the plurality of first lasers 10 and the plurality of second lasers 20 may (also) be configured in essentially the same laser bank.

[0143] In embodiments, the optics 500 may comprise (i) a first optical element 510, configured downstream of the first laser light source 110, and (ii) a second optical element 520, configured downstream of the first optical element 510. In embodiments, the first optical element 510 may comprise one or more of a polarizing beam splitter and a dichroic beam splitter. In the light generating system 1000 as depicted in Fig. 1A subfigure I, the first optical element 510 may especially comprise at least a dichroic beam splitter. Further, in specific embodiments, the first optical element 510 may comprise a combination of a polarizing beam splitter and a dichroic beam splitter. Moreover, in embodiments, the second optical element 520 may comprise (i) one or more of a polarizing beam splitter, a dichroic beam splitter, a dichroic mirror, a dichroic cube, a dichroic sphere, a diffractive optical element, a hologram, and a semi-specular-reflecting mirror or (i) one or more of a beam combiner, a beam homogenizer, and a beam collimator. In the light generating system 1000 as depicted in Fig. 1A subfigure I, the second optical element 520 may especially comprise at least one of a dichroic beam splitter, a dichroic mirror, a dichroic cube, and a dichroic sphere.

[0144] Further, in embodiments, the luminescent material 200 may be configured downstream of the first optical element 510. The luminescent material 200 may especially be configured to convert at least part of the first laser light 111 (received by the luminescent material 200) into luminescent material light 201. As such, in embodiments, at least part of the luminescent material light 201 may propagate (via the first optical element 510) to the second optical element 520.

[0145] Furthermore, in embodiments the first optical element 510, especially the dichroic beam splitter, may be configured to at least partially transmit the first laser light 111, such as depicted in Fig. 1A subfigure I. Additionally, in embodiments, the first optical element 510, especially the dichroic beam splitter, may be configured to at least partially reflect the luminescent material light 201, such as depicted in Fig. 1 A subfigure I. Alternatively, in embodiments, the first optical element 510 may be configured to at least partially reflect the first laser light 111 (not depicted). Additionally, in embodiments, the first optical element 510, especially the dichroic beam splitter, may be configured to at least partially transmit the luminescent material light 201 (not depicted).

[0146] In embodiments, the diffuser element 400 may be configured downstream of the second laser light source 120. Especially, the diffuser element 400 may be configured to transmit and diffuse at least part of the second laser light 120 (received by the diffuser element 400) such that diffused laser light 401 propagates to the second optical element 520. More especially, in embodiments, the diffuser element 400 may be configured to transmit and diffuse the second laser light 121, such that diffused (and / or scattered) laser light 401 may be provided. Fig. 1A subfigure II schematically depicts the diffuser element 400 together with some lenses 560. As depicted in Fig. 1A subfigure II the beam of second laser light 121 provided to the lens 560 may have a first width Wl. The lens 560 may focus the beam of second laser light 121 onto the diffuser element 400. The diffuser element 400 may then diffuse and / or scatter the second laser light 121 into diffused laser light 401. The lens 560 downstream from the diffuser element 400 may collimate the diffused laser light 401 into a beam having a second width W2. As depicted here, in embodiments, the second width W2 may be larger than the first width Wl, i.e., the beam of light has been diffused and / or scattered.

[0147] Furthermore, in embodiments, the second optical element 520 may be configured to combine at least part of the luminescent material light 201 (received via the first optical element 510) and at least part of the diffused laser light 401 (received via the first diffuser element 400) into a same optical path. As a result, in embodiments, the light generating system 1000 may be configured to generate system light 1001 comprising at least part of the luminescent material light 201 and at least part of the diffused laser light 401.

[0148] Fig. IB schematically depicts an alternative embodiment of the light generating system 1000 of the invention. Here, the first laser light source 110 and the second laser light source 120 may both provide light to the luminescent material 200 (via the first optical element 510. Further, in such embodiments, the light generating system 1000 may comprise a third optical element 530 and a fourth optical element 540.

[0149] In embodiments, the third optical element 530 may be configured between the second laser light source 120 and the diffuser element 400. Hence, in embodiments, the third optical element 530 may be configured downstream of the second laser light source 120. In embodiments, the third optical element 530 may be configured to partially transmit and partially reflect the second laser light 121. Especially, in embodiments, the third optical element 530 may be configured to transmit a first part of the second laser light 121, such that it may propagate to the diffuser element 400. Conversely, in embodiments, the third optical element 530 may be configured to reflect a second part of the second laser light 121, such that it may propagate to the fourth optical element 540.

[0150] In embodiments, the fourth optical element 540 may be configured between the first laser light source 110 and the first optical element 510. Moreover, in embodiments, the fourth optical element 540 may be configured downstream of the first laser light source 110 and (the second part of the second laser light 121 from) the second laser light source 120 (emitted via the third optical element 530). In embodiments, the fourth optical element 540 may be configured to combine the first laser light 111 and the second part of the second laser light 121 into combined laser light 101. The fourth optical element 540 may further be configured to direct the combined laser light 101 to the first optical element 510.

[0151] As depicted here, in embodiments, the first optical element 510 may be configured to at least partially transmit the combined laser light 101. In such embodiments, the luminescent material 200 may be configured to convert at least part of the combined laser light 101 into luminescent material light 201. Further, in such embodiments, the first optical element 510 may be configured to reflect the luminescent material light 201 such that at least part of the luminescent material light 201 propagates (from the luminescent material 200) to the second optical element 520.

[0152] In alternative embodiments, not depicted here, the first optical element 510 may be configured to at least partially reflect the combined laser light 101. In such embodiments, the luminescent material 200 may be configured to convert at least part of the combined laser light 101 into luminescent material light 201. Further, in such embodiments, the first optical element 510 may be configured to transmit the luminescent material light 201 such that at least part of the luminescent material light 201 propagates (from the luminescent material) to the second optical element 520.

[0153] Further, as depicted, the diffuser element 400 may be configured downstream of the third optical element 530. The diffuser element 400 may especially be configured to receive the first part of the second laser light 121 (from the second laser light source 120 via the third optical element 530). Furthermore, similarly to the above described, the diffuser element 400 may be configured to transmit and diffuse the second laser light 121 such that diffused laser light 401 propagates to the second optical element 520. In the light generating system 1000 as depicted in Fig. IB, the second optical element 520 may especially comprise at least one of a dichroic beam splitter, a dichroic mirror, a dichroic cube, and a dichroic sphere.

[0154] In yet alternative embodiments, such as depicted in Fig. 1C, the first laser light source 110, the second laser light source 120 and the diffuser element 400 may be configured such that the first laser light 111 and the diffused laser light 401 may both be provided to the first optical element 510. Especially, the first optical element 510 may be configured to receive first laser light 111 and the diffused laser light 401 from essentially orthogonal directions. In such embodiments, the first optical element 510 may especially be configured to transmit at least part of the (blue) first and / or diffused laser light 111,401. Additionally, in such embodiments, the first optical element 510 may be configured to reflect at least part of the luminescent material light 201. The first optical element 510 may especially be configured to propagate the luminescent material light 201 and the diffused laser light 401 along the same optical path to the second optical element 520. Here, especially, the second optical element may comprise one or more of a beam combiner, a beam homogenizer, and a beam collimator. Furthermore, in embodiments, the system light 1001 may be white light having a correlated color temperature selected from the range of 2700-9000 K (such as from the range of 6500-9000 K) and a color rendering index of at least 70(, preferably at least 80).

[0155] Yet further, in embodiments, the light generating system 1000 may comprise one or more of a radiance enhancement film 215 and a polarization recovery component 225 configured to receive the luminescent material light 201 emitted from the luminescent material 200. Especially, in embodiments, the radiance enhancement film 215 may comprise at least one of a diffractive optical element and a micro refractive element. In embodiments, the polarization recovery component 225 may comprise a non-absorbing polarizer.

[0156] In specific embodiments, the luminescent material 200 may comprise at least a first luminescent material 210 of the type A3BsOi2:Ce3+, 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.

[0157] Further, in embodiments, the light generating system 1000 may comprise a rotating element 750 comprising one or more of the luminescent material 200 and the diffuser element 400. Fig. 2A especially depicts a rotating element 750 comprising both the luminescent material 200 and the diffuser element 400 in further detail. As depicted here, in specific embodiments, the luminescent material 200 may be configured in the reflective mode and the diffuser element 400 may be configured in the transmissive mode. In embodiments, several lenses 560 may be configured upstream and / or downstream from the luminescent material 200 and / or the diffuser element 400. The lenses 560 may especially be configured to focus light onto the respective element and / or to collimate light emitted by the respective element. Fig. 2B schematically depicts the rotating element 750 comprising both the luminescent material 200 and the diffuser element 400 implemented in the light generating system 1000. As depicted here, in such embodiments, the light generating system may further comprise additional reflectors 440 configured to (re-)direct the diffused laser light 401 to the second optical element 520.

[0158] Fig. 4 further schematically depicts a front view (as seen by a beam of light incident on the rotating element 750) of the rotating element 750. As depicted here, in embodiments, the rotating element 750 may comprise a phosphor wheel comprising one or more (concentric) rings 755. Subfigure I especially depicts an embodiment where the one or more rings 755 may comprise a first ring comprising the luminescent material 200 and a second ring comprising the diffuser element 400. Subfigure II especially depicts an embodiment where at least one of the one or more rings 755 may comprise (i) a luminescent material section 756 comprising the luminescent material 200 and (ii) a diffuser section 757 comprising the diffuser element 400. Note that, in embodiments, a combination of the embodiments depicted in subfigures I and II may be possible as well, i.e., concentric rings where one or more of the rings has separate sections.

[0159] Furthermore, in embodiments, the light generating system 1000 may comprise a safety arrangement 3000 configured, when the diffuser element 400 fails, (i) to switch off the second laser light source 120, and / or (ii) to guide the second laser light 121 to a beam dump 600. The safety mechanism 3000 may comprise a variety of components working together to provide eye-safety using several different mechanisms. Some exemplary mechanisms are illustrated in the Figs. 3. For example, Fig. 3A schematically depicts some aspects of the light generating system 1000 and the safety arrangement 3000. Here, in embodiments, the diffuser element 400 may comprise a polarization dependent diffuser 405 and a polarization rotator 410. In embodiments, the polarization rotator 410 may be configured between the second laser light source 120 and the polarization dependent diffuser 405. For this first safety mechanism, the second laser light source 120 may, in embodiments, be configured to provide second laser light 121 having a first linear polarization. The polarization rotator 410 may especially be configured to convert the second laser light 121 (received by the polarization rotator 410) having the first linear polarization into second laser light 121 having a second linear polarization (different from the first linear polarization). In embodiments, the safety arrangement 3000 may further comprise a reflective polarizer 620 and a beam dump 600. Especially, the reflective polarizer 620 may be configured between the diffuser element 400 and the second optical element 520. In embodiments, the reflective polarizer 620 may be configured (i) to transmit light having the second linear polarization to the second optical element 200 and (ii) to reflect light having the first polarization to the beam dump 600. Hence, if the diffuser element 400 were present and functioning properly, such as depicted in Fig. 3A subfigure I, the second laser light 121 having the first polarization (here p-polarization) may be converted into diffused laser light 401 having the second polarization (here s-polarization). As the reflective polarizer 620 may be configured to transmit light having the second polarization, the diffused laser light 401 may propagate further through the light generating system 1000 to the second optical element 520. However, if the diffuser element 400 were removed or not functioning properly, such as depicted in Fig. 3A subfigure II, the second laser light 121 having the first polarization (here p- polarization) may not be converted into diffused laser light 401 having the second polarization (here s-polarization), i.e., the second laser light 121 having the first polarization may be directly incident on the reflective polarized 620. As the reflective polarizer 620 may be configured to reflect light having the first polarization, the second laser light 121 having the first polarization may propagate to the beam dump 600.

[0160] In an alternative example, Fig. 3B schematically depicts a variation on the aspects of the light generating system 1000 and the safety arrangement 3000. Here, in embodiments, the safety arrangement 3000 may further comprise a laser-output sensor 635 configured to determine a laser-output signal being correlated with the output of second laser light 121 emitted by the second laser light source 120. Additionally, the safety arrangement 3000 may comprise a diffused-light sensor 630 configured to determine a diffused-light signal being correlated with the output of diffused laser light 401 emitted by the diffuser element 400. Further, the safety arrangement 3000 may comprise a control system 300. In embodiments, the control system may be configured to receive the laser-output signal and the diffused-light signal. Subsequently, in embodiments, the control system 300 may be configured to determine a safe-to-operate parameter based on the laser-output signal and the diffused-light signal. In response, in embodiments, the control system 300 may be configured to control the operation of the second laser light source 120 based on a comparison between the safe-to-operate parameter and at least one predefined threshold. Hence, if the diffuser element 400 were present and functioning properly, such as depicted in Fig. 3B subfigure I, the second laser light 121 propagating to the diffuser element 400 may trigger the laseroutput sensor 635, such that it may provide a positive laser-output signal being correlated with the output of second laser light 121. Similarly, the diffused laser light 401 emitted by the diffuser element 400 may trigger the diffused-light sensor 630, such that it may provide a positive diffused-light signal being correlated with the diffused laser light 401. In response, the control system 300 may be configured to continue operating the light generating system 1000, especially the second laser light source 120. However, if the diffuser element 400 were removed or not functioning properly, such as depicted in Fig. 3B subfigure II, the second laser light 121 propagating to the diffuser element 400 may yet trigger the laser-output sensor 635, such that it may provide a positive laser-output signal being correlated with the output of second laser light 121. However, the second laser light 121 will not be diffused into diffused laser light 401, and hence the undiffused second laser light 121 may not trigger the diffused- light sensor 630. As such, the diffused-light sensor 630 may not provide a positive diffused- light signal being correlated with the diffused laser light 401, and in response, the control system 300 may be configured to switch off the light generating system 1000, especially the second laser light source 120. In yet an alternative example, Fig. 3B schematically depicts a variation on the aspects of the light generating system 1000 and the safety arrangement 3000. Here, in embodiments, the safety arrangement 3000 may further comprise a beam dump 600 and a dichroic reflector 650. In embodiments, the dichroic reflector 650 may be configured downstream of the second laser light source 120. Moreover, in embodiments, the dichroic reflector 650 may have an optical axis (OR). In embodiments, light incident on the dichroic reflector 650 may have an angle (a) relative to the optical axis (OR). Especially, in embodiments, the dichroic reflector 650 may be configured to (i) reflect light (especially undiffused second laser light 120) having an angle a<2° to the beam dump 600, and (ii) transmit light (especially diffused laser light 401) having an angle 3°<a<45° to the second optical element 520 (optionally via one or more reflectors 640).

[0161] In yet an alternative example, Fig. 3D schematically depicts a variation on the aspects of the light generating system 1000 and the safety arrangement 3000. Here, in embodiments, the safety arrangement 3000 may further comprise a beam dump and a safety optical element (such as a reflector) 660. In embodiments, the safety optical element 660 may be configured to reflect diffused laser light 401 to the second optical element 520. Especially, the safety optical element 660 may comprise a pinhole 665 configured to transmit (undiffused) second laser light 121 to the beam dump 600.

[0162] Fig. 5 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 5 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 5 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a 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. The term “plurality” refers to two or more.

[0163] 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%.

[0164] 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".

[0165] 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.

[0166] 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.

[0167] 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.

[0168] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0169] 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”.

[0170] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments ol) the method as described herein.

[0171] 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.

[0172] 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.

[0173] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A light generating system (1000) comprising a first laser light source (110), a second laser light source (120), optics (500), a luminescent material (200) and a diffuser element (400), wherein: the first laser light source (110) is configured to generate first laser light (111) having a first peak wavelength (Xpi) selected from the range of 430-490 nm; the second laser light source (120) is configured to generate second laser light (121) having a second peak wavelength (XP2) selected from the range of 430-490 nm; the optics (500) comprises (i) a first optical element (510), configured downstream of the first laser light source (110), and (ii) a second optical element (520), configured downstream of the first optical element (510); the luminescent material (200) is configured downstream of the first optical element (510); the luminescent material (200) is configured to convert at least part of the first laser light (111) into luminescent material light (201), such that at least part of the luminescent material light (201) propagates to the second optical element (520); wherein one of the following applies:(i) the first optical element (510) is configured to (a) at least partially transmit the first laser light (111), and (b) at least partially reflect the luminescent material light (201);(ii) the first optical element (510) is configured to (a) at least partially reflect the first laser light (111), and (b) at least partially transmit the luminescent material light (201); the diffuser element (400) is configured downstream of the second laser light source (120); the diffuser element (400) is configured to transmit and diffuse at least part of the second laser light (120) such that diffused laser light (401) propagates to the second optical element (520); the second optical element (520) is configured to combine at least part of the luminescent material light (201) and at least part of the diffused laser light (401) into a same optical path; and the light generating system (1000) is configured to generate system light (1001) comprising at least part of the luminescent material light (201) and at least part of the diffused laser light (401); andwherein the optics (500) further comprises a third optical element (530) and a fourth optical element (540); wherein: the third optical element (530) is configured between the second laser light source (120) and the diffuser element (400); wherein the third optical element (530) is configured to partially transmit and partially reflect the second laser light (121) such that a first part of the second laser light (121) propagates to the diffuser element (400) and a second part of the second laser light (121) propagates to the fourth optical element (540), the fourth optical element (540) is configured between the first laser light source (110) and the first optical element (510); wherein the fourth optical element (540) is configured downstream of the first laser light source (110) and the second laser light source (120); wherein the fourth optical element (540) is configured to combine the first laser light (111) and the second part of the second laser light (121) into combined laser light (101), and to direct the combined laser light (101) to the first optical element (510); and wherein one of the following applies:(i) the first optical element (510) is configured to at least partially transmit the combined laser light (101); wherein the luminescent material (200) is configured to convert at least part of the combined laser light (101) into luminescent material light (201); and wherein the first optical element (510) is configured to reflect the luminescent material light (201) such that at least part of the luminescent material light (201) propagates to the second optical element (520); or(ii) the first optical element (510) is configured to at least partially reflect the combined laser light (101); wherein the luminescent material (200) is configured to convert at least part of the combined laser light (101) into luminescent material light (201), and wherein the first optical element (510) is configured to transmit the luminescent material light (201) such that at least part of the luminescent material light (201) propagates to the second optical element (520); the diffuser element (400) is configured downstream of the third optical element (530), wherein the diffuser element (400) is configured to receive the first part of the second laser light (121), and wherein the diffuser element (400) is configured to transmit the second laser light (121) such that diffused laser light (401) propagates to the second optical element (520); and wherein the light generating system (1000) further comprises lenses (560), the lenses comprises a lens (560) upstream from the diffuser element (400) and a lens (560) downstream from the diffuser element (400), the lens (560) upstream from the diffuserelement (400) is configured to focus a beam of second laser light (121) having a first width, Wl, onto the diffuser element (400), the lens (560) downstream from the diffuser element (400) is configured to collimate the diffused laser light (401) into a beam having a second width, W2; and wherein the luminescent material (200) comprises at least a first luminescent material (210) of the type A3BsOi2:Ce3+, 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.

2. The light generating system (1000) according to claim 1, wherein the second width, W2, is larger than the first width, WL3. The light generating system (1000) according to any one of the preceding claims, wherein the system light (1001) is white light having a correlated color temperature selected from the range of 2700-9000 K and a color rendering index of at least 60.

4. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises one or more of a radiance enhancement film (215) and a polarization recovery component (225) configured to receive the luminescent material light (201) emitted from the luminescent material (200); wherein the radiance enhancement film (215) comprises at least one of a diffractive optical element and a micro refractive element; and wherein the polarization recovery component (225) comprises a non-absorbing polarizer.

5. The light generating system (1000) according to any one of the preceding claims, wherein the first laser light source (110) comprises a first laser bank comprising a first laser bank heat sink, a first laser bank optical arrangement and a plurality of first lasers (10); wherein the second laser light source (120) comprises a second laser bank comprising a second laser bank heat sink, a second laser bank optical arrangement and a plurality of second lasers (20); wherein the first peak wavelength (XPi) and the second peak wavelength (XP2) are individually selected from the wavelength range of 435-465 nm.

6. The light generating system (1000) according to any one of the preceding claims, wherein the first optical element (510) comprises a combination of a polarizing beam splitter and a dichroic beam splitter, and / or wherein the second optical element (520)comprises (i) one or more of a polarizing beam splitter, a dichroic beam splitter, a dichroic mirror, a dichroic cube, a dichroic sphere, a diffractive optical element, a hologram, and a semi-specular-reflecting mirror or (ii) one or more of a beam homogenizer and a beam collimator.

7. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent material (200) is configured in the reflective mode and wherein the diffuser element (400) is configured in the transmissive mode.

8. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a rotating element (750) comprising one or more of (a) the luminescent material (200) and (b) the diffuser element (400).

9. The light generating system (1000) according to claim 8, wherein the rotating element (750) comprises a phosphor wheel comprising one or more rings (755), wherein one or more of the following applies: (a) the one or more rings (755) comprise a first ring comprising the luminescent material (200) and a second ring comprising the diffuser element (400); and (b) at least one of the one or more rings (755) comprises (i) a luminescent material section (756) comprising the luminescent material (200) and (ii) a diffuser section (757) comprising the diffuser element (400).

10. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a safety arrangement (3000) configured to, when the diffuser element (400) fails, (i) to switch off the second laser light source (120), and / or (ii) to guide the second laser light (121) to a beam dump (600).

11. The light generating system (1000) according to claim 10, wherein the diffuser element (400) comprises a polarization dependent diffuser (405) and a polarization rotator (410); wherein the polarization rotator (410) is configured between the second laser light source (120) and the polarization dependent diffuser (405); wherein the second laser light source (120) is configured to provide second laser light (121) having a first linear polarization; wherein the polarization rotator (410) is configured to convert the second laser light (121) having the first linear polarization into second laser light (121) having a secondlinear polarization; wherein the safety arrangement (3000) further comprises a reflective polarizer (620) and a beam dump (600); wherein the reflective polarizer (620) is configured between the diffuser element (400) and the second optical element (520); and wherein the reflective polarizer (620) is configured (i) to transmit light having the second linear polarization to the second optical element (200) and (ii) to reflect light having the first polarization to the beam dump (600).

12. The light generating system (1000) according to claim 10, wherein the safety arrangement (3000) further comprises a laser-output sensor (635) configured to determine a laser-output signal being correlated with the output of second laser light (121) emitted by the second laser light source (120), a diffused-light sensor (630) configured to determine a diffused-light signal being correlated with the output of diffused laser light (401) emitted by the diffuser element (400), and a control system (300) configured to (i) receive the laseroutput signal and the diffused-light signal, (ii) determine a safe-to-operate parameter based on the laser-output signal and the diffused-light signal, and (iii) control the operation of the second laser light source (120) based on a comparison between the safe-to-operate parameter and at least one predefined threshold.

13. The light generating system (1000) according to claim 10, wherein the safety arrangement (3000) further comprises a beam dump (600) and a dichroic reflector (650); wherein the dichroic reflector (650) is configured downstream of the second laser light source (120); wherein the dichroic reflector (650) has an optical axis (OR), wherein light incident on the dichroic reflector (650) has an angle (a) relative to the optical axis (OR), wherein the dichroic reflector (650) is configured to (i) reflect light having an angle a<2° to the beam dump (600), and (ii) transmit light having an angle 3°<a<45° to the second optical element (520).

14. The light generating system (1000) according to claim 10, wherein the safety arrangement (3000) further comprises (i) a safety optical element (660) configured to reflect diffused laser light (401) to the second optical element (520) and (ii) a beam dump (600); wherein the safety optical element (660) comprises a pinhole (665) configured to transmit second laser light (121) to the beam dump (600).

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

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