Laser combination configuration for obtaining white stage lighting without differential aging

Abstract

The invention provides a light generating system comprising a first light generating arrangement, a second light generating arrangement, a luminescent material, one or more diffusers, a main beam splitter, dichroic beam splitters, a light exit, and a control system; wherein: (A) the first light generating arrangement may comprise a plurality of first light generating devices configured to generate first device light having a first peak wavelength (λp1); (B) the second light generating arrangement may comprise a plurality of second light generating devices configured to generate second device light having a second peak wavelength (λp2); wherein 0 nm ≤ |λp1-λp2| ≤ 15 nm; (C) the luminescent material may be configured (a) to convert at least part of the first device light into first device light generated luminescent material light, and (b) to convert at least part of the second device light into second device light generated luminescent material light; (D) the light generating system may be configured such that the first device light and second device light received by the main beam splitter may comprise polarized light; wherein the main beam splitter may be configured (a) to direct a primary first part of the first device light to the luminescent material and a secondary first part of the first device light to at least one of the one or more diffusers, and (b) to direct a primary second part of the second device light to the luminescent material and a secondary second part of the second device light to at least one of the one or more the diffusers; (E) at least one of the one or more diffusers may be configured to convert at least part of the secondary first part of the first device light into first device light based diffused light, and at least one of the one or more diffusers may be configured to convert at least part of the secondary second part of the second device light into second device light based diffused light; (F) the light generating system may be configured to generate system light comprising one or more of (a) first device light generated system light comprising at least part of the first device light based diffused light and at least part of the first device light generated luminescent material light, and (b) second device light generated system light comprising at least part of the second device light based diffused light and at least part of the second device light generated luminescent material light; wherein the first and second device light generated system light are white light; and (G) the control system may be configured to control the first light generating arrangement and the second light generating arrangement.

Description

[0001] LASER COMBINATION CONFIGURATION FOR OBTAINING WHITE STAGE

[0002] LIGHTING WITHOUT DIFFERENTIAL AGING

[0003] FIELD OF THE INVENTION

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

[0005] BACKGROUND OF THE INVENTION

[0006] 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.

[0007] SUMMARY OF THE INVENTION

[0008] 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. Furthermore, such phosphors exhibit a pump-dependent color shift (e.g. for white LED lighting) where the phosphors exhibit differential droop. Hence, it is desired to provide a light generating system with tunable color temperature and tunable spectral properties while limiting differential droop.

[0009] 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.

[0010] According to a first aspect, the invention provides a light generating system comprising a first light generating arrangement, a second light generating arrangement, a luminescent material, one or more diffusers, a main beam splitter, dichroic beam splitters, a light exit, and a control system. In embodiments, the first light generating arrangement may comprise a plurality of first light generating devices configured to generate first device light having a first peak wavelength (kpi). Moreover, in embodiments, the first light generating arrangement may comprise a first laser bank comprising the plurality of first light generating devices. Especially, in embodiments, the first light generating devices may comprise first laser diodes. The second light generating arrangement may, in embodiments, comprise a plurality of second light generating devices configured to generate second device light having a second peak wavelength (Xp2). In embodiments, the second light generating arrangement may comprise a second laser bank comprising the plurality of second light generating devices. Especially, in embodiments, the plurality of second light generating devices may comprise second laser diodes. Further, in embodiments, 0 nm < |Xpi-Xp2| < 15 nm (may apply). The luminescent material may, in embodiments, be configured in a light receiving relationship with the first light generating arrangement and may be configured to convert at least part of the first device light into first device light generated luminescent material light. Additionally, in embodiments, the luminescent material may be configured in a light receiving relationship with the second light generating arrangement and may be configured to convert at least part of the second device light into second device light generated luminescent material light. Moreover, in embodiments, the light generating system may be configured such that the first device light received by the main beam splitter may comprise polarized light and the second device light received by the main beam splitter may comprise polarized light. Furthermore, in embodiments, the main beam splitter may be configured to direct a primary first part of the first device light to the luminescent material and a secondary first part of the first device light to at least one of the one or more diffusers. Additionally, in embodiments, the main beam splitter may be configured to direct a primary second part of the second device light to the luminescent material and a secondary second part of the second device light to at least one of the one or more the diffusers. Furthermore, a first dichroic beam splitter may, in embodiments, be configured to direct at least part of the first device light or at least part of the second device light to the main beam splitter. Additionally, in embodiments, the first dichroic beam splitter may be configured to direct at least part of the luminescent material light to an auxiliary dichroic beam splitter. Moreover, in embodiments, at least one of the one or more diffusers may be configured in a light receiving relationship with the first light generating arrangement. As such, in embodiments, the at least one of the one or more diffusers may be configured to convert at least part of the secondary first part of the first device light into first device light based diffused light. Additionally, in embodiments, at least one of the one or more diffusers may be configured in a light receiving relationship with the second light generating arrangement. As such, in embodiments, the at least one of the one or more diffusers may be configured to convert at least part of the secondary second part of the second device light into second device light based diffused light. Furthermore, in embodiments, the auxiliary dichroic beam splitter may be configured to direct (a) first device light generated luminescent material light and first device light based diffused light, and (b) second device light generated luminescent material light and second device light based diffused light along a same optical path to the light exit of the light generating system. The light generating system may therefore, in embodiments, be configured to generate system light comprising one or more of (a) first device light generated system light comprising at least part of the first device light based diffused light and at least part of the first device light generated luminescent material light, and (b) second device light generated system light comprising at least part of the second device light based diffused light and at least part of the second device light generated luminescent material light. Especially, in embodiments, the first device light generated system light and the second device light generated system light may be white light. Furthermore, in embodiments, the control system may be configured to control the first light generating arrangement and the second light generating arrangement. Hence, in embodiments, the invention provides a light generating system comprising a first light generating arrangement, a second light generating arrangement, a luminescent material, one or more diffusers, a main beam splitter, dichroic beam splitters, a light exit, and a control system; wherein: (i) the first light generating arrangement may comprise a plurality of first light generating devices configured to generate first device light having a first peak wavelength (kpl); wherein the first light generating arrangement may comprise a first laser bank comprising the plurality of first light generating devices; wherein the first light generating devices may comprise first laser diodes; (ii) the second light generating arrangement may comprise a plurality of second light generating devices configured to generate second device light having a second peak wavelength (Zp2); wherein the second light generating arrangement may comprise a second laser bank comprising the plurality of second light generating devices; wherein the plurality of second light generating devices may comprise second laser diodes; wherein 0 nm < |Xpl-Xp2| < 15 nm; (iii) the luminescent material may be configured (a) in a light receiving relationship with the first light generating arrangement and may be configured to convert at least part of the first device light into first device light generated luminescent material light, and (b) in a light receiving relationship with the second light generating arrangement and may be configured to convert at least part of the second device light into second device light generated luminescent material light; (iv) the light generating system may be configured such that the first device light received by the main beam splitter may comprise polarized light and the second device light received by the main beam splitter may comprise polarized light; wherein the main beam splitter may be configured (a) to direct a primary first part of the first device light to the luminescent material and a secondary first part of the first device light to at least one of the one or more diffusers, and (b) to direct a primary second part of the second device light to the luminescent material and a secondary second part of the second device light to at least one of the one or more the diffusers; (v) a first dichroic beam splitter may be configured (a) to direct at least part of the first device light or at least part of the second device light to the main beam splitter and (b) to direct at least part of the luminescent material light to an auxiliary dichroic beam splitter; (vi) at least one of the one or more diffusers may be configured in a light receiving relationship with the first light generating arrangement and may be configured to convert at least part of the secondary first part of the first device light into first device light based diffused light, and at least one of the one or more diffusers may be configured in a light receiving relationship with the second light generating arrangement and may be configured to convert at least part of the secondary second part of the second device light into second device light based diffused light; (vii) the auxiliary dichroic beam splitter may be configured to direct (a) first device light generated luminescent material light and first device light based diffused light, and (b) second device light generated luminescent material light and second device light based diffused light, along a same optical path to the light exit of the light generating system; (viii) the light generating system may be configured to generate system light comprising one or more of (a) first device light generated system light comprising first device light based diffused light and first device light generated luminescent material light, and (b) second device light generated system light comprising second device light based diffused light and second device light generated luminescent material light; wherein the first device light generated system light and the second device light generated system light may be white light; and (ix) the control system may be configured to control the first light generating arrangement and the second light generating arrangement.

[0011] With such system, a high power light generating system may be provided. Especially, with such system high intensity, correlated color temperature (CCT) control as well as a high color rendering index (CRI) may be possible. 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. Especially, light generating system laser combination configuration may provide (high intensity) white stage lighting, or other types of light, with a reduced differential aging or even without differential aging. Especially, the luminescent material may be illuminated by the first device light and / or the second device light. Therefore, the luminescent materials may experience the same extent (or amount) of droop i.e., differential droop between the two types of luminescent material may be reduced. In this way, the shift in the color point and / or the color rendering index (CRI) of the light generating system may be reduced.

[0012] In embodiments, the light generating system may thus comprise a first light generating arrangement, a second light generating arrangement, a luminescent material, one or more diffusers, a main beam splitter, dichroic beam splitters, a light exit, and a control system. Here below, embodiments of the different elements of the light generating system will be described in further detail.

[0013] The first light generating arrangement may, in embodiments, comprise a first light generating device. Especially, in embodiments, the first light generating arrangement may comprise a plurality of first light generating devices. Hence, herein the term “first light generating device” and similar terms may also refer to “a plurality of first light generating devices”. In embodiments, the (plurality of) first light generating device(s) may be configured to generate first device light. Especially, in embodiments, the first device light may have a first peak wavelength (Xpi). In embodiments, the first peak wavelength (Xpi) may especially be selected from the visible wavelength range. However, in other embodiments, the first peak wavelength (Xpi) may also be selected from one of the IR and the UV wavelength range. The first peak wavelength (Xpi) may especially, in embodiments, be selected from the range of 380-780 nm, such as from the range of 380-570 nm, like from the range of 400-500 nm, such as from the range of 440-490 nm. Hence, in some embodiments, the first device light may be blue light, however, this may not necessarily be the case.

[0014] Further, in embodiments, the first light generating device may comprise a first light source. In embodiments, the first light generating device may especially comprise a solid state light source. Especially, in embodiments, the first light generating device may comprise one of a light emitting diode (LED), a laser diode, and a superluminescent diode. More especially, in embodiments, the (plurality of) first light generating devices may comprise first laser diodes. In such embodiments, the first light generating arrangement may comprise a first laser bank. Especially, in embodiments the first light generating arrangement may comprise a plurality of first light generating devices configured in the first laser bank.

[0015] A laser bank may comprise a light emitting arrangement comprising an (2D) array of a plurality of laser diodes, e.g. arranged on a thermally conductive carrier and optionally 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 in embodiments 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. In embodiments, lasers in a laser bank (or “laser array bank”) may especially share the same optics. Laser banks may also be used to boast the input power.

[0016] Hence, in embodiments, the (plurality of) first laser diodes may be configured (especially arranged) in the first laser bank. Further, in embodiments, the plurality of first light generating devices may all comprise essentially the same first (solid state) light sources, especially first light sources selected from the same bin. However, in other embodiments, the plurality of first light generating devices may comprise different first (solid state) light sources. Further embodiments, of the light sources are described further below.

[0017] Similarly, in embodiments, the second light generating arrangement may comprise a second light generating device. Especially, in embodiments, the second light generating arrangement may comprise a plurality of second light generating devices. Hence, herein the term “second light generating device” and similar terms may also refer to “a plurality of second light generating devices”. In embodiments, the (plurality of) second light generating device(s) may be configured to generate second device light. Especially, in embodiments, the second device light may have a second peak wavelength (Xp2). In embodiments, the second peak wavelength (Xp2) may especially be selected from the visible wavelength range. However, in other embodiments, the second peak wavelength (Xp2) may also be selected from one of the IR and the UV wavelength range. The second peak wavelength (Xp2) may especially, in embodiments, be selected from the range of 380-780 nm, such as from the range of 380-570 nm, like from the range of 400-500 nm, such as from the range of 440-490 nm. Hence, in some embodiments, the second device light may be blue light, however, this may not necessarily be the case.

[0018] Further, in embodiments, the second light generating device may comprise a second light source. In embodiments, the second light generating device may especially comprise a solid state light source. Especially, in embodiments, the second light generating device may comprise one of a light emitting diode (LED), a laser diode, and a superluminescent diode. More especially, in embodiments, the (plurality of) second light generating devices may comprise second laser diodes. In such embodiments, the second light generating arrangement may comprise a second laser bank (see also above about laser banks). Especially, in embodiments the second light generating arrangement may comprise a plurality of second light generating devices configured in the second laser bank. Hence, in embodiments, the (plurality of) second laser diodes may be configured (especially arranged) in the second laser bank. Further, in embodiments, the plurality of second light generating devices may all comprise essentially the same second (solid state) light sources, especially second light sources selected from the same bin. However, in other embodiments, the plurality of second light generating devices may comprise different second (solid state) light sources.

[0019] In embodiments, the first peak wavelength (Xpi) and the second peak wavelength (Xp2) may be selected relatively close to each other, i.e., the first device light and the second device light may have substantially the same color. Especially, in embodiments, 0 nm < |Xpi-Xp2| < 30 nm, such as, 0 nm < |Xpi-Xp2| < 15 nm, like 2 nm < |Xpi-Xp2| < 10 nm.

[0020] The first light generating arrangement and the second light generating arrangement may both be configured to provide light to the luminescent material. Hence, in embodiments, the luminescent material may be configured in a light receiving relationship with the first light generating arrangement. Additionally or alternatively, in embodiments, the luminescent material may be configured in a light receiving relationship with the second light generating arrangement. As such, in embodiments, the luminescent material may be configured to convert at least part of the first device light received by the luminescent material into first device light generated luminescent material light (i.e. especially luminescent material light generated by the luminescent material due to conversion of first device light). Similarly, in embodiments, the luminescent material may be configured to convert at least part of the second device light received by the luminescent material into second device light generated luminescent material light (i.e. especially luminescent material light generated by the luminescent material due to conversion of second device light).

[0021] The phrase “... light received by ...”, and similar phrases, such as “device light received by the 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. The phrase “to convert at least part of the device light received by the luminescent material into luminescent material light”, and similar phrases, may thus indicate that when at least part of device light indeed irradiates the luminescent material (in an operational mode of the light generating system), then at least part of that device light may be converted into luminescent material light.

[0022] Especially, in embodiments, at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the first device light received by the luminescent material may be converted into first device light generated luminescent material light. Similarly, in embodiments, at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the second device light received by the luminescent material may be converted into second device light generated luminescent material light.

[0023] In embodiments, the first device light generated luminescent material light and the second device light generated luminescent material light may (both) have a spectral power distribution with at least intensity in the visible wavelength range.

[0024] Here below, some general aspects in relation to luminescent materials are described. 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.

[0025] 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. 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 (kex<kem), 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 (kex>kem). 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. 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. 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.

[0026] In specific embodiments the luminescent material comprises a luminescent material of the type AsBsOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B comprises aluminum (Al), however, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of Al, more especially up to about 10 % of Al (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yl-xLux^BsOn 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 (Yl-xLux^ALOn Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.89Ceo.oi)3A150i2. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0027] In embodiments, the luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-0 may be replaced by Si-N. In specific embodiments the luminescent material comprises (YXI-X2- x3A’X2CeX3)3(Alyi-y2B’y2)5Oi2, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially xl>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions.

[0028] In specific embodiments at maximum 10% of B-0 may be replaced by Si-N. Here, B in B-0 refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in specific embodiments B-0 may refer to Al-O. As indicated above, in specific embodiments x3 may be selected from the range of 0.001-0.04. Especially, such luminescent materials may have a suitable spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (optionally in combination with (the) light of other sources of light as described herein). Hence, in specific embodiments A may be selected from the group consisting of Lu and Gd. Alternatively or additionally, B may comprise Ga. Hence, in embodiments the luminescent material comprises (YXI-X2- x3(Lu,Gd)x2Cex3)3(Alyi-y2Gay2)5Oi2, wherein Lu and / or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3<0.1, and wherein 0<y2<0.1. Further, in specific embodiments, at maximum 1% of B-0 may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yxi-xsCexs^ALOn, wherein xl+x3=l, and wherein 0<x3<0.2, such as 0.001-0.1.

[0029] In specific embodiments, the light generating device may only include luminescent materials selected from the type of cerium comprising garnets. In even further specific embodiments, the light generating device includes a single type of luminescent materials, such as (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Hence, in specific embodiments the light generating device comprises luminescent material, wherein at least 85 weight%, even more especially at least about 90 wt.%, such as yet even more especially at least about 95 weight % of the luminescent material comprises (Yxi-x2-x3A’x2Cex3)3(Alyi-y2B’y2)5Oi2. Here, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc, wherein xl+x2+x3=l, wherein x3>0, wherein 0<x2+x3<0.2, wherein yl+y2=l, wherein 0<y2<0.2. Especially, x3 is selected from the range of 0.001-0.1. Note that in embodiments x2=0. Alternatively or additionally, in embodiments y2=0. In specific embodiments, A may especially comprise at least Y, and B may especially comprise at least Al.

[0030] Alternatively or additionally, the luminescent material may comprise a luminescent material of the type AsSieNiuCe3, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y.

[0031] The garnet type luminescent material may also be described with an alternative formula AsB^C’^On. Here, A may comprise one or more of (i) rare earth ions, such as one or more selected from Y3+, Lu3+, Gd3+, Tb3+, La3+, and (ii) divalent cations, such as Ca2+. Here, B may comprise one or more of (i) trivalent cations, such as one or more of Al3+, Ga3+, Sc3+, Sb3+, and In3+, and (ii) divalent cations, such as one or more of Mg2+and Mn2+. Here, C may comprise one or more of (i) trivalent cations, such as one or more of Ga3+and Al3+, (ii) divalent cations, such as Mn2+, and (iii) tetravalent cations, such as one or more of Si4+and Ge4+. With such ions, the garnet crystal structure can be maintained. Other substitutions than mentioned may also be possible.

[0032] 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. Hence, the term “luminescent material” herein especially relates to inorganic luminescent materials. Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc..

[0033] 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).

[0034] 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. Further embodiments of the luminescent material will be described in more detail below. To facilitate the light-receiving relationship of the luminescent material with the light generating device, the light generating system may comprise the main beam splitter. In embodiments, the main beam splitter may be configured in an optical path between the first light generating arrangement and the luminescent material. Additionally, in embodiments, the main beam splitter may (also) be configured in an optical path between the second light generating arrangement and the luminescent material. Especially, the main beam splitter may be configured upstream from the first light generating arrangement and the second light generating arrangement, and downstream from the luminescent material and the one or more diffusers. 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 first and second light generating devices), 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”.

[0035] In embodiments, the main beam splitter may especially be configured, such that first device light and second device light may propagate from the first light generating arrangement and the second light generating arrangement, respectively, via the main beam splitter to at least the luminescent material. Therefore, in embodiments, the main beam splitter may comprise one or more of (i) a dichroic beam splitter (see also further below) and (ii) a polarizing beam splitter.

[0036] In embodiments, the polarizing beam splitter may be configured to transmit and / or reflect at least part of the device light in dependence of its polarization. Especially, for elliptically polarized device light the angle the polarization direction of the device light makes with respect to the polarization axis of the polarizing beam splitter (see also further below) may determine the fraction of device light which will be reflected (p polarization) and fraction which will be transmitted (s polarization)(or vice versa).

[0037] Hence, in embodiments, the polarization direction of the device light may have an angle with the polarization direction of the polarizing beam splitter, see also further below. Such an angle may be achieved through rotation of the light generating arrangement, or of the individual lasers, and the polarizing beam splitter relative to each other. For example, in embodiments, during production of the light generating system the laser bank may be angled relative to the polarizing beam splitter. In such embodiments, the angle, and thus the light generating arrangement (especially the laser bank) and the polarizing beam splitter may be essentially fixed during use of the light generating system. However, this may not necessarily be the case. For example, in other embodiments, the angle, and thus the light generating arrangement (especially the laser bank) and the polarizing beam splitter may be changed during use of the light generating system, see also further below.

[0038] Herein, in embodiments, the main beam splitter may comprise a polarizing beam splitter configured to split light having a wavelength selected from the blue wavelength range (however in other embodiments this may also be a different wavelength range) based on its polarization. In such embodiments, light having a wavelength different from the blue wavelength range may be substantially transmitted by the polarizing beam splitter. Especially, the polarizing beam splitter may be selected such that the first device light generated luminescent material light and / or the second device light generated luminescent material light are substantially transmitted.

[0039] Hence, for the polarizing beam splitter may apply that for a first polarization, the transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30 % points, than for a second polarization. Similarly, for a first polarization, the reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30 % points, than for a second polarization. Especially, in embodiments, the dichroic beam splitter may be configured to direct at least 60% of the light of the first polarization to a first direction and at least 60% of the light of the second polarization to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45-135°, such as about 90°. The percentage of the light may refer to a spectral power (e.g. in Watt). Especially, the first polarization and the second polarization may comprise linear polarizations such as selected from s polarization and p polarization. Optionally, the first polarization and the second polarization may be selected from different elliptically polarized light. In embodiments, the polarizing beam splitters herein may be selected from reflective polarizing beam splitters (reflective polarizers).

[0040] In embodiments, the main beam splitter may optionally comprise a dichroic beam splitting function. In embodiments, the dichroic beam splitter may be configured to transmit and / or reflect at least part of the device light in dependence of its spectral power (rather than its polarization). Especially, the dichroic beam splitter may be selected such that the first device light generated luminescent material light and / or the second device light generated luminescent material light are substantially transmitted, and the device light may essentially be reflected. However, the other way around, i.e. the dichroic beam splitter may be selected such that the first device light generated luminescent material light and / or the second device light generated luminescent material light are substantially reflected, and the device light may essentially be transmitted, may in (other) embodiments also be possible.

[0041] Hence, for the dichroic beam splitter may apply that for a first wavelength range, the wavelength averaged transmission may be higher, like at least 10% points higher, such as at least 20% points higher, or even at least 30 % points, than for a second wavelength range. Similarly, for a first wavelength range, the wavelength averaged reflection may be lower, like at least 10% points lower, such as at least 20% points lower, or even at least 30 % points, than for a second wavelength range. Especially, in embodiments, the dichroic beam splitter may be configured to direct at least 60% of the light of the first wavelength range to a first direction and at least 60% of the light of the second wavelength range to a second direction, wherein the directions may in embodiments have a mutual angle selected from the range 45-135°, such as about 90°. The percentage of the light may refer to a spectral power (e.g. in Watt).

[0042] Hence, in embodiments, the main beam splitter may also comprise a beam splitter with a combined dichroic and polarizing beam splitting functionality.

[0043] Hence, in embodiments, the light generating system may be configured such that the first device light received by the main beam splitter may comprise polarized light. Similarly, in embodiments, the light generating system may be configured such that the second device light received by the main beam splitter may comprise polarized light. In embodiments, the (first and / or second) light generating devices may be configured to generate polarized (laser) light, such that the device light received by the main beam splitter may comprise polarized light. In other embodiments, the light generating system may comprise one or more polarization control elements configured to change the first device light and / or second device light into polarized first device light and / or polarized second device light, respectively. Especially, in embodiments, the (first and / or second) device light may comprise linearly polarized light, i.e., one or more of polarized light having a p- polarization and polarized light having an s-polarization. Additionally or alternatively, in embodiments, the (first and / or second) device light may comprise elliptically polarized light, such as e.g. right handed circular polarized light or left handed circular polarized light. The polarization of the first device light and the second device light will be described in more detail further below. In embodiments, the first device light and the second device light may especially comprise polarized light having a controllable polarization. As a result, the main beam splitter may be configured to direct parts of the first and / or second device light to the luminescent material and other parts of the first and / or second device light to the one or more diffusers, especially doing so in dependence of the polarizations of the respective first and / or second device light. Especially, in embodiments, the main beam splitter may be configured to direct a primary first part of the first device light to the luminescent material. Additionally or alternatively, in embodiments, the main beam splitter may be configured to direct a secondary first part of the first device light to at least one of the one or more diffusers. Similarly, in embodiments, the main beam splitter may be configured to direct a primary second part of the second device light to the luminescent material. Additionally or alternatively, in embodiments, the main beam splitter may be configured to direct a secondary second part of the second device light to at least one of the one or more diffusers. The light generating system may, in embodiments, be configured such that the following actions of the main beam splitter may occur simultaneously: (a) to direct the primary first part of the first device light to the luminescent material and to direct the secondary first part of the first device light to at least one or the one or more diffusers, and (b) to direct the primary second part of the second device light to the luminescent material and to direct the secondary second part of the second device light to at least one or the one or more diffusers. However, in other embodiments, the light generating system may be configured such that the previously indicated actions may occur apart from each other (such as e.g. individually, consecutively, or only partially, see also further below). Especially, in embodiments, the actions occurring in the light generating system may be adjusted in dependence of differential aging of the light generating arrangements and / or pulse width modulation.

[0044] Herein the term “to direct X light to Y” and similar phrases may refer to one or more of reflection of X light in the direction of (or towards) Y, transmission of X light in the direction of (or towards) Y (i.e., allowing the light X to pass through in the direction of Y), and refraction of X light in the direction of (or towards) Y.

[0045] Further, in embodiments, as indicated above the light generating system may comprises one or more dichroic beam splitters. Especially, in embodiments, the light generating system may comprise a first dichroic beam splitter configured in an optical path between the first light generating arrangement or the second light generating arrangement, such as the first light generating arrangement, or such as the second light generating arrangement, and the main beam splitter. As such, in embodiments, the first dichroic beam splitter may be configured to direct at least part of the first device light or at least part of the second device light to the main beam splitter. Especially, in embodiments, the first dichroic beam splitter may be configured to direct at least 60% of the (first or second) device light (received by the first dichroic beam splitter) to the main beam splitter, such as at least 70%, like at least 80%, especially at least 90%, such as at least 95%, including 100%. Additionally or alternatively, in embodiments, the first dichroic beam splitter may be configured to direct at least part of the (first device light generated and / or second device light generated) luminescent material light to an auxiliary dichroic beam splitter (see also further below). Especially, in embodiments, the first dichroic beam splitter may be configured to direct at least 60% of the (first device light generated and / or second device light generated) luminescent material light (received by the first dichroic beam splitter) to the auxiliary dichroic beam splitter, such as at least 70%, like at least 80%, especially at least 90%, such as at least 95%, including 100%.

[0046] Additionally to the luminescent material, the light generating system may also comprise one or more diffusers. In specific embodiments, the light generating system may comprise a single diffuser. However, in other embodiments, the light generating system may comprise more than one diffuser, such as two diffusers, or even three diffusers. Use of more than one diffuser may be advantageous as it reduces diminishing effects of aging of one diffuser as well as provides opportunities for the dissipation of heat and thus thermal management.

[0047] The at least one or more diffusers may especially be configured in a light receiving relationship with one or more, especially both of, the first light generating arrangement and the second light generating arrangement. Especially, in embodiments, at least one (or even all) of the one or more diffusers may be configured in a light receiving relationship with the first light generating arrangement. More especially, at least one (or even all) of the one or more diffusers may be configured to convert at least part of the secondary first part of the first device light into first device light based diffused light. Especially, in embodiments, at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the (secondary first part of the) first device light received by (one of) the one or more diffusers may be converted into first device light based diffused light. Similarly, in embodiments, at least one (or even all) of the one or more diffusers may be configured in a light receiving relationship with the second light generating arrangement. More especially, at least one (or even all) of the one or more diffusers may be configured to convert at least part of the secondary second part of the second device light into second device light based diffused light. Especially, in embodiments, at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the (secondary second part of the) second device light received by (one of) the one or more diffusers may be converted into second device light based diffused light. The term “device light based diffused light”, and similar terms, may refer to diffuse(d) light that is generated by a diffuser when irradiating with the device light. Hence, the device light may be converted in to diffuse device light, or “first device light based diffused light”.

[0048] In some embodiments, the light generating system may comprise one diffuser configured in a light-receiving relationship with both the first light generating arrangement and the second light generating arrangement. As such, in an operational mode of the light generating system the diffuser may receive at least part of both the secondary first part of the first device light and the secondary second part of the second device light. In another operational mode of the light generating system the diffuser may receive at least part of only one of the secondary first part of the first device light and the secondary second part of the second device light, e.g. through operation of only the first or the second light generating device. Moreover, in some embodiments, the light generating system may comprise more than one diffuser. In such embodiments, each diffuser may be configured in a light-receiving relationship with a different light generating arrangement. For example, in embodiments, the first device light originating from the first light generating device may be incident on (only) a first diffuser, and the second device light originating from the second light generating device may be incident on (only) a second diffuser. However, in other embodiments, the more than one diffusers may (all) be configured to, in an operational mode of the light generating system, receive both the secondary first part of the first device light and the secondary second part of the second device light. Further embodiments of the diffuser will be described in more detail below.

[0049] The light generating system is further, in embodiments, configured such that the first device light generated luminescent material light, the second device light generated luminescent material light, the first device light based diffused light, and the second device light based diffused light may be combined. Therefore, in embodiments, the light generating system may comprise the auxiliary dichroic beam splitter. Especially, in embodiments, the auxiliary dichroic beam splitter may be configured downstream of one or more of the one or more diffusers and upstream of the light exit. As such, in embodiments, the auxiliary dichroic beam splitter may be configured to direct (a) first device light generated luminescent material light and first device light based diffused light, and (b) second device light generated luminescent material light and second device light based diffused light along a same optical path to the light exit of the light generating system. The auxiliary dichroic beam splitter may therefore, especially, be configured to (i) reflect or transmit light having a wavelength selected from the yellow-orange wavelength range, and (ii) transmit or reflect light having a wavelength selected from the blue wavelength range. For example, in embodiments, the auxiliary dichroic beam splitter may be reflective for light having a wavelength selected from the blue wavelength range and transmissive for light having a wavelength selected from the yellow-orange wavelength range. As such, in embodiments, the auxiliary dichroic beam splitter may be configured to (i) reflect (at least part of) the (first and / or second) device light generated diffused light, and (ii) transmit (at least part of) the (first and / or second) device light generated luminescent material light. However, in other embodiments, the auxiliary dichroic beam splitter may be transmissive for light having a wavelength selected from the blue wavelength range and reflective for light having a wavelength selected from the yellow- orange wavelength range. As such, in embodiments, the auxiliary dichroic beam splitter may be configured to (i) transmit (at least part of) the (first and / or second) device light generated diffused light, and (ii) reflect (at least part of) the (first and / or second) device light generated luminescent material light. In embodiments, the term “auxiliary dichroic beam splitter” may refer to two or more auxiliary dichroic beam splitters.

[0050] The light generating system may thus be configured to generate system light comprising one or more of first device light generated system light and second device light generated system light. In embodiments, the first device light generated system light may especially comprise at least part of the first device light based diffused light and at least part of the first device light generated luminescent material light. Analogously, in embodiments, the second device light generated system light may especially comprise at least part of the second device light based diffused light and at least part of the second device light generated luminescent material light. In embodiments, the control system may be configured to control the first light generating arrangement and the second light generating arrangement, such that the system light (comprising the first device light generated system light and / or the second device light generated system light) may be provided. Furthermore, the system light may be white light. Especially, in embodiments, the first device light generating system light and the second device light generated system light may be white light. The term “white light”, and similar terms, herein, are 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.

[0051] In specific embodiments, the first device light generated system light may have a first color point (according to CIE 1931). Analogously, in embodiments, the second device light generated system light may have a second color point (according to CIE 1931). In embodiments, the first color point and the second color point may be within 20 standard deviation, such as within 10 standard deviation, of color matching from the black body locus and within 20 standard deviation, such as within 10 standard deviation, of color matching from each other. Especially, in embodiments, the first color point and the second color point may be within 7 standard deviation of color matching from the black body locus and within 7 standard deviation of color matching from each other. Such embodiments may be beneficial as it ensures that the first device light and the second device light may provide substantially the same type of white system light, therewith preventing drifting of the color point of the system light due to differential aging of one of the light generating arrangements.

[0052] Furthermore, in embodiments, the light generating system may be configured such that the system light may be white light having a correlated color temperature of at least 3500 K, such as at least 5000 K, especially as at least 6500 K, more especially at least 10000 K. Furthermore, in embodiments, the light generating system may be configured such that the system light may be white light having a correlated color temperature of at most 20000 K, such as at most 12000 K. In specific embodiments, the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, like at least 8000 K. Yet further, in embodiments the correlated color temperature (CCT) may be selected from the range of 6000-12000 K, like selected from the range of 7000-12000 K, in combination with a CRI of at least 70, such as at least 80.

[0053] Such embodiments may be beneficial as the light generating system may provide high brightness and high performance white light, which may be especially useful for applications such as projection systems, car front lighting, search lighting, stage lighting (especially for touring, stage, DJ and Club application areas), architectural lighting, and special lighting applications.

[0054] It may be desirable to provide a light generating system for such applications as described above having an improved lifetime, i.e., consistent high performance over an extended period of time. Differential aging of light sources in light generating system may lead to droop and drift in color point of the system light. The above described light generating system may thus provide high performance white light without or with reduced differential aging.

[0055] In embodiments, the light generating system may therefore be configured such that the primary first part of the first device light received by the luminescent material may have a primary first part radiant flux Qu. Additionally, in embodiments, the light generating system may be configured such that the secondary first part of the first device light received by at least one of the one or more diffusers may have a secondary first part radiant flux Qn. Additionally, in embodiments, the light generating system may be configured such that the primary second part of the second device light received by the luminescent material may have a primary second part radiant flux Q21. Additionally, in embodiments, the light generating system may be configured such that the secondary second part of the second device light received by at least one of the one or more diffusers may have a secondary second part radiant flux Q22. Herein, all radiant fluxes may be defined in Watt. The (first and / or second) device light may, in embodiments, be configured to comprise such radiant fluxes as indicated here by the choice of the polarizations of the first device light and the second device light, respectively, in correlation with the choice of the main (polarizing) beam splitter and its axis relative to the laser light polarization directions. In other words, the polarization direction of the device light may be rotated with respect to the polarization direction of the polarizing beam splitter, such that the desired radiant fluxes may be achieved, see also further below. In embodiments, this may be a fixed setting.

[0056] In embodiments, the primary first part radiant flux u, the secondary first part radiant flux 12, the primary second part radiant flux Q21, and the secondary second part radiant flux 22 may be configured so that Qn / Qn and Q21 / Q22 may be individually selected from the range of 2-4, such as from the range of 2.5-3.5, like from the range of 2.8-3.2. Furthermore, in embodiments, the light generating system may be configured such that 0.85<(Qn / Qi2) / ( 2i / 22)<1.15, such as 0.9<(Qn / Qi2) / (Q2i / Q22)<l .1, like 0.95<(Qn / Qi2) / ( 2i / 22)<1.05 applies. Hence, in embodiments, the light generating system may be configured such that (a) the primary first part of the first device light received by the luminescent material may have a primary first part radiant flux Qu, (b) the secondary first part of the first device light received by at least one of the one or more diffusers may have a secondary first part radiant flux Q12, (c) the primary second part of the second device light received by the luminescent material may have a primary second part radiant flux Q21, (d) the secondary second part of the second device light received by at least one of the one or more diffusers may have a secondary second part radiant flux Q22; and (e) 0.9<(Q 1 i / Q 12) / (Q21 / Q22 f 1.1.

[0057] Such embodiments may be beneficial as the first device light and the second device light may thus contribute to the white system light such that first device light generated system light and second device light generated system light comprise white light of substantially the same type. Hence, if one of the first light generating arrangement or the second light generating arrangement would falter, e.g. through differential aging, the output system light would still comprise essentially the same color point. In embodiments, the radiant flux of the different types of light may thus impact each other, i.e., if the radiant flux of one light generating arrangement reduces at a higher rate than the radiant flux of the other light generating arrangement due to differential aging, the latter may be configured to compensate for the former. Especially, in embodiments, the intensity of one light generating arrangement may be changed to compensate for a reduction in intensity of the other light generating arrangement. Therefore, in embodiments, the control system may be configured to control (especially the intensity of) the first device light in dependence of one or more of second device light based diffused light and second device light generated luminescent material light. Especially, in embodiments, if the second device light based diffused light (and / or the second device light generated luminescent material light) reduces in radiant flux, the control system may be configured to control the first device light, such that the radiant flux of the first device light based diffused light (and / or the first device light generated luminescent material light) may compensate for the reduction of the respective radiant flux of the respective second device light. Additionally or alternatively, in embodiments, the control system may be configured to control (especially the intensity of) the second device light in dependence of one or more of first device light based diffused light and first device light generated luminescent material light. Especially, in embodiments, if the first device light based diffused light (and / or the first device light generated luminescent material light) reduces in radiant flux, the control system may be configured to control the second device light, such that the radiant flux of the second device light based diffused light (and / or the second device light generated luminescent material light) may compensate for the reduction of the respective radiant flux of the respective first device light. Hence, in embodiments, the control system may be configured to one or more of

[0058] (a) control the first device light in dependence of one or more of (al) second device light based diffused light and (a2) second device light generated luminescent material light, and

[0059] (b) control the second device light in dependence of one or more of (bl) first device light based diffused light and (b2) first device light generated luminescent material light.

[0060] Furthermore, in embodiments, the control system may be configured to control one or more of a spectral power distribution, the correlated color temperature and the color rendering index of the system light (especially of the first device light generated system light and the second device light generated system light).

[0061] 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.

[0062] Here, in embodiments, the control system may especially be configured to control the first device light and the second device light in dependence of a spectral power distribution of the system light. Therefore, in embodiments, the light generating system (e.g. the control system) may for example comprise a sensor. The sensor may be configured to measure the spectral power distribution of the system light and provide a sensor signal related to the measured spectral power distribution to the control system. The control system may be configured to subsequently control the first device light and or the second device light in dependence of the sensor signal, i.e., in dependence of the spectral power distribution of the system light.

[0063] 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.. Hence, in such embodiments, a user may provide instructions to the control system in dependence of the spectral power distribution of the system light. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0064] 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.

[0065] 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).

[0066] 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.

[0067] Returning to the main beam splitter, in embodiments, the main beam splitter may thus comprise a polarizing beam splitter. In embodiments, the main (polarizing) beam splitter (especially its polarization axis) and the polarizations of the first device light (especially its polarization axis) and the second device light (especially its polarization axis) may be chosen such that the above indicated radiant fluxes may be achieved. Therefore, in specific embodiments, the main beam splitter may comprise a first polarizing beam splitter. The first polarizing beam splitter may be defined as an optical filter that lets light waves of a specific polarization pass through while reflecting light waves of other polarizations, thus splitting an incoming beam of light. Here especially, in embodiments, the first polarizing beam splitter may be a polarizing beam splitter for light having a wavelength in the blue wavelength range. However, in other embodiments, this may not necessarily be the case. The first polarizing beam splitter may therefore comprise a first polarizing beam splitter polarization axis (Ap). The angle the first polarizing beam splitter polarization axis (Ap) makes with the polarization axis of the device light (see further below) may dictate what fraction of elliptically polarized light will be reflected and what fraction will be transmitted by the first polarizing beam splitter. Especially, in embodiments, light having a polarization essentially parallel to the first polarizing beam splitter polarization axis (Ap) may be (fully) reflected by the first polarizing beam splitter, whereas light having a polarization essentially perpendicular to the first polarizing beam splitter polarization axis (Ap) may be (fully) transmitted by the first polarizing beam splitter. Therefore, in embodiments, the first device light, especially when received by the first polarizing beam splitter, may comprise a first device light polarization axis (Ai). Similarly, in embodiments, the second device light, especially when received by the first polarizing beam splitter, may comprise a second device light polarization axis (A2). In general, the system would be configured such that one of the second device light polarization axis (A2) and the first device light polarization axis (Ai) would be essentially parallel to the first polarizing beam splitter polarization axis (Ap), and hence the other one would be essentially perpendicular to the first polarizing beam splitter polarization axis (Ap). As such, the main beam splitter would be configured to substantially reflect (all) of one of the first device light and the second device light and would substantially transmit the other one of the first device light and the second device light. Here, however, in embodiments, for one or more, especially both, of the first device light polarization axis (Ai) and the second device light polarization axis (A2) may apply that they are neither parallel nor perpendicular to the first polarizing beam splitter polarization axis (Ap). As such, in embodiments, part of the first device light may be transmitted and another part of the first device light may be reflected by the main beam splitter. Similarly, in such embodiments, part of the second device light may be transmitted and another part of the second device light may be reflected by the main beam splitter. Hence, in other words, the main (polarizing) beam splitter of the light generating system may be chosen having a specific polarization axis. By varying the polarizations of the first and the second device light, their interaction with the main (polarizing) beam splitter may be changed, i.e., the amount of first device light and second device light being transmitted and / or reflected by the main beam splitter may be varied. Especially, in such embodiments, the ratio of primary first part to secondary first part, and similarly the ratio of primary second part to secondary second part of may be varied, thus resulting in a different radiant flux (as described above) of the respective parts of first and second device light received by the luminescent material and the diffuser(s). Hence, in specific embodiments, the main beam splitter may comprise a first polarizing beam splitter, wherein the first polarizing beam splitter may comprise a first polarizing beam splitter polarization axis (Ap), wherein the first device light received by the first polarizing beam splitter may comprise a first device light polarization axis (Ai) and wherein the second device light received by the first polarizing beam splitter may comprise a second device light polarization axis (A2); wherein for both device light polarization axes (AI,A2) may apply that they may be neither parallel nor perpendicular to the first polarizing beam splitter polarization axis (Ap).

[0068] Especially, in embodiments, the first device light polarization axis (Ai) may have a first angle (0i) with the first polarizing beam splitter polarization axis (Ap). Moreover, in embodiments, the second device light polarization axis (A2) may have a second angle (62) with the first polarizing beam splitter polarization axis (Ap). In embodiments, the first angle (0i) and the second angle (62) may be (individually) selected from the range of 1-89°, such as from the range of 5-85°, like from the range of 20-70°. In further embodiments, 85<(9I+02)<95, such as 88<(9I+92)<92, especially 91+92 = 90°. For example, in embodiments, the first angle (9i) and the second angle (92) may be different, e.g., the first angle (9i) may be 20° and the second angle (92) may be 70°, or vice versa. In another example, in embodiments, the first angle (9i) may be 30° and the second angle (92) may be 60°, or vice versa.

[0069] In embodiments, during a fabrication stage of the light generating system one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter may be configured rotated relative to each other such that the first angle (9i) and the second angle (92) may be (individually) selected from the range of 1-89°. Especially, in embodiments, during the fabrication stage of the light generating system one or more of the first laser bank (comprising the plurality of first light generating devices), the second laser bank (comprising the plurality of second light generating devices), and the first polarizing beam splitter may be configured rotated relative to each other such that the first angle (9i) and the second angle (92) may be (individually) selected from the range of 1-89°. In such embodiments, the first angle (9i) and the second angle (92) may thus be pre-programmed, i.e., during operation the first angle (9i) and the second angle (92) may not change. However, in other embodiments, this may not necessarily be the case, see also further below.

[0070] The first device light and the second device light may in embodiments thus comprise elliptically polarized light. Especially, in (other) embodiments, the first device light (as received by the main beam splitter) may comprise xl% s-polarized light and 100-xl% p- polarized light. Further, in embodiments, the polarization direction of the first device light may be rotated with respect to the polarization direction of the first polarizing beam splitter such that at the first polarizing beam splitter the first device light may be split into zl% s- polarized light and 100-zl% p-polarized light. Further, in embodiments, the second device light (as received by the main beam splitter) may comprise 100-xl% s-polarized light and xl% p-polarized light. Especially, in embodiments, the polarization direction of the second device light may be rotated with respect to the polarization direction of the first polarizing beam splitter such that at the first polarizing beam splitter the second device light may be split into 100-zl% s-polarized light and zl% p-polarized light. Hence, in embodiments, the polarization of the first device light may be correlated to the polarization of the second device light. Herein, especially, in embodiments, xl may be at least 1, such as at least 5, especially at least 10, like at least 30. Further, in embodiments, xl may be at most 99, such as at most 95, especially at most 90, like at most 70. Thus, in embodiments, xl may be selected from the range of l<xl<99, such as from the range of 5<xl<95, like from the range of 10<xl<40, especially from the range of 15<xl<30. Further, in embodiments, zl may be at least 1, such as at least 5, especially at least 10, like at least 30. Yet further, in embodiments, zl may be at most 99, such as at most 95, especially at most 90, like at most 70. Thus, in embodiments, zl may be selected from the range of l<zl<99, such as from the range of 5<zl<95, like from the range of 10<zl<40, especially from the range of 15<zl<30. Hence, in embodiments, the (elliptically polarized) first device light may be split into both p-polarized light and s- polarized light. Similarly, in embodiments, the (elliptically polarized) second device light may also be split both p-polarized light and s-polarized light. Furthermore, in embodiments, one of the first device light and the second device light may be more s-polarized than p- polarized, and hence the other one of the first device light and the second device light may be more p-polarized than s-polarized. For example, in embodiments, xl=40%, i.e., the first device light may comprise 40% p-polarized light and 60% s-polarized light, while the second device light may comprise 60% p-polarized light and 40% s-polarized light. Hence, in embodiments, the first device light may comprise xl% s-polarized light and 100-xl% p- polarized light, the second device light may comprise 100-xl% s-polarized light and xl% p- polarized light; wherein the first device light polarization axis (Ai) may have a first angle (0i) with the first polarizing beam splitter polarization axis (Ap), and wherein the second device light polarization axis (A2) may have a second angle (02) with the first polarizing beam splitter polarization axis (Ap), wherein 0i+02 = 90°; wherein l<xl<99.

[0071] In embodiments, the light generating system may further comprise an actuator. Especially, in embodiments, the light generating system may comprise one or more actuators. The (one or more) actuator(s) may be configured to rotate one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter. Especially, in embodiments, the (one or more) actuator(s) may be configured to rotate one or more of the first laser bank, the second laser bank, and the first polarizing beam splitter. For example, in embodiments, the light generating system may comprise one actuator configured to rotate the first polarizing beam splitter relative to the (static) first light generating arrangement and the (static) second light generating arrangement. In another example, in embodiments, the light generating system may comprise an actuator for each of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter. In such embodiments, the actuators may especially be configured to rotate one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter relative to each other such that the first angle (0i) and the second angle (02) may be (individually) selected from the range of 1-89°. Thus, in embodiments, the actuator may be configured to adjust one or more of the first angle (0i) and the second angle (02) through a rotated orientation of one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter. Hence, in embodiments, the first angle (0i) and the second angle (02) may thus be changed during operation of the light generating system. Therefore, in embodiments, the control system may be configured to control the actuator. Especially, in embodiments, the control system may be configured to individually control the one or more actuators. Therewith, in embodiments, the control system may be configured to maintain a predetermined color point of the system light over time. The control system is described in more detail further below. Hence, in embodiments, the light generating system may comprise an actuator, wherein the actuator may be configured to rotate one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter; wherein the control system may be configured to control the actuator, and wherein the control system may be configured to maintain a predetermined color point of the system light over time. Such embodiments may be beneficial as tunability of the light generating system may be improved. Furthermore, with such embodiments the light generating system may become more user friendly, especially, the light generating system may be adjusted to user preferences in addition to being factory set for reducing the effects of differential aging. Especially, if one of the light generating arrangement were to deter over time due to differential aging, actuation of one or more of the light generating arrangements and the polarizing beam splitter as well as control thereof by the control system may prevent droop in the color point of the system light. Hence, such embodiments of the system may improve the lifetime of the system.

[0072] Hence, in embodiments, the light generating system may have a predetermined color point of the system light. The predetermined color point of the system light may, in embodiments, be maintained (or preserved) through controlling the radiant flux of the first light generating arrangement and the second light generating arrangement. In other embodiments, the predetermined color point of the system light may be maintained (or preserved) through controlling the relative contributions of the first light generating arrangement and the second light generating arrangement to the system light. Control of the relative contributions may, as described above, be achieved through rotation of one or more of the first light generating arrangement, the second light generating arrangement, and the first polarizing beam splitter relative to each other.

[0073] Here below some further embodiments comprising different configurations of the light generating system will be described.

[0074] In embodiments, the luminescent material may be configured in either a transmissive mode or a reflective mode. 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. 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.

[0075] Especially, the luminescent material may be configured in the transmissive mode. In the transmissive mode, it may be relatively easy to have light source light admixed in the luminescent material light, which may be useful for generating the desirable spectral power distribution. In the reflective mode, thermal management may be easier, as a substantial part of the luminescent material may be in thermal contact with a thermally conductive element, like a heatsink or heat spreader. Hence, would any device light escape from the system, in embodiments this may only via transmission through the luminescent material. Similarly, in embodiments, the one or more diffusers may be configured in the transmissive mode or the reflective mode. In embodiments, an example of a diffuser configured in the reflective mode may be a metallic coated glass diffuser showing 95-98% reflectance. Conversely, in embodiments, an example of a diffuser configured in the transmissive mode may be an opal (glass or polymeric) sheet, or a glass or polymeric element with a diffusive coating. Hence, in some embodiments, the luminescent material may be configured in the transmissive mode (and at least one of the one or more diffusers may be configured in the transmissive or in the reflective mode). Especially, in embodiments, the luminescent material may be configured in the transmissive mode and essentially all of the one or more diffusers may be configured in the same one of the transmissive or the reflective mode. In other embodiments, the luminescent material may be configured in the reflective mode (and at least one of the one or more diffusers may be configured in the transmissive of in the reflective mode). Especially, in embodiments, the luminescent material may be configured in the reflective mode and essentially all of the one or more diffusers may be configured in the same one of the transmissive or the reflective mode. In specific embodiments, the following applies: (i) the luminescent material may be configured in the reflective mode, and (ii) at least one of the one or more diffusers may be configured in the reflective mode. Especially, in embodiments, the luminescent material may be configured in the reflective mode and essentially all of the one or more diffusers may be configured in the reflective mode. Such embodiments may be beneficial as the system may be more fail-safe thanks to the reflective configuration for both the luminescent light and the diffused light, by which it can be prevented that direct laser beams emit from the system in case the luminescent component or the diffusing component would fail (e.g. break, fall off, etc.).

[0076] In embodiments, the luminescent material may especially 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. In embodiments, the luminescent body (or “body”) may have lateral dimensions width or length (W or L) or diameter (D) and a thickness or height (H). In embodiments, (i) D>H or (ii) and W>H and / or L>H. In specific embodiments, L<10 mm, such as especially L<5mm, more especially L<3mm, most especially L<2 mm. In specific embodiments, W<10 mm, such as especially W<5mm, more especially W<3mm, most especially W<2 mm. In specific embodiments, H<10 mm, such as especially H<5mm, more especially H<3mm, most especially H<2 mm. In specific embodiments, D<10 mm, such as especially D<5mm, more especially D<3mm, most especially D<2 mm. In specific embodiments, the body may have in embodiments a thickness in the range 50 pm - 1 mm. Especially, the lateral dimensions like length, width, and diameter are at least 2 times, like at least 5 times, larger than the height. 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 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.

[0077] In embodiments, the luminescent material, comprised by the luminescent body, (and optionally one or more of the one or more diffusers) may be configured in thermal contact with a thermally conductive material. For instance, the luminescent material may be configured in thermal contact with a thermally conductive element.

[0078] 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 element may comprise or may 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. The distance may be the distanced between two respective surfaces of the respective elements. The distance may be an average distance. For instance, the two elements may be in physical contact at one or more, such as a plurality of positions, but at one or more, especially a plurality of other positions, the elements are not in physical contact. For instance, this may be the case when one or both elements have a rough surface. When two elements are in thermal contact, they may be in physical contact or may be configured at a short distance of each other, like at maximum 10 pm, such as at maximum 1 mm. When the two elements are configured at a distance from each other, an intermediate material may be configured in between, though in other embodiments, the distance between the two elements may filled with a gas, liquid, or may be vacuum. When an intermediate material is available, the larger the distance, the higher the thermal conductivity may be useful for thermal contact between the two elements. However, the smaller the distance, the lower the thermal conductivity of the intermediate material may be (of course, higher thermal conductive materials may also be used).

[0079] As indicated above, in embodiments, at least one of the one or more diffusers may be configured in the reflective mode. Further, in specific embodiments, at least one of (or even all of) the one or more diffusers may comprise a polarization maintaining diffuser. Especially, in embodiments where the (first and / or second) device light received by the diffuser may be polarized light said diffuser may comprise a polarization maintaining diffuser. In embodiments, such a diffuser may be selected such and the light generating system may be configured such that the depolarization of the diffuser is at maximum 50%, such as at maximum about 25%. In embodiments, the depolarization of diffused device light (relative to the device light irradiating the diffuser) may be not more than about 20%, such as not more than about 10%.

[0080] Furthermore, in embodiments (especially where the at least one of the one or more diffusers may be configured in the reflective mode), the light generating system may comprise a polarization changing element. The polarization changing element may, in embodiments, be configured in an optical path between the main beam splitter and especially the polarization maintaining diffuser. In embodiments, the polarization changing element may thus be configured in a light-receiving relationship with the main beam splitter, i.e. (first and / or second) device light may propagate from the main beam splitter to the polarization changing element. The polarization changing element may, in embodiments, be configured to change the polarization of the incident light. Especially, the polarization changing element may be configured to change linearly polarized light (e.g. s-polarized light or p-polarized light) to circular polarized light (e.g. left-handed polarized light or right-handed polarized light). The polarization changing element may direct the (first and / or second) device light (having the changed polarization) to the one or more polarization maintaining diffusers. Subsequently, the one or more polarization changing diffusers may change the direction of the polarized light (e.g. from right-handed to left-handed circular polarization or vice versa), but the circular polarized light may essentially stay circular polarized light. At least part of the (first and / or second device light based) diffused light, having circular polarization, may then propagate from the one or more polarization maintaining diffusers back to the polarization changing element, and then be converted to (diffused) s-polarized light and / or (diffused) p-polarized light, which may further propagate to the auxiliary dichroic beam splitter. Hence, in embodiments, the at least one of the one or more diffusers may be configured in the reflective mode; the light generating system may further comprise a polarization changing element configured in an optical path between the main beam splitter and the polarization maintaining diffuser.

[0081] In embodiments, the polarization changing element may especially be an element that induces a 90° phase shift between the two orthogonal linear polarization components (s and p) of the light. The most common way is to use birefringent material (birefringent rotators), such as a quarter-wave plate. Hence, in embodiments, the polarization changing element may especially comprise a X / 4 waveplate. As known from the art, a waveplate or retarder is an optical device that alters the polarization state of a light wave travelling through it. A halfwave plate may shift the polarization direction of linearly polarized light (especially from s to p or from p to s polarization), and a quarter-wave plate may convert linearly polarized light into circularly polarized light (and vice versa). Hence, in embodiments, the polarization changing element may comprises a 4 waveplate for one or more wavelengths of the first device light and for one or more wavelengths of the second device light. In this way, p-polarized light can be converted in diffused s-polarized light, and s-polarized light can be converted in diffused p-polarized light. An alternative may be to use the Faraday effect, in which case the phase shift is caused by an applied magnetic field (Faraday rotators). Hence, in embodiments, such phase shift may be the result of any one of birefringent, electro-optical, thermo-optical, magneto-optical or any other principle known in the art.

[0082] In embodiments where the light generating system comprises one (polarization maintaining) diffuser, there may also be one polarization changing element, especially configured in an optical path between the main beam splitter and the (polarization maintaining) diffuser. However, in embodiments where the light generating system comprises more than one (polarization maintaining) diffuser, there may also be more than one polarization changing element. In such embodiments, each polarization changing element may especially be configured in an optical path between the main beam splitter and one of the (polarization maintaining) diffusers. Moreover, in such embodiments one or more of (especially each of) the polarization changing elements may comprise a X / 4 waveplate for one or more wavelengths of the first device light and for one or more wavelengths of the second device light. For example, in embodiments, there may be one (polarization maintaining) diffuser and polarization changing element (especially X / 4 waveplate) subset configured to receive and diffuse at least part of the first device light, and another (polarization maintaining) diffuser and polarization changing element (especially X / 4 waveplate) subset configured to receive and diffuse at least part of the second device light. In other embodiments, essentially all of the (polarization maintaining) diffuser and polarization changing element (especially X / 4 waveplate) subsets may be configured to receive and diffuse at least part of both of the first device light and the second device light.

[0083] Here below a some further specific embodiments of the light generating system are described, where the light generating system especially comprises a first diffuser, a first polarization changing element, a second polarizing beam splitter, a second diffuser, a second polarization changing element, a third polarizing beam splitter, and a fourth polarizing beam splitter.

[0084] In embodiments, the second polarizing beam splitter may be configured downstream of the main beam splitter. Here especially, in embodiments, the main beam splitter may comprise a first polarizing beam splitter. Especially, in embodiments, the main beam splitter may be a first polarizing beam splitter for light having a wavelength in the blue wavelength range. Moreover, in embodiments, the first polarizing beam splitter may be configured in an optical path between the first light generating arrangement and the luminescent material and in an optical path between the second light generating arrangement and the luminescent material. Additionally, in embodiments, the first polarizing beam splitter may also be configured in an optical path between the first light generating arrangement and the second polarizing beam splitter and in an optical path between the second light generating arrangement and the second polarizing beam splitter. Therewith, in embodiments, the second polarizing beam splitter may be configured to direct one or more of at least part of the first device light and at least part of the of the second device light (propagating from the first polarizing beam splitter to the second polarizing beam splitter) to the first diffuser. Additionally, in embodiments, the second polarizing beam splitter may be configured to direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light (propagating from the first diffuser to the second polarizing beam splitter) to the second dichroic beam splitter.

[0085] Further, in embodiments, the first polarization changing element may be configured in an optical path between the second polarizing beam splitter and the first diffuser. The (first and second) polarization changing element and the (first and second) diffuser have been described in more detail above. Especially, the first polarization changing element may comprise an element configured to induce a 90° phase shift in the polarization of incident light, such an element may e.g. be a X / 4 waveplate. Additionally or alternatively, in embodiments, the first diffuser may comprise a polarization maintaining diffuser.

[0086] Yet further, in embodiments, the third polarizing beam splitter may be configured downstream of the second polarizing beam splitter. In embodiments, the third polarizing beam splitter may be configured to direct one or more of at least part of the first device light and at least part of the second device light (propagating from the second polarizing beam splitter to the third polarizing beam splitter) to the second diffuser. Additionally, in embodiments, the third polarizing beam splitter may be configured to direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light (propagating from the second diffuser to the third polarizing beam splitter) to the fourth polarizing beam splitter.

[0087] Further, in embodiments, the second polarization changing element may be configured in an optical path between the third polarizing beam splitter and the second diffuser. Especially, the second polarization changing element may comprise an element configured to induce a 90° phase shift in the polarization of incident light, such an element may e.g. be a X / 4 waveplate. Additionally or alternatively, in embodiments, the second diffuser may comprise a polarization maintaining diffuser.

[0088] Furthermore, in embodiments, the auxiliary dichroic beam splitter may be configured downstream of the first dichroic beam splitter and of the second polarizing beam splitter. Moreover, in embodiments, the auxiliary dichroic beam splitter may be configured to direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light (propagating from the second polarizing beam splitter to the second dichroic beam splitter) to the fourth polarizing beam splitter. Additionally, in embodiments, the auxiliary dichroic beam splitter may be configured to direct at least part of the luminescent material light (propagating from the first dichroic beam splitter to the auxiliary dichroic beam splitter) to the fourth polarizing beam splitter. Further, in embodiments, the fourth polarizing beam splitter may be configured downstream of the second dichroic beam splitter and of the third polarizing beam splitter. The fourth polarizing beam splitter may especially be configured to direct (a) at least part of the first device light based diffused light and / or at least part of the second device light based diffused light, and (b) at least part of the luminescent material light to the light exit.

[0089] Hence, in specific embodiments, the light generating system may comprise a first diffuser, a first polarization changing element, a second polarizing beam splitter, a second diffuser, a second polarization changing element, a third polarizing beam splitter, and a fourth polarizing beam splitter; wherein: (i) the second polarizing beam splitter may be configured downstream of the main beam splitter, wherein the main beam splitter may comprise a first polarizing beam splitter; wherein the second polarizing beam splitter may be configured to (a) direct one or more of at least part of the first device light and at least part of the of the second device light to the first diffuser, and to (b) direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light to the second dichroic beam splitter; (ii) the first polarization changing element may be configured in an optical path between the second polarizing beam splitter and the first diffuser; (iii) the third polarizing beam splitter may be configured downstream of the second polarizing beam splitter; wherein the third polarizing beam splitter may be configured to (a) direct one or more of at least part of the first device light and at least part of the second device light to the second diffuser, and to (b) direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light to the fourth polarizing beam splitter; (iv) the second polarization changing element may be configured in an optical path between the third polarizing beam splitter and the second diffuser; (v) the auxiliary dichroic beam splitter may be configured downstream of the first dichroic beam splitter and of the second polarizing beam splitter; wherein the auxiliary dichroic beam splitter may be configured to (a) direct one or more of at least part of the first device light based diffused light and at least part of the second device light based diffused light to the fourth polarizing beam splitter, and (b) at least part of the luminescent material light to the fourth polarizing beam splitter; and (vi) the fourth polarizing beam splitter may be configured downstream of the auxiliary dichroic beam splitter and of the third polarizing beam splitter, and may be configured to direct (a) at least part of the first device light based diffused light and / or at least part of the second device light based diffused light, and (b) at least part of the luminescent material light to the light exit. In embodiments, the system light may thus comprise a diffused device light component and a luminescent material light component. The diffused device light component may, in embodiments, comprise one or more of the first device light based diffused light and the second device light based diffused light. Similarly, the luminescent material light component may comprise, in embodiments, one or more of the first device light generated luminescent material light and the second device light generated luminescent material light. Therefore, the above specific embodiments may lead to four different propagations of light through the light generating system, which are described in more detail below in the detailed description and with reference to the figures.

[0090] As indicated above, the light generating system comprises a light generating device. A light generating device may especially be configured to generate device light. Especially, the light generating device may comprise a light source. The light source may especially configured to generate light source light. In embodiments, the device light may essentially consist of the device light. In other embodiments, the device light may essentially consist of converted light source light. In yet other embodiments, the device light may comprise (unconverted) light source light and converted light source light. Light source light may be converted with a luminescent material into luminescent material light and / or with an upconverter into upconverted light (see also above). The term “light generating device” may also refer to a plurality of light generating devices which may provide device light having essentially the same spectral power distributions. In specific embodiments, the term “light generating device” may also refer to a plurality of light generating devices which may provide device light having different spectral power distributions.

[0091] 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. 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. 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 activematrix (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). 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). 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.

[0092] In embodiments, the light generating device may comprise a luminescent material. In embodiments, the light generating device may comprise a PC LED. In other embodiments, the light generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device may comprise a laser device, like a laser diode. In embodiments, the light generating device may comprise a superluminescent diode. Hence, in specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.

[0093] The light source may especially be configured to generate light source light having an optical axis (O), (a beam shape,) and a spectral power distribution. The light source light may in embodiments comprise one or more bands, e.g. having band widths as known for lasers. The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device). 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. 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. 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. 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. 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. Instead of the term “solid state light source” also the term “semiconductor-based light source” may be applied. Hence, the term “semiconductor-based light source” may e.g. refer to one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode. Hence, the light generating device may comprise one or more of a light emitting diode (LED), a laser diode, and a superluminescent diode.

[0094] 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.

[0095] 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.

[0096] 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. 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). 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.

[0097] 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. 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).

[0098] 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. 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.

[0099] Further, the system may in embodiments comprise further optics then described above. The term “optics” may especially refer to (one or more) optical elements. Hence, the terms “optics” and “optical elements” may refer to the same items. The optics may include one or more or mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, gratings, dichroics, arrays of one or more of the aforementioned, etc. Alternatively or additionally, the term “optics” may refer to a holographic element or a mixing rod. In embodiments, the optics may include one or more of beam expander optics and zoom lens optics. See further above for examples of optics. In embodiments, the optics may comprise an integrator, like a “Koehler integrator” (or “Kohler integrator”). In specific embodiments, the system may further comprise one or more of integrating optics, collimation optics, and homogenization optics. One or more of them are also depicted in the accompanying drawings. For example, in embodiments, the optics may comprise integrators, such as fly-eye lens array pairs or diffuser plates. Further, in embodiments, the optics may comprise such integrators in combination with further condensing and / or collimating optical components, e.g., integrating rods with a polygonal cross sectional shape such as reflective hollow integrator rods or transmissive solid integrator rods (based on total internal reflection for lateral confinement of a longitudinal propagation of the light).

[0100] The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

[0101] 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. 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. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicate wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

[0102] 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 at least the light generating system.

[0103] BRIEF DESCRIPTION OF THE DRAWINGS

[0104] 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:

[0105] Figs. 1 A-D schematically depict some embodiments and aspects of the (embodiments of) the light generating system; Fig. 2 schematically depicts some (other) embodiments and (other) aspects of the (embodiments of) the light generating system;

[0106] Fig. 3 A-C show some aspects and working principles of (the embodiments of) the light generating system.

[0107] Fig. 4 schematically depicts some application embodiments. The schematic drawings are not necessarily to scale.

[0108] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0109] Fig. 1 schematically depicts a light generating system 1000 comprising a first light generating arrangement 1100, a second light generating arrangement 1200, a luminescent material 200, one or more diffusers 710, a first polarizing beam splitter 1525, dichroic beam splitters 1515,2515, and a control system 300. The light generating arrangements 1100,1200 may each comprise one or more light generating devices 100. Especially, in embodiments, the first light generating arrangement 1100 may comprise a plurality of first light generating devices 110. The first light generating devices 110 may comprise first light sources 10 and may especially be configured to generate first device light 111 having a first peak wavelength (Xpi). Moreover, in embodiments, the first light generating arrangement 1100 may comprise a first laser bank comprising the plurality of first light generating devices 110. Hence, in embodiments, the first light generating devices 110 may comprise first laser diodes. Further, in embodiments, the second light generating arrangement 1200 may comprise a plurality of second light generating devices 120. The second light generating devices 120 may comprise second light sources 20 and may especially be configured to generate second device light 121 having a second peak wavelength (Xp2). Moreover, in embodiments, the second light generating arrangement 1200 may comprise a second laser bank comprising the plurality of second light generating devices 120. Hence, in embodiments, the plurality of second light generating devices 120 may comprise second laser diodes. In embodiments, the first peak wavelength ( pi) and the second peak wavelength ( p2) may be relatively close to each other, especially 0 nm < | pi-Xp2| < 15 nm.

[0110] Further, in embodiments, the luminescent material 200 may be configured in a light receiving relationship (via the main beam splitter 1505) with the first light generating arrangement 1100 and may be configured to convert at least part of the first device light 111 into first device light generated luminescent material light 201a. Additionally, in embodiments, the luminescent material 200 may be configured in a light receiving relationship with the second light generating arrangement 1200 and may be configured to convert at least part of the second device light 121 into second device light generated luminescent material light 201b. Hence, in embodiments, the light generating system 1000 may be configured such that both the first device light 111 and the second device light 121 may be directed to the luminescent material 200 and may thus both contribute to the luminescent material light 201(a,b). Furthermore, in embodiments, the luminescent material 200 may comprise at least a first luminescent material 210 of the type AsBsOn Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al.

[0111] In further embodiments, the luminescent material 200 may be configured in the transmissive mode, not depicted, or in the reflective mode, such as depicted here. Similarly, in embodiments, at least one of the one or more diffusers 710 may be configured in the transmissive mode (such as depicted in Fig. 1 A-1C) or in the reflective mode (such as depicted in Fig. ID and Fig. 2). Especially, in embodiments, the following applies: (i) the luminescent material 200 may be configured in the reflective mode, and (ii) at least one of the one or more diffusers 710 may be configured in the (transmissive or especially) reflective mode. Note that, if the light generating system 1000 comprises a luminescent material 200 or a diffusers 710 configured in the transmissive mode, the light generating system 1000 may (further) comprise one or more reflectors 570 configured to help guide light, such as depicted in Fig. 1A-1C.

[0112] Furthermore, in embodiments, the main beam splitter 1505 may be configured in an optical path between the first light generating arrangement 1100 and the luminescent material 200 and in an optical path between the second light generating arrangement 1200 and the luminescent material 200. As such, in embodiments, the light generating system 1000 may be configured such that the first device light 111 received by the main beam splitter 1505 may comprise polarized light and the second device light 121 received by the main beam splitter 1505 may comprise polarized light. Especially, the main beam splitter 1505 may be configured to direct a primary first part of the first device light 111 to the luminescent material 200 and a secondary first part of the first device light 111 to at least one of the one or more diffusers 710. The respective primary first part and secondary first part may especially depend on the polarization of the first device light 111 and a polarization axis Ap of the main beam splitter, see also further below. Additionally, in embodiments, the main beam splitter 1505 may be configured to direct a primary second part of the second device light 121 to the luminescent material 200 and a secondary second part of the second device light 121 to at least one of the one or more the diffusers 710. The respective primary second part and secondary second part may especially depend on the polarization of the second device light 121 and the polarization axis Ap of the main beam splitter, see also further below. Therefore, in embodiments, the main beam splitter 1505 may comprise one or more of a dichroic beam splitter and a polarizing beam splitter, such as at least a polarizing beam splitter.

[0113] Yet further, in embodiments, a first dichroic beam splitter 1515 may be configured to direct at least part of the first device light 111 or at least part of the second device light 121 to the main beam splitter 1505. Hence, in embodiments, the first dichroic beam splitter 1515 may be configured in a light receiving relationship with one of the light generating device 110 (as depicted here) and the second light generating device 120 (not depicted). Additionally, the first dichroic beam splitter 1515 may be configured to direct at least part of the luminescent material light 20 la, 20 lb to an auxiliary dichroic beam splitter 2515.

[0114] Further, in embodiments, at least one of the one or more diffusers 710 may be configured in a light receiving relationship with the first light generating arrangement 1100. Said diffuser 710 may especially be configured to convert at least part of the secondary first part of the first device light 111 into first device light based diffused light 711a. Similarly, in embodiments, at least one of the one or more diffusers 710 may be configured in a light receiving relationship with the second light generating arrangement 1200. Said diffuser 710 may especially be configured to convert at least part of the secondary second part of the second device light 121 into second device light based diffused light 711b.

[0115] In embodiments, the light generating system 1000 may comprise a single diffuser 710, such as depicted here in fig. 1A-1C. However, in other embodiments, such as depicted in Fig. ID and Fig. 2, the light generating system 1000 may comprise more than one diffusers 710a, 710b.

[0116] Further, in embodiments, the auxiliary dichroic beam splitter 2515 may be configured to direct (a) first device light generated luminescent material light 201a and first device light based diffused light 711a, and (b) second device light generated luminescent material light 201b and second device light based diffused light 711b, along a same optical path to the light exit 1090 of the light generating system 1000. The light exit 1090 may, in embodiments, comprise beam homogenizing optics to provide (homogeneous) system light 1001. The light generating system may, in embodiments, also comprise other additional optics. Especially, in embodiments, the light generating system may comprise beam homogenizing and / or collimating optics 550, lenses 560, and reflectors 570.

[0117] Hence, in embodiments, the light generating system 1000 may be configured to generate system light 1001 comprising one or more of (a) first device light generated system light 1001a comprising at least part of the first device light based diffused light 711a and at least part of the first device light generated luminescent material light 201a, and (b) second device light generated system light 1001b comprising at least part of the second device light based diffused light 711b and at least part of the second device light generated luminescent material light 201b. Especially, the first device light generated system light 1001a and the second device light generated system light 1001b may be white light. Furthermore, in embodiments, the control system 300 may be configured to control the first light generating arrangement 1100 and the second light generating arrangement 1200.

[0118] In embodiments, the first device light generated system light 1001a may have a first color point (according to CIE 1931). Further, in embodiments, the second device light generated system light 1001b may have a second color point (according to CIE 1931). Moreover, in embodiments, the first color point and the second color point may be within 20 (such as within 7) standard deviation of color matching from the black body locus and within 20 (such as within 7) standard deviation of color matching from each other.

[0119] Further, in embodiments, the light generating system 1000 may be configured such that the system light 1001 may be white light having a correlated color temperature of at least 5000 K, such as at least 6500 K.

[0120] In further embodiments, the light generating system 1000 may be configured such that the primary first part of the first device light 111 received by the luminescent material 200 may have a primary first part radiant flux u. Likewise, the light generating system 1000 may be configured such that the secondary first part of the first device light 111 received by at least one of the one or more diffusers 710 may have a secondary first part radiant flux Qn. Similarly, in embodiments, the light generating system 1000 may be configured such that the primary second part of the second device light 121 received by the luminescent material 200 may have a primary second part radiant flux 21. Likewise, the light generating system 1000 may be configured such that the secondary second part of the second device light 121 received by at least one of the one or more diffusers 710 may have a secondary second part radiant flux Q22. Herein all radiant fluxes may be defined in Watt. Furthermore, in embodiments, especially 0.9<(Qn / Qi2) / (Q2i / Q22)<l.l may applies. Hence, if one of the first light generating device 110 and the second light generating device 120 should falter due to aging, the other light generating device 100 of the two may be configured to compensate for the loss, such that the system light 1001 may remain essentially the same (therewith preventing a shift in color point).

[0121] Therefore, in embodiments, the control system 300 may be configured to control the first device light 111 in dependence of one or more of (al) second device light based diffused light 711b and (a2) second device light generated luminescent material light 201b. Additionally or alternatively, in embodiments, the control system 300 may be configured to control the second device light 121 in dependence of one or more of (bl) first device light based diffused light 711a and (b2) first device light generated luminescent material light 201a. Yet further, in embodiments, the control system 300 may be configured to control the first device light 111 and the second device light 121 in dependence of a spectral power distribution of the system light 1001.

[0122] Further, in embodiments, the light generating system may comprise one or more thermally conductive elements 750, such as e.g. heat spreaders. Especially, in embodiments, at least the luminescent material, and optionally the one or more diffusers 710, may be configured on a thermally conductive element 750.

[0123] Fig. IB schematically depicts the light generating system 1000 where only the first light generating arrangement 1100 is configured to provide light, first device light 111 (e.g. when the second light generating device 120 falters due to aging). As a result, in such embodiments, the system light 1001 may consist of first device light generated luminescent material light 201a and first device light based diffused light 711a. Hence, in embodiment, the system light 1001 may consist of first device light generated system light 1001a. Similarly, Fig. 1C schematically depicts the light generating system 1000 where only the second light generating arrangement 1200 is configured to provide light, especially second device light 121 (e.g. when the first light generating device 110 falters due to aging). As a result, in such embodiments, the system light 1001 may consist of second device light generated luminescent material light 201b and second device light based diffused light 711b. Hence, in embodiment, the system light 1001 may consist of second device light generated system light 1001b. Note that the embodiments as depicted in Figs. 1B-1C are extremes. In general, the first light generating device 110 and the second light generating device 120 may cooperatively contribute to the system light 1001(a,b). Fig. ID schematically depicts an embodiments of the light generating system 1000 where the luminescent material 200 and the one or more diffusers 710, here especially a first diffuser 710a and a second diffuser 710b, may be configured in the reflective mode.

[0124] Especially, in such embodiments, at least one of the one or more diffusers 710 may comprise a polarization maintaining diffusor. Furthermore, in such embodiments, the light generating system 1000 may further comprise a polarization changing element 810 configured in an optical path between the main beam splitter 1505 and the polarization maintaining diffusor 710. The polarization changing element 810 may, in embodiments, comprise a X / 4 waveplate for one or more wavelengths of the first device light 111 and for one or more wavelengths of the second device light 121. Especially, in embodiments, the polarization changing element 810 may especially be configured to provide a 90° phase shift in the polarization of light incident on the polarization changing element 810. Furthermore, as depicted here, in embodiment, for each diffuser 710 the light generating system may comprise a polarization changing element 810. Hence, in embodiments, a first polarization changing element 810a may be configured in an optical path between the second polarizing beam splitter 2525 and the first diffuser 710a. Similarly, in embodiments, a second polarization changing element 810b may be configured in an optical path between the second polarizing beam splitter 2525 and the second diffuser 710b. Note that, in embodiments, the first and second diffusers 710a,710b may be essentially the same (type of) diffusers, and may thus be freely interchangeable. Similarly, in embodiments, the first and second polarization changing elements 810a, 810b may be essentially the same (type of) polarization changing elements, and may thus be freely interchangeable.

[0125] Fig. 2 schematically depicts a specific embodiment of the light generating system comprising a first diffuser 710a, a first polarization changing element 810a, a second polarizing beam splitter 2525, a second diffuser 710b, a second polarization changing element 810b, a third polarizing beam splitter 3525, and a fourth polarizing beam splitter 4525. In further embodiments, the second polarizing beam splitter 2525 may be configured downstream of the main beam splitter 1505. In further embodiments, the main beam splitter 1505 may comprise a first polarizing beam splitter 1525. Further, in embodiments, the second polarizing beam splitter 2525 may be configured to (a) direct one or more of at least part of the first device light 111 and at least part of the of the second device light 121 (propagating from the first polarizing beam splitter 1525 to the second polarizing beam splitter 2525) to the first diffuser 710a, and to (b) direct one or more of at least part of the first device light based diffused light 711a and at least part of the second device light based diffused light 711b (propagating from the first diffuser 710a to the second polarizing beam splitter 2525) to the auxiliary dichroic beam splitter 2515. Moreover, in embodiments, the first polarization changing element 810a may be configured in an optical path between the second polarizing beam splitter 2525 and the first diffuser 710a. Especially, the third polarizing beam splitter 3525 may be configured downstream of the second polarizing beam splitter 2525. In further embodiments, the third polarizing beam splitter 3525 may be configured to (a) direct one or more of at least part of the first device light 111 and at least part of the second device light 121 (propagating from the second polarizing beam splitter 2525 to the third polarizing beam splitter 3525) to the second diffuser 710b, and to (b) direct one or more of at least part of the first device light based diffused light 711a and at least part of the second device light based diffused light 711b (propagating from the second diffuser 710b to the third polarizing beam splitter 3525) to the fourth polarizing beam splitter 4525. In further embodiments, the second polarization changing element 810b may be configured in an optical path between the third polarizing beam splitter 3525 and the second diffuser 710b. Further, in embodiments, the second dichroic beam splitter 2515 may be configured downstream of the first dichroic beam splitter 1515 and of the second polarizing beam splitter 2525. Furthermore, in embodiments, the second dichroic beam splitter 2515 may be configured to (a) direct one or more of at least part of the first device light based diffused light 711a and at least part of the second device light based diffused light 711b propagating from the second polarizing beam splitter 2525 to the auxiliary dichroic beam splitter 2515) to the fourth polarizing beam splitter 4525, and (b) at least part of the luminescent material light 20 la, 20 lb (propagating from the first dichroic beam splitter 1515 to the auxiliary dichroic beam splitter 2515) to the fourth polarizing beam splitter 4525. Furthermore, in embodiments, the fourth polarizing beam splitter 4525 may be configured downstream of the auxiliary dichroic beam splitter 2515 and of the third polarizing beam splitter 3525, and may be configured to direct (a) at least part of the first device light based diffused light 711a and / or at least part of the second device light based diffused light 711b, and (b) at least part of the luminescent material light 20 la, 20 lb to the light exit 1090.

[0126] As indicated in the summary, a system as described here may result in four different propagations of light through the light generating system. Here below with reference to Fig. 2, the propagations of light are illustrated.

[0127] Firstly, in embodiments, polarized (blue) first device light 111 may be generated by the first light generating device 110 and may propagate from the first light generating device 110, here especially via (more especially transmitted by) the first dichroic beam splitter 1515 to the main beam splitter 1505. The main beam splitter 1505 may, in embodiments, comprise a polarizing beam splitter 1525 (as described above) configured such that one of p-polarized first device light 111 and s-polarized first device light 111 (here especially s-polarized) is reflected and the other one (here p-polarized) is transmitted by the main beam splitter 1505. In embodiments, one of the reflected part or the transmitted part of the first device light (here especially the transmitted part) may propagate from the main beam splitter 1505 to the luminescent material 200 (as described above and especially configured in the reflective mode), where it may be (at least partially) converted to first device light generated luminescent material light 201a. The first device light generated luminescent material light 201a may, in embodiments, propagate from the luminescent material 200 via, especially transmitted (or reflected, not depicted) by the main beam splitter 1505 to the first dichroic beam splitter 1515. At the first dichroic beam splitter 1515, in embodiments, the (yellow) first device light generated luminescent material light 201a may be directed, especially reflected (or transmitted, not depicted here), such that it may propagate to the auxiliary dichroic beam splitter 2515. At the auxiliary dichroic beam splitter 2515, in embodiments, the (yellow) first device light generated luminescent material light 201a may be directed, especially transmitted (or reflected, not depicted), such that it may propagate to the fourth polarizing beam splitter 4525. The fourth polarizing beam splitter 4525 may subsequently direct, especially transmit (or reflect, not depicted here), the (yellow) first device light generated luminescent material light 201a to the light exit 1090.

[0128] Secondly, in embodiments, polarized (blue) second device light 121 may be generated by the second light generating device 120 and may propagate from the second light generating device 120 (optionally via, especially transmitted by, the first dichroic beam splitter 1515) to the main beam splitter 1505. Similarly as for the first device light 111, the main beam splitter 1505 may, in embodiments, comprise a polarizing beam splitter 1525 configured such that one of p-polarized second device light 121 and s-polarized second device light 121 (here especially p-polarized) is reflected and the other one (here s-polarized) is transmitted by the main beam splitter. In embodiments, one of the reflected part or the transmitted part of the second device light (here especially the reflected part) may propagate from the main beam splitter 1505 to the luminescent material 200, where it may be (at least partially) converted to second device light generated luminescent material light 201b. The second device light generated luminescent material light 201b may then, in embodiments, propagate from the luminescent material 200 to the light exit 1090 in essentially the same manner as described for the first device light generated luminescent material light 201a. Thirdly, in embodiments, the other one of the reflected part or the transmitted part of the first device light (as described for the first propagation of light), here especially the reflected part, may propagate from the main beam splitter 1505 to the second polarizing beam splitter 2525 (as described above), where it may be one of: (A) substantially reflected to the first polarization changing element 810a or (B) substantially transmitted to the third polarizing beam splitter 3525. (A) At the first polarization changing element 810a the linear polarization of the first device light 111 may undergo a 90° phase shift, after which the circular polarized first device light 111 may propagate to the first diffuser 710a. The circular polarized first device light 111 may, in embodiments, be diffused by the (configured in the reflective mode) first (polarization maintaining) diffuser 710a into first device light based diffused light 711a. The first device light based diffused light 711a may again propagate from the first diffuser 710a via the first polarization changing element 810a, thereby again undergoing a 90° phase shift to change the polarization back to a linear polarization, and via (here especially transmitted by) the second polarizing beam splitter 2525 to the auxiliary dichroic beam splitter 2515. At the auxiliary beam splitter 2515, in embodiments, the (blue) first device light based diffused light 711a may be directed, here especially reflected, such that it may propagate to the fourth polarizing beam splitter 4525. The fourth polarizing beam splitter 4525 may subsequently direct, here especially transmit, the (blue) first device light based diffused light 71 la to the light exit 1090. (B) At the third polarizing beam splitter 3525 the first device light 111 may be directed, especially through transmission (not depicted) or reflection (as depicted here) by the third polarizing beam splitter 3525, to the second polarization changing element 810b. At the second polarization changing element 810b the linear polarization of the first device light 111 may undergo a 90° phase shift, after which the circular polarized first device light 111 may propagate to the second diffuser 710b. The circular polarized first device light 111 may, in embodiments, be diffused by the (configured in the reflective mode) second (polarization maintaining) diffuser 710b into first device light based diffused light 711a. The first device light based diffused light 711a may again propagate via the second polarization changing element 810b, thereby again undergoing a 90° phase shift to change the polarization back to a linear polarization, and via the third polarizing beam splitter 3525 to the fourth polarizing beam splitter 4525. At the fourth polarizing beam splitter 4525, in embodiments, the (blue) first device light based diffused light 711a may be directed, especially reflected, such that it may propagate to the light exit 1090. Finally, in embodiments, the other one of the reflected part or the transmitted part of the second device light 121 (as described for the second propagation of light) may propagate from the main beam splitter 1505 to the second polarizing beam splitter 2525 (as described above), where it may be (relative to the third propagation of light) the other one of: (A) substantially reflected to the first polarization changing element 810a or (B) substantially transmitted to the third polarizing beam splitter 3525. The second device light 121 may thus especially be diffused by one of the first diffuser 710a and the second diffuser 710b into second device light based diffused light 711b. The second device light based diffused light 711b may then, in embodiments, propagate from the respective diffuser to the light exit 1090 in essentially the same manner as described for the first device light based diffused light 711a.

[0129] Fig. 3 A schematically depicts some aspects of the different types of device light and the main beam splitter 1505. As indicated above, in embodiments, the main beam splitter 1505 may comprise (at least) a first polarizing beam splitter 1525. In embodiments, the first polarizing beam splitter 1525 may comprise a first polarizing beam splitter polarization axis Ap. Likewise, in embodiments, the first device light 111 received by the first polarizing beam splitter 1525 may comprise a first device light polarization axis Ai. Similarly, in embodiments, the second device light 121 received by the first polarizing beam splitter 1525 may comprise a second device light polarization axis A2. Especially, for both device light polarization axes AI,A2 may apply that, in embodiments, they may be neither parallel nor perpendicular to the first polarizing beam splitter polarization axis Ap. Moreover, in embodiments, the first device light polarization axis Ai may have a first angle 0i with the first polarizing beam splitter polarization axis Ap. Similarly, in embodiments, the second device light polarization axis A2 may have a second angle 02 with the first polarizing beam splitter polarization axis Ap. Especially, in embodiments, the first angle 0i and the second angle 02 may both be unequal to 0° and unequal to 90°. However, in embodiments, the polarization of the first device light 111 and the second device light 121 may yet be orthogonal relative to each other, i.e., 0i+02 = 90°. In embodiments, the first angle 0i and the second angle 02 may be factory set, i.e., in a fabrication stage of the light generating system 1000, the first light generating arrangement 1100, the second light generating arrangement 1200, and the first polarizing beam splitter 1525 may be configured such that the first angle 0i and the second angle 02 are fixed. However, in other embodiments, the first angle 0i and the second angle 02 may be variable, see also further below with Fig. 3B. Furthermore, in embodiments, the first device light 111 (as received by the main beam splitter 1505, especially the first polarizing beam splitter 1525) may comprise xl% s-polarized light and 100-xl% p-polarized light. Especially, in embodiments, the polarization direction of the first device light 111 may be rotated with respect to the polarization direction of the first polarizing beam splitter 1525 such that at the first polarizing beam splitter 1525 the first device light 111 may be split into zl% s-polarized light and 100- zl% p-polarized light. Rotation of the first device light 111 may, in embodiments, be achieved by one or more of a rotated orientation of the first laser bank relative to the first polarizing beam splitter 1525, a rotated orientation of the first polarizing beam splitter 1525 relative to the first laser bank, and a rotated orientation of (a package of individual) first lasers in the first laser bank relative to the first polarizing beam spitter 1525.

[0130] In embodiments, the first device light is elliptically polarized light and the second device light is elliptically polarized light.

[0131] Conversely, in embodiments, the second device light 121 (as received by the main beam splitter 1505, especially the first polarizing beam splitter 1525) may comprise 100-xl% s-polarized light and xl% p-polarized light. Especially, in embodiments, the polarization direction of the second device light 121 may be rotated with respect to the polarization direction of the first polarizing beam splitter 1525 such that at the first polarizing beam splitter 1525 the second device light 121 may be split into 100-zl% s-polarized light and zl% p-polarized light. Rotation of the second device light 121 may, in embodiments, be achieved by one or more of a rotated orientation of the second laser bank relative to the first polarizing beam splitter 1525, a rotated orientation of the first polarizing beam splitter 1525 relative to the second laser bank, and a rotated orientation of (a package of individual) second lasers in the second laser bank relative to the first polarizing beam spitter 1525.

[0132] Furthermore, in embodiments, l<xl<99. In specific embodiments, x=50. Yet further, in specific embodiments, one of the first device light 111 and the second device light 121 may be more s-polarized than p-polarized. Especially, the other one of the first device light 111 and the second device light 121 may be more p-polarized than s-polarized.

[0133] Fig. 3C schematically depicts the above indicated rotations. Especially subfigure I schematically depicts individual rotation of the first laser bank (as a whole) and the second laser bank (as a whole) relative to the first polarizing beam splitter 1525, therewith rendering the first device light polarization axis Ai and the second device light polarization axis A2 both non-parallel and non-perpendicular to the first polarizing beam splitter polarization axis Ap. In subfigure II the same effect is obtained through a rotated orientation of the first lasers in the first laser bank (instead of the whole first laser bank) and the second lasers in the second laser bank (instead of the whole second laser bank) relative to the first polarizing beam splitter 1525. Subfigure III schematically depicts a similar situation to subfigure II, but here only a subset (or partial package) of the first (and second) lasers in the first (and second) laser bank are rotated relative to the first polarizing beam splitter 1525.

[0134] In embodiments, the light generating system may further comprise an actuator. Especially, in embodiments, the light generating system may comprise one or more actuators. Fig. 3B especially schematically depicts a part of the light generating system 1000 comprising actuators 400 for each of the first light generating arrangement 1100, the second light generating arrangement 1200, and the first polarizing beam splitter 1515. In embodiments, the (one or more) actuator(s) 400 may be configured to rotate one or more of the first light generating arrangement 1100 (especially the first laser bank), the second light generating arrangement 1200 (especially the second laser bank), and the first polarizing beam splitter 1515. In embodiments, the actuators 400 may especially be configured to rotate one or more of the first light generating arrangement 1100, the second light generating arrangement 1200, and the first polarizing beam splitter 1515 relative to each other such that the first angle 0i and the second angle 02 may be (individually) selected from the range of 1- 89°. Thus, in embodiments, the actuator 400 may be configured to adjust one or more of the first angle 0i and the second angle 02 through a rotated orientation of one or more of the first light generating arrangement 1100, the second light generating arrangement 1200, and the first polarizing beam splitter 1515. Hence, in embodiments, the first angle 0i and the second angle 02 may thus be changed during operation of the light generating system 1000. Therefore, in embodiments, the control system 300 may be configured to control the actuator 400. Especially, in embodiments, the control system 300 may be configured to individually control the one or more actuators 400. Therewith, in embodiments, the control system 300 may be configured to maintain a predetermined color point of the system light 1001 over time.

[0135] Fig. 4 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. 4 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. 4 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.

[0136] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species". Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. 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. 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.

[0137] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0138] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] Hence, in embodiments the invention provides a light generating system with factory stage rotation of the polarization directions of the light generating arrangements and the polarizing beam splitter.

Claims

CLAIMS:

1. A light generating system (1000) comprising a first light generating arrangement (1100), a second light generating arrangement (1200), a luminescent material (200), one or more diffusers (710), a main beam splitter (1505), dichroic beam splitters (1515,2515), a light exit (1090), and a control system (300); wherein: the first light generating arrangement (1100) comprises a plurality of first light generating devices (110) configured to generate first device light (111) having a first peak wavelength (Xpi); wherein the first light generating arrangement (1100) comprises a first laser bank comprising the plurality of first light generating devices (110); wherein the first light generating devices (110) comprise first laser diodes; the second light generating arrangement (1200) comprises a plurality of second light generating devices (120) configured to generate second device light (121) having a second peak wavelength (kp2); wherein the second light generating arrangement (1200) comprises a second laser bank comprising the plurality of second light generating devices (120); wherein the plurality of second light generating devices (120) comprise second laser diodes; wherein 0 nm < |Xpi-Xp2| < 15 nm; the luminescent material (200) is configured (a) in a light receiving relationship with the first light generating arrangement (1100) and is configured to convert at least part of the first device light (111) into first device light generated luminescent material light (201a), and (b) in a light receiving relationship with the second light generating arrangement (1200) and is configured to convert at least part of the second device light (121) into second device light generated luminescent material light (201b); the light generating system (1000) is configured such that the first device light (111) received by the main beam splitter (1505) comprises polarized light and the second device light (121) received by the main beam splitter (1505) comprises polarized light; wherein the main beam splitter (1505) is configured (a) to direct a primary first part of the first device light (111) to the luminescent material (200) and a secondary first part of the first device light (111) to at least one of the one or more diffusers (710), and (b) to direct a primary second part of the second device light (121) to the luminescent material (200) and asecondary second part of the second device light (121) to at least one of the one or more the diffusers (710); a first dichroic beam splitter (1515) is configured (a) to direct at least part of the first device light (111) or at least part of the second device light (121) to the main beam splitter (1505) and (b) to direct at least part of the luminescent material light (201a, 201b) to an auxiliary dichroic beam splitter (2515); at least one of the one or more diffusers (710) is configured in a light receiving relationship with the first light generating arrangement (1100) and is configured to convert at least part of the secondary first part of the first device light (111) into first device light based diffused light (711a), and at least one of the one or more diffusers (710) is configured in a light receiving relationship with the second light generating arrangement (1200) and is configured to convert at least part of the secondary second part of the second device light (121) into second device light based diffused light (711b); the auxiliary dichroic beam splitter (2515) is configured to direct one or more of (a) first device light generated luminescent material light (201a) and first device light based diffused device light (711a), and (b) second device light generated luminescent material light (201b), and second device light based diffused light (711b), along a same optical path to the light exit (1090) of the light generating system (1000); the light generating system (1000) is configured to generate system light (1001) comprising one or more of (a) first device light generated system light (1001a) comprising at least part of the first device light based diffused light (711a) and at least part of the first device light generated luminescent material light (201a), and (b) second device light generated system light (1001b) comprising at least part of the second device light based diffused light (711b) and at least part of the second device light generated luminescent material light (201b); wherein the first device light generated system light (1001a) and the second device light generated system light (1001b) are white light; and the control system (300) is configured to control the first light generating arrangement (1100) and the second light generating arrangement (1200).

2. The light generating system (1000) according to claim 1, wherein the first device light generated system light (1001a) has a first color point, wherein the second device light generated system light (1001b) has a second color point, wherein the first color point and the second color point are within 20 standard deviation of color matching from the black body locus and within 20 standard deviation of color matching from each other.

3. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) is configured such that the system light (1001) is white light having a correlated color temperature of at least 5000 K.

4. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) is configured such that (a) the primary first part of the first device light (111) received by the luminescent material (200) has a primary first part radiant flux u, (b) the secondary first part of the first device light (111) received by at least one of the one or more diffusers (710) has a secondary first part radiant flux Q 12, (c) the primary second part of the second device light (121) received by the luminescent material (200) has a primary second part radiant flux 21, (d) the secondary second part of the second device light (121) received by at least one of the one or more diffusers (710) has a secondary second part radiant flux 22; and (e)0.9<(Q 1 i / 12) / ( 21 / 22 1. 1.

5. The light generating system (1000) according to any one of the preceding claims, wherein the control system (300) is configured to one or more of (a) control the first device light (111) in dependence of one or more of (al) second device light based diffused light (711b) and (a2) second device light generated luminescent material light (201b), and (b) control the second device light (121) in dependence of one or more of (bl) first device light based diffused light (711a) and (b2) first device light generated luminescent material light (201a).

6. The light generating system (1000) according to any one of the preceding claims, wherein the main beam splitter (1505) comprises a first polarizing beam splitter (1525), wherein the first polarizing beam splitter (1525) comprises a first polarizing beam splitter polarization axis (Ap), wherein the first device light (111) received by the first polarizing beam splitter (1525) comprises a first device light polarization axis (Ai) and wherein the second device light (121) received by the first polarizing beam splitter (1525) comprises a second device light polarization axis (A2); wherein for both device light polarization axes (Ai, A2) applies that they are neither parallel nor perpendicular to the first polarizing beam splitter polarization axis (Ap).

7. The light generating system (1000) according to claim 6, wherein the first device light (111) comprises xl% s-polarized light and 100-xl% p-polarized light, wherein the second device light (121) comprises 100-xl% s-polarized light and xl% p-polarized light; wherein the first device light polarization axis (Ai) has a first angle (0i) with the first polarizing beam splitter polarization axis (Ap), and wherein the second device light polarization axis (A2) has a second angle (02) with the first polarizing beam splitter polarization axis (Ap), wherein 0i + 02 = 90°, and wherein l<xl<99.

8. The light generating system (1000) according to any one of the preceding claims 1-7, wherein the luminescent material (200) is configured in the transmissive mode.

9. The light generating system (1000) according to any one of the preceding claims 1-8, wherein the following applies: (i) the luminescent material (200) is configured in the reflective mode, and (ii) at least one of the one or more diffusers (710) is configured in the reflective mode.

10. The light generating system (1000) according to any one of the preceding claims, wherein at least one of the one or more diffusers (710) comprises a polarization maintaining diffusor.

11. The light generating system (1000) according to claim 10, wherein the at least one of the one or more diffusers (710) is configured in the reflective mode; wherein the light generating system (1000) further comprises a polarization changing element (810) configured in an optical path between the main beam splitter (1505) and the polarization maintaining diffusor (710).

12. The light generating system (1000) according to claim 11, wherein the polarization changing element (810) comprises a X / 4 waveplate for one or more wavelengths of the first device light (111) and for one or more wavelengths of the second device light (121).

13. The light generating system (1000) according to any one of the preceding claims 1-12, comprising a single diffuser (710).

14. The light generating system (1000) according to any one of the preceding claims 1-12, comprising a first diffuser (710a), a first polarization changing element (810a), a second polarizing beam splitter (2525), a second diffuser (710b), a second polarization changing element (810b), a third polarizing beam splitter (3525), and a fourth polarizing beam splitter (4525); wherein: the second polarizing beam splitter (2525) is configured downstream of the main beam splitter (1505), wherein the main beam splitter (1505) comprises a first polarizing beam splitter (1525); wherein the second polarizing beam splitter (2525) is configured to (a) direct one or more of at least part of the first device light (111) and at least part of the of the second device light (121) to the first diffuser (710a), and to (b) direct one or more of at least part of the first device light based diffused light (711a) and at least part of the second device light based diffused light (711b) to the auxiliary dichroic beam splitter (2515); the first polarization changing element (810a) is configured in an optical path between the second polarizing beam splitter (2525) and the first diffuser (710a); the third polarizing beam splitter (3525) is configured downstream of the second polarizing beam splitter (2525); wherein the third polarizing beam splitter (3525) is configured to (a) direct one or more of at least part of the first device light (111) and at least part of the second device light (121) to the second diffuser (710b), and to (b) direct one or more of at least part of the first device light based diffused light (711a) and at least part of the second device light based diffused light (711b) to the fourth polarizing beam splitter (4525); the second polarization changing element (810b) is configured in an optical path between the third polarizing beam splitter (3525) and the second diffuser (710b); the auxiliary dichroic beam splitter (2515) is configured downstream of the first dichroic beam splitter (1515) and of the second polarizing beam splitter (2525); wherein the auxiliary dichroic beam splitter (2515) is configured to (a) direct one or more of at least part of the first device light based diffused light (711a) and at least part of the second device light based diffused light (711b) to the fourth polarizing beam splitter (4525), and (b) direct at least part of the luminescent material light (20 la, 20 lb) to the fourth polarizing beam splitter (4525); and the fourth polarizing beam splitter (4525) is configured downstream of the auxiliary dichroic beam splitter (2515) and of the third polarizing beam splitter (3525), and is configured to direct (a) at least part of the first device light based diffused light (711a) and / or at least part of the second device light based diffused light (711b), and (b) at least part of the luminescent material light (201a, 201b) to the light exit (1090).

15. 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) according to any one of the preceding claims.

Images