Light generating system with CCT tunable laser

Abstract

The invention provides a light generating system (1000) comprising a first light generating device (110), a second light generating device (120), a luminescent material (200), a first optical element (410) and a control system (300), where: the first light generating device (110) is configured to generate blue first device light (111), where the first light generating device (110) comprises one or more of a laser diode and a super light emitting diode; wherein the second light generating device (120) is configured to generate red second device light (121), wherein the second light generating device (120) comprises one or more of a laser diode and a super light emitting diode; a luminescent material (200) is configured downstream of the first light generating device (110), wherein the luminescent material (200) is configured to convert at least a portion of the first device light (111) into luminescent material light (201) having one or more wavelengths in the green-yellow wavelength range; the first optical element (410) is configured to have a light-receiving relationship with the first light-generating device (110) and the luminescent material (200); wherein (i) the first optical element (410) has a controllable wavelength dependent transmission in the blue wavelength range, and / or (ii) the first optical element (410) has a controllable wavelength dependent reflection in the blue wavelength range; the light generating system (1000) is configured to generate system light (1001) comprising one or more of first device light (111), second device light (121), and luminescent material light (201); and the control system (300) is configured to control a spectral power distribution of the system light (1001) by controlling the first optical element (410), where the control system (300) is configured to control a correlated color temperature of the system light (1001) at a value selected from the range of 1800 K to 6500 K, where within the range of 1800 K to 6500 K, the correlated color temperature of the system light (1001) is controllable within a CCT control range of at least 250 K.

Description

Technical Field

[0001] The invention relates to a light generating system. The invention also relates to a lighting device comprising a light generating system. Background Art

[0002] Illumination systems are known in the art. For example, US2009 / 0122530 describes solid-state illumination systems that provide improved color quality and / or color contrast according to US2009 / 0122530. According to US2009 / 0122530, these systems provide total light having a delta chromaticity value for each of fifteen color samples of a color quality scale, which are preselected to provide enhanced color contrast relative to an incandescent light source or a blackbody light source according to a specified value that depends on the color temperature. The illumination systems provided in US2009 / 0122530 may include one or more organic electroluminescent elements, or they may include a plurality of inorganic light emitting diodes, wherein at least two of the inorganic light emitting diodes have different color emission bands. WO2021 / 052900A1 discloses a light generating device, which is configured to generate white device light and includes (i) a first light source, configured to generate blue first light source light, wherein the first light source is a first laser light source; (ii) a first luminescent material, configured to convert a portion of the blue first light source light into first luminescent material light, the first luminescent material light having an emission band with a wavelength in one or more of green and yellow; (iii) an optical filter, configured to optically filter the first luminescent material light into optically filtered first luminescent material light, whereby the optically filtered first luminescent material light is red-shifted relative to the first luminescent material light, and (iv) a second light source, configured to generate red second light source light, wherein the second light source includes a second laser light source. Summary of the invention

[0003] Laser-based light sources have attracted great interest due to their potential to produce relatively high flux from a relatively small light-emitting area. The high brightness of these light sources can facilitate miniaturization and more precise control of light distribution with optical devices. It may also be desirable to have a high-brightness light source for general lighting applications that is tunable in a wide range of color spaces / CCTs with good color rendering. Typically, in order to achieve color tunability, a combination of several sources with different starting color points may be required (e.g., various sources with different phosphors, different primary colors from direct emitters (e.g., RGB), or a combination of these sources). In order to create a high-brightness color-tunable light source, these multiple sources may need to be optically combined with good color mixing without additionally increasing the light collection rate. However, for systems with direct RGB lasers, unless there are unrealistic primary laser wavelength requirements, such as due to the inherent narrow spectral width of the laser line and / or practical limitations, such as certain limited spectral ranges, the optical combination of multiple sources will generally result in a relatively low CRI. In addition, for systems with more than one phosphor converter, the light collection rate tends to increase significantly (such as at least x2 times), which may be undesirable for high-brightness applications. Furthermore, prior art systems may require multi-channel drivers and / or additional color mixing. Furthermore, it may be desirable to use common light sources without the need for specialized equipment.

[0004] Therefore, one aspect of the present invention is to provide an alternative light generating device which preferably further at least partially obviates one or more of the above disadvantages.It may be an object of the present invention to overcome or ameliorate at least one disadvantage of the prior art, or to provide a useful alternative.

[0005] According to a first aspect, the present invention provides a light generating system ("system") comprising a first light generating device, a second light generating device, a luminescent material, a first optical element and a control system. In an embodiment, the first light generating device may be configured to generate a blue first device light (or "first device light"). In contrast, in an embodiment, the second light generating device may be configured to generate a red second device light (or "second device light"). In a further embodiment, the first light generating device may include one or more of a laser diode and a superluminescent diode, in particular a laser diode, or in particular a superluminescent diode. Similarly, in an embodiment, the second light generating device may include one or more of a laser diode and a superluminescent diode, in particular a laser diode, or in particular a superluminescent diode. In an embodiment, the luminescent material may be configured (or "arranged") downstream of the first light generating device, in particular wherein the luminescent material is configured to convert at least a portion of the first device light into luminescent material light. The luminescent material light may in particular have one or more wavelengths in the green-yellow wavelength range. In a further embodiment, the first optical element may be configured to have a light receiving relationship with the first light generating device and the luminescent material, in particular wherein (i) the first optical element has a controllable wavelength-dependent transmission in the blue wavelength range, and / or (ii) the first optical element has a controllable wavelength-dependent reflection in the blue wavelength range. Thus, in an embodiment, the light generating system may be configured to generate system light comprising one or more of the first device light, the second device light and the luminescent material light. In an embodiment, the control system may be configured to control the spectral power distribution of the system light, in particular by controlling the wavelength-dependent transmission of (at least) the first optical element, in particular in an operating mode of the light generating system. In a further embodiment, the control system may be configured to control the correlated color temperature (or "CCT") of the system light, in particular in the operating mode, to a value selected from the range of 1800K to 6500K, in particular wherein within the range of 1800K to 6500K, the correlated color temperature of the system light is controllable within a CCT control range of at least 250K.

[0006] The system of the present invention may provide the benefit that a high brightness light source is provided with a high CRI and this further helps control the correlated color temperature of the system light. In particular, in an embodiment, the system may include a (single) phosphor converter element, a (single) blue laser and a (single) red laser. A red laser having emission in a practically usable wavelength range is used to improve the CRI and provide a color point on the black body locus (BBL) for low CCT. The system of the present invention may facilitate providing a system light with a small etendue and an adjustable CCT, such as adjustability in the range of 2700K to 6500K, while maintaining a high CRI, such as, for example, a CRI of at least 80 or higher.

[0007] In particular, the system light may include a blue first device light, a red second device light and a green-yellow luminescent material light, which may (together) provide a high CRI. In particular, the red second device light may also contribute to a high R9 value (red rendering). Since the first optical element may provide a controllable and wavelength-dependent modification in the blue wavelength range, in particular transmission or in particular reflection, the relative contribution of the blue first device light in the system light may be modified, thereby modifying the correlated color temperature (CCT) of the system light. Furthermore, the relative contribution of the red second device light in the system light may be modified, such as depending on a modification of the relative contribution of the blue first device light, to move towards a specific color point, such as a color point on the BBL. In a specific embodiment, the light generating system of the present invention may include: at least one blue laser; a phosphor conversion element that receives laser pump light and produces white light with high CCT (not necessary on the BBL); an optical device for collecting and pre-collimating the phosphor converted light with partially transmitted blue light; a spectral filtering element placed after the collimating optical device, transmitting green-yellow converted light and, depending on its orientation, having the potential to partially suppress blue laser light; a red laser added / combined to the main optical path of the phosphor converted source; and a component for adjusting the transmission of the phosphor converted blue light, such as by changing the angle of the spectral filtering element relative to the main optical axis.

[0008] In a specific embodiment, the present invention may provide a light generating system, comprising a first light generating device, a second light generating device, a luminescent material, a first optical element and a control system, wherein: the first light generating device is configured to generate blue first device light, wherein the first light generating device comprises one or more of a laser diode and a superluminescent diode, wherein the second light generating device is configured to generate red second device light, wherein the second light generating device comprises one or more of a laser diode and a superluminescent diode; the luminescent material is configured downstream of the first light generating device, wherein the luminescent material is configured to convert at least a portion of the first device light into luminescent material light having one or more wavelengths in the green-yellow wavelength range; the first optical element is configured to be coupled to the first light generating device; The generating device and the luminescent material have a light receiving relationship, wherein (i) the first optical element has a controllable wavelength-dependent transmission in the blue wavelength range, and / or (ii) the first optical element has a controllable wavelength-dependent reflection in the blue wavelength range; the light generating system is configured to generate system light including one or more of the first device light, the second device light and the luminescent material light; and the control system is configured to control the spectral power distribution of the system light by controlling the wavelength-dependent transmission of the first optical element, wherein the control system is configured to control the correlated color temperature of the system light to a value selected from the range of 1800K to 6500K, wherein within the range of 1800 to 6500K, the correlated color temperature of the system light is controllable within a CCT control range of at least 250K.

[0009] Hence, the present invention may provide a light generating system.The light generating system may in particular be configured to provide system light.The light generating system may in particular comprise a first light generating device and a second light generating device.

[0010] In an embodiment, the first light generating device may be configured to generate a blue first device light, i.e., a first device light comprising a (centroid) wavelength in the blue wavelength range. The term "blue light" or "blue emission" particularly refers to light with a wavelength in the range of about 440nm to 495nm (including some purple and cyan hues). Therefore, in an embodiment, the first light generating device may be configured to generate a first device light, wherein the first device light comprises a (centroid) wavelength in the range of about 440nm to 495nm. In a further embodiment, at least 80% of the spectral power of the first device light may fall in the range of 440nm to 495nm, such as at least 90%. In particular, the first light generating device may include a first light source, wherein the first light source is configured to provide a (blue) first device light.

[0011] In a further embodiment, the second light generating device may be configured to generate a red second device light, i.e., a second device light comprising a (centroid) wavelength in the red wavelength range. The term "red light" or "red emission" particularly refers to light with a wavelength in the range of about 620nm to 780nm. Therefore, in an embodiment, the second light generating device may be configured to generate a second device light, wherein the second device light comprises a (centroid) wavelength in the range of about 620nm to 780nm. In a further embodiment, at least 80% of the spectral power of the second device light may fall in the range of 620nm to 780nm, such as at least 90%. In particular, the second light generating device may include a second light source, wherein the second light source is configured to provide a (blue) first device light.

[0012] In an embodiment, the second light generating device may in particular comprise one or more of a laser diode and a superluminescent diode, in particular at least a laser diode, or in particular at least a superluminescent diode. Similarly, in an embodiment, the second light generating device may in particular comprise one or more of a laser diode and a superluminescent diode, in particular at least a laser diode, or in particular at least a superluminescent diode.

[0013] The term "laser" refers in particular to a device that emits light by an optical amplification process based on stimulated emission of electromagnetic radiation. In particular, in an embodiment, the term "laser" may refer to a solid-state laser. In a specific embodiment, the term "laser" or "laser light source" or similar terms may refer to a laser diode (or diode laser).

[0014] Therefore, in an embodiment, the first light generating device (or the second light generating device, in particular the first light source (or the second light source)) may include a laser light source. In an embodiment, the term "laser" or "solid-state laser" may refer to cerium-doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), chromium-doped chrysoberyl (alexandrite) laser, chromium ZnSe (Cr:ZnSe) laser, divalent samarium-doped calcium fluoride (Sm:CaF2) laser, Ce:YAG laser, Er:YAG laser, erbium-doped and co-doped erbium-ytterbium glass laser, F-center laser, holmium YAG (Ho:YAG) laser, Nd:YAG laser, NdCrYAG laser, neodymium-doped calcium yttrium oxyborate Nd:YCa4O(BO3)3 or Nd:YCOB, One or more of neodymium-doped yttrium orthovanadate (Nd:YVO4) lasers, neodymium glass (Nd: glass) lasers, neodymium YLF (Nd:YLF) solid-state lasers, promethium-147-doped phosphate glass (147Pm3+: glass) solid-state lasers, ruby ​​lasers (Al2O3:Cr3+), thulium YAG (Tm:YAG) lasers, titanium sapphire (Ti: sapphire; Al2O3:Ti3+) lasers, calcium fluoride doped with trivalent uranium (U:CaF2) solid-state lasers, ytterbium-doped glass lasers (rods, plates / chips and optical fibers), ytterbium YAG (Yb:YAG) lasers, Yb2O3 (glass or ceramic) lasers, etc.

[0015] In an embodiment, the term "laser" or "solid-state laser" may refer to one or more of semiconductor laser diodes such as GaN, InGaN, AlGaInP, AlGaAs, InGaAsP, lead salts, vertical cavity surface emitting lasers (VCSELs), quantum cascade lasers, hybrid silicon lasers, etc.

[0016] Lasers can be combined with upconverters to achieve shorter (laser) wavelengths. For example, upconversion can be obtained using some (trivalent) rare earth ions, or upconversion can be obtained using nonlinear crystals. Alternatively, lasers can be combined with downconverters (such as dye lasers) to achieve longer (laser) wavelengths.

[0017] As can be derived from the description below, the term "laser light source" may also refer to a plurality of (different or identical) laser light sources. In a specific embodiment, the term "laser light source" may refer to a plurality of N (identical) laser light sources. In an embodiment, N=2 or more. In a specific embodiment, N may be at least 5, such as in particular at least 8. In this way, a higher brightness can be obtained. In an embodiment, the laser light sources may be arranged in a laser group (see also above). In an embodiment, the laser group may include heat dissipation and / or optical devices, such as lenses for collimating the laser. In a further embodiment, the first light generating device may include a single light source. Similarly, in an embodiment, the second light generating device may include a single light source.

[0018] The first laser light source (or the second laser light source) may be configured to generate laser light source light (or "laser"). The light source light may consist essentially of laser light source light. The light source light may also comprise laser light source light of two or more (different or identical) laser light sources. For example, laser light source light of two or more (different or identical) laser light sources may be coupled into a light guide to provide a single light beam comprising laser light source light of two or more (different or identical) laser light sources. In a specific embodiment, the light source light is therefore in particular collimated light source light. In a further embodiment, the light source light is in particular (collimated) laser light source light.

[0019] In an embodiment, the laser light source light may include one or more bands having a bandwidth known to the laser. In a specific embodiment, the band(s) may be relatively sharp line(s), such as having a full width at half maximum (FWHM) in a range of less than 20 nm, such as equal to or less than 10 nm at room temperature (RT). Thus, the light source light may have a spectral power distribution (intensity on an energy scale according to wavelength) that may include one or more (narrow) bands. In particular, in an embodiment, the first light generating device may be configured to provide a first device light having a FWHM ≤ 20 nm (such as ≤ 10 nm), particularly at room temperature, i.e., in an embodiment, the first device light may have a FWHM ≤ 20 nm (such as ≤ 10 nm), particularly at room temperature. In a further embodiment, the second light generating device may be configured to provide a second device light having a FWHM ≤ 20 nm (such as ≤ 10 nm), particularly at room temperature, i.e., in an embodiment, the second device light may have a FWHM ≤ 20 nm (such as ≤ 10 nm), particularly at room temperature.

[0020] The beam (of the light source light) may be a focused or collimated beam of the (laser) light source light. The term "focused" may particularly refer to converging to a small spot. This small spot may be located at the discrete converter region, or (slightly) upstream thereof or (slightly) downstream thereof. In particular, the 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 (side) is substantially not larger than the cross-sectional shape (perpendicular to the optical axis) of the discrete converter region (where the light source light irradiates the discrete converter region). The focusing may be performed with one or more optical devices, such as (focusing) lenses. In particular, two lenses may be applied to focus the laser light source light. The collimation may be performed with one or more (other) optical devices, such as collimating elements, such as lenses and / or parabolic mirrors. In an embodiment, the (laser) light source beam may be relatively highly collimated, such as ≤2° (FWHM) in an embodiment, more particularly ≤1° (FWHM), most particularly ≤0.5° (FWHM). Therefore, ≤2° (FWHM) may be considered as (highly) collimated light source light. Optics may be used to provide (high) collimation (see also above).

[0021] Superluminescent diodes are known in the art. Superluminescent diodes may be indicated as semiconductor devices that may be capable of emitting a wide spectrum of low-coherence light like an LED while having a brightness on the order of a laser diode. For example, US2020192017 indicates that "using current technology, a single SLED is capable of emitting over a bandwidth of, for example, up to 50nm to 70nm in the 800nm ​​to 900nm wavelength range with sufficient spectral flatness and sufficient output power. In the visible range for display applications, i.e., in the 450nm to 650nm wavelength range, a single SLED is capable of emitting over a bandwidth of up to 10 to 30nm using current technology. These emission bandwidths are too small for display or projector applications requiring red (640nm), green (520nm) and blue (450nm) (i.e., RGB) emission." In addition, in the book (multiple) edited by Fabrizio Roccaforte, Mike Leszczynski, first published on August 3, 2020, https: / / doi.org / 10.1002 / 9783527825264.ch9 Chapter 9.3Superluminescent diodes are described in "Edge Emitting Laser Diodes and Superluminescent Diodes" by Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Najda, Thomas Slight, Piotr Perlin. The book (particularly Chapter 9.3) is incorporated herein by reference. It is indicated therein that a superluminescent diode (SLD) is an emitter that combines the features of a laser diode and a light emitting diode. SLD emitters utilize stimulated emission, which means that these devices operate at current densities similar to those of laser diodes. The main difference between LDs and SLDs is that in the latter case the device waveguide can be designed in a special way, preventing the formation of standing waves and lasing. Nevertheless, the presence of the waveguide ensures the emission of a high-quality beam with high spatial coherence of the light, but the light is characterized by simultaneously low temporal coherence” and “Currently, the most successful designs of nitride SLDs are bent, curved or tilted waveguide geometries and tilted facet geometries, while in all cases the front end of the waveguide intersects the device facets in an inclined manner, as shown in Figure 9.10. The tilted waveguide suppresses light reflection from the facets into the waveguide by directing the light outside the lossy non-pumped region of the device chip". Thus, an SLD may in particular be a semiconductor light source in which spontaneously emitted light is amplified by stimulated emission in the active region of the device. Such emission is known as "superluminescence". Superluminescent diodes combine the high power and brightness of laser diodes with the low coherence of conventional light-emitting diodes. The low (temporal) coherence of semiconductor light sources has the advantage of significantly reduced or invisible speckle, and the spectral distribution of the emission is much broader than that of laser diodes, which may be more suitable for lighting applications. In particular, the spectral power distribution of a superluminescent diode may change with varying current. In this way, the spectral power distribution may be controlled, see also, for example, Abdullah A. Alatawi et al., Optics Express, Vol. 26, No. 20, pp. 26355-26364. https: / / doi.org / 10.1364 / OE.26.026355 .

[0022] In an embodiment, the light generating system may comprise a luminescent material. The luminescent material may in particular be arranged downstream of the first light generating device, in particular relative to the first device light, i.e. the luminescent material may be arranged in a light receiving relationship with the first light generating device. In particular, the first light generating device may be configured to provide the first device light along a first device light path, optionally via one or more optical elements, such as transmissive and / or reflective optical elements, and the luminescent material may be (at least partially) arranged in the first device light path.

[0023] The luminescent material may be particularly configured to convert at least a portion of the first device light into luminescent material light. In an embodiment, the luminescent material light may particularly have one or more wavelengths in the green-yellow wavelength range. The term "green light" or "green emission" particularly refers to light with a wavelength in the range of about 495nm to 570nm. The term "yellow light" or "yellow emission" particularly refers to light with a wavelength in the range of about 570nm to 590nm. Therefore, the term "green-yellow light" or "green-yellow emission" may particularly refer to light with a wavelength in the range of (approximately) 495nm to 590nm. Therefore, in an embodiment, the luminescent material may be configured to convert at least a portion of the first device light into luminescent material light, wherein the (centroid) wavelength of the luminescent material light is in the range of 495nm to 590nm. In a further embodiment, at least 80% of the spectral power of the luminescent material light may fall within the range of 495nm to 590nm, such as at least 90%.

[0024] The term "luminescent material" particularly refers to a material that can convert a first device light, in particular blue light, into luminescent material light. Typically, the first device light and the luminescent material light have different spectral power distributions. Therefore, instead of the term "luminescent material", the term "luminescent converter" or "converter" may also be applied. Typically, the luminescent material light has a spectral power distribution at a larger wavelength than the first device light, which is the case in so-called down-conversion. In an embodiment, the "luminescent material" may particularly refer to a material that can convert radiation into, for example, visible light. For example, in an embodiment, the luminescent material may be able to convert blue light into visible light. Thus, when excited with blue light, the luminescent material may emit radiation. Typically, the luminescent material will be a down-converter, i.e., radiation of a short wavelength is converted into radiation with a longer wavelength (λex<λem).

[0025] In an embodiment, the term "luminescence" may refer to phosphorescence. In an embodiment, the term "luminescence" may also refer to fluorescence. Instead of the term "luminescence", the term "emission" may also be applied. Therefore, the terms "first device light" and "luminescent material light" may refer to excitation radiation and emission (radiation), respectively. Similarly, the term "luminescent material" may refer to phosphorescent materials and / or fluorescent materials in an embodiment.

[0026] The term "luminescent material" may also refer to a variety of different luminescent materials. Examples of possible luminescent materials are indicated below. Therefore, in a specific embodiment, the term "luminescent material" may also refer to a luminescent material composition.

[0027] For example, it has been used from A3B5O 12Experiments have been performed with different luminescent materials of the group consisting of Ce. In particular, tests have been performed with the following combinations: (i) a first light generating device having a first centroid wavelength selected from the group consisting of 445 nm, 450 nm, 455 nm and 465 nm, (ii) a second light generating device having a second centroid wavelength selected from the group consisting of 630 nm, 632 nm, 634 nm, 636 nm, 638 nm and 640 nm, and (iii) a second light generating device selected from the group consisting of A3B50 12 : Ce. It will be apparent to those skilled in the art that the selection of the centroid wavelength and phosphor may depend on the desired CCT, CRI and R9. With respect to CCT values ​​in the range of 2700K to 4000K, using a phosphor selected from A3B5O 12 : Ce group, particularly good results were obtained at the indicated centroid wavelengths of the first light generating device and the second light generating device. Therefore, in an embodiment, the luminescent material can be selected from A3B5O 12 :Ce group.

[0028] In an embodiment, the luminescent material may be selected from garnet and nitride, in particular doped with trivalent cerium or divalent europium, respectively. The term "nitride" may also refer to nitrogen oxides or nitrogen silicates, etc. Note that the term "luminescent material" may also refer to a combination of two or more different luminescent materials.

[0029] As indicated above, in a specific embodiment, the luminescent material comprises type A3B5O 12 : Ce, wherein A in an embodiment comprises one or more of Y, La, Gd, Tb and Lu, in particular (at least) one or more of Y, Gd, Tb and Lu, and wherein B in an embodiment comprises one or more of Al, Ga, In and Sc. In particular, A may comprise one or more of Y, Gd and Lu, such as in particular one or more of Y and Lu. In particular, B may comprise one or more of Al and Ga, more in particular at least Al, such as substantially entirely Al. Thus, in particular, a suitable luminescent material may be a garnet material comprising cerium. Embodiments of garnet in particular comprise A3B5O 12Garnet, wherein A comprises at least yttrium or lutetium, and wherein B comprises at least aluminum. Such garnet may be doped with cerium (Ce), praseodymium (Pr) or a combination of cerium and praseodymium; however, in particular with Ce. In particular, B comprises aluminum (Al), however, B may also partially comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), in particular up to about 20% Al, more in particular up to about 10% Al (i.e., the B ions consist essentially of 90 or more mol % Al and 10 or less mol % of one or more of Ga, Sc and In); B may in particular comprise up to about 10% gallium. In another variant, B and O may be at least partially replaced by Si and N. The element A may in particular be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Furthermore, Gd and / or Tb are present in an amount in particular only up to about 20% of A. In a specific embodiment, the garnet luminescent material includes (Y 1-x Lu x )3B5O 12 :Ce, wherein x is equal to or greater than 0 and equal to or less than 1. The term ":Ce" indicates that part of the metal ions in the luminescent material (i.e., in garnet: part of the "A" ions) are replaced by Ce. 1-x Lu x )3Al5O 12 In the case of Ce, part of Y and / or Lu is replaced by Ce. This is known to those skilled in the art. Ce will generally replace A by no more than 10%; typically, the Ce concentration will be in the range of 0.1% to 4%, particularly 0.1% to 2% (relative to A). Assuming 1% Ce and 10% Y, the complete detailed chemical formula may be (Y 0.1 Lu 0.89 Ce 0.01 )3Al5O 12 As known to those skilled in the art, Ce in garnet is substantially or exclusively in the trivalent state.

[0030] In an embodiment, the luminescent material (therefore) comprises A3B5O 12 , in particular wherein up to 10% of the BO may be replaced by Si-N.

[0031] In a further embodiment, A may include one or more of Gd and Lu, and B may include at least 90 at. % Al. In a further embodiment, relative to A, the luminescent material may include 0.1 at. % to 2 at. % of cerium.

[0032] In a further embodiment, the luminescent material may include (Y x1-x2-x3 A' x2 Ce x3 )3(Al y1-y2 B'y2 )5O 12 , where x1 + x2 + x3 = 1, where x3 > 0, where 0 < x2 + x3 ≤ 0.2, where y1 + y2 = 1, where 0 ≤ y2 ≤ 0.2, where A' comprises one or more elements selected from the group consisting of lanthanide elements, and where B' comprises one or more elements selected from the group consisting of Ga, In, and Sc. In an embodiment, x3 is selected from the range of 0.001 to 0.1. In the present invention, particularly x1 > 0, such as > 0.2, e.g., at least 0.8. The garnet with Y can provide a suitable spectral power distribution.

[0033] In a further embodiment, up to 10% of B-O can be replaced by Si-N. Here, B in B-O refers to one or more of Al, Ga, In, and Sc (and O refers to oxygen); in a specific embodiment, B-O can refer to Al-O. As indicated above, in a specific embodiment, x3 can be selected from the range of 0.001 to 0.04. Particularly, this luminescent material can have a suitable spectral distribution (however, see below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (in combination with the first light source light and the second light source light) (and an optical filter). Thus, in a specific embodiment, A can be selected from the group consisting of Lu and Gd. Alternatively or additionally, B can include Ga. Thus, in an embodiment, the luminescent material comprises (Y x1-x2-x3 (Lu,Gd) x2 Ce x3 )3(Al y1-y2 Ga y2 )5O 12 , where Lu and / or Gd can be available. Even more particularly, x3 is selected from the range of 0.001 to 0.1, where 0 < x2 + x3 ≤ 0.1, and where 0 ≤ y2 ≤ 0.1. Further, in a specific embodiment, up to 1% of B-O can be replaced by Si-N. Here, the percentage refers to the number of moles (as known in the art); also see, for example, EP3149108. In a further specific embodiment, the luminescent material comprises (Y x1-x3 Ce x3 )3Al5O 12 , where x1 + x3 = 1, and where 0 < x3 ≤ 0.2, such as 0.001 to 0.1.

[0034] In a specific embodiment, the light generating device can include only the luminescent material, which is selected from the type of garnet comprising cerium. In an even further specific embodiment, the light generating device includes a single type of luminescent material, such as (Y x1-x2-x3 A' x2 Ce x3 )3(Aly1-y2 B’ y2 )5O 12 . Thus, in a specific embodiment, the light generating device includes a luminescent material, wherein at least 85 weight percent (wt.%), and even more particularly at least about 90 weight percent, such as even more particularly at least about 95 weight percent of the luminescent material comprises (Y x1-x2-x3 A’ x2 Ce x3 )3(Al y1-y2 B’ y2 )5O 12 . Here, wherein A’ comprises one or more elements selected from the group consisting of lanthanide elements, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In, and Sc, wherein x1 + x2 + x3 = 1, wherein x3 > 0, wherein 0 < x2 + x3 ≤ 0.2, wherein y1 + y2 = 1, wherein 0 ≤ y2 ≤ 0.2. In particular, x3 is selected from the range of 0.001 to 0.1. Note that in the embodiment, x2 = 0. Alternatively or additionally, in the embodiment, y2 = 0.

[0035] In a specific embodiment, A may particularly include at least Y, and B may particularly include at least Al.

[0036] Alternatively or additionally, the luminescent material may include a luminescent material of type A3Si6N 11 :Ce 3+ , wherein A comprises one or more of Y, La, Gd, Tb, and Lu, such as one or more of La and Y in the embodiment.

[0037] In the embodiment, the luminescent material may alternatively or additionally include MS:Eu 2+ and / or M2Si5N8:Eu 2+ and / or MAlSiN3:Eu 2+ and / or Ca2AlSi3O2N5:Eu 2+etc., wherein M includes one or more of Ba, Sr and Ca, and in particular includes at least Sr in an embodiment. Therefore, in an embodiment, the luminescence may include one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is substantially or only divalent and replaces one or more of the indicated divalent cations. Typically, Eu is present in an amount not greater than 10% of the cations; relative to the (multiple) cations it replaces, it is present in an amount particularly in the range of about 0.5% to 10%, more particularly in the range of about 0.5% to 5%. The term ":Eu" indicates that part of the metal ion is replaced by Eu (in these examples by Eu 2+ For example, assuming that the Eu content in CaAlSiN3:Eu is 2%, the correct chemical formula may be (Ca 0.98 Eu 0.02 )AlSiN3. Divalent europium will generally replace divalent cations, such as the above divalent alkaline earth cations, in particular Ca, Sr or Ba. The material (Ba,Sr,Ca)S:Eu may also be indicated as MS:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M includes calcium or strontium, or calcium and strontium, more particularly calcium in the compound. Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr and Ca). In addition, the material (Ba,Sr,Ca)2Si5N8:Eu may also be indicated as M2Si5N8:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M includes Sr and / or Ba in the compound. In a further specific embodiment, M consists of Sr and / or Ba (excluding the presence of Eu), in particular 50% to 100% (more particularly 50% to 90%) of Ba and 50% to 0% (particularly 50% to 10%) of Sr, such as Ba 1.5 Sr 0.5Si5N8:Eu (i.e., 75% Ba; 25% Sr). Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr and Ca). Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu can also be indicated as MAlSiN3:Eu, wherein M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca); in particular, M in the compound includes calcium or strontium, or calcium and strontium, more particularly calcium. Here, Eu is introduced and replaces at least a portion of M (i.e., one or more of Ba, Sr and Ca). As known to those skilled in the art, Eu in the luminescent materials indicated above is substantially or only in a divalent state.

[0038] In an embodiment, the red light emitting material may include one or more materials selected from the group consisting of (Ba, Sr, Ca) S: Eu, (Ba, Sr, Ca) AlSiN3: Eu, and (Ba, Sr, Ca) 2Si5N8: Eu. In these compounds, europium (Eu) is substantially or only divalent and replaces one or more of the indicated divalent cations. Typically, Eu is present in an amount not greater than 10% of the cations; relative to the (multiple) cations it replaces, it is present in an amount particularly in the range of about 0.5% to 10%, more particularly in the range of about 0.5% to 5%. The term ": Eu" indicates that a portion of the metal ions are replaced by Eu (in these examples by Eu). 2+ For example, assuming that the Eu content in CaAlSiN3:Eu is 2%, the correct chemical formula may be (Ca 0.98 Eu 0.02 )AlSiN 3. The divalent europium will generally replace a divalent cation, such as the above divalent alkaline earth cations, in particular Ca, Sr or Ba.

[0039] As known to the person skilled in the art, Eu in the above indicated luminescent materials is substantially or exclusively in the divalent state.

[0040] The blue light emitting material may include YSO (Y2SiO5:Ce 3+ ) or similar compounds, or BAM (BaMgAl 10 O 17 :Eu 2 + ) or similar compounds.

[0041] The term "luminescent material" herein refers in particular to inorganic luminescent materials. Instead of the term "luminescent material", the term "phosphor" can also be applied. These terms are known to the person skilled in the art.

[0042] Alternatively or additionally, other luminescent materials may also be applied. For example, quantum dots and / or organic dyes may be applied and may optionally be embedded in a transmissive matrix, such as a polymer (eg PMMA or polysiloxane, etc.).

[0043] Quantum dots are small crystals of semiconductor materials, typically with a width or diameter of only a few nanometers. When excited by incident light, quantum dots emit light of a color determined by the size and material of the crystal. Therefore, light of a specific color can be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell, such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium-free quantum dots can also be used, such as indium phosphide (InP) and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2). Quantum dots show very narrow emission bands, so they show saturated colors. In addition, the emission color can be easily adjusted by adapting the size of the quantum dots. Any type of quantum dots known in the art can be used in the present invention. However, for environmental safety and concerns, it may be preferred to use cadmium-free quantum dots or at least quantum dots with very low cadmium content.

[0044] Instead of or in addition to quantum dots, other quantum confinement structures may also be used. In the context of the present application, the term "quantum confinement structure" should be understood as, for example, quantum wells, quantum dots, quantum rods, tripods, tetrapods or nanowires.

[0045] Organic phosphors may also be used.

[0046] Different luminescent materials may have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials may in particular have different color points (or dominant wavelengths).

[0047] As indicated above, other luminescent materials may also be possible. Thus, in a specific embodiment, the luminescent material is selected from the group consisting of: nitrides containing divalent europium, oxynitrides containing divalent europium, silicates containing divalent europium, garnets containing cerium, and quantum structures. The quantum structures may, for example, include quantum dots or quantum rods (or other quantum-type particles) (see above). The quantum structures may also include quantum wells. The quantum structures may also include photonic crystals.

[0048] In an embodiment, the luminescent material may consist of a luminophore. In particular, the luminescent material consists of a luminophore. The luminophore may be a layer, such as a self-supporting layer. The luminophore may also be a coating. The luminophore may also include a luminescent coating on a support (in particular a light-transmitting support in a transmission mode, or a reflective support in a reflection mode). In particular, the luminophore may be substantially self-supporting. In an embodiment, the luminescent material may be provided as a luminophore, such as a luminescent single crystal, a luminescent glass or a luminescent ceramic body. Such a body may be indicated as a "converter body" or a "luminophore". In an embodiment, the luminophore may be a luminescent single crystal or a luminescent ceramic body. For example, in an embodiment, a garnet luminescent material including cerium may be provided as a luminescent single crystal or a luminescent ceramic body. In other embodiments, the luminophore may include a light-transmitting body in which a luminescent material is embedded. For example, the luminophore may include a glass body in which a luminescent material is embedded. Alternatively, the glass itself may be luminescent. In other embodiments, the luminophore may include a polymer body in which a luminescent material is embedded. In an embodiment, the luminophore may be a crystalline or ceramic body or a luminescent material dispersed in another material, such as, for example, a polymer body (also see further below). In further embodiments, at least one of the one or more luminous bodies comprises a ceramic body. In addition, in embodiments, at least one of the one or more luminous bodies comprises (a) type A3B50 12 : Ce luminescent material, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc, and / or (b) type A3Si6N 11 :Ce 3 + A luminescent material, wherein A comprises one or more of Y, La, Ga, Tb and Lu, in particular wherein A comprises one or more of La and Y. Furthermore, in an embodiment, one or more luminophores are single luminophores. Thus, the system may comprise a single luminophore. The luminophore is particularly configured to receive at least a portion of the light of the first device. Thus, in an embodiment, the luminophore is configured downstream of the first light generating device. Furthermore, the luminophore may be particularly configured to have a light receiving relationship with the first light generating device.

[0049] In an embodiment, the luminescent material may be operated in a transmissive mode, i.e. light provided to the luminescent material may substantially enter the luminescent material at a first side (and may optionally be converted), and may leave the luminescent material at a second side, in particular wherein the first side and the second side are arranged at opposite sides of the luminescent material. In a further embodiment, the luminescent material may be operated in a reflective mode, i.e. light provided to the luminescent material may enter the luminescent material at a first side (and may optionally be converted), and may leave the luminescent material at a first side.

[0050] In an embodiment, the light generating system may further comprise a first optical element. The first optical element may in particular be configured to have a light receiving relationship with the first light generating device and the luminescent material, i.e. the first optical element may be configured to receive at least a portion of the (blue) first device light and at least a portion of the luminescent material light. The first optical element may in particular provide a controllable and wavelength-dependent modification of the light provided to the first optical element. In particular, in an embodiment, the first optical element may have a controllable wavelength-dependent transmission in the blue wavelength range. In a further embodiment, the first optical element may have a controllable wavelength-dependent reflection in the blue wavelength range. Thereby, by controlling the wavelength-dependent modification of the blue first device light, in particular via transmission or in particular via reflection, the amount of blue light in the (system) light downstream of the first optical element may be controlled. Thus, the first optical element may facilitate the CCT of the system light by providing a component for controlling the proportion of the blue first device light in the system light.

[0051] As described further below, the CCT may also be influenced by (the power of) the second light generating device, in particular under the control of a control system.

[0052] In a further embodiment, the dichroic filter may be movable, such as tiltable or such as displaceable, relative to the optical axis of the (blue) first device light, in particular wherein the control system is configured to control the movement, such as controlling the position of the dichroic filter. For example, in an embodiment, the light generating system may include an actuator, which is configured to move (such as tilt or such as shift) the first optical element, in particular wherein the control system is configured to control the actuator. In a further embodiment, the wavelength-dependent transmission in the blue wavelength range may depend on the position, such as the tilt angle (α) or such as the displacement (d). Therefore, the control system can be configured to control the position, so that the transmission (or reflection) of the light in the blue wavelength range can be controlled, and thereby the correlated color temperature of the system light can be controlled.

[0053] In an embodiment, such as where the first optical element comprises a dichroic filter, at the first position (p1), the transmission in (at least a portion of) the blue wavelength range is at most 0.5 times the transmission in (at least a portion of) the blue wavelength range at the second position (p2), i.e., relative to the second position (p2), the transmission of blue light can be reduced by a factor of two by moving (such as tilting or such as displacing) the first optical element to the first position (p1). In a further embodiment, at the first position (p1), the transmission in (at least a portion of) the blue wavelength range is at most 0.75 times, in particular at most 0.4 times, such as at most 0.3 times, in particular at most 0.2 times the transmission in (at least a portion of) the blue wavelength range at the second position (d2).

[0054] In an embodiment, such as where the first optical element comprises a dichroic mirror, at the first position (p1), the reflection in (at least a portion of) the blue wavelength range is at most 0.5 times the reflection in (at least a portion of) the blue wavelength range at the second position (p2), i.e., the reflection of blue light can be reduced by a factor of two by moving the first optical element to the first position (p1) relative to the second position (p2). In a further embodiment, at the first position (p1), the reflection in (at least a portion of) the blue wavelength range is at most 0.75 times, in particular at most 0.4 times, such as at most 0.3 times, in particular at most 0.2 times the reflection in (at least a portion of) the blue wavelength range at the second position (d2).

[0055] In an embodiment, the first optical element may comprise a dichroic filter. In particular, in an embodiment, the dichroic filter may be tiltable relative to the optical axis of the (blue) first device light, in particular wherein the control system is configured to control the tilt angle (α). The tilt angle may in particular refer to the angle between (i) a plane defined by the first optical element and (ii) the optical axis of the first device light (when it reaches the first optical element). In a further embodiment, the wavelength-dependent transmission in the blue wavelength range depends on the tilt angle (α). Therefore, the control system may be configured to control the tilt angle (α), whereby the transmission (or reflection) of light in the blue wavelength range may be controlled, and thereby the correlated color temperature of the system light may be controlled. To this end, the control system may control the above-mentioned actuator.

[0056] Similarly, in embodiments, the first optical element may comprise a dichroic mirror (or "dichroic reflector"), in particular wherein the dichroic filter may be tiltable relative to the optical axis of the (blue) first device light, in particular wherein the control system is configured to control the tilt angle (α). In further embodiments, the wavelength-dependent reflection in the blue wavelength range depends on the tilt angle (α).

[0057] In an embodiment, the tilt angle (α) may be controllable in the range of 0° to 90° (relative to the optical axis), such as in the range of 15° to 90°, in particular in the range of 30° to 90°, such as in the range of 45° to 90°. Thus, in an embodiment, the first optical element (in particular the dichroic mirror) may be configured perpendicular to the optical axis and controllable relative to the optical axis with a deviation of up to about 45°. In an embodiment, the tilt of 45° may be a clockwise or counterclockwise tilt.

[0058] In an embodiment in which the first optical element comprises a dichroic filter, at the first tilt angle (α1), the transmission in the blue wavelength range (particularly in at least a portion of the blue wavelength range, or in particular in the entire blue wavelength range) is at most 0.5 times the transmission in the blue wavelength range (such as in at least a portion of the blue wavelength range) at the second tilt angle (α2), i.e., the transmission of blue light can be reduced by a factor of two by tilting the first optical element to the first tilt angle (α1) relative to the second tilt angle (α2). In a further embodiment, at the first tilt angle (α1), the transmission in the blue wavelength range is at most 0.75 times, particularly at most 0.4 times, such as at most 0.33 times, particularly at most 0.25 times, such as at most 0.2 times the transmission in (at least a portion of) the blue wavelength range at the second tilt angle (α2).

[0059] In an embodiment, wherein the first optical element comprises a dichroic mirror, at the first tilt angle (α1), the reflection in (at least a portion of) the blue wavelength range is at most 0.5 times the reflection in (at least a portion of) the blue wavelength range at the second tilt angle (α2), i.e., the reflection of blue light can be reduced by a factor of two by tilting the first optical element to the first tilt angle (α1) relative to the second tilt angle (α2). In a further embodiment, at the first tilt angle (α1), the reflection in (at least a portion of) the blue wavelength range is at most 0.75 times, in particular at most 0.4 times, such as at most 0.3 times, in particular at most 0.2 times, the reflection in (at least a portion of) the blue wavelength range at the second tilt angle (α2). In an embodiment, at least a portion of the blue wavelength range may in particular comprise a range of 440 nm to 495 nm, in particular a range of 440 nm to 480 nm, such as a range of 445 nm to 475 nm.

[0060] In particular, the transmission (or reflection) of the first optical element to light in the green-yellow wavelength range and the red wavelength range may be substantially independent of the tilt angle (α). For example, in an embodiment, the dichroic filter may transmit at least 80% of the second device light and the luminescent material light regardless of the tilt angle (α), such as at least 90%, in particular at least 95%, such as at least 97%.

[0061] In a further embodiment, the dichroic filter may include one or more of a dichroic long pass filter and a dichroic narrow band notch filter, in particular a dichroic long pass filter, or in particular a dichroic narrow band notch filter.

[0062] In an embodiment, the first optical element can be (linearly) displaced, such as relative to the optical axis of the first device light, in particular wherein the control system is configured to control the displacement (d). In a further embodiment, the wavelength-dependent transmission in the blue wavelength range depends on the displacement (d). Thus, the control system can be configured to control the displacement (d), whereby the transmission (or reflection) of the light in the blue wavelength range can be controlled, and thereby the correlated color temperature of the system light can be controlled.

[0063] In an embodiment, the control system may be configured to control the displacement (d), in particular by controlling an actuator, to move the first optical element between the first position (p1) and the second position (p2).

[0064] As indicated above, the control system may control the above-mentioned actuator, which may control the displacement.

[0065] In particular, the transmission (or reflection) of the first optical element to light in the green-yellow wavelength range and the red wavelength range may be substantially independent of the tilt angle (α). For example, in an embodiment, the dichroic filter may transmit at least 80% of the second device light and the luminescent material light regardless of the tilt angle (α), such as at least 90%, in particular at least 95%, such as at least 97%.

[0066] As described above, the light generating system can be configured to generate system light, which includes one or more of the first device light, the second device light, and the luminescent material light. In particular, generally, the system light can include (at least a portion of) the first device light, (at least a portion of) the second device light, and (at least a portion of) the luminescent material light.

[0067] As indicated above, the light generating system may further comprise a control system.The control system may in particular be configured to control one or more of the first light generating device, the second light generating device and the first optical element.

[0068] In an embodiment, the control system may be configured to control the spectral power distribution of the system light, in particular in an operating mode (of the light generating system). In particular, the control system may be configured to control the spectral power distribution by controlling (at least) the first optical element, in particular by controlling the tilt angle α of the first optical element. Thus, the control system may be configured to control the spectral power distribution of the system light by controlling the transmission or reflection of the first optical element in the blue wavelength range.

[0069] In a further embodiment, the control system may be configured to control the correlated color temperature of the system light to a value selected from a correlated color temperature range, such as a range from 1800 K to 6500 K, particularly in an operating mode (of the light generating system). In an embodiment, the correlated color temperature range may include a range of 1800 K to 6500 K. In a further embodiment, the correlated color temperature range may include a range of 2700 K to 6500 K. In a further embodiment, the correlated color temperature range may include a range of 4000 K to 5500 K.

[0070] In particular, in an embodiment, the correlated color temperature of the system light may be controllable within a CCT control range within a correlated color temperature range, such as within a range of 1800K to 6500K. In a further embodiment. The CCT control range may be at least 250K, such as at least 500K, in particular at least 750K, such as at least 1000K. For example, if the CCT control range is 250K, the control system may control the system light to have a first CCT and a second CCT, wherein the first CCT and the second CCT are 250K apart. An example of a CCT control range of at least 250K may be a controllable CCT between 2700K and 2950K, and a CCT control range of at least 1000K may be a controllable CCT between 2700K and 3700K. In a further embodiment, the CCT control range may be at most 2500K, such as at most 2000K, in particular at most 1500K.

[0071] In particular, within the CCT control range, the CRI of the system light may be at least 70, in particular at least 75, such as at least 80, in particular at least 85, i.e., for (substantially) any value of CCT within the CCT control region, the CRI of the system light may be at least 70.

[0072] Similarly, in an embodiment, the system light may have an R9 of at least 0, such as at least 10, particularly at least 20, such as at least 30 within the CCT control range.

[0073] In an embodiment, the light generating system may comprise a second optical element, in particular wherein the second optical element comprises a collimator element. The second optical element may in particular be configured downstream of the luminescent material (and the first light generating device). In a further embodiment, the second optical element may be configured upstream of the first optical element. Thus, the second optical element may be configured to have a light receiving relationship with the first light generating device and the luminescent material, and may be configured to provide collimated light, in particular collimated first device light and collimated luminescent material light, to the first optical element.

[0074] The light generating system may further comprise (other) optics (see also above). The term "optics" may particularly refer to (one or more) (third) optical elements. The optics may comprise one or more mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffraction elements, gratings, dichroics, arrays of one or more of the above, etc. Alternatively or additionally, the term "optics" may refer to a holographic element or a mixing rod. In an embodiment, the optics may comprise one or more of a beam expander optic and a zoom lens optic.

[0075] In an embodiment, the light generating system may further comprise a light mixing chamber. The light mixing chamber may in particular be arranged downstream of the first light generating device. In particular, the light mixing chamber may (also) be arranged upstream of (at least a portion of) the luminescent material. Thus, in an embodiment, the light mixing chamber may be arranged between the first light generating device and the light mixing chamber, in particular along (or "within") the first device light path. In particular, the light mixing chamber may be configured to have a light receiving relationship with the first light generating device and may be configured to provide the (mixed) first device light to the luminescent material.

[0076] The term "light mixing chamber" may herein particularly refer to an optical element, particularly a light guide or particularly an optical chamber, which is configured to mix light from multiple sources, such as to provide a (substantially) uniform spectrum in the far field. The optical chamber may comprise light reflecting walls.

[0077] As described above, the control system may be configured to control the first light generating device.In particular, the control system may be configured to control the first device light provided by the first light generating device by controlling the first light generating device, in particular in an operation mode (of the light generating system).

[0078] For example, in an embodiment, the first centroid wavelength (λ C1 ) may depend on the temperature of the first light generating device. In such an embodiment, the control system may be configured to control the first centroid wavelength (λ) of the first device light by controlling C1 ), such as by controlling the temperature of the first light generating device to control the spectral power distribution of the system light.

[0079] In an embodiment, the first centroid wavelength (λ C1 ) may be controlled by controlling a current through a first light generating device, particularly wherein the first light generating device comprises a solid state device.

[0080] The light generating system includes a plurality of first light generating devices, wherein two or more first light generating devices are configured to generate first device lights having different centroid wavelengths in a blue wavelength range. The control system is configured to control the spectral power distribution of the system light by controlling the radiant flux of the device lights of the two or more first light generating devices. Similarly, in such an embodiment, the light mixing chamber can be configured to have a light receiving relationship with the two or more first light generating devices (particularly the plurality of first light generating devices).

[0081] Similarly, in an embodiment, the control system may be configured to control the second light generating device. In particular, the control system may be configured to control the second device light provided by the second light generating device, in particular in the operating mode (of the light generating system), by controlling the second light generating device. For example, in an embodiment, the control system may be configured to control the flux of the second device light by controlling the second light generating device, such as by controlling the output power of the second light generating device.

[0082] In a further embodiment, the second centroid wavelength (λ C2 ) may depend on the temperature of the second light generating device. In such an embodiment, the control system may be configured to control the second centroid wavelength (λ) of the second device light by controlling C2 ), such as by controlling the temperature of the second light generating device to control the spectral power distribution of the system light.

[0083] In an embodiment, the luminescent material may provide a luminescent material having a light centroid wavelength λ CL In particular, the centroid wavelength λ of the luminescent material light CL It may be selected from the range of 495 nm to 590 nm, such as the range of 520 nm to 590 nm, such as the range of 550 nm to 590 nm, in particular the range of 560 nm to 580 nm.

[0084] In a further embodiment, the first centroid wavelength λ C1In a further embodiment, the first centroid wavelength may be selected from the range of 440nm to 500nm, such as the range of 440nm to 490nm, in particular the range of 440nm to 480nm, such as the range of 450nm to 480nm. In a further embodiment, the first centroid wavelength may be selected from the range of 440nm to 470nm, in particular the range of 445nm to 465nm. In a further embodiment, the first centroid wavelength may be selected from the group comprising 445nm, 450nm, 455nm and 465nm. In a further embodiment, the first centroid wavelength may be 445nm. In a further embodiment, the first centroid wavelength may be 450nm. In a further embodiment, the first centroid wavelength may be 455nm. In a further embodiment, the first centroid wavelength may be 465nm.

[0085] Similarly, in an embodiment, the second centroid wavelength λ C2 In a further embodiment, the second centroid wavelength may be selected from the range of 620nm to 780nm, such as the range of 620nm to 650nm, in particular the range of 630nm to 650nm. In a further embodiment, the second centroid wavelength may be selected from the range of 630nm to 640nm. In a further embodiment, the second centroid wavelength may be selected from the group comprising 630nm, 632nm, 634nm, 636nm, 638nm, 640nm. In a further embodiment, the second centroid wavelength may be 630. In a further embodiment, the second centroid wavelength may be 632nm. In a further embodiment, the second centroid wavelength may be 634nm. In a further embodiment, the second centroid wavelength may be 636. In a further embodiment, the second centroid wavelength may be 638nm. In a further embodiment, the second centroid wavelength may be 640nm.

[0086] In particular, excellent results may be obtained in embodiments wherein the first device light has a first centroid wavelength (λ) selected from the range of 440 nm to 490 nm. C1 ), wherein the second device light has a second centroid wavelength (λ selected from the range of 620 nm to 650 nm C2 ), and wherein the luminescent material light has a luminescent material light centroid wavelength (λ) selected from the range of 560 nm to 580 nm CL ).

[0087] The second device light may be combined with the first device light and the emissive material light to provide system light.

[0088] Therefore, the control system can be configured to control the relative contributions of the first device light, the second device light, and the luminescent material light in the system light. In particular, the control system can adjust the color point of the system light by controlling the relative contributions of the first device light, the second device light, and the luminescent material light in the system light, such as (substantially) changing the CCT of the system light while remaining on the BBL.

[0089] In an embodiment, the first device light and the second device light may be combined upstream of the luminescent material. Thus, in an embodiment, the luminescent material may be transmissive, in particular transparent, or in particular translucent for the second device light. In particular, in an embodiment, the luminescent material may be configured to have a light receiving relationship with the second light generating device. In particular, the second light generating device may be configured upstream of the luminescent material (and the first optical element).

[0090] The (red) second device light may be transmitted through (or reflected by) the luminescent material without being converted, which may result in visible red speckle, which may be undesirable. Therefore, in embodiments in which the second light generating device is configured to provide the (red) second device light to the luminescent material (see below), the second light generating device may comprise a superluminescent diode. Thereby, the (red) speckle may be eliminated.

[0091] In further embodiments, the first device light and the second device light may be combined downstream of the luminescent material, ie, the second device light may be combined with the first device light and the luminescent material light.

[0092] In further embodiments, the first device light and the second device light may be combined downstream of the first optical element.

[0093] In an embodiment, the light generating system may further comprise a beam combiner, in particular one or more beam combiners (such as a plurality of beam combiners). The beam combiner may be in particular configured to combine the first device light and the second device light. In particular, the beam combiner may be configured to combine the first device light, the luminescent material light, and the second device light. In an embodiment, the beam combiner may be selected from the group consisting of a surface scattering diffuser, a volume scattering diffuser, a holographic optical element, a light pipe, a light guide, a Koehler integrator optical device, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, and a polarization beam splitter, in particular selected from the group consisting of a holographic optical element, a light pipe, a Koehler integrator optical device, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, and a polarization beam splitter. In a further embodiment, the beam combiner may in particular comprise a fiber bundle combiner, in particular wherein the fiber bundle combiner is configured to combine the first device light and the second device light.

[0094] In an embodiment, the beam combiner may be configured downstream of the first light generating device (relative to the first device light path) and downstream of the second light generating device (relative to the second device light path of the second device light). In a further embodiment, the beam combiner may be configured upstream of the luminescent material. Alternatively, in a further embodiment, the beam combiner may be configured downstream of the luminescent material. Similarly, in an embodiment, the beam combiner may be configured upstream of the first optical element, while in a further embodiment, the beam combiner may be configured downstream of the first optical element.

[0095] The terms "upstream" and "downstream" refer to the arrangement of items or features relative to the propagation of light from a light generating component (specifically a light source here), wherein, relative to a first position in a light beam from the light generating component, a second position in the light beam closer to the light generating component is "upstream" and a third position in the light beam farther away from the light generating component is "downstream".

[0096] The light generating system may be part of or may be used in, for example, office lighting systems, home application systems, store lighting systems, home lighting systems, accent lighting systems, spotlighting systems, theatre lighting systems, fibre optic application systems, projection systems, self-lighting 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, greenhouse lighting systems, horticultural lighting, digital projection or LCD backlighting. The light generating system (or luminaire) may be part of or may be used in, for example, an optical communication system or a disinfection system.

[0097] In an embodiment, the system light may comprise white light.Thus, in an embodiment, the light generating system may be configured to generate white light, in particular white light with a variable CCT.

[0098] The term "white light" and similar terms herein are known to a person skilled in the art. It may particularly relate to light having a correlated color temperature (CCT) between about 1800K and 20000K, such as between 2000 and 20000K, particularly 2700 to 20000K, typically lighting particularly in the range of about 2000K to 7000K, such as in the range of 2700K and 6500K. In an embodiment, for example for the purpose of backlighting or other purposes, the correlated color temperature (CCT) may particularly be in the range of about 7000K and 20000K. Further, in an embodiment, the correlated color temperature (CCT) is particularly within about 15SDCM (standard deviation of color matching) from the BBL (black body locus), particularly within about 10SDCM from the BBL, even more particularly within about 5SDCM from the BBL.

[0099] In a specific embodiment, the correlated color temperature (CCT) may be selected from the range of 6000 K to 12000 K, such as from the range of 7000 K to 12000 K, such as at least 8000 K. Further, in an embodiment, the correlated color temperature (CCT) may be selected from the range of 6000 K to 12000 K, such as from the range of 7000 K to 12000 K, in particular in combination with a CRI of at least 70.

[0100] 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 nm to 780 nm. In this document, UV may particularly refer to wavelengths selected from the range of 190 nm to 380 nm, such as 200 nm to 380 nm. The terms "light" and "radiation" are used interchangeably herein, unless it is obvious from the context that the term "light" refers only to visible light. Thus, the terms "light" and "radiation" may refer to UV radiation, visible light and IR radiation. In specific embodiments, particularly for lighting applications, the terms "light" and "radiation" refer to (at least) visible light.

[0101] The term "violet light" or "violet emission" refers in particular to light having a wavelength in the range of about 380nm to 440nm. The term "orange light" or "orange emission" refers in particular to light having a wavelength in the range of about 590nm to 620nm. The term "pink light" or "pink emission" refers to light having a blue and red component. The term "cyan" may refer to one or more wavelengths selected from the range of about 490nm to 520nm. The term "amber" may refer to one or more wavelengths selected from the range of about 585nm to 605nm, such as about 590nm to 600nm. The phrase "light having one or more wavelengths in the wavelength range" and similar phrases may specifically indicate that the indicated light (or radiation) has a spectral power distribution having at least one or more intensities at least at these one or more wavelengths in the indicated wavelength range. For example, a solid-state light source emitting blue light will have a spectral power distribution with an intensity at one or more wavelengths in the wavelength range of 440nm to 495nm.

[0102] The term "control" and similar terms particularly refer to at least determining the operation of a behavior or monitoring element. Therefore, "control" and similar terms herein may, for example, refer to applying behavior (determining the operation of a behavior or monitoring element) to an element, such as, for example, measuring, displaying, actuating, opening, shifting, changing temperature, etc. In addition, the term "control" and similar terms may additionally include monitoring. Therefore, the term "control" and similar terms may include applying behavior to an element and applying behavior to an element and monitoring the element. The control of an element may be accomplished using a control system, which may also be indicated as a "controller". The control system and the element may therefore be functionally coupled at least temporarily or permanently. The element may include a control system. In an embodiment, the control system and the element may not be physically coupled. Control may be accomplished via wired and / or wireless control. The term "control system" may also refer to a plurality of different control systems, which may be functionally coupled in particular, and for example, a control system may be a host control system, and one or more other control systems may be slave control systems. The control system may include a user interface or may be functionally coupled to a user interface.

[0103] The control system may also be configured to receive and execute instructions from a remote control. In an embodiment, the control system may be controlled via an application on a device, such as a portable device, such as a smartphone or iPhone, a tablet computer, etc. Thus, the device does not have to be coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0104] Thus, in an embodiment, the control system may (also) be configured to be controlled by an application on a remote device. In such an embodiment, the control system of the lighting system may be a slave control system or a control in slave mode. For example, the lighting system may be identified with a code, in particular with a unique code of the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system, which accesses the lighting system based on the knowledge of the (unique) code (input by a user interface with an optical sensor (e.g. a QR code reader)). The lighting system may also include components for communicating with other systems or devices, such as based on Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX or another wireless technology.

[0105] A system or device or apparatus may perform actions in a "mode" or "operation mode" or "mode of operation" or "operable mode". The term "operable mode" may also be indicated as a "control mode". Similarly, in a method, actions or phases or steps may be performed in a "mode" or "operation mode" or "mode of operation" or "operable mode". This does not exclude that the system or device or apparatus may also be adapted to provide another control mode or multiple other control modes. Similarly, this may not exclude that one or more other modes may be performed before and / or after the execution of the mode.

[0106] However, in embodiments, a control system may be available, which is adapted to provide at least a control mode. If other modes are available, the selection of such a mode may in particular be performed via a user interface, although other options (such as executing a mode according to a sensor signal or a (time) scheme) may also be possible. An operating mode may in embodiments also refer to a system or device or apparatus that can be operated only in a single operating mode (i.e. "on", without further adjustability).

[0107] Therefore, in an embodiment, the control system may be controlled according to 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.

[0108] In yet another aspect, the present invention also provides a lamp or a lamp fixture, comprising a light generating system as defined herein. The lamp fixture may also include a housing, an optical element, a shutter, etc. The lamp or the lamp fixture may also include a housing enclosing the light generating system. The lamp or the lamp fixture may include a light window or a housing opening in the housing, through which the system light may escape from the housing. In yet another aspect, the present invention also provides a projection device, comprising a light generating system as defined herein. In particular, a projection device or a "projector" or an "image projector" may be an optical device that projects an image (or a moving image) onto a surface (such as, for example, a projection screen). The projection device may include one or more light generating systems, such as described herein. Therefore, in one aspect, the present invention also provides a light generating device selected from the following group: a group of lamps, lamps, projector devices, disinfection devices, photochemical reactors, and optical wireless communication devices, the light generating device including a light generating system as defined herein. The light generating device may include a housing or a carrier, which is configured to accommodate or support one or more elements of the light generating system. For example, in an embodiment, the light generating device may include a housing or carrier configured to accommodate or support one or more of the first light generating device, the second light generating device, the luminescent material and the first optical element.

[0109] Instead of the term "lighting device" or "lighting system" and similar terms, the term "light generating device" or "light generating system" (and similar terms) may also be applied. A lighting device or a lighting system may be configured to generate device light (or "lighting device light") or system light ("or lighting system light"). As indicated above, the terms light and radiation may be used interchangeably.

[0110] The lighting system may include a light source. In an embodiment, the system light may include one or more of a light source light and a converted light source light (such as a luminescent material light).

[0111] In a specific embodiment, the term UV radiation may refer to near UV radiation (NUV). Therefore, the term "(N)UV" is also used herein, generally referring to UV, and in a specific embodiment, referring to NUV. In a specific embodiment, the term IR radiation may refer to near IR radiation (NIR). Therefore, the term "(N)IR" is also used herein, generally referring to IR, and in a specific embodiment, referring to NIR. In this article, IR (infrared) may particularly refer to radiation with a wavelength selected from the range of 780nm to 3000nm, such as 780nm to 2000nm, for example up to a wavelength of about 1500nm, such as a wavelength of at least 900nm, but in a specific embodiment, other wavelengths may also be possible. Therefore, the term IR may refer to one or more of near infrared (NIR (or IR-A)) and short wavelength infrared (SWIR (or IR-B)), in particular NIR.

[0112] The term "centroid wavelength" (also denoted as λ C ) is known in the art and refers to the wavelength value at which half of the light energy is at the shorter wavelength and half of the energy is at the longer wavelength; the value is specified in nanometers (nm). It is the wavelength that divides the integral of the spectral power distribution into two equal parts, as in the chemical formula λ C =∑λ*I(λ) / (∑I(λ)), where the summation is over the wavelength range of interest and I(λ) is the spectral energy density (i.e., the integral of the product of wavelength and intensity normalized to the integrated intensity over the emission band). The centroid wavelength can be determined, for example, under operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0113] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying schematic drawings, in which corresponding reference characters indicate corresponding parts, and in which:

[0114] Figures 1A to 1C Embodiments of light generating systems are schematically depicted.

[0115] FIG. 2A to FIG. 3D Further aspects of embodiments of the light generating system are schematically depicted.

[0116] Figure 4 Embodiments of lighting devices are schematically depicted.

[0117] The schematic diagrams are not necessarily drawn to scale. DETAILED DESCRIPTION

[0118] Figures 1A to 1CAn embodiment of a light generating system of the present invention is schematically depicted. In the depicted embodiment, the light generating system 1000 includes a first light generating device 110, a second light generating device 120, a luminescent material 200, and a first optical element 410. In the depicted embodiment, the first light generating device 110 is configured to generate a blue first device light 111, and the second light generating device 120 is configured to generate a red second device light 121. In particular, both the first light generating device 110 and the second light generating device 120 may (each) include one or more of a laser diode and a superluminescent diode. The luminescent material 200 is configured to convert at least a portion of the first device light 111 into luminescent material light 201, and (therefore) is configured downstream of the first light generating device 110. The luminescent material light (201) may have one or more wavelengths in the green-yellow wavelength range. Thus, the light generating system 1000 can be configured to generate system light 1001, which includes one or more of a first device light 111, a second device light 121, and a luminescent material light 201, wherein the first device light 111 includes blue light, wherein the second device light 121 includes red light, and wherein the luminescent material light 201 includes green-yellow light. Thus, the system light 1001 can have an appropriate color mix for a high CRI, such as CRI ≥ 80. In the depicted embodiment, the first optical element 410 is configured to have a light receiving relationship with the first light generating device 110 and the luminescent material 200. In particular, the first optical element 410 can have a controllable wavelength-dependent transmission and / or reflection in the blue wavelength range. For example, in the depicted embodiment, the first optical element 410 includes a dichroic filter 415, wherein the dichroic filter 415 is movable relative to the optical axis O of the first device light 111, such as tiltable ( Figure 1A to Figure 1B ), or such as a displaceable ( Figure 1C ), in particular wherein the wavelength-dependent transmission in the blue wavelength range depends on the position p, such as the tilt angle α. Figure 1A to Figure 1B, the tilt angle α may in particular be the angle between (i) a plane defined by the first optical element 410 and (ii) an optical axis O of the first device light 111 (when it reaches the first optical element 410). In particular, in the depicted embodiment, the light generating system comprises an actuator 430, which is configured to move the first optical element 410. In such an embodiment, the control system 300 may in particular be configured to control the actuator 430. Thus, the amount of blue light in the system light may be adjusted via the first optical element 410, whereby the CCT of the system light may be adjusted. In particular, in an embodiment, the control system 300 may be configured to control the tilt angle α. In a further embodiment, the control system 300 may be configured to control the spectral power distribution of the system light 1001 by controlling the wavelength-dependent transmission (or wavelength-dependent reflection) of (at least) the first optical element 410, in particular in an operating mode (of the light generating system 1000). In a further embodiment, the control system 300 may be configured to control the correlated color temperature of the system light 1001 to a value selected from the range of 1800K to 6500K, in particular in the operating mode (of the light generating system 1000), in particular wherein the system light 1001 is controllable within a CCT control range of at least 250K within the range of 1800K to 6500K.

[0119] In the depicted embodiment, the luminescent material operates in a transmissive mode. In further embodiments, the luminescent material may operate in a reflective mode.

[0120] In a further embodiment, the dichroic filter 415 may include one or more of a dichroic long-pass filter and a dichroic (narrow-band) notch filter and a linear filter (such as a linear variable filter (LVF)), in particular a dichroic long-pass filter, or in particular a dichroic narrow-band notch filter, or in particular a linear variable filter.

[0121] Figure 1A An embodiment is schematically depicted, wherein the light generating system 1000 further comprises a second optical element 420, wherein the second optical element 420 comprises a collimator element. Specifically, in the depicted embodiment, the second optical element 420 is arranged downstream of the luminescent material 200 and the first light generating device 110, and is arranged upstream of the first optical element 410.

[0122] Figure 1B An embodiment is schematically depicted, wherein the light generating system 1000 further comprises a light mixing chamber 450 , which is arranged downstream of the first light generating device 110 and upstream of (at least a portion of) the luminescent material 200 .

[0123] In the depicted embodiment, the luminescent material 200 is arranged downstream of the second light generating device 120, specifically, in a light receiving relationship with the second light generating device 120. Therefore, in the depicted embodiment, the luminescent material 200 can be transmissive for the second device light 121. In particular, in the depicted embodiment, the light generating system 1000 also includes a beam combiner 470, wherein the beam combiner 470 is configured to combine the first device light 111 and the second device light 121. In particular, the beam combiner 470 can include a fiber bundle combiner 460, which is configured to combine the first device light 111 and the second device light 121. In further embodiments, the beam combiner 470 can include a dichroic element, which is configured to combine the first device light 111 and the second device light 121.

[0124] In particular, in the depicted embodiment, a mixture of blue and red laser light enters a light mixing chamber 450, where the luminescent material 200 is excited with the blue laser light, and the red laser light is transmitted and partially scattered. The converted white light is collected and collimated by a second optical element 420, such as a compound parabolic concentrator (CPC), which can be attached to the luminescent material 200. In the depicted embodiment, the (pre-collimated) beam passes through a dichroic long pass filter, where, depending on the angular orientation of the filter and the desired spectral composition, part of the blue transmitted light can be filtered out. Finally, the resulting white beam can be further collimated, such as with a lens.

[0125] Figure 1C An embodiment is schematically depicted, wherein the light generating system 1000 comprises a plurality of first light generating devices 110, wherein the light generating system 1000 further comprises a beam combiner configured to combine first device lights 111 of the plurality of first light generating devices 110. In such an embodiment, in particular two or more first light generating devices 110 may be configured to generate first device lights 111 having different centroid wavelengths in the blue wavelength range. Furthermore, in such an embodiment, the control system 300 may be configured to control the spectral power distribution of the system light 1001 by controlling the radiant flux of the device lights 111 of the two or more first light generating devices 110.

[0126] Therefore, in an embodiment, the light generating system 1000 may include (a) a first beam combiner 470, 471, which is configured to combine the first device light 111 of multiple first light generating devices, and (b) a second beam combiner 470, 472, which is configured to combine the first device light 11 and the second device light 121.

[0127] In a further embodiment, the beam combiner 470 (particularly the first beam combiner 470, 471, or particularly the second beam combiner 470, 472) can be selected from the following group: a surface scattering diffuser, a volume scattering diffuser, a holographic optical element, a light pipe, a light guide, a Kohler integrator optical device, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter and a polarization beam splitter.

[0128] Figure 1C A displacement d of the first optical element 410 is further schematically depicted, with which the first optical element can be moved between a first position p1 and a second position p2. In particular, in embodiments, the wavelength-dependent transmission (or reflection) in the blue wavelength range may be different between the first position p1 and the second position p2. For example, in embodiments, the first optical element 410 may include a patterned linear filter, wherein the optical density of the transmitted blue light varies over the entire length of the filter, and the adjustability is achieved by a linear displacement of the filter.

[0129] Figure 2A The spectrum of the first device light 111 is schematically depicted. Figure 2A The wavelength-dependent transmission of an embodiment of the first optical element 410 in percent (%) of transmission is further schematically depicted versus wavelength λ (in nm). In particular, in the depicted embodiment, the transmission depends on the angle of incidence on the first optical element 410 at 0°, 10°, and 20°, i.e., at tilt angles α of approximately 90°, 80°, and 70°. Thus, with respect to a specific embodiment, the first device light 111 may be substantially transmitted at an angle of incidence of 20° (such as at an angle of incidence of 30°), while the first device light 111 may be substantially blocked at an angle of incidence of 10°. However, even at an angle of incidence of 0°, the second device light 121 and the luminescent material light 201 may be substantially fully transmitted, i.e., at least 90% (such as at least 93%) of the second device light 121 and the luminescent material light 201 may be transmitted by the first optical element regardless of the tilt angle α.

[0130] In particular, Figure 2A The schematic diagram shows how the blue laser content in the system light 1001 can be changed by using the first optical element 410. Specifically, Figure 2A It is shown that the transmission of a dichroic longpass filter can be changed depending on the angle of incidence of the incident light; as the angle of incidence increases, the transmission edge of the filter shifts toward shorter wavelengths. By bringing the edge of the filter normal incidence close to the excitation laser wavelength and varying the filter angle relative to the optical axis of light propagation, the amount of blue light in the resulting spectrum can be adjusted, theoretically in the range of 0% to 95% relative to the initial intensity.

[0131] Figure 2BSchematically depicts the spectral power distribution of the system light 1001 in terms of intensity I (au) versus wavelength λ (in nm), indicating the first centroid wavelength λ of the first device light 111 C1 , the second centroid wavelength λ of the second device light 121 C2 and the light emitting material light centroid wavelength λ of the light emitting material light 201 C2 In particular, in the depicted embodiment, the first device light 111 has a first centroid wavelength λ selected from the range of 440 nm to 480 nm. C1 , wherein the second device light 121 has a second centroid wavelength λ selected from the range of 620 nm to 650 nm C2 , and wherein the luminescent material light 201 has a luminescent material light centroid wavelength λ selected from the range of 520nm to 590nm CL , such as selected from the range of 550nm to 590nm.

[0132] In particular, Figure 2B Schematically depicted are the results of spectral simulations using practically available blue and red laser wavelengths and a Gd-doped YAG ceramic phosphor. Depending on the blue content in the spectrum, a wide CCT range of 2700K to 6500K can be covered, with the red laser intensity being adjusted to produce a color point on the BBL. A red laser wavelength of 638nm was chosen because relatively cheap high-power lasers (>5W) are practically available in this wavelength range >637nm. For blue, 465nm was chosen as the longest blue wavelength of commercial laser diodes. Shorter blue wavelengths may be more conducive to higher absorption of the YAG phosphor. However, (relatively) longer blue wavelengths may also have a positive impact on the CRI.

[0133] Figure 2CSchematically depicted is a spectral power distribution of system light 1001 provided by an embodiment of a light generating system 1001, wherein the light generating system 1000 comprises at least two first light generating devices 110, and wherein the first optical element 410 comprises a long pass filter, in particular a long pass filter having a controllable edge position, such as by controlling the angle α (see above). In particular, in the depicted embodiment, one of the at least two first light generating devices 110 is configured to provide a first device light 111 having a centroid wavelength of about 455 nm to more efficiently excite the luminescent material, while another of the at least two first light generating devices 110 is configured to provide a first device light 111 having a centroid wavelength in the line of about 465 nm, thereby contributing to CRI improvement. In this case, the application of the long pass filter can be controlled to set the edge position at or above ˜460 nm to set the total amount of transmitted blue light for the initial color point. The color point tunability can also be affected by electronically adjusting the amount of laser power from two separate blue laser channels. Thus, in the depicted embodiment, one of the at least two first light generating devices 110 can provide the first device light 111 that is partially converted into the luminescent material light 201, while the rest of the first device light 111 is blocked by the long pass filter, while the first device light 111 provided by the other first light generating device 110 of the at least two first light generating devices 110 is substantially not converted by the luminescent material 200 and can mostly pass through the long pass filter. Thus, the amount of blue light in the system light 1001 can be controlled by controlling the other first light generating device 110 of the at least two first light generating devices 110.

[0134] In further embodiments, a narrow band notch filter may also be used instead of a long pass filter, such as with a band rejection at or near 465 nm. In such embodiments, the rejection band and the transmission variation may (also) be controlled as a function of the angle of incidence.

[0135] In addition, color point tunability without mechanical adjustment can also be achieved using the effect of wavelength shift of the laser diode emission wavelength according to temperature. Typical values ​​for wavelength shift are ~1nm / 10°C, where the emission shifts to longer wavelengths as the temperature increases. By using a filter with sharp transition edges and adjusting the temperature of the laser diode (e.g., using a heating element), the amount of transmitted blue laser light passing through the dichroic filter can be adjusted over a wide range. Therefore, in an embodiment, the centroid wavelength λ of the first device light 111 is C1 may depend on the temperature of the first light generating device 110, wherein the control system 300 is configured to control the centroid wavelength λ of the first device light 111 by controlling C1, in particular by controlling the temperature of the first light generating device 110 to control the spectral power distribution of the system light 1001 .

[0136] Similarly, pulse width modulation (PWM) can be used to shift the centroid wavelength, in particular while (substantially) maintaining the average flux. Using pulse width modulation, the temperature of the light generating device, in particular its junction temperature, can also be efficiently controlled. Therefore, in an embodiment, the control system 300 can be configured to control the centroid wavelength λ of the first device light 111 by controlling the pulse frequency of the first light generating device 110. C1 To control the spectral power distribution of the system light 1001.

[0137] FIG. 3A to FIG. 3D Schematically depicting how the CRI and R9 values ​​of the system light 1001 vary depending on the (centroid) wavelength of the (blue) first device light 111 in an embodiment. The longest wavelength within the practical range studied may be preferred in order to provide a high CRI over a wide CCT range. For example, with a centroid wavelength of about 465 nm, a CRI of 90 may be achieved for a CCT in the range of about 4000K to about 5500K.

[0138] In particular, Figure 3A Relative intensity I versus wavelength λ (in nm) for blue light sources with centroid wavelengths of 457 nm, 460 nm, 463 nm and 465 nm are schematically depicted.

[0139] Figure 3B The CRI and CCT (in K) of a combination of blue light sources with centroid wavelengths of 457 nm, 460 nm, 463 nm, and 465 nm or two blue light sources with centroid wavelengths of 567 nm and 465 nm are schematically depicted. Thus, depending on the selected centroid wavelength of the first device light 111, a high CRI, such as about 80, in particular above 85, or even above 90, can be obtained within a large CCT control range.

[0140] Thus, in an embodiment, the first device light may have a first centroid wavelength λ of at least 457 C1 , such as at least 460, in particular at least 463, such as at least 465.

[0141] In a further embodiment, the CCT control range may include at least 500K, such as at least 1000K, in particular at least 1500K within the range of 1800K to 6500K, such as within the range of 2700K to 6500K.

[0142] Figure 3CThe intensity I (in arbitrary units (au)) versus the CCT (in K) of blue light sources with centroid wavelengths of 457, 460, 463 and 465 nm or a combination of two blue light sources with centroid wavelengths of 457 and 465 nm is schematically depicted.

[0143] Figure 3D R9 versus CCT (in K) for blue light sources with centroid wavelengths of 457, 460, 463, and 465 nm or a combination of two blue light sources with centroid wavelengths of 457 and 465 nm are schematically depicted.

[0144] Figure 4 An embodiment of a luminaire 2 comprising the above-described light generating system 1000 is schematically depicted. Reference numeral 301 indicates a user interface, which may be functionally coupled with a control system 300, which control system 300 consists of or is functionally coupled to the light generating system 1000. FIG. 3 also schematically depicts an embodiment of a lamp 1 comprising the light generating system 1000. Reference numeral 3 indicates a projector device or a projector system, which may be used to project an image, such as on a wall, which may also comprise the light generating system 1000. Thus, FIG. 3 schematically depicts an embodiment 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 described herein. In an embodiment, such a lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, or an optical wireless communication device. Light of the lighting device escaping from the lighting device 1200 is indicated with reference numeral 1201. The lighting device light 1201 may be substantially composed of the system light 1001, and thus in a specific embodiment may be the system light 1001. Reference numeral 1300 refers to a space, such as a room. Reference numeral 1305 refers to a floor, and reference numeral 1310 refers to a ceiling; reference numeral 1307 refers to a wall.

[0145] The term "plurality" means two or more.

[0146] The term "substantially" or "substantially" and similar terms herein will be understood by those skilled in the art. The term "substantially" or "substantially" may also include embodiments with "entirely", "completely", "entirely", etc. Therefore, in embodiments, the adjective substantially or substantially may also be removed. Where applicable, the term "substantially" or the term "substantially" may also relate to 90% or higher, such as 95% or higher, in particular 99% or higher, even more particularly 99.5% or higher, including 100%.

[0147] The term "comprise" also includes embodiments wherein the term "comprises" means "consisting of.

[0148] The term "and / or" specifically refers to one or more items mentioned before and after "and / or". For example, the phrase "item 1 and / or item 2" and similar phrases may refer to one or more of item 1 and item 2. The term "comprising" may refer to "consisting of" in an embodiment, but may also refer to "comprising at least the defined species and optionally one or more other species" in another embodiment.

[0149] Furthermore, the terms first, second, third, etc. in the description and claims are used to distinguish similar elements and not necessarily to describe a sequential order 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 those described or illustrated herein.

[0150] An apparatus, device or system may be described herein during operation. As will be apparent to one skilled in the art, the present invention is not limited to methods of operation or apparatus, device or system in operation.

[0151] 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.

[0152] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0153] The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those specified in a claim. Unless the context clearly requires otherwise, throughout the description and claims, the words "comprise", "comprising", etc. should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to".

[0154] The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

[0155] The invention can 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 implemented by one and the same item of hardware. The fact that certain measures are listed in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In a further aspect, the invention (therefore) provides a software product which, when run on a computer, is capable of implementing (one or more embodiments of) the method described herein.

[0156] The present invention also provides a control system that can control a device, apparatus or system, or can perform the method or process described herein. Furthermore, the present invention also provides a computer program product that, when running on a computer that is functionally coupled to or composed of a device, apparatus or system, controls one or more controllable elements of such a device, apparatus or system.

[0157] The invention also applies to an apparatus, device or system comprising one or more characterizing features described in the description and / or shown in the attached drawings. The invention also relates to a method or process comprising one or more characterizing features described in the description and / or shown in the attached drawings.

[0158] The various aspects discussed in this patent can be combined to provide additional advantages. In addition, those skilled in the art will appreciate that the embodiments can be combined, and more than two embodiments can also be combined. In addition, some features can form the basis for one or more divisional applications.

Claims

1. A light generating system (1000), comprising a first light generating device (110), a second light generating device (120), a luminescent material (200), a first optical element (410) and a control system (300), wherein: The first light generating device (110) is configured to generate a blue first device light (111), wherein the first light generating device (110) includes one or more of a laser diode and a superluminescent diode; wherein the second light generating device (120) is configured to generate a red second device light (121), wherein the second light generating device (120) includes one or more of a laser diode and a superluminescent diode; The luminescent material (200) is arranged downstream of the first light generating device (110), wherein the luminescent material (200) is arranged to convert at least a portion of the first device light (111) into luminescent material light (201), the luminescent material light (201) having one or more wavelengths in the green-yellow wavelength range; The first optical element (410) is configured to have a light receiving relationship with the first light generating device (110) and the luminescent material (200); wherein (i) the first optical element (410) has a controllable wavelength-dependent transmission in a blue wavelength range, and / or (ii) the first optical element (410) has a controllable wavelength-dependent reflection in the blue wavelength range; The light generating system (1000) is configured to generate system light (1001), the system light (1001) comprising one or more of the first device light (111), the second device light (121) and the luminescent material light (201); The control system (300) is configured to control the spectral power distribution of the system light (1001) by controlling the first optical element (410), wherein the control system (300) is configured to control the correlated color temperature of the system light (1001) to a value selected from the range of 1800K to 6500K, wherein within the range of 1800K to 6500K, the correlated color temperature of the system light (1001) is controllable within a CCT control range of at least 250K; and The light generating system (1000) further comprises a plurality of first light generating devices (110), wherein two or more of the first light generating devices (110) are configured to generate first device light (111) having different centroid wavelengths within the blue wavelength range, wherein the control system (300) is further configured to control the spectral power distribution of the system light (1001) by controlling the radiant flux of the device light (111) of the two or more first light generating devices (110).

2. A light generating system (1000) according to claim 1, wherein the first optical element (410) includes a dichroic filter (415), wherein the dichroic filter (415) is movable relative to the optical axis of the first device light (111), wherein the control system (300) is configured to control the position of the dichroic filter (415), and wherein (i) the wavelength-dependent transmission in the blue wavelength range depends on the position, or wherein (ii) the wavelength-dependent reflection in the blue wavelength range depends on the position.

3. The light generating system (1000) of claim 2, wherein the dichroic filter (415) comprises one or more of: a dichroic long pass filter, a dichroic narrow band notch filter, and a linear variable filter.

4. A light generating system (1000) according to any one of the preceding claims 2 to 3, wherein the dichroic filter (415) is tiltable relative to the optical axis, wherein the control system (300) is configured to control a tilt angle (α) of the dichroic filter (415), and wherein (i) the wavelength-dependent transmission in the blue wavelength range depends on the tilt angle (α), or wherein (ii) the wavelength-dependent reflection in the blue wavelength range depends on the tilt angle (α).

5. The light generating system (1000) according to any of the preceding claims, further comprising a second optical element (420), wherein the second optical element (420) comprises a collimator element, wherein the second optical element (420) is (a) configured downstream of the luminescent material (200) and the first light generating device (110), and (b) configured upstream of the first optical element (410), and wherein the luminescent material (200) is operated in a transmission mode.

6. The light generating system (1000) according to any of the preceding claims, further comprising a light mixing chamber (450), which is arranged downstream of the first light generating device (110) and upstream of at least a portion of the luminescent material (200).

7. The light generating system (1000) according to any one of the preceding claims, wherein the first centroid wavelength (λ C1 ) depends on the temperature of the first light generating device (110), wherein the control system (300) is configured to control the first centroid wavelength (λ) of the first device light (111) by C1 ) to control the spectral power distribution of the system light (1001).

8. The light generating system (1000) according to any of the preceding claims, wherein the different centroid wavelengths in the blue wavelength range comprise a centroid wavelength (λ ) selected from the range of 445 nm to 465 nm. C1 ) and a centroid wavelength (λ) selected from the range of 450 nm to 480 nm C1 ).

9. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent material (200) comprises a luminescent material of type A3B50. 12 :Ce light-emitting material, wherein A includes one or more of Y, La, Gd, Tb and Lu, and wherein B includes one or more of Al, Ga, In and Sc.

10. The light generating system (1000) of claim 9, wherein A comprises one or more of Gd and Lu, and wherein B comprises at least 90 at. % Al.

11. A light generating system (1000) according to any of the preceding claims, wherein the luminescent material (200) is transparent or translucent to a second device light (121), wherein the luminescent material (200) is configured to have a light receiving relationship with the second light generating device (120).

12. The light generating system (1000) of claim 11, further comprising a beam combiner (470), wherein the beam combiner is configured to combine the first device light (111) and the second device light (121), and wherein the beam combiner (470) is selected from the group consisting of: a holographic optical element, a light pipe, a Koehler integrator optical device, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, a polarization beam splitter, and a fiber bundle combiner (460).

13. The light generating system (1000) according to any one of the preceding claims, wherein the CCT control range comprises a range of at least 500K within the range of 1800K to 6500K.

14. The light generating system (1000) according to any one of the preceding claims, wherein the first device light (111) has a first centroid wavelength (λ) selected from the range of 440 nm to 490 nm. C1 ), wherein the second device light (121) has a second centroid wavelength (λ) selected from the range of 620 nm to 650 nm C2 ), and wherein the luminescent material light (201) has a luminescent material light centroid wavelength (λ) selected from the range of 560 nm to 580 nm CL ).

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

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