Light generation system with a CCT tunable laser

Abstract

The present invention provides a light-generation system 1000 comprising a first light-generation device 110, a second light-generation device 120, a luminescent material 200, a first optical element 410, and a control system 300, wherein the first light-generation device 110 is configured to generate blue first device light 111, the first light-generation device 110 comprising one or more of a laser diode and a superluminescent diode, the second light-generation device 120 is configured to generate red second device light 121, the second light-generation device 120 comprising one or more of a laser diode and a superluminescent diode, the luminescent material 200 is configured downstream of the first light-generation device 110, 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 a green-to-yellow wavelength range, and the first optical element 410 controls the first light-generation device 110 and and a light-receiving relationship with the luminescent material 200, wherein (i) the first optical element 410 has a controllable wavelength-dependent transmittance in a blue wavelength range, and / or (ii) the first optical element 410 has a controllable wavelength-dependent reflectance in a blue wavelength range, the light-generation system 1000 is configured to generate system light 1001 including 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, and the control system 300 is configured to control the correlated color temperature of the system light 1001 to a value selected from a range of 1800 to 6500K, and the correlated color temperature of the system light 1001 is controllable over a CCT control range of at least 250K within the range of 1800 to 6500K.

Description

[Technical Field]

[0001] The present invention relates to a light-generating system. The invention further relates to a lighting device comprising said light-generating system. [Background technology]

[0002] Lighting systems are known in the art. For example, US 2009 / 0122530 describes a solid-state lighting system that provides improved color quality and / or color contrast (according to US 2009 / 0122530). The system provides total light with a delta chroma value for each of 15 color samples of a preselected color quality scale according to a specified value that depends on color temperature (according to US 2009 / 0122530), so as to provide improved color contrast compared to an incandescent or blackbody light source. The lighting system provided in US 2009 / 0122530 may include one or more organic electroluminescent elements or may include multiple inorganic light-emitting diodes, at least two of which have emission bands of different colors. WO2021 / 052900A1 discloses a light-generating device configured to generate white device light, the light-generating device having: (i) a first light source configured to generate blue first light source light, the first light source being 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 having an emission band having wavelengths 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, the optically filtered first luminescent material light being red-shifted relative to the first luminescent material light; and (iv) a second light source configured to generate red second light source light, the second light source comprising a second laser light source. Summary of the Invention [Problem to be solved by the invention]

[0003] Laser-based light sources have attracted much interest due to their potential to generate relatively high luminous flux from a relatively small emitting area. The high brightness of these light sources can facilitate more precise control of light distribution by optical systems and miniaturization. Furthermore, it may be desirable to have a high-brightness light source for general lighting applications that is tunable over a wide range of color spaces / CCTs with good color rendering. Typically, to achieve color tunability, a combination of several light sources with different starting color points (e.g., various light sources with different phosphors, different primary colors (e.g., RGB) from direct emitters, or a combination thereof) may be required. To create a high-brightness, color-tunable light source, these multiple light sources may need to be optically combined with good color mixing and without further increase in etendue. However, in the case of systems with direct RGB lasers, optical combination of multiple light sources often results in a relatively low CRI unless there are unrealistic primary laser wavelength requirements, e.g., due to the inherent narrow spectral width of the laser lines and / or practical limitations, e.g., to certain limited spectral regions. Furthermore, for systems with two or more phosphor converters, the etendue tends to increase significantly (such as by at least a factor of 2), 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 commonly available light sources rather than requiring specialized equipment.

[0004] It is therefore an aspect of the present invention to provide an alternative light-generating system, which preferably also at least partially obviates one or more of the above disadvantages. The present invention may aim to eliminate or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative. [Means for solving the problem]

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

[0006] The system of the present invention offers the advantage of providing a high CRI for a high-brightness light source, which further facilitates control of the correlated color temperature of the system light. In particular, in embodiments, the system may include a (single) phosphor converter element, a (single) blue laser, and a (single) red laser. The red laser, emitting in a practically usable wavelength range, is used to increase the CRI and provide a color point on the blackbody locus (BBL) for a low CCT. The system of the present invention may facilitate providing system light with a tunable CCT, such as tunability from 2700K to 6500K, with a small etendue while maintaining a high CRI, e.g., a CRI of at least 80 or higher.

[0007] In particular, the system light may comprise a blue first device light, a red second device light, and a green-yellow luminescent material light, which together may provide a high CRI. In particular, the red second device light may further contribute to a high R9 value (red rendering). Because the first optical element may provide a controllable, wavelength-dependent modification, in particular transmittance or in particular reflectance, in the blue wavelength range, the relative contribution of the blue first device light in the system light can 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 by modifying the relative contribution of the blue first device light, to direct toward a particular color point, such as a color point on a BBL. In certain embodiments, the light generation system of the present invention may comprise at least one blue laser, a phosphor conversion element that receives the laser pump light and provides white light with a high CCT (not necessarily on a BBL), optics for collecting and pre-collimating the phosphor-converted light with partially transmitted blue light, a spectral filtering element placed after the collimating optics that transmits green-yellow converted light and potentially partially suppresses the blue laser light depending on its orientation, a red laser added / combined with the main optical path of the phosphor-converted light source, and means for adjusting the transmittance of the phosphor-converted blue light, such as by changing the angle of said spectral filtering element relative to the main optical axis.

[0008] In certain embodiments, the present invention provides a light-generation system including a first light-generation device, a second light-generation device, a luminescent material, a first optical element, and a control system, wherein the first light-generation device is configured to generate blue first device light, the first light-generation device comprising one or more of a laser diode and a superluminescent diode, the second light-generation device is configured to generate red second device light, the second light-generation device comprising one or more of a laser diode and a superluminescent diode, the luminescent material is configured downstream of the first light-generation device, the luminescent material is configured to convert at least a portion of the first device light to luminescent material light having one or more wavelengths in a green to yellow wavelength range, and the first optical element is configured to control the first light-generation device and the second light-generation device. and (ii) the first optical element has a controllable wavelength-dependent reflectance in the blue wavelength range; the light-generation 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; the control system is configured to control the spectral power distribution of the system light by controlling the wavelength-dependent transmittance of the first optical element; and the control system is configured to control the correlated color temperature of the system light to a value selected from a range of 1800 to 6500 K, wherein the correlated color temperature of the system light is controllable over a CCT control range of at least 250 K within the range of 1800 to 6500 K.

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

[0010] In embodiments, the first light-generating device may be configured to generate blue first device light, i.e., first device light having a (centroid) wavelength in the blue wavelength range. The terms "blue light" or "blue emission" particularly relate to light having a wavelength in the range of approximately 440 to 495 nm (including some purple and cyan hues). Thus, in embodiments, the first light-generating device may be configured to generate first device light having a (centroid) wavelength in the range of (approximately) 440 to 495 nm. In further embodiments, at least 80%, such as at least 90%, of the spectral power of the first device light may fall within the range of 440 to 495 nm. In particular, the first light-generating device may comprise a first light source configured to provide the (blue) first device light.

[0011] In further embodiments, the second light-generating device may be configured to generate red second device light, i.e., second device light having a (centroid) wavelength in the red wavelength range. The terms "red light" or "red emission" particularly relate to light having a wavelength in the range of approximately 620 to 780 nm. Thus, in embodiments, the second light-generating device may be configured to generate second device light having a (centroid) wavelength in the range of (approximately) 620 to 780 nm. In further embodiments, at least 80%, such as at least 90%, of the spectral power of the second device light may fall within the range of 620 to 780 nm. In particular, the second light-generating device may comprise a second light source configured to provide the (blue) first device light.

[0012] The first light-generating device may in embodiments 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 embodiments 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" particularly refers to a device that emits light through a process of light amplification based on stimulated emission of electromagnetic radiation. In particular, in embodiments, the term "laser" may refer to a solid-state laser. In certain embodiments, the term "laser" or "laser source," or similar terms, may refer to a laser diode (or diode laser).

[0014] Therefore, in embodiments, the first light-generating device (or the second light-generating device), in particular the first light source (or the second light source), may comprise a laser light source. In embodiments, the term "laser" or "solid-state laser" refers to a laser such as a cerium-doped lithium strontium (or calcium) aluminum fluoride (Ce:LiSAF, Ce:LiCAF), a chromium-doped chrysoberyl (alexandrite) laser, a chromium-ZnSe (Cr:ZnSe) laser, a divalent samarium-doped calcium fluoride (Sm:CaF) laser, a Ce:YAG laser, an Er:YAG laser, an erbium-doped and erbium-ytterbium co-doped laser, a chromium-ZnSe (Cr:ZnSe) laser, a chromium-doped ...chrysoberyl (alexandrite) laser, a chromium-ZnSe (Cr:ZnSe) laser, a chromium-doped calcium fluoride (Sm:CaF) laser, a Ce:YAG laser, an Er:YAG laser, an erbium-doped and erbium-ytterbium co-doped laser, a chromium-ZnSe (Cr:ZnSe) laser, a chromium-doped calcium fluoride (Sm:CaF) laser, a chromium-ZnSe (Cr:ZnSe) laser, a chromium-doped calcium fluoride (Sm:CaF) laser, a chromium-doped calcium fluoride (Sm:CaF) laser, a chromium-doped calcium fluoride (Sm:CaF) laser, a chromium-doped calcium fluoride (Ce:YAG Glass lasers, F-center lasers, Holmium YAG (Ho:YAG) lasers, Nd:YAG lasers, NdCrYAG lasers, Neodymium-doped yttrium calcium oxoborate Nd:YCa4O(BO3)3 or Nd:YCOB, Neodymium-doped yttrium orthovanadate (Nd:YVO4) lasers, Neodymium-glass (Nd:glass) lasers, Neodymium-YLF (Nd:YLF) solid-state lasers, Promethium-147-doped phosphate glass (147Pm 3+:glass) solid-state laser, ruby laser (Al2O3:Cr 3+ ), thulium YAG (Tm:YAG) laser, titanium sapphire (Ti:sapphire; Al2O3:Ti 3+ ) lasers, trivalent uranium-doped calcium fluoride (U:CaF2) solid-state lasers, ytterbium-doped glass lasers (rod, plate / chip and fiber), ytterbium YAG (Yb:YAG) lasers, Yb2O3 (glass or ceramics) lasers, etc.

[0015] In embodiments, 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 salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc.

[0016] A laser may be combined with an upconverter to reach shorter (laser) wavelengths. For example, upconversion can be achieved with some (trivalent) rare earth ions or with nonlinear crystals. In another example, a laser, such as a dye laser, can be combined with a downconverter to reach longer (laser) wavelengths.

[0017] As can be derived from the following description, the term "laser light source" can also refer to a plurality of (different or identical) laser light sources. In certain embodiments, the term "laser light source" can refer to a plurality of N (identical) laser light sources. In embodiments, N=2 or more. In certain embodiments, N can be at least 5, in particular at least 8. In this way, higher brightness can be obtained. In embodiments, the laser light sources can be arranged in a laser bank (see also above). The laser bank can, in embodiments, include a heat sink and / or optics, for example a lens for collimating the laser light. In further embodiments, the first light-generating device can have a single light source. Similarly, in embodiments, the second light-generating device can have a single light source.

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

[0019] The laser source light, in embodiments, may have one or more bands, having a bandwidth as known for lasers. In particular embodiments, the bands may be relatively sharp lines, such as those having a full width half maximum (FWHM) in the range of less than 20 nm at room temperature (RT), such as 10 nm or less. Thus, the source light may have a spectral power distribution (intensity in energy scale as a function of wavelength) that may include one or more (narrow) bands. In particular, in embodiments, the first light-generating device may be configured to provide first device light having a FWHM of 20 nm or less, such as 10 nm or less, particularly at room temperature; i.e., in embodiments, the first device light may have a FWHM of 20 nm or less, such as 10 nm or less, particularly at room temperature. In further embodiments, the second light-generating device may be configured to provide the second device light having a FWHM of 20 nm or less, such as 10 nm or less, particularly at room temperature, i.e. in embodiments the second device light may have a FWHM of 20 nm or less, such as 10 nm or less, particularly at room temperature.

[0020] The (source light) beam may be a focused or collimated beam of (laser) source light. The term "focused" may in particular refer to converging to a small spot. This small spot may be at a discrete converter region or (slightly) upstream or (slightly) downstream of the discrete converter region. 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 (at the side) is not substantially larger than the cross-sectional shape (perpendicular to the optical axis) of the discrete converter region (at the location where the source light illuminates the discrete converter region). Focusing may be performed by one or more optical systems, such as (focusing) lenses. In particular, two lenses may be applied to focus the laser source light. Collimation may be performed by one or more (other) optical systems, such as collimating elements, such as lenses and / or parabolic mirrors. In embodiments, the beam of (laser) source light may in embodiments be relatively highly collimated, such as ≦2° (FWHM), more particularly ≦1° (FWHM), and most particularly ≦0.5° (FWHM). Thus, ≦2° (FWHM) may be considered as (highly) collimated source light. Optical systems may be used to provide the (highly) collimated light (see also above).

[0021] Superluminescent diodes are known in the art. Superluminescent diodes can be described as semiconductor devices that potentially have the brightness of laser diodes but the ability to emit broad-spectrum, low-coherence light like LEDs. US 2020192017, for example, indicates that "with current technology, a single SLED can emit light over a bandwidth of, for example, up to 50-70 nm in the 800-900 nm wavelength range with sufficient spectral flatness and sufficient output." In the visible range used for display applications, i.e., the 450-650 nm wavelength range, a single SLED can emit light over a bandwidth of up to 10-30 nm with current technology. These emission bandwidths are too small for display or projector applications requiring red (640 nm), green (520 nm), and blue (450 nm), i.e., RGB, emission. Furthermore, superluminescent diodes are described, inter alia, in Chapter 9.3, "Superluminescent Diodes," of "Edge Emitting Laser Diodes and Superluminescent Diodes," https: / / doi.org / 10.1002 / 9783527825264.ch9, first published August 3, 2020, by authors Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Najda, Thomas Slight, and Piotr Perlin, and edited by Fabrizio Roccaforte and Mike Leszczynski. This book, and particularly Chapter 9.3, is incorporated herein by reference. The book, inter alia, describes superluminescent diodes (SLDs) as emitters that combine the characteristics of laser diodes and light-emitting diodes. 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 may be specially designed to prevent the formation of standing waves and lasing. Nevertheless, the presence of the waveguide ensures the emission of a high-quality light beam with high spatial coherence, which is simultaneously characterized by low temporal coherence. Currently, the most successful designs of nitride SLDs are those with bent, curved, or tilted waveguide geometries and tilted facet geometries, while in all cases the front end of the waveguide meets the device facet at an angle, as shown in Figure 9.10. The tilted waveguide suppresses reflection of light from the facet into the waveguide by directing it outward into the lossy unpumped area of the device chip. Therefore, SLDs can be particularly useful as semiconductor light sources in which spontaneous emission is amplified by stimulated emission in the active region of the device. Such light emission is called "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 the semiconductor light source has the advantages that speckle is significantly reduced or invisible, and the spectral distribution of the emitted light is much broader than that of laser diodes, which may be more suitable for lighting applications. In particular, the spectral power distribution of the superluminescent diode can be changed by changing the current. In this way, the spectral power distribution can be controlled (see, for example, Abdullah A. Alatawi et al., Optics Express Vol. 26, Issue 20, pp. 26355-26364, https: / / doi.org / 10.1364 / OE.26.026355).

[0022] In embodiments, the light-generation system may comprise a luminescent material. In particular, the luminescent material may be configured downstream of the first light-generating device, in particular with respect 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 within the first device light path.

[0023] The luminescent material may be configured, inter alia, to convert at least a portion of the first device light to luminescent material light. In embodiments, the luminescent material light may have one or more wavelengths in the green-yellow wavelength range. The terms "green light" or "green emission" particularly relate to light having a wavelength in the range of approximately 495 to 570 nm. The terms "yellow light" or "yellow emission" particularly relate to light having a wavelength in the range of approximately 570 to 590 nm. Thus, the terms "green-yellow light" or "green-yellow emission" may particularly relate to light having a wavelength in the range of (approximately) 495 to 590 nm. Thus, in embodiments, the luminescent material may be configured to convert at least a portion of the first device light to luminescent material light having a (centroid) wavelength in the range of 495 to 590 nm. In further embodiments, at least 80%, such as at least 90%, of the spectral power of the luminescent material light may fall within the range of 495 to 590 nm.

[0024] The term "luminescent material" particularly refers to a material capable of converting first device light, in particular blue light, into luminescent material light. Generally, the first device light and the luminescent material light have different spectral power distributions. Therefore, instead of the term "luminescent material," the terms "luminescence converter" or "converter" may be used. Generally, the luminescent material light has a spectral power distribution at a wavelength greater than that of the first device light, which is the case of so-called downconversion. In embodiments, the "luminescent material" may particularly refer to a material capable of converting radiation, for example, into visible light. For example, in embodiments, the luminescent material may be capable of converting blue light into visible light. Therefore, the luminescent material may emit radiation when excited with blue light. Generally, the luminescent material is a downconverter, i.e., radiation with a shorter wavelength is converted into radiation with a longer wavelength (λ<λ).

[0025] In embodiments, the term "luminescence" may refer to phosphorescence. In embodiments, the term "luminescence" may refer to fluorescence. The term "emission" may be applied instead of the term "luminescence." Thus, 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 and / or fluorescent materials, in embodiments.

[0026] The term "luminescent material" can refer to multiple different luminescent materials. Examples of possible luminescent materials are provided below. Thus, the term "luminescent material" can, in certain embodiments, refer to a luminescent material composition.

[0027] For example, A3B5O 12Experiments were conducted with various luminescent materials from the group of A3B5O4, A3B5O5, A3B5O6, A3B5O7, A3B5O8, A3B5O9, A3B5O9, A3B5O9, A3B5O10, A3B5O11, A3B5O12, A3B5O13, A3B5O14, A3B5O15, A3B5O16, A3B5O17, A3B5O18, A3B5O19, A3B5O16, A3B5O19 ... 12 Tests were conducted with combinations of luminescent materials selected from the group including: A3B5O:Ce. It will be apparent to those skilled in the art that the centroid wavelength and phosphor selection may depend on the desired CCT, CRI, and R9. For CCT values in the range of 2700 to 4000K, A3B5O 12 Particularly good results (over the indicated centroid wavelengths of the first and second light-generating devices) have been obtained with luminescent materials selected from the group: A3B5O 12 :Ce group.

[0028] In embodiments, the luminescent material may be selected from garnets and nitrides, in particular doped with trivalent cerium or divalent europium, respectively. The term "nitride" may also refer to oxynitrides or nitridosilicates, etc. It should be noted that the term "luminescent material" may also refer to a combination of two or more different luminescent materials.

[0029] As noted above, in certain embodiments, the luminescent material is ABO 12:Ce-type luminescent materials, where A in embodiments 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 B in embodiments comprises one or more of Al, Ga, In and Sc. In particular, A may comprise one or more of Y, Gd and Lu, in particular one or more of Y and Lu. In particular, B may comprise at least Al, such as one or more of Al and Ga, more in particular essentially only Al. Thus, a particularly suitable luminescent material may be a cerium-comprising garnet material. Garnet embodiments are particularly those of A3B5O 12 The present invention includes a garnet, wherein A includes at least yttrium or lutetium, and B includes at least aluminum. Such garnets may be doped with cerium (Ce), praseodymium (Pr), or a combination of cerium and praseodymium, but may particularly be doped with Ce. In particular, B includes aluminum (Al), but B may also partially include gallium (Ga) and / or scandium (Sc) and / or indium (In), particularly up to about 20% of Al, more particularly up to about 10% of Al (i.e., B ions consist essentially of 90 mol % or more of Al and 10 mol % or less of one or more of Ga, Sc, and In). B may particularly include up to about 10% of gallium. In another variation, B and O may be at least partially replaced by Si and N. The element A may be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb), and lutetium (Lu). Furthermore, Gd and / or Tb may be present in an amount up to about 20% of A. In certain embodiments, the garnet luminescent material may be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb), and lutetium (Lu). 1-x Lu x )3B5O 12 :Ce, where x is greater than or equal to 0 and less than or equal to 1. The term ":Ce" indicates that some of the metal ions in the luminescent material (i.e., in garnets, some of the "A" ions) are replaced with Ce. For example, (Y 1-xLu 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 generally replaces A by 10% or less, and generally the Ce concentration is in the range of 0.1 to 4%, particularly 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the complete and detailed formula is (Y 0.1 Lu 0.89 Ce 0.01 )3Al5O 12 and can be. Ce in garnet is substantially in the trivalent state or only in the trivalent state, as is known to those skilled in the art.

[0030] In an embodiment, the luminescence material (therefore) contains A3B5O 12 and up to 10% of B - O can be replaced by Si - N.

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

[0032] In a further embodiment, the luminescence material is (Y x1 A' x2 Ce x3 )3(Al y1 B' y2 )5O 12 and may contain, where x1 + x2 + x3 = 1, x3>0, 0 <x2 + x3 ≤ 0.2, y1 + y2 = 1, 0 ≤ y2 ≤ 0.2, A' contains one or more elements selected from the group consisting of lanthanides, and B' contains 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, in particular, x1>0, such as at least 0.8, such as x1>0.2. Garnet with Y can provide an appropriate spectral power distribution.

[0033] In further embodiments, 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), and in certain embodiments, B-O may refer to Al-O. As noted above, in certain embodiments, x3 can be selected from the range of 0.001 to 0.04. In particular, such luminescent materials have an appropriate spectral distribution (see below), relatively high efficiency, relatively high thermal stability, and can enable a high CRI (in combination with the first source light and the second source light (and the optical filter)). Thus, in certain embodiments, A can be selected from the group consisting of Lu and Gd. Alternatively, or in addition, B can include Ga. Thus, in embodiments, the luminescent material is (Y x1 (Lu,Gd) x2 Ce x3 )3(Al y1 Ga y2 )5O 12 and Lu and / or Gd may be available. Even more particularly, x3 is selected from the range of 0.001 to 0.1, 0 < x2 + x3 ≤ 0.1, and 0 ≤ y2 ≤ 0.1. Further, in certain embodiments, up to 1% of B-O can be replaced by Si-N. Here, the percentage refers to moles (as is known in the art), and for example, see also EP3149108. In still other specific embodiments, the luminescent material is (Y x1 Ce x3 )3Al5O 12 and x1 + x3 = 1, 0 < x3 ≤ 0.2, and is 0.001 to 0.1, etc.

[0034] In certain embodiments, the light generating device may only include a luminescent material selected from the type of garnet containing cerium. In still other specific embodiments, the light generating device is (Y x1 A' x2 Ce x3 )3(Al y1 B'y2 )5O 12 includes a single type of luminescent material such as etc. Thus, in certain embodiments, the light generating device has a luminescent material, and at least 85% by weight, more particularly at least about 90% by weight, for example even more particularly at least about 95% by weight of the luminescent material is (Y x1 A' x2 Ce x3 )3(Al y1 B' y2 )5O 12 where A' includes one or more elements selected from the group consisting of lanthanides, B' includes one or more elements selected from the group consisting of Ga, In and Sc, x1 + x2 + x3 = 1, x3 > 0, 0 < x2 + x3 ≦ 0.2, y1 + y2 = 1, and 0 ≦ y2 ≦ 0.2. In particular, x3 is selected from the range of 0.001 to 0.1. Note that in embodiments, x2 = 0. Instead, or in addition, in embodiments, y2 = 0.

[0035] In certain embodiments, A may particularly include at least Y, and B may particularly include at least Al.

[0036] Instead, or in addition, the luminescent material may include a luminescent material of the A3Si6N 11 :Ce 3+ type, and A includes one or more of Y, La, Gd, Tb and Lu, such as one or more of La and Y in embodiments.

[0037] In embodiments, the luminescent material may instead, or in addition, be MS:Eu 2+ and / or M2Si5N8:Eu 2+ and / or MAlSiN3:Eu 2+ and / or Ca2AlSi3O2N5:Eu 2+and the like, where M comprises one or more of Ba, Sr, and Ca, and in particular embodiments, at least Sr. Thus, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is substantially or exclusively divalent, replacing one or more of the indicated divalent cations. Generally, Eu is not present in an amount greater than 10% of the cations, and the presence of Eu is particularly in the range of about 0.5 to 10%, more particularly in the range of about 0.5 to 5%, relative to the cation it replaces. The term ":Eu" indicates that a portion of the metal ions is Eu (in these examples, Eu 2+ For example, if we assume 2% Eu in CaAlSiN3:Eu, the correct formula is (Ca 0.98 EU 0.02 )AlSiN3. Divalent europium generally replaces divalent cations, such as the divalent alkaline earth cations mentioned above, particularly Ca, Sr, or Ba. The material (Ba,Sr,Ca)S:Eu may also be denoted MS:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca). In particular, M in this compound includes calcium or strontium, or calcium and strontium, more particularly calcium. Here, Eu is introduced to replace at least a portion of M (i.e., one or more of Ba, Sr, and Ca). Furthermore, the material (Ba,Sr,Ca)2Si5N8:Eu may also be denoted M2Si5N8:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca). In particular, M in this compound includes Sr and / or Ba. In a further particular embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), Ba 1.5 Sr 0.5Specifically, the material Si5N8:Eu (i.e., 75% Ba; 25% Sr) is composed of 50 to 100%, more particularly 50 to 90% Ba, and 50 to 0%, particularly 50 to 10% Sr. Here, Eu is introduced to replace at least a portion of M, i.e., one or more of Ba, Sr, and Ca. Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu may be denoted as MAlSiN3:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr), and calcium (Ca). In particular, M in this compound includes calcium or strontium, or calcium and strontium, more particularly calcium. Here, Eu is introduced to replace 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 above luminescent materials is substantially or exclusively in a divalent state.

[0038] In embodiments, the red luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is substantially or exclusively divalent, replacing one or more of the indicated divalent cations. Generally, Eu is not present in an amount greater than 10% of the cations, and the presence of Eu is particularly in the range of about 0.5 to 10%, more particularly in the range of about 0.5 to 5%, relative to the cations it replaces. The term ":Eu" indicates that a portion of the metal ions are Eu (in these examples, Eu 2+ For example, if we assume 2% Eu in CaAlSiN3:Eu, the correct formula is (Ca 0.98 EU 0.02 )AlSiN3. Divalent europium generally replaces a divalent cation, such as the divalent alkaline earth cations mentioned above, particularly Ca, Sr, or Ba.

[0039] The Eu in the above luminescent materials is substantially or exclusively in a divalent state, as known to those skilled in the art.

[0040] The blue luminescent material is YSO (Y2SiO5:Ce 3+ ), or similar compounds, or BAM (BaMgAl 10 O 17 :EU 2+ ), or a similar compound.

[0041] The term "luminescent material" as used herein relates in particular to inorganic luminescent materials. Instead of the term "luminescent material", the term "phosphor" may also be applied. These terms are known to those skilled in the art.

[0042] Alternatively or additionally, other luminescent materials may be applied, for example quantum dots and / or organic dyes, optionally embedded in a transparent matrix, for example a polymer such as PMMA or polysiloxane.

[0043] Quantum dots are small crystals of semiconductor materials, typically only a few nanometers wide or in diameter. When excited by incident light, quantum dots emit light whose color is determined by the size and material of the crystal. Therefore, by adjusting the size of the dot, light of a specific color can be generated. Most known quantum dots that emit in the visible range are based on cadmium selenide (CdSe) with shells such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium-free quantum dots, such as indium phosphide (InP), copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2), can also be used. Quantum dots exhibit very narrow emission bands, thus exhibiting saturated colors. Furthermore, the emission color can be easily tuned by adjusting the size of the quantum dot. Any type of quantum dot known in the art can be used in the present invention. However, for reasons of safety and environmental concerns, it may be preferable 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 be used, and "quantum confinement structure" in the context of this application is to be understood as, for example, quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nanowires.

[0045] Organic phosphors can also be used.

[0046] Different luminescent materials may have different spectral power distributions of their respective luminescent material light. Alternatively, or in addition, such different luminescent materials may have, among other things, different color points (or dominant wavelengths).

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

[0048] In embodiments, the luminescent material may be included in a luminescent body. In particular, the luminescent material is included in a luminescent body. The luminescent body may be a layer, such as a self-supporting layer. The luminescent body may also be a coating. The luminescent body may also have a luminescent coating on a support (in particular a light-transmitting support in the transmission mode or a reflective support in the reflection mode). In particular, the luminescent body may be essentially self-supporting. In embodiments, the luminescent material may be provided as a luminescent body, such as a luminescent single crystal, a luminescent glass or a luminescent ceramic body. Such a body may be denoted a "converter body" or a "luminescent body". In embodiments, the luminescent body may be a luminescent single crystal or a luminescent ceramic body. For example, in embodiments, a cerium-containing garnet luminescent material may be provided as a luminescent single crystal or as a luminescent ceramic body. In other embodiments, the luminescent body may comprise a light-transmitting body in which the luminescent material is embedded. For example, the luminescent body may comprise a glass body with a luminescent material embedded in the glass body. Alternatively, the glass may itself be luminescent. In other embodiments, the luminescent body may comprise a polymer body with a luminescent material embedded in the polymer body. In embodiments, the luminescent body may be a crystalline body, a ceramic body, or a luminescent material dispersed in another material, such as a polymer body (see further below). In further embodiments, at least one of the one or more luminescent bodies comprises a ceramic body. Furthermore, in embodiments, at least one of the one or more luminescent bodies comprises a luminescent material selected from the group consisting of (a) A3B5O 12: Ce-type luminescent materials, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and B comprises one or more of Al, Ga, In and Sc, and / or (b) A3Si6N 11 :Ce 3+ The system may comprise a luminescent material of the type A, where A comprises one or more of Y, La, Gd, Tb and Lu, in particular A comprises one or more of La and Y. Furthermore, in embodiments, the one or more luminescent bodies are a single luminescent body. Thus, the system may comprise a single luminescent body. The luminescent body is particularly configured to receive at least a portion of the first device light. Thus, in embodiments, the luminescent body is configured downstream of the first light-generating device. Furthermore, the luminescent body may be particularly configured to be in a light-receiving relationship with the first light-generating device.

[0049] In embodiments, the luminescent material may be operated in a transmissive mode, i.e. light supplied to the luminescent material may essentially enter the luminescent material at a first side and (optionally be converted) exit the luminescent material at a second side, in particular the first and second sides being arranged on opposite sides of the luminescent material. In further embodiments, the luminescent material may be operated in a reflective mode, i.e. light supplied to the luminescent material may enter the luminescent material at a first side and (optionally be converted) exit the luminescent material at the first side.

[0050] In some embodiments, the light-generation system may further comprise a first optical element. The first optical element may be configured, in particular, to be in a light-receiving relationship with the first light-generating device and the luminescent material, i.e., 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 wavelength-dependent modification of light provided to the first optical element. In particular, in some embodiments, the first optical element may have a controllable wavelength-dependent transmittance in the blue wavelength range. In further embodiments, the first optical element may have a controllable wavelength-dependent reflectance 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 control of the CCT of the system light by providing a means for controlling the proportion of blue first device light in the system light.

[0051] As will be explained further below, the CCT may further be influenced by (the output of) the second light-generating device, in particular under the control of the control system.

[0052] In further embodiments, the dichroic filter may be movable, e.g., tiltable or displaceable, relative to the optical axis of the (blue) first device light, and in particular the control system is configured to control the movement, e.g., control the position, of the dichroic filter. For example, in embodiments, the light-generating system may comprise an actuator configured to move, e.g., tilt or displace, the first optical element, and in particular the control system is configured to control the actuator. In further embodiments, the wavelength-dependent transmittance in the blue wavelength range may depend on a position, e.g., a tilt angle (α), or a displacement (d). Thus, the control system may be configured to control the position, and thereby the transmittance (or reflectance) of light in the blue wavelength range, and thereby the correlated color temperature of the system light.

[0053] In embodiments in which the first optical element comprises a dichroic filter, the transmittance in (at least part of) the blue wavelength range in the first position (p1) is at most 0.5 times the transmittance in (at least part of) the blue wavelength range in the second position (p2), i.e., by tilting or displacing the first optical element to the first position (p1) relative to the second position (p2), the transmittance of blue light can be reduced by a factor of 2. In further embodiments, the transmittance in (at least part of) the blue wavelength range in the first position (p1) 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, of the transmittance in (at least part of) the blue wavelength range in the second position (p2).

[0054] In embodiments in which the first optical element comprises a dichroic mirror, the reflectance in (at least part of) the blue wavelength range in the first position (p1) is at most 0.5 times the reflectance in (at least part of) the blue wavelength range in the second position (p2), i.e., by moving the first optical element to the first position (p1) relative to the second position (p2), the reflectance of blue light can be reduced by a factor of 2. In further embodiments, the reflectance in (at least part of) the blue wavelength range in the first position (p1) 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 reflectance in (at least part of) the blue wavelength range in the second position (p2).

[0055] In some embodiments, the first optical element may comprise a dichroic filter. In particular, in some embodiments, the dichroic filter may be tiltable relative to the optical axis of the (blue) first device light, and the control system may be configured to control the tilt angle (α). The tilt angle may refer to the angle between (i) a plane defined by the first optical element and (ii) the optical axis of the first device light (as the first device light reaches the first optical element). In further embodiments, the wavelength-dependent transmittance in the blue wavelength range may depend on the tilt angle (α). The control system may thus be configured to control the tilt angle (α), thereby controlling the transmittance (or reflectance) of light in the blue wavelength range and thereby the correlated color temperature of the system light. For this purpose, the control system may control the actuators described above.

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

[0057] In embodiments, 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 embodiments, the first optical element, in particular the dichroic mirror, may be arranged perpendicular to the optical axis and may be controllable with a deviation of up to about 45° relative to this optical axis. In embodiments, the 45° tilt may be a clockwise or counterclockwise tilt.

[0058] In embodiments in which the first optical element comprises a dichroic filter, the transmittance in the blue wavelength range, particularly in at least a portion of the blue wavelength range, or particularly in the entire blue wavelength range, at a first tilt angle (α1) is at most 0.5 times the transmittance in the blue wavelength range, such as in at least a portion of the blue wavelength range, at a second tilt angle (α2), i.e., by tilting the first optical element to the first tilt angle (α1) relative to the second tilt angle (α2), the transmittance of blue light can be reduced by a factor of 2. In further embodiments, the transmittance in the blue wavelength range at the first tilt angle (α1) 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, of the transmittance in (at least a portion of) the blue wavelength range at the second tilt angle (α2).

[0059] In embodiments in which the first optical element comprises a dichroic mirror, the reflectance in (at least part of) the blue wavelength range at a first tilt angle (α1) is at most 0.5 times the reflectance in (at least part of) the blue wavelength range at a second tilt angle (α2), i.e., by tilting the first optical element to the first tilt angle (α1) relative to the second tilt angle (α2), the reflectance of blue light can be reduced by a factor of 2. In further embodiments, the reflectance in (at least part of) the blue wavelength range at the first tilt angle (α1) is at most 0.75 times, particularly at most 0.3 times, particularly at most 0.4 times, such as at most 0.2 times, the reflectance in (at least part of) the blue wavelength range at the second tilt angle (α2). In embodiments, the at least part of the blue wavelength range may include the range from 440 to 480 nm, particularly the range from 440 to 495 nm, particularly the range from 445 to 475 nm.

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

[0061] In further embodiments, the dichroic filter may comprise one or more of a dichroic longpass filter and a dichroic narrow-band notch filter, in particular a dichroic longpass filter or in particular a dichroic narrow-band notch filter.

[0062] In an embodiment, the first optical element may be displaced (linearly) relative to, e.g., the optical axis of the first device light, and in particular the control system is configured to control the displacement (d). In a further embodiment, the wavelength-dependent transmittance in a blue wavelength range may depend on the displacement (d). Thus, the control system may be configured to control the displacement (d), and thereby control the transmittance (or reflectance) of light in a blue wavelength range, and thereby control the correlated color temperature of the system light.

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

[0064] As mentioned above, the control system may control the actuators described above, which may control the displacement.

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

[0066] As mentioned above, the light-generation 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, among others, generally, the system light may comprise (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 mentioned above, the light-generating system may further comprise a control system, which may be configured in particular 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, in particular in an operational mode (of the light-generating system), the spectral power distribution of the system light. 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 at least 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 transmittance or reflectance of the first optical element in the blue wavelength range.

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

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

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

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

[0073] In embodiments, the light-generation system may further comprise a second optical element, in particular the second optical element comprising a collimator element. The second optical element may in particular be arranged downstream of the luminescent material (and first light-generation device). In further embodiments, the second optical element may be arranged upstream of the first optical element. Thus, the second optical element may be arranged in a light-receiving relationship with the first light-generation device and the luminescent material, and may be arranged to provide collimated light, in particular collimated first device light and collimated luminescent material light, to the first optical element.

[0074] The light-generation system may further comprise (other) optical systems (see also above). The term "optical system" may in particular refer to (one or more) (third) optical elements. The optical system may include one or more of: mirrors, reflectors, collimators, lenses, prisms, diffusers, phase plates, polarizers, diffractive elements, diffraction gratings, dichroics, arrays of one or more of the foregoing, etc. Alternatively or additionally, the term "optical system" may refer to a holographic element or a mixing rod. In embodiments, the optical system may include one or more of: beam expander optics and zoom lens optics.

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

[0076] The term "light mixing chamber" may refer herein to an optical element, in particular a light guide, or in particular an optical chamber, configured to mix light from multiple light sources to provide an (essentially) uniform spectrum in the far field, said optical chamber may have light-reflecting walls.

[0077] As mentioned 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 operational mode (of the light-generating system).

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

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

[0080] The light-generating system may include a plurality of first light-generating devices, where two or more first light-generating devices are configured to generate first device light having different centroid wavelengths in the 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 light of the two or more first light-generating devices. Similarly, in such an embodiment, the light-mixing chamber may be configured to be in a light-receiving relationship with the two or more first light-generating devices, particularly the plurality of first light-generating devices.

[0081] Similarly, in embodiments, 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, particularly in an operational mode (of the light-generating system), by controlling the second light-generating device. For example, in embodiments, the control system is configured to control the luminous flux of the second device light by controlling the second light-generating device, such as by controlling the output 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 embodiments, the control system may adjust the second centroid wavelength (λ) of the second device light, such as by controlling the temperature of the second light-generating device. C2 ) to control the spectral power distribution of the system light.

[0083] In an embodiment, the luminescent material has a luminescent material optical centroid wavelength λ CL In particular, the luminescent material light may have a centroid wavelength λ CL may be selected from the range of 545 to 590 nm, such as the range of 520 to 590 nm, such as the range of 550 to 590 nm, in particular the range of 560 to 580 nm.

[0084] In a further embodiment, the first centroid wavelength λ C1 may be selected from the range of 440 to 500 nm, such as the range of 440 to 490 nm, in particular the range of 440 to 480 nm, such as the range of 450 to 480 nm. In further embodiments, the first centroid wavelength may be selected from the range of 440 to 470 nm, in particular the range of 445 to 465 nm. In further embodiments, the first centroid wavelength may be selected from the group comprising 445 nm, 450 nm, 455 nm, and 465 nm. In further embodiments, the first centroid wavelength may be 445 nm. In further embodiments, the first centroid wavelength may be 450 nm. In further embodiments, the first centroid wavelength may be 455 nm. In further embodiments, the first centroid wavelength may be 465 nm.

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

[0086] In particular, the first device light has a first centroid wavelength (λ ) selected from the range of 440 to 480 nm. C1), and the second device light has a second centroid wavelength (λ ) selected from the range of 620 to 650 nm. C2 ) and the luminescent material light has a luminescent material light centroid wavelength (λ ) selected from the range of 560 to 580 nm. CL ) may yield superior results.

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

[0088] Thus, the control system may 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, by controlling the relative contributions of the first device light, the second device light, and the luminescent material light in the system light, the control system may adjust the color point of the system light to (effectively) change the CCT of the system light while remaining on the BBL.

[0089] In embodiments, the first device light and the second device light may be combined upstream of the luminescent material. Thus, in embodiments, the luminescent material may be transmissive, in particular transparent, or in particular translucent, to the second device light. Notably, in embodiments, the luminescent material may be configured in 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 (red) second device light to the luminescent material (see below), the second light-generating device may comprise a superluminescent diode, whereby the (red) speckle may be eliminated.

[0091] In a further embodiment, the first device light and the second device light may be combined downstream of the luminescent material, i.e. the second device light may be combined with the first device light and the luminescent material.

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

[0093] In embodiments, the light generation system may further comprise one or more beam combiners, such as a beam combiner, in particular a plurality of beam combiners. The beam combiner may be configured, in particular, 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 embodiments, the beam combiner may be selected from the group of a surface scattering diffuser, a volume scattering diffuser, a holographic optical element, a light pipe, a light guide, a Köhler integrator optic, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, and a polarizing beam splitter, in particular, a holographic optical element, a light pipe, a Köhler integrator optic, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, and a polarizing beam splitter. In a further embodiment, the beam combiner may in particular comprise a fiber bundle combiner, in particular the fiber bundle combiner being configured to combine the first device light and the second device light.

[0094] In some embodiments, the beam combiner may be configured downstream of the first light-generating device (with respect to the first device optical path) and downstream of the second light-generating device (with respect to the second device optical path of the second device light). In further embodiments, the beam combiner may be configured upstream of the luminescent material. Alternatively, in further embodiments, the beam combiner may be configured downstream of the luminescent material. Similarly, in some embodiments, the beam combiner may be configured upstream of the first optical element, while in further embodiments, the beam combiner may be configured downstream of the first optical element.

[0095] The terms "upstream" and "downstream" refer to the positioning of an item or feature relative to the propagation of light from a light generating means (here, in particular the light source), such that relative to a first position in the light beam from the light generating means, a second position in the light beam that is closer to the light generating means is "upstream" and a third position in the light beam that is further away from the light generating means is "downstream".

[0096] The light-generating system may be part of or used in, for example, an office lighting system, a home application system, a shop lighting system, a domestic lighting system, an accent lighting system, a spot lighting system, a theatre lighting system, a fiber optic application system, a projection system, a self-lit display system, a pixelated display system, a segmented display system, a warning sign system, a medical lighting application system, an indicator sign system, a decorative lighting system, a portable system, an automotive application, an (outdoor) road lighting system, an urban lighting system, a greenhouse lighting system, horticultural lighting, digital projection, or an LCD backlight. The light-generating system (or the luminaire) may be part of or 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, particularly with a variable CCT.

[0098] The term "white light" and similar terms used herein are known to those skilled in the art. The white light may particularly refer to light having a correlated color temperature (CCT) between about 2000K and 20000K, particularly between about 1800K and 20000K, such as 2700K to 20000K, and for general illumination, particularly within the range of about 2000K to 7000K, such as 2700K to 6500K. In embodiments, for example, for backlighting applications or other applications, the correlated color temperature (CCT) may particularly be within the range of about 7000K to 20000K. In still other embodiments, the correlated color temperature (CCT) is particularly within about 15 SDCM (standard deviation of color matching) of the black body locus (BBL), particularly within about 10 SDCM of the BBL, and even more particularly within about 5 SDCM of the BBL.

[0099] In certain embodiments, the correlated color temperature (CCT) may be selected from the range of 6000 K to 12000 K, such as at least 8000 K, such as selected from the range of 7000 K to 12000 K. In still other embodiments, the correlated color temperature (CCT) may be selected from the range of 6000 K to 12000 K, such as selected from the range of 7000 K to 12000 K, particularly 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 approximately 380 to 780 nm. As used herein, UV may refer specifically to wavelengths selected from the range of 190 to 380 nm, such as 200 to 380 nm. As used herein, the terms "light" and "radiation" are used interchangeably unless the context clearly indicates 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 certain embodiments, particularly for lighting applications, the terms "light" and "radiation" refer to (at least) visible light.

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

[0102] The term "control" and similar terms refer, inter alia, to at least determining the behavior of an element or supervising the operation of an element. Thus, in this specification, the term "control" and similar terms may refer, for example, to imposing a behavior on the element (determining the behavior of an element or supervising the operation of an element), such as, for example, measuring, indicating, activating, opening, shifting, changing temperature, etc. The term "control" and similar terms may further include monitoring as well. Thus, the term "control" and similar terms may include imposing a behavior on an element, and may also include imposing a behavior on an element and monitoring the element. Control of the element may be performed by a control system, sometimes denoted a "controller." Thus, the control system and the element may be functionally coupled, at least temporarily or permanently. The element may comprise the control system. In embodiments, the control system and the element may not be physically coupled. Control can be performed via wired and / or wireless control. The term "control system" may also refer to a plurality of different control systems, particularly those that are functionally coupled, where, for example, one control system of the plurality of different control systems may be a master control system and one or more other control systems may be slave control systems. A control system may have a user interface or be functionally coupled to a user interface.

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

[0104] Thus, in embodiments, the control system may (also) be configured to be controlled by an app on a remote device. In such embodiments, the control system of the lighting system may be a slave control system or may be controlled in slave mode. For example, the lighting systems may be identifiable by a code, in particular a unique code for each lighting system. The control system of the lighting system may be configured to be controlled by an external control system that accesses the lighting system based on knowledge entered by a user interface comprising an optical sensor of the (unique) code (e.g. a QR code reader). The lighting system may also have means for communicating with other systems or devices, e.g. based on Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

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

[0106] However, in embodiments, a control system may be available that is adapted to provide at least said 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 may also be possible, such as performing the mode depending on a sensor signal or a (time) scheme. Said operating mode may also refer in embodiments to a system, apparatus, or device that can only operate in a single operating mode (i.e., "on", without further adjustability).

[0107] Thus, in embodiments, the control system may depend on one or more of a user interface input signal, a sensor signal (of a sensor), and a timer, where the term "timer" may refer to a clock and / or a predetermined timing scheme.

[0108] In yet another aspect, the present invention also provides a lamp or luminaire having a light-generating system as defined herein. The luminaire may further include a housing, optical elements, louvers, etc. The lamp or luminaire may further include a housing enclosing the light-generating system. The lamp or luminaire may have a light window or housing opening in the housing, and the system light may escape from the housing through the light window or housing opening. In yet another aspect, the present invention also provides a projection device having a light-generating system as defined herein. In particular, a projection device or "projector" or "image projector" may be an optical device that projects an image (or moving image) onto a surface, such as a projection screen. The projection device may include one or more light-generating systems as described herein. Accordingly, in one aspect, the present invention also provides a light-generating device selected from the group consisting of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, the light-generating device having a light-generating system as defined herein. The light-generating device may comprise a housing configured to accommodate or a carrier configured to support one or more elements of the light-generating system, for example, in embodiments the light-generating device may comprise a housing configured to accommodate or a carrier configured to 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 terms "illumination device" or "illumination system" and similar terms, the terms "light-generating device" or "light-generating system" (and similar terms) may be applied. An illumination device or illumination system may be configured to generate device light (or "illumination device light") or system light (or "illumination system light"). As above, the terms light and radiation may be used interchangeably.

[0110] The illumination system may comprise a light source, and the system light may, in embodiments, comprise one or more of source light and converted source light (such as luminescent material light).

[0111] The term UV radiation may, in certain embodiments, refer to near-UV radiation (NUV). Therefore, the term "(N)UV" may also be used herein to refer generally to UV and, in certain embodiments, to NUV. The term IR radiation may, in certain embodiments, refer to near-IR radiation (NIR). Therefore, the term "(N)IR" may also be used herein to refer generally to IR and, in certain embodiments, to NIR. As used herein, IR (infrared) may particularly refer to radiation having a wavelength selected from the range of 780 to 3000 nm, such as 780 to 2000 nm, for example, up to about 1500 nm, such as a wavelength of at least 900 nm, although other wavelengths may be possible in certain embodiments. Thus, the term IR may, as used herein, refer to one or more of near-infrared radiation (NIR (or IR-A)) and short-wavelength infrared radiation (SWIR (or IR-B)), particularly NIR.

[0112] The term "centroid wavelength," also denoted λc, is known in the art and refers to the wavelength value where half of the light energy is at shorter wavelengths and half of the light energy is at longer wavelengths, and the value is given in nanometers (nm). It is the wavelength that halves the integral of the spectral power distribution, as expressed by the formula λc = Σλ × I(λ) / (ΣI(λ)), where the sum 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 over the emission band normalized to the integrated intensity). The centroid wavelength may be determined, for example, under operating conditions. [Brief explanation 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 symbols indicate corresponding parts, and in which: [Figure 1A] 1 illustrates a schematic representation of an embodiment of a light-producing system. [Figure 1B] 1 illustrates a schematic representation of an embodiment of a light-producing system. [Figure 1C] 1 illustrates a schematic representation of an embodiment of a light-producing system. [Figure 2A] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 2B] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 2C] 10A and 10B schematically illustrate further aspects of embodiments of light-generating systems; [Figure 3A] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 3B] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 3C] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 3D] 10A and 10B illustrate schematic diagrams of further aspects of embodiments of light-generating systems; [Figure 4] 1 illustrates schematically an embodiment of a lighting device.

[0114] The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION OF THE INVENTION

[0115] 1A-1C schematically illustrate embodiments of a light-generation system of the present invention. In the illustrated embodiment, the light-generation system 1000 includes a first light-generation device 110, a second light-generation device 120, a luminescent material 200, and a first optical element 410. In the illustrated embodiment, the first light-generation device 110 is configured to generate blue first device light 111, and the second light-generation device 120 is configured to generate red second device light 121. Notably, both the first light-generation device 110 and the second light-generation 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 to luminescent material light 201 and is therefore configured downstream of the first light-generation device 110. The luminescent material light 201 may have one or more wavelengths in the green-to-yellow wavelength range. Thus, the light-generation system 1000 may be configured to generate a system light 1001 including one or more of a first device light 111, a second device light 121, and a luminescent material light 201, where the first device light 111 comprises blue light, the second device light 121 comprises red light, and the luminescent material light 201 comprises green-yellow light. The system light 1001 may thereby have an appropriate mix of colors for a high CRI, such as a CRI≧80. In the illustrated embodiment, a first optical element 410 is configured in a light-receiving relationship with the first light-generation device 110 and the luminescent material 200. In particular, the first optical element 410 may have a controllable wavelength-dependent transmittance and / or reflectance in the blue wavelength range. For example, in the illustrated embodiment, the first optical element 410 has a dichroic filter 415 that is movable, such as tiltable (Figures 1A-1B) or displaceable (Figure 1C), relative to the optical axis O of the first device light 111, and in particular, the wavelength-dependent transmittance in the blue wavelength range depends on the position p, such as the tilt angle α.As schematically illustrated in FIGS. 1A-1B , the tilt angle α may be, inter alia, the angle between (i) a plane defined by the first optical element 410 and (ii) the optical axis O of the first device light 111 (when the first device light 111 reaches the first optical element 410). Notably, in the illustrated embodiment, the light-generation system includes an actuator 430 configured to move the first optical element 410. In such an embodiment, the control system 300 may be, inter alia, configured to control the actuator 430. Thus, the amount of blue light in the system light can be adjusted via the first optical element 410, thereby adjusting the CCT of the system light. Notably, 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 (at least) the wavelength-dependent transmittance (or wavelength-dependent reflectance) of the first optical element 410, particularly in an operational mode (of the light-generation system 1000). In a further embodiment, the control system 300 may be configured, particularly in an operational mode (of the light generation system 1000), to control the correlated color temperature of the system light 1001 to a value selected from the range of 1800 to 6500 K, and particularly the correlated color temperature of the system light 1001 is controllable over a CCT control range of at least 250 K within the range of 1800 to 6500 K.

[0116] In the illustrated embodiment, the luminescent material is operated in a transmissive mode. In further embodiments, the luminescent material may be operated in a reflective mode.

[0117] In further embodiments, the dichroic filter 415 may comprise one or more of a dichroic long-pass filter, 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.

[0118] 1A schematically illustrates an embodiment in which the light-generation system 1000 further comprises a second optical element 420, which comprises a collimator element. Notably, in the illustrated embodiment, the second optical element 420 is arranged downstream of the luminescent material 200 and the first light-generation device 110, and upstream of the first optical element 410.

[0119] FIG. 1B schematically illustrates an embodiment in which the light-generation system 1000 further comprises a light-mixing chamber 450 configured downstream of the first light-generation device 110 and upstream of (at least a portion of) the luminescent material 200.

[0120] In the illustrated embodiment, the luminescent material 200 is configured downstream of the second light-generation device 120, and in particular in light-receiving relationship with the second light-generation device 120. Thus, in the illustrated embodiment, the luminescent material 200 may be transparent to the second device light 121. Notably, in the illustrated embodiment, the light-generation system 1000 further comprises a beam combiner 470, which is configured to combine the first device light 111 and the second device light 121. Notably, the beam combiner 470 may comprise a fiber bundle combiner 460 configured to combine the first device light 111 and the second device light 121. In a further embodiment, the beam combiner 470 may comprise a dichroic element configured to combine the first device light 111 and the second device light 121.

[0121] Specifically, in the illustrated 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 transmits and partially scatters the red laser light. The converted white light is collected and collimated by a second optical element 420, such as a compound parabolic concentrator (CPC), which may be attached to the luminescent material 200. In the illustrated embodiment, the (pre-collimated) beam passes through a dichroic long-pass filter, where a portion of the transmitted blue light may be filtered out depending on the angular orientation of the filter and the desired spectral composition. Finally, the resulting white beam may be further collimated, such as with a lens.

[0122] 1C schematically illustrates an embodiment in which the light-generation system 1000 includes multiple first light-generating devices 110, and the light-generation system 1000 further includes a beam combiner configured to combine the first device lights 111 of the multiple first light-generating devices 110. In such an embodiment, two or more first light-generating devices 110 may be configured to generate first device lights 111 with 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.

[0123] Thus, in an embodiment, the light generation system 1000 may have (a) a first beam combiner 470, 471 configured to combine first device light 111 of a plurality of first light generation devices, and (b) a second beam combiner 470, 472 configured to combine the first device light 111 and the second device light 121.

[0124] In further embodiments, the beam combiner 470, in particular the first beam combiner 470, 471, or in particular the second beam combiner 470, 472, may be selected from the group of a surface scattering diffuser, a volume scattering diffuser, a holographic optical element, a light pipe, a light guide, a Kohler integrator optic, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, and a polarizing beam splitter.

[0125] 1C further schematically illustrates a displacement d of the first optical element 410, by which the first optical element 410 can be moved between a first position p1 and a second position p2. Notably, in embodiments, the wavelength-dependent transmittance (or reflectance) in the blue wavelength range may differ between the first position p1 and the second position p2. For example, in embodiments, the first optical element 410 may comprise a patterned linear filter in which the optical density of transmitted blue light varies over the length of the filter, and a linear shift of the filter provides the tunability.

[0126] 2A schematically illustrates the spectrum of the first device light 111. FIG. 2A also schematically illustrates the wavelength-dependent transmittance of an embodiment of the first optical element 410, in terms of transmittance (in %) versus wavelength λ (in nm). In particular, in the illustrated embodiment, the transmittance depends on angles of incidence at the first optical element 410 of 0°, 10°, and 20°, i.e., tilt angles α of approximately 90°, 80°, and 70°. Thus, for certain embodiments, the first device light 111 may be largely transmitted at a 20° angle of incidence, such as a 30° angle of incidence, while the first device light 111 may be largely blocked at a 10° angle of incidence. However, even at an incident angle of 0°, the second device light 121 and the luminescent material light 201 may be essentially completely 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 through the first optical element regardless of the tilt angle α.

[0127] 2A schematically illustrates that varying the blue laser content in system light 1001 can be achieved using first optical element 410. Specifically, FIG. 2A shows that the transmittance of a dichroic long-pass filter can be modified depending on the angle of incidence of the incident light, with the filter's transmission edge shifting toward shorter wavelengths with increasing angle of incidence. By positioning the filter's edge at normal incidence close to the excitation laser wavelength and changing the angle of the filter relative to the optical axis of light propagation, it is theoretically possible to adjust the amount of blue light in the resulting spectrum from 0% to 95% of the initial intensity.

[0128] FIG. 2B shows the spectral power distribution of the system light 1001 in intensity I (in au) versus wavelength λ (in nm) at 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 luminescence material light centroid wavelength λ of the luminescence material light 201 CL In particular, in the illustrated embodiment, the first device light 111 has a first centroid wavelength λ 1 selected from the range of 440 to 480 nm. C1 and the second device light 121 has a second centroid wavelength λ selected from the range of 620 to 650 nm. C2 and the luminescent material light 201 has a luminescent material light centroid wavelength λ selected from the range of 520 to 590 nm, such as the range of 550 to 590 nm. CL have.

[0129] In particular, Figure 2B shows a schematic illustration of the results of a spectral simulation 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 from 2700 to 6500 K can be covered, and the intensity of the red laser is adjusted to achieve the desired color point on the BBL. The red laser wavelength of 638 nm was chosen due to the practical availability of relatively inexpensive high-power lasers (>5 W) for this wavelength range >637 nm. 465 nm for the blue was selected as the longest blue wavelength of commercially available laser diodes. A shorter blue wavelength may be more advantageous due to higher absorption by the YAG phosphor. However, a (relatively) longer blue wavelength may also have a positive effect on the CRI.

[0130] 2C schematically illustrates the spectral power distribution of system light 1001 provided by an embodiment of a light-generating system 1001 including at least two first light-generating devices 110, where the first optical element 410 includes a long-pass filter, specifically a long-pass filter with a controllable edge position, such as by controlling the angle α (see above). In particular, in the illustrated embodiment, one of the at least two first light-generating devices 110 is configured to provide first device light 111 with a center wavelength at about 455 nm for more efficient excitation of the luminescent material, while another of the at least two first light-generating devices 110 is configured to provide first device light 111 with a center wavelength at about 465 nm to contribute to improving the CRI. In this case, the application of the long-pass filter can be controlled to set the edge position above 460 nm to set the total amount of transmitted blue light for the initial color point. The color point tunability can be further affected by electronically adjusting the amount of laser power from the two separate blue laser channels. Thus, in the illustrated embodiment, one of the at least two first light-generating devices 110 may provide first device light 111 that is partially converted into luminescent material light 201, but the remainder of the first device light 111 is blocked by a long-pass filter, while the first device light 111 provided by another of the at least two first light-generating devices 110 may be essentially unconverted by the luminescent material 200 and largely pass through the long-pass filter. The amount of blue light in the system light 1001 can thereby be controlled by controlling another of the at least two first light-generating devices 110.

[0131] In a further embodiment, instead of a long-pass filter, a narrow-band notch filter can be used, such as one with a band suppression at or near 465 nm, in which case the suppression band and the variation in transmittance can also be controlled as a function of the angle of incidence.

[0132] Furthermore, color point tunability without mechanical adjustment can also be achieved using the effect of wavelength shift of the laser diode emission wavelength as a function of temperature. Typical values of wavelength shift are ∼1 nm / 10°C, with the emission shifting to longer wavelengths with increasing temperature. By having a filter with a sharp transition edge and adjusting the temperature of the laser diode (e.g., with a heating element), it is possible to adjust the amount of transmitted blue laser light through the dichroic filter over a wide range. Thus, 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, and the control system 300 may adjust the centroid wavelength λ of the first device light 111 by, among other things, controlling the temperature of the first light-generating device 110. C1 , and is configured to control the spectral power distribution of the system light 1001 by controlling

[0133] Similarly, pulse width modulation (PWM) may be used to shift the centroid wavelength, in particular while (essentially) maintaining the average luminous flux. Pulse width modulation can also effectively control the temperature of the light-generating device, in particular its junction temperature. Thus, in an embodiment, the control system 300 controls the pulse frequency of the first light-generating device 110 to shift the centroid wavelength λ of the first device light 111. C1 The optical fiber 1002 may be configured to control the spectral power distribution of the system light 1001 by controlling

[0134] 3A-3D schematically illustrate how the CRI and R9 values of the system light 1001 may vary depending on the (centroid) wavelength of the (blue) first device light 111 in an embodiment. The longest wavelength in the practical range investigated may be preferred to provide a high CRI over a wide CCT range. For example, at a centroid wavelength of about 465 nm, a CRI of 90 may be achieved for a CCT in the range of about 4000 K to about 5500 K.

[0135] In particular, FIG. 3A illustrates schematically the relative intensity I versus wavelength λ (in nm) for a blue light source with centroid wavelengths at 457, 460, 463, and 465 nm.

[0136] 3B schematically illustrates the CRI versus CCT (in K) for a blue light source with centroid wavelengths at 457, 460, 463, and 465 nm, or a combination of two blue light sources with centroid wavelengths at 457 and 465 nm. Thus, depending on the selected centroid wavelength of the first device light 111, a high CRI, such as about 80, particularly above 85, or even above 90, can be obtained over a wide CCT control range.

[0137] Thus, in an embodiment, the first device light has a first centroid wavelength λ of at least 463, such as at least 460, at least 457, in particular at least 465. C1 may have

[0138] In further embodiments, the CCT control range may comprise at least 500K, in particular at least 1500K, such as in the range of 1800 to 6500K, such as in the range of 2700 to 6500K, such as at least 1000K.

[0139] FIG. 3C shows a schematic diagram of intensity (in au) versus CCT (in K) for a blue light source with centroid wavelengths at 457, 460, 463, and 465 nm, or a combination of two blue light sources with centroid wavelengths at 457 and 465 nm.

[0140] FIG. 3D illustrates a schematic diagram of R9 versus CCT (in K) for a blue light source with centroid wavelengths at 457, 460, 463, and 465 nm, or a combination of two blue light sources with centroid wavelengths at 457 and 465 nm.

[0141] FIG. 4 schematically illustrates an embodiment of a lighting fixture 2 including a light-generating system 1000 as described above. Reference number 301 indicates a user interface that may be functionally coupled to a control system 300 included by or functionally coupled to the light-generating system 1000. FIG. 3 also schematically illustrates an embodiment of a lamp 1 including the light-generating system 1000. Reference number 3 indicates a projector device or projector system that may be used to project an image onto a wall or the like, which may also include the light-generating system 1000. Accordingly, FIG. 3 schematically illustrates an embodiment of an illumination device 1200 selected from the group of a lamp 1, a lighting fixture 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, and which includes the light-generating system 1000 as described herein. In an embodiment, such an illumination device may be a lamp 1, a lighting fixture 2, a projector device 3, a disinfection device, a photochemical reactor, or an optical wireless communication device. Illumination device light escaping illumination device 1200 is shown at 1201. Illumination device light 1201 may essentially consist of, and therefore in certain embodiments may be, system light 1001. Reference numeral 1300 refers to a space such as a room. Reference numeral 1305 refers to the floor, reference numeral 1310 refers to the ceiling, and reference numeral 1307 refers to the walls.

[0142] The term "plurality" refers to two or more.

[0143] The terms "substantially" or "essentially," and similar terms, used herein will be understood by those skilled in the art. The terms "substantially" or "essentially" can also include embodiments with "entirely," "completely," "all," etc. Thus, in embodiments, the adjectives substantially or essentially may be omitted. Where applicable, the terms "substantially" or "essentially" may also relate to 90% or more, including 100%, such as 95% or more, particularly 99% or more, and even more particularly 99.5% or more.

[0144] The term "comprises" also includes embodiments in which the term "comprises" means "consisting of."

[0145] The term "and / or" specifically refers to one or more of the items mentioned before and after "and / or." For example, the phrase "item 1 and / or item 2," and similar phrases, can refer to one or more of items 1 and 2. The term "comprising" can refer to "consisting of" in some embodiments, while in other embodiments it can refer to "including at least the specified species, and optionally one or more other species."

[0146] Furthermore, in the specification and claims, terms such as first, second, third, etc. are used to distinguish between like elements and not necessarily to describe a sequential or chronological order. The terms so used are interchangeable under appropriate circumstances, and it should be understood that the embodiments of the invention described herein are capable of operation in orders other than those described or illustrated herein.

[0147] The present specification may describe, among other things, devices, apparatus, or systems in operation. As will be apparent to those skilled in the art, the present invention is not limited to methods of operation or devices, apparatus, or systems in operation.

[0148] It should be noted that the above-described embodiments are illustrative of the invention rather than limiting, and that those skilled in the art will be able to design many other embodiments without departing from the scope of the appended claims.

[0149] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0150] The use of the verb "to have" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the specification and claims, words like "to have" and the like should be interpreted in their inclusive sense, i.e., "including, but not limited to," as opposed to their exclusive or exhaustive sense.

[0151] The singular reference of an element does not exclude the presence of a plurality of such elements.

[0152] The invention may be implemented by means of hardware comprising several distinct elements, or by means of a suitably programmed computer. In a device, apparatus or system claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain means are recited in mutually different dependent claims does not indicate that a combination of these means cannot be used to advantage. Thus, in yet another aspect, the invention provides software which, when run on a computer, is capable of implementing (one or more embodiments of) the method as described herein.

[0153] The present invention also provides a control system that may control a device, apparatus, or system or that may perform the methods or processes described herein. Still further, the present invention also provides a computer program product that, when executed on a computer operatively coupled to or included in a device, apparatus, or system, controls one or more controllable elements of such a device, apparatus, or system.

[0154] The invention further applies to a device, apparatus or system having one or more of the characterizing features described in the specification and / or shown in the accompanying drawings.The invention further relates to a method or process having one or more of the characterizing features described in the specification and / or shown in the accompanying drawings.

[0155] Various aspects described in this patent can be combined to provide additional advantages. Moreover, those skilled in the art will understand that embodiments can be combined, and that more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

1. 1. 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, the first light-generating device is configured to generate blue first device light, the first light-generating device comprising one or more of a laser diode and a superluminescent diode; the second light-generating device is configured to generate red second device light, the second light-generating device comprising one or more of a laser diode and a superluminescent diode; the luminescent material is configured downstream of the first light-generating device, the luminescent material configured to convert at least a portion of the first device light to luminescent material light having one or more wavelengths in a green to yellow wavelength range; the first optical element is configured to be in a light-receiving relationship with the first light-generating device and the luminescent material, and (i) the first optical element has a controllable wavelength-dependent transmittance in a blue wavelength range, and / or (ii) the first optical element has a controllable wavelength-dependent reflectance in a blue wavelength range; the light-generation 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; the control system is configured to control the spectral power distribution of the system light by controlling the first optical element, the control system is configured to control a correlated color temperature of the system light to a value selected from a range of 1800 to 6500 K, and the correlated color temperature of the system light is controllable over a CCT control range of at least 250 K within the range of 1800 to 6500 K; The light-generating system further comprises a plurality of first light-generating devices, wherein two or more first light-generating devices are configured to generate first device light having different centroid wavelengths in a blue wavelength range, and the control system is further configured to control the spectral power distribution of the system light by controlling the radiant flux of the device light of the two or more first light-generating devices.

2. 2. The light generation system of claim 1, wherein the first optical element comprises a dichroic filter, the dichroic filter being movable relative to the optical axis of the first device light, and the control system is configured to control the position of the dichroic filter, such that (i) the wavelength-dependent transmittance in a blue wavelength range depends on the position, or (ii) the wavelength-dependent reflectance in a blue wavelength range depends on the position.

3. 3. The light production system of claim 2, wherein the dichroic filter comprises one or more of a dichroic longpass filter, a dichroic narrowband notch filter, and a linear variable filter.

4. 4. The light generation system of claim 2, wherein the dichroic filter is tiltable relative to the optical axis, and the control system is configured to control a tilt angle of the dichroic filter, such that (i) the wavelength-dependent transmittance in a blue wavelength range depends on the tilt angle, or (ii) the wavelength-dependent reflectance in a blue wavelength range depends on the tilt angle.

5. 5. The light-generating system of claim 1, further comprising a second optical element, the second optical element comprising a collimator element, the second optical element being configured (a) downstream of the luminescent material and the first light-generating device, and (b) upstream of the first optical element, wherein the luminescent material is operated in a transmission mode.

6. 6. The light-generating system of claim 1, further comprising a light-mixing chamber arranged downstream of the first light-generating device and upstream of at least a portion of the luminescent material.

7. 7. The light-generating system of claim 1, wherein a first centroid wavelength of the first device light depends on a temperature of the first light-generating device, and the control system is configured to control the spectral power distribution of the system light by controlling the first centroid wavelength of the first device light.

8. 8. The light-generating system of claim 1, wherein the different centroid wavelengths in the blue wavelength range have a centroid wavelength selected from the range of 445 to 465 nm and a centroid wavelength selected from the range of 450 to 480 nm.

9. The luminescent material is ３ B ５ O １２ 9. The light-generating system of claim 1, comprising a luminescent material of the Ce type, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and B comprises one or more of Al, Ga, In and Sc.

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

11. 11. A light generation system according to any one of claims 1 to 10, wherein the luminescent material is transparent or semi-transparent to second device light, and the luminescent material is configured to be in a light receiving relationship with the second light generating device.

12. 12. The light-generation system of claim 11, further comprising a beam combiner configured to combine the first device light and the second device light, the beam combiner being selected from the group of a holographic optical element, a light pipe, a Kohler integrator optic, a collimator, a dichroic beam combiner, a dichroic cube, a dichroic beam splitter, a diffraction grating, a polarizing beam splitter, and a fiber bundle combiner.

13. 13. The light-generation system of claim 1, wherein the CCT control range includes a range of at least 500K within the range of 1800 to 6500K.

14. 14. The light generating system of claim 1, wherein the first device light has a first centroid wavelength selected from the range of 440 to 490 nm, the second device light has a second centroid wavelength selected from the range of 620 to 650 nm, and the luminescent material light has a luminescent material light centroid wavelength selected from the range of 560 to 580 nm.

15. 15. An illumination device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising a light generation system according to any one of claims 1 to 14.

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