Color control using high frequency wavelength swept sources and phosphors

Abstract

The present invention relates inter alia to a light generation system 1000 having a first light generation device 110, a second light generation device 120 and a luminescent material 200, wherein (A) the first light generation device 110 is configured to generate a first device light 111 and the second light generation device 120 is configured to generate a second device light 121, the first device light 111 and the second device light 121 having different spectral power distributions, (B) the luminescent material 200 is configured to convert at least a portion of one or more of the first device light 111 and the second device light 121 into luminescent material light 201, and (C) the first light generation device 110 is configured to convert at least two centroid wavelengths λ 1 having a wavelength difference of at least 10 nm with a variation frequency of at least 40 Hz in an operation mode of the light generation system 1000. 1c,1 , λ 1c,2 and (D) the light-generation system 1000 is configured to generate white system light 1001 comprising the luminescent material light 201, and the first device light 111 and the second device light 121 in the operating mode of the light-generation system 1000.

Description

[Technical field]

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

[0002] Devices including vertical cavity lasers are known in the art. For example, WO2004 / 107512 describes a white light laser integrated structure having a) a substrate and b) one or more individually addressable laser light pixels formed on the substrate to emit a white beam of laser light perpendicular to the substrate, each of the one or more individually addressable laser light pixels includes one or more organic light emitting diodes (OLEDs) and a plurality of organic vertical cavity lasers arranged to be optically pumped by the one or more OLEDs, the plurality of organic vertical cavity lasers emit light of different colors, and the one or more individually addressable laser light emitting pixels emit substantially white light when the different colors of light are combined. The plurality of organic vertical cavity lasers emit light of two different colors. Summary of the Invention [Problem to be solved by the invention]

[0003] A white LED light source, for example, has a light output of approximately 300 lm / mm 2 While static phosphor-converted laser white light sources can provide intensities up to about 20,000 lm / mm 2It can even give an intensity of up to 1000 nm. Ce-doped garnets (e.g., YAG, LuAG) may be the most suitable luminescence converters that can be used to pump with blue laser light, since the garnet host material has a very high chemical stability. Furthermore, at low Ce concentrations (e.g., less than 0.5%), temperature quenching may only occur above about 200° C. Furthermore, the emission from Ce has a very fast decay time, and therefore the occurrence of optical saturation can be essentially prevented. Assuming, for example, a reflection mode operation, blue laser light may be incident on the phosphor. This may achieve, in embodiments, a nearly complete conversion of blue light, resulting in the emission of converted light. It is for this reason that the use of garnet phosphors with relatively high stability and thermal conductivity is proposed. However, other phosphors may also be applied. Thermal management may still be a challenge when very high power densities are used.

[0004] High brightness light sources can be used in applications such as projection, stage lighting, spot lighting, automotive lighting, etc. For this purpose, laser-phosphor technology can be used, where a laser provides the laser light and for example a (remote) phosphor converts the laser light into converted light. The phosphor may in embodiments be arranged on or inserted into a heat sink for improved thermal management and thus higher brightness.

[0005] One of the problems that may be associated with such (laser) light sources is the thermal management of the (ceramic) phosphor. Another problem associated with such laser light sources may be the desire to create compact high power devices. Furthermore, it would be desirable to provide a light source that is wavelength tunable. However, in general, laser-based light sources are not wavelength tunable.

[0006] 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]

[0007] In an aspect, the present invention provides a light generation system ("system") comprising a first light-generating device, a second light-generating device, and a luminescent material. In particular, the first light-generating device may be configured to generate a first device light. Further, in particular, the second light-generating device may be configured to generate a second device light. Further, in particular, the first device light and the second device light (in an operation mode of the system) have different spectral power distributions. Further, in particular, the luminescent material may be configured to convert at least a portion of one or more of (a) the first device light and (b) the second device light into luminescent material light. In particular, the first light-generating device may comprise a tunable light generating device. The tunable light generating device may be configured to convert at least two centroid wavelengths (λ ) (of the first light) into luminescent material light in an operation mode of the light-generating system. 1c,1 , λ 1c,2 ) in a wavelength range of at least two centroid wavelengths. In particular, the two centroid wavelengths may have a wavelength difference of at least 10 nm, such as at least 20 nm. Furthermore, the tunable light generating device may be configured to generate a first device light that varies between at least two centroid wavelengths (λ ) with a variation frequency of at least 40 Hz, in particular at least 50 Hz, in an operation mode of the light generating system. 1c,1 , λ 1c,2) in the operation mode of the light generation system. Furthermore, the light generation system may be configured to generate a white system light including the luminescent material light and at least one of the first device light and the second device light in the operation mode of the light generation system. In particular, in an embodiment, the present invention relates to a light generation system having a first light generation device, a second light generation device, and a luminescent material, wherein (A) the first light generation device is configured to generate a first device light, and the second light generation device is configured to generate a second device light, the first device light and the second device light having different spectral power distributions, (B) the luminescent material is configured to convert at least a portion of one or more of the first device light and the second device light into luminescent material light, and (C) the first light generation device is configured to generate at least two centroid wavelengths (λ ) with a wavelength difference of at least 10 nm at a variation frequency of at least 40 Hz in the operation mode of the light generation system. 1c,1 , λ 1c,2 ), (D) the light-generation system is configured to generate white system light comprising the luminescent material light, and (at least one of) the first device light and the second device light in the operational mode of the light-generation system.

[0008] In such a system, it is possible to provide a relatively large color gamut and / or a relatively large CCT tunability with a limited number of light sources. Moreover, in such a system, it may be possible to provide white light with a controllable CCT (substantially along the blackbody locus). Moreover, a relatively high CRI may be provided with a limited number of light sources. Moreover, a relatively intense light may be provided with the system.

[0009] As mentioned above, the light generation system may in particular comprise a first light generating device, a second light generating device and a luminescent material.

[0010] In particular, the first light-generating device is configured to generate a first device light, and further in particular, the second light-generating device is configured to generate a second device light, and in particular, in an operation mode of the system, the first device light and the second device light have different spectral power distributions.

[0011] The first light-generating device may comprise one or more (first) light sources, more particularly one or more (first) solid-state light sources. Furthermore, the first light-generating device may comprise an optical system. Light escaping from the one or more light sources, i.e. first light source light (from the one or more first light sources), may in an embodiment be beam-shaped via the optical system. The first device light may in particular comprise the first light source light. More particularly, the first device light may consist of the (first light source) light of the one or more first light sources.

[0012] The second light-generating device may comprise one or more (second) light sources, more particularly one or more (second) solid-state light sources. Furthermore, the second light-generating device may comprise an optical system. Light escaping from the one or more light sources, i.e. second light source light (from the one or more second light sources), may in an embodiment be beam-shaped via the optical system. The second device light may in particular comprise the second light source light. More particularly, the second device light may consist of the (second light source) light of the one or more second light sources.

[0013] In the following, some general aspects regarding light sources that may be applied to (the light source of) the first light-generating device and (the light source of) the second light-generating device are described.

[0014] The term "light source" may in principle relate to any light source known in the art: it may be a conventional (tungsten) bulb, a low-pressure mercury lamp, a high-pressure mercury lamp, a fluorescent lamp, an LED (light-emitting diode).

[0015] In certain embodiments, the light source comprises a solid state LED light source (such as an LED or a laser diode (or "diode laser")).

[0016] The term "light source" may also relate to a plurality of light sources, such as 2 to 200 (solid-state) LED light sources. Thus, the term LED may also refer to a plurality of LEDs. Furthermore, the term "light source" may also refer in embodiments to so-called chip-on-board (COB) light sources. The term "COB" refers in particular to LED chips in the form of semiconductor chips that are not encapsulated or connected but are directly mounted on a substrate such as a PCB. Thus, several light-emitting semiconductor light sources may be arranged on the same substrate. In an embodiment, the COB is a multi-LED chip arranged together as a single lighting module.

[0017] The light source has a light escape surface. For conventional light sources like light bulbs or fluorescent lamps, the light escape surface can be the outer surface of a glass or quartz envelope. In the case of an LED, the light escape surface can for example be the LED die or the outer surface of a resin if the resin is applied to the LED die. In principle, the light escape surface can also be the end of a fiber. The term escape surface particularly relates to the part of the light source where the light actually leaves or escapes from the light source. The light source is arranged to provide a light beam. This light beam escapes from the light exit surface of the light source.

[0018] Similarly, the light-generating device may include a light escape surface, such as an end window.Further, similarly, the light-generating system may include a light escape surface, such as an end window.

[0019] The term "light source" may refer to a semiconductor light emitting device such as a light emitting diode (LED), a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSEL), an edge emitting laser, etc. The term "light source" may also refer to an organic light emitting diode (OLED), such as a passive matrix (PMOLED) or active matrix (AMOLED). In certain embodiments, the light source comprises a solid state light source (such as an LED or a laser diode). In embodiments, the light source comprises an LED (light emitting diode). The term "light source" or "solid state light source" may also refer to a superluminescent diode (SLED).

[0020] The term LED may also refer to multiple LEDs. Furthermore, the term "light source" may also refer in embodiments to so-called chip-on-board (COB) light sources. The term "COB" refers in particular to LED chips in the form of semiconductor chips that are not encapsulated or connected but are directly mounted on a substrate such as a PCB. Thus, multiple semiconductor light sources may be configured on the same substrate. In embodiments, a COB is a multi-LED chip configured together as a single lighting module.

[0021] The term "light source" may also refer to multiple (essentially identical (or different)) light sources, such as 2 to 2000 solid-state light sources. In embodiments, the light source may comprise one or more micro-optical elements (array of microlenses) downstream of a single solid-state light source, such as an LED, or downstream of multiple solid-state light sources (i.e. shared, for example, by multiple LEDs). In embodiments, the light source may comprise an LED with on-chip optics. In embodiments, the light source comprises a single pixelated LED (with or without optics) (in embodiments providing on-chip beam steering).

[0022] In an embodiment, the light source may be configured to provide a primary radiation to be used as such, for example a blue light source such as a blue LED, or a green light source such as a green LED, and a red light source such as a red LED. Such LEDs, which may not include a luminescent material ("phosphor"), may be denoted direct color LEDs.

[0023] However, in other embodiments, the light source may be configured to provide a primary radiation, a portion of which is converted into a secondary radiation. The secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be referred to as luminescent material radiation. The luminescent material may in embodiments be included by the light source, such as an LED with a luminescent material layer or dome that includes the luminescent material. Such an LED may be referred to as a phosphor converted LED or PC LED. In other embodiments, the luminescent material may be configured at some distance from the light source ("remote"), such as an LED with a luminescent material layer that is not in physical contact with the LED die. Thus, in certain embodiments, the light source may be a light source that, in operation, emits light at least at a wavelength selected from the range of 380 to 470 nm. However, other wavelengths may also be possible. This light may be partially used by the luminescent material.

[0024] In embodiments, the light-generating device may comprise a luminescent material. In embodiments, the light-generating device may comprise a PC LED. In other embodiments, the light-generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light-generating device may comprise a laser device, such as a laser diode. In embodiments, the light-generating device may comprise a superluminescent diode. Thus, in certain embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.

[0025] The light source may be configured to generate a source light having, among other things, an optical axis (O), a (beam shape), and a spectral power distribution. The source light may, in embodiments, have one or more bands having a bandwidth as known for lasers.

[0026] The term "light source" may therefore refer to a light generating element itself, e.g. a solid-state light source, or may refer to a package of one or more of said light generating elements, e.g. a solid-state light source, and an element containing a luminescent material, and (other) optics, e.g. a lens, a collimator. A light conversion element ("conversion element" or "converter") may have an element containing a luminescent material. A solid-state light source itself, e.g. a blue LED, is a light source. A combination of a solid-state light source (e.g. a light generating element) and a light conversion element optically coupled to said solid-state light source, e.g. a blue LED and a light conversion element, may also be a light source (but may also be referred to as a light generating device). A white LED is therefore a light source (but may also be referred to as a (white) light generating device).

[0027] The term "light source" as used herein may refer to light sources including solid state light sources such as LEDs or laser diodes or superluminescent diodes.

[0028] The term "light source" may therefore also refer in embodiments to a light source that is (also) based on conversion of light, such as a light source in combination with a luminescence conversion material. The term "light source" may therefore also refer to a combination of an LED and a luminescent material configured to convert at least a portion of the radiation of the LED, or a combination of a (diode) laser and a luminescent material configured to convert at least a portion of the radiation of the (diode) laser.

[0029] In embodiments, the term "light source" may refer to a combination of a light source, such as an LED, and an optical filter that may change the spectral power distribution of the light generated by the light source. In particular, the term "light-generating device" may be used to refer to a light source and further optical components, such as optical filters and / or beam shaping elements.

[0030] The phrases "different light sources" or "multiple different light sources" and similar phrases may, in embodiments, refer to multiple solid-state light sources selected from at least two different bins. Similarly, the phrases "same light source" or "multiple identical light sources" and similar phrases may, in embodiments, refer to multiple solid-state light sources selected from the same bin.

[0031] The terms "solid-state light source" or "solid-state material light source" and similar terms may refer, among other things, to semiconductor light sources such as light emitting diodes (LEDs), diode lasers, or superluminescent diodes.

[0032] The term "laser source" refers in particular to a laser. Such a laser may be configured to generate laser source light having one or more wavelengths in the UV, visible or infrared, in particular having a wavelength selected from the spectral wavelength range of 200 to 2000 nm, such as 300 to 1500 nm. The term "laser" refers in particular to a device that emits light through a process of light amplification based on stimulated emission of electromagnetic radiation.

[0033] 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, refer to a laser diode (or diode laser).

[0034] Thus, in an embodiment, the light source comprises a laser light source. In an embodiment, the term "laser" or "solid state laser" or "solid state material 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:CaF2) laser, an Er:YAG laser, an erbium doped and an erbium ytterbium cobalt fluoride (Er:YAG) ... doped glass lasers, F-center lasers, Holmium (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 (rods, plates / chips and fibers), ytterbium YAG (Yb:YAG) lasers, Yb2O3 (glass or ceramics) lasers, etc.

[0035] For example, including embodiments for second and third harmonic generation, the light source may be an F center laser, an yttrium orthovanadate (Nd:YVO4) laser, a promethium-147 doped phosphate glass (147Pm3+ :glass), and titanium sapphire (Ti:sapphire; Al2O3:Ti 3+ ) lasers. For example, taking into account second and third harmonic generation, such a light source can be used to generate blue light.

[0036] In embodiments, the terms "laser" or "solid state laser" or "solid state material 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, and the like.

[0037] 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.

[0038] As can be derived from the following, the term "laser source" can also refer to a plurality of (different or identical) laser sources. In certain embodiments, the term "laser source" can refer to a plurality of N (identical) laser sources. In embodiments, N=2 or more. In certain embodiments, N can be at least 5, such as in particular at least 8. In this way, higher brightness can be obtained. In embodiments, the laser sources can be arranged in a laser bank (see also above). The laser bank can in embodiments include a heat sink and / or an optics, e.g. a lens for collimating the laser light.

[0039] The laser source is configured to generate a laser source light (or "laser light"). The source light may consist essentially of the laser source light. The source light may also comprise the 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 a collimated source light. In yet other embodiments, the source light is in particular a (collimated) laser source light.

[0040] The laser source light may, in embodiments, have one or more bands, with a bandwidth as known for lasers. In certain embodiments, the bands may be relatively sharp lines, such as 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 has a spectral power distribution (intensity in energy scale as a function of wavelength) that may include one or more (narrow) bands.

[0041] 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 may be (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 essentially not larger than the cross-sectional shape (perpendicular to the optical axis) of the discrete converter region (where the source light illuminates the discrete converter region). Focusing may be performed with 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 with one or more (other) optical systems, such as collimation elements, such as lenses and / or parabolic mirrors. In embodiments, the beam of (laser) source light may be relatively highly collimated, such as ≦2° (FWHM), more particularly ≦1° (FWHM), 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).

[0042] The term "solid state laser" and similar terms may refer to solid state lasers such as those based on crystals or glasses doped with ions such as transition metal ions and / or lanthanide ions, fiber lasers, photonic crystal lasers, semiconductor lasers such as vertical cavity surface emitting lasers (VCSELs), and the like.

[0043] The term "solid-state light source" and similar terms may refer to semiconductor light sources, such as light emitting diodes (LEDs), diode lasers, or superluminescent diodes, among others.

[0044] Superluminescent diodes are known in the art and can be described as semiconductor devices that potentially can emit broad-spectrum, low-coherence light like an LED, while having the brightness of a laser diode.

[0045] US2020192017, 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 power." 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, for example, 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) emission, i.e., RGB. Furthermore, superluminescent diodes are described, inter alia, in chapter 9.3 superluminescent diodes in the book "Edge Emitting Laser Diodes and Superluminescent Diodes" https: / / doi.org / 10.1002 / 9783527825264.ch9, first published on August 3, 2020, by authors Szymon Stanczyk, Anna Kafar, Dario Schiavon, Stephen Najda, Thomas Slight, Piotr Perlin, and book editors Fabrizio Roccaforte, Mike Leszczynski. This book, in particular chapter 9.3, is incorporated herein by reference. In said book, inter alia, it is shown that superluminescent diodes (SLDs) are emitters that combine the characteristics of laser diodes and light-emitting diodes. SLD emitters use stimulated emission. This 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 designed in a special way 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 of light, which at the same time is characterized by low temporal coherence.Currently, the most successful designs of nitride SLDs are bent, curved or tilted waveguide geometries and tilted facet geometries, while in all cases the front end of the waveguide meets the device facet at an angle, as shown in Fig. 9.10. The tilted waveguide suppresses reflection of the light from the facet to the waveguide by directing it outwards into the lossy unpumped areas of the device chip. Thus, SLDs can be semiconductor light sources, in particular where spontaneous emission is amplified by stimulated emission in the active region of the device. Such 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 source has the advantage that speckle is greatly reduced or invisible, and the spectral distribution of the emission is much broader compared to laser diodes, which may make it more suitable for illumination applications. In particular, by varying the current, the spectral power distribution of the superluminescent diode can be varied, and in this manner the spectral power distribution can be controlled (see also, for example, Abdullah A. Alatawi et al., Optics Express Vol. 26, Issue 20, pp. 26355-26364, https: / / doi.org / 10.1364 / OE.26.026355).

[0046] Vertical-cavity surface-emitting lasers, or VCSELs, are known in the art and may be a type of semiconductor laser diode with a laser beam emitting vertically from the top surface, as opposed to edge-emitting semiconductor lasers (in-plane lasers), which emit from a surface formed by cutting individual chips from a wafer. As is known in the art, VCSELs may have tunable emission wavelengths. See, for example, Dupont et al., Applied Physics Letters 98(16):161105 - 161105-3, DOI:10.1063 / 1.3569591, Wendi Chang et al., Applied Physics Letters 105(7):073303, DOI:10.1063 / 1.4893758, Thor Ansbaek, IEEE Journal of Selected Topics in Quantum Electronics 19(4):1702306-1702306, DOI:10.1109 / JSTQE.2013.2257164, or CJ Chang-Hasnain, IEEE Journal of Selected Topics in Quantum Electronics ( Volume: 6, Issue: 6, Nov.-Dec. 2000), DOI:10.1109 / 2944.902146, all of which are incorporated herein by reference, describes tunable VCSELs, whose spectral power distribution can be varied, in particular by varying the voltage.

[0047] The light-generating device may comprise a plurality of different light sources, such as two or more subsets of light sources, each subset including one or more light sources configured to generate source light having essentially the same spectral power distribution, but with light sources of different subsets configured to generate source light having different spectral distributions. In such embodiments, the control system may be configured to control the plurality of light sources. In certain embodiments, the control system may control subsets of light sources individually (see further below).

[0048] Below, some embodiments relating to the luminescent material are described and then we return to some embodiments relating to the first light-generating device and the second light-generating device (respectively).

[0049] As noted above, the system may also include a luminescent material.

[0050] The term "luminescent material" refers in particular to a material capable of converting a first radiation, in particular one or more of UV and blue radiation, into a second radiation. Generally, the first and second radiation have different spectral power distributions. Therefore, instead of the term "luminescent material", the term "luminescence converter" or "converter" may also be applied. Generally, the second radiation has a spectral power distribution at a larger wavelength than the first radiation, which is the case of so-called down-conversion. However, in certain embodiments, the second radiation has a spectral power distribution with an intensity at a smaller wavelength than the first radiation, which is the case of so-called up-conversion.

[0051] In embodiments, the "luminescent material" may refer specifically to a material capable of converting radiation, for example to visible light and / or infrared light. For example, in embodiments, the luminescent material may be capable of converting one or more of UV radiation and blue radiation into visible light. The luminescent material may also convert radiation into infrared radiation (IR) in certain embodiments. Thus, when excited with radiation, the luminescent material emits radiation. In general, the luminescent material is a downconverter, i.e., a material capable of converting radiation of a smaller wavelength into radiation of a larger wavelength (λ ex <λ em ), in certain embodiments, the luminescent material may comprise an upconverter luminescent material, i.e., the larger wavelength radiation is converted to radiation having a smaller wavelength (λex >λ em ) is converted into radiation with a

[0052] In embodiments, the term "luminescence" may refer to phosphorescence. In embodiments, the term "luminescence" may refer to fluorescence. Instead of the term "luminescence", the term "emission" may be applied. Thus, the terms "first radiation" and "second radiation" may refer to excitation radiation and luminescence (radiation), respectively. Similarly, the term "luminescent material" may refer to phosphorescence and / or fluorescence, in embodiments.

[0053] The term "luminescent material" may refer to a number of different luminescent materials. Examples of possible luminescent materials are provided below. Thus, the term "luminescent material" may refer to a luminescent material composition in certain embodiments.

[0054] In an embodiment, the luminescent material is 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.

[0055] 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, particularly suitable luminescent materials are garnet materials containing cerium. Garnet embodiments are in particular of the type ABO 12The garnet includes A at least yttrium or lutetium and B at least aluminum. Such garnets may be doped with cerium (Ce), praseodymium (Pr) or a combination of cerium and praseodymium, but in particular with Ce. In particular, B includes aluminum (Al), but B may also partially include gallium (Ga) and / or scandium (Sc) and / or indium (In), in particular up to about 20% of Al, more in particular up to about 10% of Al (i.e., B ions essentially consist of 90 mol % or more of Al and 10 mol % or less of one or more of Ga, Sc and In). B may in particular include up to about 10% of gallium. In another variant, 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 are particularly present in an amount up to about 20% of A. In a particular embodiment, the garnet luminescent material is selected from the group consisting of (Y 1-x Lu x )3B5O 12 :Ce, where x is 0 or more and 1 or less. 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-x Lu x )3AlO 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 replaces A, generally up to 10%, and generally the Ce concentration is in the range of 0.1 to 4%, in particular 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the perfectly correct formula is (Y 0.1 Lu 0.89 Ce 0.01 )3AlO 12 The Ce in the garnet may be substantially or exclusively in the trivalent state, as known to those skilled in the art.

[0056] In an embodiment, the luminescence material is (therefore) A3B5O 12 and in certain embodiments, up to 10% of the B-O can be replaced by Si-N.

[0057] In certain embodiments, the luminescence material is (Y x1-x2-x3 A' x2 Ce x3 )3(Al y1-y2 B' y2 )5O 12 where x1 + x2 + x3 = 1, x3 > 0, 0 < x2 + x3 ≤ 0.2, y1 + y2 = 1, 0 ≤ y2 ≤ 0.2, A' includes one or more elements selected from the group consisting of lanthanides, and B' includes 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.

[0058] In certain embodiments, up to 10% of the 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 described above, in certain embodiments, x3 can be selected from the range of 0.001 to 0.04. In particular, such a luminescence material has an appropriate spectral distribution (see below), has a relatively high efficiency, has a relatively high thermal stability, and can enable a high CRI (in combination with the first light source light and the second light source light (and the optical filter)). Therefore, in certain embodiments, A can be selected from the group consisting of Lu and Gd. Alternatively, or in addition, B can include Ga. Therefore, in an embodiment, the luminescence material is (Y x1-x2-x3 (Lu,Gd) x2 Ce x3 )3(Al y1-y2 Ga y2 )5O12 It includes, 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), see, for example, EP3149108. In yet other specific embodiments, the luminescence material is (Y x1-x3 Ce x3 )3Al5O 12 It includes, x1 + x3 = 1, 0 < x3 ≤ 0.2, and is such as 0.001 to 0.1, etc.

[0059] In certain embodiments, the light generating device may only include a luminescence material selected from the garnet type containing cerium. In still other specific embodiments, the light generating device includes a single type of luminescence material such as (Y x1-x2-x3 A' x2 Ce x3 )3(Al y1-y2 B' y2 )5O 12 . Thus, in certain embodiments, the light generating device has a luminescence material, and at least 85% by weight, even more particularly at least about 90% by weight, for example even more particularly at least about 95% by weight of the luminescence material is (Y x1-x2-x3 A' x2 Ce x3 )3(Al y1-y2 B' y2 )5O 12 . Here, 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.

[0060] In certain embodiments, A may, inter alia, include at least Y, and B may, inter alia, include at least Al.

[0061] Alternatively, or in addition, the luminescent material may be A3Si6N 11 :Ce 3+ The present invention may include luminescent materials of the type A, where A includes one or more of Y, La, Gd, Tb, and Lu, such as one or more of La and Y in embodiments.

[0062] In an embodiment, the luminescent material may alternatively or additionally be 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 and replaces one or more of the divalent cations indicated. 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" refers to the fact that a portion of the metal ions are Eu (in these examples Eu 2+ For example, assuming 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, in particular 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 includes calcium or strontium, or calcium and strontium, more particularly calcium, in this compound, where 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 includes Sr and / or Ba in this compound. In a further particular embodiment, M consists of Sr and / or Ba (not taking into account the presence of Eu), Ba 1.5 Sr 0.5 In particular, it consists of 50-100%, more particularly 50-90% Ba and 50-0%, particularly 50-10% Sr, such as Si5N8:Eu (i.e. 75% Ba; 25% Sr), where 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 also 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 includes calcium or strontium, or calcium and strontium, more particularly calcium, in this compound. In particular, Eu is introduced to replace at least a portion of M (i.e. one or more of Ba, Sr and Ca). The Eu in the above luminescent materials is substantially or exclusively in a divalent state, as known to those skilled in the art.

[0063] In embodiments, the red luminescent material may include one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu, and (Ba,Sr,Ca)2Si5N8:Eu. In these compounds, europium (Eu) is substantially or exclusively divalent and replaces one or more of the divalent cations shown. 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, assuming 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.

[0064] The material (Ba,Sr,Ca)S:Eu is sometimes denoted as MS:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca), and in particular M comprises calcium or strontium, or calcium and strontium, more particularly calcium, in this compound, where Eu is introduced to replace at least a portion of M (i.e. one or more of Ba, Sr and Ca).

[0065] Furthermore, the material (Ba,Sr,Ca)2Si5N8:Eu may also be denoted as M2Si5N8:Eu, where M is one or more elements selected from the group consisting of barium (Ba), strontium (Sr) and calcium (Ca), and in particular, M in this compound comprises Sr and / or Ba. In further particular embodiments, M consists of Sr and / or Ba (not taking into account the presence of Eu), and Ba 1.5 Sr 0.5Particularly consisting of 50-100%, more particularly 50-90% Ba, and 50-0%, particularly 50-10% Sr, such as Si5N8:Eu (i.e., 75% Ba; 25% Sr), where Eu is introduced to replace at least a portion of M (i.e., one or more of Ba, Sr and Ca).

[0066] Similarly, the material (Ba,Sr,Ca)AlSiN3:Eu may also 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), and in particular M comprises calcium or strontium, or calcium and strontium, more particularly calcium, in this compound, where Eu is introduced to replace at least a portion of M (i.e. one or more of Ba, Sr and Ca).

[0067] The Eu in the above luminescent materials is substantially or exclusively in a divalent state, as known to those skilled in the art.

[0068] The blue luminescent material is YSO (Y2SiO5:Ce 3+ ), or a similar compound, or BAM (BaMgAl 10 O 17 :EU 2+ ), or a similar compound.

[0069] The term "luminescent material" as used herein relates specifically to inorganic luminescent materials.

[0070] Instead of the term "luminescent material", the term "phosphor" is sometimes applied, these terms being known to those skilled in the art.

[0071] 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.

[0072] Quantum dots are small crystals of semiconductor materials, generally with a width or diameter of only a few nanometers. When excited by incident light, quantum dots emit light with a color determined by the size and material of the crystal. Thus, by adapting the size of the dots, 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) and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used. Quantum dots exhibit very narrow emission bands, therefore they exhibit saturated colors. Moreover, the emission color can be easily tuned by adapting the size of the quantum dots. In the present invention, any type of quantum dot known in the art can be used. However, for reasons of environmental safety and concerns, it may be preferable to use cadmium-free quantum dots, or at least quantum dots that have a very low cadmium content.

[0073] Instead of or in addition to quantum dots, other quantum confinement structures may be used, where "quantum confinement structure" is to be understood in the context of this application as, for example, quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nanowires.

[0074] Organic phosphors can also be used. Examples of suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, such as the compounds sold by BASF under the name Lumogen®. Examples of suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170.

[0075] 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).

[0076] As mentioned above, other luminescent materials may be possible. Thus, in certain embodiments, the luminescent material is selected from the group of divalent europium-containing nitrides, divalent europium-containing oxynitrides, divalent europium-containing silicates, cerium-containing garnets, and quantum structures. The quantum structures may include, for example, quantum dots or quantum rods (or other quantum-type particles) (see above). The quantum structures may also include quantum wells. The quantum structures may also include photonic crystals.

[0077] As also indicated above, a solid-state material laser may include a luminescent material, such as a single crystal or glass containing the luminescent material, used to generate laser light. Some examples of such lasers are given above when talking about solid-state light sources, more particularly laser light sources. One or more of the above embodiments relating to luminescent materials may also be applied to such solid-state material lasers. However, the luminescent material described herein as one of at least three elements of the system may be configured in particular to convert at least a portion of one or more of the first device light and the second device light into luminescent material light. Thus, such a luminescent material may convert laser light and may not necessarily be configured to also generate laser light. Thus, the luminescent material light may not necessarily be laser light, but laser light is not excluded herein. However, in particular, the luminescent material light generated by the luminescent material is not laser light. More particularly, the luminescent material may be selected to obtain an emission band with a full width at half maximum (of the luminescent material light) of at least 40 nm, such as at least 50 nm. For example, the luminescent material may be selected to obtain an emission band with a full width at half maximum of at least 60 nm. This may be the case, for example, for trivalent cerium containing garnet luminescent materials (as described herein). Thus, in particular, the luminescent material may include a broadband emitter. The luminescent material may also have a plurality of broadband emitters. In particular, when two or more luminescent materials are applied to convert at least a portion of the first device light and / or at least a portion of the second device light, at least two of the two or more luminescent materials may be configured to provide a respective luminescent material light having an emission band with a full width at half maximum (of the luminescent material light) of at least 40 nm, such as at least 50 nm.

[0078] In particular, the luminescent material light may include visible light. The terms "visible", "visible light" or "visible emission" and similar terms refer to light having one or more wavelengths in the range of about 380 to 780 nm. In this specification, the terms "light" and "radiation" are used interchangeably unless the context makes clear 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.

[0079] In particular, the first light-generating device may comprise a wavelength-tunable light-generating device. In certain embodiments, the first light-generating device may comprise a (luminescent) colour-tunable light-generating device.

[0080] For example, in an embodiment, the first light-generating device comprises one or more of a vertical cavity surface-emitting laser (VCSEL) and a superluminescent diode.

[0081] Thus, in particular, the first light-generating device may provide first device light having at least two different spectral power distributions at different times, thus, in particular, the first light-generating device is operated in a pulsed mode.

[0082] In an embodiment of an operating mode of the system, the change between the at least two different spectral power distributions may be faster than the human eye can perceive, and thus the change between the at least two different spectral power distributions may be within 0.025 seconds, such as within 0.02 seconds, or even within about 0.0167 seconds.

[0083] The first light-generating device, in an embodiment, has (at least) two spectral power distributions, a first centroid wavelength λ 1c,1 and the second centroid wavelength λ 1c,2In some cases, the algorithm may sweep between those with

[0084] The spectral power distribution can be characterized by a centroid wavelength. The term "centroid wavelength", also denoted λc, is known in the art and refers to the wavelength value at which half of the light energy is at the shorter wavelength and half of the light energy is at the longer wavelength, the value being 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, at operating conditions.

[0085] In particular, the first light-generating device therefore has at least two centroid wavelengths (λ 1c,1 , λ 1c,2 ) in the operating mode. Thus, in effect, the first light generating device (or more precisely its device light) can be swept between two centroid wavelengths. When varying from the first and second centroid wavelengths, there may be intermediate centroid wavelengths. Thus, the term "tunable light generating device" refers to a device having a "tunable wavelength of at least two centroid wavelengths (λ)" and a "tunable light generating device configured to generate a first device light that can be swept between two centroid wavelengths (λ). 1c,1 , λ 1c,2 The term "at least two centroid wavelengths (λ)" is used. 1c,1 , λ 1c,2 In the embodiment, the first centroid wavelength and the second centroid wavelength (λ 1c,1 , λ 1c,2 ) may have a difference of at least 10 nm, such as at least 20 nm, at least 30 nm, or in further embodiments at least 40 nm (such as even at least 60 nm, or even at least 80 nm, in certain embodiments at least 100 nm). In certain embodiments, the at least two centroid wavelengths (λ 1c,1 , λ1c,2 ) may be at least 50 nm. Furthermore, the change from the first to the second centroid wavelength may be at a frequency of at least 40 Hz, such as at least 50 Hz, or more particularly at least 60 Hz, such as at least 80 Hz (and in certain embodiments (even) at least 100 Hz). Thus, in an embodiment, the first light-generating device is adapted to change at least two centroid wavelengths (λ ) with a wavelength difference of at least 10 nm, with a change frequency of at least 40 Hz, such as at least 60 Hz, or more particularly at least 80 Hz (and in certain embodiments (even) at least 100 Hz) in an operation mode of the light-generating system. 1c,1 , λ 1c,2 ) a tunable light generating device configured to generate a first device light varying between a wavelength of 100 .mu.m and a wavelength of 100 .mu.m. In particular, the varying frequency may be at least 60 Hz.

[0086] The luminescent material may be configured to convert at least a portion of the first device light and / or at least a portion of the second device light. Thus, the luminescent material may be configured downstream of the first light-generating device and / or the second light-generating device. The terms "upstream" and "downstream" refer to the location of an item or feature relative to the propagation of light from a light-generating means (here, in particular the light source), such that with respect to a first position in the light beam from the light-generating means, a second position in the light beam closer to the light-generating means is "upstream" and a third position in the light beam further away from the light-generating means is "downstream". In particular, the luminescent material may be configured to convert at least a portion of the first device light or at least a portion of the second device light.

[0087] The luminescent material may therefore be configured to convert at least a portion of the first device light. In particular, therefore, the operating conditions of the luminescent material and the first light-generating device are selected such that, in the operating mode, the luminescent material converts the first device light having the first centroid wavelength and the first device light having the second centroid wavelength. However, as mentioned above, the luminescent material may also be configured to convert at least a portion of the second device light. In an operating mode of the light-generating system, the second light-generating device converts at least two centroid wavelengths (λ 2 ) with a wavelength difference of at least 10 nm with a variation frequency of at least 40 Hz. 2c,1 , λ 2c,2 ), see also below, and where the luminescent material is configured to convert at least a portion of the second device light, the luminescent material and the second light generating device may be selected such that, in the operating mode, the luminescent material converts the second device light having the first centroid wavelength (of the second device light) and the second device light having the second centroid wavelength (of the second device light).

[0088] The system may be configured to generate white light in an operational mode. The white light may in particular comprise the luminescent material light and one or more of (a) the first device light and (b) the second device light. Even more particularly, the white light may in particular comprise the luminescent material light, the first device light and the second device light. Furthermore, in certain embodiments, the white light may essentially consist of the luminescent material light, the first device light and the second device light. Thus, in an embodiment, the light-generating system may be configured to generate white system light comprising the luminescent material light and at least one of the first device light and the second device light in the operational mode of the light-generating system.

[0089] The term "white light" in this specification is known to those skilled in the art. Said white light particularly relates to light having a correlated color temperature (CCT) between about 2000K and 20000K, particularly between 2700K and 20000K, particularly between about 1800K and 20000K, such as between about 2700K and 6500K for general illumination. In an embodiment, for backlight applications, the correlated color temperature (CCT) may particularly be within about 7000K and 20000K. In yet another embodiment, the correlated color temperature (CCT) is particularly within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), particularly within about 10 SDCM from the BBL, and even more particularly within about 5 SDCM from the BBL.

[0090] In the present invention, it may be possible to provide white light with a controllable CCT substantially along the blackbody locus, such as within 15 SDCM of the BBL, more particularly within 10 SDCM, and even more particularly within about 5 SDCM. More particularly, the CCT tunability may range from at least 500 K, more particularly at least 1000 K, such as at least 1500 K, even more particularly at least 2000 K. For example, the system light may be tunable between about 4500-6500 K (2000 K tunability), or between about 2200-4200 K (also 2000 K tunability), or in embodiments, for example, tunable over 2200-6500 K (4300 K tunability), although other ranges may be possible.

[0091] It is noted that in further embodiments, the system may have further modes of operation and the system light may comprise one or more of the luminescent material light, the first device light and the second device light. Furthermore, in certain embodiments, further light generating devices configured to generate device light having a different spectral power distribution than the first and second device lights may be available and contribute their light to the system light (in the modes of operation).

[0092] In particular, the first device light and the second device light may have different spectral power distributions. Whatever the centroid wavelength of the first device light, the first device light may be (substantially) different from the second device light. For example, the centroid wavelength of the first device light and the centroid wavelength of the second device light may differ by at least 30 nm, such as at least 80 nm, such as at least 50 nm. Furthermore, in further specific embodiments, the centroid wavelength of the first device light and the centroid wavelength of the second device light may differ by at least 60 nm, such as at least 105 nm, or even at least about 115 nm, such as at least 90 nm. Furthermore, in embodiments, the spectral overlap of a smaller emission band by a larger emission band may be less than 20%, such as less than 10% of the smaller emission band.

[0093] In certain embodiments, the first light-generating device and the second light-generating device may not be essentially controllable to such an extent that overlapping spectral power distributions of the first device light and the second device light are obtained. In particular, the spectral overlap of a smaller emission band with a larger emission band may be less than 1%, such as less than 0.5%.

[0094] As mentioned above, the first light generating device may comprise one or more light sources, in particular solid-state light sources. Furthermore, the first device light may be controllable. This may mean that the source light of the one or more light sources is controllable. For example, the one or more light sources of the first device may comprise one or more of the above-mentioned vertical cavity surface emitting lasers (VCSELs) and superluminescent diodes.

[0095] As mentioned above, in embodiments, the first device light may consist of the source light of the one or more light sources. However, other embodiments may be possible. For example, it may be possible that the source light is not in the visible range, while the first device light may be in the visible range. Alternatively, in embodiments, the source light may be in the red and the first device light may be in the blue. In particular, this may be achieved when using an upconverter material. Thus, in a particular embodiment, the first light-generating device (a) is adapted to generate at least two centroid wavelengths (λ 2 ) with a wavelength difference of at least 20 nm, at a variation frequency of at least 40 Hz, in particular at least 50 Hz, in an operating mode of the light-generating system. pc,1 , λ pc,2 ) (primary centroid wavelengths); and (b) a tunable first light source configured downstream of the tunable first light source and configured to generate a first light source light that varies between the at least two centroid wavelengths (λ pc,1 , λ pc,2 At least a portion of the first light source light that changes between the at least two center wavelengths (λ 1c,1 , λ 1c,2 and an upconverter material configured to convert the first device light into a frequency-doubling material. In particular, the upconverter material comprises one or more of an upconverter luminescence material and a frequency doubling material.

[0096] The up-conversion may be based, for example, on an up-converter luminescent material and a frequency-doubling conversion material, both of which are referred to herein by the collective term "conversion material". The up-conversion may be performed with a frequency-doubling material, such as a second harmonic generating crystal, for example, BiBO (BiBO), lithium iodate LiO, BBO (β-BaBO), KHPO, etc., or with a frequency-doubling material, such as, for example, Yb 3+ -Er 3+These may be based on luminescent materials, such as those based on coupling (e.g. systems based on "addition of photons by energy transfer" (APTE), now commonly known as energy transfer upconversion (ETU)), or may be based on, for example, Er 3+ This may be done via a two-step absorption process, as may be possible in Yb-based systems, or 3+ -Tb 3+ This may be achieved through cooperative sensitization processes, such as may be possible with binding, or through cooperative luminescence processes, or for example, by combining several Eu 2+ Frequency doubling (or wavelength halving) may be achieved via a two-photon excitation process, as is possible in Yb-based systems. 3+ -Tm 3+ may also be possible.

[0097] Another system is a Pr 3+ and / or Ho 3+ , Tb 3+ , Tm 3+ , Er 3+ It may be based on one or more of the following:

[0098] For example, in embodiments, the material (sometimes referred to as the "host material") may be selected from the group consisting of NaLnF4, LiLnF4, KLnF4, LnF3, BaLn2F8, SrLn2F8, CaLn2F8, and MgLn2F8, where Ln is (a) Pr 3+ , Yb 3+ , Ho 3+ , Tm 3+ and Er 3+ and more particularly, one or more of Ln 3+ is Gd 3+, and (b) Pr 3+ , Yb 3+ , Ho 3+ , Tm 3+ and Er 3+ and the material in particular has at least a first lanthanide ion and a second lanthanide ion different from the first lanthanide ion. For example, in an embodiment, the material may be selected from the group consisting of NaLnF4, LiLnF4, KLnF4, LnF3, LiYF4, KYF4, BaLn2F8, SrLn2F8, CaLn2F8, or MgLn2F8, where Ln is selected from the group consisting of: (a) Gd 3+ ,Pr 3+ , Tm 3+ Or Er 3+ and (b) one or more first lanthanide ions selected from the group consisting of Pr 3+ , Yb 3+ , Ho 3+ , Tm 3+ and Er 3+ and one or more second lanthanide ions selected from the group consisting of: wherein the material comprises at least a first lanthanide ion and a second lanthanide ion different from the first lanthanide ion. In particular embodiments, Ln may include one or more of Lu and La, as well as at least one or more first lanthanide ions and one or more second lanthanide ions. Further, in particular embodiments, Ln may include at least Gd, and optionally one or more of Lu and La, as well as at least one or more second lanthanide ions.

[0099] Furthermore, it may be possible to use semiconductor nanoparticles. For example, using a molecular synthesizer, nanocrystals of the perovskite CsPbBr3 have been shown to be capable of achieving conversion efficiencies of over 10% with excitation at 440 nm and emission in the range of 340-400 nm. See, for example, Wieghold S and Nienhaus L, Correction: Engineering 3D perovskites for photon interconversion applications. PLOS ONE 15(4): e0232196. https: / / doi.org / 10.1371 / journal.pone.0232196.

[0100] Other examples of upconversion are e.g. Lu7O6F9:Pr 3+ or Y2SiO5:Pr 3+ UV Pr like 3+ Doped crystals, or NaYF4:Yb 3+ , Tm 3+ Other examples include sub-15 nm alkaline earth rare earth fluoride UCNPs with a CaF2 shell (M 1-x Ln x F 2+x The NIR to UV / visible emission of small alkaline earth-based nanoparticles (M,MLnF) can be found in Bright Infrared-to-Ultraviolet / Visible Upconversion in Small Alkaline Earth-Based Nanoparticles with Biocompatible CaF2 Shells - Fischer - 2020 - Angewandte Chemie International Edition - Wiley Online Library. The alkaline earth (M) ranges from Ca, Sr, and Ba, MgSr, CaSr, CaBa, SrBa, and CaSrBa. The various alkaline earth host materials include Yb 3+ and Tm 3+ is doped.

[0101] See further US2010 / 0297206, which is incorporated herein by reference. Further information on upconversion can also be found, for example, in G. Blasse et al., Luminescent Materials, Springer Verlag 1994, chapter 10.1. Thus, in an embodiment, the first conversion material may comprise an upconverter luminescent material. Alternatively or in addition, the first conversion material may comprise a frequency doubling (crystal) material.

[0102] As noted above, in embodiments, the luminescent material is ABO. 12 :Ce type luminescent material, where A comprises one or more of Y, La, Gd, Tb and Lu, and B comprises one or more of Al, Ga, In and Sc.

[0103] In embodiments, the luminescent material may be comprised in a single crystal, glass or ceramic body. (Thus) in certain embodiments, the system may comprise a ceramic body, the ceramic body comprising the luminescent material.

[0104] Above, the first light-generating device has been described in more detail. The second light-generating device may in particular comprise a solid-state light source, such as a solid-state material light source. In particular, the second light-generating device may comprise one or more of a diode laser and a superluminescent diode. Furthermore, in an embodiment, the second light-generating device comprises a vertical-cavity surface-emitting laser (VCSEL).

[0105] Thus, in certain embodiments, the second light-generating device may comprise a wavelength-tunable light-generating device. Hence, in embodiments, the second light-generating device may comprise a (luminescent) colour-tunable light-generating device.

[0106] Thus, in a particular embodiment, the second light-generating device is adapted to vary, in an operation mode of the light-generating system, at least two centroid wavelengths (λ ) with a wavelength difference of at least 10 nm, such as at least 30 nm, or even at least 40 nm, at a variation frequency of at least 40 Hz, in particular at least 50 Hz, even more particularly at least 60 Hz, such as at least 80 Hz, (and in particular embodiments at least 100 Hz). 2c,1 , λ 2c,2 ) can be operated in a pulsed mode.

[0107] Thus, in certain embodiments, the second light-generating device may provide second device light having at least two different spectral power distributions at different times.

[0108] As noted above, in embodiments of the operating mode of the system, the change between the at least two different spectral power distributions may be faster than the human eye can perceive, and thus the change between the at least two different spectral power distributions may be within 0.025 seconds, such as within 0.02 seconds, or even within about 0.0167 seconds.

[0109] Thus, the second light-generating device, in an embodiment, has (at least) two spectral power distributions, a first centroid wavelength λ 2c,1 and the second centroid wavelength λ 2c,2 In some cases, the swath may be swept between those having

[0110] Furthermore, the second light-generating device may comprise an up-conversion material. Thus, the embodiments described with respect to the first light-generating device may also be applied with respect to the second light-generating device. However, these devices are particularly selected such that the first device light and the second device light have different spectral power distributions (see also above).

[0111] Assuming up-conversion in the case of the first light-generating device, the first light-generating device may in an embodiment include an IR VCSEL or an IR superluminescent diode. Assuming up-conversion in the case of the second light-generating device, the second light-generating device may in an embodiment include an IR VCSEL or an IR superluminescent diode.

[0112] In embodiments, the luminescent material may be configured to generate luminescent material light having a green, yellow or orange color point, in particular a green or yellow color point. Furthermore, in embodiments, the first light-generating device may be configured to generate blue light or red light. Furthermore, in embodiments, the second light-generating device may be configured to generate red light or blue light. Thus, in certain embodiments, (a) the first light-generating device may be configured to generate a first device light having a centroid wavelength in a blue wavelength range and the second light-generating device may be configured to generate a second device light having a centroid wavelength in a red wavelength range, or (b) the first light-generating device may be configured to generate a first device light having a centroid wavelength in a red wavelength range and the second light-generating device may be configured to generate a second device light having a centroid wavelength in a blue wavelength range.

[0113] The term "purple light" or "purple emission" particularly relates to light having a wavelength in the range of about 380 to 440 nm. The term "blue light" or "blue emission" particularly relates to light having a wavelength in the range of about 440 to 495 nm (including some purple and cyan hues). The term "green light" or "green emission" particularly relates to light having a wavelength in the range of about 495 to 570 nm. The term "yellow light" or "yellow emission" particularly relates to light having a wavelength in the range of about 570 to 590 nm. The term "orange light" or "orange emission" particularly relates to light having a wavelength in the range of about 590 to 620 nm. The term "red light" or "red emission" particularly relates to light having a wavelength in the range of about 620 to 780 nm. The term "pink light" or "pink emission" refers 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 about 490 to 520 nm. The term "amber" may refer to one or more wavelengths selected from a range of about 585-605 nm, such as about 590-600 nm. The phrase "light having one or more wavelengths within a wavelength range" and similar phrases may specifically indicate that the light (or radiation) being indicated has a spectral power distribution with at least one or more intensities at those one or more wavelengths within the wavelength range being indicated. 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 440-495 nm.

[0114] In certain embodiments, the system may further include a control system configured to control the system light, in particular by (individually) controlling the first light-generating device and the second light-generating device, in particular in dependence on one or more of an input signal of a user interface, a sensor signal of a sensor, and a timer.

[0115] The term "control" and similar terms refer in particular 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 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 include imposing a behavior on an element and monitoring the element. The control of the element may be performed by a control system, which may be denoted as 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 an embodiment, the control system and the element may not be physically coupled. The control may be performed via wired and / or wireless control. The term "control system" may also refer to a number of different control systems, particularly those that are functionally coupled, for example one control system of the number 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 may be functionally coupled to a user interface.

[0116] 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 smartphone or portable device, such as an iPhone, tablet, etc. Thus, the device is not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0117] Thus, in an embodiment, the control system may (also) be configured to be controlled by an app on a remote device. In such an embodiment, the control system of the lighting system may be a slave control system or may control 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 (e.g. a QR code reader) of the (unique) code. The lighting system may also have means for communicating with other systems or devices, such as based on Bluetooth, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology.

[0118] 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 stage, 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. Similarly, this may not exclude that one or more other modes may be performed before and / or after performing the mode.

[0119] 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 modes 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. The operating mode may also refer in embodiments to a system, or apparatus, or device that can only operate in a single operating mode (i.e. "on", without further adjustability).

[0120] Thus, in an embodiment, the control system may be dependent 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 predefined timing scheme.

[0121] It may also be desirable to adjust the spectral power composition of the system light. This may be done in particular by controlling the first light-generating device and the second light-generating device. In particular, this may be done by controlling the duty cycle of the first device light (and / or optionally the second device light). In this way, it may be possible to keep the (varied) frequency of the first device light essentially the same, but the spectral power distribution can be controlled by increasing or shortening the pulse time of each pulse for the first or second centroid wavelength. Thus, in an embodiment, the control system may be configured to control the first light-generating device by pulse width modulation, the control system being configured to control the spectral power distribution of the system light by controlling the duty cycle of the first device light in the operating mode. In particular, in an embodiment, the tunable light-generating device is configured to control in the operating mode the tunable light-generating device for the centroid wavelengths (λ 1c,1) and a first pulse of the first device light having the centroid wavelength (λ 1c,2 and a second pulse of first device light having a duty cycle of the first pulse and a duty cycle of the second pulse, wherein in the operational mode controlling the spectral power distribution of the system light includes independently controlling a duty cycle of the first pulse and a duty cycle of the second pulse.

[0122] Thus, in an embodiment, pulse width modulation may be applied to control the spectral power distribution of the first device light, and thereby the spectral power distribution of the system light. Alternative solutions for controlling the spectral power distribution of the first device light, such as by controlling the pulse height, may also be possible. Note that it may also be possible to control the spectral power distribution of the system light by controlling the second device light. Again, this may be done in a particular embodiment via pulse width modulation, but other solutions such as varying the power supplied to the second light generating device may also be applied.

[0123] Further, in certain embodiments, the luminescent material is ABO 12 :Ce type luminescent material, A may comprise one or more of Y, La, Gd, Tb and Lu, and B may comprise one or more of Al, Ga, In and Sc, the light-generation system may comprise a ceramic body, the ceramic body may comprise the luminescent material, the second light-generation device may comprise one or more of a diode laser and a superluminescent diode, the first light-generation device may be configured to generate first device light having a centroid wavelength in a blue wavelength range and the second light-generation device may be configured to generate second device light having a centroid wavelength in a red wavelength range.

[0124] Furthermore, in certain embodiments, the control system may be configured to control the system light in an operation mode of the light-generating system within a correlated color temperature range of 2000 to 6500 K, such as 2200 to 6500 K, even more particularly 2700 to 6500 K. Alternatively or additionally, the control system may be configured to control the system light in an operation mode of the light-generating system with a color rendering index of at least 80. Thus, in particular, the control system may be configured to control the system light in an operation mode of the light-generating system within a correlated color temperature range of 2700 to 6500 K with a color rendering index of at least 80.

[0125] 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, a 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.

[0126] 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 in the housing, or a housing opening, through which the system light may escape from the housing. 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 a moving image) onto a surface, such as a projection screen. The projection device may include one or more light generating systems as described herein. Thus, the present invention also provides in one aspect a light generating device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, and an optical wireless communication device, the light generating device having a light generating system as defined herein. The light-generating device may have a housing configured to accommodate or a carrier configured to support one or more elements of the light-generating system, for example in an embodiment the light-generating device may have 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 and the luminescent material. [Brief description of the drawings]

[0127] 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, in which: [Figure 1] Several embodiments and examples are illustrated diagrammatically. [Diagram 2] Several embodiments and examples are illustrated diagrammatically. [Diagram 3]Several embodiments and examples are illustrated diagrammatically. [Figure 4] Several embodiments and examples are illustrated diagrammatically. [Diagram 5] Several embodiments and examples are illustrated diagrammatically. [Figure 6] Several embodiments and examples are illustrated diagrammatically. [Figure 7] Several embodiments and examples are illustrated diagrammatically. [Figure 8a] Several embodiments and aspects are illustrated diagrammatically. [Figure 8b] Several embodiments and aspects are illustrated diagrammatically. [Figure 8c] Several embodiments and aspects are illustrated diagrammatically. [Figure 8d] Several embodiments and aspects are illustrated diagrammatically. [Figure 8e] Several embodiments and aspects are illustrated diagrammatically. [Figure 8f] Several embodiments and aspects are illustrated diagrammatically. [Figure 9a] Several embodiments and aspects are illustrated diagrammatically. [Figure 9b] Several embodiments and aspects are illustrated diagrammatically. [Figure 9c] Several embodiments and aspects are illustrated diagrammatically. [Figure 10] Some application examples are illustrated diagrammatically.

[0128] The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0129] Tunable VCSELs are available in the red to IR range, for example using MEMs. Such sources can be used to generate tunable lasers in the blue range, for example by frequency doubling. In addition, VCSELs emitting in the blue range are emerging, with efficiencies and powers already exceeding several watts.

[0130] In the following, we will explain how such tunable lasers can be used to make a BBL tunable white light source. In an embodiment, the tuning can be done using a tunable blue laser, a (possibly tunable) red laser, and a ceramic phosphor to partially convert the blue light.

[0131] Consider a Ce-doped YAG ceramic with an absorbance of 0.42 at 465 nm, close to the peak absorbance. Using the absorbance curve of Ce:YAG as a function of wavelength, we can calculate the amount of blue light that passes through the ceramic and the amount of yellow light emitted by the Ce:YAG as a result of the blue light being absorbed. Figure 1 shows the color points at discrete blue wavelengths.

[0132] For example, if a light source is used that can be swept between 440 nm and 465 nm and combined with a laser emitting at 625 nm, it is possible to create a light source that can produce any color point within the triangle shown in Figure 2. Varying the CCT along the BBL may then be possible in the range of about 3000 to 7000K.

[0133] By sweeping the blue laser light continuously between 440 nm and 460 nm and adjusting the relative intensities of the blue and red light sources, it may also be possible to move the color point continuously along the BBL between 7000K and 2700K.

[0134] In Figure 3, the use of a YAG ceramic with an absorbance of 0.56 at 465 nm is shown, using a light source that sweeps between 440 nm and 465 nm, combined with a laser emitting at 625 nm. It is possible to create a light source that can produce any color point within the triangle shown in Figure 3. This allows for a sweep between approximately 4800K and 2200K.

[0135] Table 1 shows the characteristics of white light on the BBL at the wavelengths obtained during the scan. [Table 1]

[0136] Laser-phosphor based light sources have attracted a lot of interest because of their potential to produce very high intensities. Products such as car headlights and projectors, where a laser is used to pump a phosphor, are already on the market. Laser-phosphor can also be used for other lighting applications. However, for BBL dimming, at least red, green and blue individually controllable laser-based light sources are needed.

[0137] In this specification, BBL dimming is proposed using, among other things, (at least) a high-frequency wavelength-swept laser and a ceramic phosphor. The high-frequency wavelength-swept laser can be a VCSEL that can be switched between orange and red light. By using such a light source in combination with a blue laser and a YAG / LuAG ceramic phosphor tile, the BBL can be traced, for example, for BBL dimming. Alternatively or in addition, a blue (or green) high-frequency wavelength-swept laser can be used to adjust the blue (or green) wavelength. PWM (Pulse Width Modulation) can be used to control the intensity of the laser.

[0138] Figure 4 shows a schematic of some color points available for a blue laser at about 450 nm, a green / yellow emitting material with a color point at 560 nm, and a VCSEL emitting near orange / red at various wavelengths. Note that the white light can have a controllable CCT (substantially along the blackbody locus). The various circles show color points that can be chosen depending on the centroid wavelength of the tunable device light, such as a VCSEL (shown as an example).

[0139] It is also proposed herein to use tunable lasers in the manufacture of light sources with adjustable properties, such as, inter alia, (i) color temperature, (ii) CRI and / or (iii) R9 value. It can also be used for other effects that need to be compensated for. It is proposed, inter alia, to use tunable IR vertical-cavity surface-emitting lasers (VCSELs) in combination with suitable nonlinear optical (NLO) crystals for second harmonic generation, thus obtaining tunable visible lasers.

[0140] FIG. 5 illustrates diagrammatically the spectrum of a possible tunable VCSEL.

[0141] A tunable visible laser light can be used, for example, to adjust the color point / color temperature. This can be achieved directly by the tunable visible laser light, or indirectly by pumping a phosphor, whose conversion rate depends on the pump wavelength. In the latter configuration, color separation elements (e.g. dichroics to separate the laser beams) can be used to enhance the effect. Many peaks are shown. There may also be intermediate peaks.

[0142] Alternatively, for example, it is known that the level of absorbance from garnet phosphors at a given wavelength decreases with increasing temperature. As a result, the color point of the light source changes as a function of the light intensity. A tunable blue laser can be used to compensate for the temperature absorbance and thus preserve the color point of the phosphor under changing temperatures.

[0143] In an embodiment, after frequency doubling of a tunable IR laser emitting in the wavelength range from 1240 nm to 1350 nm, a tunable red-emitting laser emitting light in the wavelength range from 620 nm to 675 nm can be obtained. Thus, a tunable light source that is tunable in the IR range, and also in the visible range, can be obtained (see further below).

[0144] In the same manner, a tunable IR emitting laser in the wavelength range of 900 nm to 990 nm and a tunable IR emitting laser in the wavelength range of 990 nm to 1140 nm can be used to manufacture a tunable laser emitting in the blue range of 450 to 495 nm and a tunable laser emitting in the green range of 495 to 570 nm, respectively.

[0145] Figure 6 shows the spectrum of a light source with a 440 nm blue laser pumping a YAG:Ce 2% phosphor in combination with a red laser light at 610 nm. For example, at CCT=3000 K, light with CRI=66, R9=-64, and a conversion efficiency of 373 lm / W can be obtained. The continuously increasing curves diagrammatically illustrate the spectral power distribution of a black body radiator at about 3000 K (see also Figure 7).

[0146] FIG. 7 shows the spectrum obtained with a blue laser at 470 nm and a red laser at 630 nm, with a higher light quality, i.e. CRI=90 and R9=92, but a lower efficacy of 330 lm / W, at the same CCT=3000K.

[0147] Referring to FIG. 8 a , in an embodiment, a light-generating system 1000 may include a first light-generating device 110 , a second light-generating device 120 , and a luminescent material 200 .

[0148] The first light-generating device 110 may be configured to generate a first device light 111. The second light-generating device 120 may be configured to generate a second device light 121. The first device light 111 and the second device light 121 have different spectral power distributions.

[0149] The luminescent material 200 may be configured to convert at least a portion of one or more of the first device light 111 and the second device light 121 to luminescent material light 201. The luminescent material 200 may be selected from the group consisting of ABO 12 :Ce 3+A may comprise one or more of the following luminescent materials: A may comprise one or more of Y, La, Gd, Tb and Lu, and B may comprise one or more of Al, Ga, In and Sc. The light-generating system 1000 may comprise a ceramic body 210, which may comprise a luminescent material 200. Reference number 550 refers to an optical system, which may include, for example, a beam-shaping element such as a collimator or a lens. Other optical systems (not shown) may also be possible. In particular, the optical system 550 refers to an optical system arranged downstream of the first light-generating device, the second light-generating device and the luminescent material.

[0150] In an embodiment, the light-generating system 1000 may further comprise a control system 300 configured to control the system light 1001 by controlling the first light-generating device 110 and the second light-generating device 120 depending on one or more of a user interface input signal, a sensor signal (of a sensor), and a timer.

[0151] 8a-8b, the first light-generating device 110 (see FIG. 8a) is configured to generate a luminance change of at least 10 nm (in the figures λ ) at a variation frequency of at least 40 Hz in the operation mode of the light-generating system 1000. 1c At least two centroid wavelengths (λ 1c,1 , λ 1c,2 ) in the wavelength-tunable light generating device 111. The variation frequency may in particular be at least 50 Hz, and even more in particular at least 60 Hz, etc. The smallest wavelength band (on the left) may have a centroid wavelength λ 1c,1 The maximum wavelength band (on the right) is the centroid wavelength λ 1c,2 Therefore, the centroid wavelength λ of at least two of these 1c,1 , λ 1c,2 is sometimes referred to as the outer centroid wavelength.

[0152] In an operating mode of the light generation system 1000, the light generation system 1000 may be configured to generate white system light 1001 including luminescent material light 201 and (at least one of) the first device light 111 and the second device light 121.

[0153] In certain embodiments of the light-generating system 1000, the first light-generating device 110 may include one or more of a vertical-cavity surface-emitting laser (VCSEL) and a superluminescent diode.

[0154] Figure 8c shows a schematic representation of an embodiment of the absorption (transmission) (left y-axis) and emission (right y-axis) of a luminescent material configured to convert a portion of the first device light (see Figure 8b) with a controllable centroid wavelength.

[0155] Figure 8d illustrates generally an embodiment in which the luminescent material is configured to convert a portion of the second device light 121. Moreover, the embodiment illustrated generally is essentially the same as the embodiment illustrated generally in Figure 8a.

[0156] FIG. 8e illustrates that the second light-generating device 120, in an operation mode of the light-generating system 1000, generates at least two centroid wavelengths (λ 1 ) with a wavelength difference of at least 10 nm, in particular with a variation frequency of at least 40 Hz, such as at least 50 Hz, such as at least 60 Hz. 2c,1 , λ 2c,2 10A, 10B, and 10C, respectively, illustrate an embodiment that may include a tunable light generating device configured to generate a second device light 121 that varies between

[0157] FIG. 8f illustrates a schematic embodiment of possible overlapping (emission) bands. The overlapping area is hatched. The percentage of overlap of the smaller band is greater than the percentage of overlap of the larger (here wider) band. In this specification, the overlap may be defined specifically for the smaller emission band. The spectral overlap of the smaller emission band with the larger emission band may be less than 20%. In particular, an emission band may be smaller than another emission band if the spectral power (integrated power) of the emission band is smaller than that of the other emission band. In FIG. 8f, the overlap may be about 50% (of the narrowband emission) (only about 10% of the broadband emission may overlap with the narrowband emission).

[0158] 9a-9b, in embodiment I, the first light-generating device 110 (a) outputs at least two centroid wavelengths (λ 1 ) with a wavelength difference of at least 20 nm at a variation frequency of at least 50 Hz in the operation mode of the light-generating system 1000. pc,1 , λ pc,2 ) can be included. In addition, a (first) upconverter material 410 is configured downstream of the tunable first light source 10 and configured to generate a first source light 11 that can be varied between at least two centroid wavelengths (λ pc,1 , λ pc,2 At least a part of the first light source light 11 that changes between at least two center wavelengths (λ 1c,1 , λ 1c,2 ) is converted into a first device light 111 that varies between

[0159] The upconverter material 410 may include one or more of an upconverter luminescent material and a frequency doubling material.

[0160] In an embodiment, the second light-generating device 120 may include one or more of a diode laser and a superluminescent diode. In an embodiment, the second light-generating device 120 may include a vertical cavity surface-emitting laser (VCSEL).

[0161] Thus, in embodiment II of Fig. 9a such an embodiment is illustrated diagrammatically, in which the second light-generating device 120 comprises a second light source 20 configured to generate a second light source light 21 varying between at least two centroid wavelengths with a wavelength difference of at least 20 nm with a variation frequency of at least 50 Hz in an operation mode of the light-generating system 1000. Furthermore, a (second) upconverter material 420 is configured downstream of the tunable second light source 20 and configured to convert at least a part of the second light source light 21 varying between at least two centroid wavelengths into a second device light 121 varying between at least two centroid wavelengths.

[0162] The first light-generating device 110 may be configured to generate a first device light 111 having a centroid wavelength in the blue wavelength range, and the second light-generating device 120 may be configured to generate a second device light 121 having a centroid wavelength in the red wavelength range. Alternatively, the first light-generating device 110 may be configured to generate a first device light 111 having a centroid wavelength in the red wavelength range, and the second light-generating device 120 may be configured to generate a second device light 121 having a centroid wavelength in the blue wavelength range.

[0163] In an embodiment, the first light source 10 may include an IR superluminescent diode or an IR VCSEL.

[0164] A control system (not shown, but see Fig. 8a or 8d) may be configured to control the first light-generating device 110 by pulse width modulation. In particular, the control system may be configured to control the spectral power distribution of the system light 1001 in an operational mode by controlling the duty cycle of the first device light 111.

[0165] The tunable light generating device, in an operating mode, has a centroid wavelength (λ 2 ) of 1000 Hz, each having a pulse frequency of at least 40 Hz. 1c,1 ) and the first pulse of the first device light 111 having a centroid wavelength (λ 1c,2) and a second pulse of first device light 111 having a duty cycle of the first pulse and a duty cycle of the second pulse, and in the operational mode controlling the spectral power distribution of the system light 1001 may include individually controlling a duty cycle of the first pulse and a duty cycle of the second pulse.

[0166] It should be noted that the control system may (also) be configured in an embodiment to control the second light-generating device by pulse width modulation.

[0167] With reference to Fig. 9c, an example of pulse width modulation is illustrated diagrammatically. By shortening the pulse width in the second embodiment, the contribution of the light delivered in the first type of pulse to the system light is reduced. In this way, the color can be adjusted, for example along the BBL. Two different pulses, shown by the open and hatched rectangles, are respectively shown with a centroid wavelength λ 1c,1 , λ 1c,2 In this manner, the light-generating device can be swept between two (or more) different spectral power distributions, thereby controlling the spectral power distribution of the system light, particularly with PWM.

[0168] The control system may be configured to control a system light 1001 having a color rendering index of at least 80 within a correlated color temperature range of 2700 to 6500K in an operational mode of the light generating system 1000.

[0169] Fig. 10 illustrates diagrammatically 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. 10 also illustrates diagrammatically an embodiment of a lamp 1 including the light-generating system 1000. Thus, Fig. 10 illustrates diagrammatically an embodiment of a lighting device 1200 selected from the group of lamps 1, lighting fixtures 2, projector devices, disinfection devices, and optical wireless communication devices, including the light-generating system 1000 as described herein. In an embodiment, such a lighting device may be a lamp 1, lighting fixture 2, projector device, disinfection device, or optical wireless communication device. The lighting device light escaping from the lighting device 1200 is indicated with reference number 1201. The lighting device light 1201 may essentially consist of the system light 1001, and thus may be the system light 1001 in certain embodiments.

[0170] The term "plurality" refers to two or more.

[0171] The terms "substantially" or "essentially" and similar terms herein will be understood by those of skill in the art. The terms "substantially" or "essentially" may also include embodiments with "entirely," "completely," "all," and the like. 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.

[0172] The term "comprises" also includes embodiments in which the term "comprises" means "consisting of."

[0173] 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 item 1 and item 2. The term "comprising" can refer in some embodiments to "consisting of," while in other embodiments it can refer to "including at least the specified species, and optionally one or more other species."

[0174] Moreover, in the specification and claims, the terms first, second, third, etc. are used to distinguish between similar elements and are not necessarily used to describe a sequential or chronological order. The terms so used are interchangeable under appropriate circumstances, and it is to be understood that the embodiments of the invention described herein are capable of operation in orders other than those described or illustrated herein.

[0175] The present specification may describe, among other things, devices, apparatus, or systems in operation. As will be apparent to one of ordinary skill in the art, the present invention is not limited to methods of operation or devices, apparatus, or systems in operation.

[0176] 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.

[0177] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0178] The use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the specification and claims, words like "comprise" 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.

[0179] The singular reference of an element does not exclude the presence of a plurality of such elements.

[0180] The invention may be implemented by means of hardware comprising several distinct elements, or by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain 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 executed on a computer, is capable of implementing (one or more embodiments of) the method as described herein.

[0181] 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.

[0182] The invention further applies to a device, an apparatus or a 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.

[0183] Various aspects described in this patent can be combined to provide additional advantages. Moreover, those skilled in the art will appreciate 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.

[0184] In particular, the present invention may provide a combination of a wavelength-swept laser and a phosphor, and a second laser, in an embodiment the wavelength-swept laser may be a red laser and the second laser may be a blue laser, or vice versa in another embodiment.

Claims

1. 1. A light generating system having a first light generating device, a second light generating device, and a luminescent material, the first light-generating device is configured to generate a first device light and the second light-generating device is configured to generate a second device light, the first device light and the second device light having different spectral power distributions; the luminescent material is configured to convert at least a portion of one or more of the first device light and the second device light to luminescent material light; the first light-generating device comprises a tunable light-generating device configured to generate a first device light that varies between at least two centroid wavelengths having a wavelength difference of at least 10 nm with a variation frequency of at least 50 Hz in an operation mode of the light-generating system; The light-generation system is configured to generate white system light comprising the luminescent material light, the first device light, and the second device light, in the operational mode of the light-generation system.

2. 10. The light-generating system of claim 1, wherein the first light-generating device comprises one or more of a vertical cavity surface-emitting laser and a superluminescent diode.

3. 2. The light-generation system of claim 1, wherein the first light-generation device comprises: (a) a tunable first light source configured to generate, in an operation mode of the light-generation system, a first light source light varying between at least two centroid wavelengths with a wavelength difference of at least 20 nm with a variation frequency of at least 60 Hz; and (b) an upconverter material configured downstream of the tunable first light source and configured to convert at least a portion of the first light source light varying between the at least two centroid wavelengths into the first device light varying between the at least two centroid wavelengths.

4. 4. The light-generating system of claim 3, wherein the upconverter material comprises one or more of an upconverter luminescent material and a frequency doubling material.

5. The luminescent material is ３ B ５ O １２ 5. The light generating system of claim 1, comprising a luminescent material of type A:Ce, 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.

6. 5. The light generating system of claim 1, comprising a ceramic body, the ceramic body comprising the luminescent material.

7. 5. The light-generating system of claim 1, wherein the second light-generating device comprises one or more of a diode laser and a superluminescent diode.

8. 5. The light-generating system of claim 1, wherein the second light-generating device comprises a tunable light-generating device configured to generate second device light varying between at least two centroid wavelengths having a wavelength difference of at least 10 nm with a variation frequency of at least 50 Hz in an operation mode of the light-generating system.

9. the first light-generating device is configured to generate a first device light having a centroid wavelength in a blue wavelength range and the second light-generating device is configured to generate a second device light having a centroid wavelength in a red wavelength range; or 5. The light-generating system of claim 1, wherein the first light-generating device is configured to generate a first device light having a centroid wavelength in a red wavelength range and the second light-generating device is configured to generate a second device light having a centroid wavelength in a blue wavelength range.

10. 5. The light-generating system of claim 1, further comprising a control system configured to control the system light by individually controlling the first light-generating device and the second light-generating device in dependence on one or more of a user interface input signal, a sensor signal, and a timer.

11. 11. The light-generating system of claim 10, wherein the control system is configured to control the first light-generating device by pulse width modulation, and wherein the control system is configured to control the spectral power distribution of the system light by controlling a duty cycle of the first device light in the operational mode.

12. 12. The light-generating system of claim 11, wherein in the operating mode, the tunable light-generating device is configured to generate a first pulse of a first device light having the centroid wavelength and a second pulse of a first device light having the centroid wavelength, each having a pulse frequency of at least 50 Hz, and in the operating mode, controlling the spectral power distribution of the system light comprises individually controlling a duty cycle of the first pulse and a duty cycle of the second pulse.

13. The luminescent material is ３ B ５ O １２ 5. The light-generating system of claim 1, wherein A comprises a luminescent material of type Ce, A comprises one or more of Y, La, Gd, Tb and Lu, and B comprises one or more of Al, Ga, In and Sc, the light-generating system comprising a ceramic body, the ceramic body comprising the luminescent material, and the second light-generating device comprises one or more of a diode laser and a superluminescent diode, the first light-generating device configured to generate first device light having a centroid wavelength in a blue wavelength range and the second light-generating device configured to generate second device light having a centroid wavelength in a red wavelength range.

14. 11. The light-generating system of claim 10, wherein the control system is configured to control the system light in an operational mode of the light-generating system to have a color rendering index of at least 80 within a correlated color temperature range of 2700 to 6500 K.

15. 5. A light-generating device selected from the group of a lamp, a luminaire, a projector device, a disinfection device and an optical wireless communication device, comprising a light-generating system according to any one of claims 1 to 4.

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