Lighting device comprising two PC-LEDS and two arrangements comprising phosphor particles

Abstract

The invention provides a light generating system comprising a first solid state light source, a first luminescent arrangement, a second solid state light source, and a second luminescent arrangement, wherein: (I) the first solid state light source comprises a first light emitting surface having a first surface area SA1; wherein the first solid state light source is configured to generate first light source light; (II) the first luminescent arrangement is configured in physical contact with at least part of the first light emitting surface; wherein the first luminescent arrangement is configured to convert at least part of the first light source light into first luminescent arrangement light; wherein the first luminescent arrangement comprises a first luminescent material configured to convert at least part of the first light source light into first luminescent material light; wherein the first luminescent arrangement light comprises the first luminescent material light; (III) the second light source comprises a second light emitting surface having a second surface area SA2; wherein the second light source is configured to generate second light source light; (IV) the second luminescent arrangement is configured in physical contact with at least part of the second light emitting surface; wherein the second luminescent arrangement is configured to convert at least part of the second light source light into second luminescent arrangement light; wherein the second luminescent arrangement comprises a second luminescent material configured to convert at least part of the second light source light into second luminescent material light; wherein the second luminescent arrangement light comprises the second luminescent material light; (V) the first luminescent material comprises a first manganese-based luminescent material comprising a luminescent material of the type MxM'2-2xAX6 doped with tetravalent manganese; wherein the second luminescent material comprises a second manganese-based luminescent material comprising a luminescent material of the type MxM'2-2xAX6 doped with tetravalent manganese; wherein M comprises an alkaline earth cation, M' comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine; (VI) the first luminescent arrangement and the second luminescent arrangement differ.

Description

[0001] LIGHTING DEVICE COMPRISING TWO PC-LEDS AND TWO ARRANGEMENTS

[0002] COMPRISING PHOSPHOR PARTICLES

[0003] FIELD OF THE INVENTION

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

[0005] BACKGROUND OF THE INVENTION

[0006] Luminescent bodies comprising phosphors are known in the art. For instance, US2018231191A1 describes a lighting system including first and second light emitting diodes. The first and second light emitting diodes have different peak wavelengths and emit light of the same color. The system further includes a third light emitting diode that emits light of a different color from the first and second light emitting diodes. A wavelength converting element is disposed in a path of light emitted by the first and second light emitting diodes.

[0007] SUMMARY OF THE INVENTION

[0008] Prior art systems comprising transition-metal-ions Mn4+activated fluoride based luminescent materials (or phosphors) have shown high luminescence efficiency. Hence, it may be desired to use such luminescent materials in high brightness lighting generating system, especially to provide an optimal (specific) luminous flux. Additionally or alternatively, it may be desired to provide a light generating system with tunable color temperature and / or tunable spectral properties. Note that, such luminescent materials may have a relatively low absorption, a limited scattering, and a susceptibility for quenching / degradation.

[0009] Especially, however, is desired to configure a lighting system such that the optical and spectral properties of the light generating system may be controlled. Furthermore, the luminescent material may generate heat in the process of conversion of light. Hence, it is also desired to provide improved thermal management. Hence, it is an aspect of the invention to provide an alternative light generating system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0010] The present invention is set out the in the appended set of independent and dependent claims.

[0011] According to a first aspect, the invention provides a light generating system comprising a first solid state light source, a first luminescent arrangement, a second solid state light source, and a second luminescent arrangement. In embodiments, the first solid state light source (or “first light source”) may comprise a first light emitting surface having a first surface area SAi. Especially, the first light source may be configured to generate first light source light (which during operation of the first light source emanates from the first light emitting surface). In further embodiments, the first light source light may comprise blue light. In embodiments, the first luminescent arrangement may be configured in physical contact with at least part of the first light emitting surface. Especially, the first luminescent arrangement may be configured to convert at least part of the first light source light into first luminescent arrangement light. Furthermore, in embodiments, the first luminescent arrangement may comprise a first luminescent material configured to convert at least part of the first light source light into first luminescent material light. In further embodiments, the first luminescent arrangement light comprises the first luminescent material light. In embodiments, the second solid state light source (or “second light source”) may comprise a second light emitting surface having a second surface area SA2. Especially, the second light source may be configured to generate second light source light (which during operation of the second light source emanates from the second light emitting surface). In further embodiments, the second light source light may comprise blue light. Further, in embodiments, the second luminescent arrangement may be configured in physical contact with at least part of the second light emitting surface. Especially, the second luminescent arrangement may be configured to convert at least part of the second light source light into second luminescent arrangement light. Furthermore, in embodiments, the second luminescent arrangement may comprise a second luminescent material configured to convert at least part of the second light source light into second luminescent material light. Especially, the second luminescent arrangement light may comprise the second luminescent material light. Moreover, in embodiments, the first luminescent material may comprise a first manganese- based luminescent material comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese. Analogously, in embodiments, the second luminescent material may comprise a second manganese-based luminescent material comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese. Herein, M comprises an alkaline earth cation, M’ comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine. Yet further, the first luminescent arrangement and the second luminescent arrangement may in embodiments differ in one or more of: (a) volume averaged particle size of the luminescent material of the type of MxM’2-2xAXe doped with tetravalent manganese, (b) manganese dopant concentration of the luminescent material of the type of MXM’2-2XAX6 doped with tetraval ent manganese, and (c) assembly type. In embodiments, it may apply that SAI / SA2<0.9. Alternatively, it may apply that SAI / SA2>1.1, such as SA1 / SA2>4. Hence, in specific embodiments, the invention provides a light generating system comprising a first solid state light source, a first luminescent arrangement, a second solid state light source, and a second luminescent arrangement, wherein: (I) the first light source comprises a first light emitting surface having a first surface area SAi; wherein the first light source is configured to generate first light source light (which during operation of the first light source emanates from the first light emitting surface) (wherein the first light source light comprises blue light); (II) the first luminescent arrangement is configured in physical contact with at least part of the first light emitting surface; wherein the first luminescent arrangement is configured to convert at least part of the first light source light into first luminescent arrangement light; wherein the first luminescent arrangement comprises a first luminescent material configured to convert at least part of the first light source light into first luminescent material light; wherein the first luminescent arrangement light comprises the first luminescent material light; (III) the second light source comprises a second light emitting surface having a second surface area SA2; wherein the second light source is configured to generate second light source light (which during operation of the second light source emanates from the second light emitting surface) (wherein the second light source light comprises blue light); (IV) the second luminescent arrangement is configured in physical contact with at least part of the second light emitting surface; wherein the second luminescent arrangement is configured to convert at least part of the second light source light into second luminescent arrangement light; wherein the second luminescent arrangement comprises a second luminescent material configured to convert at least part of the second light source light into second luminescent material light; wherein the second luminescent arrangement light comprises the second luminescent material light; (V) the first luminescent material comprises a first manganese-based luminescent material comprising a luminescent material of the type MxM’2-2xAX6 doped with tetravalent manganese; wherein the second luminescent material comprises a second manganese-based luminescent material comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese; wherein M comprises an alkaline earth cation, M’ comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine; (V) the first luminescent arrangement and the second luminescent arrangement differ in one or more of: (a) volume averaged particle size of the luminescent material of the type of MxM’2-2xAXe doped with tetraval ent manganese; (b) manganese dopant concentration of the luminescent material of the type of MxM’2-2xAX6 doped with tetravalent manganese, and (c) assembly type; and (VI) optionally SA1 / SA2>4. In this way, the invention may provide a lighting device comprising two pc-LEDs and two (luminescent) arrangements comprising phosphor particles. Note that the term pc-LED may refer to “phosphor converted LED”, wherein e.g. a coating or layer of luminescent material may be applied on the light emitting surface of the light source. These aspects are defined further below.

[0012] Such a light generating system may comprise at least two light sources (with differing surface areas of the two different light emitting surfaces) and at least two types of luminescent arrangements. Especially, the luminescent arrangement may facilitate in combination with a light source (especially a blue light source), the generation of white light (e.g., by mixing blue light and yellow (luminescent material) light). Note that the two light sources may in embodiments differ in the centroid wavelength of generated light source light. Furthermore, depending on the luminescent arrangement, the centroid wavelength of the converted luminescent arrangement light may also be different. Hence, with two different types of light sources and two different types of luminescent arrangements, respectively, the percentage of blue contribution to the generated light and / or the percentage of luminescent material light contribution to the generated light may be (individually) controlled. In this way, in embodiments, the correlated color temperature (CCT) of the light provided may be controlled. Further, with such a light generating system, by combining device light from the (at least) two light sources and the (at least) two luminescent materials, an improved color rendering index (CRI) may be provided. Furthermore, the extent of conversion of the device light to luminescent material light may be controlled by varying the dopant concentration and / or the volume averaged particle size of the luminescent material. By varying the aforementioned parameters, the spectral properties of the light generated by the system may be controlled. Note also that the present invention may comprise two light sources which may differ in their light emitting surface areas. Two light sources with differing surface areas may be relatively cheaper than two large light sources with the same light emitting surface areas. However, with a such a configuration it may yet be possible to provide a homogenous spotlight with relatively limited contour effects in the spotlight. Further, the use of different sized light emitting surface areas may allow controlling (optical) properties of the system light and / or may allow application of different particle size phosphors in an efficient way. Other advantages may include improved thermal management. Since the light sources may be mounted on the same substrate (e.g., a printed circuit board (PCB)), it may be desired to prevent uneven heating of the substrate. This may be limited (or completely prevented) by the choice of assembly type, for example by a luminescent arrangement comprising a ceramic body may facilitate conducting and spreading heat over a large surface area preventing the development of local hot spots.

[0013] As mentioned above, the light generating system comprises a first solid state light source, a first luminescent arrangement, a second solid state light source, and a second luminescent arrangement. Here below, the features of the invention are discussed in embodiments.

[0014] In embodiments, the first light source may generate first light source light. Further, in embodiments, the first light source may comprise a first light emitting surface having a first surface area SAi. The light emitting surface may especially refer to the surface of the first light source via which the first light source light may emanate (or escape from) during the operation of the first light source. Typically, in embodiments, the first light source light may comprise blue light. However, the first light source is not limited to producing blue light and in other embodiments, the first light source light may (also) comprise light from other wavelength ranges.

[0015] Analogous to the first light source, the second light source may be configured to generate second light source light. In embodiments, the second light source may comprise a second light emitting surface having a second surface area SA2. Especially, the second light source light may during operation of the second light source emanate (or escape from) the second light emitting surface. In further embodiments, the second light source light may comprise blue light. As with the first light source, the second light source is not limited to producing blue light and in other embodiments, the second light source light may also comprise light from other wavelength ranges, such as violet light, green light, yellow light, orange light and red light. Especially, however the first light source and / or the second light source are configured to generate blue (first and / or second, respectively) light source light.

[0016] The terms “violet light” or “violet emission” especially relates to light having a wavelength in the range of about 380-440 nm. The terms “blue light” or “blue emission” especially relates to light having a wavelength in the range of about 440-495 nm (including some violet and cyan hues). The terms “green light” or “green emission” especially relate to light having a wavelength in the range of about 495-570 nm. The terms “yellow light” or “yellow emission” especially relate to light having a wavelength in the range of about 570- 590 nm. The terms “orange light” or “orange emission” especially relate to light having a wavelength in the range of about 590-620 nm. The terms “red light” or “red emission” especially relate to light having a wavelength in the range of about 620-780 nm. The term “pink light” or “pink emission” refers to light having a blue and a red component. The term “cyan” may refer to one or more wavelengths selected from the range of about 490-520 nm. The term “amber” may refer to one or more wavelengths selected from the range of about 585-605 nm, such as about 590-600 nm. The phrase “light having one or more wavelengths in a wavelength range” and similar phrases may especially indicate that the indicated light (or radiation) has a spectral power distribution with at least intensity or intensities at these one or more wavelengths in the indicated wavelength range. For instance, a blue emitting solid state light source will have a spectral power distribution with intensities at one or more wavelengths in the 440-495 nm wavelength range.

[0017] Further, in embodiments, the first luminescent arrangement may be configured to convert at least part of the first light source light into first luminescent arrangement light. Hence, the first luminescent arrangement may be configured in a light receiving relationship with the first light source. Not that in embodiments, at least a part of the first light source light may be outcoupled via the first luminescent arrangement. Especially, the first luminescent arrangement may comprise a first luminescent material configured to convert at least part of the first light source light into first luminescent material light. Furthermore, the first luminescent arrangement light may especially comprise the first luminescent material light.

[0018] Luminescent material may at least partly convert a first radiation (e.g., blue light) into a second radiation (e.g., yellow light). Especially, the second radiation may have a spectral distribution different from that of the first radiation. During operation a part of the first radiation may be transmitted without a conversion and another part of the first radiation may undergo a conversion to the second radiation. Hence, the resulting radiation may be a combination of the first radiation and the second radiation. For instance, a percentage of the blue light may undergo conversion to yellow light (and the remainder may remain as unconverted blue light), and hence white light (comprising (both) blue light and yellow light) may be provided. See also further below for a detailed explanation and delineation of suitable luminescent material.

[0019] In embodiments, the first light emitting surface may be an epitaxial surface of the first light source. Likewise, in embodiments, the second light emitting surface may be an epitaxial surface of the second light source. Epitaxy may refer to the deposition of an overlayer on a substrate, typically on a crystalline substrate. The overlayer is called an epitaxial film or epitaxial surface or epitaxial layer. Especially, epitaxy may improve the performance of light sources, especially solid state light sources. By depositing a doped epitaxial surface over a heavily-doped silicon substrate, a higher breakdown voltage across the collector-substrate junction may be achieved, while yet maintaining low collector resistance. Hence, in specific embodiments, the first light emitting surface is an epitaxial surface of the first solid state light source, and the second light emitting surface is an epitaxial surface of the second solid state light source.

[0020] In embodiments, the first light source may be configured on a substrate and the first luminescent arrangement may be configured over at least a part of the first light emitting surface. Likewise, in embodiments, the second light source may be configured on a substrate and the second luminescent arrangement may be configured over at least a part of the second light emitting surface. Note that in embodiments, the substrate may be a printed circuit board (PCB). Further, in embodiments, the first (solid state) light source and the second (solid state) light source are functionally coupled to a same printed circuit board (PCB). Here, the term functionally coupled refers to attaching an electrical component, such as a light source, to a PCB such that the electrical component is physically secured to the PCB and electrically powered via the PCB. In further embodiments, the PCB may facilitate controlling the electrical component and / or operating the electrical component in one or more operational modes. In this way, the first light source and the second light source may be optimally positioned to distribute heat over the printed circuit board. This may facilitate better thermal management of the light generating system.

[0021] In embodiments, the first luminescent arrangement may be configured in physical contact with at least part of the first light emitting surface. In some embodiments, the first luminescent material may be configured over only a part of the first light emitting surface. In embodiments, the first luminescent arrangement may cover at least 60%, such as at least 75%, especially at least 90%, of the first light emitting surface. However, in further embodiments, the first luminescent material surface may also be configured over the entire surface area of the first light emitting surface. This may provide the benefit of controlling the percentage of the first light source light converted to the first luminescent arrangement light.

[0022] Analogous to the first luminescent arrangement, the second luminescent arrangement may be configured to convert at least part of the second light source light into second luminescent arrangement light. Hence, the second luminescent arrangement may be configured in a light receiving relationship with the second light source. Note that in embodiments, at least a part of the second light source light may be outcoupled via the second luminescent arrangement. Especially, the second luminescent arrangement may comprise a second luminescent material configured to convert at least part of the second light source light into second luminescent material light. Furthermore, the second luminescent arrangement light may comprise the second luminescent material light. Further, in embodiments, the light generating system may comprise the second luminescent arrangement configured in physical contact with at least part of the second light emitting surface. As in the case of the first luminescent arrangement, the surface area of the second light emitting surface over which the second luminescent arrangement is configured may be varied. In some embodiments, the second luminescent arrangement may be arranged over only a part of the second light emitting surface. In embodiments, the second luminescent arrangement may cover at least 60%, such as at least 75%, especially at least 90%, of the second light emitting surface. In further embodiments, the second luminescent arrangement may also cover the entire surface of the second light emitting surface. Note that the general term “luminescent material” may refer to both the first luminescent material and the second luminescent material. Likewise, the general term “luminescent arrangement” may apply to both the first luminescent arrangement and the second luminescent arrangement.

[0023] In further embodiments, the first luminescent material may comprise a first manganese-based luminescent material comprising a luminescent material of the type MXM’2- 2XAXe doped with tetravalent manganese. Analogously, the second luminescent material may comprise a second manganese-based luminescent material comprising a luminescent material of the type of MxM’2-2XAXe doped with tetravalent manganese. Here, M comprises an alkaline earth cation, M’ comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine.

[0024] The first luminescent arrangement and the second luminescent arrangement may differ in a plurality of different ways. In summary, the first luminescent arrangement and the second luminescent arrangement differ in one or more of: (a) volume averaged particle size of the luminescent material of the type of MxM’2-2xAXe doped with tetraval ent manganese; (b) manganese dopant concentration of the luminescent material of the type of MxM’2-2xAXe doped with tetravalent manganese, and (c) assembly type.

[0025] Herein, the first luminescent arrangement and the second luminescent arrangement may especially differ in the volume averaged particle size of the luminescent material of the type of MxM’2-2xAX6 doped with tetraval ent manganese. The term volume averaged particle size is known in the art. The volume averaged particle size takes into account the volume contribution of each particle in the calculation. For example, a relatively larger particle may have a higher impact on determining the (volume) averaged particle size in comparison to relatively smaller particles. Varying the size of the particles may especially provide control over the extent of light scattering. Especially, smaller particles may provide relatively higher light scattering as compared to larger particles. The equivalent spherical diameter (or ESD) of an (irregularly) shaped object is the diameter of a sphere of equivalent volume. Hence, the equivalent spherical diameter (ESD) of a cube with a side a is 2 * a * ^ / 3 / (4 * n). Would a sphere in an xyz-coordinate system with a diameter D be distorted to any other shape (in the xyz-plane), without changing the volume, than the equivalent spherical diameter of that shape would be D.

[0026] In further embodiments, the first luminescent arrangement and the second luminescent arrangement may differ in or more (other) features or parameters. Especially, the first luminescent arrangement and the second luminescent arrangement may differ in the dopant concentration of the luminescent material of the type of MxM’2-2xAX6 doped with tetravalent manganese. In embodiments, relative to a total molar amount of elements of the type A (i.e., the tetravalent cation) in the first luminescent material and the second luminescent material, at most 20%, such as at most 15%, especially at most 10%, consists of tetravalent manganese. Further, in embodiments, relative to a total molar amount of elements of the type A (i.e., the tetravalent cation) in the first luminescent material and the second luminescent material, at least 0.1%, such as at least 0.5%, especially at least 1%, consists of tetravalent manganese. The dopant concentration may especially refer to the molar concentration or mole percentage, which is derivable from the below indicated m value (i.e. m*100% in MxM’2-2xAi-mMnmX6 doped with tetravalent manganese relative to the volume of the luminescent arrangement. The percentage of the first light converted to the first luminescent material light may depend on the manganese dopant concentration of the first luminescent material. Likewise, the percentage of the second light source light converted to the second luminescent material light may depend on the manganese dopant concentration of the second luminescent material. In embodiments, the second manganese-based luminescent material may comprise at least 0.2 percent points (or percentage points), such as at least 0.5 percent points, especially at least 1 percent points more manganese than the first manganese- based luminescent material. Hence, in specific embodiments, relative to a total molar amount of elements of the type A in the luminescent materials 0.1-15% consists of tetravalent manganese, wherein the second manganese-based luminescent material comprises at least 0.2 percent points more manganese than the first manganese-based luminescent material. Typically, a higher manganese dopant concentration may provide a relatively shorter optical path for light transmitted via the luminescent arrangement and thus, a higher percentage conversion of light source light to luminescent material light may be achieved.

[0027] Additionally, or alternatively, in embodiments, the manganese dopant concentration may be selected in dependence of the dimensions of the luminescent arrangement. Especially, the first luminescent arrangement and the second luminescent arrangement may comprise a first layer thickness (Hi) and a second layer thickness (H2), respectively. In further embodiments, the first layer thickness (Hi) may be larger than the second layer thickness (H2). Especially, it may apply that H2 / HI<0.9, such as H2 / HI<0.8, especially H2 / HI<0.7. Alternatively, in embodiments, the first layer thickness (Hi) may be smaller than the second layer thickness (H2). Especially, it may apply that H2 / HI>1.1, such as H2 / HI>1.2, especially H2 / HI>1.3. In specific embodiments, the first luminescent arrangement comprises a first layer thickness (Hi), and wherein the second luminescent arrangement comprises a second layer thickness (H2), wherein H2 / HI<0.9 or H2 / HI>1.1. Note that, a luminescent arrangement with a relatively lower thickness may require a relatively higher manganese dopant concentration for sufficient absorption (and subsequent conversion to luminescent material light).

[0028] Further, in embodiments, the first luminescent arrangement and the second luminescent arrangement may differ in assembly type. In embodiments, the assembly type may be selected from the group of (i) an encapsulant comprising particulate luminescent material, (ii) a layer comprising particulate luminescent material, and (iii) a ceramic body comprising luminescent material or a glass body comprising luminescent material or a single crystal body comprising luminescent material. See also further below for delineation of the different assembly types. Hence, in embodiments the term “luminescent arrangement” may refer to en encapsulant, a layer, or a ceramic body. The term “encapsulant comprising particulate luminescent material” may e.g. refer to a dome or a body. The term “layer comprising particulate luminescent material” may refer to a layer, optionally including other material, like encapsulant, provided as layer. Luminescent material layers are known in the art.

[0029] As mentioned above, the surface areas of the first light emitting surface and the second light emitting surface may be different. In embodiments, the first surface area SAi (of the first light emitting surface) may be larger than the second surface area SA2 (of the second light emitting surface). Especially, it may apply that SAI / SA2>4, such as SAI / SA2>6, especially SAI / SA2>10. Furthermore, in embodiments, the first light emitting surface may have one or more dimensions of at least 300 pm, such as at least 600 pm, especially at least 1000 pm. Hence, in embodiments, the first light emitting surface may have dimensions of at least 300x300 pm2, such as at least 600x600 pm2, especially at least 1000x1000 pm2. The second light emitting surface may have one or more dimensions of at maximum 300 pm, such as at maximum 200 pm, especially at maximum 100 pm. Hence, in embodiments, the second light emitting surface may have dimensions of at most 200x200 pm2, such as at most 100x100 pm2, especially at most 50x50 pm2. Note that the first light emitting surface and / or the second light emitting surface are not limited to square cross-sections. For example, the first light emitting surface may have a square cross-section with dimensions 300x300 pm2, or alternatively even a rectangular cross-section with dimensions of 500x1000 pm2. Likewise, the second light emitting surface may have a square cross-section with dimensions 200x200 pm2, or alternatively even a rectangular cross-section with dimensions of 75x150 pm2. In specific embodiments, the first light emitting surface has one or more dimensions of at least 300 pm, and wherein the second light emitting surface has one or more dimensions of at maximum 100 pm, and wherein SAl / SA2>10. However, in other embodiments, the first surface area SAi may (also) be smaller than the second surface area SA2. Especially, it may apply that SAI / SA2<0.9, such as SAI / SA2<0.8, especially SAI / SA2<0.7. Yet, in specific embodiments the dimensions of the cross-sections of the first light emitting surface and the second light emitting surface may be selected from the range of 20 pm - 20 mm, though other values may also be chosen. Further, in specific embodiments the surface areas of the cross-sections of the first light emitting surface and the second light emitting surface may be selected from the range of 400 pm2- 400 mm2, though other values may also be chosen.

[0030] Here below some further configurations of the light generating system are discussed in embodiments.

[0031] In embodiments, the first luminescent arrangement and the second luminescent arrangement may be (individually) selected from the group of an encapsulant comprising particulate luminescent material and a layer comprising particulate luminescent material. The encapsulant may comprise a matrix material within which particulate luminescent material may be embedded. Especially, in the encapsulant, the luminescent particles may be dispersed within the matrix material. In further embodiments, at least a part of the first light source and / or at least a part of the second light source may (individually) be encapsulated by the encapsulant. The layer may in embodiments be a layer comprising a dispersion of luminescent particles. Especially, the layer (comprising particulate luminescent material) may (individually) be applied on at least a part of the light emitting surface of the first light source and / or at least on a part of the surface of the second light source. In further embodiments, the layer may in itself not be applied on (at least a part of) the surface of the light source (i.e., the first light source and / or the second light source), but rather the layer may be embedded in an encapsulant and subsequently applied on (at least a part of) the light source. With such a configuration (i.e., layer embedded in an encapsulant) a more homogenous volumetric particle dispersion within said encapsulant may be achieved.

[0032] Furthermore, in embodiments comprising the encapsulant (comprising particulate luminescent material) and / or the layer (comprising particulate luminescent material), the particulate luminescent material may comprise a manganese-based luminescent material. That is, the first luminescent arrangement may comprise a first manganese-based luminescent material. Furthermore, in embodiments, the first manganese-based luminescent material may have a volume averaged particle size Di. In embodiments, Di may be at least 5 pm, such as at least 7.5 pm, especially at least 10 pm. Furthermore, in embodiments, Di may be at most 100 pm, such as at most 50 pm, especially at most 40 pm. Likewise, in embodiments, the second luminescent material may comprise the second manganese-based luminescent material. Especially, the second luminescent arrangement may comprise a second volume-averaged particle size D2. In embodiments, D2 may be at most 5 pm, such as at most 2 pm, especially at most 1 pm. Furthermore, in embodiments, D2 may be at least 20 nm, such as at least 50 nm, especially at least 100 nm. In specific embodiments, Dl> 5 pm, and wherein D2 < 1 pm. Further, in embodiments, it may apply that D1 / D2>1.1, such as Dl / D2>1.5, especially Dl / D2>2, more especially Dl / D2>3. In specific embodiments, the assembly type for both luminescent arrangements is selected from the group of (i) an encapsulant comprising particulate luminescent material and (ii) a layer comprising particulate luminescent material; wherein the first manganese-based luminescent material has a first volume averaged particle size Di, wherein the second manganese-based luminescent material has a second volume averaged particle size D2, wherein DI / D2>2. With a larger particle size, a lower percentage of light scattering in the first luminescent arrangement may be achieved compared to the second luminescent arrangement. In this way, the optical properties of the outcoupled light from the light generating system may be controlled.

[0033] As mentioned above, the first luminescent arrangement may be different in configuration from the second luminescent arrangement in embodiments. In further embodiments, one of the two scenarios may apply. In a first scenario, in embodiments, the first luminescent arrangement comprises a first ceramic body or a first glass body or a first single crystal body comprising the first manganese-based luminescent material, and the second luminescent arrangement comprises an assembly type selected from the group of (i) an encapsulant comprising particulate luminescent material, and (ii) a layer comprising particulate luminescent material. Alternatively, in a second scenario, in embodiments, the second luminescent arrangement comprises a second ceramic body or a second glass body or a second single crystal body comprising the second manganese-based luminescent material, and the first luminescent arrangement comprises an assembly type selected from the group of (i) an encapsulant comprising particulate luminescent material, and (ii) a layer comprising particulate luminescent material. Hence, several configurations of the light generating system may be possible in dependence of the desired optical properties and thermal management. With the ceramic body, the glass body and the single crystal body a larger (geometric) volume may be achieved (as compared to an encapsulant and / or a layer). This may facilitate configuring larger luminescent particles in the luminescent arrangement, which may provide higher absorption with relatively lower scattering of light source light. Furthermore, one of the two scenarios may be selected to provide improved thermal management of the light generating system, such as to achieve an overall lower operating temperature.

[0034] Returning to aspects and features relating to the one or more types of luminescent materials configured in the light generating system, here below, a description of luminescent materials is provided. Note that the general term “luminescent material” may refer to the first luminescent material and / or the second luminescent material.

[0035] The general term “luminescent material” may especially refer to a material that can convert first radiation, especially one or more of UV radiation and blue radiation, into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in so-called down-conversion. In specific embodiments, however, the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in so-called up-conversion. In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material emits radiation. In general, the luminescent material will be a down converter, i.e. radiation with a smaller wavelength is converted into radiation with a larger wavelength ( x< m), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation with a larger wavelength is converted into radiation with a smaller wavelength (Xex>Xem). In embodiments, the term “luminescence” may refer to phosphorescence. In embodiments, the term “luminescence” may also refer to fluorescence. Instead of the term “luminescence”, also the term “luminescent material light” or “emission” may be applied. Hence, the terms “first radiation” and “second radiation” may refer to excitation radiation and emission (radiation), respectively. Likewise, the term “luminescent material” may in embodiments refer to phosphorescence and / or fluorescence. The term “luminescent material” may also refer to a plurality of different luminescent materials. Examples of possible luminescent materials are indicated below. Hence, the term “luminescent material” may in specific embodiments also refer to a luminescent material composition. Instead of the term “luminescent material” also the term “phosphor” may be applied. These terms are known to the person skilled in the art.

[0036] In embodiments, luminescent materials are selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium.

[0037] In specific embodiments, the first luminescent material and / or the second luminescent material (individually) comprise a luminescent material selected from the type A3BsOi2:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium (Y) or lutetium (Lu) and wherein B comprises at least aluminum (Al). Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Yi-xLux)3B50i2:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Yi.xLux)3A150i2:Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Yo.iLuo.sgCeo.o sALOn. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art.

[0038] In specific embodiments, the first luminescent material and / or the second luminescent material (individually) comprise a primary luminescent material of the type (YxiiLuxnA’xisCexi^sBsOn and a secondary luminescent material of the type (Yx2iLux22A’x23CeX24)3B5Oi2, wherein A’ comprises one or more of La, Gd, and Tb, wherein B comprises one or more of Al, Ga, In and Sc; and wherein: (I) xn+xi2+xi3+xi4=l; xn+xi2>0; 0<xi3<l; and 0.001<xi4<0.1; (II) X2i+x22+x23+x24=l; X2i+x22>0; 0<X23<l; and 0.001<X24<0.1; and (III) xn>X2i and X22>xi2. In embodiments, the secondary luminescent material may thus comprise on a molar basis more Lu than the primary luminescent material. Further, in embodiments, the primary luminescent material may comprise on a molar basis more Y than the secondary luminescent material, xn > X21. In embodiments, X12 may be equal to zero. Further, in embodiments, one or more of X12, X13, and X23 may be equal to zero. In embodiments, X14 may be equal to X24. Yet, in embodiments, X14 may be different from X24, wherein (both) X14 and X24 may be individually selected from the range of 0.001-0.1. Hence, in embodiments, the luminescent material may comprise a primary luminescent material such as (YxiiLuxnCexi^BsOn (wherein xn+ xn+ xu = 1) and a secondary luminescent material such as (YX2iLux22CeX24)3B5Oi2 (wherein X21+ X22+ X24 = 1), wherein X22 > X12, and wherein in specific embodiments X12 = 0. Hence, in specific embodiments, the luminescent material may comprise at least two luminescent materials of the type AsBsOn Ce3, wherein: (a) a primary luminescent material of this type may comprise on a molar basis more Y than a secondary luminescent material of this type, and (b) the secondary luminescent material of this type may comprise on a molar basis more Lu than the primary luminescent material of this type.

[0039] The term “tetravalent manganese” refers to Mn4+. This is a well-known luminescent ion. In the formula as indicated above, part of the tetravalent cation A (such as Si) is being replaced by manganese. Hence, M’xM2-2xAX6 doped with tetravalent manganese may also be indicated as M’xM2-2xAi-mMnmX6. The mole percentage of manganese, i.e. the percentage it replaces the tetravalent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12.

[0040] A comprises a tetravalent cation, and preferably at least comprises silicon. A may optionally (further) comprise one or more of titanium (Ti), germanium (Ge), stannum (Sn) and zinc (Zn). Preferably, at least 80%, even more preferably at least 90%, such as at least 95% of M consists of silicon. Hence, in a specific embodiment, M’xM2-2xAX6 may also be described as M’xM2-2xAi-m-t-g-s-zrMnmTitGegSnsZrzrX6, wherein m and x are as indicated above, and wherein t,g,s,zr are each individually preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05, wherein t+g+s+zr is smaller than 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0- 0.05, and wherein A is especially Si. X is preferably fluorine (F).

[0041] As indicated above, M relates to monovalent cations, but preferably at least comprises potassium and / or rubidium. Other monovalent cations that may further be comprised by M can be selected from the group consisting of lithium (Li), sodium (Na), cesium (Cs) and ammonium (NH4+). In an embodiment, preferably at least 80%(i.e. 80% of all moles of the type M), even more preferably at least 90%, such as 95% of M consists of potassium and / or rubidium. Especially, in these embodiments, x is thus zero.

[0042] Hence, in a specific embodiment, M’xM2-2xAX6 can also be described as (Ki-r-i- n-c-nhRbrLiiNanCsc(NH4)nh)2AX6, wherein r is in the range of 0-1, wherein l,n,c,nh are each individually preferably in the range of 0-1, preferably 0-0.2, especially 0-0.1, even more especially 0-0.05, and wherein r+ 1+n+c+nh is in the range of 0-1, especially 1+n+c+nh is smaller than 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05. X is preferably fluorine (F). As indicated above, instead of or in addition to the alkaline cation(s), also one or more alkaline earth cations may be present. Hence, in a specific embodiment, M’XM2- 2XAXe can also be described as MgmgCaCaSrsrBaba(KkRbrLiiNanCsc(NH4)nh)2AX6, with k, r, 1, n, c, nh each individually being in the range of 0-1, wherein mg, ca, sr, ba are each individually in the range of 0-1, and wherein mg+ca+sr+ba+k+ r+ l+n+c+nh=l. In embodiments, k=l, and the others (mg, ca, sr, ba, r, 1, n, c, nh) are zero.

[0043] As indicated above, X relates to a monovalent anion, but at least comprises fluorine. Other monovalent anions that may optionally be present may be selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I). Preferably, at least 80%, even more preferably at least 90%, such as 95% of X consists of fluorine. Hence, in a specific embodiment, M’xM2-2xAX6 can also be described as M’xM2-2XA(Fi.ci-b-iClciBrbIi)6, wherein cl,b,i are each individually preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05, and wherein cl+b+i is smaller than 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05. Especially, X essentially consists of F (fluorine).

[0044] Hence, M’xM2-2XAX6 can also be described as (Ki-r-i-n-c-nh RbrLiiNanCsc(NH4)nh)2Sii-m-t-g-s-zrMnmTitGegSnsZrzr(Fi-ci-b-iClciBrbIi)6, with the values for r,l,n,c,nh,m,t,g,s,zr,cl,b,i as indicated above. X is preferably fluorine (F).

[0045] Even more especially, M’xM2-2XAX6 can also be described as MgmgCacaSrsrBaba(KkRbrLilNanCsc(NH4)nh)2Sil.m-t-g-s-zrMnmTitGegSnsZrzr(F l-cl-b-iClclBrbIi)6, with k, r, 1, n, c, nh each individually being in the range of 0-1, wherein mg, ca, sr, ba are each individually in the range of 0-1, wherein mg+ca+sr+ba+k+ r+ l+n+c+nh=l, and with the values for m,t,g,s,zr,cl,b,i as indicated above. X is preferably fluorine (F).

[0046] In an embodiment, M’xM2-2XAX6 comprises BGSiFe (indicated herein also as KSiF system). As indicated above, in another preferred embodiment, M’xM2-2XAX6 comprises kRbSiFe (i.e. r=0.5 and l,n,c,nh,t,g,s,zr,cl,b,i are 0) (herein also indicated as K,Rb system). As indicated above, part of silicon is replaced by manganese (i.e. the formula may also be described as K2Sii-mMnmF6 or kRbSii-mMnmF6, with m as indicated above, or as kRbSiFe:Mn and BGSiFe Mn, respectively). As manganese replaces part of a host lattice ion and has a specific function, it is also indicated as “dopant” or “activator”. Hence, the hexafluorosilicate is doped or activated with manganese (Mn4+). Here below, M’xM2-2XAX6 is also indicated as M’xM”2-2XAX6. In specific embodiments, the indication M’xM2-2XAX6 may refer to one or more of (K,Rb)2SiFe:Mn4+, (K,Rb)2TiFe:Mn4+, K2(Si,Ti)Fe:Mn4+, and Rb2(Si,Ti)Fe:Mn4+, such as one or more of K2TiFe:Mn4+, of K2SiFe:Mn4+, and of Rb2SiFe:Mn4+. In embodiments, the first luminescent material and / or second luminescent material may comprise (K,Rb)2SiFe:Mn4+. Further, in embodiments, the first luminescent material and / or second luminescent material may comprise K2(Si,Ti)Fe:Mn4+. In specific embodiments, the first luminescent material and / or second luminescent material may especially comprise K2SiFe:Mn4+. Alternatively or additionally, in embodiments the first luminescent material and / or second luminescent material may comprise K2TiFe:Mn4+. As can be derived from the above, “Si,Ti” may indicate one or more of Si and Ti. The luminescent material may also be coated, as also described in WO2013121355A1.

[0047] Returning to embodiments of the light generating system. In embodiments, the light generating system may comprise a first light generating device. Especially, the first light generating device may comprise the first solid state light source and the first luminescent arrangement. Further, in embodiments, the light generating system may comprise a second light generating device. Especially, the second light generating device may comprise the second solid state light source and the second luminescent arrangement. In specific embodiments, the light generating system may comprise both the first light generating device and the second light generating device. In embodiments, the first light generating device may be configured to generate first device light. Especially, the first device light may be white light. Likewise, in embodiments, the second light generating device may be configured to generate second device light. Especially, the second device light may be white light. Furthermore, in embodiments, the first device light and the second device light may have a correlated color temperature difference of at least 500 K. In this way, the CCT of the system light (comprising both the first device light and the second device light) may be controlled in various ways. By controlling the operation of the first device light (e.g., the brightness) the contribution of the first device light to the system light may especially be controlled. Analogously, by controlling the operation of the second device light, the contribution of the second device light to the system light may especially be controlled. For instance, a primary first device may be configured to generate first device light having a primary CCT Tl and a secondary first device may be configured to generate first device light having a secondary CCT T2, wherein |T 1 -T2|>500 K. In (other) embodiments, especially |T1 -T2|>1000 K. The term “white light” herein, is known to the person skilled in the art. It especially relates to light having a correlated color temperature (CCT) between about 1500 K and 20000 K, such as between 1700 and 20000 K, especially in embodiments 2700-20000 K, for general lighting especially in the range of about 1800 K and 6500 K. Yet further, in embodiments the correlated color temperature (CCT) is especially within about 15 SDCM (standard deviation of color matching) from the BBL (black body locus), especially within about 10 SDCM from the BBL, even more especially within about 5 SDCM from the BBL. The terms CCT and CRI are known in the art.

[0048] As mentioned above, it may be desired to control the spectral distribution of the system light. This may be facilitated by controlling the one or more different light sources. In specific embodiments, the light generating system comprises a control system, wherein the control system is configured to individually control the first light source and the second light source; wherein the control system is configured to control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer.

[0049] The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and / or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface. The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system.

[0050] The system, or apparatus, or device may execute an action in a “mode” or “operation mode” or “mode of operation” or “operational mode”. The term “operational mode may also be indicated as “controlling mode”. Likewise, in a method an action or stage, or step may be executed in a “mode” or “operation mode” or “mode of operation” or “operational mode”. This does not exclude that the system, or apparatus, or device may also be adapted for providing another controlling mode, or a plurality of other controlling modes. Likewise, this may not exclude that before executing the mode and / or after executing the mode one or more other modes may be executed.

[0051] However, in embodiments a control system may be available, that is adapted to provide at least the controlling mode. Would other modes be available, the choice of such modes may especially be executed via a user interface, though other options, like executing a mode in dependence of a sensor signal or a (time) scheme, may also be possible. The operation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability).

[0052] Hence, in embodiments, the control system may control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer. The term “timer” may refer to a clock and / or a predetermined time scheme.

[0053] As mentioned above, the light generating system may comprise the first light source and the second light source. Especially, the first light source may comprise a solid state light source. In embodiments, the second light source may comprise a solid state light source. The term “light source” may especially refer to an LED (light emissive diode). In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs. Further, the term “light source” may in embodiments also refer to a so-called chip-on-board (COB) light source. The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller than 2 mm, such as in the range of e.g. 0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 gm - 1 mm. Herein, the term p size or micro LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.

[0054] Further, the term “light source” may refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a laser diode, a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser (EEL), a photonic crystal surface emitting laser (PCSEL), a vertical external cavity surface emitting laser (VECSEL), etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). The term LED may also refer to a plurality of LEDs. The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2- 2000 solid state light sources. Hence, herein (in embodiments) the term “solid state light source” and “light source” may essentially be equivalent.

[0055] In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs. Hence, in embodiments, the light generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device may comprise a laser device, like a laser diode. In embodiments, the light generating device may comprise a superluminescent diode. Hence, in specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED.

[0056] The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin.

[0057] The term “solid state light source”, or “solid state material light source”, and similar terms (like “light source”), may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, or a superluminescent diode. Hence, the solid state light source and the luminescent arrangement as described herein may provide primary radiation (by the solid state light source) and part of the primary radiation may be converted into secondary radiation (i.e. comprising luminescent material light). Secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be indicated as luminescent material radiation (or luminescent material light). The luminescent material may in embodiments be comprised by a luminescent material layer or dome comprising luminescent material. Embodiments of such combinations may be indicated as phosphor converted LEDs or PC LEDs (phosphor converted LEDs). In other embodiments, the luminescent material may be configured at some distance (“remote”) from the light source, such as an LED with a luminescent material layer not in physical contact with a die of the LED.

[0058] Note that, the light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems.

[0059] In yet a further aspect, the invention also provides a lamp or a luminaire comprising the light generating system as defined herein. The luminaire may further comprise a housing, optical elements, louvres, etc. The lamp or luminaire may further comprise a housing enclosing the light generating system. The lamp or luminaire may comprise a light window in the housing or a housing opening, through which the system light may escape from the housing. In yet a further aspect, the invention also provides a projection device comprising the light generating system as defined herein. Especially, a projection device or “projector” or “image projector” may be an optical device that projects an image (or moving images) onto a surface, such as e.g. a projection screen. The projection device may include one or more light generating systems such as described herein. Hence, in an aspect the invention also provides a lighting device selected from the group of a lamp and a luminaire (or, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device), comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the first light source, the second light source, the first luminescent arrangement and the second luminescent arrangement.

[0060] BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0062] Fig. 1 A-1B schematically depicts embodiments of the light generating system 1000; and

[0063] Fig. 2 schematically depicts embodiments of the lighting device.

[0064] The schematic drawings are not necessarily to scale.

[0065] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0066] Fig. 1 A schematically depicts an embodiment of the light generating system 1000. The figure depicts a cross-section of the light generating system 1000 (top) and an illustration of the first light emitting surface 15 and the second light emitting surface 25 (bottom). In embodiments, the invention provides a light generating system 1000 comprising a first solid state light source 10, a first luminescent arrangement 2100, a second solid state light source 20, and a second luminescent arrangement 2200. In the depicted embodiment, the first solid state light source 10 and the second solid state light source 20 are functionally coupled to the same printed circuit board 50.

[0067] The first light source 10 comprises a first light emitting surface 15 having a first surface area SAi. Especially, the first light source 10 may be configured to generate first light source light 11 which during operation of the first light source 10 emanates from the first light emitting surface 15. In embodiments, the first luminescent arrangement 2100 may be configured in physical contact with at least part of the first light emitting surface 15. Especially, the first luminescent arrangement 2100 may be configured to convert at least part of the first light source light 11 into first luminescent arrangement light 2101. Note that, the first luminescent arrangement 2100 may comprise a first luminescent material 210 configured to convert at least part of the first light source light 11 into first luminescent material light 211. Herein, the first luminescent arrangement light 2101 comprises the first luminescent material light 211. Furthermore, the first light source light 11 may comprise blue light.

[0068] The second light source 20 comprises a second light emitting surface 25 having a second surface area SA2. Especially, the second light source 20 may be configured to generate second light source light 21 which during operation of the second light source 20 emanates from the second light emitting surface 25. In embodiments, the second luminescent arrangement 2200 may be configured in physical contact with at least part of the second light emitting surface 25. Especially, the second luminescent arrangement 2200 may be configured to convert at least part of the second light source light 21 into second luminescent arrangement light 2201. Note that, the second luminescent arrangement 2200 may comprise a second luminescent material 220 configured to convert at least part of the second light source light 21 into second luminescent material light 221. Herein, the second luminescent arrangement light 2201 comprises the second luminescent material light 221. Furthermore, the second light source light 21 may comprise blue light.

[0069] In the depicted embodiment, the first luminescent arrangement 2100 is configured over and in physical contact with the light emitting surface 15. Likewise, the second luminescent arrangement 2200 is configured over and in physical contact with the second light emitting surface 25. Further, the first luminescent arrangement 2100 is configured in a light receiving relationship with the first light source 10, and the second luminescent arrangement 2200 is configured in a light receiving relationship with the second light source 20.

[0070] The first luminescent material 210 may comprise a first manganese-based luminescent material 210a comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese. The second luminescent material 220 may comprise a second manganese-based luminescent material 220a comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese. Herein, M comprises an alkaline earth cation, M’ comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine.

[0071] In embodiments, the first luminescent arrangement 2100 and the second luminescent arrangement 2200 may differ in one or more of (a) volume averaged particle size of the luminescent material of the type of MxM’2-2xAX6 doped with tetraval ent manganese; (b) manganese dopant concentration of the luminescent material of the type of MXM’2-2XAX6 doped with tetraval ent manganese, and (c) assembly type. The luminescent materials 210,220 may especially comprise tetraval ent manganese. In embodiments, relative to a total molar amount of elements of the type A in the luminescent materials 210,220 0.1- 15% may consist of tetraval ent manganese. Furthermore, the second manganese-based luminescent material 220a may comprise at least 0.2 percent points more manganese than the first manganese-based luminescent material 210a.

[0072] In embodiments, the assembly type may be selected from the group of (i) an encapsulant comprising particulate luminescent material, (ii) a layer comprising particulate luminescent material, and (iii) a ceramic body comprising luminescent material or a glass body comprising luminescent material or a single crystal body comprising luminescent material. Especially, the configuration of the luminescent materials in the respective luminescent arrangements may differ, e.g. the luminescent material may be electrophoretically deposited as thin compact conformal coating or layer versus dispensed as volumetric homogenized dome versus attached via an intermediate silicone layer.

[0073] In the depicted embodiment, the first light emitting surface 15 has a larger area than the second light emitting surface 25, see Fig. 1 A (bottom). Here, the first light emitting surface 15 and the second light emitting surface 25 have a rectangular cross-section. Especially, the first light emitting surface 15 may have a length Li and a width Wi. Analogously, the second light emitting surface 25 may have a length L2 and a width W2. Especially, the first light emitting surface 15 may have one or more dimensions (i.e., Li or Wi) of at least 300 pm. In embodiments, the second light emitting surface 25 has one or more dimensions (i.e., L2 or W2) of at maximum 100 pm. Further, in embodiments, it may apply that SAI / SA2>4, especially SAI / SA2>10.

[0074] In some embodiments, the first light emitting surface 15 may be an epitaxial surface of the first solid state light source 10. Furthermore, the second light emitting surface 25 may be an epitaxial surface of the second solid state light source 20. Hence, many different configurations of the light emitting surfaces may be possible in embodiments.

[0075] It must also be noted that, in some embodiments, a small fraction of at most 5%, such as at most 2%, especially at most 1% of light source light, may escape from the sides of the light source (as opposed to the light emitting surface). Typically, this may be the case for smaller light sources such as a microLED. In such cases, the microLED may be glob-topped or overmolded to (also) cover the sides of the light source. In contrast, the larger light sources may have negligible side emission.

[0076] In further embodiments, the light generating system may comprise a first light generating device 110 and a second light generating device 120. In embodiments, the first light generating device 110 may comprise the first solid state light source 10 and the first luminescent arrangement 2100. Likewise, in embodiments, the second light generating device 120 may comprise the second solid state light source 20 and the second luminescent arrangement 2200. In the depicted embodiments, the first light generating device 110 is configured to generate first device light 111 and the second light generating device 120 is configured to generate second device light 121. The first device light 111 may be white light. Analogously, the second device light 121 may be white light. In further embodiments, the first device light 111 and the second device light 121 may have a correlated color temperature difference of at least 500 K. Therefore, in embodiments, the light generating system 1000 may be configured to generate system light 1001 comprising (a) one or more of the first luminescent arrangement light 2101 and the second luminescent arrangement light 2201, and optionally (b) one or more of the first light source light 11 and the second light source light 21.

[0077] Furthermore, in embodiments, the light generating system 1000 may comprise a control system 300. The control system 300 is configured to individually control the first light source 10 and the second light source 20. Especially, the control system 300 may be configured to control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer.

[0078] Fig. IB schematically depicts a cross-section of further embodiments of the light generating system 1000. For the sake of illustration several different combinations of light sources 10,20 and luminescent arrangements 2100,2200 are depicted on the same printed circuit board (PCB) 50.

[0079] Configuration I depicts the first light source 10 functionally coupled to the PCB with the first luminescent arrangement 2100 configured over at least a part of the first light emitting surface 15. The height or thickness of the first luminescent arrangement 2100 may vary in embodiments. In the depicted embodiment, the first luminescent arrangement 2100 has a height Hi. Further, the first luminescent arrangement 2100 comprises a first ceramic body or a first glass body or a first single crystal body comprising the first manganese-based luminescent material 210a. Furthermore, in case of a monolithic ceramic luminescent body, the ceramic body may not comprise particles, however, it may yet be possible to distinguish grain boundaries in case of a polycrystalline ceramics.

[0080] Configuration II schematically depicts a second light source 20 functionally coupled to the PCB with the second luminescent arrangement 2200 configured over at least a part of the second light emitting surface 25. Here, the luminescent arrangement may comprise an assembly type of a layer comprising particulate luminescent material. The layer refers to deposition of powder comprising luminescent material 220a, especially a first manganese-based luminescent particles.

[0081] Configuration III has a similar configuration to that of configuration II. However, in contrast, the second luminescent arrangement 2200 comprises an encapsulant comprising particulate luminescent material. The encapsulant may comprise a matrix material wherein luminescent material particles may be embedded.

[0082] Configuration IV depicts the second luminescent arrangement 2200 comprising a second ceramic body or a second glass body or a second single crystal body further comprising the second manganese-based luminescent material 220b. Note that in some embodiments, the first luminescent arrangement 2100 may (also) comprise a second ceramic body or a second glass body or a second single crystal body. However, alternatively, the first luminescent arrangement 2100 may also comprise an assembly type selected from the group of (i) an encapsulant comprising particulate luminescent material, and (ii) a layer comprising particulate luminescent material.

[0083] Configuration V depicts an embodiment wherein the first luminescent arrangement 2100 is configured over at least part of the first light emitting surface 15 of the first light source 10. Herein, the first (manganese-based) luminescent material 220a has a first volume averaged particle size Di. In embodiments, the averaged particle size Di may be at least 5 pm.

[0084] Configuration VI schematically depicts a second light source 20 functionally coupled to the PCB with the second luminescent arrangement 2200 configured over at least a part of the second light emitting surface 25. Here, the luminescent arrangement may comprise an assembly type of a layer comprising particulate luminescent material. Furthermore, the second (manganese-based) luminescent material 220b has a second volume averaged particle size D2. In embodiments, the second luminescent arrangement 2200 may have relatively smaller particulate luminescent material than the first luminescent arrangement 2100. Especially, it may apply that DI / D2>2. In embodiments, the averaged particle size D2 may be at most 1 pm. In specific embodiments, Dl> 5 pm, and D2 < 1 pm. That is, in embodiments, the first volume averaged particle size Di may be (significantly) larger than the second volume averaged particle size D2.

[0085] Configuration VII depicts a configuration wherein the second luminescent arrangement 2200 comprises an encapsulant comprising particulate luminescent material. In embodiments, the second luminescent arrangement 2200 may comprise a second layer thickness H2. Especially, it may apply that H2 / HI<0.9 or H2 / HI>1.1. Fig. 2 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 2 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 2 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001.

[0086] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” also includes embodiments wherein the term “comprises” means “consists of’. The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may in an embodiment refer to "consisting of but may in another embodiment also refer to "containing at least the defined species and optionally one or more other species". Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0087] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

[0088] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0089] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein.

[0090] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

[0091] The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and / or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and / or shown in the attached drawings.

[0092] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined.

[0093] Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A light generating system (1000) comprising a first solid state light source(10), a first luminescent arrangement (2100), a second solid state light source (20), and a second luminescent arrangement (2200), wherein: the first solid state light source (10) comprises a first light emitting surface (15) having a first surface area SAI; wherein the first solid state light source (10) is configured to generate first light source light (11); the first luminescent arrangement (2100) is configured in physical contact with at least part of the first light emitting surface (15); wherein the first luminescent arrangement (2100) is configured to convert at least part of the first light source light (11) into first luminescent arrangement light (2101); wherein the first luminescent arrangement (2100) comprises a first luminescent material (210) configured to convert at least part of the first light source light (11) into first luminescent material light (211); wherein the first luminescent arrangement light (2101) comprises the first luminescent material light (211); the second solid state light source (20) comprises a second light emitting surface (25) having a second surface area SA2; wherein the second solid state light source (20) is configured to generate second light source light (21); the second luminescent arrangement (2200) is configured in physical contact with at least part of the second light emitting surface (25); wherein the second luminescent arrangement (2200) is configured to convert at least part of the second light source light (21) into second luminescent arrangement light (2201); wherein the second luminescent arrangement (2200) comprises a second luminescent material (220) configured to convert at least part of the second light source light (21) into second luminescent material light (221); wherein the second luminescent arrangement light (2201) comprises the second luminescent material light (221); the first luminescent material (210) comprises a first manganese-based luminescent material (210a) comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese; wherein the second luminescent material (220) comprises a second manganese-based luminescent material (220a) comprising a luminescent material of the type MxM’2-2xAXe doped with tetravalent manganese; wherein M comprises an alkalineearth cation, M’ comprises an alkaline cation, x is in the range of 0-1, A comprises a tetravalent cation, and wherein X comprises a monovalent anion, at least comprising fluorine; the first luminescent arrangement (2100) and the second luminescent arrangement (2200) differ in one or more of: (a) volume averaged particle size of the luminescent material of the type of MxM’2-2xAXe doped with tetravalent manganese; (b) manganese dopant concentration of the luminescent material of the type of MxM’2-2xAXe doped with tetravalent manganese, and (c) assembly type; andSA1 / SA2>4, wherein the assembly type is selected from the group of (i) an encapsulant comprising particulate luminescent material, (ii) a layer comprising particulate luminescent material, and (iii) a ceramic body comprising luminescent material or a glass body comprising luminescent material or a single crystal body comprising luminescent material; and wherein the light generating system (1000) is configured to generate system light (1001) comprising (a) one or more of the first luminescent arrangement light (2101) and the second luminescent arrangement light (2201), and optionally (b) one or more of the first light source light (11) and the second light source light (21).

2. The light generating system (1000) according to any one of the preceding claims, wherein the first light emitting surface (15) is an epitaxial surface of the first light source (10), and wherein the second light emitting surface (25) is an epitaxial surface of the second light source (20).

3. The light generating system (1000) according to any one of the preceding claims, wherein the first light emitting surface (15) has one or more dimensions of at least 300 pm, and wherein the second light emitting surface (25) has one or more dimensions of at maximum 100 pm, and wherein SAl / SA2>10.

4. The light generating system (1000) according to any one of the preceding claims, wherein relative to a total molar amount of elements of the type A in the luminescent materials (210,220) 0.1-15% consists of tetravalent manganese, wherein the second manganese-based luminescent material (220a) comprises at least 0.2 percent points more manganese than the first manganese-based luminescent material (210a).

5. The light generating system (1000) according to any one of the preceding claims, wherein the assembly type for both luminescent arrangements (2100,2200) is selected from the group of (i) an encapsulant comprising particulate luminescent material and (ii) a layer comprising particulate luminescent material; wherein the first manganese-based luminescent material (210a) has a first volume averaged particle size DI, wherein the second manganese-based luminescent material (220b) has a second volume averaged particle size D2, wherein Dl / D2>2.

6. The light generating system according to claim 5, wherein Dl> 5 pm, and wherein D2 < 1 pm.

7. The light generating system (1000) according to any one of the preceding claims 1-6, wherein the first luminescent arrangement (2100) comprises a first ceramic body or a first glass body or a first single crystal body comprising the first manganese-based luminescent material (210a), and wherein the second luminescent arrangement (2200) comprises an assembly type selected from the group of (i) an encapsulant comprising particulate luminescent material, and (ii) a layer comprising particulate luminescent material.

8. The light generating system (1000) according to any one of the preceding claims 1-6, wherein the second luminescent arrangement (2200) comprises a second ceramic body or a second glass body or a second single crystal body comprising the second manganese-based luminescent material (220b), and wherein the first luminescent arrangement (2100) comprises an assembly type selected from the group of (i) an encapsulant comprising particulate luminescent material, and (ii) a layer comprising particulate luminescent material.

9. The light generating system (1000) according to any one of the preceding claims, wherein the first luminescent arrangement (2100) comprises a first layer thickness (Hl), and wherein the second luminescent arrangement (2200) comprises a second layer thickness (H2), wherein H2 / Hl<0.7 or H2 / H1>1.3.

10. The light generating system (1000) according to any one of the preceding claims, wherein the first luminescent material (210) and / or the second luminescent material (220) comprise a luminescent material selected from the type AsBsOn Ce3, wherein Acomprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In and Sc.

11. The light generating system (1000) according to any one of the preceding claims, wherein the first light source (10) and the second light source (20) are functionally coupled to a same printed circuit board (50).

12. The light generating system (1000) according to any one of the preceding claims, comprising (i) a first light generating device (110), wherein the first light generating device (110) comprises the first light source (10) and the first luminescent arrangement (2100), and (ii) a second light generating device (120), wherein the second light generating device (120) comprises the second light source (20) and the second luminescent arrangement (2200); wherein the first light generating device (110) is configured to generate first device light (111), wherein the first device light (111) is white light; wherein the second light generating device (120) is configured to generate second device light (121), wherein the second device light (121) is white light; wherein the first device light (111) and the second device light (121) have a correlated color temperature difference of at least 500 K.

13. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a control system (300), wherein the control system (300) is configured to individually control the first solid state light source (10) and the second solid state light source (20); wherein the control system (300) is configured to control in dependence of one or more of an input signal of a user interface, a sensor signal (of a sensor), and a timer.

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

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