High-performance PC-led comprising wavelength converting element

Abstract

The invention provides a light generating system (1000) comprising a first solid state light source (10) and a luminescent converter (2000), wherein: - the first solid state light source (10) is configured to generate first light source light (11) having a first peak wavelength (λp1) selected from a wavelength range of 380 nm to 490 nm; the luminescent converter (2000) is configured in a light receiving relationship with the first solid state light source (10); wherein the luminescent converter (2000) comprises a particulate first luminescent converter material (210) and a particulate second luminescent converter material (220); - the particulate first luminescent converter material (210) comprises a first luminescent material (210a) of the type M'xM2-2 xAX6 doped with tetravalent manganese, wherein M' comprises an alkaline earth cation, M comprises an monovalent cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine; wherein the particulate first luminescent converter material (210) has a first volume averaged particle size P1; the particulate second luminescent converter material (220) comprises a second luminescent material (220a) of the type M'xM2-2xAX6 doped with tetravalent manganese, wherein M' comprises an alkaline earth cation, M comprises an monovalent cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine; wherein the particulate second luminescent converter material (220) has a second volume averaged particle size P2; and - P1 and P2 differ by a factor of at least 2 from each other.

Description

[0001] 2024PF80259

[0002] 1

[0003] HIGH-PERFORMANCE PC-LED COMPRISING WAVELENGTH CONVERTING

[0004] ELEMENT

[0005] FIELD OF THE INVENTION

[0006] The invention relates to a light generating system. The invention further relates to a lighting device comprising said light generating system.

[0007] BACKGROUND OF THE INVENTION

[0008] LED packages with red-emitting phosphors are known in the art. US2015 / 0364659, for instance, describes a process for fabricating a LED lighting apparatus includes disposing a composite coating on a surface of a LED chip. The composite coating comprises a first composite layer having a manganese doped phosphor of formula I and a first binder, and a second composite layer comprising a second phosphor composition and a second binder. The first binder, the second binder or both include a poly(meth)acrylate. Ax[MFy]Mn4+wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; y is 5, 6 or 7.

[0009] SUMMARY OF THE INVENTION

[0010] Conventional light generating systems (e.g. incandescent or fluorescent lamps) are rapidly being replaced by light emitting diode (LED) based lighting solutions. LED-based lighting solutions may generally comprise a light source and a luminescent converter, wherein the luminescent converter may comprise multiple types of phosphors, such as a yellow and a red phosphor, to produce light with a suitable color or color temperature. Prior art systems may make use of narrow-band fluoride red phosphors. However, due to their intrinsic hygroscopic nature, these phosphors may degrade over time due to contact with moisture, thereby reducing the lifetime of the light generating system and / or causing a change in optical properties of the system light over time. Further, known LED-based lighting solutions may suffer from low lumen per Watt efficiency, which may increase energy consumption by consumers. Yet further, prior art solutions may have problems with self-absorption in the phosphor layer, wherein light emitted by a first type of phosphor is 2024PF80259

[0011] 2 absorbed by a second type of phosphor, thereby reducing the efficiency of the system and altering one or more of the correlated color temperature (CCT), color rendering index (CRI), and color point of the system light. As such, there appears to be a desire for light generating systems that may especially be efficient and have stable (moisture-resistant) spectral properties. Especially, it may be desired to provide a light generating system based on narrow-band fluoride red phosphors with high luminous efficiency, high color quality, and improved stability of the phosphor. Further, there appears to be a desire for alternative red emitting solid state light sources. 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.

[0012] According to a first aspect, the invention provides a light generating system comprising a first solid state light source and a luminescent converter. In embodiments, the first solid state light source is configured to generate first light source light having a first peak wavelength (Apt) selected from a wavelength range of 380 nm to 490 nm. Especially, the luminescent converter may be configured in a light receiving relationship with the first solid state light source. In embodiments, the luminescent converter may comprise a particulate first luminescent converter material (“first luminescent material”) and a particulate second luminescent converter material (“second luminescent material”). Especially, in embodiments the particulate first luminescent converter material may comprise a first luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ may comprise an alkaline earth cation, M may comprise an monovalent cation (especially wherein M may comprise an alkaline cation), and x is in the range of 0-1, wherein A may comprise a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X may comprise a monovalent anion, at least comprising fluorine. Further, especially the particulate first luminescent converter material may have a first volume averaged particle size Pl. Especially, the particulate first luminescent converter material may be configured to convert at least part of the first light source light received by the particulate first luminescent converter material into first luminescent converter material light (“first luminescent material light”). In embodiments, the first luminescent material light may have a first centroid wavelength ( ci) selected from the range of 610-650 nm. Further, in embodiments the first luminescent material light may comprise at least one emission band having a first full width at half maximum FWHMi of < 40 nm. Yet, in embodiments the particulate second 2024PF80259

[0013] 3 luminescent converter material may comprise a second luminescent material of the type M’XM2-2XAX6 doped with tetravalent manganese, wherein M’ may comprise an alkaline earth cation, M may comprise an monovalent cation (especially wherein M may comprise an alkaline cation), and x is in the range of 0-1, wherein A may comprise a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X may comprise a monovalent anion, at least comprising fluorine. Further, the particulate second luminescent converter material may have a second volume averaged particle size P2. Especially, the particulate second luminescent converter material may be configured to convert at least part of the first light source light received by the particulate second luminescent converter material into second luminescent converter material light (“second luminescent material light”). In embodiments, the second luminescent material light may have a second centroid wavelength ( C2) selected from the range of 610-650 nm. Further, in embodiments the second luminescent material light may comprise at least one emission band having a second full width at half maximum FWHM2 of < 40 nm. Especially, in embodiments the light generating system may be configured to generate, in an operational mode of the light generating system, system light having spectral power in an orange-red wavelength range comprising the first luminescent converter material light and the second luminescent converter material light. Especially, in embodiments Pl and P2 may differ, such as in specific embodiments by a factor of at least 2, from each other. Hence, in embodiments the invention provides a light generating system comprising a first solid state light source and a luminescent converter, wherein: (A) the first solid state light source is configured to generate first light source light having a first peak wavelength (Apt ) selected from a wavelength range of 380 nm to 490 nm; the luminescent converter is configured in a light receiving relationship with the first solid state light source; wherein the luminescent converter comprises a particulate first luminescent converter material and a particulate second luminescent converter material; (B) the particulate first luminescent converter material comprises a first luminescent material of the type M’XM2-2XAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation, especially wherein M comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine; wherein the particulate first luminescent converter material has a first volume averaged particle size Pl; wherein the particulate first luminescent converter material is configured to convert at least part of the first light source light received by the particulate first luminescent converter material into first luminescent converter material light; 2024PF80259

[0014] 4 wherein the first luminescent material light has a first centroid wavelength ( ci) selected from the range of 610-650 nm; wherein the first luminescent material light comprises at least one emission band having a first full width at half maximum FWHMi of < 40 nm; (C) the particulate second luminescent converter material comprises a second luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation (especially wherein M comprises an alkaline cation), and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine; wherein the particulate second luminescent converter material has a second volume averaged particle size P2; wherein the particulate second luminescent converter material is configured to convert at least part of the first light source light received by the particulate second luminescent converter material into second luminescent converter material light; wherein the second luminescent material light has a second centroid wavelength ( C2) selected from the range of 610-650 nm; wherein the second luminescent material light comprises at least one emission band having a second full width at half maximum FWHM2 of < 40 nm; (D) the light generating system is configured to generate system light having spectral power in an orange-red wavelength range comprising the first luminescent converter material light and the second luminescent converter material light; and (E) Pl and P2 differ by a factor of at least 2 from each other.

[0015] With such alternative light generating systems and lighting devices may be provided, that may be optimized in terms of conversion, stability, and absorption characteristics. Hence, the light generating system may provide (a compromise of) relatively high quality light together with improved stability of the phosphor (and thus the system).

[0016] As indicated above, the light generating system may comprise a first solid state light source and a luminescent converter. Here below, embodiments of the different elements of the light generating system will be described in further detail.

[0017] In embodiments, the light generating system may comprise a solid state light source. The solid state light source may be any solid state light source known in the art (see below). Especially, the solid state light source may be a (single) light emitting diode (LED). Alternatively, the solid state light source may be selected from the group of a laser diode, a superluminescent diode, and a multi -junction light emitting diode. In embodiments, the solid state light source may especially comprise one or more light emitting diodes. Especially, in embodiments, the solid state light source may comprise a plurality of light emitting diodes. Hence, in specific embodiments, the solid state light source may be selected from the group 2024PF80259

[0018] 5 of a light emitting diode, a laser diode, a superluminescent diode, and a multi -junction light emitting diode. Such a solid state light source may be relatively small. Further, such a solid state light source may be relatively energy-efficient and / or provide relatively high-intensity light.

[0019] The solid state light source may be configured to generate light source light. The light source light may have a peak emission wavelength (Xp) selected from the range of 380-490 nm, such as from the range of 400-490 nm, especially from the range of 420-490 nm, like from the range of 430-490 nm. Hence, the light source light may be violet light or blue light. The term “violet light”, and similar terms, may especially relate to light having a wavelength in the range of about 380-440 nm. The term “blue light”, and similar terms, may especially relate to light having a wavelength in the range of about 440-490 nm. The term “peak wavelength” may refer to the wavelength where the radiometric emission spectrum of the light source reaches its maximum, i.e., the peak wavelength may denote the wavelength at which the largest (emission intensity) value is found in a graph of the spectral power distribution. The peak wavelength may especially be determined at room temperature.

[0020] The light generating system may further comprise a luminescent converter. In embodiments, the luminescent converter may be configured as a coating covering the solid state light source. Alternatively, the luminescent converter may be configured as a (self- supporting) luminescent body. In such embodiments, the luminescent converter may be configured in physical contact with (at least part of) the solid state light source. Alternatively, in such embodiments, the luminescent converter may be configured physically separated from the solid state light source. In embodiments, the luminescent converter may be configured in a light receiving relationship with the solid state light source. Hence, the luminescent converter may be configured downstream from the solid state light source.

[0021] The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here especially the solid state light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”. Hence, in specific embodiments, the luminescent converter may be configured downstream from the solid state light source. Especially, in embodiments, the luminescent converter may be configured in physical contact with the solid state light source. 2024PF80259

[0022] 6

[0023] In embodiments, the luminescent converter comprises a particulate first luminescent converter material and a particulate second luminescent converter material. Furthermore, in embodiments, the luminescent converter may comprise a matrix material (see also further below). The particulate first luminescent converter material may especially be configured embedded in the matrix material. Similarly, the particulate second luminescent converter material may especially be configured embedded in the matrix material. Such a configuration may provide a homogeneous distribution of the particulate first luminescent converter material and particulate second luminescent converter material in the main matrix material, and therefore a homogeneous distribution of the first and second luminescent material. Further, the present solution may provide a relatively stable solution.

[0024] In embodiments, the first luminescent material may be configured to convert at least part of the light source light received by the first luminescent material into first luminescent material light. Especially, the first luminescent material may be configured to convert > 50%, such as > 60%, especially > 70%, of (a spectral power of) the light source light received by the first luminescent material into first luminescent material light. Further, the first luminescent material may be configured to convert > 80%, such as > 90%, especially > 95%, like > 98%, including (essentially) 100%, of (a spectral power of) the light source light received by the first luminescent material into first luminescent material light.

[0025] The first luminescent material light may have a first centroid wavelength (Xci). In embodiments, the first centroid wavelength (Xci) may be selected from the range of 600- 660 nm, like from the range of 610-650 nm, such as from the range of 610-640 nm.

[0026] The term “centroid wavelength”, also indicated as Ac, is known in the art, and refers to the wavelength value (in nm) where half of the light energy is at shorter and half the energy is at longer wavelengths. It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula Ac = X I(k) / (S I( X)), where the summation is over the wavelength range of interest, and 1(A) is the spectral energy density (i.e. the integration of the product of the wavelength and the intensity over the emission band normalized to the integrated intensity). The centroid wavelength may e.g. be determined at operation conditions.

[0027] The phrase “received by” in e.g. a phrase like “the first luminescent material may be configured to convert at least part of the light source light received by the first luminescent material into first luminescent material light” and other phrases may especially indicate that when the light is actually received by the element, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. 2024PF80259

[0028] 7

[0029] Further, the action may also include refraction. Whether or not such element receives light may e.g. depend on e.g. a controlling mode (for instance whether or not a light generating device provides light). Hence, a phrase like “the luminescent material may be configured to convert > 50% of the light source light received by the luminescent material into luminescent material light”, and similar phrases may thus not necessarily imply that 50% of all the light source light is converted, but that of the light source light received by the luminescent material, at least 50% is converted into luminescent material light. Light source light source light received by the luminescent material but not converted by the luminescent material into luminescent material light may be transmitted, reflected, or converted into thermal energy.

[0030] In embodiments, the second luminescent material may be configured to convert at least part of the light source light received by the second luminescent material into second luminescent material light. Especially, the second luminescent material may be configured to convert > 50%, such as > 60%, especially > 70%, of (a spectral power of) the light source light received by the second luminescent material into second luminescent material light. Further, the second luminescent material may be configured to convert > 80%, such as > 90%, especially > 95%, like > 98%, including (essentially) 100%, of (a spectral power of) the light source light received by the second luminescent material into second luminescent material light.

[0031] The second luminescent material light may have a second centroid wavelength (Xc2). In embodiments, the second centroid wavelength (Ac?) may be selected from the range of 600-660 nm, like from the range of 610-650 nm, such as from the range of 610-640 nm, especially from the range of 625-635 nm. Hence, in embodiments, the second luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light. The first coating layer may especially be at least 80% transmissive for the first luminescent material light, such as at least 90%, like at least 95%.

[0032] Hence, in embodiments, each of the first luminescent material light and the second luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light. The terms “orange light” or “orange emission”, and similar terms, may especially relate to light having a wavelength in the range of about 590- 620 nm. In specific embodiments, the orange light may have a centroid wavelength in the 590-620 nm range. The terms “red light” or “red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 620-780 nm. In specific embodiments, the red light may have a centroid wavelength in the 620-780 nm range, such as in the 620-750 nm range. The phrase “in the orange-red wavelength range”, and similar 2024PF80259

[0033] 8 phrases, may indicate spectral power at one or more wavelengths in the orange wavelength range and / or spectral power at one or more wavelengths in the red wavelength range. The orange-red wavelength range may be defined as the 590-780 nm wavelength range. The terms “orange-red light” or “orange-red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 590-780 nm, more especially in the range of 590-750 nm.

[0034] The term “luminescent material” may refer to a material that can convert first radiation, especially one or more of UV radiation and blue radiation, into second radiation. Herein, UV (ultraviolet) may especially refer to a wavelength selected from the range of 190- 380 nm, such as 200-380 nm, though other wavelengths may also be possible. In general, the first radiation and second radiation have different spectral power distributions, with the second radiation having a spectral power distribution at larger wavelengths than the first radiation (i.e. “down-conversion”). In embodiments, the term “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. The terms “visible light” or “visible emission”, and similar terms, refer to light having one or more wavelengths in the range of about 380-780 nm. Further, infrared (IR) may refer to radiation having a wavelength selected from the range of 780-3000 nm, such as 780-2000 nm, e.g. a wavelength up to about 1500 nm, though in specific embodiments other wavelengths may also be possible.

[0035] For instance, in embodiments the (first and second) luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. Hence, upon excitation with radiation, the luminescent material may emit 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). 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. 2024PF80259

[0036] 9

[0037] In embodiments, the (first and second) luminescent material may comprise a tetravalent manganese-comprising luminescent material, i.e., a luminescent material doped with tetravalent manganese. Especially, in embodiments, the luminescent material may comprise a luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation especially wherein M comprises an alkaline cation, and x may be selected from the range of 0-1, wherein A comprises a tetravalent cation, for instance comprising one or more of silicon and titanium, and wherein X comprises a monovalent anion, at least comprising fluorine. Such luminescent materials may herein also be indicated as “KSiF” or “KSF”, whether or not M comprises K or one or more other (alkaline) cations. A luminescent material of the type M’XM2-2XAX6 doped with tetravalent manganese is amongst others described in WO2013121355A1, which is herein incorporated by reference. Passages from WO2013121355A1 are also copied herein. In embodiments, the alkaline earth cation M’ may comprise one or more of magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. Further, the monovalent cations M may comprise one or more of sodium (Na), potassium (K) and rubidium (Rb). Optionally, M may (further) comprise one or more of ammonium (NFLf), lithium (Li), and cesium (Cs). Hence, in embodiments, M may comprise one or more of K, Rb, Li, Na, Cs, and NHC. In a preferred embodiment, M comprises at least potassium. In yet another embodiment, M comprises at least rubidium. The phrase “wherein M comprises at least potassium” indicates for instance that of all M cations in a mole M’xM2-2xAX6 , a fraction comprises K+and an optionally remaining fraction comprises one or more other monovalent (alkaline) cations (see also below). In another preferred embodiment, M comprises at least potassium and rubidium. Optionally, the M’xM2-2xAX6 luminescent material has the hexagonal phase. In yet another embodiment, the M’xM2-2xAX6 luminescent material has the cubic phase. In an embodiment, a combination of different alkaline cations M may be applied. In yet another embodiment, a combination of different alkaline earth cations M’ may be applied. In yet another embodiment, a combination of one or more alkaline cations M and one or more alkaline earth cations M’ may be applied. For instance, KRbo.sSro^sAXe might be applied. As indicated above, x in the formula M’xM2-2xAX6 may be selected from the range of 0-1, especially x < 1. In specific embodiments, x = 0.

[0038] 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 2024PF80259

[0039] 10 may also be indicated as M’xM2-2xAi-mMnmX6 (or M’xM2-2xAX6:Eu). The mole percentage of manganese, i.e. the percentage it replaces the tetraval ent 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. 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+).

[0040] In embodiments, A may comprise 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 A consists of silicon. In a specific embodiment, M’XM2- 2xAXe 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 in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0- 0.05, and wherein r+l+n+c+nh is in the range of 0-1, especially 1+n+c+nh < 1, especially < 0.2, preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05. X is preferably fluorine (F). Further, 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.

[0041] 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 M2-2xA(Fi-ci-b-iClciBrbIi)6, wherein cl,b,i are each individually preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05, and wherein cl+b+i < 1, especially < 0.2, preferably in the range of 0-0.2, especially in the range of 0-0.1, even more especially in the range of 0-0.05. 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.

[0042] In an embodiment, M’xM2-2xAX6 comprises BGSiFe (indicated herein also as KSiF system). In another preferred embodiment, M’xM2-2xAX6 comprises KRbSiFe (herein also indicated as K,Rb system). In specific embodiments, the indication M’xM2-2xAX6 may 2024PF80259

[0043] 11 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+. As can be derived from the above, “(Si,Ti)” may indicate one or more of Si and Ti. Hence, in specific embodiments, the luminescent material may comprise one or more of (K,Rb)2SiFe:Mn4+and K2(Si,Ti)Fe:Mn4+. The luminescent material may also be coated, as also described in WO2013121355A1.

[0044] Hence, when M’ (or M, or A), etc., in chemical formulas refer to n different elements, this may imply that the relevant formula may comprise for the M’ (or M, or A), etc., position in the formula essentially any permutation of the n different elements. For instance, when M’=Ba,Sr,Ca or when M’ comprises one or more of Ba, Sr, Ca or when M’ refers to Ba,Sr,Ca, this may imply that in the formula Ba, Sr, Ca, (BaxSry), (BaxCay), (CaxSry), or (BaxSryCaz), may be available, wherein in general x+y+z=l. Referring to e.g. M’XM2-2XAX6, this may refer to e.g. one or more of K2SiFe:Mn4+, Rb2SiFe:Mn4+, and (KxRby)2SiFe:Mn4+, etc.. Further, indications like “K,Rb” or “Ba,Sr,Ca”, and similar indications (see also above), may indicate one or more of such elements. Hence, (K,Rb)2SiFe:Mn4+, may e.g. refer to K2SiFe:Mn4+, Rb2SiFe:Mn4+, or (KxRby)2SiFe:Mn4+. Also herein in general x+y=l. Therefore, M may comprise one or more of K, Rb, Li, Na, Cs, and NH4+. Likewise, K2(Si,Ti)Fe:Mn4+, may e.g. refer to K2SiFe:Mn4+, K2TiFe:Mn4+, or K2(Sia,Tib)Fe:Mn4+. Also herein in general a+b=l. Therefore, in embodiments A may comprise one or more of silicon, titanium, and germanium. Hence, when M’ (or M, or A), etc., may refer to n different elements, with n being at least two, 2n-l permutations may in principle be possible.

[0045] In embodiments, the particulate first luminescent converter material may comprise a first luminescent material of the type M’xM2-2XAXe doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation, especially wherein M comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine.

[0046] The first luminescent material may be configured to convert at least part of the light source light received by the first luminescent material into first luminescent material light. In embodiments, the first luminescent material light may have a first centroid wavelength (Xci), wherein the first centroid wavelength (Xci) may be selected from the range of 590-700 nm, such as from the range of 590-690 nm, especially from the range of 600-670 nm. Further, the first centroid wavelength (Xci) may be selected from the range of 605-660 2024PF80259

[0047] 12 nm, such as from the range of 610-650 nm, especially from the range of 610-640 nm. Hence, in embodiments, the first luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light. The terms “orange light” or “orange emission”, and similar terms, may especially relate to light having a wavelength in the range of about 590-620 nm. The terms “red light” or “red emission”, and similar terms, may especially relate to light having a wavelength in the range of about 620-780 nm.

[0048] Further, in embodiments, the first luminescent material light may comprise at least one emission band having a first full width at half maximum FWHMi of < 50 nm, such as < 40 nm, like < 30 nm, especially <25 nm. In embodiments, the first luminescent material light may comprise a plurality of emission bands, wherein at least one band may have the first full width at half maximum FWHMi. Additionally or alternatively, the first luminescent material light may comprise a plurality of emission bands, wherein essentially all of the emission bands may have the first full width at half maximum FWHMi.

[0049] Hence, in embodiments the particulate first luminescent converter material may be configured to convert at least part of the first light source light received by the particulate first luminescent converter material into first luminescent converter material light. Especially, in embodiments the first luminescent material light may have a first centroid wavelength ( ci) selected from the range of 610-650 nm; wherein the first luminescent material light may comprise at least one emission band having a first full width at half maximum FWHMi of < 40 nm.

[0050] Further, the particulate first luminescent converter material has a first volume averaged particle size Pl (see further below). The particles of the particulate first luminescent converter material may in embodiments be embedded in a matrix material.

[0051] Further, in embodiments the particulate second luminescent converter material may comprise a second luminescent material of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ may comprise an alkaline earth cation, M comprises an monovalent cation, especially wherein M may comprise an alkaline cation, and x is in the range of 0-1, wherein A may comprise a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X may comprise a monovalent anion, at least comprising fluorine (see also above).

[0052] The second luminescent material may be configured to convert at least part of the light source light received by the second luminescent material into second luminescent material light. In embodiments, the second luminescent material light may have a second centroid wavelength (Xc2), wherein the second centroid wavelength (Xc2) may be selected 2024PF80259

[0053] 13 from the range of 590-700 nm, such as from the range of 590-690 nm, especially from the range of 600-670 nm. Further, the second centroid wavelength (Ac?) may be selected from the range of 605-660 nm, such as from the range of 610-650 nm, especially from the range of 610-640 nm. Hence, in embodiments, the second luminescent material light may comprise, such as be, one or more of orange light and red light, such as especially red light.

[0054] Further, in embodiments, the second luminescent material light may comprise at least one emission band having a second full width at half maximum FWHM2 of < 50 nm, such as < 40 nm, like < 30 nm, especially <25 nm. In embodiments, the second luminescent material light may comprise a plurality of emission bands, wherein at least one band may have the second full width at half maximum FWHM2. Additionally or alternatively, the second luminescent material light may comprise a plurality of emission bands, wherein essentially all of the emission bands may have the second full width at half maximum FWHM2.

[0055] Yet, in embodiments the particulate second luminescent converter material may be configured to convert at least part of the first light source light received by the particulate second luminescent converter material into second luminescent converter material light. Especially, in embodiments the second luminescent material light may have a second centroid wavelength ( C2) selected from the range of 610-650 nm; wherein the second luminescent material light may comprise at least one emission band having a second full width at half maximum FWHM2 of < 40 nm.

[0056] As known in the art, luminescent materials of the type M’xM2-2xAX6 doped with tetravalent manganese may have multiple line emissions in the wavelength range of about 610-650 nm, which may each have FWHM of well below 40 nm at room temperature, such as FWHMs of 30 nm or less. This applies to both the first luminescent material as well as the second luminescent material.

[0057] Especially, in embodiments M of the first luminescent material and / or M of the second luminescent material may comprise an alkaline cation.

[0058] Further, the particulate second luminescent converter material may have a second volume averaged particle size P2. The particles of the particulate second luminescent converter material may in embodiments (also) be embedded in a matrix material.

[0059] Especially, in embodiments the light generating system may be configured to generate, in an operational mode of the light generating system, system light having spectral power in an orange-red wavelength range comprising the first luminescent converter material light and the second luminescent converter material light. Hence, in embodiments the system 2024PF80259

[0060] 14 light may have a centroid wavelength selected from the wavelength range of 590-780 nm, more especially from the wavelength range of 590-750 nm, yet even more especially selected from the wavelength range of 590-660 nm. Yet, in embodiments the system light may have a centroid wavelength selected from the wavelength range of 600-660 nm, like from the range of 610-650 nm. Hence, the system light may in embodiments be orange light or red light (or may comprise both orange and red light). Therefore, in embodiments the system light may have spectral power in an orange-red wavelength range, and may in specific embodiments have essentially all its spectral power in the orange-red wavelength range. In embodiments, at least 60%, like at least 70%, such especially at least 80% of the spectral power (of the system light) in the wavelength range of 380-780 nm may be in the 590-780 nm wavelength range. Yet, in embodiments at least 85%, like at least 90%, such especially at least 95% of the spectral power (of the system light) in the wavelength range of 380-780 nm may be in the 590-780 nm wavelength range.

[0061] 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. In embodiments, the light generating system may comprise a control system, configured to e.g. control the first solid state light source. 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” 2024PF80259

[0062] 15 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.

[0063] The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system. Hence, in embodiments the control system may (also) be configured to be controlled by an App on a remote device. In such embodiments the control system of the lighting system may be a slave control system or control in a slave mode. For instance, the lighting system may be identifiable with a code, especially a unique code for the respective lighting system. The control system of the lighting system may be configured to be controlled by an external control system which has access to the lighting system on the basis of knowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the (unique) code. The lighting system may also comprise means for communicating with other systems or devices, such as on the basis of Bluetooth, Thread, WIFI, LiFi, ZigBee, BLE or WiMAX, or another wireless technology. 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, which can only operate in a single operation mode (i.e. “on”, without further tunability). 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.

[0064] Herein, especially embodiments are described wherein the light generating system may have a single operational mode, or single series of operational modes, wherein the system light is orange red system light. Hence, though other embodiments are herein not excluded, essentially only embodiments are herein further described wherein the system light is orange red system light.

[0065] Especially, this may imply that the system light may only comprise a relatively low contribution of the solid state light source light, assuming the latter has spectral power in the visible wavelength range (which is the case when the first light source light is blue light). 2024PF80259

[0066] 16

[0067] For instance, in embodiments the system light may have a spectral power distribution, wherein < 5%, more especially < 2%, of the spectral power in the wavelength range of 380- 780 nm is provided by the first light source light. Further, this may imply that the system light may consist of the first luminescent material light, the second luminescent material light, and optionally further luminescent material light of one or more other luminescent materials that may emit in the orange-red wavelength range. However, the contribution of other luminescent materials may be limited to less than 50%. In specific embodiments, below 50%, more especially up to 40% of the luminescent material volume percentage is provided by an in an orange-red wavelength range emitting luminescent material of a type different from the first luminescent material and the second luminescent material, such as selected from divalent europium comprising nitrides and oxynitrides. Yet in embodiments, less than 50%, more especially at maximum 40% of the spectral power in the 590-750 nm wavelength range may be provided by an in an orange-red wavelength range emitting luminescent material of a type different from the first luminescent material and the second luminescent material. In specific embodiments, at maximum 10% of the spectral power in the 590-750 nm wavelength range may be provided by an in an orange-red wavelength range emitting luminescent material of a type different from the first luminescent material and the second luminescent material. Hence, in embodiments at maximum 10% of the spectral power in the 380-780 nm wavelength range may be provided luminescent material light other than first luminescent converter material light and second luminescent converter material light. Yet, in embodiments at least 90% of the spectral power in the 380-780 nm wavelength range may be provided luminescent material light other than first luminescent converter material light and second luminescent converter material light. The term “in an orange-red wavelength range emitting luminescent material”, and similar terms, may refer to a luminescent material that may provide emission (“luminescence”) (upon excitation with the first light source light) in the orange-red wavelength range.

[0068] Suitable luminescent materials that may emit in the orange-red wavelength range may be selected from nitrides, oxynitrides, sulfides, selenides, and quantum structures, such as quantum dots or quantum rods, etc. Such luminescent materials are known in the art. In embodiments, the luminescent converter may additionally comprise one or more of MS:EU2+and / or IVESisNs Eu2and / or MAlSiNs Eu2and / or Ca2AlSi3O2Ns:Eu2+, etc., wherein M comprises one or more of Ba, Sr and Ca, especially in embodiments at least Sr. Hence, in embodiments, the luminescent material may comprise one or more materials selected from the group consisting of (Ba,Sr,Ca)S:Eu, (Ba,Sr,Ca)AlSiN3:Eu and 2024PF80259

[0069] 17

[0070] (Ba,Sr,Ca)2SisN8:Eu. In these compounds, europium (Eu) is substantially or only divalent, and replaces one or more of the indicated divalent cations, as is known to the person skilled in the art. In general, Eu will not be present in amounts larger than 10% of the cation; its presence will especially be in the range of about 0.5 to 10%, more especially in the range of about 0.5 to 5% relative to the cation(s) it replaces. The term “:Eu”, indicates that part of the metal ions (indicated by M) is replaced by Eu (in these examples by Eu2+). For instance, assuming 2% Eu in CaAlSi Eu, the correct formula could be (Cao.98Euo.o2)AlSiN3.

[0071] At least, however, the luminescent converter comprises the particulate first luminescent converter material and the particulate second luminescent converter material.

[0072] In embodiments, the particulate first luminescent converter material may consist of the first luminescent material, i.e. the first luminescent converter material may consist of particulate first luminescent material. In other embodiments, the particulate first luminescent converter material may consist of coated first luminescent material, i.e. the first luminescent converter material may consist of core-shell type particulate material, wherein the core may essentially consist of the first luminescent material, and the shell comprises a coating. Likewise, in embodiments the particulate second luminescent converter material may consist of the second luminescent material, i.e. the second luminescent converter material may consist of particulate second luminescent material. In other embodiments, the particulate second luminescent converter material may consist of coated second luminescent material, i.e. the second luminescent converter material may consist of core-shell type particulate material, wherein the core may essentially consist of the second luminescent material, and the shell comprises a coating. Coatings of luminescent materials are e.g. described in US2015362150 or US2018230376, which are herein incorporated by reference.

[0073] The particulate first luminescent converter material and the particulate second luminescent converter material may essentially be identical or may (entirely) differ, but may at least differ in their dimensions. Especially, in embodiments Pl and P2 may differ by a factor of at least 1.2, more especially at least 1.5, yet even more especially at least 2 from each other. Hence, the volume averaged particle sizes of the particulate luminescent converter material at least differ. In yet further embodiments, Pl and P2 may differ by a factor of at least 5 from each other. Further, in specific embodiments Pl and P2 may differ by a factor of at maximum 200, such as at maximum 100 from each other.

[0074] In addition to the parameter of volume averaged particle size, one or more of the following features may optionally be different between the particulate first luminescent converter material and the particulate second luminescent converter material, of which some 2024PF80259

[0075] 18 features may be combined: (al) the relative positions of layers comprising the respective particulate luminescent converter materials, relative to the first light source, (bl) the respective volume percentages of the respective particulate luminescent converter materials in such layers, (cl) the respective chemical compositions of the host material (M’xM2-2xAX6) of the respective particulate luminescent converter materials in such layers, (dl) the respective dopant (Mn4+) concentrations of the respective particulate luminescent converter materials in such layers, (el) the thickness of such respective layers, (a2) when a single layer is applied, comprising both particulate luminescent converter materials, possible concentration gradients of the respective particulate luminescent converter materials, (b2) in such single layer, the respective volume percentages of the respective particulate luminescent converter materials, (c2) in such single layer, the respective chemical compositions of the host material (M’xM2-2xAX6) of the respective particulate luminescent converter materials, and (d2) in such single layer the respective dopant (Mn4+) concentrations of the respective particulate luminescent converter materials. Some of these features are herein discussed further below.

[0076] Other features may also be used to control the properties of the luminescent converter, like e.g. coating material(s) (when a coating is applied), coating thickness (when a coating is applied), additives in the layer(s), when two layers are applied, the type of matrix material that may be applied, etc. These features are herein not further discussed in detail.

[0077] In relation to (al) the relative positions of layers comprising the respective particulate luminescent converter materials, relative to the first light source, in embodiments the larger volume averaged particle size particulate luminescent converter material may be configured upstream of the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of stability of the luminescent material. In other embodiments, however, the smaller volume averaged particle size particulate luminescent converter material may be configured upstream of the larger volume averaged particle size particulate luminescent converter material. This may be useful in view of packing of the luminescent material.

[0078] In relation to (bl) the respective volume percentages of the respective particulate luminescent converter materials in such layers, in embodiments the larger volume averaged particle size particulate luminescent converter material may be available in a larger volume percentage than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of stability. In other embodiments, however, the larger volume averaged particle size particulate luminescent converter material may be 2024PF80259

[0079] 19 available in a smaller volume percentage than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of light conversion by the luminescent material. Note that these embodiments may also be combined with a choice of the position of the layer.

[0080] In relation to (cl) the respective chemical compositions of the host material (M’XM2-2XAX6) of the respective particulate luminescent converter materials in such layers, in embodiments the larger volume averaged particle size particulate luminescent converter material may comprise a less stable type of the host material than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of stability. In other embodiments, however, the larger volume averaged particle size particulate luminescent converter material may comprise a higher stable type of the host material than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of light conversion and / or efficiency by the luminescent material, when the less stable luminescent material may be more efficient (and / or have a better absorption. Note that these embodiments may also be combined with a choice of the position of the layer, with especially the less stable luminescent material configured downstream of the more stable luminescent material.

[0081] In relation to (dl) the respective dopant (Mn4+) concentrations of the respective particulate luminescent converter materials in such layers, in embodiments the larger volume averaged particle size particulate luminescent converter material may comprise a higher dopant concentration (luminescent material with higher dopant concentration) than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of stability. In other embodiments, however, the larger volume averaged particle size particulate luminescent converter material may comprise a lower dopant concentration (luminescent material with higher dopant concentration) than the smaller volume averaged particle size particulate luminescent converter material. This may be useful in view of stability, with especially in further embodiments the lower doped material configured upstream of the higher doped material. Hence, also these embodiments may be combined with a choice of the position of the layer.

[0082] In relation to (el) the thickness of such respective layers, in embodiments the larger volume averaged particle size particulate luminescent converter material may be comprised by a thicker layer, whereas the smaller volume averaged particle size particulate luminescent converter material may be comprised by a thinner layer. This may be useful in view of application of the layers. In other embodiments, however, the smaller volume 2024PF80259

[0083] 20 averaged particle size particulate luminescent converter material may be comprised by a thicker layer, whereas the larger volume averaged particle size particulate luminescent converter material may be comprised by a thinner layer. This may be useful in view of tuning of the layer thickness and / or control of conversion. Further, also these embodiments may be combined with a choice of the position of the layer.

[0084] For instance, in embodiments the second layer may provide at least 70% of a total layer height (ht) of the luminescent converter, wherein the total layer height (ht) is defined relative to a light emitting surface of the first light source. In specific embodiments (see further also below), the luminescent converter may (thus) comprise a first layer and a second layer, wherein the second layer is configured downstream of the first layer, wherein the first layer may comprises the particulate first luminescent converter material and wherein the second layer comprises the particulate second luminescent converter material, wherein the particulate first luminescent converter material comprised by the first layer may have a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, and the particulate second luminescent converter material comprised by the second layer, configured downstream of the first layer, may have a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2. In other embodiments, however, the first layer may provide at least 70% of a total layer height (ht) of the luminescent converter. Further variations, however, may also be possible (see elsewhere).

[0085] As indicated above, also a single layer may be provided. In such embodiments, there may be a bimodal particle size distribution, wherein two types of particulate luminescent converter materials, provide respective maxima in the particle size distribution. In such embodiments, the particulate first luminescent converter material may be mixed (e.g. mixed available in the matrix), though there may be concentration gradients. However, there is essentially no complete separation in two layers (see also above). In other embodiments, however, the particulate first luminescent converter material may substantially be homogeneously mixed. Hence, in specific embodiments, the particulate first luminescent converter material and the particulate second luminescent converter material may be configured mixed; and wherein the particulate first luminescent converter material and the particulate second luminescent converter material may provide a bimodal particle size distribution of luminescent material particles of the type M’xM2-2xAX6 doped with tetravalent manganese.

[0086] In relation to (a2) when a single layer is applied, comprising both particulate luminescent converter materials, possible concentration gradients of the respective particulate 2024PF80259

[0087] 21 luminescent converter materials may be available, with in specific embodiments the larger volume averaged particle size particulate luminescent converter material configured closer to the light source than the smaller volume averaged particle size particulate luminescent converter material. Such concentration gradient may be easily obtained, and may be useful in view of efficiency. However, in other specific embodiments the smaller volume averaged particle size particulate luminescent converter material may be configured closer to the light source than the larger volume averaged particle size particulate luminescent converter material. Such concentration gradient may allow a higher packing of the layer. See further also above.

[0088] In relation to (b2) in such single layer, the respective volume percentages of the respective particulate luminescent converter materials may be selected, e.g. to optimize packing. In specific embodiments the larger volume averaged particle size particulate luminescent converter material may be available in a higher volume percentage than the smaller volume averaged particle size particulate luminescent converter material. In other embodiments, however, the smaller volume averaged particle size particulate luminescent converter material may be available in a higher volume percentage than the larger volume averaged particle size particulate luminescent converter material (see further also above).

[0089] Hence, e.g. in embodiments a particulate luminescent converter material, selected from the particulate first luminescent converter material and the particulate second luminescent converter material, having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, provides at least 70 vol.% of a total volume defined by the particulate first luminescent converter material and the particulate second luminescent converter material. Hence, the volume percentage of the particulate luminescent converter material having in average the larger particles may be larger than the volume percentage of the particulate luminescent converter material having in average the smaller particles. However, in other embodiments, this may be other way around.

[0090] In relation to (c2) in such single layer, the respective chemical compositions of the host material (M’xM2-2xAX6) of the respective particulate luminescent converter materials may be selected, e.g. to obtain the desired absorption and / or spectral properties and / or comprise between stability and efficiency. In embodiments the larger volume averaged particle size particulate luminescent converter material may comprise a less stable type of the host material than the smaller volume averaged particle size particulate luminescent converter material, whereas in other embodiments the smaller volume averaged particle size particulate luminescent converter material may comprise a less stable type of the host 2024PF80259

[0091] 22 material than the larger volume averaged particle size particulate luminescent converter material (see further also above).

[0092] In relation to (d2) in such single layer the respective dopant (Mn4+) concentrations of the respective particulate luminescent converter materials may be selected, e.g. to obtain the desired absorption and / or spectral properties. In embodiments the larger volume averaged particle size particulate luminescent converter material may comprise a higher dopant concentration (luminescent material with higher dopant concentration) than the smaller volume averaged particle size particulate luminescent converter material, whereas in other embodiments the smaller volume averaged particle size particulate luminescent converter material may comprise a higher dopant concentration (luminescent material with higher dopant concentration) than the larger volume averaged particle size particulate luminescent converter material (see further also above). Hence, in embodiments the particulate luminescent converter material having in average the larger particles may comprise a higher dopant concentration and the particulate luminescent converter material having in average the smaller particles may comprise a lower dopant concentration, whereas in other embodiments the particulate luminescent converter material having in average the larger particles may comprise a smaller dopant concentration and the particulate luminescent converter material having in average the smaller particles may comprise a higher dopant concentration.

[0093] In relation to (al) and (a2), and especially in relation to (al), in embodiments a particulate luminescent converter material, selected from the particulate first luminescent converter material and the particulate second luminescent converter material, having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, is configured closer in distance to the first light source than the particulate luminescent converter material, selected from the particulate first luminescent converter material and the particulate second luminescent converter material, having a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2 (wherein closer in distance is defined along a ray of first light source light).

[0094] Hence, the particulate luminescent converter material having in average the larger particles may be configured upstream of the particulate luminescent converter material having in average the smaller particles. However, in other embodiments, this may be other way around.

[0095] The manganese dopant concentration of the particulate luminescent converter material comprising a higher dopant concentration may be at least 1% or at least 2% higher 2024PF80259

[0096] 23 than the manganese dopant concentration of the particulate luminescent converter material comprising the lower dopant concentration.

[0097] In examples, the first layer may comprise the particulate luminescent converter material comprising a lower dopant concentration and the second layer may comprise the particulate luminescent converter material comprising a higher dopant concentration, wherein the second layer may be configured downstream of the first layer.

[0098] In such examples, the second layer may act as a filter to convert blue light source light leaking through the first layer. A lower Mn4+ dopant concentration may be more efficient due to a decrease in Auger up-conversion losses and the associated temperature rise, particularly at higher light fluxes, thus may also provide the advantage of improved droop behavior, resulting in a first layer with a relatively high conversion efficiency. A higher manganese dopant concentration in the second layer may provide a relatively shorter optical path for light transmitted through the layer and thus, a higher percentage of conversion of light source light to converted light may be achieved. Hence, a higher manganese dopant concentration in the second layer provide for a good conversion efficiency with a more stable color point of the device light.

[0099] The higher manganese dopant concentration may be at least twice as high, especially at least three times as high, such as at least four times as high as the lower manganese dopant concentration.

[0100] The higher manganese dopant concentration may preferably be larger than 3 wt% Mn4+ or larger than 4 wt% Mn4+. The lower manganese dopant concentration may preferably be less than 3 wt% Mn4+ or less than 2 wt% Mn4+.

[0101] Referring again to embodiments with two layers, in embodiments the luminescent converter may (thus) comprise a first layer and a second layer, wherein the second layer is configured downstream of the first layer, wherein the first layer may comprise the particulate first luminescent converter material and wherein the second layer may comprise the particulate second luminescent converter material. In a first line of specific embodiments, the particulate first luminescent converter material comprised by the first layer may have a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, and the particulate second luminescent converter material comprised by the second layer, configured downstream of the first layer, may have a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2. Hence, the particulate luminescent converter material having in average the smaller particles may be configured upstream (relative to the first light source) of the particulate luminescent 2024PF80259

[0102] 24 converter material having in average the larger particles. The second layer comprising the on average larger particles may efficiently protect the first layer comprising the on average smaller particles from environmental influences. Such a luminescent converter may thus have an increased lifetime showing less degradation of the luminescent material, in particular of the luminescent material comprised by the first layer.

[0103] In a second line of specific embodiments, as can also be derived from the above the particulate first luminescent converter material comprised by the first layer may have a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, and the particulate second luminescent converter material comprised by the second layer, configured downstream of the first layer, may have a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2. Hence, the particulate luminescent converter material having in average the larger particles may be configured upstream (relative to the first light source) of the particulate luminescent converter material having in average the smaller particles. Alternatively, one could define that the particulate first luminescent converter material may have a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, and the particulate second luminescent converter material may have a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, the second layer is configured downstream of the first layer, and either the particulate first luminescent converter material is comprised by the first layer and the particulate second luminescent converter material is comprised by the second layer, or the particulate first luminescent converter material is comprised by the second layer and the particulate second luminescent converter material is comprised by the first layer.

[0104] When the particulate first luminescent converter material is comprised by a first layer and the particulate second luminescent converter material is comprised by a second layer, then in general, at least 90 vol% of the first luminescent converter material is comprised by the first layer, such as at least 99%, more especially 100 vol%, and at least 90 vol% of the second luminescent converter material is comprised by the second layer, such as at least 99%, more especially 100 vol%. Likewise, when the particulate first luminescent converter material is comprised by a second layer and the particulate second luminescent converter material is comprised by a first layer, then in general, at least 90 vol% of the first luminescent converter material is comprised by the second layer, such as at least 99%, more especially 100 vol%, and at least 90 vol% of the second luminescent converter material is comprised by the first layer, such as at least 99%, more especially 100 vol%. 2024PF80259

[0105] 25

[0106] In relation to (dl) and (d2), in specific embodiments the first luminescent material may have a first manganese dopant concentration (ml), wherein the second luminescent material may have a second manganese dopant concentration (m2), wherein a particulate luminescent converter material selected from the particulate first luminescent converter material and the particulate second luminescent converter material having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may comprise a lower manganese dopant concentration (selected from the first manganese dopant concentration (ml) and the second manganese dopant concentration (m2)), and wherein a particulate luminescent converter material selected from the particulate first luminescent converter material and the particulate second luminescent converter material, having a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may comprise a higher manganese dopant concentration (selected from the first manganese dopant concentration (ml) and the second manganese dopant concentration (m2)).

[0107] Hence, in embodiments the particulate luminescent converter material having in average the larger particles may comprise a smaller dopant concentration and the particulate luminescent converter material having in average the smaller particles may comprise a higher dopant concentration whereas in other embodiments the particulate luminescent converter material having in average the larger particles may comprise a higher dopant concentration and the particulate luminescent converter material having in average the smaller particles may comprise a lower dopant concentration. Note that in specific embodiments the particulate luminescent converter material having in average the larger particles comprising a smaller dopant concentration may be comprised by the first layer, and the particulate luminescent converter material having in average the smaller particles comprising a higher dopant concentration may be comprised by the second layer (downstream of the first layer). However, this may also be the other way around.

[0108] In above described embodiments, in general the feature of volume averaged particle size is combined with another feature, with in some embodiments also in combination with the feature of the layer position. Note however, that not only binary or ternary combination of features may be possible, but more features may be combined, leading to a substantial number of possible permutations.

[0109] Further, even though the particulate first luminescent converter material and the particulate second luminescent converter material may be comprised by a single layer, it is not excluded that the luminescent converter may comprise further layers ((essentially) not 2024PF80259

[0110] 26 comprising the particulate first luminescent converter material and the particulate second luminescent converter material).

[0111] Yet further, even though the particulate first luminescent converter material and the particulate second luminescent converter material may be comprised by a two different layers, it is not excluded that the luminescent converter may comprise further layers ((essentially) not comprising the particulate first luminescent converter material and the particulate second luminescent converter material), such as e.g. an intermediate layer.

[0112] In specific embodiments, the larger volume averaged particle size may be selected from at least 15 pm, and the smaller volume averaged particle size may be selected from at maximum 5 pm. In yet other embodiments, the larger volume averaged particle size may be selected from at maximum 150 pm, and the smaller volume averaged particle size may be selected from at least 0.1 pm.

[0113] In embodiments, the luminescent converter may comprise a third luminescent material configured to convert at least part of the first light source light received by the third luminescent material into third luminescent converter material light. The third luminescent material light may have a third centroid wavelength Xcs selected from the range of 600-670 nm and may comprise at least one emission band having a first full width at half maximum FWHMi of > 60 nm. The third luminescent material may be selected from the group of divalent europium comprising nitrides and oxynitrides.

[0114] Such a luminescent converter may improve the conversion of the first light source light into system light, such that the system light may only comprise an even lower contribution of the solid state light source light. For instance, in embodiments the system light may have a spectral power distribution, wherein < 2%, especially < 1%, more especially essentially 0% of the spectral power in the wavelength range of 380-780 nm is provided by the first light source light.

[0115] In embodiments, the luminescent converter may comprise a third layer configured downstream of the first layer and the second layer. The third layer may comprise the third luminescent material. Hence, the third layer may act as a protection layer for the first and second layer and the first and second luminescent material.

[0116] Alternatively, in embodiments, the second layer may comprise the particulate second luminescent converter material and the third luminescent material in a mixed configuration. Such a configuration may achieve an improved light conversion of the luminescent converter while keeping the thickness of the luminescent converter as thin as possible. 2024PF80259

[0117] 27

[0118] In embodiments, the luminescent converter may have a luminescent material volume percentage of which at least 60% is provided by the first luminescent material and the second luminescent material, such as at least 70%, like at least 80%. In specific embodiments, the luminescent converter may have a luminescent material volume percentage of which at least 90% is provided by the first luminescent material and the second luminescent material, such as at least about 95%.

[0119] In embodiments, the light generating system (comprising the solid state light source) may be configured to generate system light. The system light may, in embodiments, in an operational mode of the light generating system comprise at least part of the first luminescent material and at least part of the second luminescent material. The system light may have a system centroid wavelength (<cc). In embodiments, the system light may (essentially) consist of at least part of the first luminescent material and at least part of the second luminescent material, and the system centroid wavelength ( cc) may therefore be selected from the range of 600-660 nm, such as from the range of 610-650 nm, especially from the range of 610-640 nm. That is, in embodiments, the system light may comprise, such as be, one or more of orange light and red light, such as especially red light. Furthermore, in embodiments, the system light may have a full width at half maximum FWHMCof <50 nm, such as <40 nm, like <30 nm, especially <25 nm. Such system light may be suitable for darkroom applications. Further, a light generating system configured to generate red system light may function as a red phosphor-converted light source in a lighting device (“PC-LED”).

[0120] Further, in embodiments, the first luminescent material and the second luminescent material may comprise a luminescent material selected from the group comprising: K2SiFe:Mn4+, K2GeFe:Mn4+, and K2TiFe:Mn4+. Especially, in embodiments, the first luminescent material may comprise a luminescent material selected from the group comprising:K2SiFe:Mn4+, K2GeFe:Mn4+, and K2TiFe:Mn4+. More especially, in embodiments, the first luminescent material may comprise K2SiFe:Mn4+. Moreover, in embodiments, the second luminescent material may comprise another luminescent material selected from the group comprising: K2SiFe:Mn4+, K2GeFe:Mn4+, and K2TiFe:Mn4+. Especially, in embodiments, the second luminescent material may comprise one or more of K2GeFe:Mn4+and K2TiFe:Mn4+. However, as described above, in embodiments, the first luminescent material and the second luminescent material may be different. Hence, in specific embodiments, the first luminescent material may comprise a luminescent material selected from the group comprising:K2SiFe:Mn4+, K2GeFe:Mn4+, and K2TiFe:Mn4+, and the second luminescent material may comprise another luminescent material selected from the group 2024PF80259

[0121] 28 comprising: K2SiFe:Mn4+, K2GeFe:Mn4+, and K2TiFe:Mn4+. Especially, in specific embodiments, the first luminescent material may comprise K2SiFe:Mn4+, and the second luminescent material may comprise one or more of K2GeFe:Mn4+and K2TiFe:Mn4+.

[0122] Additionally or alternatively, in embodiments, the first luminescent material and the second luminescent material may differ in x-value. In such embodiments, the x-value may thus individually selected from the range of 0-1 for the first luminescent material and the second luminescent material. For example, in embodiments, for the first luminescent material x may be zero, while for the second luminescent material x may be 1, or vice versa. Yet additionally or alternatively, in embodiments, the first luminescent material and the second luminescent material may differ in relative abundance of the M’ elements. For example, in embodiments, for the first luminescent material may apply that the M’ element may comprise at least 70% (including essentially 100%) Sr, while for the second luminescent material may apply that the M’ element may comprise at least 70% (including essentially 100%) Ba, or vice versa. Similarly, in embodiments, the first luminescent material and the second luminescent material may differ in relative abundance of the M elements. For example, in embodiments, for the first luminescent material may apply that the M element may comprise at least 70% (including essentially 100%) K, while for the second luminescent material may apply that the M element may comprise at least 70% (including essentially 100%) Rb, or vice versa. Yet similarly, in embodiments, the first luminescent material and the second luminescent material may differ in relative abundance of the A elements. For example, in embodiments, for the first luminescent material may apply that the A element may comprise at least 70% (including essentially 100%) Si, while for the second luminescent material may apply that the A element may comprise at least 70% (including essentially 100%) Ti, or vice versa.

[0123] The particulate material may comprise three-dimensional particles having dimensions length Li, width Wi, and height Hi. In embodiments, the length Li may be defined as equal to or larger than the width Wi and larger than height Hi, i.e. the length Li may especially be the largest dimension. Further, in embodiments, the particulate material may have a number averaged equivalent circular diameter Di. 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. The equivalent circular diameter (or ECD) (or 2024PF80259

[0124] 29

[0125] “circular equivalent diameter”) of an (irregularly shaped) two-dimensional shape is the diameter of a circle of equivalent area. For instance, the equivalent circular diameter of a square with side a is 2a / (SQRT(7t)). For a circle, the diameter D is the same as the equivalent circular diameter D. Would a circle in an xy-plane with a diameter D be distorted to any other shape (in the xy-plane), without changing the area size, then the equivalent circular diameter of that shape would be D. In embodiments, the number averaged equivalent circular diameter may be determined by dividing the sum of the equivalent circular diameters of all particulate material particles in the luminescent body by the number of said particulate material particles, i.e. for a luminescent body comprising N particulate material particles, the number averaged equivalent circular diameter may be provided by1 1— .

[0126] 2 Nj

[0127] Herein, particle sizes may be determined with methods known in the art, like one or more of optical microscopy, SEM (scanning electron microscope) and TEM (transmission electron microscopy). Dimensions may be number averaged, as known in the art. Hence, the particles may be substantially identical, but the particles may also mutually differ, such as two or more subsets of particles, wherein within the subsets the particles are substantially identical. The particles may have a unimodal particle size distribution or a polymodal size distribution. From measured dimension, equivalent diameters may be determined.

[0128] As described above, in embodiments, the luminescent converter may (also) comprise a matrix material. The matrix material may especially be a light transmissive, such as light transparent, matrix material. Herein, the term “light transparent” material indicates the material may be transmissive for one or more wavelengths selected from the range of 190-1500 nm, such as for one or more wavelengths selected from the range of 200-1000 nm, especially for one or more wavelengths selected from the range of 380-780 nm (i.e. visible light). Further, in embodiments, the matrix material may be selected from the group comprising glass, polycarbonate (PC), (clear) polyvinyl chloride (PVC), liquid silicone rubber (LSR), cyclic olefin copolymers (COC), fluorinated ethylene propylene (FEP), styrene methyl methacrylate (SMMA), polysiloxanes, and poly(methyl methacrylate) (PMMA). Especially, the matrix material may be selected from the group of crosslinked polysiloxanes. In other words, the matrix material may comprise crosslinked polysiloxane. Examples of suitable (crosslinked) polysiloxanes (from which the first and second matrix material may be individually selected) may be polydimethylsiloxane (PDMS), poly(methyl phenylsiloxane) (PMPS), and polydiphenylsiloxane (PDPS). Hence, in specific embodiments, the matrix 2024PF80259

[0129] 30 material may be selected from the group of crosslinked polysiloxanes. Polysiloxanes may be relatively thermally (and light) stable. Further, the properties of poly siloxanes may be relatively easily adjusted by altering the side groups on the backbone. In specific embodiments, the matrix material may comprise crosslinked PDMS, crosslinked PDPS, crosslinked PMPS, or copolymers thereof. Hence, the matrix material may be a polysiloxane. The term “polysiloxane” refers to a polymer comprising a backbone (or main chain) consisting of alternating silicon (Si) and oxygen (O) atoms, i.e., [-Si— O-]n, wherein [-Si-O-] indicates the repeating unit of the polymer backbone, and n indicates the number of repeating units in the backbone, as is known to the person skilled in the art.

[0130] When the particulate luminescent materials are mixed, they may in embodiments be embedded in the same matrix material. When the respective particulate luminescent materials are configured in different layers, in embodiments the layers may comprise the same matrix materials, and in other embodiments the layer may comprise different matrix materials.

[0131] In embodiments, the luminescent converter may especially be configured in a transmissive mode. Herein, the term “transmissive mode” may indicate that when at least part of the light source light is propagating in the same direction from the luminescent converter as it was propagating to the luminescent converter directly upstream of the luminescent converter, it may have a direction overlapping with the direction in which the luminescent material light escapes from the light generating system. Configuring the luminescent converter in the transmissive mode may facilitate providing the luminescent converter as a coating on the one or more solid-state light sources. Further, configuring the luminescent converter in the transmissive mode may simplify the construction of the light generating system, as no optical elements such as reflectors and / or (dichroic) beam splitters are required to guide the luminescent material light to a light exit of the light generating system.

[0132] The luminescent converter may be a layer, like a self-supporting layer. The luminescent converter may also be a coating. The luminescent converter may have any shape. In general, however, the luminescent converter may comprise two essentially parallel faces, defining a height (of the luminescent converter). Further, the luminescent converter may comprise an edge face, bridging the two essentially parallel faces. The edge face may be curved in one or two dimensions. The edge face may be planar. The luminescent converter may have a rectangular or circular cross-section, though other cross-sections may also be possible, like e.g. hexagonal, octagonal, etc. Hence, the luminescent converter may have a circular cross-section, an oval cross-section, square, or non-square rectangular. The two 2024PF80259

[0133] 31 essentially parallel faces may also be indicated as “main faces”, as they may especially provide the largest external area of the luminescent converter. Hence, in embodiments, the luminescent converter may comprises a first face, a second face, and a side face bridging the first face and the second face. The first face and the second face may also be indicated as main faces. In the case of a cylindrical shape, the side face may be a single side face. In the case of a cuboid, the side face may comprise four facets. In the case of a hexagonal prism the side face may comprise six facets. The luminescent converter may also enclose part of a solid state light source.

[0134] In embodiments, the light generating system may comprise a LED package. The LED package may comprise the solid state light source and the luminescent converter. Optionally, the LED package may further comprise a reflective cup. In such embodiments, the solid state light source and the luminescent converter may be configured in the reflective cup, wherein the solid state light source may be mounted on a base of the reflective cup. The reflective cup may be configured to reflect > 80%, such as > 90%, especially > 95%, including (essentially) 100%, of the (light source and / or luminescent material) light received by the reflective cup. In embodiments, the reflective cup may comprise a reflective coating configured facing one or more of the solid state light source and the fist luminescent converter. Hence, in specific embodiments, the light generating system may comprise a LED package, wherein the LED package may comprise the solid state light source and the luminescent converter. Such a LED package may facilitate providing the solid state light source and the luminescent converter as a single component. Further, such a LED package, especially such a LED package comprising a reflective cup, may facilitate relatively efficiently outcoupling the system light, and may optionally provide beam shaping of a beam of system light.

[0135] Further, in embodiments, the light generating system may comprise a LED filament. The LED filament may especially comprise a plurality of the solid state light sources arranged on a (light transmissive) elongated carrier. Further, in embodiments, the LED filament may comprise an elongated encapsulant comprising (i) the matrix material, (ii) the first particulate material comprising first luminescent material, and (iii) the second particulate material comprising second luminescent material. Hence, especially, the LED filament may comprise an elongated encapsulant comprising the luminescent converter. In embodiments, the elongated encapsulant is configured downstream from the plurality of solid state light sources, wherein the elongated encapsulant is configured in physical contact with and at least partly enclosing the plurality of solid state light sources and at least part of the 2024PF80259

[0136] 32 elongated carrier. Hence, in specific embodiments, the light generating system may comprise a LED filament, wherein the LED filament may comprise (i) a plurality of the solid state light sources arranged on an elongated carrier, and (ii) an elongated encapsulant comprising the luminescent converter. A light generating system comprising a LED filament may better mimic a conventional incandescent light bulb. Below, some general embodiments relating to the LED filament are provided.

[0137] LED filaments as such are known, and are e.g. described in US 8,400,051 B2, W02020016058, WO2019197394, etc., which are herein incorporated by reference. In general, a LED filament may in embodiments comprise (i) a plurality of LEDs, arranged on (at least a first major surface of) an elongated carrier, and (ii) an elongated encapsulant covering the plurality of LEDs and at least part of the elongated carrier. The LED filament may in embodiments be defined by a filament length LF, a filament width WF, and a filament thickness TF. Further, the LED filament may have relatively high aspect ratios (LF / WF or LF / TF), such as 10*WF < LF < 900*WF, and 10*TF < LF < 900*TF. In some embodiments, the LED filament may be straight. In other embodiments, the LED filament may be curved. For instance, the filament may have a (2D or 3D) spiraling shape, (like) a helical shape.

[0138] Further, as indicated, the LED filament may comprise an elongated carrier, solid state light sources, and an encapsulant. Especially, the elongated carrier may support the solid state light sources. The elongated carrier may e.g. comprise glass, quartz, metal, or sapphire. In other embodiments, the elongated carrier may e.g. comprise a polymeric material or (flexible) metal, e.g., a film or foil. The elongated carrier may be rigid (self-supporting), but may (in polymeric embodiments) also be flexible. In embodiments, the elongated carrier may be light transmissive, translucent, or transparent for light, especially visible light. Alternatively, in embodiments, the carrier may be light reflective, such as reflective for one or more of the light source light and the luminescent material light, such as reflective for at least the light source light and the luminescent material light. In specific embodiments, the carrier may be diffuse reflective.

[0139] In embodiments, the (elongated) carrier may comprise a first major surface at a first side of the carrier and a second major surface at a second side of the carrier, opposite to the first side. In embodiments, the solid state light sources may be arranged on at least one of these surfaces. Hence, in embodiments, at least part of, such as all of, the solid state light sources may be mounted onto the first major surface. Additionally or alternatively, at least part of the solid state light sources may be mounted onto the second major surface. Hence, in embodiments, the solid state light sources may be arranged, mounted and / or mechanically 2024PF80259

[0140] 33 coupled on / to the carrier, wherein the carrier may especially be configured to mechanically and / or electrically support the LEDs.

[0141] In embodiments, the solid state light sources may comprise LEDs. Alternatively or additionally, the solid state light sources may comprise diode lasers. Further, the LED filament may comprise one or more of LEDs, laser diodes, superluminescent diodes, and multi -junction light emitting diodes. The (plurality of) solid state light sources may be arranged in an array (on the elongated carrier). The number of solid state light sources in the array may be at least 4, such as at least 8, even more especially at least 12, and may e.g. be up to 100, or yet even larger. Especially, in embodiments the number of solid state light sources in the array may be selected from the range of 10-2000, such as from the range of 10-1500, especially from the range of 10-1000. In embodiments, the solid state light sources may be configured in a ID (linear) array. Further, in embodiments, the solid state light sources may be configured in two ID arrays, one on the first major surface of the elongated carrier and one on the second major surface. A 2D array of solid state light sources of n*m LEDs may also be possible. In embodiments, n may be selected from the range of 1-4, such as 1-3, like 1-2, and m may be selected from the range of larger than n, such as especially selected from the range of at least 4 (when n<4), like at least 6, such as at least 8. Hence, a 2D array of solid state light sources may especially have a (much) smaller number of rows (n) than the number of solid state light sources in those respective rows (m), such as n / m <0.2, like n / m <0.1, especially n / m <0.05.

[0142] In embodiments, the LED filament may comprise an encapsulant. The encapsulant may especially (at least partly) enclose the plurality of solid state light sources. Further, the encapsulant may cover (such as enclose) at least part of the elongated carrier, such as at least (part of) one of the first major and second major surface. In general, the encapsulant may be in contact with the elongated carrier and may enclose all of the solid state light sources. The encapsulant may be a continuous coating along the filament length LF, at one or both of the first and the second major surface. Further, the encapsulant may at least partly enclose the solid state light sources, such as in embodiments > 50% of the total number of solid state light sources in the array, such as > 75%, especially > 95%, up to 100%.

[0143] In embodiments, the encapsulant may comprise a luminescent converter. Alternatively, the luminescent converter may be the encapsulant, i.e., the luminescent converter may be configured as encapsulant. Additionally or alternatively, the encapsulant may comprise a light scattering material, configured embedded in an encapsulant material, e.g. a (flexible) polymer material (such as a silicone). In embodiments, the light scattering 2024PF80259

[0144] 34 material may be configured to scatter (or “diffuse”) the light source light and / or luminescent material light, especially in a direction transverse to a normal of the (first and / or second) major surface. In specific embodiments, the light scattering material may comprise, such as be, the first particulate material. In embodiments, the LED filament may comprise multiple subfilaments.

[0145] In embodiments, the plurality of solid state light sources may be configured on the first major surface of the elongated carrier. In such embodiments, the elongated encapsulant may (also) be configured on the first major surface (and optionally on the second major surface). In yet further embodiments, the elongated encapsulant may be configured on the first major surface, and a second elongated encapsulant may be configured on the second major surface. The second elongated encapsulant may optionally comprise one or more (third) luminescent materials and / or a light scattering material (e.g. BaSCU, A12O3 and TiCL particles).

[0146] Yet further, in embodiments, the light generating system may comprise a Chip-on-Board (CoB). The Chip-on-Board may comprise a plurality of the solid state light sources. As indicated below, the term “CoB” may especially refer to LED chips in the form of a semiconductor chip that is directly mounted onto a substrate. Hence, in embodiments, the CoB may comprise a plurality of the solid state light sources, wherein the solid state light source may especially be an LED. Further, in embodiments, the Chip-on-Board may comprise the luminescent converter (configured as a coating). The luminescent converter may be configured on top of (and in physical contact with) the plurality of solid state light sources. Hence, in specific embodiments, the light generating system may comprise a Chip- on-Board, wherein the Chip-on-Board may comprise (i) a plurality of the solid state light sources, and (ii) the luminescent converter, wherein the luminescent converter may be configured on top of the plurality of solid state light sources. A light generating system comprising a CoB may be relatively compact, as no separate holder is needed for the solid state light sources and / or the luminescent converter. Further, a CoB may be relatively easy to produce.

[0147] Some general embodiments relating to the light source will now be discussed. The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source may comprise a solid state light source (such as a LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 (solid state) (LED) light sources. The phrases “different light sources” or “a plurality of different light sources”, and 2024PF80259

[0148] 35 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. 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 “COB” especially refers to LED chips in the form of a semiconductor chip that is neither encased nor connected but directly mounted onto a substrate, such as a PCB. Hence, a plurality of light emitting semiconductor light sources may be configured on the same substrate. In embodiments, a COB is a multi LED chip configured together as a single lighting module.

[0149] Hence, in embodiments the light generating system may comprises a Chip-on- Board (CoB), wherein the Chip-on-Board (CoB) comprises (i) a plurality of the solid state light sources, and (ii) a luminescent converter, wherein the luminescent converter is configured on top of the plurality of solid state light sources. Further, the luminescent converter may (at least) partially enclose the solid state light sources.

[0150] The term “light source” may also refer to a chip scale package (CSP) and / or a chip scale packaged (CSP) LED. A CSP may comprise a single solid state die (such as a LED) 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. 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, such as especially micro LEDs or “microLEDs” or “pLEDs”. Herein, the term mini size or mini LED especially refers to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm - 1 mm. Herein, the term p size or micro LED especially refers to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of 100 pm and smaller.

[0151] The light source may have a light escape surface. For LEDs it may for instance be the LED die, or when a resin is applied to the LED die, the outer surface of the resin. The term escape surface especially relates to that part of the light source, where the light actually leaves or escapes from the light source. The light source is configured to provide a beam of light. This beam of light (thus) escapes from the light exit surface of the light source. 2024PF80259

[0152] 36

[0153] The term “light source” may refer to a semiconductor light-emitting device, such as an LED, a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser, etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In an embodiment, the light source comprises a LED. The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). Especially, the term “solid state light source” may refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, a superluminescent diode, or a multi -junction light emitting diode.

[0154] In embodiments, the light source may comprise one or more micro-optical elements (array of micro lenses) downstream of a single solid-state light source, or downstream of a plurality of solid-state light sources (i.e. e.g. shared by multiple LEDs). In embodiments, the light source may comprise a LED with on-chip optics. In embodiments, the light source comprises pixelated single LEDs (with or without optics) (offering in embodiments on-chip beam steering). In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) may be indicated as direct color LEDs. In other embodiments, however, the light source may be configured to provide primary radiation and part of the primary radiation is converted into secondary radiation. Secondary radiation may be based on conversion by a luminescent material. The secondary radiation may therefore also be indicated as luminescent material radiation. The luminescent material may in embodiments be comprised by the light source, such as an LED with a luminescent material layer or dome comprising luminescent material. Such LEDs may be indicated as phosphor converted LEDs or PC LEDs. The term “light source” may (thus) refer to a light generating element as such, like e.g. a solid state light source, or e.g. to a package of the light generating element, such as a solid state light source, and one or more of a luminescent material comprising element and (other) optics, like a lens, a collimator. In embodiments, the term “light source” may thus also refer to a combination of a light source, like an LED, and an optical filter, which may change the spectral power distribution of the light generated by the light source. Further, the term “light source” may (thus) in embodiments also refer to a light source that is (also) based on conversion of light, such as a light source in combination with a luminescent converter material. A light converter element (“converter element” or “converter”) may comprise a luminescent material comprising element. For instance, a solid state light source as such, like a blue LED, is a light 2024PF80259

[0155] 37 source. A combination of a solid state light source (as light generating element) and a light converter element, such as a blue LED and a light converter element, optically coupled to the solid state light source, may also be a light source.

[0156] 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 or multi -junction (light emitting) diode. The light source may especially be configured to generate light source light having an optical axis (O), (a beam shape,) and a spectral power distribution. The light source light may in embodiments comprise one or more bands, having band widths as known for lasers

[0157] The term “laser light source” especially refers to a laser. Such laser may especially be configured to generate laser light source light having one or more wavelengths in the UV, visible, or infrared, especially having a wavelength selected from the spectral wavelength range of 200-2000 nm, such as from the spectral wavelength range of 300-1500 nm. The term “laser” especially refers to a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. Especially, in embodiments the term “laser” may refer to a solid-state laser. In specific embodiments, the terms “laser” or “laser light source”, or similar terms, may refer to a laser diode (or diode laser). Hence, in embodiments the light source comprises a laser light source. In embodiments, the terms “laser” or “solid state laser” or “solid state material laser” may refer to one or more of a semiconductor laser diodes, such as GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt, vertical cavity surface emitting laser (VCSEL), quantum cascade laser, hybrid silicon laser, etc. The term “solid state material laser”, and similar terms, may thus refer to a solid state laser like based on a crystalline or glass body dopes with ions, like transition metal ions and / or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, etc. In embodiments, the term “laser light source” may also refer to a plurality of (different or identical) laser light sources. In specific embodiments, the term “laser light source” may refer to a plurality N of (identical) laser light sources. In embodiments, N>2, such as N>5, especially N>8. In this way, a higher brightness (of the laser light) may be obtained. In embodiments, laser light sources may be arranged in a laser bank. The laser bank may in embodiments comprise heat sinking and / or optics (e.g. a lens to collimate the laser light). Hence, in embodiments lasers in a laser bank (or “laser array bank”) may share the same optics.

[0158] 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 2024PF80259

[0159] 38 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.

[0160] In an aspect, the invention provides a light generating device, wherein the light generating device comprises the first solid state light source and the luminescent converter as (both) described herein.

[0161] 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, a luminaire, a spot light, a stage lighting device, an automotive lighting device, a search lighting device, a projector device, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system as defined herein. Especially, in a second aspect, the invention provides a lighting device selected from the group of a lamp, a luminaire, a projector device, and an automotive headlight, 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.

[0162] The terms “light” and “radiation” are herein interchangeably used, unless clear from the context that the term “light” only refers to visible light. The terms “light” and “radiation” may thus refer to UV radiation, visible light, and IR radiation. In specific 2024PF80259

[0163] 39 embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light.

[0164] BRIEF DESCRIPTION OF THE DRAWINGS

[0165] 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:

[0166] Figs. 1 A-E schematically depict embodiments of the light generating system;

[0167] Figs. 2A-D schematically depict further embodiments an embodiment of a LED filament;

[0168] Fig. 3 shows an excitation and emission spectrum of a KSiF luminescent material; and

[0169] Fig. 4 schematically depict embodiments of the lighting device. The schematic drawings are not necessarily to scale.

[0170] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0171] Referring to Figs. 1 A-1E, and also 2A-2D, the invention provides embodiments of a light generating system 1000 comprising a first solid state light source 10 and a luminescent converter 2000. Furthermore, in embodiments, the first solid state light source 10 may be configured to generate first light source light 11 having a first peak wavelength (kpl) selected from a wavelength range of 380 nm to 490 nm. In embodiments, the luminescent converter 2000 may be configured in a light receiving relationship with the first solid state light source 10. Further, in embodiments, the luminescent converter 2000 may comprise a particulate first luminescent converter material 210 and a particulate second luminescent converter material 220. Moreover, in embodiments, the particulate first luminescent converter material 210 may comprise a first luminescent material (210a) of the type M’XM2-2XAX6 doped with tetravalent manganese. In further embodiments, M’ may comprise an alkaline earth cation, M may comprise an monovalent cation (especially wherein M may comprise an alkaline cation), and x may be in the range of 0-1. Especially, A may comprise a tetravalent cation. The embodiment may comprise one or more of silicon, titanium, and germanium. Furthermore, in embodiments, X may comprise a monovalent anion, at least comprising fluorine. Further, in embodiments, the particulate first luminescent converter material 210 may have a first volume averaged particle size PL Furthermore, in embodiments, the particulate first luminescent converter material 210 may be configured to 2024PF80259

[0172] 40 convert at least part of the first light source light 11 received by the particulate first luminescent converter material 210 into first luminescent converter material light 211. In further embodiments, the first luminescent material light 211 may have a first centroid wavelength ( ci) selected from the range of 610-650 nm. Moreover, in embodiments, the first luminescent material light 211 may comprise at least one emission band having a first full width at half maximum FWHMi of < 40 nm. In further embodiments, the particulate second luminescent converter material 220 may comprise a second luminescent material (220a) of the type M’xM2-2xAX6 doped with tetravalent manganese. Especially, M’ may comprise an alkaline earth cation, M may comprise an monovalent cation (especially wherein M may comprise an alkaline cation), and x may be in the range of 0-1. Furthermore, in embodiments, A may comprise a tetravalent cation. The embodiment may comprise one or more of silicon, titanium, and germanium. In further embodiments, X may comprise a monovalent anion, at least comprising fluorine. Further, in embodiments, the particulate second luminescent converter material 220 may have a second volume averaged particle size P2. Moreover, in embodiments, the particulate second luminescent converter material 220 may be configured to convert at least part of the first light source light 11 received by the particulate second luminescent converter material 220 into second luminescent converter material light 221. In further embodiments, the second luminescent material light 221 may have a second centroid wavelength ( C2) selected from the range of 610-650 nm. Further, in embodiments, the second luminescent material light 221 may comprise at least one emission band having a second full width at half maximum FWHM2 of < 40 nm. In further embodiments, the light generating system 1000 may be configured to generate orange-red system light 1001 comprising the first luminescent converter material light 211 and the second luminescent converter material light 221. Especially, Pl and P2 differ by a factor of at least 2 from each other. Further, in embodiments, the system light 1001 may have a spectral power distribution. Further, in embodiments, < 2% of the spectral power in the wavelength range of 380-780 nm may be provided by the first light source light 11.

[0173] Yet, in embodiments, Pl and P2 differ by a factor of at least 5 from each other. In further embodiments, Pl and P2 differ by a factor of at maximum 100 from each other.

[0174] Figs. 1 A-1D and Fig. 2C may refer to a LED package, indicated with reference 500 refers. Here, the system 1000 may comprise the LED package 500, wherein the LED package 500 comprises the first light generating device 110. The LED package 500 may comprise one or more additional (optical) components. Reference 600 may refer to a reflector cup. Hence, in embodiments the light generating system 1000 may comprise a reflector cup 2024PF80259

[0175] 41

[0176] 700. In further embodiments, the first light source 10 may be at least partly configured in the reflector cup 700. In further embodiments, the luminescent converter 2000 may be configured in the reflector cup 700. The reflector cup 700 may comprise a reflective bottom part 720 and a reflective side part 710.

[0177] Further, in embodiments, the larger volume averaged particle size may be selected from at least 15 pm. Moreover, in embodiments, the smaller volume averaged particle size may be selected from at maximum 5 pm.

[0178] Further, in embodiments, the luminescent converter 2000 may have a luminescent material volume percentage of which at least 60% may be provided by the first luminescent material 210a and the second luminescent material 220a.

[0179] Further, in embodiments, up to 40% of the luminescent material volume percentage may be provided by an in an orange-red wavelength range emitting luminescent material of a type different from the first luminescent material 210a and the second luminescent material 220a (such as selected from divalent europium comprising nitrides and oxynitrides).

[0180] In further embodiments, one or more of the first luminescent material 210a and the second luminescent material 220a may be embedded in a silicone selected from the group of polydimethylsiloxane (PDMS), poly(methyl phenylsiloxane) (PMPS), and polydiphenylsiloxane (PDPS). Reference 250 refers to a matrix material and / or a binder material.

[0181] Referring to e.g. Fig. 1 A, in embodiments a particulate luminescent converter material, selected from the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220, having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may be configured closer in distance to the first light source 10 than the particulate luminescent converter material, selected from the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220, having a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2 (wherein closer in distance may be defined along a ray of first light source light 11).

[0182] Especially, the luminescent converter 2000 may comprise a first layer 2100 and a second layer 2200. Moreover, in embodiments, the second layer 2200 may be configured downstream of the first layer 2100. Especially, the first layer 2100 may comprise the particulate first luminescent converter material 210. Especially, the second layer 2200 may comprise the particulate second luminescent converter material 220. 2024PF80259

[0183] 42

[0184] Especially, as schematically depicted in Fig. 1C, the particulate first luminescent converter material 210 comprised by the first layer 2100 may have a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2. In further embodiments, the particulate second luminescent converter material 220 comprised by the second layer 2200, configured downstream of the first layer 2100, may have a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2. However, this may also be the other way around, see Fig. 1 A.

[0185] Furthermore, in embodiments the second layer 2200 provides at least 70% of a total layer height (ht) of the luminescent converter 2000. Especially, the total layer height (ht) may be defined relative to a light emitting surface 12 of the first light source 10. The layer height of the first layer 2100 is indicated with reference hl and the layer height of the second layer 2200 is indicated with reference h2.

[0186] Referring to Fig. IB, in embodiments, the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220 may be configured mixed. Moreover, in embodiments, the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220 provide a bimodal particle size distribution of luminescent material particles of the type M’xM2-2xAX6 doped with tetravalent manganese.

[0187] In embodiments, a particulate luminescent converter material, selected from the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220, having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may provide at least 70 vol.% of a total volume defined by the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220. This may apply to both the mixed embodiment as well as to the layer embodiment.

[0188] Further, in embodiments the first luminescent material (210a) may have a first manganese dopant concentration (ml). Furthermore, in embodiments, the second luminescent material (220a) may have a second manganese dopant concentration (m2). Especially, a particulate luminescent converter material selected from the particulate first luminescent converter material 210 and the particulate second luminescent converter material 220 having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may comprise a lower manganese dopant concentration. Furthermore, in embodiments, a particulate luminescent converter material selected from the particulate first luminescent converter material 210 and the particulate second luminescent converter material 2024PF80259

[0189] 43

[0190] 220, having a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, may comprise a higher manganese dopant concentration. However, this may also be the other way around.

[0191] Referring to Figs. 1D-1E, in embodiments, the luminescent converter (2000) may comprise a third luminescent material 230,230a configured to convert at least part of the first light source light 11 received by the third luminescent material 230a into third luminescent converter material light 231. Moreover, in embodiments, the third luminescent material light 231 may have a third centroid wavelength Xcs selected from the range of 600- 670 nm and may comprise at least one emission band having a first full width at half maximum FWHMi of > 60 nm. The third luminescent material 230a may be selected from the group of divalent europium comprising nitrides and oxynitrides.

[0192] Referring to Fig. ID, in embodiments, the second layer (2200) may comprise the particulate second luminescent converter material 220 and the third luminescent material 230, 230a in a mixed configuration.

[0193] Referring to Fig. IE, in embodiments, the luminescent converter 2000 may comprise a third layer 2300 configured downstream of the first layer 2100 and the second layer 2200. The third layer 2300 may comprise the third luminescent material 230,230a.

[0194] Referring to Fig. 2A, an embodiment of the light generating system 1000 comprising a LED filament 400 is schematically depicted. Further, the first light generating device 110 may comprise, such as be, the LED filament 400. The LED filament 400 may comprise (i) a plurality of the solid state light sources 10 arranged on a (light-transmissive) elongated carrier 5, and (ii) elongated encapsulants 410,420 comprising the luminescent converter 2000. In embodiments, the upstream configured elongated encapsulant 410 may be configured in physical contact with and covering the plurality of solid state light sources 10 and at least part of the elongated carrier 5. A first elongated encapsulant 410 may comprise the first layer 2100 and a second elongated encapsulant 420 may comprise the second layer 2200. Of course, as the particulate luminescent converter materials 210,220 may be mixed, there may in other embodiments, not depicted in combination with a filament 400, be a single encapsulant comprising both luminescent converter materials 210,220. Hence, the elongated encapsulant 410 (when mixed) or elongated encapsulant 410,420 (when layered luminescent converter) may comprise the luminescent converter 2000.

[0195] Referring to Fig. 2B, in further embodiments, the light generating system 1000 may comprise a Chip-on-Board (CoB) 600. Further, the first light generating device 110 may comprise, such as be, the Chip-on-Board (CoB) 600. In embodiments, the Chip-on-Board 2024PF80259

[0196] 44

[0197] (CoB) 600 may comprise (i) a plurality of the first solid-state light source 10, and (ii) the luminescent converter 2000. Moreover, in embodiments, the first solid state light sources 10 may be configured mounted on a substrate 5, and the luminescent converter 2000 may be configured as a coating. Hence, in embodiments the light generating system 1000 may comprise a Chip-on-Board (CoB) 500. In further embodiments, the Chip-on-Board (CoB) 500 may comprise (i) a plurality of the first solid state light sources 10, and (ii) the luminescent converter 2000. Especially, the luminescent converter 2000 may be configured on top of (and at least partly enclosing) the plurality of first solid state light sources 10.

[0198] Referring to Fig. 2C, a remote configuration has schematically been depicted with a non-zero distance dl between the light sources 10 and the luminescent converter 2000. Reference 13 refers to a light chamber. The light chamber 13 may have reflective wall (reflective for light source light 11, and optionally also for the luminescent material light 211,222).

[0199] Fig. 2D schematically depicts another embodiment of the light generating system 1000 comprising a LED package 500. The LED package 500 may here comprise a first light generating device 110, a second light generating device 120, and a third light generating device 130. The first light generating device 110 may comprise the luminescent converter 2000. Moreover, the first light generating device 110 may comprise the solid-state light source 10. In embodiments, the first light generating device 110 may be configured to generate first device light 111 comprising the first luminescent material light 211 and the second luminescent material light 221. The first device light 111 (of the first light generating device 110) may have a first device centroid wavelength ( ca,i) selected from the range of 610-650 nm. Further, the second light generating device 120 may comprise a secondary solid-state light source 20. The second light generating device 120 may especially be configured to generate second device light 121 having a second device centroid wavelength ( cd,2) selected from the range of 490-590 nm. Further, the third light generating device 130 may comprise a tertiary solid-state light source 30. Additionally, the third light generating device 130 may be configured to generate third device light 131 having a third device centroid wavelength ( ca,3) selected from the range of 380-490 nm.

[0200] In a first operational mode of the light generating system 1000, the light generating system 1000 may be configured to generate system light 1001 comprising the first device light 111, which may thus be orange-red light.

[0201] In a second operational mode of the light generating system 1000, the light generating system 1000 may be configured to generate system light 1001 comprising the first 2024PF80259

[0202] 45 device light 111, the second device light 121, and the third device light 131. Especially, (in the second operational mode,) the system light 1001 may be white light with a CCT selected from the range of 1500-8000 K (and a color rendering index of at least 80). The secondary solid-state light source 20 may be configured to generate secondary light source light 21 having a second peak wavelength (Xp2) selected from the range of 380-490 nm. Further, the second light generating device 120 may comprise a third luminescent converter 2300. The third luminescent converter 2300 may comprise a third luminescent material 230. The third luminescent material 230 may especially be configured to convert at least part of the secondary light source light 21 received by the third luminescent material 230 into third luminescent material light 231. The third luminescent material light 231 may have a third centroid wavelength (A ) selected from the range of 490-590 nm. Further, the second device light 121 may comprise the third luminescent material light 231.

[0203] Hence, the invention also provides embodiments of the light generating system 1000 comprising a LED package 500, which may comprise a plurality of sub-packages. Moreover, in embodiments, the LED package 500 may comprise the first light generating device 110, a second light generating device 120, and a third light generating device 130. Especially, the first device light 111 may have a first device centroid wavelength ( ca,i) selected from the range of 610-650 nm (in the wavelength range of 380-780 nm). In further embodiments, the second light generating device 120 may be configured to generate second device light 121 having a second device centroid wavelength ( ca,2) selected from the range of 490-590 nm. In further embodiments, the third light generating device 130 may be configured to generate third device light 131 having a third device centroid wavelength ( ca,s) selected from the range of 420-490 nm. In further embodiments, in a second operational mode of the light generating system 1000, the light generating system 1000 may be configured to generate white system light 1001 with a CCT selected from the range of 1500- 8000 K (and a color rendering index of at least 80) and comprising the first device light 111, the second device light 121, and the third device light 131. Moreover, in embodiments, the second light generating device 120 may comprise a third luminescent converter 2300. Further, in embodiments, the secondary solid state solid-state light source 20 may be configured to generate secondary light source light 21 having a second peak wavelength (Xp2) selected from the range of 380-490 nm. Especially, the third luminescent converter 2300 may comprise a third luminescent material 230. Especially, the third luminescent material 230 may be configured to convert at least part of the secondary light source light 21 received by the third luminescent material 230 into third luminescent material light 231. Furthermore, in 2024PF80259

[0204] 46 embodiments, the third luminescent material light 231 may have a third centroid wavelength (Acs) selected from the range of 490-590 nm. Moreover, in embodiments, the second device light 121 may comprise the third luminescent material light 231.

[0205] The LED package 500 may further comprise a fourth light generating device 140. The fourth light generating device 140 may comprise a quaternary solid-state light source 40. The quaternary solid-state light source 40 may be configured to generate quaternary light source light 41 having a fourth peak wavelength (Xp4) selected from the range of 380-490 nm. Further, the fourth light generating device 140 may comprise a fourth luminescent converter 2400. The fourth luminescent converter 2400 may comprise a fourth luminescent material 240. The fourth luminescent material 240 may especially be configured to convert at least part of the quaternary light source light 41 received by the fourth luminescent material 240 into fourth luminescent material light 241. The fourth light generating device 140 may be configured to generate fourth device light 141 comprising the fourth luminescent material light 241 and at least part of the quaternary light source light 41. In embodiments, the fourth device light 141 may be white light. For clarity, the first, second, third, and fourth solid-state light sources 10,20,30,40 are indicated with dashed lines in Fig. 3. The light generating system 1000 may comprise a control system 300. The control system 300 may especially be configured to individually control the first light generating device 110, the second light generating device 120, the third light generating device 130, and the fourth light generating device 140.

[0206] Fig. 3 shows an excitation spectrum and emission spectrum of a KSiF luminescent material. Note that excitation spectrum may vary on the type of KSiF luminescent material, whereas the emission spectrum may not vary too much on the type of KSiF luminescent material.

[0207] Fig. 4 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. Fig. 4 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, Fig. 4 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, a photochemical reactor, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In 2024PF80259

[0208] 47 embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001. Reference 1300 refers to a space, such as a room. Reference 1305 refers to a floor and reference 1310 to a ceiling; reference 1307 refers to a wall.

[0209] Fig. 4 also schematically depicts an embodiments of an outdoor light, or stage light, or stadium light. Fig. 4 also schematically depicts a vehicle, like an automobile, but this may also be a truck, a motor cycle, etc. etc., with automotive lighting 4, e.g. headlights. These automotive lighting 4 may also comprise the lighting device 1200.

[0210] 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. 2024PF80259

[0211] 48

[0212] 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.

[0213] 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.

[0214] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0215] 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. 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. 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.

[0216] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

2024PF8025949CLAIMS:

1. A light generating system (1000) comprising a first solid state light source(10) and a luminescent converter (2000), wherein: the first solid state light source (10) is configured to generate first light source light (11) having a first peak wavelength (kpl ) selected from a wavelength range of 380 nm to 490 nm; the luminescent converter (2000) is configured in a light receiving relationship with the first solid state light source (10); wherein the luminescent converter (2000) comprises a first layer (2100) and a second layer (2200), wherein the second layer (2200) is configured downstream of the first layer (2100), wherein the first layer (2100) comprises a particulate first luminescent converter material (210) and wherein the second layer (2200) comprises a particulate second luminescent converter material (220). the particulate first luminescent converter material (210) comprises a first luminescent material (210a) of the type M’xM2-2xAX6 doped with tetraval ent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at least comprising fluorine; wherein the particulate first luminescent converter material (210) has a first volume averaged particle size Pl; wherein the particulate first luminescent converter material (210) is configured to convert at least part of the first light source light (11) received by the particulate first luminescent converter material (210) into first luminescent converter material light (211); wherein the first luminescent material light (211) has a first centroid wavelength ( ci) selected from the range of 610-650 nm; wherein the first luminescent material light (211) comprises at least one emission band having a first full width at half maximum FWHMi of < 40 nm; the particulate second luminescent converter material (220) comprises a second luminescent material (220a) of the type M’xM2-2xAX6 doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, M comprises an monovalent cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, comprising one or more of silicon, titanium, and germanium, wherein X comprises a monovalent anion, at2024PF8025950 least comprising fluorine; wherein the particulate second luminescent converter material (220) has a second volume averaged particle size P2; wherein the particulate second luminescent converter material (220) is configured to convert at least part of the first light source light (11) received by the particulate second luminescent converter material (220) into second luminescent converter material light (221); wherein the second luminescent material light (221) has a second centroid wavelength ( c?) selected from the range of 610-650 nm; wherein the second luminescent material light (221) comprises at least one emission band having a second full width at half maximum FWHM2 of < 40 nm; the light generating system (1000) is configured to generate system light (1001) having spectral power in an orange-red wavelength range comprising the first luminescent converter material light (211) and the second luminescent converter material light (221);Pl and P2 differ by a factor of at least 2 from each other; and the particulate first luminescent converter material (210) comprised by the first layer (2100) has a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, and wherein the particulate second luminescent converter material (220) comprised by the second layer (2200) has a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2.

2. The light generating system (1000) according to claim 1, wherein the system light (1001) has a spectral power distribution, wherein < 2% of the spectral power in the wavelength range of 380-780 nm is provided by the first light source light (11); and wherein at least 80% of the spectral power in the wavelength range of 380-780 nm is in the 590-780 nm wavelength range.

3. The light generating system (1000) according to any one of the preceding claims, wherein Pl and P2 differ by a factor of at least 5 from each other, and wherein Pl and P2 differ by a factor of at maximum 100 from each other; and wherein M of the first luminescent material (210a) and / or M of the second luminescent material (220a) comprises an alkaline cation.

4. The light generating system (1000) according to any one of the preceding claims, wherein the first layer (2100) comprises a first matrix material (250), the particulate first luminescent converter material (210) being configured embedded in the first matrix2024PF8025951 material, and wherein the second layer (2200) comprises a second matrix material (250), the particulate second luminescent converter material (220) being configured embedded in the second matrix material.

5. The light generating system (1000) according to any one of the preceding claims, wherein the second layer (2200) provides at least 70% of a total layer height (ht) of the luminescent converter (2000), wherein the total layer height (ht) is defined relative to a light emitting surface (12) of the first light source (10).

6. The light generating system (1000) according to any one of the preceding claims, wherein the first luminescent material (210a) has a first manganese dopant concentration, wherein the second luminescent material (220a) has a second manganese dopant concentration, wherein a particulate luminescent converter material selected from the particulate first luminescent converter material (210) and the particulate second luminescent converter material (220) having a larger volume averaged particle size, selected from the volume averaged particle sizes P1,P2, comprises a lower manganese dopant concentration, and wherein a particulate luminescent converter material selected from the particulate first luminescent converter material (210) and the particulate second luminescent converter material (220), having a smaller volume averaged particle size, selected from the volume averaged particle sizes P1,P2, comprises a higher manganese dopant concentration.

7. The light generating system (1000) according to any one of the preceding claims, wherein the larger volume averaged particle size is selected from at least 15 pm, and wherein the smaller volume averaged particle size is selected from at maximum 5 pm.

8. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent converter (2000) comprises a third luminescent material (230a) configured to convert at least part of the first light source light (11) received by the third luminescent material (230a) into third luminescent converter material light (231); wherein the third luminescent material light (231) has a third centroid wavelength (Xcs) selected from the range of 600-670 nm; wherein the third luminescent material light (231) comprises at least one emission band having a first full width at half maximum FWHMi of > 60 nm.2024PF80259529. The light generating system (1000) according to claim 8, wherein the third luminescent material (230a) is selected from the group of divalent europium comprising nitrides and oxynitrides.

10. The light generating system (1000) according to claim 8, wherein the luminescent converter (2000) comprises a third layer (2300) configured downstream of the first layer (2100) and the second layer (2200), and wherein the third layer (2300) comprises the third luminescent material (230a).

11. The light generating system (1000) according to claim 8, wherein the second layer (2200) comprises the particulate second luminescent converter material (220) and the third luminescent material (230a) in a mixed configuration.

12. The light generating system (1000) according to any one of the preceding claims, wherein the luminescent converter (2000) has a luminescent material volume percentage of which at least 60% is provided by the first luminescent material (210a) and the second luminescent material (220a).

13. The light generating system (1000) according to claim 12, wherein up to 40% of the luminescent material volume percentage is provided by third luminescent converter material (230) of a type different from the first luminescent material (210a) and the second luminescent material (220a).

14. The light generating system (1000) according to any one of the preceding claims, wherein the light generating system (1000) comprises a Chip-on-Board (CoB) (500), wherein the Chip-on-Board (CoB) (500) comprises (i) a plurality of the first solid state light sources (10), and (ii) the luminescent converter (2000), wherein the luminescent converter (2000) is configured on top of the plurality of first solid state light sources (10); or wherein the light generating system (1000) comprises a LED filament (400), wherein the LED filament (400) comprises (i) a plurality of the first solid state light sources (10) arranged on an elongated carrier (5), and (ii) an elongated encapsulant (410) configured in physical contact with and covering the plurality of first solid state light sources (10) and at least part of the elongated carrier (5); wherein the elongated encapsulant (410) comprises the luminescent converter (2000).2024PF802595315. A lighting device (1200) selected from the group of a lamp (1), a luminaire(2), comprising the light generating system (1000) according to any one of the preceding claims.

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