Lighting device comprising a red de-LED and a KSIF PC-blue LED configured to have overlap of their narrow spectral peaks

Abstract

The invention provides a light generating system, configured to provide system light; wherein the light generating system comprises (i) a first light generating device, (ii) a second light generating device, and (iii) a luminescent material arrangement; wherein: (A) the first light generating device comprises a first solid state light source configured to generate first light source light having a wavelength selected from the wavelength range of 430-490 nm; wherein the first light generating device is configured to generate first device light; (B) the luminescent material arrangement comprises a first luminescent material, configured downstream of the first light source, and configured to convert at least part of the first light source light received by the first luminescent material into first luminescent material light having in the visible wavelength range a first spectral power distribution having a first centroid wavelength (λc1); wherein the first centroid wavelength (λc1) is selected from the wavelength range of 615-645 nm; wherein the first luminescent material light comprises one or more emission bands having first full width half maxima (FWHM1) selected from the range of up to 40 nm; wherein the first luminescent material comprises a luminescent material of the type MxM'2-2xAX6 doped with tetravalent manganese, wherein M comprises an alkaline earth cation, wherein M' comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, wherein X comprises a monovalent anion, at least comprising fluorine; (C) the second light generating device comprises a second solid state light source; wherein the second light generating device is configured to generate second device light having in the visible wavelength range a second spectral power distribution with an emission band having (a) a second centroid wavelength (λc2) selected from the wavelength range of 605-655 nm, and (b) a second full width half maximum (FWHM2) selected from the range of up to 40 nm; and (D) the light generating system is configured such that (a) the first spectral power distribution and the second spectral power distribution at least partly overlap, (b) |λc1-λc2|≤10 nm; and (c) in an operational mode of the light generating system the system light comprises (i) the first luminescent material light and the (ii) second device light.

Description

[0001]2023PF80226 1LIGHTING DEVICE COMPRISING A RED DE-LED AND A KSIF PC-BLUE LEDCONFIGURED TO HAVE OVERLAP OF THEIR NARROW SPECTRAL PEAKS FIELD OF THE INVENTION The invention relates to a light generating system. The invention further relates to a lighting device comprising the light generating system. BACKGROUND OF THE INVENTION Light generating systems are known in the art. For instance, US2017077360 describes a phosphor converted white light emitting device comprising a solid-state light emitter (LED) operable to generate blue light with a dominant wavelength in range 440 nm to 470 nm; yellow to green-emitting phosphor operable to generate light with a peak emission wavelength in a range 500 nm to 550 nm; and a red-emitting manganese-activated fluoride phosphor such a manganese-activated potassium hexafluorosilicate phosphor (K2SiF6:Mn4+). The yellow to green and red-emitting phosphors are incorporated as a mixture and dispersed throughout a light transmissive material with an index or refraction of 1.40 to 1.43. The device can further comprise an orange to red-emitting phosphor operable to generate light with a peak emission wavelength of 580 nm to 620 nm. WO2017 / 021087A1 discloses a lighting device configured to provide lighting device light and comprising a light source configured to provide deep blue radiation in the range of 400-440 nm and blue light in the range of 440-490 nm, a first luminescent material generating yellow / green light, and a second luminescent material generating red light in an emission in the range of 620-680 nm. The lighting device is configured to provide at a first setting of the lighting device white lighting device light comprising deep blue radiation, blue light, first luminescent material light and second luminescent material light. SUMMARY OF THE INVENTION Prior art systems comprising transition-metal-ions Mn4+activated fluoride based phosphors (or luminescent materials) have shown high luminescence efficiency. However, this class of luminescent material may suffer from droop. Droop in phosphors is a phenomenon describing their tendency to lose efficiency as the light flux increases due to excited-state up-conversion losses. Hence, it is desired to provide a light generating system 2023PF80226 2 with less or low droop. Furthermore, such phosphors may exhibit a pump-dependent color shift (e.g. for white LED lighting) due to hydrolysis and light-based damage to the phosphor. Hence, it is desired to provide a light generating system with reduced shift in color point. Additionally or alternatively, it is desired to provide a light generating system with tunable correlated color temperature and / or tunable spectral properties while limiting droop. 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. According to a first aspect, the invention provides a light generating system configured to provide system light. The light generating system may comprise a first light generating device, a second light generating device, and a luminescent material arrangement (or luminescent converter). In embodiments, the first light generating device may comprise a first solid state light source. The first solid state light source may, in embodiments, be configured to generate first light source light. Especially, in embodiments, the first light source light may have a wavelength selected from the wavelength range of 430-490 nm. Hence, in embodiments, the first light source light may be blue light. The luminescent material arrangement may, in embodiments, comprise a first luminescent material configured downstream of the first solid state light source. Especially, the first luminescent material may be configured to convert at least part of the first light source light received by the first luminescent material into first luminescent material light. In embodiments, the first luminescent material light may have in the visible wavelength range a first spectral power distribution having a first centroid wavelength (λc1). Especially, in embodiments, the first centroid wavelength (λc1) may be selected from the wavelength range of 615-645 nm. Moreover, in embodiments, the first luminescent material light may comprise one or more emission bands having (respective) first full width half maxima (FWHM1) selected from the range of up to 40 nm. Furthermore, in embodiments, the first luminescent material may comprise a luminescent material of the type MxM’2-2xAX6doped with tetravalent manganese. Especially, in such embodiments, M comprises an alkaline earth cation, M’ comprises an alkaline cation, and x is in the range of 0-1. Furthermore, in such embodiments, A comprises a tetravalent cation, and X comprises a monovalent anion, at least comprising fluorine. In embodiments, the second light generating device may comprise a second solid state light source. The second solid state light source may be configured to generate second light source light. The second light generating device may, in embodiments, be configured to generate 2023PF80226 3 second device light. Especially, in embodiments, the second device light may have in the visible wavelength range a second spectral power distribution. Especially, in embodiments, the second spectral power distribution may have an emission band having a second centroid wavelength (λc2) selected from the wavelength range of 605-655 nm. Hence, in embodiments, the second device light may be red light. Additionally, in embodiments, the second spectral power distribution may have an emission band having a second full width half maximum (FWHM2) selected from the range of up to 40 nm. Furthermore, in embodiments, the light generating system may be configured such that the first spectral power distribution and the second spectral power distribution at least partly overlap. Additionally, in embodiments, the light generating system may be configured such that |λc1-λc2|≤10 nm. Additionally, in embodiments, the light generating system may be configured such that in an operational mode of the light generating system the system light may comprise (one or more of) (i) the first luminescent material light and (ii) the second device light. Hence, in embodiments, the invention may provide a light generating system configured to provide system light; wherein the light generating system may comprise (i) a first light generating device, (ii) a second light generating device, and (iii) a luminescent material arrangement; wherein: (A) the first light generating device may comprise a first solid state light source configured to generate first light source light having a wavelength selected from the wavelength range of 430-490 nm; wherein the first light generating device is configured to generate first device light; (B) the luminescent material arrangement may comprise a first luminescent material, configured downstream of the first solid state light source, and configured to convert at least part of the first light source light received by the first luminescent material into first luminescent material light having in the visible wavelength range a first spectral power distribution having a first centroid wavelength (λc1); wherein the first centroid wavelength (λc1) may be selected from the wavelength range of 615-645 nm; wherein the first luminescent material light may comprise one or more emission bands having (respective) first full width half maxima (FWHM1) selected from the range of up to 40 nm; wherein the first luminescent material may comprise a luminescent material of the type MxM’2-2xAX6doped with tetravalent manganese, wherein M comprises an alkaline earth cation, wherein M’ comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, wherein X comprises a monovalent anion, at least comprising fluorine; (C) the second light generating device may comprise a second solid state light source; wherein the second light generating device may be configured to generate second device light having in the visible wavelength range a second spectral power distribution with an emission band having (a) a 2023PF80226 4 second centroid wavelength (λc2) selected from the wavelength range of 605-655 nm, and (b) a second full width half maximum (FWHM2) selected from the range of up to 40 nm; and (D) the light generating system may be configured such that (a) the first spectral power distribution and the second spectral power distribution may at least partly overlap, (b) |λc1- λc2|≤10 nm; and (c) in an operational mode of the light generating system the system light may comprise (i) the first luminescent material light and (ii) the second device light. The light generating system may thus combine a red phosphor-converted light source with a (direct-emitting) red light source with overlapping spectral power distributions.The overlap in the spectral power distributions is larger than 50 %, such as larger 60 %,preferably larger than 70 %, more preferably larger than 80 %. Such a light generating system may provide the benefit of using the (direct-emitting) light source for compensating for loss of the phosphor-converted light due to hydrolysis and light-based damage to the phosphor. In this way, an undesired shift in the color point and / or the color rendering index (CRI) of the system light may be reduced. Furthermore, such embodiments may provide a light generating system that can oversaturate red light, which may be desired in e.g., meat lighting. The light generating system may thus comprise a first light generating device, a second light generating device, and a luminescent material arrangement. Here below, embodiments of the light generating devices and the luminescent material arrangement will be described in further detail. The first light generating device may, in embodiments, comprise a first solid state light source. The first solid state light source may, in embodiments, comprise a light source selected from the group comprising a light-emitting diode (LED), a laser diode, a multi-junction light emitting diode, or a superluminescent diode (see also further below). The first solid state light source may, in embodiments, be configured to generate first light source light having a wavelength selected from the wavelength range of 430-490 nm, such as from the range of 440-490 nm, like from the range of 440-470 nm. Especially, in embodiments, the first light source light may have a wavelength in the blue wavelength range. In embodiments, the first light generating device may be configured to generate first device light. In some embodiments, the first device light may comprise part of the first light source light. In embodiments, the first solid state light source may be configured to provide first light source light to the luminescent material arrangement. Therefore, in embodiments, the luminescent material arrangement may be configured downstream of the first solid state light source. In some embodiments, the first luminescent material may (even) be configured 2023PF80226 5 downstream of both the first solid state light source and the second solid state light source. The terms “downstream” and “upstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here especially the 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”. In embodiments, the luminescent material arrangement may comprise a first luminescent material. Especially, the first luminescent material may be configured downstream of the first solid state light source. More especially, in embodiments, the first luminescent material may be provided at a first distance (d1) from the first solid state light source. In some embodiments, the first distance (d1) may be essentially zero, i.e. the first luminescent material may be configured in (direct) physical contact with the first solid state light source. For example, in embodiments, the luminescent material arrangement may comprise a luminescent body or a luminescent layer (see also further below) comprising the first luminescent material and configured in direct contact (such as on top of or over) the first solid state light source. In other embodiments, the first luminescent material may be configured remote from the first solid state light source, i.e., d1≠0. For example, in embodiments, the luminescent material arrangement may comprise a luminescent body or a luminescent layer comprising the first luminescent material and configured remote from the first solid state light source. In such embodiments, the first distance (d1) may be at least 5 µm, such as at least 15 µm, like at least 25 µm. In embodiments, the first distance (d1) may be at most 25 cm, such as at most 15 cm, like at most 5 cm. Hence, in embodiments, the first distance (d1) may be selected form the range of 0-25 cm. In such embodiments, there may (thus) be no physical contact between the first luminescent material and the first solid statelight source. Herein, the first distance may especially be defined as a shortest distancebetween top surface of the first solid state light source and a first surface of the luminescent material arrangement, especially the first luminescent material. The first luminescent material may thus be configured in a light-receiving relationship with the first solid state light source. The phrase “... light received by ...”, and similar phrases, such as “light source light received by the first luminescent material” may especially indicate that when the light is actually received by an item, an action may take place. The action may in embodiments be one or more of conversion, reflection, and transmission. Further, the action may also include refraction. In embodiments, the first luminescent material may be configured to convert at least part of the first light source light 2023PF80226 6 received by the first luminescent material into first luminescent material light. The phrase “to convert at least part of the light source light received by the first luminescent material into first luminescent material light”, and similar phrases, may thus indicate that when at least part of device light indeed irradiates the first luminescent material (in an operational mode of the light generating system), then at least part of that device light may be converted into first luminescent material light. Especially, in embodiments, the first luminescent material may be configured to convert at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the first light source light received by the first luminescent material into first luminescent material light. In some embodiments, the first luminescent material may be configured to convert at least 98%, such as at least 99%, or even 100% of the first light source light received by the first luminescent material into first luminescent material light. In embodiments, the first luminescent material light may have in the visible wavelength range (i.e., the range of 380-780 nm) a first spectral power distribution. The first spectral power distribution may especially have a first centroid wavelength (λc1). The term “centroid wavelength”, also indicated as λc, is known in the art, and refers to the wavelength value where half of the light energy is at shorter and half the energy is at longer wavelengths; the value is stated in nanometers (nm). It is the wavelength that divides the integral of a spectral power distribution into two equal parts as expressed by the formula λc = Σ λ*I(λ) / (Σ I( λ)), where the summation is over the wavelength range of interest, and I(λ) 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. In embodiments, the first centroid wavelength (λc1) may be selected from the wavelength range of 600-780 nm, such as from the wavelength range of 610-750 nm, like from the wavelength range of 610-700 nm, such as from the wavelength range of 615-650 nm, especially from the wavelength range of 615-645 nm. Further, in embodiments, the first centroid wavelength (λc1) may be selected from the wavelength range of 625-635 nm. Furthermore, in embodiments, the first luminescent material light may comprise one or more emission bands having (respective) first full width half maxima (FWHM1). Especially, in embodiments, the first full width half maxima (FWHM1) may be selected from the range of up to 40 nm, especially up to 30 nm, like up to 20 nm. Herein, the full width half maxima may be determined at room temperature (of the (first) luminescent material. That is, the first luminescent material light may have an emission band having a first full width half maximum (FWHM1). The full width half 2023PF80226 7 maximum (FWHM) of an emission band may especially be determined at room temperature. That is, the full width half maximum (FWHM) of an emission band from a luminescent material may be determined when said luminescent material has a temperature selected from the range of 20-25 °C (i.e., room temperature). Further, the full width half maximum (FWHM) of an emission band may be determined from a spectral power distribution of said emission band, and may be defined as the width of the emission band (in nm) at half of the maximum intensity of the emission band. Further, in embodiments, the first luminescent material may comprise a luminescent material of the type M’xM2-2xAX6doped with tetravalent manganese, wherein M’ comprises an alkaline earth cation, 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, wherein X comprises a monovalent anion, at least comprising fluorine. In embodiments, luminescent materials of the type M’xM2-2xAX6 doped with tetravalent manganese 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. Relevant alkaline earth cations (M’) are magnesium (Mg), strontium (Sr), calcium (Ca) and barium (Ba), especially one or more of Sr and Ba. Relevant alkaline cations (M) are sodium (Na), potassium (K) and rubidium (Rb). Optionally, also ammonium (NH4+), lithium (Li) and / or cesium (Cs) may be applied. 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. In an embodiment, preferably at least 80% (i.e.80% of all moles of the type M), even more preferably at least 90%, such as 95% of M consists of potassium and / or rubidium. Optionally, the M’xM2-2xAX6luminescent 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 may be applied. In yet another embodiment, a combination of different alkaline earth cations may be applied. In yet another embodiment, a combination of one or more alkaline cations and one or more alkaline earth cations may be applied. For 2023PF80226 8 instance, KRb0.5Sr0.25AX6might be applied, wherein x may be selected from the range of 0-1, especially x ≤ 1. In specific embodiments, x = 0. 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’xM2-2xAX6doped with tetravalent manganese may also be indicated as M’xM2-2xA1-mMnmX6. The mole percentage of manganese, i.e. the percentage it replaces the tetravalent cation A will in general be in the range of 0.1-15 %, especially 1-12 %, i.e. m is in the range of 0.001-0.15, especially in the range of 0.01-0.12. 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+). In embodiments, A comprises a tetravalent cation, and preferably at least comprises silicon. A may optionally (further) comprise one or more of titanium (Ti), germanium (Ge), stannum (Sn) and zinc (Zn). Preferably, at least 80%, even more preferably at least 90%, such as at least 95% of A consists of silicon. Hence, in a specific embodiment, M’xM2-2xAX6 may also be described as M’xM2-2xA1-m-t-g-s-zrMnmTitGegSnsZrzrX6, wherein m and x are as indicated above, and wherein t,g,s,zr are each individually preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05, wherein t+g+s+zr is smallerthan 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05, and wherein A is especially Si. X is preferably fluorine (F). As indicated above, M relates to monovalent cations, but preferably at least comprises potassium and / or rubidium. Other monovalent cations that may further be comprised by M can be selected from the group consisting of lithium (Li), sodium (Na), cesium (Cs) and ammonium (NH4+). Hence, in a specific embodiment, M’xM2-2xAX6can also be described as (K1-r-l-n-c-nhRbrLilNanCsc(NH4)nh)2AX6, wherein r is in the range of 0-1, wherein l,n,c,nh are each individually preferably in the range of 0-1, preferably 0-0.2, especially 0-0.1, even more especially 0-0.05, and wherein r+ l+n+c+nh is in the range of 0- 1, especially l+n+c+nh is smaller than 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05. X is preferably fluorine (F). As indicated above, instead of or in addition to the alkaline cation(s), also one or more alkaline earth cations may be present. Hence, in a specific embodiment, M’xM2-2xAX6 can also be described as MgmgCacaSrsrBaba(KkRbrLilNanCsc(NH4)nh)2AX6, with k, r, l, n, c, nh each individually being in the range of 0-1, wherein mg, ca, sr, ba are each 2023PF80226 9 individually in the range of 0-1, and wherein mg+ca+sr+ba+k+ r+ l+n+c+nh=1. In embodiments, k=1, and the others (mg, ca, sr, ba, r, l, n, c, nh) are zero. As indicated above, X relates to a monovalent anion, but at least comprises fluorine. Other monovalent anions that may optionally be present may be selected from the group consisting of chlorine (Cl), bromine (Br), and iodine (I). Preferably, at least 80%, even more preferably at least 90%, such as 95% of X consists of fluorine. Hence, in a specific embodiment, M’xM2-2xAX6 can also be described as M’xM2-2xA(F1-cl-b-iClclBrbIi)6, wherein cl,b,i are each individually preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05, and wherein cl+b+i is smaller than 1, especially equal to or smaller than 0.2, preferably in the range of 0-0.2, especially 0-0.1, even more especially 0-0.05. Especially, X may essentially consist of F (fluorine). Hence, M’xM2-2xAX6 can also be described as MgmgCacaSrsrBaba(KkRbrLilNanCsc(NH4)nh)2Si1-m-t-g-s-zrMnmTitGegSnsZrzr(F1-cl-b-iClclBrbIi)6, with k, r, l, n, c, nh each individually being in the range of 0-1, wherein mg, ca, sr, ba are each individually in the range of 0-1, wherein mg+ca+sr+ba+k+ r+ l+n+c+nh=1, and with thevalues for m,t,g,s,zr,cl,b,i as indicated above. X is preferably fluorine (F). In an embodiment,M’xM2-2xAX6 comprises K2SiF6 (indicated herein also as KSiF system). In another preferred embodiment, M’xM2-2xAX6comprises KRbSiF6(herein also indicated as K,Rb system). As indicated above, part of silicon is replaced by manganese (i.e. the formula may also be described as K2Si1-mMnmF6 or KRbSi1-mMnmF6, with m as indicated above, or as KRbSiF6:Mn and K2SiF6:Mn, respectively). Here below, M’xM2-2xAX6is also indicated as M’xM’’2-2xAX6. In specific embodiments, the indication M’xM2-2xAX6may refer to one or more of (K,Rb)2SiF6:Mn4+, (K,Rb)2TiF6:Mn4+, K2(Si,Ti)F6:Mn4+, and Rb2(Si,Ti)F6:Mn4+, such as one or more of K2TiF6:Mn4+, of K2SiF6:Mn4+, and of Rb2SiF6:Mn4+. In embodiments, the tetravalent manganese based narrow-band emitter may comprise (K,Rb)2SiF6:Mn4+. Additionally or alternatively, in embodiments, the tetravalent manganese based narrow-band emitter may comprise K2(Si,Ti)F6:Mn4+. In specific embodiments, the tetravalent manganese based narrow-band emitter may especially comprise K2SiF6:Mn4+. As can be derived from the above, “(Si,Ti)” may indicate one or more of Si and Ti (and “(K,Rb)” may indicate one or more of K and Rb). The (first) luminescent material may also be coated, as also described in WO2013121355A1. Hence, in specific embodiments, the first luminescent material (especially comprising a tetravalent manganese based narrow-band emitter) may comprise one or more of (K,Rb)2SiF6:Mn4+and K2(Si,Ti)F6:Mn4+. Especially, in embodiments, the first luminescent material (i.e., the tetravalent manganese based narrow-band emitter) may 2023PF80226 10 comprise K2SiF6:Mn4+. Such embodiments may be beneficial as so called “KSiF” phosphors show high luminance efficiency and improved performance over other red phosphors such as oxynitrides and nitrides in terms of quantum efficiency, full width half maximum and ideal peak position. Hence, in embodiments, the first luminescent material may comprise a luminescent material of the type M’xM2-2xAX6doped with tetravalent manganese. In embodiments, the luminescent element may also comprise a type of luminescent material different from the first luminescent material, such as e.g. quantum structures, or other types of luminescent materials described further below. However, in embodiments, at least 70 vol.% of the luminescent material in the luminescent element may be of the type M’xM2-2xAX6 doped with tetravalent manganese, such as at least 80 vol.%, like at least 90 vol.%, especially at least 95 vol.%, more especially at least 98 vol.%, including 100 vol.%. As indicated above, the light generating system also comprises a second light generating device. In embodiments, the second light generating device may comprise a second solid state light source configured to generate second light source light. The second light generating device may, in embodiments, be configured to generate second device light having in the visible wavelength range (i.e., 380-780 nm) a second spectral power distribution. The second spectral power distribution may, in embodiments, have an emission band having a second centroid wavelength (λc2). In embodiments, the second centroid wavelength (λc2) may be selected from the wavelength range of 600-780 nm, such as from the wavelength range of 600-750 nm, like from the wavelength range of 605-700 nm, such as from the wavelength range of 605-655 nm, especially from the wavelength range of 610-650 nm. Further, in embodiments, the second centroid wavelength (λc2) may be selected from the wavelength range of 620-640 nm, such as from the wavelength range of 625-635 nm. Especially, in embodiments, the second centroid wavelength (λc2) may be selected from the wavelength range of 617-643 nm. Such embodiments may be beneficial as the second device light may as such overlap with the first luminescent material light in terms of spectral power distribution, therewith allowing for compensation in loss of efficiency in the first luminescentmaterial light by using the second light generating device while reducing or even eliminatinga shift in color point of the system light. Hence, in embodiments, the second light source light may have a spectral power distribution having the second centroid wavelength (λc2) in the red wavelength range. Furthermore, in embodiments, the emission band of the second spectral power distribution may have a second full width half maximum (FWHM2). Especially, in embodiments, the second full width half maximum (FWHM2) may be selected from the range of up to 40 nm, especially up to 30 nm, like up to 20 nm. 2023PF80226 11 The second light generating device, especially the second solid state light source may, in embodiments, comprise a light source selected from the group comprising a light-emitting diode (LED), a laser diode, a multi-junction light emitting diode, or a superluminescent diode (see also further below). In embodiments, the light source may be configured to provide primary radiation, which is used as such, such as e.g. a blue light source, like a blue LED, or a green light source, such as a green LED, and a red light source, such as a red LED. Such LEDs, which may not comprise a luminescent material (“phosphor”) and may be indicated as direct color LEDs. Such a light emitting diode configured to provide primary radiation may also be referred to as “direct-emitting” lightemitting diode. Hence, in embodiments, the second light generating device may comprise adirect-emitting light emitting diode. The direct-emitting light emitting diode (de-LED) may, in embodiments, be configured to emit direct-emitting LED light. In embodiments, the second light generating device may (essentially) be a direct-emitting light emitting diode (de- LED). Hence, in embodiments, the second device light may (essentially) be second light source light. In such embodiments, the second light generating device may especially be free from a luminescent material. Hence, in embodiments, at least 80%, such as at least 90%, especially at least 95%, including 100% of the second device light may comprise the second light source light, especially direct-emitting (red) LED light. In embodiments, at least 80% of the second device light, such as at least 90%, like at least 95%, especially at least 98%, including 100% of the second device light may be direct-emitting LED light. Such embodiments may be beneficial as direct-emitting LED light sources have a relatively low energy consumption and a relatively long lifespan. The light generating system may thus, in embodiments, be configured to generate one or more of first light source light, second light source light, first device light, second device light and first luminescent material light. Especially, in embodiments, the light generating system may be configured to provide system light. As described above, the first light source light may be substantially converted by the first luminescent material into the first luminescent material light. Thus, in embodiments, the light generating system may in an operational mode of the light generating system be configured such that the system light may comprise (one or more of) the second device light (comprising the second light source light) and the first luminescent material light. Additionally, in some embodiments, the light generating system may in an operational mode of the light generating system be configured such that the system light may (still) comprise some (unconverted) first light source light. 2023PF80226 12 Further, in embodiments, the light generating system may be configured such that the first spectral power distribution and the second spectral power distribution may at least partly overlap. In other words, the one or more emission bands of the first luminescent material light having the first full width half maxima (FWHM1) may at least partly overlap with the emission band of the second device light having the second full width half maximum (FWHM2). Especially, in embodiments, the light generating system may be configured such that the first centroid wavelength (λc1) and the second centroid wavelength (λc2) may differ at most 20 nm, especially at most 10 nm. Especially, in embodiments, the light generating system may be configured such that |λc1-λc2|≤15 nm, like |λc1-λc2|≤10 nm, especially |λc1- λc2|≤8 nm. Further, in specific embodiments, |λc1-λc2|≤5 nm, especially |λc1-λc2|≤3 nm. Such embodiments may be beneficial as providing first luminescent material light and second device light with (almost) the same centroid wavelength may allow for compensation in lossof efficiency in the first luminescent material light by using the second light generatingdevice while reducing or even eliminating a shift in color point of the system light. As described above, in embodiments, the system light may thus comprise red second light source light and red first luminescent material light. In embodiments, the light generating system may be configured to (also) provide different colors. Therefore, in embodiments, the light generating system, especially the luminescent material arrangement, may comprise a second luminescent material. The second luminescent material may be configured downstream of the first solid state light source. In some embodiments, the second luminescent material may (even) be configured downstream of both the first solid state light source and the second solid state light source. Hence, in embodiments, the secondluminescent material may be configured in a light-receiving relationship with the first solidstate light source. In particular, in embodiments, the second luminescent material may be configured to convert at least part of the first light source light into second luminescent material light. In embodiments, the second luminescent material may be configured to convert at least 5%, such as at least 15%, especially at least 25% of the first light source light into second luminescent material light. Further, in embodiments, the second luminescent material may be configured to convert at most 98%, such as at most 95%, like at most 90%, especially at most 80% of the first light source light into second luminescent material light. In embodiments, the second luminescent material light may have in the visible wavelength range a (third) spectral power distribution having a third centroid wavelength (λc3). In embodiments, the third centroid wavelength (λc3) may be selected from the wavelength range of 480-600 nm, such as from the wavelength range of 490-590 nm, 2023PF80226 13 especially from the range of 500-590 nm, like from the wavelength range of 500-570 nm. Hence, in embodiments, the third centroid wavelength (λc3) may be selected from the green- yellow wavelength range. In embodiments, the second luminescent material light may thus be green light. In other embodiments, the second luminescent material light may thus be yellow light. Furthermore, in embodiments, the third centroid wavelength (λc3) may also be selected from the range of 590 nm≤λc3<λc2, such as from the range of 600 nm≤λc3<λc2, like from the range of 590 nm≤λc3≤630 and λc3<λc2. Hence, in such embodiments, the second luminescent material light may thus be orange light. Hence, in specific embodiments. the luminescent material arrangement comprises a second luminescent material, wherein the second luminescent material (a) is configured downstream of the first solid state light source and (b) is configured to convert at least part of the first light source light into second luminescent material light having in the visible wavelength range a (third) spectral power distribution having a third centroid wavelength (λc3) selected from the wavelength range of 500-590 nm. Thus, in embodiments, in an operational mode of the light generating system the system light may comprise the first device light and the second device light. In such embodiments, the first device light may comprise one or more of unconverted first light source light, first luminescent material light, and second luminescent material light, especially at least first luminescent material light. Hence, in embodiments, in an operational mode of the light generating system the system light may comprise (one or more of) the first luminescent material light, the second device light, (optionally unconverted first light source light,) and the second luminescent material light. Especially, in embodiments, at least 70%, such as at least 80%, like at least 90%, especially at least 95%, more especially at least 98% of the first device light may be first luminescent material light. Hence, in some embodiments, essentially all of the first device light (i.e., 100%) may be first luminescent material light. However, in other embodiments, the first device light may be a combination of first luminescent material light and second luminescent material light. Note that other contributions of light to the first device light may be possible as well, e.g., the light generating system (especially the luminescent material arrangement) may comprise a third luminescent material (configured to convert at least part of the first light source light into third luminescent material light) such that the first device light may also comprise third luminescent material light. In specific embodiments, at least 90% of the first device light may be first luminescent material light and at least 90% of the second light source light may be direct-emitting LED light. 2023PF80226 14 Additionally or alternatively to the second luminescent material, in embodiments, the light generating system may also comprise a third light generating device. With such an additional light source system light with different colors may be provided, including white system light. The light generating system may especially, in embodiments, comprise the third light generating device. In embodiments, the third light generating device may comprise a third solid state light source configured to generate third light source light. The third light generating device may, in embodiments, be configured to generate third device light having a peak emission wavelength selected from the wavelength range of 430- 490 nm, such as from the range of 440-490 nm, like from the range of 440-470 nm. In embodiments, the third light generating device may be configured to generate third device light having a peak emission wavelength selected from the wavelength range of 435-470 nm. Hence, in embodiments, the third device light may be blue light. The second light generating device, especially the second solid state light source may, in embodiments, comprise a light source selected from the group comprising a light-emitting diode (LED), a laser diode, a multi-junction light emitting diode, or a superluminescent diode (see also further below). Especially, in embodiments, the third light generating device may comprise a direct-emitting light emitting diode. The direct-emitting light emitting diode (de-LED) may, in embodiments, be configured to emit direct-emitting LED light. In embodiments, the third light generating device may essentially be the direct-emitting light emitting diode (de-LED). Hence, in embodiments, the third device light may (essentially) be third light source light. In such embodiments, the second light generating device may especially be free from a luminescent material. Hence, in embodiments, at least 80%, such as at least 90%, especially at least 95%, including 100% of the third device light may comprise the third light source light, especially direct-emitting (blue) LED light. In embodiments, at least 80% of the third device light, such as at least 90%, like at least 95%, especially at least 98%, including 100% of the third device light may be direct-emitting LED light. Hence, in embodiments, the light generating system may comprise a third light generating device configured to provide third device light having apeak emission wavelength selected from the wavelength range of 435-470 nm; wherein thethird light generating device comprises a third solid state light source configured to generate third light source light; and wherein the third light generating device is a direct-emitting light-emitting diode and wherein the third device light is third light source light; and wherein the third device light is blue light. Such embodiments may be beneficial as the addition of the third light generating device may enable tuneability of the spectral properties of the system light such as the spectral power distribution or the color point. Furthermore, the addition of 2023PF80226 15 the third light generating device may enable the generation of white system light with a tunable correlated color temperature using the light generating system. The use of a direct-emitting light-emitting diode may further provide the benefit of relatively low energyconsumption and a relatively long lifespan. Additionally or alternatively to the second luminescent material and / or the third light generating device, in embodiments, the light generating system may also comprise a fourth light generating device. With such an additional light source system light with different colors may be provided, including white system light. The light generating system may especially, in embodiments, comprise the fourth light generating device. The fourth light generating device may, in embodiments, comprise a fourth solid state light source. The fourth solid state light source may, in embodiments, comprise a light source selected from the group comprising a light-emitting diode (LED), a laser diode, a multi-junction light emitting diode, or a superluminescent diode (see also further below). Especially, in embodiments, the fourth light generating device may comprise the fourth light source and a fourth luminescent material, see also further below. In such embodiments, the light source may be configured to provide primary radiation and part of the primary radiation may be converted into secondary radiation. Secondary radiation may be based on conversion by the 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 (phosphor converted LEDs). In other embodiments, the luminescent material may be configured at some distance (“remote”) from the light source, such as an LED with a luminescent material layer not in physical contact with a die of the LED. Hence, in specific embodiments the light source may be a light source that during operation emits at least light at wavelength selected from the range of 380-470 nm. Especially, the fourth solid state light source may be configured to generate fourth light source light having a wavelength selected from the wavelength range of 430-490 nm, such as from the range of 440-490 nm, like from the range of 440-470 nm. The fourth light source light may thus, in embodiments, have a wavelength in the blue wavelength range. However, other wavelengths may also be possible. This light may partially be converted by the luminescent material. In embodiments, the light generating device may (thus) comprise a luminescent material. In embodiments, the fourth light generating device may comprise a PC- LED. In embodiments, the fourth light generating device may be configured to generate fourth device light comprising the fourth luminescent material light. Optionally, in 2023PF80226 16 embodiments, the fourth device light may also comprise (unconverted) fourth light source light. In embodiments, at least 80%, such as at least 90%, especially at least 95%, including 100% of the fourth device light may comprise the fourth luminescent material light, i.e., phosphor-converted LED light. In some embodiments, the fourth device light may comprise part of the fourth light source light. In embodiments, the fourth solid state light source may be configured to provide fourth light source light to the luminescent material arrangement. Therefore, in embodiments, the luminescent material arrangement may be configured downstream of the fourth solid state light source. In embodiments, the luminescent material arrangement may comprise a fourth luminescent material. Especially, the fourth luminescent material may be configured downstream of the fourth solid state light source. The fourth luminescent material may thus be configured in a light-receiving relationship with the fourth solid state light source. In embodiments, the fourth luminescent material may be configured to convert at least part of the fourth light source light received by the fourth luminescent material into fourth luminescent material light. Especially, in embodiments, the fourth luminescent material may be configured to convert at least 60%, such as at least 70%, like at least 80%, especially at least 90%, more especially at least 95% of the fourth light source light receivedby the fourth luminescent material into fourth luminescent material light. In someembodiments, the fourth luminescent material may be configured to convert at least 98%, such as at least 99%, or even 100% of the fourth light source light received by the fourth luminescent material into fourth luminescent material light. In embodiments, the (fourth device light, especially the) fourth luminescent material light may have in the visible wavelength range (i.e., the range of 380-780 nm) a fourth spectral power distribution. The fourth spectral power distribution may especially have a fourth centroid wavelength (λc4). In embodiments, the fourth centroid wavelength (λc4) may be selected from the wavelength range of 480-590 nm, such as from the wavelength range of 490-580 nm, especially from the wavelength range of 500-580 nm, like from the wavelength range of 500-550 nm, especially from the wavelength range of 505-545 nm. Especially, in embodiments, the (fourth device light, especially the) fourth luminescent material light may have a wavelength in the green-yellow wavelength range. Hence, in embodiments, the fourth device light may be green-yellow light. Further, in embodiments, at least 70%, such as at least 80%, like at least 90%, especially at least 95%, more especially at least 98% of the fourth device light may be fourth luminescent material light. Hence, in some embodiments, essentially all of the fourth device light (i.e., 100%) may be fourth luminescent material light. 2023PF80226 17 However, in other embodiments, the fourth device light may be a combination of fourth luminescent material light and unconverted fourth light source light. Note that othercontributions of light to the fourth device light may be possible as well, e.g., the lightgenerating system (especially the luminescent material arrangement) may comprise a third luminescent material (configured to convert at least part of the fourth light source light into third luminescent material light) such that the fourth device light may also comprise third luminescent material light. Hence, in specific embodiments, the light generating system may comprise a fourth light generating device configured to provide fourth device light having a wavelength selected from the range of 500-580 nm; wherein the fourth light generating device comprises a fourth solid state light source configured to generate fourth light source light; wherein the fourth light generating device is a phosphor-converted light-emitting diode comprising a fourth luminescent material configured to convert at least part of the fourth lightsource light into fourth luminescent material light, wherein the fourth device light comprisesat least part of the fourth luminescent material light; and wherein the fourth device light is green-yellow light. Such embodiments may be beneficial as the addition of the fourth light generating device may enable tuneability of the spectral properties of the system light such as the spectral power distribution or the color point. Furthermore, the addition of the fourth light generating device may enable the generation of white system light with a tunable correlated color temperature using the light generating system. The use of a phosphor-converted light- emitting diode may further provide the benefit of relatively high luminous efficiency. Thus, in embodiments, in an operational mode of the light generating system the system light may comprise (one or more of) the first device light, the second device light, the third device light, and the fourth device light. Hence, in embodiments, in an operational mode of the light generating system the system light may comprise the first luminescent material light, the second device light, and one or more of the second luminescent material light, the third device light, and the fourth device light (and optionally unconverted first light source light and unconverted fourth light source light). As indicated above, the luminescent material arrangement may thus comprise the first luminescent material and optionally one or more of the second luminescent material, (a third luminescent material,) and the fourth luminescent material. Embodiments of the first luminescent material have been described above. In embodiments, the second luminescent material and optionally the fourth luminescent material may comprise a luminescent material of the type A3B5O12:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In, and Sc. Addition of such luminescent 2023PF80226 18 materials to the luminescent material arrangement may provide a broader spectral powerdistribution of the luminescent material light and ultimately the light generating system.Hence, such embodiments may provide further tuning of the spectral properties such as spectral power distribution, color point and correlated color temperature of the system light. In embodiments, the second luminescent material may comprise a different luminescent material from the fourth luminescent material. In other embodiments, the second luminescent material and the fourth luminescent material may be essentially the same luminescent material. The term “luminescent material” may especially refer to a material that can convert first radiation, especially one or more of UV radiation and blue radiation, into second radiation. In general, the first radiation and second radiation have different spectral power distributions. Hence, instead of the term “luminescent material”, also the terms “luminescent converter” or “converter” may be applied. In general, the second radiation has a spectral power distribution at larger wavelengths than the first radiation, which is the case in so-called down-conversion. In specific embodiments, however the second radiation has a spectral power distribution with intensity at smaller wavelengths than the first radiation, which is the case in so-called up-conversion. In embodiments, the “luminescent material” may especially refer to a material that can convert radiation into e.g. visible and / or infrared light. For instance, in embodiments the luminescent material may be able to convert one or more of UV radiation and blue radiation, into visible light. The luminescent material may in specific embodiments also convert radiation into infrared radiation (IR). Hence, upon excitation with radiation, the luminescent material 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 (λex<λem), though in specific embodiments the luminescent material may comprise up-converter luminescent material, i.e. radiation with a larger wavelength is converted into radiation with a smaller wavelength (λex>λem). 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. Hence, the term “first luminescent material” or “second luminescent material” may each independently refer to a plurality of different 2023PF80226 19 luminescent materials (each complying with the herein indicated conditions for the respective “first luminescent material” or “second luminescent material”).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. In embodiments, luminescent materials may be selected from garnets and nitrides, especially doped with trivalent cerium or divalent europium, respectively. The term “nitride” may also refer to oxynitride or nitridosilicate, etc. Alternatively or additionally, the luminescent material(s) may be selected from silicates, especially doped with divalent europium. The luminescent material may thus, in embodiments, comprise a second (and optionally fourth) luminescent material of the type A3B5O12:Ce, wherein A in embodiments comprises one or more of Y, La, Gd, Tb and Lu, especially (at least) one or more of Y, Gd, Tb and Lu, and wherein B in embodiments comprises one or more of Al, Ga, In and Sc. Especially, A may comprise one or more of Y, Gd and Lu, such as especially one or more of Y and Lu. Especially, B may comprise one or more of Al and Ga, more especially at least Al, such as essentially entirely Al. Hence, especially suitable luminescent materials are cerium comprising garnet materials. Embodiments of garnets especially include A3B5O12 garnets, wherein A comprises at least yttrium or lutetium and wherein B comprises at least aluminum. Such garnets may be doped with cerium (Ce), with praseodymium (Pr) or a combination of cerium and praseodymium; especially however with Ce. Especially, B may comprise aluminum (Al); however, in addition to aluminum, B may also partly comprise gallium (Ga) and / or scandium (Sc) and / or indium (In), especially up to about 20% of B, more especially up to about 10 % of B (i.e. the B ions essentially consist of 90 or more mole % of Al and 10 or less mole % of one or more of Ga, Sc and In); B may especially comprise up to about 10% gallium. In another variant, B and O may at least partly be replaced by Si and N. The element A may especially be selected from the group consisting of yttrium (Y), gadolinium (Gd), terbium (Tb) and lutetium (Lu). Further, Gd and / or Tb are especially only present up to an amount of about 20% of A. In a specific embodiment, the garnet luminescent material comprises (Y1-xLux)3B5O12:Ce, wherein x is equal to or larger than 0 and equal to or smaller than 1. The term “:Ce”, indicates that part of the metal ions (i.e. in the garnets: part of the “A” ions) in the luminescent material is replaced by Ce. For instance, in the case of (Y1- xLux)3Al5O12:Ce, part of Y and / or Lu is replaced by Ce. This is known to the person skilled in 2023PF80226 20 the art. Ce will replace A in general for not more than 10%; in general, the Ce concentration will be in the range of 0.1 to 4%, especially 0.1 to 2% (relative to A). Assuming 1% Ce and 10% Y, the full correct formula could be (Y0.1Lu0.89Ce0.01)3Al5O12. Ce in garnets is substantially or only in the trivalent state, as is known to the person skilled in the art. In embodiments, the second (and optionally fourth) luminescent material (thus) comprises A3B5O12 wherein in specific embodiments at maximum 10% of B-O may be replaced by Si-N. In specific embodiments the second (an optionally fourth) luminescent material comprises (Yx1A’x2Cex3)3(Aly1B’y2)5O12, wherein x1+x2+x3=1, wherein x3>0, wherein 0<x2+x3≤0.2, wherein y1+y2=1, wherein especially 0≤y2≤0.2, wherein A’ comprises one or more elements selected from the group consisting of lanthanides, and wherein B’ comprises one or more elements selected from the group consisting of Ga, In and Sc. In embodiments, x3 is selected from the range of 0.001-0.1. In the present invention, especially x1>0, such as >0.2, like at least 0.8. Garnets with Y may provide suitable spectral power distributions. In specific embodiments at maximum 10% of B-O may be replaced by Si-N. Here, B in B-O refers to one or more of Al, Ga, In and Sc (and O refers to oxygen); in specific embodiments B-O may refer to Al-O. As indicated above, in specific embodimentsx3 may be selected from the range of 0.001-0.04. Especially, such luminescent materials mayhave a suitable spectral distribution (see however below), have a relatively high efficiency, have a relatively high thermal stability, and allow a high CRI (optionally in combination with (the) light of other sources of light as described herein). Hence, in specific embodiments A may be selected from the group consisting of Lu and Gd. Alternatively or additionally, B may comprise Ga. Hence, in embodiments the luminescent material comprises (Yx1(Lu,Gd)x2Cex3)3(Aly1Gay2)5O12, wherein Lu and / or Gd may be available. Even more especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3≤0.1, and wherein 0≤y2≤0.1. Further, in specific embodiments, at maximum 1% of B-O may be replaced by Si- N. Here, the percentage refers to moles (as known in the art); see e.g. also EP3149108. In yet further specific embodiments, the luminescent material comprises (Yx1Cex3)3Al5O12, wherein x1+x3=1, and wherein 0<x3≤0.2, such as 0.001-0.1. Further, in embodiments, the second (an optionally fourth) luminescent material may include a luminescent material such as (Yx1’Lux2’A’x3’Cex4’)3B5O12, wherein x1’+x2’+x3’+x4’=1, wherein x4’ may be selected from the range of 0.001-0.1. Further, in embodiments, the second luminescent material may comprise at least two luminescent 2023PF80226 21 materials of the type A3B5O12:Ce3+, such as at least (Yx1’Lux2’A’x3’Cex4’)3B5O12and (Yx1”Lux2”A’x3”Cex4”)3B5O12. In such embodiments, the second luminescent material may comprise a primary second luminescent material such as (Yx1’Lux2’A’x3’Cex4’)3B5O12, wherein x1’ ≥ x2’, wherein 0.001 ≤ x4’ ≤ 0.1, wherein A’ comprises one or more of La, Gd, and Tb, and wherein B comprises one or more of Al, Ga, In, and Sc. Further, in such embodiments, the second luminescent material may comprise a secondary second luminescent material such as (Yx1”Lux2”A’x3”Cex4”)3B5O12, wherein x1”+x2”+x3”+x4”=1, wherein x2" > x2’, wherein 0.001 ≤ x4” ≤ 0.1, wherein A’ comprises one or more of La, Gd, and Tb, and wherein B comprises one or more of Al, Ga, In, and Sc. In embodiments, the secondary second luminescent material may thus comprise on a molar basis more Lu than the primary second luminescent material. Further, in embodiments, the primary second luminescent material may comprise on a molar basis more Y than the secondary second luminescent material, x1’ >x1”. In embodiments, x2’ may be equal to zero. Further, in embodiments, one or more of x2’,x3’, and x3” may be equal to zero. In embodiments, x4’ may be equal to x4”. Yet, in embodiments, x4’ may be different from x4”, wherein (both) x4’ and x4” may be individually selected from the range of 0.001-0.1. Hence, in embodiments, the second luminescent material may comprise a primary second luminescent material such as (Yx1’Lux2’Cex4’)3B5O12(wherein x1’+ x2’+ x4’ = 1) and a secondary second luminescent material such as (Yx1”Lux2”Cex4”)3B5O12 (wherein x1”+ x2”+ x4” = 1), wherein x2” > x2’, and wherein in specific embodiments x2’ = 0. Further, in embodiments, the second luminescent material may include a luminescent material such as (Lux1A’x2Cex3)3(Aly1B’y2)5O12, where x1, x2, x3, y1, and y2 are as defined above. Especially, in embodiments, x1+x2+x3=1, wherein x1≥0.5. Further, in embodiments, the second luminescent material may comprise at least two luminescent materials of the type A3B5O12:Ce3+, such as at least (Yx1A’x2Cex3)3(Aly1B’y2)5O12and (Lux1A’x2Cex3)3(Aly1B’y2)5O12. In such embodiments, the second luminescent material may comprise (i) a primary second luminescent material such as (Yx1A’x2Cex3)3(Aly1B’y2)5O12, wherein A’ comprises one or more of La, Gd, Tb, and Lu, and (ii) a secondary second luminescent material such as (Lux1A’x2Cex3)3(Aly1B’y2)5O12, wherein A’ comprises one or more of Y, La, Gd, and Tb. In such embodiments, for the primary second luminescent material and the secondary second luminescent material may individually apply that x1+x2+x3=1, that x1≥0.5, and that B’ comprises one or more of Ga, In, and Sc. In embodiments, the primary second luminescent material may thus comprise on a molar basismore Y than Lu. Conversely, the secondary second luminescent material may comprise on a 2023PF80226 22 molar basis more Lu than Y. Note that in embodiments, x2 = 0, and the primary second luminescent material may (essentially) consist of (Yx1Cex3)3(Aly1B’y2)5O12, wherein x1+x3 = 1. Similarly, the secondary second luminescent material may (essentially) consist of (Lux1Cex3)3(Aly1B’y2)5O12, wherein x1+x3 = 1. Such a composition of second luminescent material may provide a broader spectral power distribution of the second luminescent material light. For instance, the primary second luminescent material may be configured to provide primary second luminescent material light, and the secondary second luminescent material may be configured to provide secondary second luminescent material light, wherein a centroid wavelength of the primary second luminescent material light may be larger than a centroid wavelength of the secondary second luminescent material light. In embodiments, the second luminescent material may comprise at least 10 wt.%, such as at least 25 wt.%, especially at least 40 wt.% primary second luminescent material. Conversely, the second luminescent material may comprise at least 10 wt.%, suchas at least 25 wt.%, especially at least 40 wt.% secondary second luminescent material.Further, in embodiments, the second luminescent material may comprise at most 90 wt.%, such as at most 75 wt.%, especially at most 60 wt.% primary second luminescent material. Additionally or alternatively, in embodiments, the second luminescent material may comprise at most 90 wt.%, such as at most 75 wt.%, especially at most 60 wt.% secondary second luminescent material. As can be derived from the above, the term “different luminescent materials” may refer to luminescent materials that are different, or to two compositions, each including at least one luminescent material in common, but wherein the compositions differ. For instance, a primary second luminescent material comprising luminescent materials A and B, and a secondary second luminescent material comprising only A or only B, or comprising both A and B, but in a different weight ratio. Such primary second luminescent material and secondary second luminescent material may have different spectral power distributions of their respective luminescent material light. Alternatively or additionally, the second luminescent material may comprise a luminescent material of the type A3Si6N11:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, such as in embodiments one or more of La and Y. Alternatively or additionally, also other luminescent materials may be applied. For instance quantum dots and / or organic dyes may be applied and may optionally be embedded in transmissive matrices like e.g. polymers, like PMMA, or polysiloxanes, etc. etc. 2023PF80226 23 Quantum dots are small crystals of semiconducting material generally having a width or diameter of only a few nanometers. When excited by incident light, a quantum dot emits light of a color determined by the size and material of the crystal. Light of a particular color can therefore be produced by adapting the size of the dots. Most known quantum dots with emission in the visible range are based on cadmium selenide (CdSe) with a shell such as cadmium sulfide (CdS) and zinc sulfide (ZnS). Cadmium free quantum dots such as indium phosphide (InP), and copper indium sulfide (CuInS2) and / or silver indium sulfide (AgInS2) can also be used. Quantum dots show very narrow emission band and thus they show saturated colors. Furthermore the emission color can easily be tuned by adapting the size of the quantum dots. Any type of quantum dot known in the art may be used in the present invention. However, it may be preferred for reasons of environmental safety and concern to use cadmium-free quantum dots or at least quantum dots having a very low cadmium content. Instead of quantum dots or in addition to quantum dots, also other quantum confinement structures may be used. The term “quantum confinement structures” should, in the context of the present application, be understood as e.g. quantum wells, quantum dots, quantum rods, tripods, tetrapods, or nano-wires, etcetera. Organic phosphors can be used as well. Examples of suitable organic phosphor materials are organic luminescent materials based on perylene derivatives, for example compounds sold under the name Lumogen® by BASF. Examples of suitable compounds include, but are not limited to, Lumogen® Red F305, Lumogen® Orange F240, Lumogen® Yellow F083, and Lumogen® F170. Different luminescent materials may have different spectral power distributions of the respective luminescent material light. Alternatively or additionally, such different luminescent materials may especially have different color points (or dominant wavelengths). As indicated above, other luminescent materials may also be possible. Hence, in specific embodiments the luminescent material is selected from the group of divalent europium containing nitrides, divalent europium containing oxynitrides, divalent europium containing silicates, cerium comprising garnets, and quantum structures. Quantum structures may e.g. comprise quantum dots or quantum rods (or other quantum type particles) (see above). Quantum structures may also comprise quantum wells. Quantum structures may also comprise photonic. In embodiments, the light generating system may be configured such that in an operational mode of the light generating system the system light comprises at least the first 2023PF80226 24 device light, the second device light and optionally one or more of the third device light and the fourth device light. In specific embodiments, as described above, the system light may comprise the first luminescent material light and the second device light (i.e., the system light may be red light). In other embodiments, the system light may comprise the (red) first luminescent material light, the (yellow-green) second luminescent material light and the (red) second device light. In yet other embodiments, the system light may comprise (unconverted blue) first light source light, the (red) first luminescent material light, the (green-yellow)second luminescent material light and the (red) second device light. In yet otherembodiments, the system light may comprise the (red) first luminescent material light, the (red) second light source light, the (blue) third device light, and the (green) fourth device light. Other possible combinations of light contributions to the system light using the above described elements of the light generating system will be known to the skilled person. Hence, in some embodiments, the system light may be white light. With such embodiments it may be possible to provide a light generating system which is able to generate a white (or whitish) light spectrum with an improved red saturation index (RSI) and / or an improved lumen efficiency. Thus, in embodiments, in an operational mode of the light generating system, the system light may be white light. The term “white light”, and similar terms, herein, is known to the person skilled in the art. In general, if a light source is indicated to generate white light, it may especially relate to light having a correlated color temperature (CCT) between about 1500 K and 20000 K, such as between 2000 and 20000 K, especially 2700- 20000 K, for general lighting especially in the range of about 2000-7000 K, such as in the range of 2700 K and 6500 K. More especially, in embodiments, in an operational mode the system light may be white light having a correlated color temperature selected from the range of 1500-10000 K, such as selected from the range of 1500-8000 K, like selected from the range of 1700-6500 K. Additionally or alternatively, in such embodiments, the system light may be white light having a color rendering index of at least 70, especially at least 80, such as at least 90. Such embodiments may be beneficial for applications where high brightness light sources may be desired, such as e.g. spots, stage-lighting, headlamps, home and office lighting, and automotive lighting. The light generating system may further comprise a control system. The control system may, in embodiments, be configured to individually control the (first, second, and optionally third and / or fourth) light generating devices. Especially, the control system may be configured to control the first light generating device and the second light generating 2023PF80226 25 device. In particular, in embodiments, the control system may be configured to control the first light generating device and the second light generating device while maintaining a fixedcolor point of the system light. Herein, the term “fixed” may refer to a predetermined (or pre-set) value that may not be changed during use. Hence, the phrase “fixed color point” may refer to a color point that may not change over time during use of the light generating system. For example, in embodiments, the color point may be predetermined, i.e. factory-set. Additionally or alternatively, in embodiments, the control system may be configured to control the first light generating device and the second light generating device while maintaining a fixed correlated color temperature (CCT) of the system light. Analogous to the fixed color point, the phrase “fixed correlated color temperature” may refer to a CCT that may not change over time during use of the light generating system. For example, in embodiments, the CCT may be predetermined, i.e., factory-set. Hence, in embodiments, the light generating system may comprise a control system, wherein the control system may be configured to individually control the light generating devices; wherein the control system may be configured to control the first light generating device and second light generating device while maintaining one or more of (i) a fixed color point of the system light, and (ii) a fixed correlated color temperature of the system light. Furthermore, in embodiments, the light generating system may comprise an optical sensor. In embodiments, the optical sensor may be configured to sense one or more of the first device light and the system light. The optical sensor may especially be configured (i) to sense one or more of the first device light and the system light and (ii) to generate a related optical sensor signal. Such a related optical sensor signal may be beneficial as it may provide feedback on the contribution of the first device light, especially the first luminescent material light, in the system light. Such feedback may indicate the level of decay (or deterioration due to hydrolysis and / or light-based damage) of the first luminescent material over time. The control system may then be configured to respond to said feedback by individually controlling the first light generating device and the second light generating device, such that the second device light may compensate for the loss in first device light. In embodiments, as the first centroid wavelength (λc1) and the second centroid wavelength (λc2) may be similar or even equal, such control (as described previously) of the first light generating device and the second light generating device may facilitate maintenance of one or more of the fixed color point and the fixed correlated color temperature of the system light. The control system may, in embodiments, be configured to individually control the (first, second, and optionally third and / or fourth) light generating devices in 2023PF80226 26 dependence of a predefined radiant-flux-time relation. The predefined relation of the radiant flux (of especially first device light) and the (operation) time may comprise predefinedreference values of radiant flux to operation time (“lookup table”), e.g. on the basis of data orreference measurements or on the basis of a prediction (of the behavior of the first luminescent material). The control system may then be configured to control at least the second light generating device such that the radiant flux of the second device light may be changed (especially on the basis of the (operation) time of the first light generating device(and the predefined relation between this operation time and a radiant flux of the first lightgenerating device). In general, the longer the operation time of the first light generating device, the higher the radiant flux of the second light generating device should become. In other words, over time the control system may be configured to increase the radiant flux of the second light generating device based on the predefined relation. In alternative embodiments, the control system may, in embodiments, be configured to individually control the (first, second, and optionally third and / or fourth) light generating devices in dependence of the optical sensor signal and a predefined relation representing an intensity-time relation. Hence, in such embodiments, the control system may be configured to increase the (luminous) intensity of the second light generating device based on the predefined relation. Therefore, in embodiments the control system may be configured to individually control one or more of the light generating devices in dependence of a predefined radiant flux-time relation of the first light generating device. More especially, the control system may be configured to control (at least) the second light generating device in dependence of the predefined radiant flux-time relation of the first light generating device. The optical sensor may thus, in embodiments, be configured to (i) sense or detect at least the (contribution of) first device light in the system light, and (ii) provide an optical sensor signal to the control system based on its detection. Hence, in embodiments, the sensor may be configured functionally (such as communicatively) coupled with the control system. In response, the control system may be configured to control the radiant flux and / or luminous intensity of the light generating devices in dependence of the optical sensor signal and the predefined relation. Hence, in specific embodiments, the light generating system may comprise an optical sensor configured to sense one or more of (i) the first device light and the system light, and generate a related optical sensor signal, wherein the control system may be configured to individually control the light generating devices in dependence of the optical sensor signal and a predefined relation representing a radiant flux-time relation. 2023PF80226 27 Additionally or alternatively, in embodiments, the control system may be configured to individually control one or more of the first light generating device, the second light generating device, and optionally the third light generating device and / or the fourth light generating device. Especially, in embodiments, the control system may be configured to individually control the light generating devices to control one or more of the spectral power, the color point, and the correlated color temperature of the system light. The term “controlling” and similar terms especially refer at least to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior to the element (determining the behavior or supervising the running of an element), etc., such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may additionally include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also imposing behavior on an element and monitoring the element. The controlling of the element can be done with a control system, which may also be indicated as “controller”. The control system and the element may thus at least temporarily, or permanently, functionally be coupled. The element may comprise the control system. In embodiments, the control system and element may not be physically coupled. Control can be done via wired and / or wireless control. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface. The control system may also be configured to receive and execute instructions from a remote control. In embodiments, the control system may be controlled via an App on a device, such as a portable device, like a Smartphone or I-phone, a tablet, etc.. The device is thus not necessarily coupled to the lighting system, but may be (temporarily) functionally coupled to the lighting system. 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 controlledby an external control system which has access to the lighting system on the basis ofknowledge (input by a user interface of with an optical sensor (e.g. QR code reader) of the 2023PF80226 28 (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. 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 alsobe 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. 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 amode in dependence of a sensor signal or a (time) scheme, may also be possible. Theoperation mode may in embodiments also refer to a system, or apparatus, or device, that can only operate in a single operation mode (i.e. “on”, without further tunability). Hence, in embodiments, the control system may control the spectral power distribution (, especially e.g. the color point) of the system light 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. In specific embodiments, the first light generating device may comprise a phosphor-converted light-emitting diode (PC-LED) comprising the first luminescent material. Additionally or alternatively, in embodiments, the first light generating device may comprise a phosphor-converted light-emitting diode (PC-LED) comprising the first luminescent material and the second luminescent material. The light generating system may further, in embodiments, comprise a support configured to support the first light generating device, the second light generating device, and (optionally) one or more of the third light generating device and the fourth light generating device. In embodiments, the first (solid state) light source may be comprised by a first light generating device. Especially, in embodiments, the first light generating device may comprise the first light source and the first luminescent material. In such embodiments, the first light generating device may especially be a phosphor-converted light emitting diode (PC-LED). In embodiments, the first light generating device may be configured to generate 2023PF80226 29 first device light comprising the first luminescent material light. Optionally, in embodiments, the first device light may also comprise (unconverted) first light source light. In embodiments, at least 80%, such as at least 90%, especially at least 95%, including 100% of the first device light may comprise the first luminescent material light, i.e., phosphor- converted (red) LED light. In embodiments, the luminescent material arrangement, especially at least the first luminescent material, may thus be configured downstream of the first light source. Therefore, the luminescent material arrangement may comprise a luminescent element. The luminescent element may have any shape. In general, however, the luminescent element may comprise a luminescent body comprising two essentially parallel faces (i.e. a first side and a second side), defining a height (of the luminescent body). Further, the luminescent body may comprise a third side (or “edge face”), bridging the first side and second side. The edge facemay be curved in one or two dimensions. The edge face may be planar. The luminescentbody 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 body may have a circular cross-section, an oval cross-section, square, or non-square rectangular. In embodiments, the luminescent body may have an n-gonal cross-section, wherein n is at least3, like 4 (square or rectangular cross-section), 5 (pentagonal cross-section), 6 (hexagonalcross-section), 8 (octagonal cross-section) or higher. The first side and second side may also be indicated as “main faces”, as they may especially provide the largest external area of the luminescent body. Perpendicular to the afore-mentioned cross-section, may be another cross- section, which may in embodiments be rectangular. Hence, the luminescent body may e.g. have a cubic shape, a (non-cubic) cuboid shape, an n-gonal prism shape with n being at least 5 (such as pentagonal prism, hexagonal prism), and a cylindrical shape. Other shapes, however, may also be possible. Especially, the luminescent body may have a cuboid shape, a cylindrical shape, or an n-gonal prism shape wherein n is 6 or 8. In embodiments, the luminescent body has lateral dimensions width or length (W or L) or diameter (D) and athickness or height (H). In embodiments, (i) D ≥ H or (ii) W ≥ H and / or L ≥ H. Further, theluminescent body may be transparent or light scattering. In embodiments, the luminescent body may comprise a ceramic luminescent material. In specific embodiments, LB ≤ 10 mm, such as especially LB≤ 5mm, more especially LB≤ 3mm, most especially LB≤ 2 mm. In specific embodiments, WB ≤ 10 mm, such as especially WB ≤ 5mm, more especially WB ≤ 3mm, most especially WB ≤ 2 mm. In specific embodiments, DB ≤ 10 mm, such as especially DB ≤ 5mm, more especially DB ≤ 3mm, most especially DB ≤ 2 mm. Further, the luminescent 2023PF80226 30body may have lateral dimensions (width / diameter) in the range 100 µm – 10 mm. In yetfurther specific embodiments, (i) DB> HBor (ii) WB> HBand LB> HB. Especially, the lateral dimensions like length, width, and diameter are at least 2 times, like at least 5 times, larger than the height. In specific embodiments, the luminescent body has a first length LB, a first height HB, and a first width WB, wherein HB≤ 0.5*LBand HB≤ 0.5*WB. In embodiments, the luminescent body may be a (small) tile. In alternative embodiments, the luminescent element may comprise a luminescent layer. The luminescent layer may be a self-supporting layer. Further, in embodiments, the luminescent layer may be a coating. The luminescent body may also comprise a luminescent coating on a support (especially a light transmissive support in the transmissive mode, or a reflective support in the reflective mode). The luminescent element may also be an (elongated) encapsulant. Especially, the encapsulant may be configured covering the light generating devices and optionally a support or carrier. Especially, the luminescent element may essentially be self-supporting. In embodiments, the luminescent element may comprise a light transmissive body, wherein the luminescent material is embedded. For instance, the luminescent element may comprise a glass body, with luminescent material embedded therein. Or, the glass as such may be luminescent. In other embodiments, the luminescent element may comprise a polymeric body, with luminescent material embedded therein. In embodiments, the luminescent material arrangement may also comprise multiple luminescent elements, such as 1-4 luminescent elements, especially 1-3 luminescent elements. For example, in embodiments, the luminescent material arrangement may comprise a luminescent element comprising the first luminescent material configured downstream from the first solid state light source and another luminescent element comprising the fourth luminescent material configured downstream from the fourth solid state light source. However, in other embodiments, the first luminescent material and the fourth luminescent material may be comprised by essentially the same luminescent element, such as e.g. an encapsulant configured over (at least) both the first solid state light source and the fourth solid state light source. Hence, in embodiments, the luminescent material arrangement may comprise one or more luminescent elements, such as e.g. a layer, a body, or an encapsulant. In embodiments, the light generating system may thus comprise light generating devices and the luminescent material arrangement. Furthermore, in embodiments, the light generating system may comprise a support configured to support one or more of thelight generating devices and optionally the luminescent material arrangement. In 2023PF80226 31 embodiments, the support may be rigid. In other embodiments, the support may be flexible, such as e.g. a flexible printed circuit board (PCB). In specific embodiments, the light generating system may comprise a LED strip comprising the support. Such embodiments may be beneficial as they may enable relatively cheap and facile incorporation of the light generating system in a desired application, such as in a luminaire. The use of a COB, a filaments or a strip over individual LED’s may increase the efficiency of production. Referring back to the (solid-state) light generating devices, in embodiments, the light generating device may thus comprise a luminescent material. In embodiments, the light generating device may comprise a PC LED. In other embodiments, the light generating device may comprise a direct LED (i.e. no phosphor). In embodiments, the light generating device may comprise a laser device, like a laser diode. In embodiments, the light generating device may comprise a superluminescent diode. Hence, in specific embodiments, the light source may be selected from the group of laser diodes and superluminescent diodes. In other embodiments, the light source may comprise an LED. In a specific embodiment, the light source comprises a solid state LED light source (such as an LED or laser diode (or “diode laser”)). The term “light source” may also relate to a plurality of light sources, such as 2-2000 (solid state) LED light sources. Hence, the term LED may also refer to a plurality of LEDs. The term “light source” may thus also relate to a plurality of (essentially identical (or different)) light sources, such as 2-2000 solid state light sources. 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, such as an LED, 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 an 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). 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, e.g. having band widths as known for lasers. 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. For instance, a solid state light source as such, like a blue LED, is a light source. A combination of a solid state light source (as light generating 2023PF80226 32 element) and a light converter element, such as a blue LED and a luminescent material comprising element, optically coupled to the solid state light source, may also be a light source (but may also be indicated as light generating device). Hence, a white LED is a light source (but may e.g. also be indicated as (white) light generating device). In embodiments, the term “light source” may 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. Especially, the term “light generating device” may be used to address a light source and further (optical components), like an optical filter and / or a beam shaping element, etc. The phrases “different light sources” or “a plurality of different light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from at least two different bins. Likewise, the phrases “identical light sources” or “a plurality of same light sources”, and similar phrases, may in embodiments refer to a plurality of solid-state light sources selected from the same bin. The term “solid state light source”, or “solid state material light source”, and similar terms, may especially refer to semiconductor light sources, such as a light emitting diode (LED), a laser diode, a multi-junction light emitting diode, or a superluminescent diode. Instead of the term “solid state light source” also the term “semiconductor-based light source” may be applied. Hence, the term “semiconductor-based light source” may e.g. referto one or more of a light emitting diode (LED), a laser diode, a multi-junction light emittingdiode, and a superluminescent diode. The term “light source” may also refer to a semiconductor light-emitting device, such as a light emitting diode (LEDs), a laser diode, a resonant cavity light emitting diode (RCLED), a vertical cavity laser diode (VCSELs), an edge emitting laser (EEL), a photonic crystal surface emitting laser (PCSEL), a vertical external cavity surface emitting laser (VECSEL), etc... The term “light source” may also refer to an organic light-emitting diode (OLED), such as a passive-matrix (PMOLED) or an active-matrix (AMOLED). In a specific embodiment, the light source comprises a solid-state light source (such as an LED or laser diode). In an embodiment, the light source comprises an LED (light emitting diode). The terms “light source” or “solid state light source” may also refer to a superluminescent diode (SLED). A light-emitting diode (LED) is especially a semiconductor light source that emits light when current flows through it. Electrons in the semiconductor may recombine with electron holes, releasing energy in the form of photons. The color of the light 2023PF80226 33 (corresponding to the energy of the photons) may be determined by the energy required for electrons to cross the band gap of the semiconductor. A laser diode (or diode laser) may be a semiconductor device substantially similar to a light-emitting diode in which a diode pumped directly with electrical current can create lasing conditions at the diode's junction. This is known to a person skilled in the art. 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, refer to a laser diode (or diode laser). A laser may be combined with an upconverter in order to arrive at shorter (laser) wavelengths. For instance, with some (trivalent) rare earth ions upconversion may be obtained or with non-linear crystals upconversion can be obtained. Alternatively, a laser can be combined with a downconverter, such as a dye laser, to arrive at longer (laser) wavelengths. The term “solid state material laser”, and similar terms, may refer to a solid state laser like based on a crystalline or glass body doped with ions, like transition metal ions and / or lanthanide ions, to a fiber laser, to a photonic crystal laser, to a semiconductor laser, such as e.g. a vertical cavity surface-emitting laser (VCSEL), etc. Superluminescent diodes are known in the art. A superluminescent diode may be indicated as a semiconductor device which may be able to emit low-coherence light of a broad spectrum like an LED, while having a brightness in the order of a laser diode. A superluminescent diode may especially be a semiconductor light source, where the spontaneous emission light is amplified by stimulated emission in the active region of the device. Such emission is called “super luminescence”. Hence, in embodiments, the solid state light source may comprise a superluminescent diode. For instance, in further specific embodiments, the solid state light source may comprise a GaN-based superluminescent diode, or an InGaN-based superluminescent diode, or an AlGaN-based superluminescent diode. The term “light source” may also refer to a chip scaled package (CSP). A CSP may comprise a single solid state die with provided thereon a luminescent material comprising layer. The term “light source” may also refer to a midpower package. A midpower package may comprise one or more solid state die(s). The die(s) may be covered by a luminescent material comprising layer. The die dimensions may be equal to or smaller 2023PF80226 34 than 2 mm, such as in the range of e.g.0.2-2 mm. Hence, in embodiments the light source comprises a solid state light source. Further, in specific embodiments, the light source comprises a chip scale packaged LED. Herein, the term “light source” may also especially refer to a small solid state light source, such as having a mini size or micro size. For instance, the light sources may comprise one or more of mini LEDs and micro LEDs. Especially, in embodiment the light sources comprise micro LEDs or “microLEDs” or “µLEDs”. Herein, the term mini size or mini LED especially indicates to solid state light sources having dimensions, such as die dimension, especially length and width, selected from the range of100 µm – 1 mm. Herein, the term µ size or micro LED especially indicates to solid state lightsources having dimensions, such as die dimension, especially length and width, selected from the range of 100 µm and smaller. The light source may have a light escape surface. Referring to conventional light sources such as light bulbs or fluorescent lamps, it may be an outer surface of a glass or a quartz envelope. For LED’s it may for instance be the LED die, or when a resin may be applied to the LED die, the outer surface of the resin. In principle, it may also be the terminal end of a fiber. 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 isconfigured to provide a beam of light. This beam of light (thus) escapes from the light exitsurface of the light source. Likewise, a light generating device may comprise a light escape surface, such as an end window. Further, likewise a light generating system may comprise a light escape surface, such as an end window. A position where system light escapes from the light generating system may also be indicated as light exit. This may be a light transmissive window or an opening (in the system). The light transmissive window may in embodiments be provided by an optical component. As described above, the light generating system may, in embodiments, be operated in different operational modes by controlling the different light generating devices in the light generating system. Alternatively, in embodiments, the light generating system (especially the different light generating devices) may not be controllable, i.e., the light generating system may be configured to operate in only one operational mode (i.e. in such embodiments a spectral power distribution of the system light generated in the first operational mode is not controllable). In embodiments, the different light generating devices may be configured spatially separated (but electrically coupled). However, in embodiments, 2023PF80226 35 one or more of the (first, second, third, and optionally fourth) light generating devices may also be configured together, e.g., as a Chip-on-Board or a LED filament. Thus, in embodiments, the light generating system may comprise a Chip-on-board device or a LED filament. Especially, in such embodiments, the luminescent material arrangement (comprising the first luminescent material) may be configured downstream of the first light generating device and the second light generating device. Additionally, in embodiments, the luminescent material arrangement may comprise the second luminescent material. Hence, in embodiments, the light generating system may comprise a Chip-on-Board or a LED filament, wherein the luminescent material arrangement is configured downstream of the first light generating device and the second light generating device; wherein the luminescent material arrangement (optionally) further comprises the second luminescent material. Such embodiments may be beneficial as a CoB system may provide relatively high intensity system light from a relatively small surface area. Further, such a CoB system may reduce the appearance of areas with higher and lower intensity within a lighting device (such as a LED strip), thereby providing a more homogeneous illumination by the lighting device. In embodiments, the light generating system may comprise a Chip-on-Board (CoB). The term “Chip-on-Board” (or “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 printed circuit board (PCB), wherein a single luminescent body is configured in a light-receiving relationship with (all of) said LED chips. 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. In embodiments, the Chip-on-Board may thus comprise at least the first and second, and optionally the third and / or fourth light generating devices. Further, the Chip-on-Board may comprise the luminescent material arrangement. Especially, the luminescent material arrangement may be configured on top of the first and second (and optionally third and / or fourth) light generating devices. Further, in embodiments, the light generating system may comprise a LED filament. LED filaments as such are known, and are e.g. described in US 8,400,051 B2, WO2020016058, WO2019197394, etc., which are herein incorporated by reference. In general, a LED filament may in embodiments comprise (i) a plurality of light emitting diodes (LEDs), arranged on (at least a first major surface of) an elongated carrier, and (ii) anelongated encapsulant covering the plurality of LEDs and at least part of the elongatedcarrier. The LED filament may in embodiments be defined by a filament length LF, a filament 2023PF80226 36 width WF, and a filament thickness TF. The LED filament may further comprise a filament axis of elongation AF. The filament axis of elongation AFmay especially be a straight axis centered on the direction along which the LED filament is elongated. The filament axis of elongation AF may define an axis length LA, wherein the axis length LA may be the length of the LED filament along the filament axis of elongation AF. In some embodiments, the LED filament may be straight. In straight embodiments, the filament length LF may (essentially) be equivalent to the axis length LA. 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, or another curved shape. In curved embodiments, the axis length LAmay be smaller than the filament length LF, such as LA / LF ≤ 0.95, especially LA / LF ≤ 0.75, more especially LA / LF ≤ 0.55. Further, the LED filament may have relatively high aspect ratios (LF / WFor LF / TF), such as at least 10, especially at least 15, such as at least 20, more especially at least 50. Large aspect ratios may better mimic a filament. Yet, in embodiments, the aspect ratio (LF / WF and / or LF / TF) may be at most 200, such as at most 150, especially at most 100. Hence, in specific embodiments, 10*WF≤ LF≤ 200*WF, and 10*TF≤ LF≤ 200*TF. 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. Hence, in embodiments, the elongated carrier may essentially be the support as described above. 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, especially reflective for one or more of the light source light and the LED filament light (see below), such as reflective for at least the light source light and the LED filament light. In specific embodiments, the carrier may be diffuse reflective. The elongated carrier may have (essentially) similar dimensions to the LED filament. Especially, the elongated carrier may (essentially) define the filament length LFand axis length LAof the LED filament. The width WF and thickness TF of the LED filament may be defined by the elongated carrier as well as other components of the LED filament, e.g., the solid state light sources and an encapsulant. 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 2023PF80226 37 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 thesolid state light sources may be mounted onto the second major surface. Hence, inembodiments, the solid state light sources may be arranged, mounted and / or mechanically coupled on / to the carrier, wherein the carrier may especially be configured to mechanically and / or electrically support the LEDs. In embodiments, the solid state light sources may comprise LEDs. Alternatively or additionally, in embodiments, the solid state light sources may comprise diode lasers. Further, the LED filament may comprise one or more of LEDs, laser diodes, a multi-junction light emitting diodes, and superluminescent diodes. Especially, the LED filament comprises a plurality of light emitting diodes (LEDs). The (plurality of) solid state light sources may be arranged in an array (on the elongated carrier), especially over (at least part of) the filament length LF. 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 10-1000, such as 10-200. In embodiments, the solid state light sources may be configured in a 1D (linear) array over at least part of the filament length LF. A first and a last solid state light source may, when measured along the LED filament, have a mutual distance of at least 0.5*LF, even more especially at least 0.7*LF. Further, in embodiments, the solid state light sources may be configured in two 1D 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, such as in embodiments 1 or in embodiments 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. In embodiments, the LED filament may comprise an encapsulant. The encapsulant may especially (at least partly) cover the plurality of solid state light sources. Further, the encapsulant may (at least partly) cover 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 cover all of the solid state light sources. Hence, in embodiments the encapsulant may be configured over a substantial 2023PF80226 38 part of the filament length LFof the LED filament (such as over more than 70% of the filament length LF). The encapsulant may be a continuous coating along the filament length LF, at one or both of the first major and the second major surface. Further, the encapsulant may at least partly cover the solid state light sources, such as in embodiments at least 50% of the total number of solid state light sources in the array, such as at least 75%, especially at least 95%, up to 100%. In embodiments, the encapsulant may comprise one or more of a luminescent material and a light scattering material, especially at least a luminescent material. Especially, in embodiments, the encapsulant may comprise at least the first luminescent material. Hence, the encapsulant comprising at least the first luminescent material may essentially be an embodiment of the luminescent material arrangement as defined for the light generating system. The one or more of the luminescent material and the light scattering material mayespecially be configured embedded in an encapsulant material, e.g. a (flexible) polymermaterial (such as a silicone). In embodiments, the luminescent material may be configured to convert at least part, such as all, of the light source light (generated by the solid state light sources) into luminescent material light. In specific embodiments, the luminescent material may comprise a phosphor such as an inorganic phosphor and / or quantum dots or rods. Further, in embodiments, the light scattering material may be configured to scatter (or “diffuse”) the light source 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 light scattering particles, such as e.g. at least one of BaSO4, A12O3and TiO2particles. In embodiments, the LED filament may be configured to generate filament light, which may comprise one or more of (scattered) light source light and luminescent material light. The term “LED filament light” may refer to the light emitted by the LED filament during operation of the LED filament. Further, the solid state light sources, comprised by the LED filament, may be configured to generate light source light. In embodiments, at least two, such as all, of the solid state light sources may be configured to emit light source light having different spectral power distributions. In other embodiments, at least two, such as all, of the solid state light sources may be configured to provide light source light having essentially the same spectral power distribution. In embodiments, the filament light may comprise the light source light, or may even essentially consist of(scattered) light source light. However, in embodiments wherein the encapsulant maycomprise a luminescent material, the filament light may comprise luminescent material light, 2023PF80226 39 or may even essentially consist of luminescent material light. Further, in embodiments, thefilament light may comprise luminescent material light and at least part of the (non-convertedand / or scattered) light source light. In embodiments, the LED filament may provide filament light with a desired spectral light distribution, e.g., white light having a correlated color temperature selected from the range of 1500-3000 K. In such embodiments, the filament light may comprise luminescent material light and optionally transmitted light source light. Further, the filament light may at least comprise light at a wavelength selected from the range of 380-780 nm, i.e., visible light. In embodiments, the filament light may at least comprise white light. Especially, the filament light may be relatively warm (white) light, such asselected from the range of 1500 – 3000 K, especially selected from 1500 – 2700 K, mostespecially selected from the range of 1800-2700 K. In embodiments, the LED filament may comprise multiple sub-filaments. The light generating system may be part of or may be applied in e.g. office lighting systems, household application systems, shop lighting systems, home lighting systems, accent lighting systems, spot lighting systems, theater lighting systems, fiber-optics application systems, projection systems, self-lit display systems, pixelated display systems, segmented display systems, warning sign systems, medical lighting application systems, indicator sign systems, decorative lighting systems, portable systems, automotive applications, (outdoor) road lighting systems, urban lighting systems, green house lighting systems, horticulture lighting, digital projection, or LCD backlighting. The light generating system (or luminaire) may be part of or may be applied in e.g. optical communication systems or disinfection systems. The terms “visible”, “visible light” or “visible emission” and similar terms refer to light having one or more wavelengths in the range of about 380-780 nm. 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 embodiments, especially for lighting applications, the terms “light” and “radiation” refer to (at least) visible light. 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. etc... The lamp or luminaire may furthercomprise a housing enclosing the light generating system. The lamp or luminaire maycomprise a light window in the housing or a housing opening, through which the system light 2023PF80226 40 may escape from the housing. In yet a further aspect, the invention may also provide 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, an automotive lighting device, and an optical wireless communication device, comprising the light generating system as defined herein. The lighting device may comprise a housing or a carrier, configured to house or support, one or more elements of the light generating system. For instance, in embodiments the lighting device may comprise a housing or a carrier, configured to house or support one or more of the first generating device, the second light generating device, and the luminescent material arrangement. Instead of the terms “lighting device” or “lighting system”, and similar terms, also the terms “light generating device” or “light generating system”, (and similar terms), may be applied. A lighting device or a lighting system may be configured to generate device light (or “lighting device light”) or system light (“or lighting system light”). The lighting device may comprise a light source. The device light may in embodiments comprise one or more of light source light and converted light source light (such as luminescent material light). BRIEF DESCRIPTION OF THE DRAWINGS 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: Figs.1 and 2 schematically depict some embodiments of the light generating system. Fig.3 depicts emission and excitation spectra of the light generating system. Fig.4 schematically depicts some applications of the light generating system in lighting devices. The schematic drawings are not necessarily to scale. DETAILED DESCRIPTION OF THE EMBODIMENTS Fig.1 schematically depicts embodiments of the invention comprising: a light generating system 1000 configured to provide system light 1001. The light generating system 2023PF80226 41 may comprise light generating devices 100 configured to generate device light 101. Furthermore, the light generating system may comprise a luminescent material arrangement 2000 comprising one or more luminescent elements 200 configured to provide luminescent material light 201. As depicted in Fig.1a, in specific embodiments, the light generating system 1000 may comprise (i) a first light generating device 110, (ii) a second light generating device 120, and (iii) a luminescent material arrangement 2000. In embodiments, the first light generating device 110 may comprise a first solid state light source 10 configured to generate first light source light 11. Especially, in embodiments, the first light source light 11 may have a wavelength selected from the wavelength range of 430-490 nm. Moreover, in embodiments, the first light generating device 110 may be configured to generate first device light 111. In embodiments, the luminescent material arrangement 2000 may comprise a first luminescent material 210. The first luminescent material 210 may be configured downstream of the first light source 10. The first luminescent material may especially be configured to convert at least part of the first light source light 11 received by the first luminescent material 210 into first luminescent material light 211. In embodiments, the first luminescent material light 211 may have in the visible wavelength range a first spectral power distribution having a first centroid wavelength (λc1). The first centroid wavelength (λc1) may, in embodiments, be selected from the wavelength range of 615-645 nm. Further, in embodiments, the first luminescent material light 211 may comprise one or more emission bands having (respective) first full width half maxima (FWHM1) selected from the range of up to 40 nm. Moreover, in embodiments, the first luminescent material 210 may comprise a luminescent material of the type MxM’2-2xAX6 doped with tetravalent manganese. Especially, in embodiments, M may comprise an alkaline earth cation. Further, in embodiments, M’ may comprise an alkaline cation, and x may be in the range of 0-1. Yet further, in embodiments, A may comprise a tetravalent cation. Further, in embodiments, X may comprise a monovalent anion, at least comprising fluorine. In embodiments, the second light generating device 120 may comprise a second solid state light source 20 configured to generate second light source light 21. Moreover, in embodiments, the second light generating device 120 may be configured to generate second device light 121. The second device light 121 may, in embodiments, have in the visible wavelength range a second spectral power distribution with an emission band having a second centroid wavelength (λc2). Especially, in embodiments, the second centroid wavelength (λc2) may be selected from the wavelength range of 605-655 nm. Additionally or 2023PF80226 42 alternatively, in embodiments, the second spectral power distribution may have a second full width half maximum (FWHM2) selected from the range of up to 40 nm. Further, in embodiments, the light generating system 1000 may be configured such that the first spectral power distribution and the second spectral power distribution may at least partly overlap. Additionally or alternatively, in embodiments, the light generating system 1000 may be configured such that |λc1-λc2|≤10 nm. Additionally or alternatively, in embodiments, the light generating system 1000 may be configured such that in an operational mode of the light generating system 1000 the system light 1001 may comprise (one or more of) (i) the first luminescent material light 211 and the (ii) second device light 121. As depicted in Fig.1A subfigure I the luminescent material arrangement 2000 may thus be configured downstream of the first solid state light source 10 (while not downstream of the second solid state light source 20, especially the second light generatingdevice 120). In embodiments, the luminescent material arrangement 2000 may be configuredin (direct) physical contact with the first solid state light source 10. In such embodiments, a first distance d1 (defined as a shortest distance between top surface of the first solid state light source 10 and a first surface of the luminescent material arrangement 2000, especiallythe first luminescent material 210) may be essentially zero. However, in other embodiments,such as depicted in Fig.1A subfigure IV the luminescent material arrangement 2000 may be configured remote from the first solid state light source 10, such that d1 may be selected from the range of 0-25 cm. Further, in embodiments such a depicted in Fig 1A subfigures I and IV, the second light generating device 120 may be a direct-emitting light emitting diode. In such embodiments, the second device light 121 may essentially be second light source light 21. Especially, in embodiments, at least 90% of the second device light 121 may be direct- emitting LED light. Additionally or alternatively, in embodiments, at least 90% of the first device light 111 may be first luminescent material light 211. Hence, most of the first light source light 11 may be converted into first luminescent material light 211 by the first luminescent material 210. In specific embodiments, the first luminescent material 210 (comprising a tetravalent manganese based narrow-band emitter) may comprise one or more of (K,Rb)2SiF6:Mn4+and K2(Si,Ti)F6:Mn4+. Especially, in embodiments, the tetravalent manganese based narrow-band emitter especially may comprise K2SiF6:Mn4+. As depicted in Fig.1A subfigure IV, in embodiments, the luminescent material arrangement 2000 may (also) comprise a second luminescent material 220. In embodiments, the second luminescent material 220 may be configured downstream of the 2023PF80226 43 first solid state light source 10. Additionally, in embodiments, the second luminescent material 220 may be configured to convert at least part of the first light source light 11 into second luminescent material light 221. The second luminescent material light 221 may have in the visible wavelength range a (third) spectral power distribution having a third centroid wavelength (λc3). In embodiments, the third centroid wavelength (λc3) may be selected from the wavelength range of 500-590 nm. Hence, in embodiments, in an operational mode of the light generating system 1000 the system light 1001 may comprise (i) the first luminescent material light 211, the (ii) second device light 121, and (iii) (optionally unconverted the first light source light 11, (iv)) the second luminescent material light 221. Further, in embodiments, the second luminescent material 220 and optionally the fourth luminescent material 240 (see also further below) may comprise a luminescent material of the type A3B5O12:Ce3+. Especially, in embodiments, A may comprise one or more of Y, La, Gd, Tb and Lu. Further, in embodiments, B may comprise one or more of Al, Ga, In, and Sc. As depicted in Fig.1A subfigure II and III, the luminescent material arrangement 2000 may also be configured downstream of both the first solid state light source 10 and the second solid state light source 20. In such embodiments, the first light generating device 110 may comprise the first solid state light source 10 and the first luminescent material 210, whereas the second light generating device 120 may essentially be the second solid state light source 20 (thus not including a luminescent element 200). For example, in such embodiments, the luminescent material arrangement 2000 may comprise a luminescent element 200 (comprising the first luminescent material 210 and optionally the second luminescent material 220) selected from the group comprising a luminescent layer or body (as depicted in subfigure II), and an encapsulant (as depicted in subfigure III). In further embodiments, such as depicted in Fig.1B, the light generating system 1000 may comprise a third light generating device 130 configured to provide third device light 131. The third device light 131 may, in embodiments, have a peak emissionwavelength selected from the wavelength range of 435-470 nm. In embodiments, the thirdlight generating device 130 may comprise a third solid state light source 30 configured to generate third light source light 31. Especially, in embodiments, the third light generating device 130 may be a direct-emitting light-emitting diode. In such embodiments, the third device light 131 may be third light source light 31. Furthermore, in such embodiments, the third device light is especially blue light. 2023PF80226 44 Similarly to the embodiments described above, here the luminescent material arrangement 2000 may be configured downstream of the first solid state light source 10, while not being configured downstream of the second solid state light source 20 and the third solid state light source 30, as depicted in Fig.1B subfigure I. As depicted here, the luminescent material arrangement 2000 may be configured in (direct) physical contact with the first solid state light source 10, i.e., at a distance d1 equal to zero. Alternatively, analogous to the embodiment depicted in Fig.1A subfigure IV, here the luminescent material arrangement 2000 may also be configured remote from the first solid state light source 10, e.g., at a distance d1 selected from the range of 0-25 cm. Additionally or alternatively, in embodiments, the light generating system 1000 may comprise a fourth light generating device 140 configured to provide fourth device light 141. The fourth device light 141 may, in embodiments, have a wavelength selected from the range of 500-580 nm. Further, in embodiments, the fourth light generating device 140 may comprise a fourth solid state light source 40 configured to generate fourth light source light 41. Especially, in embodiments, the fourth light generating device 140 may be a phosphor-converted light-emitting diode. Therefore, in embodiments, the fourth light generating device 140 may especially comprise a fourth luminescent material 240 configured to convert at least part of the fourth light source light 41 into fourth luminescent material light 241. In such embodiments, the fourth device light 141 may comprise at least part of the fourth luminescent material light 241. Furthermore, in such embodiments, the fourth device light is especially green-yellow light. Further, in some embodiments, the second luminescent material 220 and the fourth luminescent material 240 may be different types of luminescentmaterial. However, in other embodiments, the second luminescent material 220 and thefourth luminescent material 240 may be essentially the same (type of) luminescent material (see also above). As depicted in Fig.1B subfigure II, embodiments, the luminescent material arrangement 2000 may be configured downstream of the first solid state light source 10 and (one or more of) the second solid state light source 20 and the fourth solid state light source 40. For example, in such embodiments, the luminescent material arrangement 2000 may comprise a luminescent element 200 (comprising the first luminescent material 210 and optionally the second luminescent material 220 and / or the fourth luminescent material 240) selected from the group comprising a luminescent layer or body (as depicted in subfigure II), and an encapsulant (not depicted). 2023PF80226 45 In specific embodiments, such as depicted in Fig.1C, the light generating system may comprise 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. In such embodiments, the luminescent material arrangement 2000 may comprise the first luminescent material 210 and the fourth luminescent material 240 (and optionally the second luminescent material 220). As depicted here, the luminescent material arrangement 2000 may especially comprise (i) a luminescent element 200 configured downstream of the first solid state light source 10 and comprising at least the first luminescent material 210, and (ii) another luminescent element 200 configured downstream of the fourth solid state light source 40 and comprising at least the fourth luminescent material 240. Also here, in embodiments, different luminescent elements may be possible, such as an encapsulant or a luminescent layer comprising the luminescent materials. Herein reference 700 may refer to a support configured to support the light generating devices 100 (and the luminescent material arrangement 2000). Especially, in embodiments, the light generating system 1000 may comprise a support 700 configured to support the first light generating device 110, the second light generating device 120, and (optionally) one or more of the third light generating device 130 and the fourth light generating device 140. In some embodiments, the light generating system may comprise a LED strip comprising the support, such as e.g. depicted in Fig.1C. In embodiments, the light generating system 1000 may further comprise a control system 300. The control system 300 may be configured to individually control the light generating devices 100. Especially, in embodiments, the control system 300 may be configured to control the first light generating device 110 and second light generating device 120 while maintaining a fixed color point of the system light 1001. Additionally or alternatively, in embodiments, the control system 300 may be configured to control the first light generating device 110 and second light generating device 120 while maintaining a fixed correlated color temperature of the system light 1001. Figs.2 schematically depict some further embodiments of the light generating system 1000. As depicted in Fig.2A, the light generating system 1000 may comprise a Chip- on-Board device 410. The Chip-on-Board device 410 may, in embodiments, comprise the support 700 configured to support one or more first light generating devices 110 and one or more second light generating devices 120. Furthermore, in embodiments, the Chip-on-Board device 410 may comprise the luminescent material arrangement 2000 configured downstream of the first light generating device 110 and the second light generating device 120. As 2023PF80226 46 depicted here, in embodiments, the luminescent material arrangement 2000 may comprise a luminescent element 200 (such as a luminescent layer) comprising first luminescent material 210 and (optionally) the second luminescent material 220. Additionally, in embodiments, the Chip-on-Board device 410 may comprise one or more of the third light generating device 130 and the fourth light generating device 140. Alternatively, as depicted in Fig.2B, the light generating system 1000 may comprise a LED filament 420. The LED filament 420 may, in embodiments, comprise the support 700 configured to support one or more first light generating devices 110 and one or more second light generating devices 120. Furthermore, in embodiments, the LED filament 420 may comprise the luminescent material arrangement 2000 configured downstream of the first light generating device 110 and the second light generating device 120. As depicted here, in embodiments, the luminescent material arrangement 2000 may comprise a luminescent element 200 (such as an encapsulant) comprising first luminescent material 210 and (optionally) the second luminescent material 220. Additionally, in embodiments, the LED filament 420 may comprise one or more of the third light generating device 130 and the fourth light generating device 140. As depicted in Fig.2C, in embodiments, the light generating system 1000 may further comprise an optical sensor 310. The optical sensor 310 may be configured to sense one or more of (i) the first device light 111 and the system light 1001, and generate a related optical sensor signal. In embodiments, the control system 300 may be configured to individually control the light generating devices 100, especially at least the first light generating device 110 and / or the second light generating device 120, in dependence of the optical sensor signal and a predefined radiant flux-time relation. Alternatively, in embodiments, the control system 300 may be configured to individually control the light generating devices 100, especially at least the first light generating device 110 and / or the second light generating device 120, in dependence of the optical sensor signal and a predefined (luminous) intensity-time relation. 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. Figs.3A-B schematically depict some spectral power distributions of elements in the light generating system 1000. Especially, Fig.3A depicts embodiments of the centroid wavelength range of the second device light 121 and the excitation spectrum of the first luminescent material 210. In embodiments, the first centroid wavelength (λc1) and the second 2023PF80226 47 centroid wavelength (λc2) may be selected relatively close to each other. Especially, in embodiments, |λc1-λc2|≤5 nm. As can be derived from the spectra, the first luminescent material light 211 and the second device light 121 may especially have overlapping centroid wavelengths, thus resulting in a reduced shift in color point should the first luminescent material 210 deter over time. In particular, in embodiments, the first centroid wavelength (λc1) may be selected from the wavelength range of 625-635 nm. Moreover, in embodiments, the second centroid wavelength (λc1) may be selected from the wavelength range of 620-640 nm. Fig.3B depicts a spectrum of white system light 1001 in a light generating system 1000 comprising 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. Fig.3B especially depicts a system light 1001 output spectrum, i.e., a combination of the emission and excitation spectra of the first luminescent material light 211, the second device light 121, the third device light 131, and the fourth luminescent material light 241. The spectrum relates to white system light 1001 with a CCT of 4000 K and composed of first luminescent material light having a first centroid wavelength of λc1=632 nm, second device light having a second centroid wavelength of λc2=632 nm, third device light having a peak emission wavelength of 455 nm, and fourth luminescent material light having a fourth centroid wavelength λc4 of 550 nm. However, combinations of different wavelengths (such as selected from the ranges indicated above) may be possible as well. Referring to Figs.3a-3b, the characteristic narrow band emissions of ((some) luminescent materials doped with) Mn4+may include a plurality of relatively narrow bands (sometimes also indicated as “line emissions”). Each of these narrow bands, centered about 632 nm, may have a FWHM of at maximum 40 nm (at room temperature). Note that some of these narrow bands may partly overlap. Due to this effect, as well as apparatus related resolution aspects, the narrow bands may appear to be broader. However, when measured with enough resolution (at room temperature) and when deconvoluting overlapping bands, the FWHMs will in general be (well) below 540 nm. Further, in embodiments, the system light 1001 may be white light having a correlated color temperature selected from the range of 1700-6500 K and a color rendering index of at least 80. Fig.4 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Fig.4 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a 2023PF80226 48 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, an automotive lighting device, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, an automotive lighting 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. 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 2023PF80226 49 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. 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. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. 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. 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

2023PF80226 50 CLAIMS:

1. A light generating system (1000), configured to provide system light (1001);wherein the light generating system (1000) comprises (i) a first light generating device (110), (ii) a second light generating device (120), and (iii) a luminescent material arrangement (2000); wherein:- the first light generating device (110) comprises a first solid state light source(10) configured to generate first light source light (11) having a wavelength selected from the wavelength range of 430-490 nm; wherein the first light generating device (110) is configured to generate first device light (111);- the luminescent material arrangement (2000) comprises a first luminescentmaterial (210), configured downstream of the first light source (10), and configured to convert at least part of the first light source light (11) received by the first luminescent material (210) into first luminescent material light (211) having in the visible wavelength range a first spectral power distribution having a first centroid wavelength (λc1); wherein the first centroid wavelength (λc1) is selected from the wavelength range of 615-645 nm; wherein the first luminescent material light (211) comprises one or more emission bands having first full width half maxima(FWHM1) selected from the range of up to 40 nm; wherein the first luminescent material (210) comprises a luminescent material of the type MxM’2-2xAX6doped with tetravalent manganese, wherein M comprises an alkaline earth cation, wherein M’ comprises an alkaline cation, and x is in the range of 0-1, wherein A comprises a tetravalent cation, wherein X comprises a monovalent anion, at least comprising fluorine;- the second light generating device (120) comprises a second solid state lightsource (20); wherein the second light generating device (120) is configured to generate second device light (121) having in the visible wavelength range a second spectral power distribution with an emission band having (a) a second centroid wavelength (λc2) selected from the wavelength range of 605-655 nm, and (b) a second full width half maximum (FWHM2) selected from the range of up to 40 nm; and- the light generating system (1000) is configured such that (a) the first spectralpower distribution and the second spectral power distribution at least partly overlap, whereinthe overlap is larger than 50 %, (b) |λc1-λc2|≤10 nm; and (c) in an operational mode of the2023PF80226 51 light generating system (1000) the system light (1001) comprises (i) the first luminescent material light (211) and the (ii) second device light (121).

2. The light generating system (1000) according to claim 1, wherein the secondlight generating device (120) is a direct-emitting light emitting diode.

3. The light generating system (1000) according to any one of the precedingclaims, wherein |λc1-λc2|≤5 nm; wherein the first centroid wavelength (λc1) is selected from the wavelength range of 625-635 nm; and wherein the second centroid wavelength (λc1) is selected from the wavelength range of 620-640 nm.

4. The light generating system (1000) according to any one of the precedingclaims, wherein the first luminescent material (210) comprises one or more of (K,Rb)2SiF6:Mn4+and K2(Si,Ti)F6:Mn4+.

5. The light generating system (1000) according to any one of the precedingclaims, wherein the luminescent material arrangement (2000) comprises a second luminescent material (220), wherein the second luminescent material (220) (a) is configured downstream of the first solid state light source (10) and (b) is configured to convert at least part of the first light source light (11) into second luminescent material light (221) having in the visible wavelength range a spectral power distribution having a third centroid wavelength (λc3) selected from the wavelength range of 500-590 nm; wherein in an operational mode of the light generating system (1000) the system light (1001) comprises (i) the first luminescent material light (211), the (ii) second device light (121);, and (iii) the second luminescent material light.

6. The light generating system (1000) according to any one of the precedingclaims, further comprising:- a third light generating device (130) configured to provide third device light(131) having a peak emission wavelength selected from the wavelength range of 435-470 nm; wherein the third light generating device (130) comprises a third solid state light source (30) configured to generate third light source light (31); and wherein the third light2023PF80226 52 generating device (130) is a direct-emitting light-emitting diode and wherein the third device light (131) is third light source light (31); and wherein the third device light is blue light; and- a fourth light generating device (140) configured to provide fourth device light(141) having a wavelength selected from the range of 500-580 nm; wherein the fourth lightgenerating device (140) comprises a fourth solid state light source (40) configured togenerate fourth light source light (41); wherein the fourth light generating device (140) is a phosphor-converted light-emitting diode comprising a fourth luminescent material (240) configured to convert at least part of the fourth light source light (41) into fourth luminescent material light (241), wherein the fourth device light (141) comprises at least part of the fourth luminescent material light (241); and wherein the fourth device light is green-yellow light.

7. The light generating system (1000) according to any one of the precedingclaims 5-6, wherein the second luminescent material (220) and optionally the fourth luminescent material (240) comprises a luminescent material of the type A3B5O12:Ce3+, wherein A comprises one or more of Y, La, Gd, Tb and Lu, and wherein B comprises one or more of Al, Ga, In, and Sc.

8. The light generating system (1000) according to any one of the precedingclaims 5-7, wherein the system light (1001) is white light having a correlated color temperature selected from the range of 1700-6500 K and a color rendering index of at least 80.

9. The light generating system (1000) according to any one of the precedingclaims, wherein at least 90% of the first device light (111) is first luminescent material light (211) and at least 90% of the second device light (121) is direct-emitting LED light.

10. The light generating system (1000) according to any one of the precedingclaims, further comprising a control system (300), wherein the control system (300) is configured to individually control the light generating devices (110,120,...); wherein the control system (300) is configured to control the first light generating device (110) and second light generating device (120) while maintaining one or more of (i) a fixed color point of the system light (1001), and (ii) a fixed correlated color temperature of the system light (1001).2023PF80226 5311. The light generating system (1000) according to claim 10, further comprisingan optical sensor (310) configured to sense one or more of (i) the first device light (111) and the system light (1001), and generate a related optical sensor signal, wherein the control system (300) is configured to individually control one or more of the light generating devices (110,120,...) in dependence of the optical sensor signal.

12. The light generating system (1000) according to any one of claims, whereinthe first light generating device (110) comprises a phosphor converted light-emitting diode comprising the first luminescent material (210) and the second luminescent material (220) according to claim 5 or claim 7; wherein the light generating system (1000) further comprises a support (700) configured to support the first light generating device (110), the second light generating device (120), and one or more of the third light generating device (130) and the fourth light generating device (140) as defined in claim 6.

13. The light generating system (1000) according to claim 12, comprising a LEDstrip (430), comprising the support (700).

14. The light generating system (1000) according to any one of the precedingclaims, wherein the light generating system (1000) comprises a LED filament (420), wherein the luminescent material arrangement (2000) is configured downstream of the first light generating device (110) and the second light generating device (120); wherein the luminescent material arrangement (2000) further comprises the second luminescent material (220) according to claim 5 or claim 7.

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

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