Lighting device with an improved performance while mimicking sunlight
The invention provides a light generating system ( 1000 ) comprising (a) a plurality of sets ( 150 ) of light generating devices ( 100 ) and (b) a luminescent material ( 200 ), wherein: the light generating devices ( 100 ) are configured in an array ( 40 ); the light generating devices ( 100 ) are configured to generate device light ( 101 ); wherein the light generating devices ( 100 ) comprise solid state light sources; the plurality of sets ( 150 ) of light generating devices ( 100 ) comprises at least three sets ( 50 ) of light generating devices ( 100 ), wherein the light generating devices ( 100 ) of different sets mutually differ in peak wavelengths (λp) of the device light ( 101 ), wherein at least one set ( 50 ) of light generating devices ( 100 ) is configured to generate device light ( 111 ) having a peak wavelength (λpb) in the blue wavelength range, wherein at least two different sets ( 50 ) of light generating devices ( 100 ) are configured to generate device light ( 101 ) comprising UV radiation with at least two different peak wavelengths (λpu) in the UV wavelength range; and wherein the difference between the at least two different peak wavelengths (λpu) of the device light ( 101 ) is at least 30 nm; the luminescent material ( 200 ) is configured downstream of the array ( 40 ) of light generating devices ( 100 ); wherein the luminescent material ( 200 ) is configured to convert part of the device light ( 101 ) into luminescent material light ( 201 ); wherein at least 80% of a radiant flux of the luminescent material light ( 201 ) is due to conversion of the device light ( 111 ) having the peak wavelength (λpb) in the blue wavelength range; and the light generating devices ( 100 ) and the luminescent material ( 200 ) are configured such that at least part of the device light ( 101 ) comprising UV radiation with at least two different peak wavelengths (λpu) in the UV wavelength range is transmitted by the luminescent material ( 200 ).
1 . A light generating system comprising (a) a plurality of sets of light generating devices and (b) a luminescent material, wherein:
the light generating devices are configured in an array; the light generating devices are configured to generate device light; wherein the light generating devices comprise solid state light sources;
the plurality of sets of light generating devices comprises at least three sets of light generating devices, wherein the light generating devices of different sets mutually differ in peak wavelengths of the device light, wherein at least one set of light generating devices is configured to generate device light having a peak wavelength in the blue wavelength range of 420-495 nm, wherein at least two different sets of light generating devices are configured to generate device light comprising UV radiation with at least two different peak wavelengths in the UV wavelength range of 100-380 nm; and wherein the difference between the at least two different peak wavelengths of the device light is at least 30 nm;
the luminescent material is configured downstream of the array of light generating devices; wherein the luminescent material is configured to convert part of the device light into luminescent material light; wherein at least 80% of a radiant flux of the luminescent material light is due to conversion of the device light having the peak wavelength in the blue wavelength range;
the light generating devices and the luminescent material are configured such that at least part of the device light comprising the UV radiation with the at least two different peak wavelengths in the UV wavelength range of 100-380 nm is transmitted by the luminescent material; and
the luminescent material comprises (a) a luminescent material of the type A 3 B 5 O 12 :Ce, 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, and (b) a luminescent material of the type M′ x M 2-2x AX 6 doped with tetravalent manganese, wherein M′ comprises an alkaline earth cation, wherein M comprises a 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.
2 . The light generating system according to claim 1 , wherein the peak wavelength in the blue wavelength range is selected at a wavelength where an excitation intensity is at least 70% of an excitation maximum of the luminescent material in the blue wavelength range.
3 . The light generating system according to claim 1 , wherein the luminescent material comprises different excitation intensities at at least two different peak wavelengths; wherein at least two different peak wavelengths of the light generating devices of at least two sets of light generating devices are selected at wavelengths where excitation intensities are within the range of up to a maximum of 30% of an excitation intensity of an adjacent excitation maximum of the luminescent material light; and wherein the peak wavelength in the blue wavelength range is selected at a wavelength where an excitation intensity is at least 80% of an excitation maximum of the luminescent material in the blue wavelength range.
4 . The light generating system according to claim 1 , wherein the array comprises a core array part including at least 50% of a total number of the light generating devices and a peripheral array part including less than 50% of the total number of the light generating devices, wherein a majority of the light generating devices for which peak wavelength of their device light the luminescent material has a relatively lower excitation intensity are configured in the peripheral array part, and wherein a majority of the light generating devices for which peak wavelength of their device light the luminescent material has a relatively higher excitation intensity are configured in the core array part.
5 . The light generating system according to claim 1 , wherein the light generating devices are homogeneously distributed over the array.
6 . The light generating system according to claim 1 , comprising n sets of light generating devices, wherein the n sets of light generating devices comprise k different sets of light generating devices configured to generate device light comprising UV radiation with k different peak wavelengths in the UV wavelength range; wherein n≥3; wherein 2≤k≤n−1; wherein the luminescent material comprises excitation intensities f k for the k different peak wavelengths, wherein the lower the excitation intensity f k , the more peripheral the light generating devices are configured.
7 . The light generating system according to claim 6 , wherein k≥3, wherein each of the different peak wavelengths are selected from the group comprising UV-A radiation in the wavelength range of 315-380 nm, UV-B radiation in the wavelength range of 280-315 nm, Near UV-C radiation in the wavelength range of 230-280 nm, and Far UV-C radiation in the wavelength range of 190-230 nm.
8 . The light generating system according to claim 1 , wherein the plurality of sets of light generating devices further comprises at least one set configured to generate device light having a peak wavelength in the violet wavelength range of 380-420 nm.
9 . The light generating system according to claim 1 , wherein the at least two different sets of light generating devices are configured to generate device light comprising UV radiation selected from the group comprising UV-A radiation in the wavelength range of 315-380 nm, UV-B radiation in the wavelength range of 280-315 nm, Near UV-C radiation in the wavelength range of 230-280 nm, and Far UV-C radiation in the wavelength range of 190-230 nm.
10 . The light generating system according to claim 1 , wherein the luminescent material comprises a luminescent material of the type A 3 B 5 O 12 :Ce, wherein A comprises one or more of Y and Lu, and wherein B comprises one or more of Al, Ga, In and Sc, and a luminescent material of the type M 2 AX 6 doped with tetravalent manganese, wherein M comprises a cation, wherein A comprises a tetravalent cation, wherein X comprises a monovalent anion, at least comprising fluorine.
11 . The light generating system according to claim 1 , wherein the plurality of sets of light generating devices are configured in series.
12 . The light generating system according to claim 1 , further comprising a control system, wherein two or more of the at least two sets light generating devices are individually controllable by a control system, wherein at least one or more sets of the at least two individually controllable sets of light generating devices is configured to generate device light having a peak wavelength in the blue wavelength range.
13 . The light generating system according to claim 1 , comprising:
a LED filament, wherein the LED filament comprises the array of light generating devices; wherein the light generating devices of the at least two different sets of light generating devices configured to generate device light comprising UV radiation are configured at one or both end parts of the LED filament; or
a chip-on-board light generating device, wherein the chip-on-board light generating device comprises the plurality of sets of light generating devices; wherein the light generating system further comprises a luminescent layer comprising the luminescent material configured downstream of the chip-on-board light generating device.
14 . The light generating system according to claim 1 , wherein the luminescent material has a luminescent material surface, wherein the radiant fluxes of the light generating devices are selected such that a radiant flux of the luminescent material light over 75-99% of the luminescent material surface varies within a range of +/−15% relative to an average radiant flux over the luminescent material surface.
15 . A lighting device selected from the group of a lamp, a luminaire, and an optical wireless communication device, comprising the light generating system according to claim 1 .