HIGH-INTENSITY LIGHT SOURCE WITH HIGH CRI

Abstract

The invention provides a light generating device (1000), wherein: (I) the light generating device (1000) comprises: (a) a first light source (110) configured to generate first light source light (111) having a first light source light spectral power distribution, wherein the first light source (110) comprises a first laser light source (10) configured to generate first laser light source light (11); (b) a first luminescent material (210) configured to convert at least part of the first light source light (111) into first luminescent material light (211) having a first luminescent material spectral power distribution having an emission at one or more wavelengths selected from the wavelength range of 590-780 nm, wherein the first luminescent material (210) is configured in an optical resonator (230); (II) the first light source (110) and the first luminescent material (210) are configured to generate first luminescent material laser light (1211) having a first luminescent material laser light spectral power distribution comprising at least part of the first luminescent material light (211); (III) the first light source light spectral power distribution and the first luminescent material laser light spectral power distribution mutually differ; and (IV) the light generating device (1000) is configured to generate in one or more operational modes white device light (1001) comprising the first luminescent material laser light (1211).

Claims

1. A light generating device, wherein: the light generating device comprises: (a) a first light source configured to generate first light source light having a first light source light spectral power distribution, wherein the first light source comprises a first laser light source configured to generate first laser light source light; (b) a first luminescent material configured to convert at least part of the first light source light into first luminescent material light having a first luminescent material spectral power distribution having an emission at one or more wavelengths selected from the wavelength range of 590-780 nm, wherein the first luminescent material is configured in an optical resonator; (c) a second light source configured to generate second light source light having a second light source light spectral power distribution, wherein the second light source comprises a second laser light source configured to generate second laser light source light; and (d) a second luminescent material configured to convert at least part of one or more of (i) the first laser light source light and (ii) the second laser light source light to provide second luminescent material light; the first light source and the first luminescent material are configured to generate first luminescent material laser light having a first luminescent material laser light spectral power distribution comprising at least part of the first luminescent material light; the first light source light spectral power distribution and the first luminescent material laser light spectral power distribution mutually differ; the light generating device is configured to generate in one or more operational modes white device light comprising the first luminescent material laser light and the second luminescent material light; and wherein the second luminescent material comprises (Y.sub.x1-x2-x3A.sub.x2Ce.sub.x3).sub.3(Al.sub.y1-y2B.sub.y2).sub.5O.sub.12, wherein x1+x2+x3=1, wherein x3>0, wherein 0<x2+x3≤0.2, wherein y1+y2=1, wherein 0≤y2≤0.2, wherein A comprises one or more elements selected from the group consisting of lanthanides and scandium, and wherein B comprises one or more elements selected from the group consisting of Ga and In, wherein at maximum 10% of Al—O may be replaced by Si—N.

2. The light generating device according to claim 1, wherein the first luminescent material comprises an inorganic material doped with a rare earth ion, and wherein the optical resonator is defined by two wavelength dependent mirrors.

3. The light generating device according to claim 1, wherein the first luminescent material comprises a Pr.sup.3+ doped aluminate.

4. The light generating device according to claim 1, wherein the first light source and the first luminescent material, and optional first optics, are configured to generate first luminescent material laser light having a peak wavelength within the wavelength range of 618-650 nm.

5. The light generating device according to claim 1, wherein the first light source and the first luminescent material, and optional first optics, are configured to generate first luminescent material laser light having a dominant wavelength within the wavelength range of 618-632 nm.

6. The light generating device according to claim 1, wherein the first light source is configured to generate blue first light source light.

7. The light generating device according to claim 6, wherein the first luminescent material is configured to absorb part of the first light source light, and wherein the light generating device is configured to generate in one or more operational modes white device light further comprising the first light source light.

8. The light generating device according to claim 6, comprising one or more first light sources configured to generate the first light source light, wherein: the one or more first light sources, the first luminescent material and optional second optics are configured to generate part of the first light source light bypassing the first luminescent material; and the light generating device is configured to generate in one or more operational modes white device light further comprising the first light source light that bypasses the first luminescent materiality.

9. The light generating device according to claim 1, wherein the first light source light spectral power distribution, the second light source light spectral power distribution, and the first luminescent material laser light spectral power distribution mutually differ; wherein the second light source is configured to generate second light source light having the second light source light spectral power distribution with one or more wavelengths in the green and yellow wavelength range; and wherein the light generating device is configured to generate in one or more operational modes white device light further comprising the first light source light and the second light source light.

10. The light generating device according to claim 1, wherein the second light source is configured to generate blue second light source light.

11. The light generating device according to claim 10, wherein the second luminescent material is configured to convert at least part of the first laser light source light to provide second luminescent material light.

12. The light generating device according to claim 10, wherein: the first laser light source and the first luminescent material are configured to generate first luminescent material laser light; the first laser light source and the second luminescent material are configured to generate second luminescent material light; and the light generating device may be configured to generate in one or more operational modes white device light comprising the first laser light source light, the first luminescent material laser light, and the second luminescent material light.

13. The light generating device according to claim 10, comprising a plurality of first laser light sources configured to generate blue laser light, wherein: a first set of one of more first laser light sources are configured to generate blue first laser light that bypasses the first luminescent material and the second luminescent material; a second set of one of more first laser light sources are configured to generate blue first laser light that irradiates the first luminescent material but bypasses the second luminescent material; a third set of one of more first laser light sources are configured to generate blue first laser light that bypasses the first luminescent material but irradiates the second luminescent material; the light generating device further comprises a control system configured to control the plurality of first laser light sources.

14. The light generating device according to claim 1, wherein the light generating device is configured to generate in one or more operational modes white device light having a CRI of at least 85 and a CCT of at maximum 3500 K.

15. A lamp or a luminaire comprising the light generating device according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0114] 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:

[0115] FIGS. 1a-1g schematically depict some possible embodiments;

[0116] FIG. 2 shows a possible emission spectrum of a light generating device; and

[0117] FIG. 3 schematically depicts embodiments of a luminaire and a lamp.

[0118] The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0119] FIG. 1 schematically depicts an embodiment of a light generating device 1000. The light generating device 1000 comprises a first light source 110 configured to generate first light source light 111. The first light source light 111 has a first light source light spectral power distribution. Especially, the first light source 110 comprises a first laser light source 10 configured to generate first laser light source light 11. Optics 310 may be applied to provide a collimated beam of first laser light source light. The first laser light source 10 is especially a solid state laser, like a diode laser. The light generating device 1000 further comprises a first luminescent material 210 configured to convert at least part of the first light source light 111 into first luminescent material light 211 having a first luminescent material spectral power distribution having an emission at one or more wavelengths selected from the wavelength range of 590-780 nm.

[0120] Especially, the first light source 110 and the first luminescent material 210 are configured to generate first luminescent material laser light 1211 having a first luminescent material laser light spectral power distribution comprising at least part of the first luminescent material light 211. To this end, the first luminescent material 210 may especially be provided as ceramic body or comprised by a ceramic bod, or as single crystal or comprised by a single crystal. Further, the luminescent material, especially the luminescent body, may be configured between two optical elements 231,232, especially (wavelength-dependent) mirrors, to provide an optical cavity for the desired laser wavelength(s). Hence, especially the luminescent material 210 may be configured in an optical cavity 230.

[0121] The first light source light spectral power distribution and the first luminescent material laser light spectral power distribution mutually differ.

[0122] Especially, first luminescent material light 211 or more especially the first luminescent material laser light 1211 may be orange or red, especially red. Hence, the first luminescent material laser light 1211 may have intensity at one or more wavelengths in the orange and/or red, especially at least within the range of 618-650 nm, such as 618-632 nm.

[0123] Hence, in embodiments the first light source 110 and the first luminescent material 210, and optional first optics (see below), are configured to generate first luminescent material laser light 1211 having a peak wavelength within the wavelength range of 618-650 nm, more especially a peak wavelength within the wavelength range of 618-632 nm.

[0124] Especially, the first luminescent material light may have a dominant wavelength in the 618-650 nm range, especially in the wavelength range of 618-632 nm.

[0125] In embodiments, the first luminescent material 210 may comprise an inorganic material doped with a (trivalent) rare earth ion (able to convert one or more of blue light and UV radiation into visible light). For instance, in embodiments the first luminescent material 210 comprises Pr.sup.3+. Especially, in embodiments the first luminescent material 210 may comprise a Pr.sup.3+ doped aluminate. For instance with such luminescent material, especially the herein described aluminate, the dominant wavelength may be in the 618-632 nm range, see also FIG. 2.

[0126] In specific embodiments, the first light source 110 is configured to generate blue first light source light 111. All this blue first light source light 111 may be converted, or part may be use for generating e.g. white device light 1001. In FIG. 1, the latter variant is schematically depicted.

[0127] In one or more operational modes of the light generating device 1000 the light generating device 1000 may be configured to generate white device light 1001 comprising the first luminescent material laser light 1211. To this end, the first luminescent material laser light 1211 and the (remaining) blue first light source light maybe applied. In addition, yellow and/or green light may have to be provided.

[0128] FIG. 1a schematically depicts an embodiment wherein e.g. a second light source 120 may be applied. Hence, in embodiments a second light source 120 configured to generate second light source light 121 having a second light source light spectral power distribution may be applied, wherein in embodiments the second light source 120 comprises a second laser light source 20 configured to generate second laser light source light 21. Hence, the second light source light 121 may essentially consist of the second laser light source light 21.

[0129] Hence, the light generating device 1000 the light generating device 1000 may especially be configured to generate, in one or more operational modes (of the light generating device 1000), white device light 1001 comprising the first light source light 111, the first luminescent material laser light 1211 and (optionally) the second light source light 121). More especially, in embodiments the device light 1001 may in one or more operational modes the first luminescent material laser light 1211 and the (remaining) blue first light source light 111 and second laser light 21.

[0130] Further, the light generating device 1000 further comprises a control system 300 configured to control the plurality of first laser light sources 10 or may be functionally coupled to such control system 300.

[0131] FIG. 1b schematically depicts a variant, wherein the one or more first light sources 110, (the first luminescent material 210,) and (optional) second optics 432 are configured to generate part of the first light source light 111 bypassing the first luminescent material 210. This fist light source light may thus essentially comprise first laser light 11. Optics 432 may be beam splitters or mirrors.

[0132] Further, by way of example optional first optics 431 are depicted. Such optional first optics 431 may be used as optical filter to filter out undesired wavelengths. In this way, e.g. a very narrow wavelength region for laser wavelength maybe chosen. For instance, referring to trivalent praseodymium .sup.3P.sub.0.fwdarw..sup.3H.sub.6 transition may be selected.

[0133] Hence, in embodiments in one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate white device light 1001 comprising the first light source light 111 that bypasses the first luminescent material 210, the first luminescent material laser light 1211 and (optionally) the second light source light 121.

[0134] FIG. 1c schematically depicts an embodiment similar to the embodiment of FIG. 1a, however, here, the light generating device 1000 comprises a plurality of first light sources 110 configured to generate the first light source light 111. Part of the first light source light can be mixed into the device light 1001 without being into contact with the first luminescent material 210.

[0135] FIGS. 1d and 1e schematically depict embodiments wherein the light generating device 1000 further comprises a second luminescent material 220. The second luminescent material 220 is configured to convert at least part of one or more of (a) the first laser light source light 11 and (b) the optional second light source light, such as in embodiments second laser light source light 21, to provide second luminescent material light 221. In one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate white device light 1001 comprising the first luminescent material light 211 and the second luminescent material light 221. Or, in other words (see also above), the light generating device 1000 is configured to generate white device light 1001 comprising the first luminescent material light 211 and the second luminescent material light 221 in one or more operational modes of the light generating device 1000.

[0136] FIG. 1d shows an embodiment wherein the second luminescent material 220 is configured to convert at least part of the second light source light, especially second laser light source light 21, to provide second luminescent material light 221. Optionally, part of the second light source light 121 may stay unconverted. Hence, in one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate white device light 1001 comprising the first light source light 111 that bypasses the first luminescent material 210, the first luminescent material laser light 1211, and the second light source light 121, and second luminescent material light 221.

[0137] FIG. 1e shows an embodiment wherein the second luminescent material 220 is configured to convert at least part of the first light source light 111, especially first laser light source light 11, to provide the second luminescent material light 221. Hence, in one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate white device light 1001 comprising the first light source light 111 that bypasses the first luminescent material 210, the first luminescent material laser light 1211, and second luminescent material light 221.

[0138] As indicated above, the luminescent material 220 may comprise (y.sub.x1-x2-x3A.sub.x2Ce.sub.x3).sub.3(Al.sub.y1-y2B.sub.y2).sub.5O.sub.12, wherein x1+x2+x3=1, wherein x3>0, wherein 0<x2+x3≤0.2, wherein y1+y2=1, wherein 0≤y2≤0.2, wherein A comprises one or more elements selected from the group consisting of lanthanides and scandium, and wherein B comprises one or more elements selected from the group consisting of Ga and In, wherein at maximum 10% of Al—O may be replaced by Si—N. Especially, x3 is selected from the range of 0.001-0.1, wherein 0<x2+x3≤0.1, and wherein 0≤y2≤0.1.

[0139] FIG. 1f schematically depicts an embodiment wherein essentially a single type of first light source 110 may be applied. Here, the first laser light source 10 and the first luminescent material 210 are configured to generate first luminescent material laser light 1211. Further, the first laser light source 10 and the second luminescent material 220 are configured to generate second luminescent material light 121. Hence, in one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate white device light 1001 comprising the first laser light source light 11, the first luminescent material laser light 1211, and the second luminescent material light 221.

[0140] FIG. 1g schematically depicts an embodiment wherein the light generating system 1000 comprises a first set of one of more first laser light sources 10 are configured to generate blue first laser light 11 that bypasses the first luminescent material 210 and the second luminescent material 220. Further, the light generating system 1000 comprises a second set of one of more first laser light sources 10 are configured to generate blue first laser light 11 that irradiates the first luminescent material 210 but bypasses the second luminescent material 220. Yet further, the light generating system 1000 comprises a third set of one of more first laser light sources 10 are configured to generate blue first laser light 11 that bypasses the first luminescent material 210 but irradiates the second luminescent material 220.

[0141] In specific embodiments the plurality of first laser light sources 10 are configured to generate blue laser light 11.

[0142] In specific embodiments, the control system 300 is configured to control the plurality of first laser light sources 10 (individually).

[0143] Referring e.g. to the embodiments such as schematically depicted in FIGS. 1a, 1b, 1c, and 1d, the second light source 120 may be configured to generate second light source light 121 having a second light source light spectral power distribution, wherein the second light source 120 comprises a second laser light source 20 configured to generate second laser light source light 21. Further, the first light source light spectral power distribution, the second light source light spectral power distribution, and the first luminescent material laser light spectral power distribution mutually differ. Yet further, the second light source 120 is configured to generate second light source light 121 having the second light source light spectral power distribution with one or more wavelengths in the green and yellow wavelength range; and

[0144] Referring to the embodiments schematically depicted in the afore described drawings, in one or more operational modes of the light generating device 1000 the light generating device 1000 is configured to generate the white device light 1001 having a CRI of at least 85 and a CCT of at maximum 3200 K. The optical properties of the device may be controlled by the control system 300. In other operational modes, colored light may be provided, or light with a higher CCT, etc.

[0145] The solid state light sources may be controlled by controlling the power and/or by controlling a pulse width modulation of the power.

[0146] FIG. 2 shows a spectral power distribution of an example of device light comprising a blue laser peak, red laser peaks from Pr.sup.3+, and yellow/green from a garnet luminescent material.

[0147] In below table, some examples are given of combinations of blue, green and red. In examples 1-3, the emission spectra of Pr.sup.3+ in the 580-780 nm range have been chosen of Sr.sub.0.7La.sub.0.3Mg.sub.0.3Al.sub.11.7O.sub.19:Pr.sup.3+ (ASL:Pr) by way of example; though other materials may of course also be possible. In Examples, 4-8, the laser line (LL) has been narrowed to a very specific wavelength. The percentage are the radiometric contributions to the white spectrum (based on Watts).

TABLE-US-00001 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 Ex. 8 CCT (K) 3500 3000 2700 3500 3000 2700 3500 3000 CRI 91 92 90 93 92 91 91 90 R9 92 74 64 75 65 76 60 55 LE (L/W) 277 265 257 349 350 348 334 327 Blue λ.sub.max 470 465 470 465 470 470 465 470 (nm), nm, nm, nm, nm, nm, nm, nm, nm, DWL 470 465 470 465 470 470 465 470 (nm), nm, nm, nm, nm, nm, nm, nm, nm, percentage 16% 9% 8% 16% 15% 11% 15% 14% Green λ.sub.max 547 551 547 543 547 551 543 547 (nm), nm, nm, nm, nm, nm, nm, nm, nm, DWL 571 570 571 568 571 570 568 571 (nm), nm, nm, nm, nm, nm, nm, nm, nm, percentage 54% 51% 46% 66% 65% 51% 64% 63% Red λ.sub.max 645 645 645 620 620 620 628 630 (nm), nm, nm, nm, nm, nm, nm, nm, nm, DWL 624 624 624 620 620 620 628 630 (nm), nm, nm, nm, nm, nm, nm, nm, nm, percentage 30% 40% 46% 18% 20% 20% 21% 23% Red ASL:Pr ASL:Pr ASL:Pr LL 620 LL 620 LL 620 LL 628 LL 630 (580- (580- (580- nm nm nm nm nm 780 nm) 780 nm) 780 nm) Percentage 35% 18% 15% 47% 43% 35% 42% 37% blue relative to B + R

[0148] The percentage blue indicates the blue contribution to the white light and the percentage blue relative to B+R indicates the percentage of blue relative to the contributions of blue and red.

[0149] FIG. 3 schematically depicts an embodiment of a luminaire 2 comprising the light generating device 1000 as described above. Reference 301 indicates a user interface, such as a graphical user interface, which may be functionally coupled with the control system 300 comprised by or functionally coupled to the lighting system 1000. FIG. 3 also schematically depicts an embodiment of lamp 1 comprising the light generating device 1000. The lamp 1 or luminaire 2 may also comprise other elements, like optical elements. For instance, the lamp 1 or luminaire 2 may comprise beam shaping optics, or beam direction optics. In embodiments, the lamp 1 or luminaire 2 may comprise beam shaping elements. In embodiments, the luminaire 2 may comprise louvres, etc.

[0150] Hence, amongst others, herein the application of rare earth doped crystals which can give down converting laser emission in the red region when stimulated by a blue laser is proposed. Part of the blue laser light is then used to pump a cerium doped YAG phosphor and/or alternative phosphor. Combining spontaneous emission light from YAG, stimulated emission from red emitting crystal, and blue emitting laser may provide white light, which may have a CRI higher than 90 at a CCT of e.g. below 3500 K, such as below 3000K, close or on the BBL. In this way the problem with differential aging can be solved.

[0151] The term “plurality” refers to two or more.

[0152] 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%.

[0153] The term “comprise” also includes embodiments wherein the term “comprises” means “consists of”.

[0154] 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”.

[0155] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0156] 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.

[0157] 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.

[0158] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0159] 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”.

[0160] The article “a” or “an” preceding an element does not exclude the presence of a plurality of such elements.

[0161] 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.

[0162] 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.

[0163] 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.

[0164] 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.