High intensity white light source with good uniformity based on a plurality of light sources

Abstract

The invention provides a light generating system (1000) comprising: (i) a first set (1100) comprising n1 first light generating devices (110), (ii) a first optical element (410), and (iii) a luminescent body (200), wherein: the n1 first light generating devices (110) are configured to generate first device light (111); wherein the n1 first light generating devices (110) may be selected from the group of lasers and superluminescent diodes; the first set (1100) comprises k1 first subsets (1115) of each at least one first light generating device (110) of the n1 first light generating devices (110), wherein n13, especially n15, and 2k1n1; the luminescent body (200) is configured to: (i) convert part of the first device light (111) into luminescent material light (211), and (ii) transmit part of the first device light (111); the n1 first light generating devices (110) and the first optical element (410) are configured to provide first beams (115) of first device light (111) to the luminescent body (200), wherein two or more first beams (115) of two or more first light generating devices (110) of the k1 first subsets (1115) have different first angles of incidence (1) relative to a normal to the luminescent body (200); andin an operational mode of the light generating system (1000) a first intensity of the first device light (111) of the k1 first subsets (1115) is dependent upon the first angles of incidence (1).

Claims

1. A light generating system comprising: (i) a first set of light generating devices comprising n1 light generating devices, (ii) a first optical element, and (iii) a luminescent body, wherein: the n1 first light generating devices are configured to generate first device light; wherein the n1 first light generating devices are selected from the group of lasers and super luminescent diodes, and wherein the n1 first light generating devices are configured to generate first device light having a wavelength selected from the range of 380-495 nm; the n1 first light generating devices of the first set of light generating devices are divided into k1 first subsets, wherein n13, and 2k1n1; the luminescent body is configured to: (i) convert part of the first device light into luminescent material light, and (ii) transmit part of the first device light; the n1 first light generating devices and the first optical element are configured to provide first beams of first device light to the luminescent body, wherein two or more first beams of two or more first light generating devices from two or more different first subsets of the k1 first subsets have different first angles of incidence (1) relative to a normal to the luminescent body; in an operational mode of the light generating system a first intensity of the first device light of the k1 first subsets increases with increasing first angle of incidence (1); and wherein in the operational mode a ratio of a highest first intensity (I1,max) and a lowest first intensity (I1,min) of the of the first device light of the k1 first subsets, upstream of the luminescent body is selected from the range of 1.04(I1,max/I1,min)10.

2. The light generating system according to claim 1, wherein in the operational mode at least two of the two or more first beams of two or more first light generating devices of the k1 first subsets have first angles of incidence (1) relative to the normal to the luminescent body differing with a mutual angle () selected from the range of 15-135.

3. The light generating system according to claim 1, wherein the n1 first light generating devices are selected from the group of lasers.

4. The light generating system according to claim 1, wherein the luminescent body has a body height (H1) and a scattering mean free path (Is) for the first device light, wherein 1s>*H1.

5. The light generating system according to claim 1, wherein the luminescent body has a transmission for perpendicularly provided first device light in the range of 5-20%; wherein the luminescent body is configured to convert part of the first device light into luminescent material light having a wavelength in the range of 495-605 nm.

6. The light generating system according to claim 1, further comprising a control system, wherein the k1 first subsets are individually controllable, and wherein the control system is configured to control the k1 first subsets.

7. The light generating system according to claim 1, further comprising a second optical element, wherein the second optical element comprises a lens array with m1 lenslets or collimator element, wherein the m1 lenslet or collimator element are configured downstream of the n1 first light generating devices and upstream of the first optical element, wherein m1=n1.

8. The light generating system according to claim 1, further comprising a second set of light generating devices comprising n2 second light generating devices, wherein: the second light generating devices are configured to generate second device light; the n2 second light generating device of the second set of light generating devices are divided into k2 second subsets, wherein n23 and 2k2n2; the luminescent body has a transmission for perpendicularly provided second device light of at least 65%; the n2 second light generating devices and the first optical element are configured to provide second beams of second device light to the luminescent body, wherein two or more second beams of two or more second light generating devices from two or more different second subsets of the k2 second subsets have different second angles of incidence (2) relative to the normal to the luminescent body; and in an operational mode of the light generating system a second intensity of the second device light of the k2 second subsets is dependent upon the second angles of incidence (2).

9. The light generating system according to claim 8, wherein in the operational mode the second intensity of the second device light of the k2 second subsets decreases with increasing second angle of incidence (2).

10. The light generating system according to claim 9, further comprising a third optical element, wherein the third optical element comprises a beam combiner, wherein the third optical element is configured downstream of the n1 first light generating devices and the n2 second light generating devices, and upstream of the first optical element, and wherein the third optical element is configured to combine the first device light and the second device light.

11. The light generating system according to claim 8, wherein one or more of the following applies: (i) the n1 first light generating devices comprise vertical-cavity surface-emitting lasers, and (ii) the n2 second light generating devices comprise vertical-cavity surface-emitting lasers; and wherein the n2 second light generating devices are configured to provide second device light having a wavelength in the range of 605-780 nm.

12. A light generating device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, and an optical wireless communication device, comprising the light generating system according to claim 1.

13. The light generating device according to claim 12, wherein: the n1 first light generating devices comprise lasers; and the light generating device is configured to generate white light having a CCT selected from the range of 2700-4000 K and having a CRI of at least 80.

14. A light generating system comprising: (i) a first set comprising n1 first light generating devices, (ii) a first optical element, and (iii) a luminescent body, wherein: the n1 first light generating devices are configured to generate first device light; wherein the n1 first light generating devices are selected from the group of lasers and super luminescent diodes, and wherein the n1 first light generating devices are configured to generate first device light having a wavelength selected from the range of 380-495 nm; the first set comprises k1 first subsets of each at least one first light generating device of the n1 first light generating devices, wherein n13, and 2k1n1; the luminescent body is configured to: (i) convert part of the first device light into luminescent material light, and (ii) transmit part of the first device light; the n1 first light generating devices and the first optical element are configured to provide first beams of first device light to the luminescent body, wherein two or more first beams of two or more first light generating devices from two or more different first subsets of the k1 first subsets have different first angles of incidence (1) relative to a normal to the luminescent body; in an operational mode of the light generating system a first intensity of the first device light of the k1 first subsets increases with increasing first angle of incidence (1); wherein the luminescent body has an upstream face, configured in a light receiving relationship with the n1 first light generating devices, and a downstream face from which during the operational mode (a) first device light after transmission through the luminescent body, and (b) luminescent material light, escape, wherein the light generating system is configured to generate system light, wherein in the operational mode the system light comprises the first device light and the luminescent material light, wherein the first angles of incidence (1) and the first intensities in the operational mode are selected such that in a plane perpendicular to the downstream side over an angle of at least 90 a color variation in u or a color variation in v over the angle is at maximum 0.03.

15. The light generating system according to claim 14, wherein the luminescent body comprises a luminescent material, and wherein the luminescent material comprises a luminescent material of the type A.sub.3B.sub.5O.sub.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.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) 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:

(2) FIG. 1 schematically depicts an embodiment;

(3) FIG. 2a-2b schematically depict some aspects; and

(4) FIG. 3 schematically depicts an embodiment of a light generating system; and

(5) FIG. 4 schematically depict some embodiments and applications.

(6) The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(7) FIG. 1 schematically depicts an embodiment of a light generating system 1000 comprising: (i) a first set 1100 comprising n1 first light generating devices 110, (ii) a first optical element 410, and (iii) a luminescent body 200.

(8) The n1 first light generating devices 110 are configured to generate first device light 111. The first set 1100 may comprise k1 first subsets 1115 of each at least one first light generating device 110 of the n1 first light generating devices 110. Especially, n13, especially n15 and 2k1n1. Here, two subsets 1115 are schematically depicted, one indicated as first subset 1115a and one indicated as second subset 1115b. Here, in this schematic cross-sectional drawings. The first subset 1115a comprises at least a single first light generating devices 110 and the second subset 1115b comprises at least two first light generating devices 110.

(9) In embodiments of the light generating system 1000, the n1 first light generating devices 110 comprise lasers.

(10) Especially, the n1 first light generating devices 110 are configured to generate first device light 111 having a wavelength selected from the range of 380-495 nm. The luminescent body 200 may be configured to: (i) convert part of the first device light 111 into luminescent material light 211, and (ii) transmit part of the first device light 111.

(11) The n1 first light generating devices 110 and the first optical element 410 are configured to provide first beams 115 of first device light 111 to the luminescent body 200, two or more first beams 115 of two or more first light generating devices 110 (from two or more different first subsets 1115) of the k1 first subsets 1115 have different first angles of incidence al relative to a normal to the luminescent body 200. A first beam 115a may be based on the first light generating device(s) 110 of the first subset 1115a, and the second beams 115b may be based on the first light generating devices 110 of the second subset 1115b. The beams 115 downstream of the first optical element 410 may be characterized by their optical axes, which may have the respective first angles of incidence al with a normal to the luminescent body 200. The first angles of incidence al is essentially 0 for the first beam 115a, and the first angles of incidence al may be approximately 25 in this schematical drawing.

(12) In an operational mode of the light generating system 1000 a first intensity of the first device light 111 of the k1 first subsets 1115 may be dependent upon the first angles of incidence al. In specific embodiments (of the light generating system 1000), in the operational mode the first intensity of the first device light 111 of the k1 first subsets 1115 increases with increasing first angle of incidence 1. Schematically, the slanted beams 115b are depicted with thicker arrows, indicating a higher intensity, than the essentially parallel to normal propagating beam 115a.

(13) Especially, at least two of the two or more first beams 115 of two or more first light generating devices 110 of the k1 first subsets 1115 have first angles of incidence (1) relative to the normal to the luminescent body 200 differing with a mutual angle selected from the range of 15-135. Note that here three angles of incidence are shown, or three optical axes, with the two beams having an angle al with the normal. Note that it is not necessary that these two beams have the same angle of incidence. However, in embodiments symmetric configurations may be chosen.

(14) In specific embodiments, in the operational mode a ratio of a highest first intensity (I.sub.1,max) and a lowest first intensity (I.sub.1,min) of the first device light 111 of the k1 first subsets 1115, upstream of the luminescent body 200 may be selected from the range of 1.04(I.sub.1,max/I.sub.1,min)10.

(15) In embodiments, the luminescent body 200 has a body height H1 and a scattering mean free path ls for the first device light 111. Especially, ls>*H1. The width is indicated with reference W1. The width W1 may in specific embodiments be a diameter D. In rectangular embodiments, there may be a length L1 perpendicular to the width W1 and the height H1 (see also FIG. 2b).

(16) In embodiments, the luminescent body 200 may comprise a single crystalline body or a ceramic body.

(17) In embodiments, the luminescent body 200 has a transmission for perpendicularly provided first device light 111 in the range of 5-20%.

(18) The luminescent body 200 may be configured to convert part of the first device light 111 into luminescent material light 211 having a wavelength in the 495-605 nm.

(19) Especially, the luminescent body 200 has an upstream face 201, configured in a light receiving relationship with the n1 first light generating devices 110, and a downstream face 202 from which during the operational mode (a) first device light 111 after transmission through the luminescent body 200, and (b) luminescent material light 211, escape. The upstream face 201 and the downstream face 202 may also be indicated as main faces. The main faces may be bridged by and edge. A cross-section of the luminescent body 200, parallel to one of the main faces may e.g. be circular or rectangular.

(20) The light generating system 1000 may be configured to generate system light 1001. In the operational mode the system light 1001 may comprise the first device light 111 and the luminescent material light 211. In embodiments, in the operational mode the system light 1001 may be white light.

(21) In specific embodiments the light generating system 1000 may further comprising a control system 300.

(22) In embodiments, the k1 first subsets 1115 (of each at least one first light generating device 110 of the n1 first light generating devices 110) may individually be controllable. The control system 300 may be configured to control the k1 first subsets 1115.

(23) Referring also to FIG. 2a, in embodiments, the first angles of incidence (1) and the first intensities in the operational mode are selected such that in a plane perpendicular to the downstream side over an angle of at least 90 (in that plane) a color variation in u or a color variation in v over the angle may be at maximum 0.03.

(24) FIG. 2b (see also FIG. 1) schematically depicts top view of possible luminescent bodies 200, with the dashed lines indicated plane perpendicular to the downstream side 202 of the luminescent body. Left a rectangular luminescent body 200 is depicted and right a circular luminescent body 200 is depicted. Other shapes may also be possible. The dashed circle indicates luminescent light and device light escaping from the downstream side 202 of the luminescent body 200. This may be system light 1001.

(25) Referring also to FIG. 3, in embodiments the light generating system 1000 may further comprise a second optical element 420. The second optical element 420 may comprise a lens array with m1 lenslets 425 or collimator element 426. The m1 lenslet 425 or collimator element 426 may be configured downstream of the n1 first light generating devices 110 and upstream of the first optical element 410. In embodiments, m1=n1. In embodiments, the m1 lenslets 425 or collimator element 426 may be configured to collimate the first device light 111 of the n1 first light generating devices 110.

(26) In specific embodiments, the light generating system 1000 may further comprise a second set 1200 comprising n2 second light generating devices 120. The second light generating devices 120 may be configured to generate second device light 121 (having a spectral power distribution different from the first device light 111).

(27) The second set 1200 may comprise k2 second subsets 1125 of each at least one second light generating device 120 of the n2 second light generating devices 120. In embodiments, n23, especially n25. Especially, in embodiments 2k2n2.

(28) In embodiments, the luminescent body 200 has a transmission for perpendicularly provided second device light 111 of at least 50%.

(29) The n2 second light generating devices 120 and the first optical element 410 are configured to provide second beams 125 of second device light 121 to the luminescent body 200.

(30) Two or more second beams 125 of two or more second light generating devices 120 (from two or more different second subsets 1125) of the k2 second subsets 1125 have different second angles of incidence 2 relative to the normal to the luminescent body 200.

(31) In an operational mode of the light generating system 1000 a second intensity of the second device light 121 of the k2 second subsets 1125 may be dependent upon the second angles of incidence 2. Especially, in the operational mode the second intensity of the second device light 121 of the k2 second subsets 1125 may decrease with increasing second angle of incidence 2. This is schematically indicated with the dashed lines, where more intensity is in the more perpendicular beam and less intensity is in the more slanted beams.

(32) In embodiments, the n2 second light generating devices 120 comprise lasers.

(33) Here, by way of example the first set 1100 has now a collimator element 426 configured downstream thereof, and the second set 1200 has m1 lenslets 425 configured downstream thereof. Of course, other embodiments may also be possible.

(34) Referring to especially FIGS. 1 and 3, one or more of the following may apply: (i) the n1 first light generating devices 110 comprise vertical-cavity surface-emitting lasers, and (ii) the n2 second light generating devices 120 comprise vertical-cavity surface-emitting lasers.

(35) In specific embodiments, the n2 second light generating devices 120 may be configured to provide second device light 121 having a wavelength in the 605-780 nm.

(36) Referring to FIG. 3, the light generating system 1000 may further comprise a third optical element 430. The third optical element may comprise a beam combiner. The third optical element 430 may be configured downstream of the n1 first light generating devices 110 and the n2 second light generating devices 120, and upstream of the first optical element 410. The third optical element 430 may be configured to combine the first device light 111 and the second device light 121.

(37) Optical modelling was performed, which showed that a substantial reduction in the color over angle effect could be obtained.

(38) FIG. 4 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. FIG. 3 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000. Hence, FIG. 4 schematically depicts embodiments of a lighting device 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, and an optical wireless communication device, comprising the light generating system 1000 as described herein. In embodiments, such lighting device may be a lamp 1, a luminaire 2, a projector device 3, a disinfection device, or an optical wireless communication device. Lighting device light escaping from the lighting device 1200 is indicated with reference 1201. Lighting device light 1201 may essentially consist of system light 1001, and may in specific embodiments thus be system light 1001.

(39) Referring to the preceding Figures, in specific embodiments, in the operational mode the first intensity of the first device light 111 of the k1 first subsets 1115 may increase with increasing first angle of incidence (1), the n1 first light generating devices 110 comprise lasers, and the light generating device 1200 may be configured to generate white light 1201 having a CCT selected from the range of 2700-4000 k and having a CRI of at least 80.

(40) The term plurality refers to two or more.

(41) 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%.

(42) The term comprise also includes embodiments wherein the term comprises means consists of.

(43) 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.

(44) 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.

(45) 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.

(46) 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.

(47) In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

(48) 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.

(49) The article a or an preceding an element does not exclude the presence of a plurality of such elements.

(50) 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.

(51) 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.

(52) 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.

(53) 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.