Laser SMD package with phosphor and light incoupler

Abstract

The invention provides a light generating system (1000) comprising a lighting unit (100), a luminescent element (210), an optical element (400), and a reflective element (510), wherein: (a) the lighting unit (100) is configured to generate a beam (102) of unit light (101); (b) the luminescent element (210) comprises a luminescent material (200) configured to convert at least part of the unit light (101) into luminescent material light (201); wherein the luminescent element (210) comprises a first luminescent element face (211) and a second luminescent element face (212), wherein at least part of the luminescent material (200) is configured between the first luminescent element face (211) and the second luminescent element face (212); (c) the optical element (400) comprises an external surface (410), wherein the optical element (400) is configured between the luminescent element (210) and 10 the reflective element (510), wherein a first part (421) of the external surface (410) is directed to the second luminescent face (212), wherein a second part (422) of the external surface (410) is directed to the reflective element (510), and wherein a third part (423) of the externa surface (410) is configured in a light receiving relationship with the lighting unit (100); wherein a first area A1 of the first part (421) is smaller than a second area A2 of the second part (422), wherein the optical element (400) is transmissive for the unit light (101); (d) the reflective element (510) is configured to reflect unit light (101); and (e) the lighting unit (100) is configured such that in an operational mode the lighting unit (100) is configured to irradiate the first element face (211) via transmission through the optical element (400) and reflection at the reflective element (510).

Claims

1. A light generating system comprising a lighting unit, a luminescent element, an optical element, and a reflective element, wherein: the lighting unit is configured to generate a beam of unit light; the luminescent element comprises a luminescent material configured to convert at least part of the unit light into luminescent material light; wherein the luminescent element comprises a first luminescent element face and a second luminescent element face, wherein at least part of the luminescent material is configured between the first luminescent element face and the second luminescent element face; the optical element comprises an external surface, wherein the optical element is configured between the luminescent element and the reflective element, wherein a first part of the external surface is directed to the second luminescent face, wherein a second part of the external surface is directed to the reflective element, and wherein a third part of the external surface is configured in a light receiving relationship with the lighting unit; wherein a first area A1 of the first part of the external surface of the optical element is smaller than a second area A2 of the second part of the external surface of the optical element, wherein the optical element is transmissive for the unit light; the reflective element is configured to reflect unit light; and the lighting unit is configured such that in an operational mode the lighting unit is configured to irradiate the first luminescent element face via transmission through the optical element and reflection at the reflective element.

2. The light generating system according to claim 1, wherein the lighting unit is configured such that in the operational mode the lighting unit is configured to irradiate at least 20% of the second part via transmission through the optical element, and via reflection at the reflective element at least 70% of the second element face; wherein the reflective element is specular reflective.

3. The light generating system according to claim 1, wherein the optical element comprises a first face comprising the first part, a second face comprising the second part, and one or more third faces comprising the third part, wherein the first face and the second face are configured parallel, wherein the first face is in physical contact with the luminescent element, wherein the second face is in physical contact with the reflective element, wherein the third face and the first face have a first mutual angle .sub.1,3, and wherein the third face and the second face have a second mutual angle .sub.2,3, wherein 100.sub.1,3175, and wherein 5.sub.2,380.

4. The light generating system according to claim 1, wherein in a first plane (P1) perpendicular to the second part, relative to a first normal (N1) to the second part and configured in the first plane (P1), the beam has a smallest incidence angle (1) on the third part and a largest incidence angle (2) on the third part, wherein the third part has a third angle (3) with the normal (N1), wherein 3>1, and wherein the beam of unit light is defined by at least 1/e.sup.2 of a maximum of a spectral power of the unit light.

5. The light generating system according to claim 4, wherein the third angle (3) is selected from the range of 15-75.

6. The light generating system according to claim 4, wherein the beam of unit light is selected from the group consisting of a focused beam, and a collimated beam.

7. The light generating system according to claim 4, wherein the lighting unit comprises a light source configured to generate light source light, wherein the unit light comprises at least part of the light source light; wherein the light source is selected from the group consisting of a laser diode and a superluminescent diode.

8. The light generating system according to claim 7, wherein the lighting unit further comprises one or more second optical elements configured to one or more of (i) shape the beam of unit light, and (ii) direct the beam of unit light.

9. The light generating system according to claim 4, wherein the optical element has the shape of a frustum.

10. The light generating system according to claim 9, comprising a second reflective element, wherein the second reflective element is configured to reflect unit light that escapes from the optical element via the one or more third faces back into the optical element, wherein the third part has a third area A3, wherein the one or more third faces have a fourth area A4, wherein at least 50% of the fourth area A4 is directed to the second reflective element and wherein at maximum 25% of the fourth area A4 is defined by the third area A3.

11. The light generating system according to claim 4, comprising a thermally conductive element, wherein the reflective element is defined by the thermally conductive element or is configured as reflective layer on the thermally conductive element; and wherein the thermally conductive element comprises a heatsink.

12. The light generating system according to claim 4, wherein the optical element is selected from the group consisting of a ceramic body, a single crystal, glass, and quartz; and wherein the luminescent material comprise 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.

13. The light generating system according to claim 4, comprising a plurality of lighting units configured to irradiate different parts of the third part of the externa surface.

14. An integrated light source package comprising the light generating system according to claim 4.

15. 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 4.

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) FIGS. 1a-1g schematically depict some embodiments and aspects;

(3) FIG. 2 schematically depicts some applications. The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(4) Laser diodes, such as two laser diodes, may be arranged on the carrier via a holder and illuminate a phosphor tile under an angle of 60. The laser diodes may be arranged in the vicinity of the phosphor such that a large part of the laser light is directed onto the phosphor. Such a light emitting device can be mounted on a (secondary) heat sink. Laser-phosphor (surface mounted device) SMD can be used in high brightness lighting applications such as adaptive front lighting systems, stage lighting, projection, medical lighting, etc. It appears desirable to improve the spectral and/or spatial light distribution of laser-phosphor SMDs. Amongst others, herein in embodiments a laser SMD package is proposed with transmissive phosphor and using a sapphire light in-coupler for improved collection efficiency and spectral-spatial light distribution. The phosphor (tile) may be arranged on top of a transparent-shaped light in-coupler which may be arranged on top of a reflective heatsink. The angle at which the lasers are arranged and the side surfaces of the transparent-shaped light in-coupler may in embodiments be designed such that laser light is efficiently directed towards (and focused onto) the bottom surface of the phosphor tile. Instead of direct pumping, also indirect phosphor pumping via mirrors can be used to improve focusing of the light onto the phosphor. In addition, in embodiments the side surfaces of the transparent-shaped light in-coupler may comprise a reflector with a pinhole to further improve the efficiency. In specific embodiments, the bottom of the phosphor tile is pumped from multiple sides.

(5) FIG. 1a schematically depicts an embodiment of a light generating system 1000. The system 1000 comprises a lighting unit 100, a luminescent element 210, an optical element 400, and a reflective element 510. The luminescent element 210 comprises a first luminescent element face 211 and a second luminescent element face 212.

(6) The lighting unit 100 is especially configured to generate a beam 102 of unit light 101.

(7) The lighting unit 100 may comprise a light source 10 configured to generate light source light 11. In embodiments, the unit light 101 may comprise at least part of the light source light 11. Further, in embodiments the light source 10 may be selected from the group consisting of a laser diode and a superluminescent diode.

(8) The embodiment schematically depicted in FIG. 1a is an embodiment of the light generating system 1000 comprising a plurality of lighting units 100 configured to irradiate different parts of the third part 423 of the external surface 410.

(9) Further, FIG. 1a schematically also depicts an embodiment of an integrated light source package 10000 comprising the light generating system 1000. The integrated light source package 10000 may comprise a common support member 11000, configured to support directly or via intermediate elements the light source(s) 100, the optical element 400, and the luminescent element 210. The common support member 11000 may in embodiments essentially consist of the reflective element 510 and/or a thermally conductive element 500 (see also below).

(10) The reflective element 510 is configured to reflect unit light 101. In embodiments, the reflective element 510 is specular reflective.

(11) Further aspects of the embodiment and other embodiments are described also with reference to FIG. 1b, wherein a first embodiment I schematically depicts an embodiment wherein the lighting unit 100 provides a divergent beam 102, embodiment II schematically depicts a focused beam 102, and embodiment III schematically depicts a (fully) collimated beam 102.

(12) The luminescent element 210 comprises a luminescent material 200, especially configured to convert at least part of the unit light 101 into luminescent material light 201. The luminescent element 210 comprises a first luminescent element face 211 and a second luminescent element face 212. Especially, at least part of the luminescent material 200 is configured between the first luminescent element face 211 and the second luminescent element face 212. In embodiments, the luminescent material 200 comprise 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.

(13) The optical element 400 comprises an external surface 410. Especially, the optical element 400 is configured between the luminescent element 210 and the reflective element 510.

(14) A first part 421 of the external surface 410 may be directed to the second luminescent face 212 and a second part 422 of the external surface 410 may be directed to the reflective element 510. Especially, a third part 423 of the externa surface 410 is configured in a light receiving relationship with the lighting unit 100. Hence, at least part of the third part may receive lighting unit light 101. A first area A1 of the first part 421 may be smaller than a second area A2 of the second part 422. Hence, the area of the first part 421 is indicated with reference A1 and the area of the second part 422 is indicated with reference A2. The optical element 400 is transmissive for the unit light 101. The optical element 400 may be selected from the group consisting of a ceramic body, a single crystal (such as alumina, like e.g. sapphire), glass, and quartz.

(15) The lighting unit 100 is configured such that in an operational mode the lighting unit 100 is configured to irradiate the first element face 211, especially via transmission through the optical element 400 and reflection at the reflective element 510.

(16) In embodiments, the lighting unit 100 may be configured such that in the operational mode the lighting unit 100 is configured to irradiate at least 20% of the second element face 212 via transmission through the optical element 400 and reflection at the reflective element 510.

(17) In embodiments, the lighting unit 100 may be configured such that in the operational mode the lighting unit 100 is configured to irradiate at least 20% of the second part 422 via transmission through the optical element 400, and via reflection at the reflective element 510 (downstream of the second part 422). Further, in embodiments the lighting unit 100 may be configured such that in the operational mode the lighting unit 100 is configured to irradiate at least 70% of the second element face 212.

(18) In embodiments, the optical element 400 may comprise a first face 411 comprising the first part 421, a second face 412 comprising the second part 422, and one or more third faces 413 comprising the third part 423, wherein the first face 411 and the second face 412 are configured parallel, wherein the first face 411 is in physical contact with the luminescent element 210, wherein the second face 412 is in physical contact with the reflective element 510.

(19) Reference 440 refers to an embodiment of (yet) a further optics, like a beam shaping element, such as a lens.

(20) FIGS. 1a and 1b further schematically depict embodiments wherein the third angle 3 is selected from the range of 15-75, see especially FIG. 1b.

(21) Referring to FIG. 1b, the beam 102 of unit light 101 is selected from the group consisting of a divergent beam, a focused beam, and a collimated beam, see embodiments I-III, respectively.

(22) Referring to FIG. 1c, the lighting unit 100 may further comprise one or more second optical elements 120 configured to one or more of (i) shape the beam 102 of unit light 101, and (ii) direct the beam 102 of unit light 101. In specific embodiments, the one or more second optical elements 120 comprise one or more parabolic mirrors.

(23) FIG. 1d schematically depicts embodiments wherein the third face 413 and the first face 411 have a first mutual angle .sub.1,3, and wherein the third face 413 and the second face 412 have a second mutual angle .sub.2,3, wherein 100.sub.1,3175, and wherein 5.sub.2,380.

(24) The optical element 400 may have the shape of a frustum, with one or more edges defined by the one or more third faces 413. In embodiment I, a conical frustum is schematically depicted, in embodiment II a right pyramidal frustum, and in embodiment III a hexagonal pyramidal frustum.

(25) FIG. 1e schematically depicts an embodiment wherein the reflective element 510 and a thermally conductive element 500 are the same element (on the left), and wherein the reflective element 510 may be a layer on the thermally conductive element 500 (on the right). Hence, the light generating system 1000 may comprise a thermally conductive element 500, wherein the reflective element 510 is defined by the thermally conductive element 500 or is configured as reflective layer on the thermally conductive element 500; and wherein the thermally conductive element 500 comprises a heatsink.

(26) FIG. 1f schematically depicts an embodiment of the light generating system 1000, comprising a second reflective element 420. The second reflective element 420 may be configured to reflect unit light 101 that escapes from the optical element 400 via the one or more third faces 413 back into the optical element 400. The third part 423 may have a third area A3. The one or more third faces 413 may have a fourth area A4. At least 50% of the fourth area A4 may be directed to the second reflective element 420. In embodiments, at maximum 25% of the fourth area A4 may be defined by the third area A3.

(27) FIG. 1g schematically depicts a cross-sectional view of a beam of light, with an optical axis O1. The optical axis O1 may coincide with the maximum of the spectral power distribution. The inner ring indicates all intensities between 100% of the spectral power (i.e. the maximum spectral power) and 1/e.sup.2*100% of the maximum spectral power. The largest outer ring may e.g. indicate all intensities between 100% of the spectral power and 10% of the maximum spectral power. Reference M indicates the maximum.

(28) FIG. 2 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. 2 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. Reference 1200 refers to a lighting device, which may e.g. be selected from the group of a lamp 1, a luminaire 2, a projector device 3. The lighting device 1200 comprises the light generating device 1000. However, in embodiments the lighting device 1200 may also comprise a disinfection device or an optical wireless communication device (comprising the light generating device 1000). FIG. 2 also schematically depicts an embodiment of the lighting device 1200 comprising a wall light device (such as especially wall washers). The lighting device 1200 may also comprise a cove lighting device (for illuminating a cove).

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

(30) 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.

(31) 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.

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

(33) 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.

(34) 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.

(35) 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.

(36) 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.

(37) 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.

(38) Amongst others, the invention proposes in specific embodiments a sapphire (or other material) light in-coupler for improved collection efficiency and spectral-spatial light distribution. The phosphor (tile) may be arranged on top of a transparent-shaped light in-coupler which may be arranged on top of a reflective heatsink. The angle at which the lasers are arranged as well as the angles of the side surfaces of the transparent-shaped light in-coupler may especially be designed such that laser light is efficiently directed towards (and focused onto) the bottom surface of the phosphor tile. Instead of direct pumping, in embodiments also indirect phosphor pumping via mirrors can be used which may improve focusing of the light onto the phosphor. In addition, the side surfaces of the transparent-shaped light in-coupler may in specific embodiments comprise a reflector with a pinhole to further improve the efficiency. In specific embodiments, the bottom of the phosphor tile may be pumped from multiple sides.

(39) The light generating system may comprise a lighting unit, a luminescent element, an optical element, and a reflective element. In embodiments, the light generating system may comprise a plurality of lighting units, a single luminescent element, a single optical element, and a single reflective element. In embodiments, the light generating system may comprise one or more lighting units, a single luminescent element comprising two or more luminescent materials, a single optical element, and a single reflective element. In embodiments, the light generating system may comprise (i) a plurality of arrangements, each comprising one or more lighting units, a luminescent element (comprising one or more luminescent materials), a single optical element, and (ii) one or more reflective element.

(40) In embodiments, in operation unit light enters the optical element via the third part, propagates in the direction of the second part, may escape from the second part, and is reflected back into the optical element by the reflective element, and enters again in the optical element via the second part, and propagates to the first part, and may escape from the optical element via the first part and enter the luminescent element. There, at least part of the unit light may be converted into luminescent material light.