Illumination device with remote luminescent material
The invention provides an illumination device comprising a light source and a transmissive arrangement. The light source is arranged to generate light source light and comprises a light emitting device (LED), arranged to generate LED light and a carrier comprising a first luminescent material. The carrier is in contact with the LED and the first luminescent material is arranged to convert at least part of the LED light into first luminescent material light. The transmissive arrangement of a second luminescent material is arranged remote from the light source and is arranged to convert at least part of the LED light or at least part of the first luminescent material light and/or at least part of the LED light. The invention overcomes current limitations of remote luminescent material systems in spot lighting. In addition, an extremely simple way of realizing light sources with various correlated color temperatures is allowed, based on just a single type of white (or whitish) light source in combination with various (red-orange) remote luminescent materials.
1. An illumination device comprising:
a light source, arranged to generate light source light, comprising:
a light emitting device (LED), arranged to generate LED light;
a carrier comprising a first luminescent material, wherein the carrier is in contact with the LED, and wherein the first luminescent material is arranged to convert at least part of the LED light into first luminescent material light;
wherein the first luminescent material is a low light scattering material and wherein the first luminescent material provides a relative high heat conduction to the LED;
a transmissive arrangement of a second luminescent material, arranged remote from the light source and the carrier such that an air gap is formed between the carrier and the transmissive arrangement, the transmissive arrangement arranged to convert at least part of the LED light or at least part of the first luminescent material light, or at least part of the LED light and at least part of the first luminescent material light into second luminescent material light;
wherein the second luminescent material is a high light scattering material.
2. The illumination device according to claim 1 , wherein the LED comprises a blue emitting LED, wherein the first luminescent material is arranged to emit light with a dominant wavelength in the yellow-green spectral range, and wherein the second luminescent material is arranged to emit light with a dominant wavelength in the red-orange range.
3. The illumination device according to claim 1 , wherein the LED comprises a blue emitting LED, wherein the first luminescent material comprises one or more luminescent materials selected from the group consisting of a trivalent cerium containing garnet, a divalent europium containing oxynitride, a divalent europium containing silicate, a divalent europium containing thiogallate, and wherein the second luminescent material comprises one or more luminescent materials selected from the group consisting of a trivalent cerium containing earth alkali sulphide and a divalent europium containing nitride.
4. The illumination device according to claim 1 , wherein the second luminescent material comprises (Ca,Sr,Ba)AlSiN3:Eu.
5. The illumination device according to claim 1 , wherein the second luminescent material comprises (Ca,Sr,Ba)2Si5N8:Eu.
6. The illumination device according to claim 1 , wherein the carrier comprises a luminescent ceramic.
7. The illumination device according to claim 1 , wherein the carrier comprises a luminescent material layer.
8. The illumination device according to claim 1 , wherein the carrier comprises an encapsulant comprising the first luminescent material.
9. The illumination device according to claim 1 , wherein the carrier and the transmissive arrangement are in contact with a heat sink.
10. The illumination device according to claim 1 , wherein the transmissive arrangement comprises a coating coated to an exit window, wherein the coating comprises the second luminescent material.
11. The illumination device according to claim 1 , wherein the transmissive arrangement comprises an exit window comprising the second luminescent material.
12. The illumination device according to claim 1 , wherein the transmissive arrangement includes an exit window which has a hollow shape and encloses at least partially the light source.
13. The illumination device according to claim 1 , wherein the light source light is white light, having a colour point within 15 SDCM, standard deviation of colour matching, of the black body locus.
14. The illumination device according to claim 1 , wherein the second luminescent material is arranged to convert at least part of the first luminescent material light.
15. The illumination device according to claim 1 , wherein the illumination device is arranged to generate illumination device light comprising first luminescent material light and second luminescent material light and optionally LED light, wherein the illumination device further comprises a collimator which at least partially encloses the light source and the transmissive arrangement and which is arranged to collimate the illumination device light.
16. An illumination device comprising:
a light source arranged to generate light source light, comprising:
a light emitting device (LED) arranged to generate LED light;
a carrier positioned over the LED and including a first luminescent material, wherein the carrier is in contact with the LED and wherein the first luminescent material is arranged to convert a substantial portion of the LED light into first luminescent material light;
wherein the first luminescent material is a low light scattering material, the LED emits a substantially blue LED light and the first luminescent material light is a short wavelength light;
a transmissive arrangement of a second luminescent material, arranged remote from the carrier such that an air gap is formed between the carrier and the transmissive arrangement, the transmissive arrangement arranged to convert at least part of the LED light or at least part of the first luminescent material light, or at least part of the LED light and at least part of the first luminescent material light into second luminescent material light;
wherein the second luminescent material light has a longer wavelength than the first luminescent material light.
17. An illumination device comprising:
a light source arranged to generate light source light, comprising:
a light emitting device (LED) arranged to generate LED light;
a carrier positioned over the LED and including a first luminescent material, wherein the carrier is in contact with the LED and wherein the first luminescent material is arranged to convert a substantial portion of the LED light into first luminescent material light;
wherein the first luminescent material is a low light scattering material, having a yellow-green phosphor
a transmissive arrangement of a second luminescent material, arranged at a non-zero distance from the light source and the carrier such that an air gap is formed between the carrier and the transmissive arrangement, the transmissive arrangement arranged to convert at least part of the LED light or at least part of the first luminescent material light, or at least part of the LED light and at least part of the first luminescent material light into second luminescent material light;
wherein the second luminescent material light has one of a red or red-orange phosphor.