Lighting device
A lighting device is provided comprising at least one light-emitting element comprising a light-emitting surface configured to emit light; and a light-guiding sheet at least partially covering the light-emitting surface and comprising at least one cavity forming a passage for light emitted from the light-emitting surface. Thereby, at least one lateral surface limiting the at least one cavity is configured to reflect light emitted from the light-emitting surface. Further, a size of an opening of the at least one cavity facing the light-emitting surface is smaller than an area of the light-emitting surface.
1. A lighting device comprising:
at least one light-emitting element comprising a light-emitting surface configured to emit light;
a light-guiding sheet on and at least partially covering the light-emitting surface and comprising at least one cavity forming a passage for light emitted from the light-emitting surface, the at least one cavity comprising at least one lateral surface configured to reflect light emitted from the light-emitting surface, and
a size of an opening of the at least one cavity facing the light-emitting surface being smaller than an area of the light-emitting surface; and
at least one light-reflecting surface that is one of: arranged between the light-emitting surface of the at least one light-emitting element and the light-guiding sheet, corresponds to a portion of a top surface of the at least one light-emitting element, or corresponds to a portion of the light-guiding sheet facing the light-emitting surface of the at least one light-emitting element, the at least one light-reflecting surface being configured to reflect light emitted from the at least one light-emitting element in a direction towards the at least one light-emitting element.
2. The lighting device according to claim 1 , wherein the opening of the at least one cavity facing the light-emitting surface is smaller than an opening of the at least one cavity facing away from the light-emitting surface.
3. The lighting device according to claim 1 , wherein the at least one cavity is tapered in a direction towards the at least one light-emitting element.
4. The lighting device according to claim 1 , wherein the at least one lateral surface of the at least one cavity comprises a reflective coating.
5. The lighting device according to claim 1 , wherein the light-guiding sheet comprises or consists of glass, ceramic, silicone or metal.
6. The lighting device according to claim 1 , wherein the lighting device further comprises at least one wavelength conversion layer at least partially between at least a portion of the light-guiding sheet and at least a portion of the light-emitting surface.
7. The lighting device according to claim 1 , wherein the lighting device further comprises at least one wavelength conversion layer on the light-emitting surface and inside of the at least one cavity.
8. The lighting device according to claim 1 , wherein the at least one cavity is at least partially filled with a silicone configured to adhere to at least one of the light-emitting surface or the wavelength conversion layer arranged on the light-emitting surface.
9. The lighting device according to claim 1 , wherein the opening of the at least one cavity facing the light-emitting surface and an opening of the at least one cavity facing away from the light-emitting surface comprise different aspect ratios.
10. The lighting device according to claim 1 , wherein the light-guiding sheet comprises at least two cavities corresponding to the at least one light-emitting element forming respective passages for light emitted from the light-emitting surface of said at least one light-emitting element.
11. The lighting device according to claim 1 , wherein the at least one light-emitting element is a light-emitting diode on a printed circuit board.
12. Use of a lighting device according to claim 1 for automotive lighting, in particular for automotive head lighting.
13. The lighting device according to claim 1 , wherein the light-reflecting surface comprises a reflective coating.
14. A method for producing a lighting device, the method comprising:
providing at least one light-emitting element comprising a light-emitting surface configured to emit light;
providing a light-guiding sheet to be arranged on and at least partially cover the light-emitting surface;
forming at least one cavity in the light-guiding sheet to provide a passage for light emitted from the light-emitting surface, the at least one cavity being formed to have a size of an opening facing the light-emitting surface smaller than an area of the light-emitting surface and to have at least one lateral surface configured to reflect light emitted from the light-emitting surface in a direction towards the at least one light-emitting element; and
forming at least one light-reflecting surface to one of: be arranged in between the light-emitting surface of the at least one light-emitting element and the light-guiding sheet, correspond to a portion of a top surface of the at least one light-emitting element, or correspond to a portion of the light-guiding sheet facing the light-emitting surface of the at least one light-emitting element.
15. The method according to claim 14 , wherein the forming the at least one cavity further comprises applying a laser treatment to a portion of a material sheet.
16. The method according to claim 15 , further comprising applying an etching process at least to the portion of the material sheet to form the at least one cavity.
17. The method of claim 15 , wherein the portion of the material sheet comprises at least one of glass, ceramic, silicone or metal.