Lighting device, array of lighting devices and optical projection device

• US 8,662,672 B2
• Filed: 10/03/2008
• Issued: 03/04/2014
• Est. Priority Date: 10/08/2007
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Hikmet, Rifat Ata Mustafa, Balkenende, Abraham Rudolf
• Primary Examiner(s): Legasse, Jr., Francis M
• Assistant Examiner(s): BROOKS, JERRY L.
• Application Number:
  US12/681,131
• Publication Number:
  US 20100231863A1
• Time in Patent Office: 1,978 Days
• Field of Search: 353/31, 349/121, 358/61, 362/83
• US Class Current: 353/31
• CPC Class Codes: G03B 21/20 Lamp housings
• CPC Class Codes: G03B 21/204 using secondary light emission, e.g. luminescence or fluorescence using different colours G03B33/00; if related to video signals H04N9/3197
• CPC Class Codes: H04N 9/3129 scanning a light beam on the display screen scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161
• CPC Class Codes: H04N 9/3161 using laser light sources using laser beams scanning the display screen H04N9/3129

Abstract

The invention relates to a lighting device (1), an array of such lighting devices and an optical projection device comprising such lighting device. The lighting device, comprises at least one laser source (4) for generating laser radiation, wherein the laser source is optically coupled to an optical element (7, 8, 9) comprising at least one luminescent material, suitable for emitting luminescent radiation upon laser excitation by the laser radiation, wherein the optical element is provided with at least one reflector for directing the radiation from the luminescent dot through an emission window of the optical element. The lighting device is particularly useful in a projector and other lighting applications.

Claims

1. A lighting device, comprising:

at least one laser source for generating laser radiation;

a plurality of optical elements; and

an optical switch configured to switch the laser radiation between at least two of the plurality of optical elements,

wherein each of the optical elements includes;

a solid exterior surface defining an internal volume of the optical element,

a light emission window disposed on the exterior surface,

at least one luminescent material for emitting luminescent radiation upon excitation by the laser radiation, and

a reflective coating disposed on at least a portion of one surface of the optical element for directing the emitted luminescent radiation from the luminescent material through the light emission window, wherein at least one of the laser radiation and the emitted luminescent radiation traverses at least a portion of the internal volume,

wherein at least two optical elements of the plurality of said optical elements comprise different luminescent materials for the emission of luminescent radiation of different wavelengths,

wherein the optical element has a cylindrical shape, wherein the at least one luminescent material is provided on a curved portion of the surface of the optical element having the cylindrical shape and wherein the emission window is defined by an essentially flat surface portion of the optical element having the cylindrical shape.

2. The lighting device of claim 1 wherein the luminescent material is a ceramic phosphor material.

3. The lighting device of claim 1 wherein the plurality of said optical elements comprises at least three different optical elements, wherein

a first optical element comprises a luminescent material for the emission of red light,

a second optical element comprises a luminescent material for the emission of green light, and

a third optical element comprises a luminescent material for the emission of blue light.

4. The lighting device of claim 3, wherein the device comprises multiple laser sources, wherein each laser source is optically coupled to at least one optical element.

5. The lighting device of claim 3, wherein at least one optical element is optically coupled to at least two different laser sources.

6. The lighting device of claim 1, wherein the optical switch comprises a laser reflector provided with displacement means for switching the direction of the reflected laser radiation.

7. The lighting device of claim 6, wherein the optical switch comprises active non-moving components, including active polarization rotators, active polarizing beam splitters and/or passive beam splitters.

8. The lighting device of claim 1, wherein the optical element defines a laser window for entry of the laser radiation, wherein the laser window is located away from the emission window.

9. The lighting device of claim 8, wherein the laser window is arranged for directing of the laser radiation towards the luminescent material in a direction essentially perpendicular to the emission window.

10. The lighting device of claim 8, wherein the emission window has a larger area than the laser window.

11. The lighting device of claim 8 wherein the optical element includes a dielectric reflector disposed at the laser window for selectively transmitting the laser radiation and reflecting the emitted radiation.

12. The lighting device of claim 1, wherein the at least one laser source is located at a distance from the optical element, wherein the laser source is optically coupled to the optical element through optical coupling means comprising at least one mirror element.

13. The lighting device of claim 1, wherein the device is provided with projection means for projecting the emitted radiation.

14. The lighting device of claim 13, wherein the projection means comprise an image-forming element.

15. A lighting device, comprising:

at least one laser source for generating laser radiation;

a plurality of optical elements; and

an optical switch configured to switch the laser radiation between at least two of the plurality of optical elements,

wherein each of the optical elements includes;

a solid exterior surface defining an internal volume of the optical element,

a light emission window disposed on the exterior surface,

at least one luminescent material for emitting luminescent radiation upon excitation by the laser radiation, and

a reflective coating disposed on at least a portion of one surface of the optical element for directing the emitted luminescent radiation from the luminescent material through the light emission window, wherein at least one of the laser radiation and the emitted luminescent radiation traverses at least a portion of the internal volume,

wherein at least two optical elements of the plurality of said optical elements comprise different luminescent materials for the emission luminescent radiation of different wavelengths,

wherein the optical element has a semi-spherical shape, wherein the at least one luminescent material is provided on a curved portion of the surface of the optical element having the semi-spherical shape and wherein the emission window is defined by an essentially flat surface portion of the optical element having the semi-spherical shape.

16. The lighting device of claim 15, wherein the plurality of said optical elements comprises at least three different optical elements, wherein

a first optical element comprises a luminescent material for the emission of red light,

a second optical element comprises a luminescent material for the emission of green light, and

a third optical element comprises a luminescent material for the emission of blue light.

17. The lighting device of claim 16, wherein the device comprises multiple laser sources, wherein each laser source is optically coupled to at least one optical element.

18. The lighting device of claim 15, wherein at least one optical element is optically coupled to at least two different laser sources.

19. The lighting device of claim 15, wherein the optical element defines a laser window for entry of the laser radiation, wherein the laser window is located away from the emission window.

20. The lighting device of claim 15, further comprising projection means for projecting the emitted radiation.