Illumination device for pixelated illumination

• US 8,371,713 B2
• Filed: 09/09/2008
• Issued: 02/12/2013
• Est. Priority Date: 09/13/2007
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Van As, Marco
• Primary Examiner(s): Ward, John A
• Application Number:
  US12/676,636
• Publication Number:
  US 20100302774A1
• Time in Patent Office: 1,617 Days
• Field of Search: 362/245, 362/311.02, 362/231, 362/235, 362/240, 362/241, 362/246, 362/249.01, 362/296.01, 353/37, 353/98, 359/34, 385/129, 385/133
• US Class Current: 362/235
• CPC Class Codes: H04N 9/3138 using arrays of modulated light sources electroluminescent display devices G09G3/30

Abstract

An illumination device (1) for pixelated illumination of a target area (3) comprising: an array (4) of light emitting devices; projection optics (5) arranged in between the array (4) of light emitting devices and the target area (3); a reflecting structure (6) having a first opening (9) facing the array (4) of light emitting devices and a second opening (10) facing the projection optics (5), and a reflective surface connecting the first and second opening, the surface enclosing and facing an optical axis (11) of the projection optics (5). The projection optics (5) is adapted to image the array (4) of light emitting devices, and a virtual extension thereof created by the reflecting structure (6), onto the target area (3), thereby generating an extended pixelated illumination pattern (2). By utilizing a reflecting structure to create a virtual extension of the array of light emitting devices, a high degree of pixelation can be achieved in the illumination pattern while minimizing the number of light emitting devices required. Thus, increased efficiency and reduce costs can be achieved.

Claims

1. An illumination device for pixelated illumination of a target area, the device comprising:

an array of light emitting devices;

projection optics arranged in between said array of light emitting devices and said target area; and

a reflecting structure having a first opening facing said array of light emitting devices and a second opening facing said projection optics, and a reflective surface connecting said first and second opening, said surface enclosing and facing an optical axis of said projection optics, wherein said projection optics is configured to image said array of light emitting devices, and a virtual extension thereof created by said reflecting structure, onto said target area, thereby generating an extended pixelated illumination pattern, wherein a distance between said array of light emitting devices and the reflecting structure measured in a plane where the light emitting devices are arranged, corresponds to half the spacing between the light emitting devices comprised in the array of light emitting devices.

2. An illumination device according to claim 1, wherein said first opening is located adjacent to a plane in which said array of light emitting devices are arranged.

3. An illumination device according to claim 1, wherein said first opening is arranged around said array of light emitting devices.

4. An illumination device according to claim 1, wherein a cross-section of the first opening has a shape essentially corresponding to the shape of said array of light emitting devices.

5. An illumination device according to claim 1, wherein a cross-section of the first opening has a shape essentially corresponding to the shape of said projection optics.

6. An illumination device according to claim 1 wherein a cross-section of said first opening has a shape selected from the group consisting of:

triangle, rectangular, pentagon, hexagon, circular and octagon.

7. An illumination device according to claim 1, wherein a cross-section of the reflecting structure has a shape essentially corresponding to the shape of the cross-section of the first opening throughout the extension of the reflecting structure.

8. An illumination device according to claim 1, wherein a relationship between a focal length f of the projection optics, a distance v between said array of light emitting devices and said projection optics, and a distance b between said projection optics and said target area, is defined by the following formula:

9. An illumination device according to claim 1, wherein an extension of said reflecting structure in the direction of the optical axis, is such that an outer periphery of said second opening is tangent to an imaginary straight line drawn from the periphery of the projection optics through the optical axis to the periphery of an area, in the plane where said array of light emitting devices are arranged, corresponding to the area that can be captured by the projection optics.

10. An illumination device according to claim 1, wherein a cross-section of said first opening is smaller than a cross-section of said second opening.

11. An illumination device according to claim 1, wherein the reflective surface connecting the first and second opening is such that for any point on an periphery of said first opening an imaginary straight line can be drawn along said surface to a point on an periphery of said second opening.

12. An illumination device according to claim 1, wherein said reflective surface is formed by at least three essentially flat, essentially rectangular walls arranged side-by-side.

13. An illumination device according to claim 1, wherein said projection optics is a projection lens.

14. An illumination device according to claim 1, wherein said array of light emitting devices comprises at least a first light emitting diode (R) of a first color and at least a second light emitting diode (G) of a second color, wherein the first and the second colors are distinct from each other.

15. An illumination device according to claim 1, further comprising a light-shaping diffusor disposed between said array of light emitting devices and said projection optics.