High Brightness Illumination Device With Incoherent Solid State Light Source

• US 20080247169A1
• Filed: 03/14/2005
• Published: 10/09/2008
• Est. Priority Date: 03/16/2004
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Zou, Hans, Anderson, Duncan J.
• Granted Patent: US 7,740,375 B2
• Time in Patent Office: Days
• US Class Current: 362/296
• CPC Class Codes: G02B 6/4298 coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

An illumination light source includes an incoherent solid state light source adapted to emit light over at least one light emission surface and having a total light emission surface area S₀; a light circulation device including at least one light receiving surface adapted to receive the light from the incoherent solid state light source, and a light extraction area having a first surface area S₁; and a light extraction device for extracting the light from the light circulation device at the light extraction area, wherein S₁<S₀. Accordingly, the apparent brightness of the light is increased by distributing it over a smaller area.

Claims

1. An illumination device (100), comprising:

an incoherent solid state light source (110) adapted to emit light over at least one light emission surface (112) and having a total light emission surface area S₀; and

a reflective cavity (120) having an entrance aperture (122) adapted to receive the light from the incoherent solid state light source (110) and a light extraction aperture (124) adapted to output the light from the incoherent solid state light source (110),

wherein a surface area S₁ of the light extraction aperture (124) of the reflective cavity (120) is smaller than the surface area S₀.

2. The illumination device (100) of claim 1, wherein the incoherent solid state light source (210) consists of a single extended LED.

3. The illumination device (100) of claim 1, wherein the incoherent solid state light source (210) comprises an array of LEDs.

4. The illumination device (100) of claim 1, wherein the light extraction aperture has a rectangular shape and as aspect ratio of 16:

9.

5. An illumination device (100), comprising:

an incoherent solid state light source (110) adapted to emit light over at least one light emission surface (112) and having a total light emission surface area S₀; and

a reflective layer (129) disposed directly on and covering the incoherent solid state light source (110) and having therein an opening (124) for outputting the light from the incoherent solid state light source (110),

wherein a surface area S₁ of the opening (124) of the reflective layer (129) is smaller than the surface area S₀.

6. The illumination device (100) of claim 5, further comprising a refractive index matching material disposed on an area of the first surface that is not covered with the reflective layer.

7. The illumination device (100) of claim 5, wherein the opening has a rectangular shape and as aspect ratio of 16:

9.

8. An illumination device (200, 300, 400, 500, 600), comprising:

an incoherent solid state light source (210) adapted to emit light over at least one light emission surface (212) and having a total light emission surface area S₀;

a light circulation device (220) including

at least one light receiving surface (222) adapted to receive the light from the incoherent solid state light source (210), and

a light extraction area (224) having a surface area S₁; and

light extraction means (230) for extracting the light from the light circulation device (220) at the light extraction area (224),

wherein S₁ is smaller than S₀.

9. The illumination device (200, 300, 400, 500, 600) of claim 8, wherein the light circulation device (220) comprises a solid light guide.

10. The illumination device (200, 300, 400, 500, 600) of claim 9, wherein the light circulation device (220) further comprises a reflective material disposed on a surface of the light guide which does not support total internal reflection.

11. The illumination device (200, 300, 400, 500, 600) of claim 8, wherein the light circulation device (220) comprises a hollow cavity.

12. The illumination device (200, 300, 400, 500, 600) of claim 8, wherein the light extraction means (230) comprises a light collimating structure.

13. The illumination device (200, 300, 500, 600) of claim 8, wherein the light extraction means (230) comprises a compound parabolic collimator.

14. The illumination device (400) of claim 8, wherein the light extraction means (450) comprises a prismatic optical component.

15. The illumination device (300) of claim 8, further comprising a reflective polarizer (340) disposed in an optical path between the light extraction area (224) and the light extraction means (230),

wherein the light circulation device (220) includes at least one diffusing reflector (339) disposed at a sidewall thereof.

16. The illumination device (300) of claim 8, wherein the light circulation device (220) includes at least one specular reflector (339) disposed at a sidewall thereof, said illumination device (300) further comprising:

a reflective polarizer (340) disposed in an optical path between the light extraction area (224) and the light extraction means (230); and

a quarter wavelength foil (345) in an optical path between the specular reflector (339) and the reflective polarizer (340).

17. The illumination device (400) of claim 8, wherein the light circulation device (220) includes at least two light receiving surfaces (222) and the incoherent solid state light source 210 includes at least two light-emitting components, each light-emitting component being disposed adjacent to and confronting a corresponding one of the light receiving surfaces (222).

18. The illumination device (500) of claim 8, wherein the light circulation device (220) has a cross-section who thickness is less near the light extraction area (224) than at the light receiving surface (222).

19. The illumination device (600) of claim 8, further comprising:

a second incoherent solid state light source adapted to emit light over at least a second light emission surface (212),

wherein the light circulation device (220) includes at least a second light receiving surface (222) adapted to receive the light from the second incoherent solid state light source (210), and

wherein the two incoherent solid state light sources each emit light having a different spectral color.

20. The illumination device (100) of claim 8, wherein the incoherent solid state light source (210) consists of a single extended LED.