Illumination System

• US 20080062682A1
• Filed: 08/18/2005
• Published: 03/13/2008
• Est. Priority Date: 09/24/2004
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Ansems, Johannes, Hoelen, Christoph
• Application Number:
  US11/575,513
• Publication Number:
  US 20080062682A1
• Time in Patent Office: Days
• US Class Current: 362/231
• CPC Class Codes: F21K 9/69 Details of refractors forming part of the light source
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21V 7/05 plane
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

The illumination system has a light source (1) with a plurality of light emitters (R, G, B). The light emitters comprise at least a first light-emitting diode of a first primary color and at least a second light-emitting diode of a second primary color, the first and the second primary colors being distinct from each other. The illumination system has a facetted light-collimator (2) for collimating light emitted by the light emitters. The facetted light-collimator is arranged along a longitudinal axis (25) of the illumination system. Light propagation in the facetted light-collimator is based on total internal reflection or on reflection at a reflective coating provided on the facets of the facetted light-collimator. The facetted light-collimator merges into a facetted light-reflector (3) at a side facing away from the light source. The illumination system further comprises a light-shaping diffuser (17). The illumination system emits light with a uniform spatial and spatio-angular color distribution.

Claims

1. An illumination system comprising:

a light source (1) with a plurality of light emitters (R, G, B),

the light emitters (R, G, B) comprising at least a first light-emitting diode (R) of a first primary color and at least a second light-emitting diode (G) of a second primary color, the first and the second primary colors being distinct from each other,

a facetted light-collimator (2) for collimating light emitted by the light emitters (R, G, B),

the facetted light-collimator (2) being arranged along a longitudinal axis (25) of the illumination system,

light propagation in the facetted light-collimator (2) being based on total internal reflection or on reflection at a reflective coating provided on the facets of the facetted light-collimator (2),

the facetted light-collimator (2) merging into a facetted light-reflector (3) at a side facing away from the light source (1),

the illumination system comprising a light-shaping diffuser (17).

2. An illumination system as claimed in claim 1, wherein the light emitters (R, G, B) are arranged in the light source (1) such that the primary colors are distributed substantially rotationally symmetric with respect to a fictitious plane normal to the longitudinal axis (25).

3. An illumination system as claimed in claim 1, wherein the facetted light-collimator (2) is made from a dielectric material with a refractive index larger than or equal to 1.3.

4. An illumination system as claimed in claim 1, wherein the number of circumferential facets of the facetted light-collimator (2) taken normal to the longitudinal axis (25) at a side facing the light emitters (R, G, B) is between 4 and 10 square, hexagonal or octagonal cross-section taken normal to the longitudinal axis (25).

5. An illumination system as claimed in claim 4, wherein the number of facets of the facetted light-collimator (2) doubles from a side facing the light emitters (R, G, B) towards a side of the facetted light-collimator (2) facing away of the light emitters (R, G, B).

6. An illumination system as claimed in claim 1, wherein the facets of the facetted light-collimator (2) are provided with a reflective coating.

7. An illumination system as claimed in claim 1, wherein the facetted light-collimator (2) comprises contiguous, linear trapezoidal facets.

8. An illumination system as claimed in claim 1, wherein the facetted light-collimator (2) is provided with cavities for accommodating the light emitters (R, G, B), the cavities being provided with an encapsulant substantially matching the refractive index the facetted light-collimator (2).

9. An illumination system as claimed in claim 1, wherein the facetted light-reflector (3) comprises contiguous, linear trapezoidal facets.

10. An illumination system as claimed in claim 1, wherein the light-shaping diffuser (17) is provided at a distance from the light source (1), the distance being at least twice the effective diameter of the light source (1).

11. An illumination system as claimed in claim 9, wherein the light-shaping diffuser (17) is provided at an exit window (4) of the facetted light-collimator (2) or at an exit window of the facetted light-reflector (3).

12. An illumination system as claimed in claim 10, wherein the light-shaping diffuser (17) is a holographic diffuser.

13. An illumination system as claimed in claim 1, wherein the light emitters further comprise at least a third light-emitting diode (B) of a third primary color, the three primary colors being distinct from each other.

14. An illumination system as claimed in claim 1, wherein each of the light-emitting diodes (R, G, B) has a radiant power output of at least 25 mW when driven at nominal power and at room temperature.