Illumination system for spot illumination with reduced symmetry

• US 8,915,612 B2
• Filed: 06/11/2010
• Issued: 12/23/2014
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Kurt, Ralph, Tukker, Teunis Willem
• Primary Examiner(s): NEILS, PEGGY A
• Application Number:
  US13/378,718
• Publication Number:
  US 20120092864A1
• Time in Patent Office: 1,656 Days
• Field of Search: 362/243, 362/296.01, 362/341, 362/346, 362/348
• US Class Current: 362/243
• CPC Class Codes: F21K 9/62 using mixing chambers, e.g. housings with reflective walls
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An illumination system (1;30;40;60;70;90) for spot illumination comprising: a tubular reflector (3;31;61;91) with a reflective inner surface, the tubular reflector having an entrance aperture (9), and an exit aperture (10) being larger than the entrance aperture; and a light-source array (2;33;41;63;71;93) comprising a plurality of light-sources arranged in a physical light-source configuration to emit light into the tubular reflector at the entrance aperture thereof. The tubular reflector (3;31;61;91) comprises a plurality of reflective surfaces (14a-g) each being arranged to provide a primary mirror image of the light-source array, the primary mirror image having a primary mirror image light-source configuration; and the light-source array (2;33;41;63;71;93) is configured in such a way that, for each of the primary mirror image, at least half of all secondary mirror images of the light-source array resulting from reflection of the primary mirror image by the reflective surfaces (14a-g) exhibit secondary mirror image light-source configurations that are different from the physical light-source configuration.

Claims

1. An illumination system for spot illumination comprising:

a tubular reflector with a reflective inner surface, said tubular reflector having an entrance aperture, and an exit aperture being larger than the entrance aperture; and

a light-source array comprising a plurality of light-sources arranged in a physical light-source configuration to emit light into the tubular reflector at the entrance aperture thereof,

wherein said tubular reflector comprises an uneven number of reflective surfaces each being arranged to provide a primary mirror image of said light-source array, said primary mirror image having a primary mirror image light-source configuration; and

wherein said light-source array is configured in such a way that, for each of said primary mirror images, at least half of all secondary mirror images of said light-source array resulting from reflection of said primary mirror image by said reflective surfaces exhibit secondary mirror image light-source configurations that are different from said physical light-source configuration.

2. The illumination system according to claim 1, wherein said different secondary mirror image light-source configurations are different from said physical light-source configuration at least in respect of a rotational state thereof.

3. The illumination system according to claim 1, wherein said tubular reflector is configured in such a way that none of said reflective surfaces is parallel with respect to any other one of said reflective surfaces.

4. The illumination system according to claim 1, wherein said tubular reflector has an essentially polygonal cross-section.

5. The illumination system according to claim 1, wherein at least one of said reflective surfaces is curved.

6. The illumination system according to claim 1, wherein a section between said at least one reflective surface and a plane that is normal to an optical axis of said illumination system is a curved line.

7. The illumination system according to claim 1, wherein said tubular reflector is substantially trumpet-shaped.

8. The illumination system according to claim 1, wherein said physical light-source configuration is selected such that each rotational symmetry state of said light-source array is different from any rotational symmetry state of said tubular reflector.

9. The illumination system according to claim 8, wherein said tubular reflector exhibits a first number of rotational symmetry states having identical configurations, and said light-source array exhibits a second number of rotational symmetry states having identical configurations,

a ratio between said first number and said second number being a non-integer.

10. The illumination system according to claim 1, wherein a total area occupied by the light-sources comprised in said light-source array is equal to at least 5% of an area of said entrance aperture.

11. The illumination system according to claim 1, wherein said light-source array comprises at least one set of light-sources configured to emit light of a first color and at least one set of light-sources configured to emit light of a second color different from the first color.

12. The illumination system according to claim 11,

wherein said light-source array comprises at least three sets of light-sources configured to emit light of said first color and at least three sets of light-sources configured to emit light of said second color;

and

wherein a largest spacing between neighboring ones of said sets of light-sources is smaller than a third of a lateral extension of said entrance aperture.

13. The illumination system according to claim 1, further comprising a light-diffusing optical member arranged to diffuse light output by said illumination system.

14. The illumination system according to claim 1, further comprising a focusing optical element arranged to focus light output by said illumination system.