ILLUMINATION SYSTEM FOR SPOT ILLUMINATION WITH REDUCED SYMMETRY

• US 20120092864A1
• Filed: 06/11/2010
• Published: 04/19/2012
• Est. Priority Date: 06/16/2009
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kurt, Ralph, Tukker, Teunis Willem
• Granted Patent: US 8,915,612 B2
• Time in Patent Office: Days
• US Class Current: 362/231
• 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 (1;

30;

40;

60;

70;

90) for spot illumination comprising;

a tubular reflector (3;

31;

61;

91) with a reflective inner surface, said 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,

wherein said tubular reflector (3;

31;

61;

91) comprises a plurality of reflective surfaces (14a-g) 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 (2;

33;

41;

63;

71;

93) 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 (14a-g) exhibit secondary mirror image light-source configurations that are different from said physical light-source configuration.

2. The illumination system (1;

30;

40;

60;

70;

90) 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 (1;

30;

40;

60;

70) according to claim 1, wherein said tubular reflector (3;

31;

61) 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 (1;

30;

40;

60;

70) according to claim 1, wherein said tubular reflector (3;

31;

61) comprises an uneven number of reflective surfaces.

5. The illumination system (1;

30;

40;

60;

70;

90) according to claim 1, wherein said tubular reflector (3;

31;

61;

91) has an essentially polygonal cross-section.

6. The illumination system (1;

30;

40;

60;

70;

90) according to claim 1, wherein at least one of said reflective surfaces is curved.

7. 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.

8. The illumination system (1;

30;

40;

60;

70;

90) according to claim 1, wherein said tubular reflector is substantially trumpet-shaped.

9. The illumination system (1;

30;

40;

60;

70;

90) 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.

10. The illumination system (1;

30;

40;

60;

70;

90) according to claim 9, 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.

11. The illumination system (1;

30;

40;

60;

70;

90) 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.

12. The illumination system (1;

30;

40;

60;

70;

90) 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.

13. The illumination system (1;

30;

40;

60;

70;

90) according to claim 12,

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.

14. The illumination system (1;

30;

40;

60;

70;

90) according to claim 1, further comprising a light-diffusing optical member (11) arranged to diffuse light output by said illumination system (1;

30;

40;

60;

70;

90).

15. The illumination system (1;

30;

40;

60;

70;

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