Luminaire having a reflector for mixing light from a multi-color array of leds

• US 6,200,002 B1
• Filed: 03/26/1999
• Issued: 03/13/2001
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Original Assignee: Philips Electronics North America Corporation (Koninklijke Philips N.V.)
• Inventors: Shimizu, Jeffrey A., Pashley, Michael D., Herman, Stephen, Marshall, Thomas M.
• Primary Examiner(s): Sember, Thomas M.
• Application Number:
  US09/277,645
• Time in Patent Office: 718 Days
• Field of Search: 362/551, 362/555, 362/583, 362/230, 362/231, 362/235, 362/293, 362/296
• US Class Current: 362/231
• CPC Class Codes: F21S 10/02 changing colors F21S10/002 - F21S10/007, F21S10/04 take precedence
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2105/12 characterised by the geometrical disposition of the light-generating elements, e.g. arranging light-generating elements in differing patterns or densities
• 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: G02F 1/133605 including specially adapted reflectors

Abstract

A light source includes an array of LEDs in each of a plurality colors such as red, green, and blue in the entrance aperture of a tubular reflector which preferably has convex walls facing the optic axis and flares outward toward the exit aperture, and preferably has a polygonal cross section such as a square. Mixing of colors is further promoted by utilizing a large number of small LEDs with the LEDs of each color being centered on the optic axis.

Claims

1. A light source comprising:

an array of LEDs arranged in a hexagonal array and comprising at least one LED in each of a plurality of colors for emitting light in each of a plurality of colors, wherein the array of LEds comprises green, red and blue LEDs and the number of green LEDs is greater than the number of red LEDs which is greater than the number of blue LEDs, and

a reflecting tube having an entrance aperture, an exit aperture, a reflective circumferential wall extending between said apertures, and an optic axis extending between said apertures centrally of said wall, said array of LEDs being arranged in said entrance aperture, said circumferential wall being arranged to reflect and mix light from said array of LEDs.

2. A light source as in claim 1 wherein said circumferential wall has a cross section transverse to said optic axis, said cross-section being substantially non-round along at least a part of said optic axis.

3. A light source as in claim 2 wherein said cross-section is polygonal, said circumferential wall comprising a plurality of sidewalls which are substantially straight in said cross section.

4. A light source as in claim 3 wherein said cross section is square.

5. A light source as in claim 3 wherein said cross-section is octagonal.

6. A light source as in claim 1 wherein said circumferential wall diverges from said entrance aperture to said exit aperture.

7. A light source as in claim 6 wherein said circumferential wall, seen from said optic axis, has a convex shape.

8. A light source as in claim 7 wherein said circumferential wall flares outward toward said exit aperture.

9. A light source as in claim 1 wherein the LEDs in each color define a color distribution having a center of gravity lying on the optic axis.

10. A light source as in claim 9 wherein each color distribution has the same mean radial distance from the optic axis.

11. A light source as in claim 1 further comprising a diffusive cover on the exit aperture.

12. A light source as in claim 1 wherein said reflective circumferential wall is made of a specular-plus-diffuse reflecting material.

13. A light source as claimed in claim 1 wherein the number of LEDs present in said array of LEDs of at least one of said plurality of colors is different from the number of LEDs of at least one other of said plurality of colors.

14. A light source as claimed in claim 1, wherein the green, red and blue LEDs are present in the ratio of colors R:

G;

B=2;

3;

1.

15. A light source as claimed in claim 1 further comprising means for controlling the intensity of light emitted by said LEDs and controlling the color temperature thereof throughout the range of light intensity control.

16. A light source comprising:

an array of LEDs comprising at least one LED in each of a plurality of colors for emitting light in each of a plurality of colors, and

a reflecting tube having an entrance aperture, an exit aperture, a reflective circumferental wall extending between said apertures, and an optic axis extending between said apertures centrally of said wall, said array of LEDs being arranged in said entrance aperture, said circumferential wall being arranged to reflect and mix light from said array of LEDs, wherein said circumferential wall has a square cross-section transverse to said optic axis, and wherein the array of LEDs comprises green, red and blue LEDs arranged in a square array and present in the ratio of colors R;

G;

B=1;

2;

1.

17. A light source comprising:

an array of LEDs comprising at least one LED in each of a plurality of colors for emitting light in each of a plurality of colors, and

a reflecting tube having an entrance aperture, an exit aperture, a reflective circumferential wall extending between said apertures, and an optic axis extending between said apertures centrally of said wall, said array of LEDs being arranged in said entrance aperture, said circumferential wall being arranged to reflect and mix light from said array of LEDs, wherein said circumferential wall has an octagonal cross-section transverse to said optic axis, and wherein the array of LEDs comprises green, red and blue LEDs arranged in a square array and present in the ratio of colors R;

G;

B=1;

2;

1.

18. A light source comprising:

an array of LEDs comprising at least one LED in each of a plurality of colors for emitting light in each of a plurality of colors, and

a reflecting tube having an entrance aperture, an exit aperture, a reflective circumferential wall extending between said apertures, and an optic axis extending between said apertures centrally of said wall, said array of LEDs being arranged in said entrance aperture, said circumferential wall being arranged to reflect and mix light from said array of LEDs, wherein said circumferential wall has a cross section transverse to said optic axis, said cross-section being substantially non-round along at least a part of said optic axis, and wherein said circumferential wall comprises at least two approximately parallel walls adjacent the entrance aperture and which flare outward toward said exit aperture.

19. A light source comprising:

an array of LEDs comprising at least one LED in each of a plurality of colors for emitting light in each of a plurality of colors, and

a reflecting tube having an entrance aperture, an exit aperture, a reflective circumferental wall extending between said apertures, and an optic axis extending between said apertures centrally of said wall, said array of LEDs being arranged in said entrance aperture, said circumferential wall being arranged to reflect and mix light from said array of LEDs, wherein said circumferential wall has a cross section transverse to said optic axis, said cross-section being substantially non-round along at least a part of said optic axis, and wherein said cross-section is a polygonal along substantially the entire length of the optic axis and said circumferential wall diverges from said entrance aperture to said exit aperture such that the exit aperture is larger than the entrance aperture.