LIGHT EMITTING DIODE MODULE WITH IMPROVED LIGHT DISTRIBUTION UNIFORMITY

• US 20070211473A1
• Filed: 03/09/2007
• Published: 09/13/2007
• Est. Priority Date: 03/10/2006
• Status: Active Grant

• Current Assignee: Dialight Corporation (Dialight PLC)
• Original Assignee: Dialight Corporation (Dialight PLC)
• Inventors: Peck, John Patrick
• Granted Patent: US 7,810,963 B2
• Time in Patent Office: Days
• US Class Current: 362/341
• CPC Class Codes: B61L 2207/02 using light-emitting diodes [LEDs]
• CPC Class Codes: B61L 5/1827 using light sources of different colours and a common optical system
• CPC Class Codes: B61L 5/1845 Optical systems, lenses
• CPC Class Codes: B61L 5/1854 Mounting and focussing of the light source in a lamp, fixing means
• CPC Class Codes: F21K 9/68 Details of reflectors forming part of the light source
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 5/008 Combination of two or more successive refractors along an optical axis
• CPC Class Codes: F21V 5/045 the lens having discontinuous faces, e.g. Fresnel lenses
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: F21W 2111/02 for roads, paths or the like
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

In one embodiment, the invention is a light emitting diode module with improved light distribution uniformity. One embodiment of a signal head includes a light emitting diode and a reflector cup positioned to reflect light emitted by the light emitting diode, the reflector cup having a non-symmetrical curvature.

Claims

1. A signal head, comprising:

a light emitting diode; and

a reflector cup positioned to reflect light emitted by the light emitting diode, the reflector cup having a non-symmetrical curvature.

2. The signal head of claim 1, further comprising:

a first lens for collimating the light reflected by the reflector cup; and

a second lens for distributing the light collimated by the first lens.

3. The signal head of claim 2, wherein the first lens is a Fresnel lens.

4. The signal head of claim 2, wherein the first lens and the second lens each have a diameter of approximately eight to twelve inches.

5. The signal head of claim 4, wherein a distance from the light emitting diode and the reflector cup to the first lens and the second lens is approximately three to four and one half inches.

6. The signal head of claim 1, wherein the reflector cup has a substantially conical shape.

7. The signal head of claim 6, wherein the substantially conical shape is one of:

a hyperbola, a parabola, an ellipse, a sphere, an oblate sphere or a modified conic.

8. The signal head of claim 6, wherein the substantially conical shape has a faceted surface.

9. The signal head of claim 1, wherein the substantially conical shape satisfies:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-\left(1+k\right)<br><br>c^2<br><br>r^2}}+F$ $r^2=x^2+y^2.$

10. The signal head of claim 1, wherein the reflector cup is formed of at least one of:

a metal, a metallized surface, a reflectorized surface, a plastic or a glass.

11. The signal head of claim 1, wherein a first section of a perimeter of the reflector cup has a slope that is at least five degrees greater than a slope of a second section of the perimeter.

12. A method for illuminating a signal head, the method comprising:

providing light via a light emitting diode; and

reflecting light emitted by the light emitting diode via a reflector cup, the reflector cup having a non-symmetrical curvature.

13. The method of claim 12, further comprising:

collimating the light reflected by the reflector cup using a first lens; and

distributing the light collimated by the first lens using a second lens.

14. The method of claim 13, wherein the first lens is a Fresnel lens.

15. The method of claim 13, wherein the first lens and the second lens each have a diameter of approximately eight to twelve inches.

16. The method of claim 15, wherein a distance from the light emitting diode and the reflector cup to the first lens and the second lens is approximately three to four and one half inches.

17. The method of claim 12, wherein the reflector cup has a substantially conical shape.

18. The method of claim 17, wherein the substantially conical shape is one of:

a hyperbola, a parabola, an ellipse, a sphere, an oblate sphere or a modified conic.

19. The method of claim 17, wherein the substantially conical shape has a faceted surface.

20. The method of claim 17, wherein the substantially conical shape satisfies:

$z=\frac{{\mathrm{cr}}^2}{1+\sqrt{1-\left(1+k\right)<br><br>c^2<br><br>r^2}}+F$ $r^2=x^2+y^2.$

21. The method of claim 12, wherein the reflector cup is formed of at least one of:

a metal, a metallized surface, a reflectorized surface, a plastic or a glass.

22. The method of claim 12, wherein a first section of a perimeter of the reflector cup has a slope that is at least five degrees greater than a slope of a second section of the perimeter.

23. A reflector optic for reflecting light emitted by an array of light-emitting diodes, the reflector optic comprising:

a reflective surface; and

a plurality of reflector cups formed in the reflective surface, each of the reflector cups having a non-symmetrical curvature designed to direct the emitted light away from a central axis.