Illumination device having a tapered light guide

Patent metadata

Field	Value
Publication number	US-9448353-B2
Application number	US-201514627460-A
Country	US
Kind code	B2
Filing date	Feb 20, 2015
Priority date	Jan 30, 2008
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

This disclosure provides systems, methods and apparatus for illumination devices. In one aspect, an illumination device having a longitudinal axis includes a light source and a light guide. The light guide has a peripheral edge, a transmissive illumination surface, a center portion, and an upper surface. The transmissive illumination surface is oriented perpendicular to the longitudinal axis and disposed between the center portion and the peripheral edge. The upper surface is oriented relative to the illumination surface to define an angle α therebetween. In some implementations, the angle α can be greater than 15 degrees, for example.

First claim

What is claimed is:

1. An illumination device, comprising:
a light source;
a tapered light guide including
a light input surface on an end of the light guide,
a light output surface extending away from the light input surface along a plane at an angle to the light input surface, and
an inclined surface opposite the light output surface, the inclined surface being at an angle α, with respect to the light output surface, of less than 15 degrees, the light source and the tapered light guide aligned such that light emitted from the light source propagates into the light guide through the input edge surface and exits the light guide through the light output surface;

an optical layer coupled to the light output surface of the light guide, the optical layer including at least one light redirecting element; and
a light reflecting layer adjacent to the inclined surface such that the inclined surface is located between the light reflecting surface and the light output surface, wherein the light reflecting layer is configured to reflect the light emitted from the light source towards the light output surface into the tapered light guide.

2. The illumination device of claim 1 , wherein the light reflecting layer is spaced apart from the inclined surface by a gap.

3. The illumination device of claim 2 , wherein the gap includes air.

4. The illumination device of claim 2 , wherein the gap includes a dielectric.

5. The illumination device of claim 2 , wherein the gap includes a material having an index of refraction that is less than an index of refraction of the light guide.

6. The illumination device of claim 1 , wherein, light exiting the light guide through the light output surface is collimated and the optical layer is configured to redirect light exiting the light output surface along a desired direction.

7. The illumination device of claim 1 , further comprising a light coupling system between the light source and the light input surface.

8. The illumination device of claim 7 , wherein the light coupling system includes an angle transforming reflector.

9. The illumination device of claim 7 , wherein the light coupling system includes an etendue preserving reflector.

10. The illumination device of claim 7 , wherein the light coupling system includes a curved reflector.

11. The illumination device of claim 7 , wherein the light coupling system includes a light guiding pipe.

12. The device of claim 1 , wherein the light source includes one or more light emitting diodes (LEDs).

13. The device of claim 1 , wherein the light source includes an array of LEDs.

14. A method of manufacturing an illumination device, the method comprising:
providing a light source;
providing a tapered light guide including
a light input surface on an end of the light guide,
a light output surface extending away from the light input surface along a plane at an angle to the light input surface, the light guide configured such that light propagating in the light guide exits through the light output surface; and
an inclined surface opposite the light output surface, the inclined surface being at an angle α with respect to the light output surface of less than 15 degrees;

aligning the light source and the tapered light guide such that light emitted from the light source propagates into the light guide through the input edge surface;
coupling an optical layer to the light output surface of the light guide, the optical layer including at least one light redirecting element; and
providing a light reflecting layer adjacent the inclined surface, wherein the light reflecting layer is configured to reflect the light emitted from the light source to the light output surface into the tapered light guide.

15. The method of claim 14 , further comprising providing a light coupling system between the light source and the light input surface.

16. The method of claim 15 , wherein the light coupling system includes an angle transforming reflector.

17. The method of claim 15 , wherein the light coupling system includes an etendue preserving reflector.

18. The method of claim 15 , wherein the light coupling system includes a curved reflector.

19. The method of claim 14 , wherein the light source includes one or more light emitting diodes (LEDs).

20. The method of claim 14 , wherein the light reflecting layer is spaced apart from the inclined surface by a gap.

21. The device of claim 1 , wherein the light reflecting layer is parallel to the inclined surface.

Assignees

• Qualcomm Mems Technologies Inc

Inventors

• Holman Robert Louis
• Sampsell Matthew Brian

Classifications

• F21Y2115/10

  Light-emitting diodes [LED] · CPC title

• G02B6/0085

  Means for removing heat created by the light source from the package · CPC title

• G02B6/0055

  Reflecting element, sheet or layer · CPC title

• G02B6/0046

  Tapered light guide, e.g. wedge-shaped light guide · CPC title

• G02B6/0016

  Grooves, prisms, gratings, scattering particles or rough surfaces · CPC title