Optical system with reflectors and light pipes

• US 8,297,818 B2
• Filed: 06/11/2009
• Issued: 10/30/2012
• Est. Priority Date: 06/11/2009
• Status: Expired due to Fees

• Current Assignee: Rambus Delaware LLC (Rambus Inc.)
• Original Assignee: Rambus International Ltd (Rambus Inc.)
• Inventors: Richardson, Brian Edward
• Primary Examiner(s): Allen, Danielle
• Application Number:
  US12/456,123
• Publication Number:
  US 20100220492A1
• Time in Patent Office: 1,237 Days
• Field of Search: 362341-361, 362/551, 362/555, 362/558, 362/227, 362/230, 362/231, 362/241, 362/243, 362/245, 362/247, 362/249.02, 362/296.01, 362/297, 362/301, 362/311.01, 362/311.02, 362/327, 362/328, 362/612, 362/613, 362/623, 362/331, 362606-607, 362615-620
• US Class Current: 362/551
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0075 Arrangements of multiple light guides G02B6/0028 takes precedence

Abstract

An optical system utilizing a light pipe in which light travels by total internal reflection (TIR) accurately controls the light exiting the pipe. The system achieves accurate control of the reflected light by selectively extracting light from a limited area of the light pipe. The configuration of the reflectors used for the selective extraction of the light determines the nature of the output light. The reflectors are preferably located on an output side of the light pipe. All light output by the system is directed by the reflectors.

Claims

1. An optical system comprising:

a light source;

a light pipe along which light from the light source travels by total internal reflection; and

a light extracting and reflecting member comprising a light extractor in contact with the light pipe to provide selective extraction of light from the light pipe, and a reflector positioned outside the light pipe, the reflector configured to direct light extracted from the light pipe by the light extractor away from the light pipe.

2. The optical system of claim 1, wherein the light pipe has a reduction in thickness from a first end at which the light source is located, the reduction in thickness being accomplished by a notch that receives the light extracting and reflecting member.

3. The optical system of claim 1, wherein the light pipe has a tapered reduction in thickness from a first end at which the light source is located.

4. The optical system of claim 1, wherein the reflector controls the direction of output light in one dimension.

5. The optical system of claim 1, wherein the reflector controls the direction of output light in two dimensions.

6. The optical system of claim 1, wherein the light extracting and reflecting member is one of multiple light extracting and reflecting members disposed along the light pipe.

7. The optical system of claim 1, wherein the light source is one of multiple light sources employed to provide light to the light pipe.

14. The optical system of claim 1, wherein the light pipe comprises a notch and the light extractor of the light extracting and reflecting member is in contact with the light pipe at the notch.

15. The optical system of claim 1, wherein the light pipe is one of an array of light pipes arranged in a plane, and the light extracting and reflecting member is one of an array of light extracting and reflecting members arranged non-parallel to the light pipes, each of the light extracting and reflecting members comprising a respective light extractor in contact with each of the light pipes to selectively extract light from the light pipes.

8. An optical system comprising:

a light source comprising a plurality of LEDs;

a light pipe along which light from the light source travels by total internal reflection; and

a light extracting and reflecting member comprising a light extractor in contact with the light pipe to provide selective extraction of light from the light pipe, and a reflector positioned outside the light pipe, the reflector configured to direct light extracted from the light pipe by the light extractor away from the light pipe.

9. The optical system of claim 8, wherein the light pipe has a reduction in thickness from a first end at which the light source is located, the reduction in thickness being accomplished by a notch that receives the light extracting and reflecting member.

10. The optical system of claim 8, wherein the light pipe has a tapered reduction in thickness from a first end at which the light source is located.

11. The optical system of claim 8, wherein the reflector controls the direction of output light in one dimension.

12. The optical system of claim 8, wherein the reflector controls the direction of output light in two dimensions.

13. The optical system of claim 8, wherein the light extracting and reflecting member is one of multiple light extracting and reflecting members disposed along the light pipe.

16. The optical system of claim 8, wherein the light pipe comprises a notch and the light extractor of the light extracting and reflecting member is in contact with the light pipe at the notch.

17. The optical system of claim 8, wherein the light pipe is one of an array of light pipes arranged in a plane, and the light extracting and reflecting member is one of an array of light extracting and reflecting members arranged non-parallel to the light pipes, each of the light extracting and reflecting members comprising a respective light extractor in contact with each of the light pipes to selectively extract light from the light pipes.

18. An optical system, comprising:

an array of light pipes arranged in a plane, each of the light pipes comprising a light input surface at an end thereof, and a side surface comprising steps disposed along a length thereof such that the light pipe decreases in thickness with increasing distance from the light input surface;

a respective light source adjacent the light input surface of each of the light pipes; and

an array of light extracting and reflecting members arranged non-parallel to the light pipes, each of the light extracting and reflecting members comprising;

a light extractor in contact with a respective step of the light pipes to selectively extract light from the light pipes, and

a reflector to direct light extracted from the light pipes by the light extractor away from the light pipes.