DISPLAY DEVICE WITH DIFFRACTIVE OPTICS

• US 20100103488A1
• Filed: 10/09/2007
• Published: 04/29/2010
• Est. Priority Date: 10/10/2006
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Mienko, Marek, Xu, Gang, Bita, Ion, Gruhlke, Russell Wayne
• Application Number:
  US12/444,683
• Publication Number:
  US 20100103488A1
• Time in Patent Office: Days
• US Class Current: 359/15
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G03H 2001/0419 for recording combined transmission and reflection holograms
• CPC Class Codes: G03H 2001/2228 adapted for reflection and transmission reconstruction

Abstract

Light modulator displays may be illuminated using a light guide comprising diffractive optics that directs light onto an array of light modulators. A holographic light turning element may be included with the light guide to turn light propagating within the light guide onto the light modulators. In some embodiments, the holographic element is configured to distribute a substantially uniform amount of light across the array of modulators. The holographic element may, for example, have a turning efficiency that changes along the length of the holographic element. A holographic element can also be used to function as a light bar. Such a holographic element may receive light from a light source such as a light emitting diode and distribute the light along a light guide disposed in front of an array of light modulators.

Claims

1. An illumination apparatus comprising:

a light guide having first and second ends, such that light injected into said first end is guided toward said second end via total internal reflection; and

diffractive optics disposed to receive light propagating within the light guide and turn a portion of said light out of said light guide, said diffractive optics having a turning efficiency that determines the amount of light turned out of the light guide compared to the amount of light that continues to be guided within the light guide,

wherein said diffractive optics comprises at least one hologram, and wherein the turning efficiency increases across a substantial portion of said light guide, the turning efficiency increasing by increasing a range of acceptance angles of the at least one hologram.

2. The apparatus of claim 1, wherein the at least one hologram comprises a surface or volume hologram.

4. The apparatus of claim 1, wherein the turning efficiency increases on average over said substantial portion of said light guide.

5. The apparatus of claim 2, wherein the power of the light exiting the light guide is substantially the same along said substantial portion of said light guide.

6. The apparatus of claim 1, wherein said substantial portion comprises over at least 50% of the distance between the first end and the second end.

11. The apparatus of claim 1, wherein the at least one hologram is computer generated or is produced via replication from a computer generated master hologram.

12. The apparatus of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

13. The apparatus of claim 12, further comprising a driver circuit configured to send at least one signal to the display.

14. The apparatus of claim 13, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

15. The apparatus of claim 12, further comprising an image source module configured to send said image data to said processor.

16. The apparatus of claim 15, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

17. The apparatus of claim 12, further comprising an input device configured to receive input data and to communicate said input data to said processor.

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18. A method of manufacturing an illumination apparatus, the method comprising:

providing a light guide having first and second ends such that light injected into said first end is guided toward said second end via total internal reflection; and

disposing diffractive optics so as to receive light guided in said light guide and turn a portion of the light out of said light guide, said diffractive optics having a turning efficiency that determines the amount of light turned out of the light guide compared to the amount of light that continues to be guided within the light guide,

wherein said diffractive optics comprises at least one hologram, and wherein the turning efficiency of said hologram increases across a substantial portion of said light guide, the turning efficiency increasing by increasing a range of acceptance angles of the at least one hologram.

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28. An illumination apparatus comprising:

means for guiding light, said light guiding means having first and second ends such that light injected into said first end is guided toward said second end; and

means for diffracting and turning a portion of said light out of said light guide, said diffracting means having a turning efficiency that determines the amount of light turned out of the light guide compared to the amount of light that continues to be guided within the light guide,

wherein said diffracting means turns said light holographically, and wherein the turning efficiency increases across a substantial portion of said guiding means by increasing a range of acceptance angles of the diffracting and turning means.

29. The apparatus of claim 28, wherein said light guiding means comprise a light guide or said diffracting means comprises at least one hologram.

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32. A method of manufacturing an illumination apparatus, the method comprising:

providing a light guide having first and second ends such that light injected into said first end is guided toward said second end via total internal reflection; and

disposing holographic features in a holographic medium with respect to said light guide so as to receive light guided in said light guide and turn a portion of the light out of said light guide, wherein said holographic features are substantially the same as holographic features formed by a recording process using a beam having a width, wherein a gradient in intensity of said beam varies across the width.

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35. An illumination apparatus comprising:

a light guide having first and second ends, such that light injected into said first end is guided toward said second end via total internal reflection; and

diffractive optics comprising first and second holograms disposed in first and second layers, said diffractive optics disposed to receive light propagating within the light guide and turn a portion of said light out of said light guide, said diffractive optics having a turning efficiency that determines the amount of light turned out of the light guide compared to the amount of light that continues to be guided within the light guide,

wherein the turning efficiency varies across a substantial portion of said light guide, and wherein the turning efficiency of each of said first and second holograms is substantially constant over a substantial portion thereof, and said first and second holograms are arranged to provide increasing turning efficiency across the light guide.

36. The apparatus of claim 35, wherein said substantial portion of said holographic layer comprises over at least 50% of the holographic layer.

37. A method of manufacturing an illumination apparatus, the method comprising:

providing a light guide having first and second ends such that light injected into said first end is guided toward said second end via total internal reflection; and

disposing diffractive optics comprising first and second holograms disposed in first and second layers, respectively, so as to receive light guided in said light guide and turn a portion of the light out of said light guide, said diffractive optics having a turning efficiency that determines the amount of light turned out of the light guide compared to the amount of light that continues to be guided within the light guide,

wherein the turning efficiency varies across a substantial portion of said light guide, and wherein the turning efficiency of each of said first and second holograms is substantially constant over a substantial portion thereof, and said first and second holograms are arranged to provide increasing turning efficiency across the light guide.

38. The method of claim 37, wherein said substantial portion of said holographic layer comprises over at least 50% of the holographic layer.

39. An illumination apparatus comprising:

a light guide having a top and bottom and edges disposed about said top and bottom; and

diffractive optics configured to receive light propagating from a first edge of said light guide toward a second edge and turn at least a portion of the received light such that said light is redirected toward a third edge of said light guide, said diffractive optics comprising at least one hologram.

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57. A method of manufacturing an illumination apparatus, the method comprising:

providing a light guide having a top and bottom and edges disposed about said top and bottom; and

disposing diffractive optics to receive light propagating from a first edge of said light guide to a second edge and turn at least a portion of the received light such that said light is redirected toward a third edge of said light guide, said diffractive optics comprising at least one hologram.

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69. An illumination apparatus comprising:

a means for guiding light, said means having a top and bottom and edges disposed about said top and bottom, such that light injected in a first edge of said light guiding means propagates toward a second edge of said light guiding means; and

means for diffractive and turning light, said diffractive means configured to receive light propagating from said first edge to said second edge and turn at least a portion of the received light such that said light is redirected toward a third edge of said light guiding means, said diffractive means configured to turn light holographically.

70. The apparatus of claim 69, wherein said light guiding means comprises a light guide or said diffractive means comprises at least one hologram.

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