Display device with diffractive optics

• US 8,368,981 B2
• Filed: 04/06/2009
• Issued: 02/05/2013
• Est. Priority Date: 10/10/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gruhlke, Russell Wayne, Bita, Ion, Mienko, Marek, Xu, Gang
• Primary Examiner(s): Doak, Jennifer L.
• Application Number:
  US12/419,263
• Publication Number:
  US 20090251752A1
• Time in Patent Office: 1,401 Days
• Field of Search: 359/15, 359/28, 359/34, 362551-582, 385/37
• 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 the light modulators. The light guide may comprise, for example, a holographic light turning element that turns light propagating within the light guide onto the array of light modulators. In some embodiments, the holographic element has multiple holographic functions. For example, the holographic element may additionally collimate ambient light or diffuse light reflected form the light modulators.

Claims

1. An illumination apparatus having front and rear surfaces, the illumination apparatus comprising:

a plurality of holographic features between the front and rear surfaces, the front surface being forward the holographic features and the rear surface being rearward the holographic features;

a first light guide forward the holographic features, wherein a largest surface of the first light guide faces the front surface; and

a second light guide rearward the holographic features, the first and second light guides each configured to guide light therein,

wherein the holographic features are disposed between the first light guide and the second light guide, and

wherein the holographic features are configured to turn at least a portion of the light from each of the first and second light guides, such that the turned portions of light exit the apparatus through the rear surface.

2. The illumination apparatus of claim 1, wherein said holographic features are disposed in a holographic layer.

3. The illumination apparatus of claim 2, wherein said holographic layer forms an optical isolation layer for the first and second light guides.

4. The illumination apparatus of claim 1, wherein said holographic features comprise volume or surface features.

5. The illumination apparatus of claim 1, further comprising a plurality of display elements disposed rearward of said rear surface.

6. The illumination apparatus of claim 5, wherein the plurality of display elements comprises a plurality of interferometric modulators.

7. The illumination apparatus of claim 1, wherein the holographic features are further configured to collect ambient light incident thereon, and to collimate said collected light.

8. The illumination apparatus of claim 1, wherein the holographic features are further configured to diffuse light propagating from the rear surface.

9. The illumination apparatus of claim 8, wherein the holographic features are further configured to collect ambient light incident thereon, and to collimate said collected light.

10. The illumination 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.

11. The illumination apparatus of claim 10, further comprising a driver circuit configured to send at least one signal to the display.

12. The illumination apparatus of claim 11, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

13. The illumination apparatus of claim 10, further comprising an image source module configured to send said image data to said processor.

14. The illumination apparatus of claim 13, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

15. The illumination apparatus of claim 10, further comprising an input device configured to receive input data and to communicate said input data to said processor.

16. The illumination apparatus of claim 1, wherein the holographic features are configured such that the turned portion of light from the first light guide propagates through the holographic features into the second light guide, and further configured such that the turned portion of light from the second light guide is redirected towards the rear surface and prevented from propagating into the first light guide.

17. An illumination apparatus having front and rear surfaces, the illumination apparatus comprising:

holographic means for diffracting light between the front and rear surfaces, the front surface being forward the diffracting means and the rear surface being rearward the diffracting means;

first means for guiding light disposed forward the diffracting means, wherein a largest surface of the first light guiding means faces the front surface; and

second means for guiding light disposed rearward the diffracting means, the first and second light guiding means each configured to guide light therein,

wherein the holographic means are disposed between the first light guiding means and the second light guiding means, and

wherein the diffracting means are configured to turn at least a portion of the light from each of the first and second light guiding means, such that the turned portions of light exit the apparatus through the rear surface.

18. A method of manufacturing an illumination apparatus having front and rear surfaces, the method comprising:

disposing a plurality of holographic features between the front and rear surfaces, the front surface being forward the holographic features and the rear surface being rearward the holographic features;

disposing a first light guide forward the holographic features, such that a largest surface of the first light guide faces the front surface; and

disposing a second light guide rearward the holographic features, the first and second light guides each configured to guide light therein, such that the holographic features are disposed between the first light guide and the second light guide,

wherein the holographic features are configured to turn at least a portion of the light from each of the first and second light guides, such that the turned portions of light exit the apparatus through the rear surface.

19. A method of using a multilayer stack having front and rear surfaces, the method comprising:

guiding light in a first light guide forward a plurality of holographic features, the holographic features between the front and rear surfaces, the front surface being forward the holographic features and the rear surface being rearward the holographic features;

guiding light in a second light guide rearward the holographic features, wherein a largest surface of the first light guide faces the front surface, and wherein the holographic features are disposed between the first light guide and the second light guide; and

with the holographic features, turning at least a portion of the light from each of the first and second light guides, such that the turned portions of light exit the apparatus through the rear surface.

20. An apparatus having front and rear surfaces, the 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, wherein a largest surface of the light guide faces the front surface; and

diffractive optics disposed to receive light guided within the light guide and configured to turn a portion of said guided light out of said light guide, said diffractive optics further configured to collect ambient light incident thereon and collimate said ambient light,

wherein said diffractive, optics comprises at least one holographic element.

21. An apparatus having front and rear surfaces, the apparatus comprising:

means for guiding light having first and second ends, such that light injected into said first end is guided toward said second end via total internal reflection, wherein a largest surface of the light guiding means faces the front surface; and

means for diffracting light disposed to receive light guided within the light guiding means and configured to turn a portion of said guided light out of said light guiding means, said light diffracting means further configured to collimate ambient light incident thereon,

wherein said light diffracting means diffracts light holographically.

22. A method of manufacturing an illumination apparatus having front and rear surfaces, 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, wherein a largest surface of the light guide faces the front surface; and

disposing diffractive optics to receive light guided within the light guide and configured to turn a portion of said guided light out of said light guide, said diffractive optics further configured to collimate said ambient light,

wherein said diffractive optics comprises at least one holographic element.

23. An illumination apparatus having front and rear surfaces, the apparatus comprising:

a light guide having first and second ends and forward and rearward surfaces, the light guide adapted such that light injected into said first end is guided between said forward and rearward surfaces toward said second end via total internal reflection, wherein the forward surface of the light guide faces the front surface of the apparatus; and

diffractive optics disposed to receive light guided within the light guide and configured to turn a portion of said guided light out of said light guide through said rearward surface, said diffractive optics further configured to diffuse light that enters said light guide through said rearward surface and exits said light guide through said forward surface,

wherein said diffractive optics comprises at least one holographic element.

24. An illumination apparatus having front and rear surfaces, the apparatus comprising:

means for guiding light having first and second ends and forward and rearward surfaces, the light guiding means adapted such that light injected into said first end is guided between said forward and rearward surfaces toward said second end via total internal reflection, wherein the forward surface of the light guide faces the front surface of the apparatus; and

means for diffracting light, the diffracting means configured to receive light guided within the light guiding means and turn a portion of said guided light out of said light guiding means through said rearward surface, said light diffracting means further configured to diffuse light that enters said light guiding means through said rearward surface and exits said light guiding means through said forward surface,

wherein said light diffracting means diffracts light holographically.

25. A method of manufacturing an illumination apparatus having front and rear surfaces, the method comprising:

providing a light guide having first and second ends and forward and rearward surfaces, the light guide adapted such that light injected into said first end is guided between said forward and rearward surfaces toward said second end via total internal reflection, wherein the forward surface of the light guide faces the front surface of the apparatus; and

disposing diffractive optics to receive light guided within the light guide and turn a portion of said guided light out of said light guide through said rearward surface, said diffractive optics configured to diffuse light that enters said light guide through said rearward surface and exits said light guide through said forward surface,

wherein said diffractive optics comprises at least one holographic element.