Multibeam diffraction grating-based backlighting

• US 9,128,226 B2
• Filed: 06/18/2014
• Issued: 09/08/2015
• Est. Priority Date: 07/30/2013
• Status: Active Grant

• Current Assignee: LEIA SPV LLC
• Original Assignee: Leia Inc.
• Inventors: Fattal, David A., Peng, Zhen, Santori, Charles M.
• Primary Examiner(s): Vu, Phu
• Application Number:
  US14/308,689
• Publication Number:
  US 20150036068A1
• Time in Patent Office: 447 Days
• Field of Search: 349/65
• US Class Current: 1/1
• CPC Class Codes: G02B 30/27 involving lenticular arrays
• CPC Class Codes: G02B 30/33 involving directional light or back-light sources
• CPC Class Codes: G02B 5/1861 Reflection gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 5/1866 Transmission gratings characterised by their structure, e.g. step profile, contours of substrate or grooves, pitch variations, materials G02B5/1809, G02B5/1828, G02B5/1833, G02B5/1838 and G02B5/1847 take precedence
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

Multibeam diffraction grating-based backlighting includes a light guide and a multibeam diffraction grating at a surface of the light guide. The light guide is to guide light from a light source. The multibeam diffraction grating is to couple out a portion of the guided light using diffractive coupling and to direct the coupled out portion away from the light guide as a plurality of light beams with different principal angular directions.

Claims

1. A multibeam diffraction grating-based backlight comprising:

a light guide to guide light from a light source;

a multibeam diffraction grating at a surface of the light guide, the multibeam diffraction grating to couple out a portion of the guided light using diffractive coupling, the coupled out portion of the guided light being directed away from the light guide surface as a plurality of light beams, a light beam of the plurality having a different principal angular direction from other light beams of the plurality.

2. The multibeam diffraction grating-based backlight of claim 1, wherein the multibeam diffraction grating comprises a chirped diffraction grating.

3. The multibeam diffraction grating-based backlight of claim 2, wherein the chirped diffraction grating is a linearly chirped diffraction grating.

4. The multibeam diffraction grating-based backlight of claim 1, wherein the multibeam diffraction grating comprises one of curved grooves and curved ridges that are spaced apart from one another.

5. The multibeam diffraction grating-based backlight of claim 1, further comprising the light source at an edge of the light guide, the guided light being light from the light source that is coupled into the edge of the light guide.

6. The multibeam diffraction grating-based backlight of claim 1, wherein the light guide and the multibeam diffraction grating are substantially transparent in a direction orthogonal to a direction in which the light is to be guided in the light guide.

7. An electronic display comprising the multibeam diffraction grating-based backlight of claim 1, wherein the portion of the guided light to be coupled out by the multibeam diffraction grating is light corresponding to a pixel of the electronic display.

8. The electronic display of claim 7, further comprising a light valve to modulate the light beam of the plurality of light beams, the multibeam diffraction grating being between the light valve and the light guide surface.

16. The multibeam diffraction grating-based backlight of claim 1, wherein the multibeam diffraction grating comprises a chirped diffraction grating having curved diffractive features, a curve of the curved diffractive features to partially define the different principal angular direction of the light beam of the plurality.

17. The multibeam diffraction grating-based backlight of claim 1, wherein the light beams of the plurality have different principal angular directions configured to form pixels corresponding to different views of a 3-D electronic display.

9. A three-dimensional (3-D) electronic display comprising:

a plate light guide to guide light from a light source;

a multibeam diffraction grating to couple out a portion of the guided light as a plurality of light beams and to direct the light beams in a corresponding plurality of different principal angular directions; and

a light valve array to modulate the differently directed light beams of the plurality,

wherein the plurality of modulated, differently directed, light beams represents pixels of the 3-D electronic display, different ones of the modulated differently directed light beams corresponding to different views of the 3-D electronic display.

10. The 3-D electronic display of claim 9, wherein the multibeam diffraction grating comprises a chirped diffraction grating having curved diffractive features.

11. The 3-D electronic display of claim 9, wherein the light valve array comprises a plurality of liquid crystal light valves.

12. The 3-D electronic display of claim 11, wherein the light valve array has a thickness of greater than about 100 micrometers.

13. The 3-D electronic display of claim 9, further comprising the light source, the guided light being light from the light source that is coupled into the edge of the plate light guide.

14. A method of electronic display operation, the method comprising:

guiding light in a light guide;

diffractively coupling out a portion of the guided light using a multibeam diffraction grating at a surface of the light guide to produce a plurality of light beams; and

directing the plurality of light beams away from the light guide surface,

wherein a light beam of the plurality has a different principal angular direction from other light beams of the plurality.

15. The method of electronic display operation of claim 14, further comprising modulating the plurality of light beams using a corresponding plurality of light valves, the modulated light beams forming pixels of a three-dimensional (3-D) electronic display.