Display panel with electrically-controlled waveguide-routing

• US 5,544,268 A
• Filed: 09/09/1994
• Issued: 08/06/1996
• Est. Priority Date: 09/09/1994
• Status: Expired due to Term

• Current Assignee: Gemfire Corp. (Medtronic Plc)
• Original Assignee: Deacon Research
• Inventors: Bischel, William K., Field, Simon J., Dyer, Mark J., Brinkman, Michael J., Deacon, David A. G., DeWath, Edward J.
• Primary Examiner(s): ULLAH, AKM E
• Application Number:
  US08/303,899
• Time in Patent Office: 697 Days
• Field of Search: 385/4-8, 385/11-14, 385/16-23, 385/147, 385/33, 385/116, 385/1-3, 385/10
• US Class Current: 385/4
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/3558 Poled materials, e.g. with periodic poling; Fabrication of domain inverted structures, e.g. for quasi-phase-matching [QPM]
• CPC Class Codes: G02F 1/377 in an optical waveguide structure
• CPC Class Codes: G02F 2201/30 grating
• CPC Class Codes: G02F 2201/305 diffraction grating
• CPC Class Codes: G02F 2201/307 Reflective grating, i.e. Bragg grating
• CPC Class Codes: G09F 9/305 being the ends of optical fibres G09F9/302 takes precedence
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A flat panel display is based on a new switching technology for routing laser light among a set of optical waveguides and coupling that light toward the viewer. The switching technology is based on poled electro-optical structures. The display technology is versatile enough to cover application areas spanning the range from miniature high resolution computer displays to large screen displays for high definition television formats. The invention combines the high brightness and power efficiency inherent in visible semiconductor diode laser sources with a new waveguide electro-optical switching technology to form a dense two-dimensional addressable array of high brightness light emissive pixels.

Claims

1. An optical beam directing element comprising:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

a pixel waveguide segment traversing said solid material along a plane of said solid material;

a plurality of output waveguide segments traversing said solid material along said plane, at least one of said output waveguide segments being transverse to said pixel waveguide segment in a first intersection region;

an active optical energy redirector being disposed adjacent said first intersection region, said active optical energy redirector to reflect optical energy from said pixel waveguide segment into said output waveguide segments upon selective application of an electrical field from said first electrode; and

optical reflector means disposed at selected locations on said plane in line with said output waveguide segments for projecting optical energy out of said plane.

2. The element according to claim 1 wherein said optical energy redirector comprises a switchable total internal reflector.

3. The element according to claim 1 wherein said optical energy redirector comprises a switchable grating reflector.

4. The element according to claim 1 wherein said optical energy redirector comprises a waveguide tap.

5. An optical beam routing structure forming an array employing at least one of said elements according to claim 1 to provide at least one second intersection region, further including:

a distribution waveguide abutting said pixel waveguide segment of at least one of said elements at said second intersection region, each said second intersection region having an active optical energy router disposed at said second intersection region to reroute optical energy into said pixel waveguide segment.

6. The beam routing structure according to claim 5 further including a fixed mirror disposed between said optical energy router and said optical redirector for directing optical energy within said plane.

7. The element according to claim 1, wherein said optical reflector means comprises:

an optical energy reflection boundary in said solid material, said reflection boundary having an index of refraction discontinuity across a surface transverse of an optical energy path and disposed at an angle to incident optical energy.

8. The element according to claim 1, wherein said optical reflector means comprises:

an index of refraction-implemented grating structure in said solid material, said grating structure formed by an index of refraction discontinuity pattern transverse to a propagation axis of and in the plane of incident optical energy.

9. The element according to claim 1, wherein at least one of said optical reflector means comprises:

phosphor target means disposed at a pixel location on said plane in line with said output waveguide segments.

10. The element according to claim 1 including an electrode associated with said optical energy redirector, said electrode being disposed at said first intersection region for controlling paths of optical energy.

11. The element according to claim 5 further including a plurality of electrodes disposed in a row and column pattern associated with a plurality of said first and said second intersection regions, with electrodes of a common column being connected to a common electrical conductor coupled to a field creating means.

12. The element according to claim 5 further including an optical frequency source means including an optical exciter coupled to said distribution waveguide.

13. The element according to claim 12 further including a frequency doubler means coupled to be excited by said optical exciter.

14. The element according to claim 13 wherein said frequency doubler means is a periodically poled structure in said solid material and wherein said solid material is a nonlinear optical periodically polable material.

15. The element according to claim 12 further including an optical beam modulator disposed at an output of said optical exciter.

16. The element according to claim 15 wherein said optical modulator is integrated into said solid material.

17. The element according to claim 12, including a plurality of distribution waveguides, wherein said optical exciter is an plurality of solid state lasers.

18. The element according to claim 12, including a plurality of distribution waveguides, wherein said optical exciter is an array of solid state lasers integrated on a single substrate.

19. The element according to claim 12 wherein said solid state lasers are aligned to direct energy transverse of said solid material plane, said plane containing mirrors for directing injected radiation into said distribution waveguides.

20. The element according to claim 19 wherein said solid state lasers are coupled in an alternating arrangement to said distribution waveguides.

21. The element according to claim 5 further including an optical frequency source means comprising a plurality of laser exciters each for generating a beam of a different optical frequency, a beam combiner coupled to each of said laser exciters for combining said different optical frequency beams, said beam combiner being output coupled to said distribution waveguide.

22. In the element according to claim 5, further including a waveguide cross structure with asymmetric loss for multiple distribution waveguide segments in parallel in said second intersection region, wherein at least one of said distribution waveguide segments has a first index of refraction distribution in a crossing region;

and wherein

said pixel waveguide segment traverses said at least one distribution waveguide segment, a second index of refraction distribution adjacent said crossing region with said distribution waveguide segment being significantly less than said first index of refraction distribution.

23. In the element according to claim 1, further including:

a waveguide cross structure with asymmetric loss for multiple pixel waveguide segments in parallel in said first intersection region, wherein at least one of said pixel waveguide segments has a first index of refraction distribution in a crossing region; and

wherein

at least one of said output waveguide segments traverses said at least one pixel waveguide segment, a second index of refraction distribution adjacent said crossing region with said pixel waveguide segment being significantly less than said first index of refraction distribution.

24. In the element according to claim 1, further including:

means disposed adjacent said optical reflector means for shielding out spurious optical radiation around said optical reflectors to prevent spurious optical radiation from projection along a viewing axis.

25. In the element according to claim 24, wherein said shielding means comprises a reflector disposed to direct spurious optical radiation away from said viewing axis.

26. In the element according to claim 24, wherein said shielding means comprises an optical energy absorber disposed to intercept spurious optical radiation.

27. In the element according to claim 1, further including:

means disposed along a surface of said solid material transverse to a viewing axis for absorbing spurious optical radiation not directed out of said solid material by said optical reflectors.

28. In the element according to claim 1, further including:

means disposed along a surface of said solid material transverse to a viewing axis for masking spurious optical radiation not directed out of said solid material by said optical reflectors.

29. An optical beam routing structure comprising:

a solid material for conveying optical energy;

a distribution waveguide segment traversing said solid material along a plane of said solid material;

at least one pixel waveguide segment traversing said solid material along a plane of said solid material and each abutting said distribution waveguide segment at an intersection region;

at least one passive optical energy router being disposed at said intersection region, said passive optical energy router to reflect a portion of said optical energy from said distribution waveguide segment into said pixel waveguide segment; and

an optical modulator for each said at least one pixel waveguide segment for individually modulating said portion of said optical energy.

30. The optical beam routing structure according to claim 29, further comprising:

an output waveguide segment coupled to receive optical energy directed from said at least one pixel waveguide segment; and

optical reflector means disposed at selected locations on said plane in line with said output waveguide segment for projecting optical energy out of said plane.

31. The structure according to claim 29 wherein a plurality of said passive optical routers are disposed along said distribution waveguide segment, each one of said passive optical routers passing a selective amount of optical energy and reflecting a complementary selective amount of optical energy, said selective amounts being established according to a desired distribution pattern.

32. A display device comprising:

a solid material for conveying optical energy;

at least one pixel waveguide segment traversing said solid material along a plane of said solid material;

a plurality of output waveguide segments traversing said solid material along said plane, said output waveguide segments abutting said at least one pixel waveguide segment at a plurality of intersections and coupled to receive optical energy from said at least one pixel waveguide segment;

optical reflector means disposed at selected locations on said plane in line with said output waveguide segments.

33. The device according to claim 32 further including:

a distribution waveguide abutting said at least one pixel waveguide segment at selected intersections, each of said intersections having an active optical energy router disposed at said intersection to reroute optical energy into said at least one pixel waveguide segment.

34. The device according to claim 33 including a plurality of electrodes, selected ones of said electrodes being disposed at said intersections for controlling paths of optical energy.

35. The device according to claim 32 further including:

a first distribution waveguide abutting a first set of said pixel waveguide segments at selected first intersections, each one of said first intersections having an active optical energy router disposed at said selected first intersection to reroute optical energy into one of said first set of said pixel waveguide segments;

a second distribution waveguide abutting a second set of said pixel waveguide segments at selected second intersections, each one of said second intersections having an active optical energy router disposed at said selected second intersection to reroute optical energy into one of said second set of said pixel waveguide segments.

36. The device according to claim 35 wherein said first waveguide segments are interleaved with said second waveguide segments;

and wherein

said optical reflector means are disposed in a two-dimensional array corresponding to picture elements of a display.

37. The device according to claim 35 wherein

a first set of said optical reflector means associated with said first distribution waveguide are disposed in a row and column arrangement in a first tile of the display;

and

a second set of said optical reflector means associated with said second distribution waveguide are disposed in a row and column arrangement in a second tile of the display.

38. The device according to claim 32, wherein said optical reflector means comprises:

an optical energy reflection boundary in said solid material, said reflection boundary having an index of refraction discontinuity across a surface transverse of an optical energy path and disposed at an angle to incident optical energy.

39. A display device comprising:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

at least one pixel waveguide segment traversing said solid material along a plane of said solid material;

a plurality of output waveguide segments traversing said solid material along said plane, said output waveguide segments abutting said pixel waveguide segment at a plurality of intersections;

a plurality of electrically-controlled optical redirectors, each optical redirector being disposed transverse of one of said intersections, said optical redirectors being capable of reflecting optical energy from said pixel waveguide segment into said output waveguide segments; and

phosphor target means disposed at selected pixel locations on said plane in line with said output waveguide segments for reradiating optical energy out of said plane in response to optical energy excitation.

40. The display device according to claim 39 further comprising:

an optical reflector means disposed at each pixel location on said plane in line with selected output waveguide segments for projecting optical energy out of said plane.

41. A display device including:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

an optical frequency source means including an optical exciter of a first frequency and a frequency doubler means coupled to be excited by said optical exciter;

at least one pixel waveguide segment traversing said solid material along a plane of said solid dielectric material;

a plurality of output waveguide segments traversing said solid material along said plane, said output waveguide segments abutting said pixel waveguide segment at a plurality of intersections; and

a plurality of electrically-controlled optical redirectors, each optical redirector being disposed transverse of one of said intersections, said optical redirectors to reflect optical energy from said pixel waveguide segment into said output waveguide segments.

42. The display device according to claim 41 further comprising:

phosphor target means disposed at selected pixel locations on said plane in line with said output waveguide segments for reradiating optical energy out of said plane in response to optical energy excitation, wherein one optical redirector is provided for each phosphor target means.

43. The display according to claim 41 further comprising:

an optical reflector means disposed at each pixel location on said plane in line with selected output waveguide segments for projecting optical energy out of said plane adjacent said phosphor target means.

44. The device according to claim 41 wherein said frequency doubler means is a periodic poled structure in said solid material.

45. A device for distributing optical energy within a volume comprising:

optical energy path means for transporting optical energy;

a plurality of optical coupling regions for said optical energy path means arranged in a pattern in said volume; and

energy field controllable optical coupling elements coupled to said optical energy path means at said optical coupling regions for controllably distributing said optical energy in said volume.

46. A method for distributing optical energy within a volume comprising:

transporting optical energy along a plurality of optical energy paths within said volume; and

controllably distributing said optical energy in said volume upon selective application of energy fields at a plurality of optical coupling regions of said optical energy paths.

47. The method according to claim 46 wherein said distributing step comprises switching energy fields between a first state and a second state, wherein in said first state, substantially all optical energy at a selected optical coupling region is directed in a first optical energy path and in said second state, substantially all optical energy at said selected optical coupling region is directed in a second optical energy path.

48. The method according to claim 47 further including the step of modulating said optical energy at an input to said optical energy paths.

49. The method according to claim 47 further including the step of modulating said optical energy at a plurality of parallel locations between an input to said optical energy paths and a plurality of outputs from said optical energy paths.

50. An optical beam directing element comprising:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

a pixel waveguide segment traversing said solid material along a plane of said solid material;

a plurality of output optical axes traversing said solid material along said plane, at least one of said output optical axes being transverse to said pixel waveguide segment in a first intersection region;

an active optical energy redirector being disposed adjacent said first intersection region, said active optical energy redirector to reflect optical energy from said pixel waveguide segment into said output optical axes upon selective application of an electrical field from said first electrode; and

optical reflector means disposed at selected locations on said plane in line with said output optical axes for projecting optical energy out of said plane.

51. A display device comprising:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

at least one pixel waveguide segment traversing said solid material along a plane of said solid material;

a plurality of output optical axes traversing said solid material along said plane, said output optical axes abutting said pixel waveguide segment at a plurality of intersections;

a plurality of electrically-controlled optical redirectors, each optical redirector being disposed transverse of one of said intersections, said optical redirectors being capable of reflecting optical energy from said pixel waveguide segment into said output optical axes; and

phosphor target means disposed at selected pixel locations on said plane in line with said output optical axes for reradiating optical energy out of said plane in response to optical energy excitation.

52. A display device including:

a solid material for conveying optical energy;

at least a first electrically-conductive material forming a first electrode, said first electrode confronting said solid material;

an optical frequency source means including an optical exciter of a first frequency and a frequency doubler means coupled to be excited by said optical exciter;

at least one pixel waveguide segment traversing said solid material along a plane of said solid dielectric material;

a plurality of output optical axes traversing said solid material along said plane, said output optical axes abutting said pixel waveguide segment at a plurality of intersections; and

a plurality of electrically-controlled optical redirectors, each optical redirector being disposed transverse of one of said intersections, said optical redirectors to reflect optical energy from said pixel waveguide segment into said output optical axes.