Light concentrating reflective display methods and apparatus

• US 20060250676A1
• Filed: 02/23/2006
• Published: 11/09/2006
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Hagood, Nesbitt W. IV
• Granted Patent: US 7,616,368 B2
• Time in Patent Office: Days
• US Class Current: 359/296
• CPC Class Codes: G02B 17/002 Arrays of reflective systems
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

Improved apparatus and methods for displays are disclosed that utilize light concentration array between mechanical light modulators and the viewing surface of the display. The light concentration array includes an array of optical elements that concentrate light on respective ones of the light modulators to maximize the contrast ratio and off axis viewing of the display.

Claims

1. A display apparatus comprising:

an array of light modulators for selectively reflecting light towards a viewer to form an image;

an array of reflective light funnels disposed between the array of light modulators and the viewer, for concentrating light on respective ones of the light modulators in the array of light modulators.

2. The display apparatus of claim 1, wherein one of the reflective light funnels in the array of reflective light funnels comprises a first optical opening directed towards the viewer, a second, smaller optical opening directed towards a respective one of the light modulators, and a reflective wall connecting the first optical opening to the second optical opening.

3. The display apparatus of claim 2, wherein the reflective wall comprises a reflective material deposited on the interior of the reflective light funnel.

4. The display apparatus of claim 2, wherein the reflective wall comprises a substantially transparent interior coated by a reflective material.

5. The display apparatus of claim 2, wherein the wall is generally conical in shape.

6. The display apparatus of claim 2, wherein the wall has a hexagonal cross section.

7. The display apparatus of claim 2, wherein the wall has a rectangular cross section.

8. The display of the of claim 2, wherein the wall comprises a polygonal cross section.

9. The display apparatus of claim 1, wherein height of the reflective light funnel is smaller than the diameter of the first optical opening.

10. The display apparatus of claim 1, wherein the height of the reflective light funnel is greater than the diameter of the first optical opening.

11. The display apparatus of claim 1, wherein one of the light modulators in the array of light modulators comprises a MEMS-based light modulator.

12. The display apparatus of claim 11, wherein the one light modulator comprises a shutter.

13. The display apparatus of claim 12, wherein the shutter comprises a reflective material for reflecting light towards the viewer.

14. The display apparatus of claim 13, wherein the shutter selectively obstructs light from impinging on a light-absorbing material disposed behind the shutter in relation to the viewer.

15. The display apparatus of claim 12, wherein the shutter comprises a light-absorbing material.

16. The display apparatus of claim 15, wherein the shutter selectively obstructs light from impacting a reflective surface located behind the shutter in relation to the viewer.

17. The display apparatus of claim 11, wherein the one light modulator comprises two shutters.

18. The display apparatus of claim 17, wherein one of the two shutters is larger than the other of the two shutters.

19. The display apparatus of claim 17, wherein the two shutters selectively obstruct light from reflecting off a reflective surface towards the viewer.

20. The display apparatus of the claim 17, wherein the two shutters reflect light towards the viewer.

21. The display apparatus of claim 20, wherein the two shutters selectively allow light to impact a light absorbing surface located behind the two shutters in relation to the viewer.

22. The display apparatus of claim 1, comprising an array of color filters corresponding to respective ones of the light modulators.

23. The display apparatus of claim 17, wherein the array of color filters includes a plurality of red filters, green filters, and blue filters.

24. The display apparatus of claim 23, wherein the array of color filters includes a plurality of white filters.

25. A display apparatus comprising:

an array of MEMS-based light modulators for selectively modulating light to form an image; and

an array of reflective light funnels disposed between the array of MEMS-based light modulators and a viewer, for concentrating light on respective ones of the light modulators in the array of light modulators.

26. The display apparatus of claim 25, comprising a backlight.

27. The display apparatus of claim 26, wherein the MEMS-based light modulators selectively transmit light from the backlight towards the viewer and selectively reflect light originating from the direction of the viewer.

28. The display of claim 25, comprising a front light.

29. The display of claim 25, wherein the MEMS-based light modulators modulate light by reflecting light towards the viewer.

30. The display apparatus of claim 25, wherein one of the MEMS-based light modulators comprises a shutter.

31. The display apparatus of claim 30, wherein the shutter comprises a reflective material for reflecting light towards the viewer.

32. The display apparatus of claim 31, wherein the shutter selectively obstructs light from impacting a light-absorbing surface behind the shutter with respect to the viewer.

33. The display apparatus of claim 25, wherein the shutter comprises a light-absorbing material.

34. The display apparatus of claim 33, wherein the shutter selectively obstructs light from impacting a reflective surface behind the shutter with respect to the viewer.

35. The display apparatus of claim 30, wherein the one MEMS-based light modulator comprises a second shutter.

36. The display apparatus of claim 35, wherein the first shutter covers a larger area surface than the second shutter.

37. The display apparatus of claim 25, comprising an array of color filters corresponding to respective ones of the light modulators.

38. The display apparatus of claim 37, wherein the array of color filters includes a plurality of red filter, green filters, and blue filters.

39. A display apparatus comprising:

an array of MEMS-based light modulators for selectively modulating light to form an image; and

an array of reflective light funnels disposed between a backlight and the array of MEMS-based light modulators for increasing the fraction of light generated by the backlight that is modulated by the MEMS-based light modulators.

40. The display apparatus of claim 39, wherein the MEMS-based light modulators selectively transmit light generated in the backlight toward a viewer.

41. A method of manufacturing a display apparatus comprising:

forming an array of reflective light modulators;

forming an array of reflective light funnels by

forming an array of depressions in a sheet of a substantially transparent material, each depressions having a top, a bottom, and a wall;

depositing a reflective film on the walls of the depressions; and

forming optical openings at the bottom of the depressions such that the optical openings have a diameter which is smaller than the diameter of the top of the depression.

42. A method of manufacturing a display apparatus comprising:

forming an array of reflective light modulators;

forming an array of reflective light funnels by

providing a substantially transparent layer of material;

removing material from the substantially transparent layer of material, leaving a plurality of solid cones formed from the material, each cone having a tip;

depositing a reflective coating on a surface of the cones;

forming optical opening at the cone tips; and

depositing a back fill material on top of the reflective coating.