Methods and apparatus for actuating displays

• US 20070223080A1
• Filed: 01/19/2007
• Published: 09/27/2007
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger, Payne, Richard, Gandhi, Jignesh, Fijol, John, Steyn, Jasper, Hagood, Nesbitt
• Granted Patent: US 7,502,159 B2
• Time in Patent Office: Days
• US Class Current: 359/298
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38

Abstract

This invention relates to display apparatuses having an array of light modulators and a plurality of apertures formed in a layer of material. Each light modulator corresponds to one or more apertures and has a portion which may overlap a corresponding aperture, where the size of the overlap is proportional to a distance between the array and the layer of material.

Claims

1. A display apparatus comprising:

a plurality of apertures formed in a layer of material, wherein each aperture has at least one edge,

an array of shutter-based MEMS light modulators positioned between the layer of material and an intended viewer of the display apparatus, each light modulator including a shutter having a light obstructing portion for selectively obstructing passage of light through a corresponding one or more apertures, wherein

the shutter is shaped such that in a closed position, the light obstruction portion of the shutter overlaps the at least one edge of its corresponding one or more apertures,

the array is separated from the layer of material by a gap, and

the overlap is proportional to, and greater than or equal to the size of the gap.

2. The display apparatus of claim 1, wherein the overlap is greater than or equal to about 1 micron.

3. The display apparatus of claim 1, wherein the overlap is between about 1 micron and about 10 microns.

4. The display apparatus of claim 1, wherein the overlap is greater than about 10 microns.

5. The display apparatus of claim 1, wherein the shutter comprises one or more shutter apertures for allowing light to pass through the shutter, and wherein each shutter aperture corresponds to one of the one or more apertures that correspond to the shutter.

6. The display apparatus of claim 1, wherein the layer of materials is substantially reflective.

7. The display apparatus of claim 6, wherein the layer of material comprises a metal.

8. The display apparatus of claim 6, wherein the layer of material comprises a dielectric mirror.

9. The display apparatus of claim 6, comprising a light guide, wherein the layer of material reflects light escaping a backlight back towards the light guide.

10. The display apparatus of claim 6, comprising a light-absorbing material deposited on a side of the layer of material facing the array.

11. The display apparatus of claim 10, comprising a second reflective layer positioned on a rear side of the backlight.

12. The display apparatus of claim 1, wherein the array is formed on the layer of material.

13. The display apparatus of claim 12, wherein the layer of material is deposited on a light guide.

14. The display apparatus of claim 1, wherein the array is formed on a first substrate, and the layer of material is deposited on a second substrate other than the first substrate.

15. The display apparatus of claim 14, wherein the array is formed on a side of the first substrate that faces away from the viewer.

16. The display apparatus of claim 14, comprising a light guide, wherein the second substrate is positioned between the first substrate and the light guide.

17. The display apparatus of claim 1, comprising a spacer disposed between the layer of material and the array to keep the shutters in the light modulators about a predetermined distance from the layer of material

18. The display apparatus of claim 1, comprising a liquid located at least between the light modulators and the layer of material.

19. The display apparatus of claim 18, wherein the liquid is a lubricant.

20. The display apparatus of claim 18, wherein the liquid has a refractive index greater than a refractive index of a substrate on which the layer of material is formed.

21. The display apparatus of claim 18, comprising a light guide, wherein the liquid has a refractive index greater than a refractive index of the light guide.

22. The display apparatus of claim 14, comprising a light guide and a liquid having a refractive index greater than a refractive index of the second substrate, wherein the second substrate is positioned between the first substrate and the light guide, and the liquid is located at least between the second substrate and the light modulators.

23. The display apparatus of claim 1, wherein a side of the shutter facing the layer of material is coated with a reflective material.

24. The display apparatus of claim 1, wherein a side of the shutter facing the layer of material is coated with a light-absorbing material.

25. The display apparatus of claim 1, wherein a side of the shutter facing away from the layer of material is coated with a light-absorbing material.

26. A display apparatus comprising:

an array of electrowetting-based light modulators for transmissively displaying an image; and

a reflective aperture layer positioned adjacent the array for reflecting light not passing through apertures in the reflective aperture layer away from the array, wherein the image is formed from light that passes through apertures in the reflective aperture layer and that is modulated by the array.

27. The display apparatus of claim 26, comprising a backlight positioned on a side of the reflective aperture layer opposite the array.

28. The display apparatus of claim 26, comprising a second reflective layer positioned on a side of the reflective aperture layer opposite the array to reflect light towards the reflective aperture layer.

29. The display apparatus of claim 26, comprising a layer of low-refractive index material coupled to the light guide between the backlight and the reflective aperture layer.

30. The display apparatus of claim 26, wherein the array of electrowetting-based light modulators comprises a first electrowetting-controlled color modulation layer and a electrowetting-controlled black layer.

31. The display apparatus of claim 30, wherein:

the first electrowetting-controlled color modulation layer comprises a plurality of electrowetting-controlled color modulation cells each having at least one edge,

the electrowetting-controlled black layer includes a plurality of electrowetting-controlled light-absorbing cells corresponding to one or more of the color modulation cells, each having at least one edge, and

wherein the at least one edge of each light-absorbing cell overlaps the at least one edge of its corresponding one or more color modulation cells.

32. The display apparatus of claim 30, wherein the first electrowetting-controlled color modulation layer comprises groups of electrowetting-controlled color modulation cells, wherein each cell in a given group modulates a different color of light.

33. The display apparatus of claim 30, comprising second and third electrowetting-controlled color modulation layers, wherein each of the first, second, and third electrowetting-controlled color modulation layers modulates a different color of light.

34. The display apparatus of claim 27, comprising a light source for emitting light into the backlight.

35. The display apparatus of claim 34, wherein the light source emits white light.

36. The display apparatus of claim 34, wherein the light source sequentially emits light of at least three different colors.

37. The display apparatus of claim 36, wherein the light source comprises at least three light sources, each corresponding to one of the three different colors.

38. The display apparatus of claim 26, wherein the reflective aperture layer comprises a metal.

39. The display apparatus of claim 26, wherein the reflective aperture layer comprises a dielectric mirror.

40. The display apparatus of claim 26, wherein the array of electrowetting-based light modulators comprises a plurality of electrowetting-based light modulation cells, wherein each of the cells corresponds to an aperture in the reflective aperture layer.

41. The display apparatus of claim 40, wherein each of the apertures has at least one edge, each cell includes a layer of light modulating fluid, and when in a non-actuated state, the light modulating fluid of a cell overlaps the at least one edge of its corresponding aperture.

42. The display apparatus of claim 26, wherein the electrowetting-based light modulators comprise an electrode layer.

43. The display apparatus of claim 42, wherein the electrode layer is disposed between the reflective aperture layer and a light modulating fluid.

44. The display apparatus of claim 42, wherein the reflective aperture layer is disposed on a first substrate, and the electrode layer is disposed on a second substrate that is separate from the first substrate.

45. The display apparatus of claim 42, wherein a light modulating fluid is disposed between the reflective aperture layer and the electrode layer.