Methods and apparatus for actuating displays

• US 7,898,714 B2
• Filed: 07/31/2008
• Issued: 03/01/2011
• Est. Priority Date: 02/23/2005
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger W., Hagood, Nesbitt W. IV
• Primary Examiner(s): Choi; William C
• Application Number:
  US12/221,193
• Publication Number:
  US 20090034052A1
• Time in Patent Office: 943 Days
• Field of Search: 359/228, 359/665, 359/886, 359/291, 359/297, 359/666
• US Class Current: 359/228
• 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 for transmissively displaying an image and a reflective aperture layer defining a plurality of apertures, for reflecting light not passing through apertures in the reflective aperture layer away from the array. The reflective aperture layer is formed on a first substrate and positioned adjacent the array. The image is formed by modulating light passing through the apertures in the reflective aperture layer. A light guide, separated from the first substrate by a gap, may guide light towards the reflective aperture layer. A layer of low-refractive index material may be positioned on a side of the reflective aperture layer opposite the array.

Claims

1. A display apparatus comprising:

an array of electrowetting-based light modulators for transmissively displaying an image wherein the array of electrowetting-based light modulators comprises a first electrowetting-controlled color modulation layer and an electrowetting-controlled black layer;

a reflective aperture layer defining a plurality of apertures, for reflecting light not passing through apertures in the reflective aperture layer away from the array, wherein the reflective aperture layer is formed on a first substrate and positioned adjacent the array, and the image is formed by modulating light passing through the apertures in the reflective aperture layer; and

a light guide, separated from the first substrate by a gap, for guiding light towards the reflective aperture layer.

2. The display apparatus of claim 1, 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.

3. The display apparatus of claim 1, comprising a fluid filling the gap.

4. The display apparatus of claim 3, wherein the fluid has a first refractive index and the light guide has a second refractive index, the first refractive index being less than the second refractive index.

5. The display apparatus of claim 3, wherein the fluid is air.

6. The display apparatus of claim 1, 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.

7. The display apparatus of claim 1, 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.

8. The display apparatus of claim 1, 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.

9. The display apparatus of claim 1, comprising a light source for emitting light into the light guide.

10. The display apparatus of claim 9, wherein the light source emits white light.

11. The display apparatus of claim 9, wherein the light source sequentially emits light of at least three different colors.

12. The display apparatus of claim 11, wherein the light source comprises at least three light sources, each corresponding to one of the three different colors.

13. The display apparatus of claim 1, wherein the reflective aperture layer comprises a metal.

14. The display apparatus of claim 1, wherein the reflective aperture layer comprises a dielectric mirror.

15. The display apparatus of claim 1, 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.

16. The display apparatus of claim 15, 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.

17. The display apparatus of claim 1, wherein the electrowetting-based light modulators comprise an electrode layer.

18. The display apparatus of claim 17, wherein the electrode layer is disposed between the reflective aperture layer and a light modulating fluid.

19. The display apparatus of claim 17, 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.

20. The display apparatus of claim 17, wherein a light modulating fluid is disposed between the reflective aperture layer and the electrode layer.

21. The display apparatus of claim 1, comprising

a layer of low-refractive index material positioned on a side of the reflective aperture layer opposite the array.

22. The display apparatus of claim 21, wherein the layer of low-refractive index material has a refractive index less than that of the light guide.

23. The display apparatus of claim 21, wherein the layer of low-refractive index material is interposed between the reflective aperture layer and the light guide.

24. The display apparatus of claim 21, 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.

25. The display apparatus of claim 21, wherein the layer of low-refractive index material is formed on the first substrate.

26. A display apparatus comprising:

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

a reflective aperture layer defining a plurality of apertures, for reflecting light not passing through apertures in the reflective aperture layer away from the array, wherein the reflective aperture layer is formed on a first substrate and positioned adjacent the array, and the image is formed by modulating light passing through the apertures in the reflective aperture layer;

a light guide, separated from the first substrate by a gap, for guiding light towards the reflective aperture layer; and

a light source for emitting light into the light guide, wherein the light source comprises at least three light sources, each corresponding to one of the three different colors.

27. 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.

28. The display apparatus of claim 26, comprising a fluid filling the gap.

29. The display apparatus of claim 28, wherein the fluid has a first refractive index and the light guide has a second refractive index, the first refractive index being less than the second refractive index.

30. The display apparatus of claim 28, wherein the fluid is air.

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

32. The display apparatus of claim 31, 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.

33. The display apparatus of claim 31, 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.

34. The display apparatus of claim 31, 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.

35. The display apparatus of claim 26, wherein the light source emits white light.

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

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

38. 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.

39. The display apparatus of claim 38, 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.

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

41. The display apparatus of claim 40, wherein the electrode layer is disposed between the reflective aperture layer and a light modulating fluid.

42. The display apparatus of claim 40, 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.

43. The display apparatus of claim 40, wherein a light modulating fluid is disposed between the reflective aperture layer and the electrode layer.

44. The display apparatus of claim 26, comprising a layer of low-refractive index material positioned on a side of the reflective aperture layer opposite the array.

45. The display apparatus of claim 44, 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.

46. The display apparatus of claim 45, wherein the layer of low-refractive index material is interposed between the reflective aperture layer and the light guide.

47. The display apparatus of claim 44, wherein the layer of low-refractive index material has a refractive index less than that of the light guide.

48. The display apparatus of claim 44, wherein the layer of low-refractive index material is formed on the first substrate.