METHODS FOR MANUFACTURING COLD SEAL FLUID-FILLED DISPLAY APPARATUS

• US 20110157679A1
• Filed: 02/01/2011
• Published: 06/30/2011
• Est. Priority Date: 08/04/2008
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Wu, Joyce H., Gandhi, Jignesh, Steyn, Jasper Lodewyk, Fike, Eugene E. III
• Granted Patent: US 8,520,285 B2
• Time in Patent Office: Days
• US Class Current: 359/290
• CPC Class Codes: B32B 2309/027 Ambient temperature
• CPC Class Codes: B32B 2309/105 Thickness
• CPC Class Codes: B32B 2457/20 Displays, e.g. liquid crystal displays, plasma displays
• CPC Class Codes: B32B 37/003 to avoid air inclusion
• CPC Class Codes: B32B 37/1018 using only vacuum
• CPC Class Codes: G02B 26/005 based on electrowetting
• 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
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: H01J 9/26 Sealing together parts of vessels

Abstract

This methods and devices described herein relate to displays and methods of manufacturing cold seal fluid-filled displays, including MEMS. The fluid substantially surrounds the moving components of the MEMS display to reduce the effects of stiction and to improve the optical and electromechanical performance of the display. The invention relates to a method for sealing a MEMS display at a lower temperature such that a vapor bubble does not formforms only at temperatures about 15° C. to about 20° C. below the seal temperature. In some embodiments, the MEMS display apparatus includes a first substrate, a second substrate separated from the first substrate by a gap and supporting an array of light modulators, a fluid substantially filling the gap, a plurality of spacers within the gap, and a sealing material joining the first substrate to the second substrate.

Claims

1. A method for manufacturing a display assembly including a first transparent substrate and a second transparent substrate comprising:

providing at least a portion of an array of light modulators on the second transparent substrate;

providing a plurality of spacers connected to the first and second substrates to establish a gap between the two substrates;

providing an adhesive edge seal for bonding the perimeter of the first and second substrates;

filling the display assembly with a fluid at a first temperature;

cooling the display assembly to a second temperature substantially below the first temperature;

compressing the display assembly thereby pushing the first and second substrates at least partially together; and

curing a seal material to seal the fluid between the first and second substrates.

2. The method of claim 1, wherein the compressing step is performed at the second temperature.

3. The method of claim 1, wherein the plurality of spacers maintain at least a first gap between the two substrates.

4. The method of claim 1, wherein the adhesive edge seal maintains the edges of the first and second substrates separated by a second gap.

5. The method of claim 1, wherein the adhesive edge seal includes at least one edge spacer.

6. The method of claim 1, further comprising applying the seal material to a fill hole located along an edge of the display assembly after the display assembly is filled and before the display assembly is returned to room temperature.

7. The method of claim 6, wherein the fill hole comprises an opening in the adhesive edge seal.

8. The method of claim 1, wherein the first temperature is substantially room temperature.

9. The method of claim 1, wherein the first temperature is between about 18°

C. and about 30°

C.

10. The method of claim 1, wherein the second temperature is below about 0°

C.

11. The method of claim 1, wherein the curing the seal material occurs at a temperature below about 0°

C.

12. The method of claim 1, wherein the second temperature is between about −

10°

C. and −

25°

C.

13. The method of claim 1, wherein the fluid comprises a hydrofluoroether liquid.

14. The method of claim 1, wherein the fluid comprises a liquid blend of at least one perfluorocarbon and at least one hydrofluoroether.

15. The method of claim 1, wherein the light modulators are MEMS light modulators.

16. The method of claim 1, wherein filling the display via the fill hole is performed such that the fluid substantially surrounds the movable portions of the light modulators at the first temperature.

17. The method of claim 1, further comprising providing at least one additional array of MEMS light modulators on the first transparent substrate.

18. The method of claim 1, further comprising fabricating a plurality of spacers on at least one of the first and second transparent substrates to maintain a gap between the two substrates.

19. The method of claim 1, wherein the plurality of spacers has an elastic property that allows for the compressing at the second temperature.

20. The method of claim 1, wherein the plurality of spacers maintain at least a first gap between the two substrates, wherein the adhesive edge seal maintains the edges of the first and second substrates separated by a second gap, and wherein the height of the second gap is greater than the height of the first gap

21. The method of claim 20, wherein the height of the second gap is larger than the height of the first gap by between about 0.5 microns and about 4 microns.

22. The method of claim 20, wherein the height of the second gap is between about 8 microns and about 14 microns.

23. A method for manufacturing a display assembly including a first transparent substrate and a second transparent substrate comprising:

providing at least a portion of an array of light modulators on the second transparent substrate;

providing a plurality of spacers connected to the first and second substrates to establish a gap between the two substrates;

providing an adhesive edge seal for bonding the perimeter of the first and second substrates;

compressing the display assembly thereby pushing the first and second substrates at least partially together, wherein the compressing occurs at a temperature substantially below room temperature; and

curing a seal material to seal a fluid between the first and second substrates.

24. The method of claim 23, wherein room temperature is between about 18°

C. and about 30°

C.

25. The method of claim 23, wherein substantially below room temperature is below about 0°

C.

26. The method of claim 23, wherein substantially below room temperature is between about −

10°

C. and about −

25°

C.

27. The method of claim 23, wherein the curing of the seal material at least partially occurs at a temperature substantially below room temperature.

28. The method of claim 23, wherein the plurality of spacers has an elastic property that allows for the compressing at the second temperature.

29. The method of claim 23, wherein the plurality of spacers maintain at least a first gap between the two substrates, wherein the adhesive edge seal maintains the edges of the first and second substrates separated by a second gap, and wherein the height of the second gap is greater than the height of the first gap

30. The method of claim 29, wherein the height of the second gap is larger than the height of the first gap by between about 0.5 microns and about 4 microns.

31. The method of claim 29, wherein the height of the second gap is between about 8 microns and about 14 microns.

32. A display apparatus comprising;

a first substrate;

a second substrate including at least a portion of an array of light modulators and separated from the first substrate by at least a first gap;

a plurality of spacers connected to the first and second substrates to maintain the first gap;

an adhesive edge seal to maintain the edges of the display apparatus separated by at least a second gap, wherein the height of the second gap is greater than the height of the first gap;

a fluid contained within the first gap; and

a cured seal material to seal the fluid in the first gap.

33. The apparatus of claim 32, further comprising a fill hole, wherein the fill-hole comprises an opening in the adhesive edge seal.

34. The apparatus of claim 32, wherein the fluid comprises a hydrofluoroether liquid.

35. The apparatus of claim 32, wherein the fluid comprises a liquid blend of at least one perfluorocarbon and at least one hydrofluoroether.

36. The apparatus of claim 32, wherein the light modulators are MEMS light modulators.

37. The apparatus of claim 36, wherein the MEMS light modulators comprise shutter-based light modulators.

38. The apparatus of claim 36, wherein the MEMS light modulators comprise electrowetting light modulators.

39. The apparatus of claim 32, wherein the light modulators comprise liquid crystal modulators.

40. The apparatus of claim 32, wherein the first transparent substrate includes an additional portion of an array of light modulators.

41. The apparatus of claim 32, wherein the plurality of spacers are fabricated on one of the first and second transparent substrates.

42. The apparatus of claim 32, wherein the first substrate comprises one of a color filter array or an aperture layer formed thereon.

43. The apparatus of claim 32, wherein the height of the second gap is larger than the height of the first gap by between about 0.5 microns and 4 microns.

44. The apparatus of claim 32, wherein the height of the second gap is between about 8 microns and 14 microns.

45. The apparatus of claim 32, wherein the adhesive edge seal is an epoxy seal.

46. The apparatus of claim 45, wherein the epoxy seal is curable using an ultraviolet light source.

47. The apparatus of claim 45, wherein the adhesive edge seal includes at least one edge spacer.

48. The apparatus of claim 32, wherein the plurality of spacers has an elastic property that allows the spacers to maintain the first gap.