Method and system for maintaining partial vacuum in display device

• US 20060067647A1
• Filed: 07/15/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence
• Granted Patent: US 7,550,912 B2
• Time in Patent Office: Days
• US Class Current: 385/147
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

The time required for an interferometric modulator to switch from a state with a collapsed cavity to a state with an open cavity or vice versa, i.e., the switch time, is decreased by decreasing the viscosity of the gas filling the cavity. The viscosity is decreased by forming at least a partial vacuum in the cavity. The partial vacuum is formed, in turn, by forming a cavity in a housing holding the interferometric modulator. The vacuum can be generated by a vacuum pump. By decreasing the switch time, interferometric modulators in an array of interferometric modulators can be switched more quickly, thereby advantageously increasing the refresh rate for a display using the array.

Claims

1. A method of fabricating a display device, comprising:

providing a transparent substrate having an interferometric modulator formed thereon, wherein the interferometric modulator is configured to modulate light transmitted through the transparent substrate;

joining a backplate to the transparent substrate to form a package, wherein the package encapsulates the interferometric modulator; and

reducing gas pressure within the package.

2. The method of claim 1, wherein the gas pressure within the package is reduced to less than about 0.85 atmospheres.

3. The method of claim 2, wherein the gas pressure within the package is reduced to less than about 0.24 atmospheres.

4. The method of claim 1, wherein reducing the gas pressure comprises providing at least a partial vacuum around the package.

5. The method of claim 4, wherein providing at least a partial vacuum around the package comprises:

sealing the package within a housing; and

connecting a vacuum device to the housing, wherein the vacuum device is configured to generate at least a partial vacuum within a cavity between the housing and the package, and wherein the backplate comprises at least one gas passage in communication with the cavity.

6. The method of claim 1, wherein reducing the gas pressure decreases switch time of the interferometric modulator.

7. A display device formed by a method comprising:

providing a transparent substrate having an interferometric modulator formed thereon, wherein the interferometric modulator is configured to modulate light transmitted through the transparent substrate;

joining a backplate to the transparent substrate to form a package, wherein the package encapsulates the interferometric modulator; and

reducing gas pressure within the package.

8. The display device of claim 7, wherein the gas pressure within the package is reduced to less than about 0.85 atmospheres.

9. The display device of claim 7, wherein reducing the gas pressure comprises providing at least a partial vacuum around the package.

10. A microelectromechanical systems device, comprising:

a transparent substrate;

an interferometric modulator formed on the transparent substrate, wherein the interferometric modulator is configured to modulate light transmitted through the transparent substrate;

a backplate sealed to the transparent substrate to form a package having a first cavity with at least a partial vacuum.

11. The microelectromechanical systems device of claim 10, further comprising a vacuum housing configured to hold the package, wherein the housing is configured to be connected to a vacuum device.

12. The microelectromechanical systems device of claim 11, wherein the vacuum device is configured to generate at least a partial vacuum within a second cavity between the housing and the package.

13. The microelectromechanical systems device of claim 12, wherein the backplate comprises at least one gas passage in communication with the second cavity.

14. The microelectromechanical systems device of claim 13, wherein the gas passage comprises a cover configured to be in an open position when the vacuum device is on.

15. The microelectromechanical systems device of claim 14, wherein the cover is configured to open when at least a partial vacuum is generated within the second cavity.

16. The microelectromechanical systems device of claim 14, wherein the cover comprises a mechanical actuator.

17. The microelectromechanical systems device of claim 10, wherein the backplate is sealed to the transparent substrate with a hermetic seal.

18. The microelectromechanical systems device of claim 10, further comprising:

a display;

a processor that is in electrical communication with said display, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

19. The microelectromechanical systems device of claim 18, further comprising:

a first controller configured to send at least one signal to said display; and

a second controller configured to send at least a portion of said image data to said first controller.

20. The microelectromechanical systems device of claim 18, further comprising:

an image source module configured to send said image data to said processor.

21. The microelectromechanical systems device of claim 20, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

22. The microelectromechanical systems device of claim 18, further comprising:

an input device configured to receive input data and to communicate said input data to said processor.

23. A method of fabricating a display device, comprising:

providing a panel comprising a substrate joined to a backplate, wherein the substrate has an interferometric modulator formed thereon and encapsulated within the panel, wherein the interferometric modulator is configured to modulate light transmitted through the substrate; and

reducing gas pressure within the panel.

24. The method of claim 23, wherein the gas pressure within the panel is reduced to less than about 0.85 atmospheres.

25. The method of claim 24, wherein the gas pressure within the panel is reduced to less than about 0.24 atmospheres.

26. The method of claim 23, wherein reducing the gas pressure comprises providing at least a partial vacuum within the panel.

27. The method of claim 26, wherein providing at least a partial vacuum within the panel comprises operating a vacuum device connected to the panel.

28. The method of claim 26, wherein providing at least a partial vacuum within the panel comprises:

sealing the panel within a housing; and

connecting a vacuum device to the housing, wherein the vacuum device is configured to generate at least a partial vacuum within a cavity between the housing and the package, and wherein the backplate comprises at least one gas passage in communication with the cavity.

29. A display device, comprising:

a substrate configured to transmit light therethrough;

a modulating means for modulating light transmitted through the substrate, wherein the modulating means is formed on the substrate and has a first cavity therein, wherein the cavity has a gas pressure less than atmospheric pressure;

a backplate sealed to the substrate to form a package.

30. The display device of claim 29, further comprising a vacuum housing configured to hold the package, wherein the housing is configured to be connected to a vacuum device.

31. The display device of claim 30, wherein the vacuum device is configured to generate at least a partial vacuum within a second cavity between the housing and the package to lower gas pressure within the first cavity in the modulating means.

32. The display device of claim 31, wherein the backplate comprises at least one gas passage in communication with the second cavity.

33. The display device of claim 32, wherein the gas passage comprises a cover configured to be in an open position while the vacuum device is operating.

34. The display device of claim 33, wherein the cover is configured to open when at least a partial vacuum is generated within the second cavity.

35. The display device of claim 33, wherein the cover comprises a mechanical actuator.

36. The display device of claim 29, wherein the backplate is sealed to the substrate with a hermetic seal.