Methods and devices for inhibiting tilting of a mirror in an interferometric modulator

• US 20060077527A1
• Filed: 06/16/2005
• Published: 04/13/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Cummings, William J.
• Granted Patent: US 7,130,104 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

Interferometric modulators having a separable modulator architecture are disclosed having a reflective layer suspended from a flexible layer over a cavity. The interferometric modulators have one or more anti-tilt members that inhibit undesirable movement of the reflective layer, such as curling and/or tilting. The stabilization of the reflective layer by the anti-tilt members can improve the quality of the optical output of the interferometric modulators, as well as displays comprising such interferometric modulators.

Claims

1. An interferometric modulator comprising:

a substrate;

an optical layer positioned over the substrate, the optical layer being at least partially transmissive to incident light;

a mirror positioned over the substrate and movable between a first position spaced from the optical layer by a first distance and a second position spaced from the optical layer by a second distance, the first distance being greater than the second distance, and the mirror having a surface away from the substrate; and

at least one stationary member contacting the surface of the mirror when the mirror is in the first position, wherein the at least one stationary member is configured to inhibit movement of at least a portion of the mirror when the mirror is in the first position.

2. The interferometric modulator of claim 1, wherein the mirror is substantially parallel to the optical layer when in the first position.

3. The interferometric modulator of claim 1, wherein the mirror is substantially planar when in the first position.

4. The interferometric modulator of claim 1, wherein the at least one member inhibits movement of at least a portion of the mirror in a direction generally perpendicular to the mirror when the mirror is in the first position.

5. The interferometric modulator of claim 4, wherein the at least one member inhibits movement of at least a portion of the mirror in a direction generally parallel to the mirror when the mirror is in the first position.

6. The interferometric modulator of claim 4, wherein the at least one member inhibits rotational movement of at least a portion of the mirror when the mirror is in the first position.

7. The interferometric modulator of claim 1, wherein the at least one member inhibits movement of at least a portion of the mirror in a direction generally parallel to the mirror when the mirror is in the second position.

8. The interferometric modulator of claim 7, wherein the at least one member inhibits rotational movement of at least a portion of the mirror when the mirror is in the second position.

9. The interferometric modulator of claim 1, wherein the at least one member inhibits movement of at least a portion of the mirror in a direction generally parallel to the mirror when the mirror occupies a position between the first and second positions.

10. The interferometric modulator of claim 9, wherein the at least one member inhibits rotational movement of at least a portion of the mirror when the mirror occupies a position between the first and second positions.

11. The interferometric modulator of claim 4, wherein the at least one member comprises a single segment that is substantially curvilinear.

12. The interferometric modulator of claim 11, wherein an end portion of the at least one member contacts at least a portion of the mirror when the mirror is in the first position.

13. The interferometric modulator of claim 1, wherein the mirror further comprises at least one recess that contacts the at least one member when the mirror is in the first position.

14. The interferometric modulator of claim 1, wherein the mirror shields the at least one member from light incident to the interferometric modulator.

15. The interferometric modulator of claim 1, further comprising a mechanical layer attached to the mirror that suspends the mirror over the substrate, wherein the mechanical layer exerts a force on the mirror that facilitates contact between the at least one member and the surface of the mirror when the mirror is in the first position.

16. The interferometric modulator of claim 1, wherein the at least one member comprises a shaft segment substantially perpendicular to the mirror and a head segment connected to the shaft segment.

17. The interferometric modulator of claim 16, wherein the head segment is substantially perpendicular to the shaft segment.

18. The interferometric modulator of claim 16, wherein the head segment is at an acute angle to the shaft segment.

19. The interferometric modulator of claim 16, wherein the shaft segment inhibits movement of at least a portion of the mirror in a direction generally parallel to the mirror when the mirror is in the first position, and the head segment inhibits movement of at least a portion of the mirror in a direction generally perpendicular to the mirror when the mirror is in the first position.

20. The interferometric modulator of claim 16, wherein the head segment contacts at least a portion of the surface of the mirror when the mirror is in the first position.

21. The interferometric modulator of claim 16, wherein at least a portion of the head segment has a width larger than a width of the shaft segment.

22. The interferometric modulator of claim 16, wherein the shape of the head segment is selected from the group comprising substantially rectangular, substantially conical, barbed, substantially spherical, oblong, and substantially hook-shaped.

23. The interferometric modulator of claim 16, wherein the shape of the shaft is selected from the group consisting of:

substantially conical, substantially rectangular, substantially triangular, and substantially round.

24. The interferometric modulator of claim 16, wherein the head segment further comprises a convex portion that contacts at least a portion of the mirror when the mirror is in the first position.

25. The interferometric modulator of claim 24, wherein the mirror further comprises a recessed portion that contacts the convex portion of the head segment when the mirror is in the first position.

26. The interferometric modulator of claim 16, wherein the at least one member further comprises a contact region connected to the head segment, wherein said contact region contacts at least a portion of the surface of the mirror when the mirror is in the first position.

27. A member for reducing the movement of a mirror in an interferometric modulator, the member comprising:

a shaft segment configured to inhibit lateral movement of at least a portion of a mirror in an interferometric modulator in a direction substantially parallel to the mirror; and

at least one head segment configured to inhibit movement of at least a portion of a mirror in an interferometric modulator in a direction generally perpendicular to the mirror.

28. The member of claim 27, wherein the member is configured to inhibit movement of at least a portion of a first mirror of a first interferometric modulator and to inhibit movement of at least a portion of a second mirror of a second interferometric modulator.

29. A visual display device comprising a plurality of interferometric modulators, each interferometric modulator comprising:

a substrate;

an optical layer positioned over the substrate, the optical layer being at least partially transmissive to incident light;

a mirror positioned over the substrate and movable between a first position spaced from the optical layer by a first distance and a second position spaced from the optical layer by a second distance, the first distance being greater than the second distance, and the mirror having a surface facing away from the substrate; and

at least one stationary member contacting the surface of the mirror when the mirror is in the first position, wherein the at least one stationary member is configured to inhibit movement of at least a portion of the mirror when the mirror is in the first position.

30. The visual display device of claim 29, 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.

31. The visual display device of claim 30, 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.

32. The visual display device of claim 30, further comprising an image source module configured to send said image data to said processor.

33. The visual display device of claim 32, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

34. The visual display device of claim 30, further comprising an input device configured to receive input data and to communicate said input data to said processor.

35. An interferometric modulator comprising:

a substrate;

an optical layer positioned over the substrate, the optical layer being at least partially transmissive to incident light;

a mirror positioned over the substrate and movable between a first position spaced from the optical layer by a first distance and a second position spaced from the optical layer by a second distance, the first distance being greater than the second distance, and the mirror having a surface facing away from the substrate; and

at least one stationary mirror-stabilizing means configured to maintain the mirror in a desired orientation when the mirror is in the first position, said mirror-stabilizing means contacting the surface of the mirror when the mirror is in the first position.

36. The interferometric modulator of claim 35, wherein the mirror-stabilizing means is configured to maintain the mirror in a substantially planar orientation when the mirror is in the first position.

37. The interferometric modulator of claim 35, wherein the mirror-stabilizing means is configured to maintain the mirror substantially parallel to the substrate when the mirror is in the first position.