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

• US 7,385,762 B2
• Filed: 10/30/2006
• Issued: 06/10/2008
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Cummings, William J.
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US11/589,582
• Publication Number:
  US 20070040777A1
• Time in Patent Office: 589 Days
• Field of Search: 359/578, 359584-589, 359/223, 359/224, 359290-292, 359/295, 359/298, 359315-318
• US Class Current: 359/578
• 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. A device comprising:

an array of at least two 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, wherein light reflected by the interferometric modulator is interferometrically modulated; 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;

wherein the stationary members of the at least two interferometric modulators contact the surface of each respective mirror at a different first distance from the optical layer when the mirrors are in the first position.

2. The device of claim 1, 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.

3. The device of claim 2, 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.

4. The device of claim 2, further comprising an image source module configured to send said image data to said processor.

5. The device of claim 4, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

6. The device of claim 2, further comprising an input device configured to receive input data and to communicate said input data to said processor.

7. The device of claim 1, wherein the at least one stationary member is located between the at least two interferometric modulators, and the stationary member comprises a shaft segment, a first head segment connected to the shaft segment and contacting the mirror of a first of the at least two interferometric modulators, and a second head segment connected to the shaft segment and contacting the mirror of a second of the at least two interferometric modulators.

8. The device of claim 7, wherein the at least one stationary member inhibits movement of at least a portion of both the mirrors of each of the first and second interferometric modulators in a direction generally perpendicular to the surfaces of the mirrors when the mirrors are in the first position.

9. The device of claim 7, wherein the at least one stationary member inhibits movement of at least a portion of both the mirrors of each of the first and second interferometric modulators in a direction generally parallel to the surfaces of the mirrors when the mirrors are in the first position.

10. The device of claim 7, wherein the at least one stationary member inhibits rotational movement of at least a portion of both the mirrors of the first and second interferometric modulators when the mirrors are in the first position.

11. The device of claim 1, further comprising a third interferometric modulator, wherein the first distance between the mirror and the optical layer when the mirror is in the first position is different for each of the three interferometric modulators.

12. The device of claim 11, wherein the three different first distances are dimensioned such that different colors of light are reflected by the three interferometric modulators when the mirrors are in the first position.

13. The device of claim 12, wherein the different colors comprise red, green and blue.

14. The device 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.

15. The device of claim 1, further comprising a mechanical layer having at least one portion that is attached to the mirror and a second portion that is attached to at least one of the stationary members.

16. An array of at least two interferometric modulators, each interferometric modulator comprising:

means for supporting at least a portion of the interferometric modulator;

means for transmitting light, the transmitting means positioned over the supporting means, the transmitting means at least partially transmissive to incident light;

means for reflecting light, the reflecting means positioned over the supporting means and movable between a first position spaced from the transmitting means by a first distance and a second position spaced from the transmitting means by a second distance, the first distance being greater than the second distance, and the reflecting means having a surface away from the supporting means, wherein light reflected by the interferometric modulator is interferometrically modulated; and

means for stabilizing the reflecting means, the stabilizing means contacting the surface of the reflecting means when the reflecting means is in the first position,

wherein the stabilizing means is configured to inhibit movement of at least a portion of the reflecting means when the reflecting means is in the first position;

wherein the stabilizing means of the at least two interferometric modulators contact the surface of each respective reflecting means at a different first distance from the transmitting means when the reflecting means are in the first position.

17. The array of interferometric modulators of claim 16, wherein the reflecting means is at an angle non-parallel to the supporting means in the first position.

18. The array of interferometric modulators of claim 16, wherein the supporting means comprises a substrate.

19. The array of interferometric modulators of claim 16, wherein the transmitting means comprises an optical layer.

20. The array of interferometric modulators of claim 16, wherein the reflecting means comprises a mirror.

21. The array of interferometric modulators of claim 16, wherein the stabilizing means comprises at least one stationary member.

22. 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 and a second position, wherein a portion of the mirror is spaced from the optical layer by a first distance in the first position, and the portion of the mirror is spaced from the optical layer by a second distance in the second position, the first distance being greater than the second distance, and the mirror having a surface away from the substrate, wherein light reflected by the interferometric modulator is interferometrically modulated; and

at least one stationary member contacting the surface of the mirror facing away from the substrate 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, and further wherein the mirror is positioned and an angle non-parallel to the substrate in the first position.

23. The interferometric modulator of claim 22, wherein the mirror comprises a second portion and the at least one stationary member contacts the second portion of the mirror when the mirror is in the first position.

24. The interferometric modulator of claim 23, wherein the second portion of the mirror is spaced from the optical layer by a smaller first distance in the first position than the first distance that first portion of the mirror is spaced form the optical layer in the first position.

25. The interferometric modulator of claim 22, 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.

26. The interferometric modulator of claim 22, further comprising a second stationary member contacting the surface of the mirror when the mirror is in the first position, wherein the second stationary member is configured to inhibit movement of at least a portion of the mirror when the mirror is in the first position, and further wherein the at least one stationary member and the second stationary member contact the mirror at different distances from the substrate.