System and method for micro-electromechanical operation of an interferometric modulator

• US 7,567,373 B2
• Filed: 07/26/2005
• Issued: 07/28/2009
• Est. Priority Date: 07/29/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Gally, Brian J., Chui, Clarence, Cummings, William J., Tung, Ming-Hau
• Primary Examiner(s): Dang; Hung X.
• Assistant Examiner(s): TRA, TUYEN Q
• Application Number:
  US11/189,690
• Publication Number:
  US 20060024880A1
• Time in Patent Office: 1,463 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298, 359/220, 359/222, 359/223, 359/320, 359/322, 359/315, 359/318, 345/85, 348770-772
• US Class Current: 359/291
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/001 Structures having a reduced contact area, e.g. with bumps or with a textured surface
• 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

An interferometric modulator is formed by a stationary layer and a mirror facing the stationary layer. The mirror is movable between the undriven and driven positions. Landing pads, bumps or spring clips are formed on at least one of the stationary layer and the mirror. The landing pads, bumps or spring clips can prevent the stationary layer and the mirror from contacting each other when the mirror is in the driven position. The spring clips exert force on the mirror toward the undriven position when the mirror is in the driven position and in contact with the spring clips.

Claims

1. An interferometric modulator, comprising:

a first layer comprising a first reflective planar portion;

a second layer comprising a second reflective planar portion located substantially parallel to the first reflective planar portion, the second layer movable between a first position and a second position, the first position being a first distance from the first layer, the second position being a second distance from the first layer, the second distance being greater than the first distance; and

a member having a surface located between the first layer and the second layer, the member defining one or more gap regions between the first layer and the second layer when the second layer is in the first position, the surface comprising a dielectric material which contacts at least one of the first layer and the second layer when the second layer is in the first position.

2. The interferometric modulator of claim 1, wherein the first reflective planar portion is partially reflective and partially transmissive to light in a predetermined wavelength range.

3. The interferometric modulator of claim 1, wherein the second planar portion is substantially reflective to light in a predetermined wavelength range.

4. The interferometric modulator of claim 1, further comprising a third layer between the first layer and the second layer, the third layer substantially transparent to light in a predetermined wavelength range, wherein the third layer comprises a dielectric layer.

5. The interferometric modulator of claim 4, wherein the second layer in the one or more gap regions does not contact at least a portion of the third layer when the second layer is in the first position.

6. The interferometric modulator of claim 1, wherein the member is spaced from the second layer when the second layer is in the second position, and wherein the surface is contacted by the second layer when the second layer is in the first position.

7. A microelectromechanical device, comprising:

a first surface having a first surface area;

a second surface having a second surface area, the second surface being located substantially parallel to the first surface, the second surface movable between a first position and a second position, the first position being a first distance from the first surface, the second position being a second distance from the first surface, the second distance being greater than the first distance; and

a third surface located between the first surface and the second surface, the third surface defining one or more gap regions between the first surface and the second surface when the second surface is in the first position,

wherein the second surface in the one or more gap regions does not contact either the first surface or the third surface, and

wherein the third surface comprises a dielectric material, and

wherein the third surface provides a contact area which contacts at least one of the first surface and the second surface when the second surface is in the first position.

8. The microelectromechanical device of claim 7, wherein the third surface comprises a surface of a member that is positioned on a peripheral portion of at least one of the first surface and the second surface.

9. The microelectromechanical device of claim 8, wherein the third surface contacts the second surface when the second surface is in the first position.

10. The microelectromechanical device of claim 9, wherein the third surface comprises a material different from a material which comprises either the first or second surfaces.

11. The microelectromechanical device of claim 9, wherein the third surface comprises a material which also comprises either the first or second surfaces.

12. The microelectromechanical device of claim 8, wherein the third surface comprises a substantially non-transparent material.

13. The microelectromechanical device of claim 8, wherein the third surface comprises a substantially transparent material.

14. The microelectromechanical device of claim 8, wherein the third surface contacts the first surface when the second surface is in the first position.

15. The microelectromechanical device of claim 7, wherein the third surface comprises a surface of a member that is located on a central portion of at least one of the first layer and the second layer.

16. A microelectromechanical device, comprising:

a first surface;

a second surface located substantially parallel to the first surface, the second surface movable relative to the first surface between a driven position and an undriven position, wherein the driven position is closer to the first surface than is the undriven position; and

at least one structure on at least one of the first surface and the second surface, wherein the at least one structure is compressed by the first surface and the second surface when the second surface is in the driven position, and wherein the at least one structure provides a force to the second surface when the second surface is in the driven position, the force assisting movement of the second surface from the driven position toward the undriven position.

17. A microelectromechanical device of claim 16, wherein the at least one structure is a spring.

18. A microelectromechanical device of claim 16, wherein the at least one structure comprises a body and a tip extended from the body, the body connected to at least one of the first surface and the second surface, the tip bent away from the surface to which the body is connected when the second surface is in the undriven position.

19. A microelectromechanical device of claim 18, wherein the tip is compressed and substantially flattened when the second surface is in the driven position.

20. A method of making an interferometric modulator, the method comprising:

providing a first layer comprising a first reflective planar portion;

forming a second layer comprising a second reflective planar portion, the second reflective planar portion located substantially parallel to the first reflective planar portion, the second layer movable between a first position and a second position, the first position being a first distance from the first layer, the second position being a second distance from the first layer, the second distance being greater than the first distance; and

forming a member comprising a surface located between the first layer and the second layer, the member defining one or more gap regions between the first layer and the second layer when the second layer is in the first position, the surface comprising a dielectric material which contacts at least one of the first layer and the second layer when the second layer is in the first position,

wherein the second layer in the one or more gap regions does not contact either the first layer or the member.

21. The method of claim 20, wherein the member separates the first layer from the second layer when the second layer is in the first position.

22. The method of claim 20, wherein the member is on at least one of the first layer and second layer.

23. The method of claim 20, wherein the member comprises a bump.

24. The method of claim 20, wherein the member comprises a landing pad.

25. The method of claim 20, wherein the member comprises a spring.

26. The method of claim 20, further comprising forming one or more additional members, wherein each additional member comprises a surface located between the first layer and the second layer.