Micro-electro-mechanical systems micromirrors and micromirror arrays

• US 10,551,613 B2
• Filed: 05/04/2015
• Issued: 02/04/2020
• Est. Priority Date: 10/20/2010
• Status: Active Grant

• Current Assignee: Preciseley Microtechnology Corporation
• Original Assignee: Preciseley Microtechnology Corporation
• Inventors: Zhou, Tiansheng
• Primary Examiner(s): Kakalec, Kimberly N.
• Application Number:
  US14/702,874
• Publication Number:
  US 20150234176A1
• Time in Patent Office: 1,737 Days
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0136 Comb structures
• CPC Class Codes: B81C 1/00603 Aligning features and geometries on both sides of a substrate, e.g. when double side etching
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G06F 16/958 Organisation or management of web site content, e.g. publishing, maintaining pages or automatic linking

Abstract

A micromirror and micromirror array may have a first stationary structure, and a mirror structure connected to a first pivoting structure that pivots the mirror structure relative to the first stationary structure about a first axis of rotation. A first comb drive pivots the mirror structure about the first axis of rotation. The first comb drive has a first portion attached to the stationary structure and a second portion attached to the mirror structure, the first portion being electrically isolated from the second portion. The micromirror or micromirror array may be mounted to a Through Silicon Via (TSV) wafer having electrical connections that extend between a first side and a second side of the TSV wafer such that the first and second portions of each comb drive are electrically connected to the electrical connections.

Claims

1. A micromirror comprising:

a support structure and a micromirror structure;

a pivot structure connecting the support structure to the micromirror structure, the pivot structure having an axis of rotation; and

a vertical comb drive having a first portion carried by the support structure and a second portion carried by the micromirror structure and electrically isolated from the first portion, such that an electrical potential difference applied to the first portion relative to the second portion drives the micromirror structure about the axis of rotation;

wherein;

each of the first portion and the second portion comprise a first end and a second end spaced from the first end in a direction parallel to the axis of rotation, and a plurality of comb fingers that extend between the first end and the second end;

the micromirror structure carries a mirror face, the mirror face being reflective to reflect optical signals, and the mirror face being in a common plane with each of the pivot structure and the second portion of the vertical comb drive; and

two or more structural elements connecting the plurality of comb fingers of the second portion, the two or more structural elements being spaced apart along a length of the comb fingers to provide intermediate support to the comb fingers to resist bending, and at least one of the two or more structural elements being spaced from the first end and second end of the second portion.

2. The micromirror of claim 1, wherein the direction of the comb fingers is deflected in the direction of the axis of rotation along a radius of curvature that is equivalent to the spacing between the fingers and the axis of rotation.

3. The micromirror of claim 2, wherein the comb fingers are curved along the radius of curvature.

4. The micromirror of claim 2, wherein the comb fingers comprise straight segments that are angled along one or more tangent to the radius of curvature.

5. The micromirror of claim 1, wherein the comb fingers of the second portion of the comb drive are set within an outer frame, the outer frame stabilizing the comb fingers.

6. The micromirror of claim 1, wherein the comb fingers of the second portion are offset between the comb fingers of the first portion in a direction perpendicular to the axis of rotation.

7. The micromirror of claim 1, wherein the comb fingers have a length, and at least a portion of the comb fingers of the first portion are tapered along the length.

8. The micromirror of claim 1, wherein the pivot structure comprises a resilient hinge.

9. The micromirror of claim 8, wherein the resilient hinge comprises a serpentine, structure.

10. The micromirror of claim 8, wherein the resilient hinge comprises a first beam and a second beam that is parallel to the first beam.

11. The micromirror of claim 8, wherein the resilient hinge comprises a first beam and a second beam that is angled relative to the first beam.

12. The micromirror of claim 8, wherein the resilient hinge has a tapering thickness.

13. The micromirror of claim 1, wherein a plurality of comb fingers of the second portion are connected by a structural support that traverses the plurality of comb fingers of the second portion, the structural support being spaced from or extending outward from the micromirror structure.

14. The micromirror of claim 1, wherein the at least one structural element is positioned on an upper surface of the comb fingers of the second portion such that the comb fingers of the second portion extend toward the comb fingers of the first portion relative to the structural element.

15. The micromirror of claim 1, wherein the at least one structural element has a height that is equivalent to and coterminous with a height of the comb fingers of the second portion.

16. The micromirror of claim 1, wherein the micromirror structure comprises:

a gimbal structure connected between the support structure and a mirror element, the gimbal structure moves about the axis of rotation relative to the support structure, and the mirror element is pivotally mounted to the gimbal structure about a second axis of rotation; and

a second comb drive that drives the mirror element about the second axis of rotation.

17. The micromirror of claim 1, wherein the micromirror structure comprises a rear face opposite the mirror face, and the rear face comprises a pattern of cavities that reduces a mass of the micromirror structure.

18. The micromirror of claim 1, wherein the two or more separate structural elements is three or more separate structural elements that connect the plurality of comb fingers of the second portion, the three or more structural elements being spaced apart along a length of the comb fingers, and at least one structural element being spaced from the first end and second end of the second portion.

19. A micromirror comprising:

a stationary structure;

a mirror structure, the mirror structure being pivotally connected to the stationary structure by a pivoting structure having an axis of rotation the mirror structure carrying a mirror face, the mirror face being reflective to reflect optical signals;

a comb drive pivoting the mirror structure about the axis of rotation, the first comb drive having a first set of comb fingers carried by the stationary structure and a second set of comb fingers carried by the mirror structure, each of the first set and the second set of comb fingers extending between a first end and a second end spaced from the first end in a direction parallel to the axis of rotation, the mirror face being in a common plane with each of the pivoting structure and the second set of comb fingers; and

two or more structural elements that connect a plurality of comb fingers in the second set of comb fingers, the two or more structural elements being spaced apart along a length of the comb fingers to provide intermediate support to the comb fingers to resist bending, and at least one structural element of the two or more structural elements being spaced from the first end and the second end of the second set of comb fingers.

20. The micromirror of claim 19, wherein the at least one structural element maintains a physical separation from the first set of comb fingers as the mirror structure pivots.

21. The micromirror of claim 19, wherein the comb fingers of the first and second sets of comb drive fingers extend in a direction that is parallel to the axis of rotation.

22. The micromirror of claim 19, wherein the at least one structural element is positioned on an upper surface of the second set of comb fingers such that the second set of comb fingers extends toward the first set of comb fingers relative to the at least one structural element.

23. An array of micromirrors comprising:

a plurality of micromirrors arranged in an array, and each micromirror comprising;

a support structure and a micromirror structure;

a pivot structure connecting the support structure to the micromirror structure, the pivot structure having an axis of rotation and the micromirror structure comprising a mirror face,

a vertical comb drive having a first portion carried by the support structure and a second portion carried by the micromirror structure and electrically isolated from the first portion, such that an electrical potential difference applied to the first portion relative to the second portion drives the micromirror structure about the axis of rotation, and the mirror face of the micromirror structure being in a common plane with each of the pivot structure and the second portion of the vertical comb drive;

each of the first portion and the second portion comprise a first end and a second end that is spaced from the first end in a direction parallel to the axis of rotation, and comb fingers that extend between the first end and the second end; and

two or more structural elements connecting a plurality of the comb fingers of the second portion, the two or more structural elements being spaced apart along a length of the comb fingers to provide intermediate support to the comb fingers to resist binding, and at least one structural element of the two or more structural elements being spaced from the first end and second end of the second portion.

24. The array of claim 23, wherein the array comprises at least one row of micromirrors, the micromirror structure of each micromirror in the row being immediately adjacent at least one other micromirror structure.

25. An array of micromirrors comprising:

a plurality of micromirrors arranged in an array, and each micromirror comprising;

a stationary structure;

a mirror structure, the mirror structure being pivotally connected to the stationary structure by a pivoting structure having an axis of rotation and comprising a mirror face, and the mirror face being reflective to reflect optical signals;

a comb drive pivoting the mirror structure about the axis of rotation, and the first comb drive having a first set of comb fingers carried by the stationary structure and a second set of comb fingers carried by the mirror structure, each of the first set and the second set of comb fingers extending between a first end and a second end that is spaced from the first end in a direction parallel to the axis of rotation; and

two or more structural elements that connect a plurality of comb fingers in the second set of comb fingers, the two or more structural elements being spaced apart along a length of the comb fingers to provide intermediate support to the comb fingers to resist bending, and at least one structural element of the two or more structural elements being spaced from the first end and the second end of the second set of comb fingers, and

the mirror face of the mirror structure being in a common plane with each of the pivoting structure and the second set of comb fingers.

26. The array of claim 25, wherein the array comprises at least one row of micromirrors, the micromirror structure of each micromirror in the row being immediately adjacent at least one other micromirror structure.