Micro-electro-mechanical-system micromirrors for high fill factor arrays and method therefore

• US 7,911,672 B2
• Filed: 12/05/2007
• Issued: 03/22/2011
• Est. Priority Date: 12/26/2006
• Status: Active Grant

• Current Assignee: Preciseley Microtechnology Corporation
• Original Assignee: Tiansheng Zhou
• Inventors: Zhou, Tiansheng
• Primary Examiner(s): Phan; James
• Application Number:
  US11/950,721
• Publication Number:
  US 20080151345A1
• Time in Patent Office: 1,203 Days
• Field of Search: 3591991-1992, 359/200.6, 3592241-2242
• US Class Current: 359/224.1
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 3/004 Angular deflection
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micro-electro-mechanical-system (MEMS) micromirror for use in high fill factor arrays which includes at least one stationary body and a movable body. The movable body has opposed ends and is secured to the stationary body at each of the opposed ends by a resilient primary axis pivot. A mirror support is supported by and movable with the movable body. The mirror support has a first unfettered side and a second unfettered side. A primary axis actuator is provided including a fixed portion connected to the stationary body, and a movable portion corrected to the movable body. The movable portion is adapted to move away from the fixed portion in response to an electrical potential difference between the fixed portion and the movable portion, such that the movable body rotates about the primary axis resilient pivot. A mirror is supported by the mirror support.

Claims

1. A micro-electro-mechanical-system micromirror for use in high fill factor arrays, comprising:

at least one stationary body;

a movable body having opposed sides and being secured to the stationary body at each of the opposed sides by a resilient primary axis pivot;

a mirror support supported by and movable with the movable body, the mirror support having a first unfettered side and a second unfettered side;

a primary axis actuator comprising a fixed portion connected to the stationary body, and a movable portion connected to the movable body, the movable portion being movable relative to the fixed portion in response to an electrical potential difference between the fixed portion and the movable portion, such that the movable body rotates about the primary axis resilient pivot;

a secondary axis resilient pivot positioned between the mirror support and the movable body;

a secondary axis actuator, the secondary axis actuator comprising a fixed portion connected to the movable body, and a movable portion connected to the mirror support, the movable portion moving away from the fixed portion in response to an electrical potential difference between the fixed portion and the movable portion, such that the mirror support rotates about the secondary axis resilient pivot; and

a mirror supported by the mirror support.

2. The micro-electro-mechanical-system micromirror of claim 1, wherein the at least one stationary body is mounted to a carrier wafer, the at least one stationary body comprising anchors for mounting the resilient primary axis pivot and the fixed portion of the primary axis actuator to the carrier wafer.

3. The micro-electro-mechanical-system micromirror of claim 2, wherein the carrier wafer is a Pyrex glass wafer or a silicon wafer.

4. The micro-electro-mechanical-system micromirror of claim 2, wherein the carrier wafer is etched to form supporting structures, the anchors being mounted to the supporting structures and to form a cavity or through hole below at least one of the mirror support and the movable body.

5. The micro-electro-mechanical-system micromirror of claim 1, wherein the mirror support extends in a cantilever fashion from one end of the movable body and has a remote unfettered end.

6. The micro-electro-mechanical-system micromirror of claim 5, wherein at least three of the micro-electro-mechanical-system micromirrors are arranged in an array with each body positioned in parallel spaced relation with the first unfettered side of a mirror support of a first of the at least three micro-electro-mechanical-system micromirrors is positioned immediately next to the second unfettered side of a mirror support for a second of the at least three micro-electro-mechanical-system micromirrors and the second unfettered side of the first mirror support of the first of the at least three micro-electro-mechanical-system micromirrors positioned immediately next to the first unfettered side of a mirror support for a third of the at least three micro-electro-mechanical-system micromirrors.

7. The micro-electro-mechanical-system micromirror of claim 5, wherein at least three of the micro-electro-mechanical-system micromirrors are arranged in an array with each body positioned along parallel axes in an alternating pattern, with the first unfettered side of a mirror support for a first of the at least three micro-electro-mechanical-system micromirrors positioned immediately next to the first unfettered side of a mirror support for a second of the at least three micro-electro-mechanical-system micromirrors and the second unfettered side of the mirror support for the first of the at least three micro-electro-mechanical-system micromirrors is positioned immediately next to the second unfettered side of a mirror support for a third of the at least three micro-electro-mechanical-system micromirrors.

8. The micro-electro-mechanical-system micromirror of claim 5, wherein two of the micro-electro-mechanical-system micromirrors are arranged in end to end relation with the remote unfettered end of the mirror support for a first of the two micro-electro-mechanical-system micromirrors positioned immediately next to the remote unfettered end of the mirror support for a second of the two micro-electro-mechanical-system micromirrors.

9. The micro-electro-mechanical-system micromirror of claim 5, wherein at least three of the micro-electro-mechanical-system micromirrors are arranged in an array with each body positioned in parallel spaced relation with the first unfettered side of a mirror support of a first of the at least three micro-electro-mechanical-system micromirrors positioned immediately next to the second unfettered side of a mirror support for a second of the at least three micro-electro-mechanical-system micromirrors and the second unfettered side of the first mirror support of the first of the at least three micro-electro-mechanical-system micromirrors is positioned immediately next to the first unfettered side of a mirror support for a third of the at least three micro-electro-mechanical-system micromirrors and each of the at least three micro-electro-mechanical-system micromirror are arranged in end to end relation with other micro-electro-mechanical-system micromirror with the remote unfettered end of the mirror support for each of the at least three micro-electro-mechanical-system micromirrors being positioned immediately next to the remote unfettered end of the mirror support of other micro-electro-mechanical-system micromirror.

10. The micro-electro-mechanical-system micromirror of claim 1, wherein at least one of the primary axis actuator and the secondary axis actuator is a vertical combdrive actuator.

11. The micro-electro-mechanical-system micromirror of claim 1, wherein the at least one stationary body is mounted to a carrier wafer, the at least one stationary body comprising more than one anchor, the fixed portion of the secondary axis actuator being electrically connected to an electrode on the carrier wafer, the movable portion of the secondary axis being electrically connected to another electrode on the carrier wafer.

12. The micro-electro-mechanical-system micromirror of claim 11, the carrier wafer having supporting structures, the anchors being connected to the supporting structures, wherein the electrodes are formed on top of the supporting structures.

13. The micro-electro-mechanical-system micromirror of claim 1, wherein at least one of the primary axis actuator and the secondary axis actuator is a parallel plate electrostatic actuator.

14. The micro-electro-mechanical-system micromirror of claim 1, wherein the micromirror apparatus is etched from a single silicon wafer, with the primary axis actuator being electrically isolated from the secondary axis actuator.

15. The micro-electro-mechanical-system micromirror of claim 14, wherein the primary axis actuator and the secondary axis actuator are connected to an actuation electrical signal source by electrodes on the carrier wafer.

16. The micro-electro-mechanical-system micromirror of claim 14, wherein the primary axis actuator and the secondary axis actuator are electrically isolated by a trench filled with dielectric material.

17. The micro-electro-mechanical-system micromirror of claim 1, wherein each of the primary axis resilient pivot and the secondary axis resilient pivot are one of V-shaped, wedge-shaped, or parallel bands.

18. The micro-electro-mechanical-system micromirror of claim 1, wherein at least three of the micro-electro-mechanical-system micromirrors are arranged in an array with each body positioned in parallel spaced relation with the first unfettered side of a mirror support of a first of the at least three micro-electro-mechanical-system micromirrors positioned immediately next to the second unfettered side of a mirror support for a second of the at least three micro-electro-mechanical-system micromirrors and the second unfettered side of the first mirror support of the first of the at least three micro-electro-mechanical-system micromirrors positioned immediately next to the first unfettered side of a mirror support for a third of the at least three micro-electro-mechanical-system micromirrors.

19. The micro-electro-mechanical-system micromirror of claim 1, wherein the primary axis actuator comprises more than one vertical combdrive actuators, at least one of the vertical combdrive actuators being electrically isolated from the other vertical combdrive actuators such that the electrically isolated combdrive actuator acts as a position sensor for the primary axis actuator.

20. The micro-electro-mechanical-system micromirror of claim 19, wherein the capacitance of the electrically isolated combdrive actuator is related to the position of the primary axis actuator.