Microfabricated torsional drive utilizing lateral electrostatic force

• US 7,005,775 B2
• Filed: 05/09/2002
• Issued: 02/28/2006
• Est. Priority Date: 05/09/2001
• Status: Expired due to Fees

• Current Assignee: Chang Feng Wan
• Original Assignee: Chang Feng Wan
• Inventors: Wan, Chang Feng
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US10/142,821
• Publication Number:
  US 20050002084A1
• Time in Patent Office: 1,391 Days
• Field of Search: 310/309, 318/116, 385/18, 359/291, 359/223, 359/224, 359/225, 359/226
• US Class Current: 310/309
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

The present invention is related to a novel micro-electro-mechanical systems (MEMS) torsional drive that is capable of tilting suspended structure such as a micro-mirror for steering light beams in three-dimensional analog fashion, which is suitable for high port count optical switches. The torsional drive has the advantages of allowing large tilt angle, having low drive voltage, and capable of providing a feedback signal for closed-loop control.

Claims

1. A torsional drive, comprising:

a payload plate,

a suspended frame, inner fixed combs,

outer fixed combs,

inner torsion beams and out torsion beams; and

inner movable combs and outer movable combs and posts, wherein said inner movable combs that are attached to said payload plate, are hinged on said suspended frame with torsion beams from near the surface of said inner movable combs, and interdigit with said inner fixed combs slightly, and inner fixed combs and outer movable combs are fixed to said suspended frame, wherein said suspended frame, said inner fixed combs, said outer torsion beams, said outer movable comb, and said posts are electrically grounded and a layer of insulator is deposited thereon.

2. The torsional drive of claim 1 wherein said inner torsion beams are electrically insulated from said suspended frame and said payload plate.

3. The torsional drive of claim 2 wherein said outer hinges are connected to inner movable combs and thin metal lines make electrical connections between the inner movable combs and bond pads on said posts.