Micro-oscillating element provided with torsion bar

• US 7,031,041 B2
• Filed: 02/10/2005
• Issued: 04/18/2006
• Est. Priority Date: 08/14/2002
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Tsuboi, Osamu, Mi, Xiaoyu, Ueda, Satoshi, Sawaki, Ippei
• Primary Examiner(s): Cherry, Euncha P.
• Application Number:
  US11/053,880
• Publication Number:
  US 20050134951A1
• Time in Patent Office: 432 Days
• Field of Search: 359/201, 359/213, 359/214, 359/223, 359224-226
• US Class Current: 359/224.1
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 2203/0109 Bridges
• CPC Class Codes: B81B 2203/0154 Torsion bars
• CPC Class Codes: B81B 2203/058 Rotation out of a plane parallel to the substrate
• CPC Class Codes: B81B 3/007 For controlling stiffness, e.g. ribs
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micro-oscillating element is provided with a frame (113) and a oscillating member (111) connected with the frame (113) via a connector (112). Each connector (112) includes two torsion bars (112a), each torsion bar (112a) being constructed so that the rigidity becomes relatively high toward the frame (113) and relatively low toward the oscillating member (111) by forming a plurality of holes (112b).

Claims

1. A micro-oscillating element, comprising:

a frame; and

an oscillating member connected to the frame via connectors;

wherein each of the connectors includes two torsion bars having an interval in a widthwise direction, the interval becoming larger toward the oscillating member and gradually decreasing toward the frame, each of the torsion bars being provided with rigidity adjustment means.

2. The micro-oscillating element according to claim 1, wherein the rigidity adjustment means is constructed so that the rigidity of each of the torsion bars becomes relatively high toward the frame and relatively low toward the oscillating member.

3. The micro-oscillating element according to claim 2, wherein the rigidity adjustment means is a plurality of holes formed on the torsion bars.

4. The micro-oscillating element according to claim 3, wherein the size of the holes varies so as to become smaller toward the frame and larger toward the oscillating member.

5. The micro-oscillating element according to claim 3, wherein the density of the holes varies so as to become smaller toward the frame and larger toward the oscillating member.

6. The micro-oscillating element according to claim 3, wherein the plurality of holes penetrate the torsion bars in the thickness direction.

7. The micro-oscillating element according to claim 3, wherein the plurality of holes penetrate the torsion bars in the widthwise direction.

8. The micro-oscillating element according to claim 3, wherein a part of the plurality of holes penetrate the torsion bars in the thickness direction, and the rest of the plurality of holes penetrate the torsion bars in the widthwise direction.

9. The micro-oscillating element according to claim 2, wherein the width of the torsion bars varies so as to become larger toward the frame and smaller toward the oscillating member.

10. The micro-oscillating element according to claim 2, wherein the rigidity adjustment means is provided with a plurality of reinforcement ribs projecting toward the widthwise direction of the torsion bars, the interval of those reinforcement ribs varying so as to become smaller toward the frame and larger toward the oscillating member.

11. The micro-oscillating element according to claim 2, wherein the thickness of the torsion bars varies so as to become larger toward the frame and smaller toward the oscillating member.

12. The micro-oscillating element according to claim 2, wherein the rigidity adjustment means is provided with a plurality of reinforcement ribs projecting toward the thickness direction of the torsion bars, the interval of those reinforcement ribs varying so as to become smaller toward the frame and larger toward the oscillating member.

13. The micro-oscillating element according to claim 12, wherein the two torsion bars are shifted from each other in position in the thickness direction.

14. The micro-oscillating element according to claim 1, wherein the frame constitutes an inner frame, the connector is an inner connector which connects the inner frame with the oscillating member, and further an outer frame is connected to the inner frame via an outer connector, each of the outer connectors including at least one outer torsion bars provided with rigidity adjustment means.

15. The micro-oscillating element according to claim 14 wherein the rigidity adjustment means of the outer torsion bar is constructed so that the rigidity of the outer torsion bar becomes relatively high toward the outer frame and relatively low toward the inner frame.

16. The micro-oscillating element according to claim 14, wherein the oscillating axis of the outer connector perpendicularly intersects with the oscillating axis of the inner connector.

17. A micro-mirror unit comprising a micro-oscillating element according to claim 1, wherein the oscillating member includes a mirror section.

18. A micro-oscillating element, comprising:

an inner frame;

an oscillating member connected to the inner frame via inner connectors, each of the inner connectors including at least one inner torsion bar provided with rigidity adjustment means and

an outer frame connected to the inner frame via an outer connector, the outer connector including at least one outer torsion bar provided with rigidity adjustment means.