MEMS actuator assembly for optical switch

• US 8,353,600 B1
• Filed: 06/23/2010
• Issued: 01/15/2013
• Est. Priority Date: 06/23/2010
• Status: Active Grant

• Current Assignee: Advanced Numicro Systems, Inc.
• Original Assignee: Advanced Numicro Systems, Inc.
• Inventors: Fu, Yee-Chung
• Primary Examiner(s): CHERRY, EUNCHA P
• Application Number:
  US12/822,180
• Time in Patent Office: 937 Days
• Field of Search: 3592231-2261, 359/290, 359/291, 359/871, 359/872
• US Class Current: 359/849
• CPC Class Codes: B81B 2201/033 Comb drives
• CPC Class Codes: B81B 2201/045 Optical switches
• CPC Class Codes: B81B 3/0021 Transducers for transforming electrical into mechanical energy or vice versa dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/101 with both horizontal and vertical deflecting means, e.g. raster or XY scanners colour television using laser beams scanning a display screen H04N9/3129
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841

Abstract

A micro-electro-mechanical system (MEMS) actuator assembly includes a mirror and four actuators. Each actuator includes a lever pivotable about a fulcrum axis. The inner end of each lever is coupled to one side of the mirror. Force is applied to one outer end of the levers to move one side of the mirror, which positions the mirror in one of four positions. Force is applied to two outer ends of the levers to move two sides of the mirror, which positions the mirror in one of four additional positions.

Claims

1. A micro-electro-mechanical system (MEMS) actuator assembly, comprising:

a mirror;

a first actuator, comprising;

a first plurality of stationary comb teeth;

a first lever pivotable about a first fulcrum axis, the first lever having;

a first inner end hingedly coupled to a first side of the mirror; and

a first outer end comprising a first plurality of movable comb teeth interdigitated out of plane with the first plurality of stationary comb teeth to actuate the first lever;

a second actuator, comprising;

a second plurality of stationary comb teeth;

a second lever pivotable about a second fulcrum axis, the second lever having;

a second inner end hingedly coupled to a second side of the mirror; and

a second outer end comprising a second plurality of movable comb teeth interdigitated out of plane with the second plurality of stationary comb teeth to actuate the second lever;

a third actuator, comprising;

a third plurality of stationary comb teeth;

a third lever pivotable about a third fulcrum axis, the third lever having;

a third inner end hingedly coupled to a third side of the mirror; and

a third outer end comprising a third plurality of movable comb teeth interdigitated out of plane with the third plurality of stationary comb teeth to actuate the third lever; and

a fourth actuator, comprising;

a fourth plurality of stationary comb teethe

a fourth lever pivotable about a fourth fulcrum axis, the fourth lever having;

a fourth inner end hingedly coupled to a fourth side of the mirror; and

a fourth outer end comprising a fourth plurality of movable comb teeth interdigitated out of plane with the fourth plurality of stationary comb teeth to actuate the fourth lever.

2. The assembly of claim 1, further comprising:

a first anchor;

a second anchor, wherein the first lever is connected by first hinges along the first fulcrum axis to the first and the second anchors;

a third anchor, wherein the second lever is connected by second hinges along the second fulcrum axis to the second and the third anchors; and

a fourth anchor, wherein the third lever is connected by third hinges along the third fulcrum axis to the third and the fourth anchors, and the fourth lever is connected by fourth hinges along the fourth fulcrum axis to the fourth and the first anchors.

3. The assembly of claim 1, wherein the first, the second, the third, and the fourth pluralities of movable comb teeth are located above the first, the second, the third, and the fourth pluralities of stationary comb teeth.

4. The assembly of claim 1, further comprising:

a first voltage source electrically coupled to the first plurality of stationary comb teeth;

a second voltage source electrically coupled to the second plurality of stationary comb teeth;

a third voltage source electrically coupled to the third plurality of stationary comb teeth;

a fourth voltage source electrically coupled to the fourth plurality of stationary comb teeth; and

a fifth voltage source electrically coupled to the first, the second, the third, and the fourth pluralities of movable comb teeth.

5. The assembly of claim 4, wherein the mirror and the first, the second, the third, and the fourth pluralities of movable comb teeth are electrically coupled.

6. The assembly of claim 4, further comprising

a controller coupled to the first, the second, the third, the fourth, and the fifth voltage sources, wherein the controller is configured to turn on:

the first and the fifth voltage sources to position the mirror in a first position;

the second and the fifth voltage sources to position the mirror in a second position;

the third and the fifth voltage sources to position the mirror in a third position;

the fourth and the fifth voltage sources to position the mirror in a fourth position;

the first, the second, and the fifth voltage sources to position the mirror in a fifth position;

the second, the third, and the fifth voltage sources to position the mirror in a sixth position;

the third, the fourth, and the fifth voltage sources to position the mirror in a seventh position; and

the first, the fourth, and the fifth voltage sources to position the mirror in an eighth position.

7. The assembly of claim 1, wherein each inner end is coupled by a hinge to a corresponding side, the hinge allowing rotation about a first hinge axis parallel to a corresponding fulcrum axis and rotation about a second hinge axis along a length of a corresponding lever.

8. The assembly of claim 1, wherein the first, the second, the third, and the fourth inner ends are hingedly coupled to the mirror at evenly spaced out cyclic points about a center of the mirror.

9. The assembly of claim 8, wherein the mirror comprises:

a mirror frame, wherein the first, the second, the third, and the fourth inner ends are hingedly coupled to the mirror frame;

a mirror body within the mirror frame; and

springs connecting the mirror body to the mirror frame.

10. The assembly of claim 9, wherein the springs are located at evenly spaced-out cyclic positions about the mirror center, and the springs are evenly spaced-out from the cyclic points where the first, the second, the third, and the fourth inner ends are hingedly coupled to the mirror frame.

11. A method for operating a micro-electro-mechanical system (MEMS) actuator assembly, comprising:

applying one or more vertical forces on one or more outer ends of one or more levers, each pivotable about a fulcrum axis, to move one or more sides of a mirror hingedly coupled to one or more inner ends of the one or more levers to position the mirror in one of a plurality of positions.

12. The method of claim 11, wherein said applying one or more vertical force on one or more outer ends of one or more levers comprises:

applying a first vertical force on a first outer end of a first lever pivotable about a first fulcrum axis to move a first side of a mirror hingedly coupled to a first inner end of the first lever to position the mirror in a first position;

applying a second vertical force on a second outer end of a second lever pivotable about a second fulcrum axis to move a second side of the mirror hingedly coupled to a second inner end of the second lever to position the mirror in a second position;

applying a third vertical force on a third outer end of a third lever pivotable about a third fulcrum axis to move a third side of the mirror hingedly coupled to a third inner end of the third lever to position the mirror in a third position; and

applying a forth vertical force on a fourth outer end of a fourth lever pivotable about a fourth fulcrum axis to move a fourth side of the mirror hingedly coupled to a fourth inner end of the fourth lever to position the mirror in a fourth position.

13. The method of claim 12, wherein

said applying a first vertical force on the first outer end of the first lever comprises providing a first voltage difference between a first plurality of movable comb teeth at the first outer end of the first lever and a first plurality of stationary comb teeth;

said applying a second vertical force on the second outer end of the second lever comprises providing a second voltage difference between a second plurality of movable comb teeth at the second outer end of the second lever and a second plurality of stationary comb teeth;

said applying a third vertical force on the third outer end of the third lever comprises providing a third voltage difference between a third plurality of movable comb teeth at the third outer end of the third lever and a third plurality of stationary comb teeth; and

said applying a fourth vertical force on the fourth outer end of the fourth lever comprises providing a fourth voltage difference between a fourth plurality of movable comb teeth at the fourth outer end of the fourth lever and a fourth plurality of stationary comb teeth.

14. The method of claim 12, wherein said applying one or more vertical forces on one or more outer ends of one or more levers further comprises:

applying a first plurality of vertical forces on the first and the second outer ends of the first and the second levers to move the first and the second sides of the mirror to position the mirror in a fifth position;

applying a second plurality of vertical forces on the second and the third outer ends of the second and the third levers to move the second and the third sides of the mirror to position the mirror in a sixth position;

applying a third plurality of vertical forces on the third and the fourth ends of the third and the fourth levers to move the third and the fourth sides of the mirror to position the mirror in a seventh position; and

applying a fourth plurality of vertical forces on the first and the fourth outer ends of the first and the fourth levers to move the first and the fourth sides of the mirror to position the mirror in an eighth position.

15. The method of claim 14, wherein:

said applying a first vertical force on the first outer end of the first lever comprises providing a first voltage difference between a first plurality of movable comb teeth at the first outer end of the first lever and a first plurality of stationary comb teeth;

said applying a second vertical force on the second outer end of the second lever comprises providing a second voltage difference between a second plurality of movable comb teeth at the second outer end of the second lever and a second plurality of stationary comb teeth;

said applying a third vertical force on the third outer end of the third lever comprises providing a third voltage difference between a third plurality of movable comb teeth at the third outer end of the third lever and a third plurality of stationary comb teeth;

said applying a fourth vertical force on the fourth outer end of the fourth lever comprises providing a fourth voltage difference between a fourth plurality of movable comb teeth at the fourth outer end of the fourth lever and a fourth plurality of stationary comb teeth;

said applying a first plurality of vertical forces on the first and the second outer ends of the first and the second levers comprises providing the first and the second voltage differences;

said applying a second plurality of vertical forces on the second and the third outer ends of the second and the third levers comprises providing the second and the third voltage differences;

said applying a third plurality of vertical forces on the third and the forth outer ends of the third and the fourth levers comprises providing the third and the fourth voltage differences; and

said applying a fourth plurality of vertical forces on the first and the fourth outer ends of the first and the fourth levers comprises providing the first and the fourth voltage differences.

16. The method of claim 15, wherein:

providing one or two of the first, the second, the third, and the fourth voltage differences comprises grounding the first, the second, the third, and the fourth pluralities of movable comb teeth and providing a voltage to one or two of the first, the second, the third, and the fourth pluralities of stationary comb teeth.