Systems and methods for overcoming stiction using a lever

• US 6,625,342 B2
• Filed: 07/03/2001
• Issued: 09/23/2003
• Est. Priority Date: 07/03/2001
• Status: Active Grant

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: Network Photonics, Inc.
• Inventors: Staple, Bevan, Muller, Lilac, Anderson, David Paul
• Primary Examiner(s): Ullah, Akm Enayet
• Assistant Examiner(s): CONNELLY CUSHWA, MICHELLE R
• Application Number:
  US09/898,988
• Publication Number:
  US 20030007720A1
• Time in Patent Office: 812 Days
• Field of Search: 385/16-24, 385/47, 307/112-115, 307/139, 307/143, 359/223-226, 359/291, 310/308-310
• US Class Current: 385/18
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 2203/0181 See-saws
• CPC Class Codes: B81B 3/0016 Arrangements for avoiding sticking of the flexible or moving parts not provided for in groups B81B3/0005 - B81B3/0013
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/29307 components assembled in or forming a solid transparent unitary block, e.g. for facilitating component alignment
• CPC Class Codes: G02B 6/2931 Diffractive element operating in reflection
• 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 6/352 the reflective optical element having a shaped reflective surface, e.g. a reflective element comprising several reflective surfaces or facets that function together
• CPC Class Codes: G02B 6/3546 NxM switch, i.e. a regular array of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/3556 NxM switch, i.e. regular arrays of switches elements of matrix type constellation
• CPC Class Codes: G02B 6/3558 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/3566 involving bending a beam, e.g. with cantilever
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: G02B 6/3598 Switching means directly located between an optoelectronic element and waveguides, including direct displacement of either the element or the waveguide, e.g. optical pulse generation based on changing the optical properties of the medium G02F1/00; optical pulse generation in optical transmitters H04B10/508; optical pulse generation by controlling laser operation H01S3/00

Abstract

A microstructure is provided including a base layer underlying a first and second structural plates. Operation of the microstructure is capable of overcoming stiction. Methods of operation include providing an edge of the first structural plate in contact with a contact point. A second structural plate is deflected in a way that overcomes stiction between the first structural plate and the contact point. Such deflection can include providing a prying force to lift the first structural plate or a hammering force to disturb any stiction related forces at the contact point.

Claims

1. A method for overcoming a stiction force in an electro-mechanical device, wherein the stiction force is between a structural plate and a contact point, the method comprising:

providing a base layer;

providing a first pivot and a second pivot disposed on the base layer;

providing a first structural plate supported by the first pivot and disposed above the base layer, wherein an edge of the first structural plate is in contact with the contact point;

providing a second structural plate supported by the second pivot and disposed above the base layer; and

deflecting the second structural plate to overcome a stiction force between the first structural plate and the contact point.

2. The method of claim 1, wherein the deflecting the second structural plate is caused, at least in part, by a restorative force between the second structural plate and the second pivot.

3. The method of claim 1, the method further comprising;

providing an actuator disposed on the base layer and under the second structural plate; and

activating the actuator to create an electric field force, wherein the deflecting the second structural plate is caused, at least in part, by the electric field force.

4. The method of claim 3, wherein the deflecting the second structural plate is caused, at least in part, by a combination of the electric field force and a restorative force between the second structural plate and the second pivot.

5. The method of claim 1, the method further comprising:

providing a first actuator disposed on the base layer and under the first structural plate;

providing a second actuator disposed on the base layer and under the second structural plate; and

activating the first actuator, wherein the first actuator creates a first electric field force;

activating the second actuator, wherein the second actuator creates a second electric field force, wherein the deflecting the second structural plate is caused, at least in part, by a combination of the second electric field force and a restorative force between the second structural plate and the second pivot; and

wherein the stiction force is overcome by a combination of the deflecting the second structural plate, a restorative force between the first structural plate and the first pivot, and the first electric field force.

6. The method of claim 1, wherein the deflecting the second structural plate comprises moving the second structural plate into contact with the first structural plate.

7. The method of claim 6, wherein the stiction force is caused, at least in part, by a molecule build-up or an adhesion force, and wherein the contact with the first structural plate causes a disturbance in the molecule build-up or adhesion force.

8. The method of claim 7, wherein a combination of a restorative force between the first structural plate and the first pivot and the disturbance in the molecule build-up or adhesion force is sufficient to overcome the stiction force.

9. The method of claim 6, wherein the stiction force is caused, at least in part, by a charge build-up, and wherein the contact with the first structural plate causes a disturbance in the charge build-up.

10. The method of claim 1, the method further comprising:

providing an actuator disposed on the base layer and under the second structural plate; and

activating the actuator to create an electric field force, wherein the deflecting the second structural plate is caused, at least in part, by the electric field force, and wherein a first impact occurs between the first structural plate and the second structural plate;

deactivating the actuator, wherein the second structural plate moves away from the first structural plate; and

reactivating the actuator to create the electric field force, wherein a second impact occurs between the first structural plate and the second structural plate, and wherein a combination of the first impact and the second impact reduces the stiction force.

11. A method for overcoming a stiction force incident at a stop position in a MEMS device, the method comprising:

providing a base layer;

providing a first plate supported by a first pivot, wherein the first plate is disposed above the base layer and the first pivot is disposed on the base layer;

providing a second plate supported by a second pivot, wherein the second plate is disposed above the base layer and the second pivot is disposed on the base layer;

deflecting the first plate and deflecting the second plate to the stop position, wherein at the stop position, the second plate contacts the base layer or a structure thereon and the first plate contacts the second plate; and

wherein the stiction force is overcome by a combination of a first restorative force between the first plate and the first pivot and a second restorative force between the second plate and the second pivot.

12. The method of claim 11, wherein the first plate comprises a mirror.

13. The method of claim 11, wherein the deflecting the first plate comprises activating a first actuator and the deflecting the second plate comprises deflecting the second actuator.

14. The method of claim 13, wherein activating the first actuator comprises applying a voltage to the first actuator.

15. The method of claim 11, the method further comprising:

providing a first actuator disposed beneath the first plate;

providing a second actuator disposed beneath the second plate;

activating the first actuator to create a first actuator force on the first plate;

activating the second actuator to create a second actuator force on the second plate; and

wherein the stiction force is overcome by a combination of the first and second restorative forces, and the first and second actuator forces.

16. A method for overcoming a stiction force trapping a first plate in contact with a base layer or a structure thereon, the first plate included in a MEMS device, the method comprising:

providing the base layer;

providing a first actuator and a second actuator disposed on the base layer;

providing the first plate supported by a first pivot, wherein the first plate is disposed above the first actuator and the first pivot is disposed on the base layer between the first actuator and the second actuator;

providing a second plate supported by a second pivot, wherein the second plate is disposed above the second actuator and the second pivot is dispose on the base layer;

activating the second actuator to cause the second plate to impact the first plate, wherein the impact reduces the stiction force.

17. The method of claim 16, wherein the impact is a first impact, the method further comprising:

deactivating the second actuator, wherein the second plate moves away from the first plate; and

reactivating the second actuator to cause the second plate to impact the first plate for a second time, wherein the second impact further reduces the stiction force.

18. The method of claim 16, the method further comprising:

activating the first actuator to create an actuator force on the first plate, wherein the actuator force on the first plate is in opposition to the stiction force.

19. The method of claim 18, wherein the stiction force is overcome by a combination of the impact and the actuator force.

20. The method of claim 18, wherein the stiction force is overcome by a combination of the impact, the actuator force, and a restorative force between the first plate and the first pivot.

21. The method of claim 16, wherein the first plate comprises a mirror.

22. The method of claim 16, wherein the second plate comprises a mirror.

23. An apparatus adapted for overcoming a stiction force, wherein the stiction force is between a structural plate and a contact point, the apparatus comprising:

a base layer;

a first pivot and a second pivot disposed on the base layer;

a first structural plate supported by the first pivot and disposed above the base layer, wherein an edge of the first structural plate is in contact with the contact point;

a second structural plate supported by the second pivot and disposed above the base layer; and

wherein the second structural plate is movable to overcome a stiction force between the first structural plate and the contact point.

24. The apparatus of claim 23, the apparatus further comprising:

a first actuator for deflecting the first structural plate;

a second actuator for deflecting the second structural plate; and

wherein the first and second actuators are electrically coupled.

25. The apparatus of claim 24, wherein the first actuator is operable to deflect the first structural plate toward the base layer at a position away from the second structural plate, the apparatus further comprising:

a third actuator operable to deflect the first structural plate toward the base layer at a position near the second structural plate.

26. The apparatus of claim 24, wherein activation of the first actuator and the second actuator causes both the first structural plate and the second structural plate to deflect away from the contact point.

27. A MEMS device adapted for overcoming a stiction force incident at a stop position, the device comprising:

a base layer;

a first plate supported by a first pivot, wherein the first plate is disposed above the base layer and the first pivot is disposed on the base layer;

a second plate supported by a second pivot, wherein the second plate is disposed above the base layer and the second pivot is disposed on the base layer;

a first actuator for deflecting the first plate and a second actuator for deflecting the second plate, wherein the first actuator is electrically connected to the second actuator; and

wherein energizing the first and second actuators causes the first plate to deflect away from the second plate and the second plate to deflect away from the first plate, thereby overcoming the stiction force.

28. The device of claim 27, the device further comprising:

a contact position at which stiction forces trap either of the first plate or the second plate disposed between the first pivot and the second pivot, wherein energizing the first and second actuators causes the first plate and the second plate to deflect away from the contact position.

29. The device of claim 27, wherein the first plate contacts the second plate at a position between the first pivot and the second pivot.