Systems and methods for overcoming stiction

• US 6,856,068 B2
• Filed: 02/28/2002
• Issued: 02/15/2005
• Est. Priority Date: 02/28/2002
• Status: Expired due to Fees

• Current Assignee: Altera Corporation (Intel Corporation)
• Original Assignee: PTS Corporation
• Inventors: Miller, David, Anderson, Robert L., Muller, Lilac
• Primary Examiner(s): Dougherty, Thomas M.
• Application Number:
  US10/087,040
• Publication Number:
  US 20030160540A1
• Time in Patent Office: 1,083 Days
• Field of Search: 310/309, 310/311, 310/328, 359/291, 359/225, 359/295, 385/18, 335/79
• US Class Current: 310/311
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 1/00968 Methods for breaking the stiction bond
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/3512 the optical element being reflective, e.g. mirror
• 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 6/3548 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 6/3564 Mechanical details of the actuation mechanism associated with the moving element or mounting mechanism details
• CPC Class Codes: G02B 6/3568 characterised by the actuating force
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• 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: H02N 1/002 Electrostatic motors
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence

Abstract

A number of methods and systems for overcoming stiction are provided. The systems include electro-mechanical systems capable of exerting a variety of forces upon areas prone to stiction. The systems can be MEMS arrays or other types of devices where stiction related forces occur. The methods include a variety of ways of causing movement in areas prone to stiction forces. Such movement can be vibrational in nature and is sufficient to overcome stiction, allowing a trapped element to be moved to a desired location.

Claims

1. An electo-mechanical system capable of overcoming stiction forces through localized vibration, the system comprising:

a base layer having a surface;

a device supported above the surface by a pivot, wherein the device is movable along a movement path;

a stop located at a contact position along the movement path, wherein the device contacts the stop at the contact position, and wherein a stiction force between the device and the stop exits at the contact position; and

a vibration element operable to cause a vibration at or near the contact position, the vibration element having a vibration actuator, wherein the vibration disrupts the stiction force.

2. The system of claim 1, the system further comprising an device actuator, wherein the device actuator is operable to cause the device to move along the movement path.

3. The system of claim 1, wherein the device is a structural plate, comprising a micro mirror.

4. The system of claim 1, wherein the stop comprises an area of the base layer.

5. The system of claim 4, wherein the vibration element is a mechanical structure operable to repeatedly contact the device at or near the contact point.

6. The system of claim 1, wherein the vibration element comprises a device actuator, wherein the device actuator is operable to cause the device to move along the movement path.

7. The system of claim 1, wherein the vibration element is integral to the device.

8. The system of claim 1, wherein the device is a first device, the pivot is a first pivot, the stop is a first stop, the contact position is a first contact position, the movement path is a first movement path, and the vibration device is a first vibration device, the system further comprising:

at least a second device and a second pivot, wherein the second device is supported above the surface by the second pivot, and wherein the second device is movable along a second movement path;

at least a second stop located at a second contact position along the second movement path, wherein the second device contacts the second stop at the second contact position, and wherein the contact between the second device and the second stop is susceptible to a stiction force;

at least a second vibration element operable to cause a vibration at or near the second contact position, wherein the vibration disrupts the stiction force; and

wherein the first and second vibration elements are electrically connected such that the first and second vibration elements are activated together.

9. The system of claim 1, wherein the vibration element comprises an actuator and the device comprises a structural plate and wherein the actuator is activated by a force that creates a movement of the stop relative to the structural plate, wherein the movement is sufficient to overcome stiction forces between the structural plate and the stop.

10. The system of claim 9, wherein activating the actuator with a force causes the stop to displace from a static position to a displaced position, and wherein the movement results from elastic forces associated with the stop which cause the stop to displace from the displaced position to the static position when the actuator is de-activated.

11. The system of claim 10, wherein the movement comprises an oscillation of the stop.

12. The system of claim 11, wherein the oscillation comprises displacement of the stop from the placed position passed the static position to an overshoot position and back to the static position.

13. The system of claim 9, wherein the structural plate is supported above the base layer by a pivot and the stop is disposed over the base layer.

14. The system of claim 13, the system further comprising a micro-mirror disposed on the structural plate.

15. The system of claim 13, wherein the actuator is a first actuator, the system further comprising a second actuator, wherein application of a DC voltage to the second actuator cause the structural plate to displace and contact the stop.

16. The system of claim 1, wherein the stop comprises a mechanical stop, the device comprises a structural plate, and the vibration element comprises an actuator, and wherein application of a DC voltage to the actuator causes the mechanical stop to move relative to the structural plate from a static position to a displaced position, and wherein removal of the DC voltage causes a movement of the mechanical stop from the displaced position to the static position, and wherein the movement is sufficient to overcome stiction forces between the structural plate and the mechanical stop.

17. The system of claim 16, wherein the movement comprises an oscillation of the mechanical stop.

18. The system of claim 17, wherein the oscillation comprises displacement of the mechanical stop from the displaced position passed the static position to an overshoot position and back to the static position.

19. The system of claim 16, wherein the structural plate is supported above base layer by a pivot and the mechanical stop is disposed over the base layer.

20. The system of claim 19, wherein the actuator is a first actuator, the system further comprising a second actuator, wherein application of a force to the second actuator causes the structural plate to deflect into contact with the mechanical stop.

21. The system of claim 16, wherein the system comprises an optical routing apparatus comprising a moveable micro-mirror.

22. The system of claim 1, wherein the vibration element comprises an actuator and the device comprises a structural plate, and wherein the actuator is activated by an alternating force that creates an oscillating movement of the stop relative to the structural plate, wherein the oscillating movement is sufficient to overcome stiction forces between the structural plate and the stop.

23. The system of claim 22, wherein the alternating force is an AC voltage or a pulsed DC voltage.

24. The system of claim 22, wherein activating the actuator with an alternating force causes the stop to displace to a displaced position when the alternating force is at a first potential, and wherein an elastic force associated with the stop causes the stop to displace toward a static position when the alternating force is at a second potential.

25. The system of claim 24, wherein the oscillating movement results from displacing the stop to the displaced position and returning the stop toward the static position.

26. The system of claim 25, wherein the oscillating movement oscillates at a frequency at or about the frequency of the alternating force.

27. The system of claim 22, wherein the structural plate is supported above the base layer by a pivot and the stop is disposed over the base layer.

28. The system of claim 27, wherein the actuator is a first actuator, the system further comprising a second actuator, wherein application of a voltage to the second actuator cause the structural plate to displace and contact the stop.