A NON-CONTACTING ELECTROSTATICALLY-DRIVEN MEMS DEVICE

• US 20060238852A1
• Filed: 04/22/2005
• Published: 10/26/2006
• Est. Priority Date: 04/22/2005
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Strumpell, Mark H.
• Application Number:
  US10/907,992
• Publication Number:
  US 20060238852A1
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

An improved microelectromechanical systems (MEMS) device, which eliminates, or at least reduces, “stiction” is described. The MEMS device includes a central electrode and a pair of outer electrodes formed on a substrate. The central electrode includes a plurality of extensions defining a plurality of grooves interspersed with the extensions. The outer electrodes include a plurality of extensions disposed within the grooves of the central electrode.

Claims

1. A microelectromechanical device, comprising:

a substrate;

a first electrode formed on the substrate, the first electrode having at least one extension extending from a first portion of the first electrode and at least one extension extending from a second portion of the first electrode, the second portion being substantially opposed to the first portion;

a second electrode formed on the substrate substantially adjacent to the first portion of the first electrode, the second electrode having at least one extension extending towards the first electrode; and

a third electrode formed on the substrate substantially adjacent to the second portion of the first electrode, the third electrode having at least one extension extending towards the first electrode;

wherein the at least one extension of the first portion of the first electrode substantially overlaps the at least one extension of the second electrode and the at least one extension of the second portion of the first electrode substantially overlaps the at least one extension of the third electrode.

2. A device according to claim 1, wherein the at least one extension extending from a first portion of the first electrode is a plurality of extensions spaced from one another to define a plurality of grooves interspersed with the plurality of extensions.

3. A device according to claim 2, wherein the at least one extension extending from a second portion of the first electrode is a plurality of extensions spaced from one another to define a plurality of grooves interspersed with the plurality of extensions.

4. A device according to claim 3, wherein the at least one extension of the second electrode is a plurality of extensions disposed within a plurality of grooves corresponding to the first portion of the first electrode.

5. A device according to claim 4, wherein the at least one extension of the third electrode is a plurality of extensions disposed within a plurality of grooves corresponding to the second portion of the first electrode.

6. A device according to claim 3, wherein at least one of the plurality of extensions extending from each of the first and second portions of the first electrode has a polygonal geometric shape.

7. A device according to claim 6, wherein the polygonal geometric shape is selected from the group consisting of a triangle, a square, a rectangle, a parallelogram, a diamond, and a trapezoid.

8. A device according to claim 3, wherein at least one of the plurality of extensions extending from each of the first and second portions of the first electrode has a plane curve geometric shape.

9. A device according to claim 8, wherein the plane curve geometric shape is selected from the group consisting of a circle, a semi-circle, an ellipse, a semi-ellipse, a line, a parabola, and a hyperbola.

10. A device according to claim 3, wherein at least one of the plurality of extensions extending from each of the second and third electrodes has a polygonal geometric shape.

11. A device according to claim 10, wherein the polygonal geometric shape is selected from the group consisting of a triangle, a square, a rectangle, a parallelogram, a diamond, and a trapezoid.

12. A device according to claim 3, wherein at least one of the plurality of extensions extending from each of the second and third electrodes has a plane curve geometric shape.

13. A device according to claim 12, wherein the plane curve geometric shape is selected from the group consisting of a circle, a semi-circle, an ellipse, a semi-ellipse, a line, a parabola, and a hyperbola.

14. A device according to claim 1, further comprising a yoke operatively secured to the substrate, the yoke having a groove formed therein.

15. A device according to claim 14, further comprising a pixel mirror operatively secured to the yoke, the pixel mirror having a downwardly extending post for engagement with the groove formed in the yoke.

16. A device according to claim 1, wherein the first electrode comprises a plurality of electrodes.

17. A microelectromechanical device, comprising:

a substrate;

a first electrode formed on the substrate, the first electrode having a plurality of spaced apart extensions extending from opposing sides of the first electrode, the spaced apart extensions defining a plurality of grooves interspersed with the extensions;

a pair of additional electrodes formed on the substrate adjacent to the opposing sides of the first electrode, the additional electrodes having a plurality of spaced apart extensions disposed within the grooves defined at opposing sides of the first electrode;

wherein the at least one extension of the first portion of the first electrode substantially overlaps the at least one extension of the second electrode and the at least one extension of the second portion of the first electrode substantially overlaps the at least one extension of the third electrode.

18. A device according to claim 17, further comprising a yoke operatively secured to the substrate.

19. A device according to claim 18, further comprising a pixel mirror operatively secured to the yoke.

20. A method for reducing stiction associated with operation of microelectromechanical devices, comprising:

forming a microelectromechanical device to include a first electrode and a pair of electrodes flanking the first electrode, the first electrode interfacing with the pair of electrodes via a plurality extensions disposed within a plurality of grooves defined in the pair of electrodes, wherein the at least one extension of the first portion of the first electrode substantially overlaps the at least one extension of the second electrode and the at least one extension of the second portion of the first electrode substantially overlaps the at least one extension of the third electrode;

whereby the surface area defined at the interface between the first electrode and the pair of electrodes generates an electrostatic force large enough to overcome surface adhesion forces associated with operation of the microelectromechanical device.