Capacitively coupled micromirror

• US 7,119,940 B2
• Filed: 06/14/2005
• Issued: 10/10/2006
• Est. Priority Date: 12/28/2000
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Knipe, Richard L.
• Primary Examiner(s): Mack, Ricky
• Assistant Examiner(s): CHOI, WILLIAM C
• Application Number:
  US11/152,794
• Publication Number:
  US 20050243404A1
• Time in Patent Office: 483 Days
• Field of Search: 359/224, 359/225, 359290-292, 359/295, 359/298, 359/872, 345/31, 345/55, 345/84, 345/85
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

A capacitively coupled microelectromechanical device and method of operation. The micromechanical device comprises: a semiconductor substrate; a member operable to deflect about a torsion axis to either of at least two states; and a switch driven for selectively connecting the member to a voltage signal. When a logic high signal is stored on the memory capacitor 308, the mirror transistor 310 is turned on, grounding the mirror structure 312. When a logic low signal is stored on the memory capacitor 308, the mirror transistor 310 is turned off, allowing the mirror to float electrically. Mirrors that are tied to a voltage potential, which typically are grounded, are affected by a reset pulse and rotate away from their landed position. When the mirrors have rotated to the opposite side, a bias signal is applied to hold the repositioned mirror in place in the opposite state. Mirrors that electrically are floating do not experience the forces generated by the reset voltage and remain in their previous state. The preceding abstract is submitted with the understanding that it only will be used to assist in determining, from a cursory inspection, the nature and gist of the technical disclosure as described in 37 C.F.R. § 1.72(b). In no case should this abstract be used for interpreting the scope of any patent claims.

Claims

1. A method of operating a micromechanical device comprising:

providing a micromechanical device comprising at least one element comprising a member deflectable to a first state and a second state;

operating said device to place said at least one member in a state;

providing a signal to said element, said signal having a first condition to indicate said member should stay in its current state, and a second condition to indicate said member should transition from its current state;

providing a reset signal to said element such that said element provided said first condition stays in said current state, and said element provided said second condition transitions from said current state.

2. The method of claim 1, said providing a micromechanical device comprising providing a micromirror device.

3. The method of claim 1, said providing a micromechanical device comprising providing a micromirror array.

4. The method of claim 1, said providing a micromechanical device comprising providing an array of said elements, each said element comprising a pass transistor, a capacitor, and a deflectable member.

5. The method of claim 1, said operating step comprising driving an electrode to deflect said member.

6. The method of claim 1, said step of providing a reset signal comprising driving at least one electrode of said element.

7. The method of claim 1, said step of providing a reset signal comprising driving at least two electrodes of said element.

8. The method of claim 1, said step of providing a reset signal comprising driving at least one electrode on each side of an axis about which said member deflects.

9. A method of operating a micromechanical device comprising:

providing a micromechanical device comprising at least one element comprising a member deflectable to a first state and a second state;

operating said device to place said at least one member in a state;

providing a signal to said element, said signal having a first condition to indicate said member should stay in its current state regardless of said current state, and a second condition to indicate said member should transition from its current state regardless of said current state;

providing a reset signal to said element such that said element provided said first condition stays in said current state, and said element provided said second condition transitions from said current state.

10. The method of claim 9, said providing a micromechanical device comprising providing a micromirror device.

11. The method of claim 9, said providing a micromechanical device comprising providing an array of said elements, each said element comprising a pass transistor, a capacitor, and a deflectable member.

12. The method of claim 9, said operating step comprising driving an electrode to deflect said member.

13. The method of claim 9, said step of providing a reset signal comprising driving at least one electrode of said element.

14. The method of claim 9, said step of providing a reset signal comprising driving at least one electrode on each side of an axis about which said member deflects.

15. A method of operating a micromechanical device comprising:

providing a micromechanical device comprising at least one element comprising a member deflectable to a first state and a second state;

operating said device to place said at least one member in a state;

loading a memory cell associated with said micromechamcal element with a signal having a first condition to indicate said member should stay in its current state, and a second condition to indicate said member should transition from its current state;

providing a reset signal to said element such that said element provided said first condition stays in said current state, and said element provided said second condition transitions from said current state.

16. The method of claim 15, said providing a micromechanical device comprising providing a micromirror device.

17. The method of claim 15, said providing a micromechanical device comprising providing an array of said elements, each said element comprising a pass transistor, a capacitor, and a deflectable member.

18. The method of claim 15, said operating step comprising driving an electrode to deflect said member.

19. The method of claim 15, said step of providing a reset signal comprising driving at least one electrode of said element.

20. The method of claim 15, said step of providing a reset signal comprising driving at least one electrode on each side of an axis about which said member deflects.