Method of mitigating the effects of a defective electromechanical pixel

• US 5,289,172 A
• Filed: 10/23/1992
• Issued: 02/22/1994
• Est. Priority Date: 10/23/1992
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: McCormack, Brian C., Gale, Richard O. Jr.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): LOPEZ, FRANK D
• Application Number:
  US07/965,835
• Time in Patent Office: 487 Days
• Field of Search: 359/230, 359/290, 359/291, 359/292, 359/295, 358/62, 358/233, 340/764, 340/783, 340/805
• US Class Current: 345/108
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09F 9/372 the positions of the elements being controlled by the application of an electric field
• CPC Class Codes: G09G 2330/10 Dealing with defective pixels
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

Methods are disclosed by which the effects of a defective electromechanical pixel (20) having a beam (30) and a hinge (34,36) are mitigated. These methods may damage the hinge (34,36) or the beam (30) and comprise the step of applying a voltage sufficient to damage the hinge (34,36) or beam (30) of said electromechanical pixel (20) by mechanical overstress, thermal overstress, electrochemical reaction, or thermally induced chemical reaction. Other methods are also disclosed.

Claims

1. A method of mitigating the effects of a bright defective electromechanical pixel which transmits light into an observer'"'"'s field of view, the pixel having a beam and a hinge, comprising the step of applying a voltage sufficient to damage the electromechanical pixel in such a manner that the pixel no longer transmits said light into said field of view.

2. The method of claim 1 wherein said voltage is of a long duration.

3. The method of claim 1 wherein said voltage is of a high amplitude.

4. The method of claim 1 wherein said voltage is a set of periodic pulses.

5. The method of claim 1 wherein said damage is by mechanical overstress.

6. The method of claim 1 wherein said damage is by thermal overstress.

7. The method of claim 6 wherein said thermal overstress occurs in a vacuum.

8. The method of claim 6 wherein said thermal overstress occurs in a gas.

9. The method of claim 8 wherein said gas has a viscosity greater than air at one atmosphere of pressure.

10. The method of claim 1 wherein said damage is caused by a thermally induced chemical reaction.

11. The method of claim 10 wherein said thermally induced chemical reaction occurs in a gas.

12. The method of claim 1 wherein said damage is caused by an electrochemical reaction.

13. The method of claim 12 wherein said electrochemical reaction is a vapor phase electrochemical reaction.

14. The method of claim 1 wherein said damaged electromechanical pixel has a planar surface.

15. The method of claim 14 wherein said planar surface is parallel to an underlying substrate.

16. The method of claim 1 wherein said hinge is damaged.

17. The method of claim 1 wherein said beam is damaged.

18. The method of claim 1 wherein said defective pixel is part of an array of electromechanical pixels and further comprising the step of selectively addressing said defective pixel and applying said voltage only to said selectively addressed pixel.

19. The method of claim 1 wherein said defective pixel is part of an array of electromechanical pixels and further comprising the step of applying a voltage to a plurality of said electromechanical pixels sufficient to damage said defective pixel.

20. The method of claim 1 wherein said defective pixel is deflected and electrically non-responsive among an array of normally undeflected and electrically responsive electromechanical pixels and further comprising the steps of:

a) providing said array of pixels within an environment having a gas with a viscosity greater than air at one atmosphere of pressure; and

b) applying a periodic set of voltage pulses sufficient to damage said defective electromechanical pixel, yet insufficient to damage at least one of the undeflected, electrically responsive pixels.