ESD PROTECTION FOR MEMS DISPLAY PANELS

• US 20090040136A1
• Filed: 08/08/2007
• Published: 02/12/2009
• Est. Priority Date: 08/08/2007
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm, Inc.
• Inventors: Lan, Je-Hsiung, Zhou, Lixia
• Granted Patent: US 8,022,896 B2
• Time in Patent Office: Days
• US Class Current: 345/30
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection

Abstract

A MEMS (Microelectromechanical system) device is described. The device includes an array of MEMS elements with addressing lines and MEMS switches configured to selectively connect the addressing lines to a ground or other potential in the event of an over-voltage, such as during an ESD event. The arrangement is particularly advantageous for protecting the array, because the MEMS switches can be formed using substantially the same processing steps which are used to form the array.

Claims

1. A display device comprising:

a microelectromechanical system (MEMS) display portion comprising a plurality of MEMS display elements, each MEMS display element connected to at least one of a plurality of control inputs; and

a plurality of MEMS switches, each MEMS switch being configured to selectively connect at least one of the control inputs to a first potential in response to said control input reaching a second potential.

2. The device of claim 1, wherein the first potential is approximately equal to a ground potential.

3. The device of claim 1, wherein each MEMS switch is configured to selectively connect one or more of the MEMS display elements to the first potential through a resistor.

4. The device of claim 1, wherein each of the MEMS display elements is configured to actuate when a voltage with a magnitude higher than a first threshold is applied to the MEMS display element, wherein each of the MEMS switches is configured to actuate when a voltage with a magnitude higher than a second threshold is applied to the MEMS switch, and wherein the second threshold is higher than the first threshold.

5. The device of claim 1, wherein the MEMS display elements are formed in rows and columns, and the MEMS switches are formed as one or more additional rows or columns of MEMS switch elements adjacent to the MEMS display elements.

6. The device of claim 1, wherein each of the MEMS switches is configured to connect a component of the one or more of the MEMS display elements to ground when an electrostatic discharge (ESD) event occurs on the one or more control inputs.

7. The device of claim 1, wherein the MEMS switches each comprise first and second layers, wherein the first layer is configured to deform in response to a voltage across the first and second layers, and wherein the first and second layers are selectively connectable.

8. The device of claim 7, wherein the first and second layers are selectively electrically connected when the first layer is deformed.

9. The device of claim 8, each MEMS switch further comprising a dielectric layer between the first and second layers, the dielectric having one or more voids.

10. A display device comprising:

means for displaying an image, the displaying means comprising a plurality of display elements, each display element connected to at least one of a plurality of control inputs; and

a plurality of means for selectively connecting at least one of the control inputs to a first potential in response to said control input reaching a second potential.

11. The device of claim 10, wherein the first potential is approximately a ground potential.

12. The device of claim 10, wherein each connecting means is configured to selectively connect one or more of the MEMS display elements to the first potential through a resistor.

13. The device of claim 10, wherein each of the display elements is configured to actuate when a voltage with a magnitude higher than a first threshold is applied to the display element, wherein each of the connecting means is configured to connect one or more of the MEMS display elements to the first potential when a voltage with a magnitude higher than a second threshold is applied to the connecting means, and wherein the second threshold is higher than the first threshold.

14. The device of claim 10, wherein each of the connecting means is configured to connect a component of the one or more of the display elements to ground when an ESD event occurs on the one or more control inputs.

15. A method of connecting one or more row or column electrodes of an array to a first potential, the method comprising closing a MEMS switch in response to a voltage on the row or column electrode, wherein the row or column electrode is connected to the first potential, the voltage exceeding a threshold voltage.

16. The method of claim 15, wherein the voltage is generated as the result of an ESD event.

17. The method of claim 15, wherein the first potential is approximately at a ground potential.

18. The method of claim 15, wherein the MEMS switch is configured to sense the voltage.

19. The method of claim 15, further comprising opening the MEMS switch to disconnect the row or column electrode from the first potential.

20. A display device comprising:

a display comprising a plurality of MEMS display elements, each MEMS display element connected to one of a plurality of row electrodes and one of a plurality of column electrodes;

a plurality of MEMS switches, each MEMS switch connected to a first potential and to a row electrode or a column electrode, wherein each MEMS switch is configured to connect the first potential to the row or column electrode when a voltage on the row or column electrode exceeds a first threshold.

21. The device of claim 20, wherein the MEMS display elements are configured to actuate when an applied voltage exceeds a second threshold, the first threshold being greater than the second threshold.

22. A display device comprising:

a MEMS display portion comprising a plurality of MEMS display elements, each MEMS display element having a first actuation threshold;

a plurality of MEMS switches connected to the display portion, each MEMS switch having a second actuation threshold, wherein the second actuation threshold is higher than the first actuation threshold.

23. The device of claim 22, wherein the first potential is approximately equal to a ground potential.

24. The device of claim 22, wherein each MEMS switch is configured to selectively connect one or more of the MEMS display elements to the first potential through a resistor.

25. The device of claim 22, wherein the MEMS display elements are formed in rows and columns, and the MEMS switches are formed as one or more additional rows or columns of MEMS switch elements adjacent to the MEMS display elements.

26. The device of claim 22, wherein each of the MEMS switches is configured to connect a component of the one or more of the MEMS display elements to ground when an ESD event occurs on the one or more control inputs.

27. The device of claim 22, wherein the MEMS switches each comprise first and second layers, wherein the first layer is configured to deform in response to a voltage across the first and second layers, and wherein the first and second layers are selectively connectable.

28. The device of claim 27, wherein the first and second layers are selectively electrically connected when the first layer is deformed.

29. The device of claim 28, each MEMS switch further comprising a dielectric layer between the first and second layers, the dielectric having one or more voids.

30. A display device comprising:

means for displaying comprising a plurality of display elements, each display element having a first actuation threshold; and

means for selectively connecting the displaying means to one or more electrodes, the connecting means comprising a plurality of connecting elements, each connecting element having a second actuation threshold, wherein the second actuation threshold is higher than the first actuation threshold.

31. The device of claim 30, wherein the one or more electrodes are connected to an electrical potential approximately equal to a ground potential.

32. The device of claim 30, wherein each connecting element is configured to selectively connect one or more of the display elements to the one or more electrodes through a resistor.

33. The device of claim 30, wherein the display elements are formed in rows and columns, and the connecting elements are formed as one or more additional rows or columns of connecting elements adjacent to the display elements.

34. The device of claim 30, wherein each of the connecting elements is configured to connect a component of the plurality of the display elements to ground when an ESD event occurs on the device.

35. The device of claim 30, wherein the connecting elements each comprise first and second layers, wherein the first layer is configured to deform in response to a voltage across the first and second layers, and wherein the first and second layers are selectively connectable.

36. The device of claim 35, wherein the first and second layers are selectively electrically connected when the first layer is deformed.

37. The device of claim 36, each connecting element further comprising a dielectric layer between the first and second layers, the dielectric having one or more voids.