Interferometric modulator with internal polarization and drive method

• US 7,460,292 B2
• Filed: 06/03/2005
• Issued: 12/02/2008
• Est. Priority Date: 06/03/2005
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chou, Chen-Jean
• Primary Examiner(s): MARTINEZ, JOSEPH P
• Application Number:
  US11/145,416
• Publication Number:
  US 20060274398A1
• Time in Patent Office: 1,278 Days
• Field of Search: 359/223, 359/224, 359/247, 359/290, 359/291, 359/568, 359/627, 359/846, 359/847, 348/772
• US Class Current: 359/291
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• 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

Abstract

A method of creating an internal dipole moment in an interferometric light modulating device is disclosed. In certain embodiments, the method includes applying heat and an electrical field to a dielectric layer of an interferometric light modulating device. Before this method, the dielectric layer has mobile charges or includes random dipoles. After this method, however, those random dipoles are substantially aligned, thereby inducing a fixed dipole moment in the dielectric layer. The electric field creates the dipole moment in the dielectric layer and the heat helps increase the speed of the process by supplying additional activation energy. Having a dielectric layer with an induced dipole moment provides an internal voltage source that provides at least a portion of the voltage required to operate the interferometric light modulating device. The induced dipole moment also reduces the possibility of an uncontrolled shift of charge within the device during operation.

Claims

1. A microelectromechanical systems (MEMS) device, comprising:

a first electrode;

a second electrode substantially reflective of light;

a first layer located between the first and second electrodes, the first layer comprising a non-zero dipole moment when no voltage is applied across the first and second electrodes; and

a second layer at least partially reflective of light, the second electrode in operable proximity to the second layer, wherein the second electrode is movable with respect to the second layer upon application of a voltage across the first and second electrodes.

2. The MEMS device of claim 1, wherein the first layer comprises a dielectric material.

3. The MEMS device of claim 1, wherein the first layer comprises a ferroelectric material.

4. The MEMS device of claim 1, wherein the first layer comprises SiO_x, wherein x is less than 2.

5. The MEMS device of claim 1, wherein the first layer comprises silicon nitride.

6. The MEMS device of claim 1, wherein the first layer comprises a material selected from a group consisting of:

silicon oxide, silicon nitride, nitrided SiO₂, titanium oxide, semi-insulating polycrystalline silicon, and oxy-nitride.

7. The MEMS device of claim 1, wherein the second layer comprises the first electrode.

8. The MEMS device of claim 7, wherein the first layer is sputtered over the second layer.

9. The MEMS device of claim 1, further comprising:

a display;

a processor that is in electrical communication with said display, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

10. The MEMS device of claim 9, further comprising:

a first controller configured to send at least one signal to said display; and

a second controller configured to send at least a portion of said image data to said first controller.

11. The MEMS device of claim 9, further comprising an image source module configured to send said image data to said processor.

12. The MEMS device of claim 11, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

13. The MEMS device of claim 9, further comprising an input device configured to receive input data and to communicate said input data to said processor.

14. A microelectromechanical systems (MEMS) device, comprising:

means for at least partially reflecting light;

means for substantially reflecting light, the substantially reflecting means in operable proximity to the at least partially reflecting means;

first means for conducting electrical signals;

second means for conducting electrical signals, wherein the substantially reflecting means is movable with respect to the at least partially reflecting means upon application of a voltage across the first conducting means and the second conducting means; and

means for providing a non-zero dipole moment between the first conducting means and the second conducting means when no voltage is applied across the first conducting means and the second conducting means.

15. The MEMS device of claim 14, wherein the first conducting means comprises an electrode.

16. The MEMS device of claim 14, wherein the second conducting means comprises an electrode.

17. The MEMS device of claim 14, wherein the providing means comprises a dielectric layer.

18. The MEMS device of claim 14, wherein the providing means comprises a layer of SiO_x, wherein x is less than 2.

19. The MEMS device of claim 14, wherein the providing means comprises a layer of silicon nitride.

20. The MEMS device of claim 14, wherein the providing means comprises a material selected from a group consisting of:

silicon oxide, silicon nitride, nitrided SiO₂, titanium oxide, semi-insulating polycrystalline silicon, and oxy-nitride.

21. The MEMS device of claim 14, wherein the at least partially reflecting means comprises the first conducting means.

22. The MEMS device of claim 14, wherein the at least partially reflecting means comprises a layer of indium tin oxide (ITO).

23. The MEMS device of claim 14, wherein the substantially reflecting means comprises a layer of aluminum.

24. A micro electromechanical systems (MEMS) device, comprising:

a first electrode;

a second electrode substantially reflective of light;

a first layer located between the first and second electrodes, the first layer configured to maintain a non-zero dipole moment during operation; and

a second layer at least partially reflective of light, the second electrode in operable proximity to the second layer, wherein the second electrode is movable with respect to the second layer upon actuation of a voltage across the first and second electrodes.

25. The MEMS device of claim 24, wherein the operation comprises actuation.

26. The MEMS device of claim 24, wherein the operation comprises relaxation.

27. The MEMS device of claim 24, wherein the first layer comprises a dielectric material.

28. The MEMS device of claim 24, wherein the first layer comprises a ferroelectric material.

29. The MEMS device of claim 24, wherein the first layer comprises SiO_x, wherein x is less than 2.

30. The MEMS device of claim 24, wherein the first layer comprises silicon nitride.

31. The MEMS device of claim 24, wherein the first layer comprises material selected from a group consisting of:

silicon oxide, silicon nitride, nitrided SiO₂, titanium oxide, semi-insulating polycrystalline silicon, and oxy-nitride.

32. The MEMS device of claim 24, wherein the second layer comprises the first electrode.

33. The MEMS device of claim 24, wherein the first layer is sputtered over the second layer.