PERIODIC DIMPLE ARRAY

• US 20090073539A1
• Filed: 12/03/2007
• Published: 03/19/2009
• Est. Priority Date: 09/14/2007
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm, Inc.
• Inventors: Mignard, Marc Maurice
• Granted Patent: US 7,773,286 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/0019 Flexible or deformable structures not provided for in groups B81C1/00142 - B81C1/00182
• 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: G02B 26/0825 the reflecting element being a flexible sheet or membrane, e.g. for varying the focus flexible mirrors for cosmetic use A45D42/24
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A microelectromechanical (MEMS) device includes a substrate, an actuation electrode over the substrate, a reflective layer over the actuation electrode, and a support layer between the actuation electrode and the reflective layer. The reflective layer includes at least one aperture through the reflective layer. The support layer includes a recess between the actuation electrode and the at least one aperture. Upon application of a control signal to the device, at least a first portion of the reflective layer is configured to move into the recess and at least a second portion of the reflective layer is configured to remain stationary. The reflectivity of the MEMS device is dominantly modulated by changing a phase difference between light reflected from the first portion and light reflected from the second portion.

Claims

1. A microelectromechanical (MEMS) device comprising:

a substrate;

an actuation electrode over the substrate;

a reflective layer over the actuation electrode, the reflective layer including at least one aperture through the reflective layer; and

a support layer between the actuation electrode and the reflective layer, the support layer including a recess between the actuation electrode and the at least one aperture, wherein upon application of a control signal to the device, at least a first portion of the reflective layer is configured to move into the recess and at least a second portion of the reflective layer is configured to remain stationary, wherein the reflectivity of the MEMS device is dominantly modulated by changing a phase difference between light reflected from the first portion and light reflected from the second portion.

2. The MEMS device of claim 1, wherein the control signal comprises a voltage difference between the actuation electrode and the reflective layer.

3. The MEMS device of claim 1, wherein a ratio of an area of the first portion to an area of the second portion is about 1:

1.

4. The MEMS device of claim 1, wherein the reflective layer includes a plurality of apertures through the reflective layer and wherein the support layer includes a recess below each of the plurality of apertures, wherein upon application of the control, the first portion of the reflective layer is configured to move into the recesses and the second portion of the reflective layer is configured to remain stationary.

5. The MEMS device of claim 4, wherein the recesses are in a pattern that is periodic in two dimensions along the support layer.

6. The MEMS device of claim 5, wherein adjacent said recesses have a center-to-center distance less than about 2 μ

m.

7. The MEMS device of claim 4, wherein adjacent said recesses have an edge-to-edge distance less than about 1 μ

m.

8. The MEMS device of claim 4, wherein the reflective layer comprises a plurality of generally parallel portions extending along a first direction across the device and wherein the actuation electrode comprises a plurality of generally parallel portions extending along a second direction across the device, the first direction substantially non-parallel to the second direction, wherein areas of overlap between the generally parallel portions of the reflective layer and the generally parallel portions of the actuation electrode comprise pixels.

9. The MEMS device of claim 8, wherein the generally parallel portions of the reflective layer comprise stripes and wherein the generally parallel portions of the actuation electrode comprise stripes.

10. The MEMS device of claim 8, wherein the first direction is substantially perpendicular to the second direction.

11. The MEMS device of claim 8, wherein the support layer has a first thickness under a first said generally parallel portion of the reflective layer, a second thickness under a second said generally parallel portion of the reflective layer, and a third thickness under a third said generally parallel portion of the reflective layer, wherein the first, second, and third thicknesses are different from each other.

12. The MEMS device of claim 11, wherein a difference in thickness between the first thickness and the second thickness is greater than a thickness of the first generally parallel portion of the reflective layer and wherein a difference in thickness between the second thickness and the third thickness is greater than a thickness of the second generally parallel portion of the reflective layer.

13. The MEMS device of claim 1, wherein a width of the at least one aperture in the reflective layer is between about 10 and 300 nm n.

14. The MEMS device of claim 1, wherein a width of the recess in the support layer is less than about 1 μ

m.

15. The MEMS device of claim 1, wherein a ratio of a width of the at least one aperture in the reflective layer to a width of the recess in the support layer is less than about 1:

3.

16. The MEMS device of claim 1, wherein the support layer has a thickness between about 100 and 150 mm.

17. The MEMS device of claim 1, wherein the recess is at least partially bounded by a substantially flat surface.

18. The MEMS device of claim 1, wherein the reflectivity of the MEMS device is changeable between a zero phase difference and a non-zero phase difference.

19. The MEMS device of claim 1, wherein the substrate is at least partially transparent, wherein the actuation electrode is at least partially transparent, and wherein the support layer is at least partially transparent.

20. The MEMS device of claim 1, wherein the MEMS device is operably viewable through the actuation electrode and from a side of the reflective layer opposite the actuation electrode.

21. The MEMS device of claim 1, wherein the support layer comprises photoresist.

22. The MEMS device of claim 1, wherein the substrate comprises metal.

23. The MEMS device of claim 1, wherein the recess extends through the support layer.

24. The MEMS device of claim 1, further comprising an electrically insulating layer between the actuation electrode and the support layer.

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

a display;

a processor that is configured to communicate with the display, the processor configured to process image data; and

a memory device configured to communicate with the processor.

26. The MEMS device of claim 25, further comprising a driver circuit configured to send at least one signal to the display.

27. The MEMS device of claim 26, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

28. The MEMS device of claim 25, further comprising an image source module configured to send said image data to said processor.

29. The MEMS device of claim 28, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

30. The MEMS device of claim 25, further comprising an input device configured to receive input data and to communicate said input data to said processor.

31. A microelectromechanical (MEMS) device comprising:

means for applying a control signal;

means for supporting the control signal applying means, the control signal applying means over the means for supporting the control signal applying means;

means for modulating light; and

means for supporting the light modulating means, the light modulating means over the means for supporting the control signal applying means, the means for supporting the light modulating means between the control signal applying means and the light modulating means, the light modulating means including means for conducting a fluid through the light modulating means, the means for supporting the light modulating means including a recess between the control signal applying means and the fluid conducting means, wherein upon application of a control signal to the device, at least a first portion of the light modulating means is configured to move into the recess and at least a second portion of the light modulating means is configured to remain stationary, wherein the reflectivity of the MEMS device is dominantly modulated by changing a phase difference between light reflected from the first portion and light reflected from the second portion.

32. The MEMS device of claim 31, wherein the control signal applying means comprises an actuation electrode.

33. The MEMS device of claim 31, wherein the means for supporting the control signal applying means comprises a substrate.

34. The MEMS device of claim 31, wherein the light modulating means comprises a reflective layer.

35. The MEMS device of claim 31, wherein the means for supporting the light modulating means comprises a support layer.

36. The MEMS device of claim 31, wherein the fluid conducting means comprises an aperture through the means for modulating light.

37. A method of manufacturing a microelectromechanical (MEMS) device, the method comprising:

forming an actuation electrode over a substrate;

forming a support layer over the actuation electrode;

forming a reflective layer over the support layer;

forming at least one aperture through the reflective layer; and

removing a first portion of the support layer between the actuation electrode and the at least one aperture while a second portion of the support layer remains, the second portion supporting the reflective layer, a width of the first portion larger than a width of the at least one aperture, wherein after removal the reflectivity of the MEMS device is dominantly modulated by changing a phase difference between light reflected from the first portion and light reflected from the second portion.

38. The method of claim 37, wherein forming the at least one aperture comprises milling the reflective layer with a focused ion beam (FIB).

39. The method of claim 37, wherein removing the portion of the support layer comprises etching the support layer through the at least one aperture.

40-52. -52. (canceled)