Self-packaged optical interference display device having anti-stiction bumps, integral micro-lens, and reflection-absorbing layers

• US 20040217919A1
• Filed: 04/30/2003
• Published: 11/04/2004
• Est. Priority Date: 04/30/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Piehl, Arthur, Ghozeil, Adam L., Martin, Eric T., Przybyla, James R.
• Granted Patent: US 7,370,185 B2
• Time in Patent Office: Days
• US Class Current: 345/31
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 3/0008 Structures for avoiding electrostatic attraction, e.g. avoiding charge accumulation
• CPC Class Codes: G02B 1/11 Anti-reflection coatings
• 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 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

An electronic device of an embodiment of the invention is disclosed that at least partially displays a pixel of a display image. The device includes a first reflector and a second reflector defining an optical cavity therebetween that is selective of a visible wavelength at an intensity. The device includes a mechanism to allow optical properties of the cavity to be varied such that the visible wavelength and/or the intensity are variably selectable in correspondence with the pixel of the displayable image. The device also includes one or more transparent deposited films, one or more absorbing layers, an integral micro-lens, and/or one or more anti-stiction bumps. The deposited films are over one of the reflectors, for self-packaging of the device. The absorbing layers are over one of the reflectors, to reduce undesired reflections. The integral micro-lens is over one of the reflectors, and the anti-stiction bumps are between the reflectors.

Claims

1. An electronic device for at least partially displaying a pixel of a displayable image comprising:

a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variably selectable in correspondence with the pixel of the displayable image;

at least one of;

one or more transparent deposited films over one of the first and the second reflectors for self-packaging of the electronic device;

one or more absorbing layers over one of the first reflector and the second reflectors to reduce undesired reflections; and

,

an integral micro-lens over one of the first and the second reflectors;

one or more anti-stiction bumps between the first and the second reflectors.

2. The electronic device of claim 1, further comprising circuitry for controlling a voltage over the first reflector and the second reflector such that the voltage is dependent on a thickness of the optical cavity therebetween.

3. The electronic device of claim 2, wherein the circuitry comprises a voltage source and a capacitor in series with the first reflector and the second reflector.

4. The electronic device of claim 1, further comprising circuitry for controlling a predetermined amount of charge on the first reflector and the second reflector, the circuitry comprising a charge-sharing capacitor.

5. The electronic device of claim 4, wherein the circuitry comprises a voltage source and a second capacitor in parallel with the first reflector and the second reflector, the circuitry switching between the voltage source and the charge-sharing capacitor, and the second capacitor, the first reflector and the second reflector.

6. The electronic device of claim 1, further comprising a controlled current source and circuitry for controlling a time interval that the current source is applied to the first reflector and the second reflector.

7. The electronic device of claim 1, wherein the first reflector is a top, semi-reflective reflector, and the second reflector is a bottom, highly reflective reflector.

8. The electronic device of claim 1, wherein the mechanism allows a thickness of the optical cavity to be varied.

9. The electronic device of claim 1, wherein the mechanism permits one of the first and the second reflectors to move to allow a thickness of the optical cavity to be varied.

10. The electronic device of claim 1, wherein the mechanism comprises a flexure operatively coupled to one of the first and the second reflectors.

11. The electronic device of claim 1, wherein the optical cavity is analog, such that the both the visible wavelength and the intensity are variably selectable in correspondence with the pixel of the displayable image.

12. The electronic device of claim 1, wherein the optical cavity is digital, such that the visible wavelength of which the optical cavity is selective is fixed as a color component wavelength, and the intensity of the color component wavelength is variably selectable in correspondence with a corresponding color component of the pixel of the displayable image.

13. The electronic device of claim 1, wherein the optical cavity is one of reflectively selective and transmissively selective.

14. An electronic device for at least partially displaying a pixel of a displayable image comprising:

a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variable selectable in correspondence with the pixel of the displayable image; and

,

means for reducing undesired reflections on one of the first reflector and the second reflector.

15. The electronic device of claim 14, wherein the means comprises one or more absorbing layers.

16. An electronic device for at least partially displaying a pixel of a displayable image comprising:

a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variable selectable in correspondence with the pixel of the displayable image; and

,

means for self-packaging of the electronic device.

17. The electronic device of claim 16, wherein means comprises one or more transparent deposited films over one of the first reflector and the second reflector.

18. An electronic device for at least partially displaying a pixel of a displayable image comprising:

a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variable selectable in correspondence with the pixel of the displayable image; and

,

means for reducing stiction between the first and the second reflectors

19. The electronic device of claim 18, wherein the means comprises one or more anti-stiction bumps.

20. An electronic device for at least partially displaying a pixel of a displayable image comprising:

a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variable selectable in correspondence with the pixel of the displayable image; and

,

means for preventing reduced aperture ratio of one of the first and the second reflectors.

21. The electronic device of claim 20, wherein the means comprises an integral micro-lens over the one of the first and the second reflectors.

22. A display device comprising:

a plurality of electrically adjustable optical resonant cavities to correspondingly display a plurality of pixels of a displayable image by optical interference, each cavity comprising at least one of;

one or more transparent deposited films for self-packaging;

one or more absorbing layers to reduce undesired reflections; and

,

an integral micro-lens; and

,

one or more anti-stiction bumps to reduce stiction.

23. The display device of claim 22, wherein the plurality of cavities are analog, such that each cavity variably selects a visible wavelength at an intensity corresponding to a color and an intensity of a corresponding pixel of the displayable image.

24. The display device of claim 22, wherein the plurality of cavities correspondingly display the plurality of pixels of the displayable image by reflective optical interference.

25. The display device of claim 22, wherein the plurality of cavities correspondingly display the plurality of pixels of the displayable image by transmissive optical interference.

26. The display device of claim 22, wherein the plurality of cavities correspondingly display the plurality of pixels of the displayable image by optical interference of ambient light.

27. The display device of claim 22, wherein the plurality of cavities correspondingly display the plurality of pixels of the displayable image by optical interference of light including light provided by the display device.

28. A method for manufacturing an electronic device for at least partially displaying a pixel of a displayable image comprising:

providing a first reflector and a second reflector defining an optical cavity therebetween and selective of a visible wavelength at an intensity;

providing a mechanism to allow optical properties of the optical cavity to be varied such that at least one of the visible wavelength and the intensity are variably selectable in correspondence with the pixel of the displayable image; and

,

providing one or more transparent deposited films over one of the first and the second reflectors for self-packaging of the electronic device.

29. The method of claim 28, further comprising providing one or more absorbing layers over one of the first and the second reflectors to reduce undesired reflections.

30. The method of claim 28, further comprising providing an integral micro-lens over one of the first and the second reflectors.

31. The method of claim 28, further comprising providing one or more anti-stiction bumps between the first and the second reflectors.

32. A method for manufacturing a device for at least partially displaying a pixel of a displayable image comprising:

providing a bottom metal reflector layer on a substrate layer of the device;

depositing and patterning first filler material on the bottom metal reflector layer;

providing a flexure layer and a top metal reflector layer on the first filler material;

providing an oxide pixel plate layer on the flexure layer and the top metal reflector layer;

depositing and patterning second filler material on the oxide pixel plate layer;

depositing an oxide layer on the second filler material;

defining a via through the second filler material; and

,

removing the first filler material to define an optical cavity between the first and the top metal reflector layers, and the second filler material to define an air cavity between the oxide pixel plate layer and the oxide layer.

33. The method of claim 32, further comprising, after providing the bottom metal reflector layer, depositing an oxide dielectric layer.

34. The method of claim 32, wherein providing the bottom metal reflector layer comprises depositing and patterning the bottom metal reflector layer.

35. The method of claim 32, wherein providing the flexure layer and the top metal reflector layer comprises depositing the flexure layer, depositing the top metal reflector layer on the flexure layer, and patterning the flexure layer and the top metal reflector layer.

36. The method of claim 32, wherein providing the flexure layer and the top metal reflector layer comprises depositing the top metal reflector layer, depositing the flexure layer on the top metal reflector layer, and patterning the flexure layer and the top metal reflector layer.

37. The method of claim 32, wherein removing the first filler material and the second filler material comprises performing isotropic cleanout etching.

38. A display device constructed at least in part by performing a method comprising:

providing a bottom metal reflector layer on a silicon substrate layer of the display device;

depositing and patterning first filler material on the bottom metal reflector layer;

providing a flexure layer and a top metal reflector layer on the first filler material;

providing an oxide pixel plate layer on the flexure layer and the top metal reflector layer;

depositing and patterning second filler material on the oxide pixel plate layer;

depositing an oxide layer on the second filler material;

defining one or more vias through the second filler material; and

,

removing the first filler material to define individually controllable optical cavities between the first and the top metal reflector layers, and the second filler material to define air cavities between the oxide pixel plate layer and the oxide layer.

39. The display device of claim 38, further comprising, after providing the bottom metal reflector layer, depositing an oxide dielectric layer.

40. The display device of claim 38, further comprising providing a protective layer over the oxide layer.

41. The display device of claim 40, further comprising providing an anti-reflective coating over the protective layer.

42. The display device of claim 40, further comprising sputtering an absorbing layer over the protective layer.