Interferometric modulation of radiation

• US 7,692,844 B2
• Filed: 01/05/2004
• Issued: 04/06/2010
• Est. Priority Date: 05/05/1994
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Miles, Mark W.
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US10/752,140
• Publication Number:
  US 20040240032A1
• Time in Patent Office: 2,283 Days
• Field of Search: 359290-292, 359/295, 359/298, 359/223, 359/224, 359577-578
• US Class Current: 359/290
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/169 based on orientable non-spherical particles having a common optical characteristic, e.g. suspended particles of reflective metal flakes
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G06F 3/1446 display composed of modules, e.g. video walls
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0452 : Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 3/001 : using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2074 : using sub-pixels
• CPC Class Codes: G09G 3/2077 : by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/3466 : based on interferometric effect
• CPC Class Codes: G09G 5/02 : characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H01Q 9/26 : with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

Improvements in an interferometric modulator that has a cavity defined by two walls.

Claims

1. An interference modulator comprising:

a first wall;

a second wall separated from the first wall by a fluid-filled gap, the second wall configured to be movable such that it can be driven between a first state and a second state in a direction generally perpendicular to the first wall to change the volume of the gap, and further configured to form a contact position in the second state in which the first wall and the second wall are essentially adjacent to one another;

an optical interference cavity defined by the first wall and the second wall; and

an aperture in the movable second wall sized to allow fluid to flow into or out of the gap as the volume of the gap changes to control damping of the movable wall.

2. The modulator of claim 1 in which the aperture comprises a round hole in the center of the movable second wall.

3. The modulator of claim 1, additionally comprising stiction bumps positioned between the first and second walls, the stiction bumps configured to reduce the surface area over which the two walls touch in the contact position.

4. The modulator of claim 3, wherein the stiction bumps comprise electrodes.

5. The modulator of claim 1 wherein one of the two walls comprises a first mirror having a first reflectance and the other of the two walls comprises a second mirror having a second reflectance, the first reflectance being different from the second reflectance.

6. A method of manufacturing an optical interference modulator comprising:

providing a first wall; and

providing a second wall separated by the first wall by a fluid-filled gap, the second wall configured to be movable in a direction generally perpendicular to the first wall to a contact position in which the first wall and the second wall are essentially adjacent to one another and thereby changing the volume of the gap, wherein the second movable wall includes an aperture that is sized to allow fluid to flow into or out of the gap as the volume of the gap changes to control damping of the movable wall, and wherein the first and second walls define an optical interference cavity.

7. The method of claim 6, wherein the aperture comprises a round hole in the center of the second wall.

8. The method of claim 6, additionally comprising positioning stiction bumps between the first and second walls.

9. The method of claim 8, wherein the stiction bumps comprise electrodes.

10. The method of claim 6, wherein the first wall comprises a first mirror having a first reflectance and the second wall comprises a second mirror having a second reflectance, the first reflectance being different from the second reflectance.

11. The method of claim 6, additionally comprising packaging the modulator in a container, the ambient gas pressure inside the container optimized to control the damping effect of fluid moving into or out of the gap as the volume of the gap changes.

12. An interference modulator comprising:

means for interferometrically modulating light, wherein the modulating means comprises a first wall and a second wall separated from the first wall by an adjustable volume of fluid, the second wall configured to be movable in a direction generally perpendicular to the first wall to a position such that the first wall and the second wall are essentially adjacent to one another, thereby changing the volume of the gap; and

means for controlling damping of the second movable wall, wherein the controlling means comprises an aperture in the movable second wall sized to allow fluid into or out of the modulating means as the volume of the gap changes.

13. The modulator of claim 12 wherein the aperture is a round hole in the center of the movable second wall.

14. The modulator of claim 13, wherein the first wall comprises a first mirror having a first reflectance and the second wall comprises a second mirror having a second reflectance, the first reflectance being different from the second reflectance.

15. The modulator of claim 12 wherein the modulating means comprises an interference cavity defined by the first wall and the movable second wall.

16. The modulator of claim 12, additionally comprising stiction bumps positioned between the first and second walls.

17. The modulator of claim 16, wherein the stiction bumps comprise electrodes.