SYSTEM AND METHOD FOR MULTI-LEVEL BRIGHTNESS IN INTERFEROMETRIC MODULATION

• US 20090135465A1
• Filed: 12/23/2008
• Published: 05/28/2009
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Chui, Clarence
• Granted Patent: US 7,787,173 B2
• Time in Patent Office: Days
• US Class Current: 359/295
• 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 2300/0439 Pixel structures
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/207 by domain size control G09G3/3637 takes precedence
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A display having a plurality of reflective display elements. In one embodiment, the display elements comprise at least one electrode having a plurality of active areas. In one embodiment, at least two of the sizes of the active areas are different with respect to each other, e.g., they are non-uniform in size. The interferometric modulators have a plurality of states, wherein selected ones of the interferometric modulators are configured to be actuated depending differing electrostatic forces in the interferometric modulators. The electrostatic forces in the interferometric modulators are different at least in part due to variations in the sizes of the active areas of the electrodes.

Claims

1. A display device, comprising:

a plurality of interferometric modulators which interferometrically modulate light, the plurality of interferometric modulators comprising;

a first electrode having a substantially non-uniform width;

a plurality of second electrodes separated from the first electrode, wherein at least two of the second electrodes overlap areas of the first electrode such that each of the overlapped areas have different sizes; and

a plurality of movable reflective layers,

wherein the plurality of movable reflective layers can be selectively moved by varying electrostatic forces between the first electrode and selected ones of the plurality of second electrodes.

2. The display device of claim 1, further comprising a driver circuit configured to vary voltage potential differences between the first and selected ones of the plurality of second electrodes to create the electrostatic forces.

3. The display device of claim 2, wherein the driver circuit is further configured to provide a common voltage level to the second electrodes that overlap the different sized areas of the first electrode.

4. The display device of claim 2, wherein the driver circuit is further configured to provide discrete voltage levels to each of the second electrodes that overlap the different sized areas of the first electrode.

5. The display device of claim 1, wherein the first electrode comprises one or more non-linear edges forming the substantially non-uniform width.

6. The display device of claim 1, wherein the plurality of reflective layers is coupled to the first electrode.

7. The display element of claim 1, wherein each of the plurality of reflective layers is coupled to at least one of the plurality of second electrodes.

8. The display device of claim 1, wherein the at least two of the plurality of second electrodes that overlap different sized areas of the first electrode comprise a pixel.

9. The display device of claim 1, wherein the brightness of the display device as viewed from a viewing direction is varied based on the selective movement of the plurality of movable reflective layers.

10. A display array comprising a plurality of the display devices of claim 1.

11. A method comprising:

providing a first electrode having a substantially non-uniform width;

providing a plurality of reflective display elements which interferometrically modulate light, each of the plurality of reflective display elements comprising a movable reflective layer and a second electrode; and

applying a voltage difference between the first electrode and selected ones of the plurality of second electrode to actuate selected ones of the plurality of reflective display elements.

12. The method of claim 11, wherein the brightness of light as seen from a viewing perspective of the display elements varies in response to the selective actuation of the plurality of reflective display elements.

13. The method of claim 11, wherein the first electrode comprises one or more non-linear edges forming the substantially non-uniform width.

14. The method of claim 11, wherein interferometrically modulating light comprises at least partially reflecting incident light with the movable reflective layer, wherein the movable reflective layer is coupled to one of the electrodes.

15. A display device, comprising:

a plurality of means for interferometrically modulating light, the plurality of interferometrically light modulating means comprising;

a first means for conducting electricity, the first conducting means having a substantially non-uniform width;

a plurality of second means for conducting electricity, the plurality of second conducting means separated from the first conducting means, wherein at least two of the second conducting means overlap areas of the first conducting means such that each of the overlapped areas have different sizes; and

a plurality of movable means for reflecting light,

wherein the plurality of movable light reflecting means can be selectively moved by varying electrostatic forces between the first conducting means and selected ones of the plurality of second conducting means.

16. The display device of claim 15, wherein the plurality of interferometrically light modulating means comprises interferometric modulators, the first conducting means comprises a first electrode, the second conducting means comprises a second electrode and the light reflecting means comprises a reflective layer.

17. The display device of claim 15, further comprising means for providing a variable voltage difference between the first conducting means and selected ones of the plurality of the second conducting means.

18. A display device, comprising:

at least one array of interferometric modulators which interferometrically modulate light, the at least one array of interferometric modulators comprising a first electrode having a substantially non-uniform width,

each of the interferometric modulators further comprising a movable reflective layer and a second electrode separated from the first electrode and overlapping with a portion of the first electrode,

wherein at least one of the interferometric modulators is configured to be actuated by varying electrostatic forces between the first electrode and the second electrode of the at least one interferometric modulator.

19. The display device of claim 18, wherein the first electrode has a plurality of active areas of different sizes.

20. The display device of claim 18, wherein the first electrode has a substantially staircase shape from a viewing perspective of the display device.

21. The display device of claim 18, wherein the first electrode has a pyramidal shape from a viewing perspective of the display device.

22. The display device of claim 18, additionally comprising a latch electrode for modifying an activation voltage threshold of at least one of the interferometric modulators.

23. The display device of claim 22, wherein the latch electrode is placed proximate to an end of an active area of the interferometric modulators.

24. The display device of claim 18, wherein the first electrode comprises one or more curved edges.

25. The display element of claim 18, wherein the movable reflective layer is coupled to the first electrode.

26. The display element of claim 18, wherein the movable reflective layer is coupled to the second electrode.