Method and device for multistate interferometric light modulation
View Patent ↗A multi-state light modulator comprises a first reflector. A first electrode is positioned at a distance from the first reflector. A second reflector is positioned between the first reflector and the first electrode. The second reflector is movable between an undriven position, a first driven position, and a second driven position, each having a corresponding distance from the first reflector. In one embodiment, the three positions correspond to reflecting white light, being non-reflective, and reflecting a selected color of light. Another embodiment is a method of making the light modulator. Another embodiment is a display including the light modulator.
1. A method of driving an electromechanical system comprising a first electrode, a second electrode, and a movable electrode positioned between the first electrode and the second electrode and configured to move to at least two positions therebetween, the method comprising:
applying a first voltage potential difference between the first electrode and the movable electrode so as to drive the movable electrode to a first position that is closer to the first electrode than the second electrode; and
applying a second voltage potential difference between the second electrode and the movable electrode so as to drive the movable electrode to a second position that is between the second electrode and the first position.
2. The method of claim 1 , wherein the second position is closer to the second electrode than the first electrode.
3. The method of claim 1 , wherein the second position is closer to the first electrode than the second electrode.
4. The method of claim 1 , wherein a first color is output when the movable electrode is in the first position.
5. The method of claim 4 , wherein a second color is output when the movable electrode is in the second position.
6. The method of claim 4 , wherein incident visible light is substantially absorbed when the movable electrode is in the second position.
7. The method of claim 1 , wherein light of a first wavelength is reflected from the electromechanical system when the movable electrode is in the first position.
8. The method of claim 7 , wherein light of a second wavelength is reflected from the electromechanical system when the movable electrode is in the second position.
9. The method of claim 7 , wherein incident light of visible wavelengths is substantially absorbed when the movable electrode is in the second position.
10. The method of claim 1 , further comprising applying a third voltage potential difference between the second electrode and the movable electrode so as to drive the movable electrode to a third position that is between the second position and the second electrode.
11. The method of claim 10 , wherein a first color is output when the movable electrode is in the first position.
12. The method of claim 11 , wherein incident visible light is substantially absorbed when the movable electrode is in the second position.
13. The method of claim 12 , wherein a second color is output when the movable electrode is in the third position.
14. An electromechanical system comprising:
a first electrode;
a second electrode; and
a movable electrode disposed between the first electrode and the second electrode, the movable electrode being configured to move between at least a first position that is disposed closer to the first electrode than the second electrode and a second position that is disposed between the first position and the second electrode,
wherein applying a first voltage potential difference between the first electrode and the movable electrode drives the movable electrode toward the first position and wherein applying a second voltage potential difference between the second electrode and the movable electrode drives the movable electrode toward the second position.
15. The system of claim 14 , wherein the first position comprises a position in contact with a dielectric layer.
16. The system of claim 14 , wherein the second position comprises a position in contact with a dielectric layer.
17. The system of claim 14 , wherein the second position is closer to the second electrode than the first electrode.
18. The system of claim 14 , wherein the second position is closer to the first electrode than the second electrode.
19. The system of claim 14 , wherein the first electrode is at least partially transparent.
20. The system of claim 19 , wherein the first electrode comprises at least one layer of reflective material.
21. The system of claim 14 , wherein the movable electrode comprises at least one layer of reflective material.
22. The system of claim 14 , wherein the system reflects white light when the movable electrode is in the first position.
23. The system of claim 22 , wherein the system reflects light in a range of visible wavelengths associated with a color when the movable electrode is in the second position.
24. The system of claim 22 , wherein the system substantially absorbs incident visible light when the movable electrode is in the second position.
25. The system of claim 14 , further comprising:
a processor that is configured to communicate with said electrode, said processor being configured to process image data; and
a memory device that is configured to communicate with said processor.
26. The system of claim 25 , further comprising a driver circuit configured to send at least one signal to the electrode.
27. The system of claim 26 , further comprising a controller configured to send at least a portion of the image data to the driver circuit.
28. The system of claim 25 , further comprising an image source module configured to send said image data to said processor.
29. The system of claim 28 , wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.
30. The system of claim 25 , further comprising an input device configured to receive input data and to communicate said input data to said processor.
31. A method of fabricating an electromechanical system, the method comprising:
forming a first electrode;
forming a second electrode disposed at a distance from the first electrode; and
forming a movable electrode disposed between the first electrode and the second electrode, the movable electrode being movable between at least a first position that is disposed closer to the first electrode than the second electrode and a second position that is disposed between the first position and the second electrode,
wherein the first electrode, second electrode, and movable electrode are formed such that applying a first voltage potential difference between the first electrode and the movable electrode drives the movable electrode toward the first position and such that applying a second voltage potential difference between the second electrode and the movable electrode drives the movable electrode toward the second position.
32. The method of claim 31 , wherein forming the first reflector comprises forming a layer of conductive material.
33. The method of claim 32 , wherein the layer of conductive material is at least partially transparent.
34. The method of claim 31 , wherein forming the movable reflector comprises forming a layer of conductive material.