Interferometric modulator with dielectric layer

• US 8,437,070 B2
• Filed: 10/11/2011
• Issued: 05/07/2013
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Cummings, William J.
• Primary Examiner(s): CHOI, WILLIAM C
• Application Number:
  US13/270,759
• Publication Number:
  US 20120026176A1
• Time in Patent Office: 574 Days
• Field of Search: 359/238, 359/247, 359/290, 359/302
• US Class Current: 359/290
• 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: Y02D 30/70 in wireless communication networks

Abstract

By selectively placing color filters with different transmittance spectrums on an array of modulator elements each having the same reflectance spectrum, a resultant reflectance spectrum for each modulator element and it'"'"'s respective color filter is created. In one embodiment, the modulator elements in an array are manufactured by the same process so that each modulator element has a reflectance spectrum that includes multiple reflectivity lines. Color filters corresponding to multiple colors, such as red, green, and blue, for example, may be selectively associated with these modulator elements in order to filter out a desired wavelength range for each modulator element and provide a multiple color array. Because the modulator elements are manufactured by the same process, each of the modulator elements is substantially the same and common voltage levels may be used to activate and deactivate selected modulation.

Claims

1. An interferometric modulator comprising:

a partially reflective surface;

a reflective surface, wherein at least one of the partially reflective surface and the reflective surface is movable with respect to the other to provide open and closed states; and

a dielectric layer between the partially reflective surface and the reflective surface, wherein the dielectric layer has a thickness configured to cause the interferometric modulator to produce a reflectance spectrum that includes a tail of second-order blue light when in the closed state.

2. The interferometric modulator of claim 1, wherein the dielectric layer has a thickness of at least about 700 Angstroms.

3. The interferometric modulator of claim 1, wherein the dielectric layer has a thickness in the range of about 2200 to 2500 Angstroms.

4. The interferometric modulator of claim 1, wherein the dielectric layer includes an oxide film.

5. The interferometric modulator of claim 1, wherein the closed state produces a dark state and the open state produces a bright state.

6. The interferometric modulator of claim 1, further comprising a filter structure configured to attenuate the tail of the second-order blue light.

7. The interferometric modulator of claim 1, wherein the reflectance spectrum further includes a tail of first-order red light.

8. The interferometric modulator of claim 7, further comprising a filter structure configured to attenuate the tail of the first-order red light and the tail of the second-order blue light to darken the dark state of the interferometric modulator.

9. The interferometric modulator of claim 1, wherein the partially reflective surface is fixed and the reflective surface is movable.

10. An apparatus comprising a display including a plurality of interferometric modulators according to claim 1.

11. The apparatus of claim 10, further comprising:

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

a memory device that is configured to communicate with the processor.

12. The apparatus as recited in claim 11, further comprising a driver circuit configured to send at least one signal to the display.

13. The apparatus as recited in claim 12, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

14. The apparatus as recited in claim 11, further comprising an image source module configured to send the image data to the processor.

15. The apparatus as recited in claim 14, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.

16. The apparatus as recited in claim 11, further comprising an input device configured to receive input data and to communicate the input data to the processor.

17. An interferometric modulator comprising:

a partially reflective surface;

a reflective surface, wherein at least one of the partially reflective surface and the reflective surface is movable with respect to the other to provide open and closed states; and

means for electrically insulating disposed between the partially reflective surface and the reflective surface, wherein the electrically insulating means has a thickness configured to cause the interferometric modulator to produce a reflectance spectrum that includes a tail of second-order blue light when in the closed state.

18. The interferometric modulator of claim 17, wherein the electrically insulating means includes a dielectric layer.

19. The interferometric modulator of claim 17, wherein the electrically insulating means has a thickness of at least about 700 Angstroms.

20. The interferometric modulator of claim 17, wherein the electrically insulating means has a thickness in the range of about 2200 to 2500 Angstroms.

21. The interferometric modulator of claim 17, wherein the electrically insulating means includes an oxide film.

22. A method of manufacturing an interferometric modulator, the method comprising:

fabricating a partially reflective surface;

fabricating a reflective surface, wherein at least one of the partially reflective surface and the reflective surface is movable with respect to the other to provide open and closed states; and

positioning a dielectric layer between the partially reflective surface and the reflective surface, wherein the dielectric layer has a thickness configured to cause the interferometric modulator to produce a reflectance spectrum that includes a tail of second-order blue light when in the closed state.

23. The method of claim 22, wherein the dielectric layer has a thickness of at least about 700 Angstroms.

24. The method of claim 22, wherein the dielectric layer has a thickness in the range of about 2200 to 2500 Angstroms.

25. The method of claim 22, wherein the dielectric layer includes an oxide film.

26. A method of operating a display, the method comprising:

receiving light from a light source so that the light at least partially passes through a partially reflective surface and reflects from a reflective surface, wherein an optical cavity is formed between the partially reflective surface and the reflective surface; and

actuating at least one of the partially reflective surface and the reflective surface to a closed state, wherein a dielectric layer is positioned between the partially reflective surface and the reflective surface, the dielectric layer having a thickness configured to cause the closed state to produce a reflectance spectrum that includes a tail of second-order blue light.

27. The method of claim 26, wherein the dielectric layer has a thickness of at least about 700 Angstroms.

28. The method of claim 26, wherein the dielectric layer has a thickness in the range of about 2200 to 2500 Angstroms.

29. The method of claim 26, further comprising attenuating the tail of the second-order blue light.