Dielectric enhanced mirror for IMOD display

• US 9,057,872 B2
• Filed: 03/28/2011
• Issued: 06/16/2015
• Est. Priority Date: 08/31/2010
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Mignard, Marc Maurice, Khazeni, Kasra
• Primary Examiner(s): TRA, TUYEN Q
• Application Number:
  US13/073,829
• Publication Number:
  US 20120050299A1
• Time in Patent Office: 1,541 Days
• Field of Search: 359/290, 359/291, 359/292, 359/260, 359/315, 359/318, 359/224.1, 345/501, 356/454
• US Class Current: 1/1
• 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

Abstract

This disclosure provides systems, methods, and apparatus for display device including a dielectric stack positioned between a first electrically conductive layer and a second movable electrically conductive layer. In one aspect, the dielectric stack includes alternating dielectric layers of high and low indices of refraction. By controlling the refractive indices and thicknesses of layers within the dielectric stack, the display device'"'"'s states of light reflection may be reversed, such that light is reflected when the movable layer is positioned in proximity to the first electrically conductive layer.

Claims

1. A display device comprising:

a partially transparent and partially reflective layer;

a first dielectric layer having a first thickness and a first index of refraction characteristic;

a second dielectric layer having a second thickness and a second index of refraction characteristic, wherein an optical path length of the first dielectric layer through the first thickness is about the same as an optical path length of the second dielectric layer through the second thickness, and wherein the first index of refraction characteristic is greater than the second index of refraction characteristic;

a reflective layer, wherein the second dielectric layer is disposed between the reflective layer and the first dielectric layer; and

an optically resonant cavity defined between the partially transparent and partially reflective layer and the reflective layer.

2. The device of claim 1, wherein the first index of refraction characteristic is greater than 2.1.

3. The device of claim 2, wherein the first dielectric layer has an extinction coefficient characteristic that is less than 0.5.

4. The device of claim 3, wherein the first dielectric layer includes at least one of zirconium dioxide, titanium dioxide, gallium phosphide, silicon, gallium nitride, indium phosphide and hafnium oxide.

5. The device of claim 1, wherein the second index of refraction characteristic is less than 1.6.

6. The device of claim 5, wherein the second dielectric layer includes at least one of magnesium fluoride and silicon dioxide.

7. The device of claim 1, wherein the first thickness is between about 20 nm and about 100 nm.

8. The device of claim 1, wherein the second thickness is between about 20 nm and about 100 nm.

9. The device of claim 1, wherein the optical path length of the first dielectric layer through the first thickness is between (⅛

)*λ and

(⅜

)*λ

.

10. The device of claim 1, further comprising an air gap defined between the partially transparent and partially reflective layer and the first dielectric layer.

11. The device of claim 1, further comprising:

a display;

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 device of claim 11, further comprising:

a driving circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

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

14. The device of claim 11, further comprising an image source module configured to send the image data to the processor.

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

16. The device of claim 11, further comprising an input device configured to receive input data and to communicate the input data to the processor.

17. A display device comprising:

means for partially reflecting and partially transmitting light;

first dielectric means having a first thickness and a first index of refraction characteristic;

second dielectric means having a second thickness and a second index of refraction characteristic, wherein an optical path length of the first dielectric means through the first thickness is about the same as an optical path length of the second dielectric means through the second thickness, wherein the first index of refraction characteristic is greater than the second index of refraction characteristic, wherein the first dielectric means is disposed between the partially reflective and partially transmissive means and the second dielectric means;

means for reflecting light, wherein the second dielectric means is disposed between the reflective means and the first dielectric means; and

optically resonant means defined between the partially reflective and partially transmissive means and the reflective means.

18. The device of claim 17, wherein the first index of refraction characteristic is greater than 2.1.

19. The device of claim 17, wherein the second index of refraction characteristic is less than 1.6.

20. The device of claim 17, wherein the optical path length of the first dielectric means through the first thickness is between (⅛

)*λ and

(⅜

)*λ

.

21. A method of manufacturing a display device, the method comprising:

providing a substrate;

forming a partially reflective and partially transmissive layer on the substrate;

forming a sacrificial layer on the partially transparent and partially reflective layer;

forming a first dielectric layer on the sacrificial layer, the first dielectric layer having a first thickness and a first index of refraction characteristic;

forming a second dielectric layer on the first dielectric layer, the second dielectric layer having a second thickness and a second index of refraction characteristic, wherein an optical path length of the first dielectric layer through the first thickness is about the same as an optical path length of the second dielectric layer through the second thickness, wherein the first index of refraction characteristic is greater than the second index of refraction characteristic;

forming a reflective layer on the second dielectric layer; and

removing the sacrificial layer.

22. The method of claim 21, wherein the first index of refraction characteristic is greater than 2.1.

23. The method of claim 21, wherein the second index of refraction characteristic is less than 1.6.

24. The method of claim 21, wherein the optical path length of the first dielectric layer through the first thickness is between (⅛

)*λ and

(⅜

)*λ

.