Hybrid color synthesis for multistate reflective modulator displays

• US 7,403,180 B1
• Filed: 01/29/2007
• Issued: 07/22/2008
• Est. Priority Date: 01/29/2007
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Xu, Gang, Silverstein, Louis D., Lewis, Alan G., Gille, Jennifer Lee
• Primary Examiner(s): Sanghavi; Hemang
• Application Number:
  US11/699,542
• Publication Number:
  US 20080180784A1
• Time in Patent Office: 540 Days
• Field of Search: 385/24, 385146-147, 359/290, 359/291, 345/55, 345/84, 345/85
• US Class Current: 345/84
• 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 5/201 in the form of arrays
• 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 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A display device including a plurality of optical modulators and a plurality of filter elements on a reflective side of the plurality of optical modulators is provided. The plurality of optical modulators includes a first set of optical modulators and a second set of optical modulators. Each optical modulator of the plurality of optical modulators is configured to be selectively switched among at least a first state, a second state, and a third state. Each state has a different spectral reflectance. The plurality of filter elements includes a first set of filter elements corresponding to the first set of optical modulators and a second set of filter elements corresponding to the second set of optical modulators. The first set of filter elements has a different spectral transmittance than the second set of filter elements.

Claims

1. A display device comprising:

a plurality of optical modulators comprising a first set of optical modulators and a second set of optical modulators, each optical modulator of the plurality of optical modulators configured to be selectively switched among at least a first state, a second state, and a third state, each state having a different spectral reflectance; and

a plurality of filter elements on a reflective side of the plurality of optical modulators, the plurality of filter elements comprising a first set of filter elements corresponding to the first set of optical modulators and a second set of filter elements corresponding to the second set of optical modulators, the first set of filter elements having a different spectral transmittance than the second set of filter elements.

2. The display device of claim 1, wherein the size and shape of each filter element corresponds to the size and shape of a corresponding optical modulator.

3. The display device of claim 1, wherein the plurality of filter elements forms a checkerboard pattern in which the first set of filter elements alternate with the second set of filter elements in two substantially perpendicular directions.

4. The display device of claim 1, wherein the plurality of filter elements forms a striped pattern in which the first set of filter elements alternate with the second set of filter elements in one direction.

5. The display device of claim 1, wherein a spectral reflectance configuration of the first set of optical modulators is the same as a spectral reflectance configuration of the second set of optical modulators.

6. The display device of claim 1, wherein at least one of the first, second, and third states of the first set of optical modulators has a different spectral reflectance than the first, second, and third states of the second set of optical modulators.

7. The display device of claim 1, wherein the device is configured to produce a color image.

8. The display device of claim 1, wherein the device is configured to produce three primary colors suitable for rendering color images.

9. The display device of claim 1, wherein the first set of filter elements has a spectral transmittance of magenta and the second set of filter elements has a spectral transmittance of cyan.

10. The display device of claim 1, wherein the spectral reflectance of the first state is substantially yellow, the spectral reflectance of the second state is substantially blue, and the spectral reflectance of the third state is substantially black.

11. The display device of claim 1, wherein the first set of filter elements has a spectral transmittance of magenta and the second set of filter elements has a spectral transmittance of green.

12. The display device of claim 11, wherein the first set of filter elements has an area less than an area of the second set of filter elements.

13. The display device of claim 12, wherein the area of the first set of filter elements is between about 50% to 75% less than the area of the second set of filter elements.

14. The display device of claim 1, wherein the spectral reflectance of the first state is substantially yellow, the spectral reflectance of the second state is substantially cyan, and the spectral reflectance of the third state is substantially black.

15. The display device of claim 1, wherein the spectral reflectance of the first state is substantially white, the spectral reflectance of the second state is substantially a narrowband color, and the spectral reflectance of the third state is substantially black.

16. The display device of claim 1, further comprising a light source.

17. The display device of claim 16, wherein the light source comprises a broadband light source.

18. The display device of claim 16, wherein the light source comprises a plurality of narrow band light sources.

19. The display device of claim 1, wherein the plurality of optical modulators are configured to reflect ambient light.

20. A display device comprising:

first means for optically modulating light between at least a first color, a second color, and a third color;

second means for optically modulating light between the first color, the second color, and the third color;

first means for filtering light modulated by the first modulating means; and

second means for filtering light modulated by the second modulating means, wherein the first filtering means has a different spectral transmittance than the second filtering means.

21. The display device of claim 20, wherein the first and second modulating means comprise a plurality of optical modulators, each optical modulator of the plurality of optical modulators configured to be selectively switched to modulate light between the first, second, and third colors.

22. The display device of claim 20, wherein the first filtering means comprises a first set of filter elements corresponding to the first modulating means and the second filtering means comprises a second set of filter elements corresponding to the second modulating means.

23. A method of generating an image, the method comprising:

providing a display device comprising a plurality of optical modulators comprising a first set of optical modulators and a second set of optical modulators, each optical modulator of the plurality of optical modulators configured to be selectively switched among at least a first state, a second state, and a third state, each state having a different spectral reflectance, and a filter on a reflective side of the plurality of optical modulators, the filter comprising a first set of filter elements corresponding to the first set of optical modulators and a second set of filter elements corresponding to the second set of optical modulators, the first set of filter elements having a different spectral transmittance than the second set of filter elements;

directing light from a light source onto the display device; and

selectively switching the plurality of optical modulators between the states.

24. The method of claim 23, wherein the first set of filter elements has a transmission spectrum of magenta and the second set of filter elements has a transmission spectrum of cyan, and wherein the first state has a spectral reflectance of yellow, the second state has a spectral reflectance of blue, and the third state has a spectral reflectance of black.

25. The method of claim 23, wherein the first set of filter elements has a transmission spectrum of magenta and the second set of filter elements has a transmission spectrum of green, and wherein the first state has a spectral reflectance of yellow, the second state has a spectral reflectance of cyan, and the third state has a spectral reflectance of black.

26. The method of claim 23, wherein directing the light comprises directing light from a broadband light source.

27. The method of claim 23, wherein directing the light comprises directing light from a plurality of narrow band light sources.

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

forming a plurality of optical modulators comprising a first set of optical modulators and a second set of optical modulators, each optical modulator of the plurality of optical modulators configured to be selectively switched among at least a first state, a second state, and a third state, each state having a different spectral reflectance; and

forming a plurality of filter elements on a reflective side of the plurality of optical modulators, the plurality of filter elements comprising a first set of filter elements corresponding to the first set of optical modulators and a second set of filter elements corresponding to the second set of optical modulators, the first set of filter elements having a different spectral transmittance than the second set of filter elements.

29. The method of claim 28, wherein forming the first set of optical modulators comprises a first set of process steps and forming the second set of optical modulators comprises a second set of process steps, the second set of steps comprising the first set of steps.

30. The method of claim 28, wherein forming the plurality of optical modulators comprises depositing a first sacrificial layer having a first thickness and a second sacrificial layer having a second thickness, and wherein the thicknesses of the first and second sacrificial layers determine the spectral reflectance of the first and second states.

31. The method of claim 28, further comprising forming a light source.

32. A display device manufactured by the method of claim 28.