METHOD OF MAKING A LIGHT MODULATING DISPLAY DEVICE AND ASSOCIATED TRANSISTOR CIRCUITRY AND STRUCTURES THEREOF

• US 20070229936A1
• Filed: 05/25/2007
• Published: 10/04/2007
• Est. Priority Date: 05/05/1994
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Miles, Mark
• Granted Patent: US 7,532,381 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 26/085 the reflecting means being moved or deformed by electromagnetic means
• CPC Class Codes: G02B 26/0858 the reflecting means being moved or deformed by piezoelectric means
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 6/12 of the integrated circuit kind electric integrated circuits H01L27/00
• CPC Class Codes: G02F 1/13725 based on guest-host interaction G02F1/13762, G02F1/13737, take precedence
• CPC Class Codes: G02F 1/169 based on orientable non-spherical particles having a common optical characteristic, e.g. suspended particles of reflective metal flakes
• CPC Class Codes: G02F 1/216 using liquid crystals, e.g. liquid crystal Fabry-Perot filters
• CPC Class Codes: G02F 2203/03 scattering
• CPC Class Codes: G06F 3/1431 using a single graphics controller
• CPC Class Codes: G06F 3/1446 display composed of modules, e.g. video walls
• CPC Class Codes: G06F 3/147 using display panels
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• 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 3/001 : using specific devices not provided for in groups G09G3/02 - G09G3/36, e.g. using an intermediate record carrier such as a film slide; Projection systems; Display of non-alphanumerical information, solely or in combination with alphanumerical information, e.g. digital display on projected diapositive as background slide projectors per se G03B23/00 = 42 HP
• CPC Class Codes: G09G 3/2014 : by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2074 : using sub-pixels
• CPC Class Codes: G09G 3/2077 : by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/3466 : based on interferometric effect
• CPC Class Codes: G09G 5/02 : characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• CPC Class Codes: H01Q 9/26 : with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength resonant loop antennas H01Q7/00

Abstract

An Interferometric Modulator (IMod) is a microelectromechanical device for modulating light using interference. The colors of these devices may be determined in a spatial fashion, and their inherent color shift may be compensated for using several optical compensation mechanisms. Brightness, addressing, and driving of IMods may be accomplished in a variety of ways with appropriate packaging, and peripheral electronics which can be attached and/or fabricated using one of many techniques. The devices may be used in both embedded and directly perceived applications, the latter providing multiple viewing modes as well as a multitude of product concepts ranging in size from microscopic to architectural in scope.

Claims

1. A light modulator comprising:

a substrate;

a first optical element formed on the substrate, the first modulation element comprising a first cavity; and

a second optical element formed on the substrate, the second modulation element comprising a second cavity,

wherein the cavity of each optical element further comprises a first mirror formed over the substrate and a second mirror separated by a spacing from the first mirror, and further wherein the first optical element in a first state is configured to reflect light comprising a first color, and the second optical element in the first state is configured to reflect light comprising a second color that is different from the first color.

2. The modulator of claim 1, wherein the first state comprises an undriven state.

3. The modulator of claim 1, wherein the first state comprises a driven state.

4. The modulator of claim 1, wherein each optical element further comprises a supporting structure holding the second mirror, wherein the supporting structure of the first optical element comprises a first configuration and the supporting structure of the second optical element comprises a second configuration different from the first configuration.

5. The modulator of claim 1, wherein a first pattern is formed on at least one of the mirrors of the first optical element and a second pattern is formed on at least one of the mirrors of the second optical element, wherein the first pattern is different from the second pattern.

6. The modulator of claim 1, wherein each optical element comprises a supporting structure holding the second mirror, wherein the supporting structure is coupled to a rear surface of the second mirror.

7. A light modulation device, comprising:

a plurality of interferometric modulators formed on a substrate, each interferometric modulator comprising a first mirror formed over the substrate and a second mirror separated by a spacing from the first mirror; and

a driving circuit configured to apply a voltage to first and second interferometric modulators of the plurality of interferometric modulators, wherein the applied voltage causes the second mirror of the first interferometric modulator to move by a first distance, and the same applied voltage causes the second mirror of the second interferometric modulator to move by a second distance, wherein the first and second distances are different.

8. The interferometric modulation device of claim 7, wherein the first and second interferometric modulators comprise first and second support arms supporting the second mirrors, respectively, and the first and second support arms are shaped and dimensioned to allow the second mirror of each interferometric modulator to be displaced by a different amount in response to the same applied voltage.

9. The interferometric modulation device of claim 7, wherein each interferometric modulator comprises a supporting structure holding the second mirror, wherein the supporting structure is coupled to a rear surface of the second mirror.

10. The interferometric modulation device of claim 7, wherein the first mirror and the second mirror of the first and second interferometric modulators have substantially the same spacing separating the first and second mirrors when no voltage is applied.

11. The interferometric modulation device of claim 7, wherein the first interferometric modulator displays a first color when the voltage is applied and the second interferometric modulator displays a second color when the voltage is applied, and further wherein the first and second colors are different.

12. The interferometric modulation device of claim 7, wherein the first interferometric modulator reflects light comprising a first wavelength when the voltage is applied and the second interferometric modulator reflects light comprising a second wavelength when the voltage is applied, and further wherein the first and second wavelengths are different.

13. A method of manufacturing a display device, comprising:

forming at least one interferometric modulator over a substrate, the interferometric modulator comprising a first mirror formed over the substrate and a second mirror separated by a spacing from the first mirror; and

forming at least one transistor circuit on the substrate.

14. The method of claim 13, wherein the spacing between the mirrors at least in part determines a color of light reflected by the interferometric modulator.

15. The method of claim 13, wherein forming the transistor circuit comprises electrically connecting the transistor circuit to the at least one interferometric modulator.

16. The method of claim 13, wherein forming the at least one interferometric modulator and the at least one transistor circuit comprises depositing at least one layer of material to form a portion of the interferometric modulator and a portion of the transistor circuit.

17. The method of claim 16, wherein depositing the material of the at least one deposited layer comprises depositing one or more of amorphous silicon, polysilicon and cadmium selenide.

18. The method of claim 13, further comprising forming an array of a plurality of interferometric modulators on the substrate, wherein forming the transistor circuit comprises forming the transistor circuit in a region that is outside of the array.

19. The method of claim 13, wherein forming the interferometric modulator comprises forming two electrodes, and further wherein the forming the transistor circuit comprises forming a driver circuit configured to supply a voltage to the electrodes to cause the spacing between the mirrors to change.

20. The method of claim 13, wherein the substrate comprises an electrically active material.

21. The method of claim 13, wherein the substrate comprises an electrically inactive material.

22. The method of claim 13, further comprising forming a microelectromechanical switch on the substrate electrically connected to the transistor circuit and/or the interferometric modulator.

23. The method of claim 13, wherein forming the transistor circuit comprises forming a thin film transistor (TFT) circuit.

24. The method of claim 13, wherein the at least one transistor circuit comprises a microprocessor.

25. The method of claim 13, wherein the at least one transistor circuit comprises a memory.

35. The display device of claim 24, further comprising a microelectromechanical switch formed on the substrate electrically connected to the transistor circuit and/or the interferometric modulator.

36. The display device of claim 24, wherein the at least one transistor circuit comprises a microprocessor.

37. The display device of claim 24, wherein the at least one transistor circuit comprises a memory.

38. The display device of claim 24, wherein the transistor circuit comprises a thin film transistor (TFT) circuit.

40. The device of claim 35, wherein the supporting means comprises a transparent substrate.

41. The device of claim 35, wherein the first light modulating means comprises an interferometric modulator configured to reflect light of the first color in the first state.

42. The device of claim 35, wherein the second light modulating means comprises an interferometric modulator configured to reflect light of the second color in the first state.

43. The device of claim 35, further comprising means for driving the first and second light modulating means to be in the first state.

26. A display device comprising:

at least one interferometric modulator formed over a substrate, the interferometric modulator comprising a first mirror formed over the substrate and a second mirror separated by a spacing from the first mirror; and

at least one transistor circuit formed on the substrate.

27. The method of claim 26, wherein the spacing between the mirrors at least in part determines a color of light reflected by the interferometric modulator.

28. The method of claim 26, wherein the transistor circuit is formed to be electrically connected to the at least one interferometric modulator.

29. The display device of claim 26, wherein at least one layer of the interferometric modulator and at least one layer of the transistor circuit comprise common material.

30. The display device of claim 29, wherein the common material of the at least one layer of the interferometric modulator and the transistor circuit comprises one or more of amorphous silicon, polysilicon and cadmium selenide.

31. The display device of claim 26, further comprising an array of a plurality of interferometric modulators, wherein the transistor circuit is formed in a region that is outside of the array.

32. The display device of claim 26, wherein the interferometric modulator further comprises two electrodes, and further wherein the transistor circuit comprises a driver circuit configured to supply a voltage to the electrodes to cause the spacing between the mirrors to change.

33. The display device of claim 26, wherein the substrate comprises an electrically active material.

34. The display device of claim 26, wherein the substrate comprises an electrically inactive material.

39. A device for modulating light, the device comprising:

first means for modulating light;

second means for modulating light; and

a means for supporting the first and second light modulating means,

wherein the first light modulating means reflects light of a first color when the first light modulating means is in a first state and the second light modulating means reflects light of a second color different than the first color when the second light modulating means is in the first state.

44. The device of claim 39, wherein the driving means comprises a driving circuit.