Method and system for driving interferometric modulators

• US 20060067653A1
• Filed: 09/02/2005
• Published: 03/30/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Cummings, William J.
• Granted Patent: US 7,675,669 B2
• Time in Patent Office: Days
• US Class Current: 385/147
• 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: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

Systems and methods for driving a display of MEMS devices are disclosed. In one embodiment, a display includes an array comprising a plurality of interferometric modulators, and a driving circuit coupled to said array, said driving circuit configured to provide actuation signals to drive said array based on a temperature of the display. In another embodiment, a method of driving an array having a plurality of interferometric modulators configured into a display is disclosed, where the method includes sensing the temperature at a predetermined location in display, communicating a signal based on the sensed temperature to a display driver, generating an actuation signal to drive said display based on the received signal, and providing the actuation signal to the array.

Claims

1. A display, comprising:

an array of interferometric modulators; and

a driving circuit coupled to said array, said driving circuit configured to provide actuation signals to drive said array based on temperature.

2. The display of claim 1, wherein the temperature is in the driving circuit, and wherein the temperature correlates to the temperature of the array.

3. The display of claim 2, wherein the temperature is outside of the driving circuit, and wherein the temperature relates to the temperature of the array.

4. The display of claim 2, wherein the temperature is a temperature substantially proximal to the array, and wherein the temperature relates to the temperature of the array.

5. The display of claim 1, further comprising a sensor that senses temperature, said sensor coupled to said driving circuit to provide a signal to said driving circuit corresponding to the temperature.

6. The display of claim 1, wherein said driving circuit comprises a sensor that senses temperature information proximal to the location of said sensor, said sensor being coupled to said driving circuit and configured to communicate the temperature information to said driving circuit, and wherein said driving circuit generates the actuation signals based on the temperature information communicated from said sensor.

7. The display of claim 5, wherein said sensor comprises:

sensor circuitry; and

a sensing element electrically connected to said sensing circuitry, said sensing element configured to be influenced by a temperature and disposed at a location remote from the location of said sensor circuitry,

wherein said sensor circuitry is configured to detect the influence of the temperature on the sensing element, and communicate a signal corresponding to the temperature to said driving circuit, and wherein said driving circuit is configured to generate the actuation signals based on the signal communicated from said sensor circuitry.

8. The display of claim 5, wherein said driving circuit provides actuation signals with an amplitude that is inversely proportional to a change in temperature.

9. The display of claim 1, further comprising a sensor disposed external to said driver circuit that communicates a signal to said driving circuit based on a temperature sensed by said sensor at a location in the display, wherein said driving circuit generates the actuation signals based on the signal communicated from said sensor.

10. The display of claim 1, wherein said array of interferometric modulators comprises support structures, a reflective layer coupled to the supports, an electrode layer, and a gap through which the reflective layer moves in response to an actuation voltage applied between the reflective layer and the electrode layer.

11. The display of claim 1, wherein the signals correspond to actuation voltages that are related to temperature by the following equation:

12. The display of claim 11, wherein σ

(sigma) is the residual stress of Nickel.

13. The display of claim 11, wherein σ

(sigma) is the residual stress of Aluminum.

14. The display of claim 1, further comprising:

a display;

a processor that is in electrical communication with said display, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

15. The display of claim 14, further comprising a driver circuit configured to send at least one signal to said display.

16. The display of claim 14, further comprising a controller configured to send at least a portion of said image data to said driver circuit.

17. The display of claim 14, further comprising an image source module configured to send said image data to said processor.

18. The display of claim 17, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

19. The display of claim 14, further comprising an input device configured to receive input data and to communicate said input data to said processor.

20. A display comprising:

an array of first interferometric modulators;

one or more second interferometric modulators;

a measuring circuit configured to measure an actuation voltage of said one or more second interferometric modulators; and

a first driving circuit coupled to said array of first interferometric modulators and configured to provide driving signals to drive said array of first interferometric modulators based on the actuation voltage measured by said measuring circuit,

wherein said array of first interferometric modulators and said one or more second interferometric modulators have, respectively, a first and a second electromechanical response, wherein said first and second electromechanical responses have a predetermined relationship with each other.

21. The display of claim 20, wherein said measuring circuit is also configured to measure a release voltage of said one or more second interferometric modulators.

22. The display of claim 20, wherein said one or more second interferometric modulators is positioned proximate to said array of first interferometric modulators.

23. The display of claim 20, wherein said array of first interferometric modulators are positioned to output light visible to a viewer and said one or more second interferometric modulators are disposed such that they are not visible to a viewer.

24. The display of claim 20, wherein said first and a second electromechanical response is a function of temperature.

25. The display of claim 20, wherein said predetermined relationship is such that said first and second electromechanical responses are substantially proportional.

26. The display of claim 20, wherein said predetermined relationship is such that said first and second electromechanical responses are substantially equal.

27. The display of claim 20, wherein said array of first interferometric modulators and said one or more second interferometric modulators have substantially the same electromechanical behavior.

28. The display of claim 20, wherein said array of first interferometric modulators and said one or more second interferometric modulators have different electromechanical behaviors.

29. The display of claim 20, wherein said array of first interferometric modulators and said one or more second interferometric modulators have, respectively, a first and a second electrical response function, wherein said first and second electrical responses have a predetermined relationship with each other.

30. The display of claim 29, wherein said predetermined relationship is such that said first and second electrical responses are substantially equal.

31. The display of claim 20, wherein said array of first interferometric modulators and said one or more second interferometric modulators have, respectively, a first and a second mechanical response function, wherein said first and second electrical responses have a predetermined relationship with each other.

32. The display of claim 31, wherein said predetermined relationship is such that said first and second mechanical responses are substantially equal.

33. The display of claim 20, wherein said measuring circuit is configured to measure a capacitance in said one or more second interferometric modulators.

34. The display of claim 20, wherein said measuring circuit is configured to sense a change in the capacitance in said one or more second interferometric modulators.

35. The display of claim 20, further comprising a second driving circuit configured to send driving signals to said one or more second interferometric modulators.

36. The display of claim 34, wherein sensing a change in the capacitance comprises sensing a current pulse in a current flow within said first drive circuitry.

37. The display of claim 20, further comprising:

a display;

a processor that is in electrical communication with said display, said processor being configured to process image data; and

a memory device in electrical communication with said processor.

38. The display of claim 37, further comprising a driver circuit configured to send at least one signal to said display.

39. The display of claim 37, further comprising a controller configured to send at least a portion of said image data to said driver circuit.

40. The display of claim 37, further comprising an image source module configured to send said image data to said processor.

41. The display of claim 40, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

42. The display of claim 37, further comprising an input device configured to receive input data and to communicate said input data to said processor.

43. A method of driving an array of interferometric modulators comprising:

measuring the actuation voltage of one or more test interferometric modulator; and

providing drive signals to an array of display interferometric modulators based on said measured actuation voltage, wherein said display interferometric modulator is configured to output light to a viewer.

44. The method of claim 43, further comprising measuring a release voltage of said one or more test interferometric modulators.

45. The method of claim 43, wherein said providing of drive signals to said array of display interferometric modulators comprises providing drive signals having an voltage levels that are proportional or substantially equal to the measured actuation voltage.

46. The method of claim 43, further comprising providing a test drive signal to said one or more test interferometric modulators wherein said test drive signals have a triangle waveform with an amplitude that is proportional to a voltage level required to actuate said one or more test interferometric modulators.

47. The method of claim 43, further comprising providing a test drive signal to said one or more test interferometric modulators wherein said test drive signal has a frequency that is equal to or proportional to the display frame rate.

48. The method of claim 47, wherein the frequency of said test drive signals is approximately ½

of said display frame rate.

49. The method of claim 43, wherein said measuring comprises measuring a capacitance in said one or more test interferometric modulators.

50. The method of claim 43, wherein said measuring comprises sensing a change in the capacitance in said one or more test interferometric modulators.

51. The method of claim 43, wherein said test drive signal is periodic and said drive signals to said display interferometric modulators are image content specific.

52. A method for manufacturing a display:

forming an array of first interferometric modulators;

forming one or more second interferometric modulators;

providing a measuring circuit configured to measure an actuation voltage of said one or more second interferometric modulators; and

providing a first driving circuit coupled to said array of first interferometric modulators and configured to provide driving signals to drive said array of first interferometric modulators based on the actuation voltage measured by said measuring circuit.

53. The method of claim 52, further comprising forming said array of first interferometric modulators in an area that is visible to a viewer and forming said one or more second interferometric modulators in an area of said display that is not visible to said viewer.

69. A display formed by the method of claim 52.

54. A method of driving an array having a plurality of interferometric modulators configured into a display, said method comprising:

sensing a temperature at a predetermined location in the display;

communicating a sensor signal based on the sensed temperature to a display driver;

generating an actuation signal in the display driver based on the sensor signal; and

providing the actuation signal to the array.

55. The method of claim 54, wherein the temperature is sensed at a location in the array.

56. The method of claim 54, wherein the temperature is sensed in the display driver.

57. The method of claim 54, wherein generating an actuation signal comprises generating an actuation signal with an amplitude component inversely proportional to a change in the sensed temperature.

58. A display, comprising:

means for displaying image data; and

means providing actuation signals to drive said displaying means based on a temperature of the display.

59. The display of claim 58, wherein the displaying means comprise an array comprising a plurality of interferometric modulators.

60. The display of claim 58, wherein the providing means comprise an array controller.

61. The display of claim 58, further comprising:

means for sensing the temperature; and

means for communicating a signal corresponding to the temperature to said providing means.

62. The display of claim 61, wherein said sensing means comprise a sensor.

63. The display of claim 61, wherein said communicating means comprises an electrical connection between said sensor and said providing means.

64. The display of claim 61, further comprising:

means for determining the voltage required to actuate a interferometric modulator subject to the temperature; and

means for communicating a signal corresponding to the actuation voltage to the providing means.

65. The display of claim 64, wherein said determining means comprises:

a test interferometric modulator; and

test circuitry coupled to said test interferometric modulator, said test circuitry configured to determine the voltage required to actuate said test interferometer.

66. The display of claim 64, wherein said communicating means comprises said test circuitry connected electrically to said providing means, and configured to communicate a signal corresponding to the voltage required to activate said test interferometric modulator to said providing means.

67. A method of manufacturing a display, the method comprising:

forming an array comprising a plurality of interferometric modulators; and

coupling a driving circuit to said array, said driving circuit configured to provide actuation signals to drive said array based on a temperature of the display.

68. A display manufactured by the method of claim 67.

70. A display, comprising:

a first means for modulating light;

a second means for modulating light;

means to measure an actuation voltage of said second means for modulating light; and

means for driving said first means for modulating light, said driving means coupled to said first means for modulating light and configured to provide driving signals to drive said first modulating means based on the actuation voltage measured by said measuring means,

wherein said first means for modulating light and said second means for modulating light have, respectively, a first and a second electromechanical response,

wherein said first and second electromechanical responses have a predetermined relationship with each other.

71. The display of claim 70, wherein the first modulating means comprises an array of first interferometric modulators.

72. The display of claim 70, wherein the second modulating means comprises one or more second interferometric modulators.

73. The display of claim 70, wherein the measuring means comprises a measuring circuit.

74. The display of claim 70, wherein the driving means comprises a first driving circuit.

75. A method of driving a display of interferometric modulators comprising:

measuring a transition voltage of one or more of a plurality of interferometric modulators of the display;

determining a drive voltage for operating the plurality of the interferometric modulators based on the measured transition voltage; and

providing said determined drive voltage to the plurality of interferometric modulators.

76. The method of claim 75, wherein the measured transition voltage is a voltage at which at least one of the interferometric modulators transitions to a relaxed state.

77. The method of claim 75, wherein the measured transition voltage is a voltage at which at least one of the interferometric modulators transitions to an actuated state.

78. The method of claim 75, wherein the measured transition voltage is affected by the temperature of at least one of the interferometric modulators, changes in the electromechanical properties of at least one of the interferometric modulators, or by electrical charge buildup within at least one of the interferometric modulators.

79. The method of claim 75, wherein said measuring operation measures the transition voltage of one or more interferometric modulators disposed in two or more non-contiguous areas of the display.

80. The method of claim 75, wherein said plurality of interferometric modulators of the display are arranged in a matrix of rows and columns, and wherein said measuring operation measures the transition voltage of one or more of the interferometric modulators located in one of the rows.

81. The method of claim 75, wherein said plurality of interferometric modulators of the display are arranged in a matrix of rows and columns, and wherein said measuring operation measures the transition voltage of one or more interferometric modulator located in two or more of the rows.

82. The method of claim 81, wherein a first row of said two or more rows is disposed near in an upper portion of the display and a second row of said two or more rows is disposed in a lower portion of the display.

83. The method of claim 75, wherein said plurality of interferometric modulators of the display are arranged in a plurality of lines in said display, and wherein said measuring operation measures the transition voltage of one or more interferometric modulator located in one of the plurality of lines.

84. A system of driving a display of interferometric modulators comprising:

a sensor circuit configured to measure a transition voltage of one or more of a plurality of interferometric modulators in the display, and said sensor circuit also configured to determine a drive voltage for operating the plurality of interferometric modulators based on the measured transition voltage; and

a drive circuit coupled to said sensor circuit and configured to provide the determined drive voltage to the plurality of interferometric modulators.

85. The system of claim 84, wherein the measured transition voltage is a voltage at which at least one of the interferometric modulators transitions to a relaxed state.

86. The system of claim 84, wherein the measured transition voltage is a voltage at which at least one of the interferometric modulators transitions to an actuated state.

87. The system of claim 84, wherein said plurality of interferometric modulators of the display are arranged in a plurality of lines in said display, and wherein said measuring operation measures the transition voltage of one or more interferometric modulator located in one of the plurality of lines.

88. A system of driving a display of interferometric modulators comprising:

means for measuring a transition voltage of one or more of a plurality of interferometric modulators in the display;

means for determining a drive voltage for operating the plurality of the interferometric modulators based on the measured transition voltage; and

means for providing the determined drive voltage to the plurality of interferometric modulators.

89. The system of claim 88, wherein said measuring means comprises a sensor circuit.

90. The system of claim 88, wherein said determining means comprises a logic circuit.

91. The system of claim 88, wherein said providing means comprises a drive circuit.