Display methods and apparatus

• US 8,159,428 B2
• Filed: 01/06/2006
• Issued: 04/17/2012
• Est. Priority Date: 02/23/2005
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Hagood, Nesbitt W., McAllister, Abraham, Lewis, Stephen R., Barton, Roger W.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Said, Mansour M
• Application Number:
  US11/326,900
• Publication Number:
  US 20060256039A1
• Time in Patent Office: 2,293 Days
• Field of Search: 345 83- 84, 345 87- 88, 345/90, 345/92, 345 95- 96, 345/100, 345108-109, 345/48, 359/198, 359/230, 359/233, 359/290
• US Class Current: 345/84
• CPC Class Codes: G02B 26/02 for controlling the intensity of light G02B26/004 takes precedence
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2300/0885 Pixel comprising a non-linear two-terminal element alone in series with each display pixel element
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0262 The addressing of the pixel, in a display other than an active matrix LCD, involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependent on signals of two data electrodes
• CPC Class Codes: G09G 2310/063 Waveforms for resetting the whole screen at once
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: H04N 5/7416 involving the use of a spatial light modulator, e.g. a light valve, controlled by a video signal

Abstract

The invention relates to methods and apparatus for forming images on a display utilizing a control matrix to control the movement of MEMs-based light modulators.

Claims

1. A display apparatus comprising:

an array of pixels arranged in rows and columns including

a transparent substrate, and

a plurality of MEMS-based light modulators; and

a control matrix disposed on the substrate including,

a common electrical connection among a set of pixels for providing a common voltage to each of the pixels in the set of pixels, the set of pixels including pixels in at least two of the columns and in at least two of the rows,

a data voltage interconnect corresponding to one of the columns, and

a switch incorporated into one of the pixels for controlling actuation of a corresponding MEMS-based light modulator in response to a voltage applied by the data voltage interconnect

wherein at least one pixel in the array of pixels includes a first actuator for driving the MEMS-based light modulator in to a first state and a second actuator for driving the MEMS-based light modulator into a second state.

2. The display apparatus of claim 1, wherein the common electrical connection is a global actuation interconnect.

3. The display apparatus of claim 1, comprising a global actuation voltage source for applying a global actuation voltage to the common electrical connection.

4. The display apparatus of claim 1, wherein the common electrical connection comprises a common current drain for accepting charge stored in the pixels in the array of pixels, thereby allowing for actuation of the plurality of corresponding MEMS-based light modulators.

5. The display apparatus of claim 1, wherein the MEMS-based light modulators comprise shutter assemblies.

6. The display apparatus of claim 5, wherein the shutter assemblies are electrically bi-stable.

7. The display apparatus of claim 5, wherein the shutter assemblies are mechanically bi-stable.

8. The display apparatus of claim 1, wherein application of a data voltage to the data voltage interconnect substantially reduces a minimum additional voltage change needed to actuate one of the MEMS-based light modulators.

9. The display apparatus of claim 8, wherein the common electrical connection supplies the minimum additional voltage change.

10. The display apparatus of claim 1, wherein the one pixel comprises a memory element, and wherein the switch corresponding to the pixel controls the storage of the data voltage by the memory element.

11. The display apparatus of claim 1, wherein the common electrical connection supplies a bias voltage to the set of pixels.

12. The display apparatus of claim 1, wherein the switch comprises a transistor.

13. The display apparatus of claim 1, wherein at least one pixel in the array of pixels includes a memory element for storing a light modulator movement instruction.

14. The display apparatus of claim 13, wherein the memory element comprises a capacitor.

15. A method of forming an image on a display, comprising:

selecting a first scan-line of the display, wherein the scan line includes a plurality of pixels;

for at least a first pixel of the plurality of pixels in the selected scan line, selectively regulating a voltage across a first actuator via a first switch disposed on a transparent substrate, thereby enabling the first actuator to drive a corresponding MEMS-based light modulator into a first state;

selecting a second scan line of the display including a second plurality of pixels;

for at least a second pixel of the second plurality of pixels in the selected second scan line, selectively regulating a voltage across a second actuator via a second switch, thereby enabling the second actuator to drive a corresponding second MEMS-based light modulator into a second state;

applying a global actuation voltage to a global actuation interconnect shared among at least two pixels in the first scan line and at least two pixels in the second scan line, thereby actuating the first and second enabled actuators; and

directing light towards at least one of the MEMS-based light modulators to form an image.

16. The method of claim 15, wherein the global actuation interconnect provides a common current drain for accepting charge stored in the pixels in the array of pixels, thereby allowing for actuation of the enabled actuators.

17. The method of claim 15, wherein the first and second MEMS-based light modulators comprise shutter assemblies.

18. The method of claim 17, wherein the shutter assemblies are electrically bi-stable.

19. The method of claim 17, wherein the shutter assemblies are mechanically bi-stable.

20. The method of claim 17, wherein driving the first and second MEMS-based light modulators into first and second states comprises moving shutters incorporated into the respective shutter assemblies in a plane parallel to a substrate on which the shutters assemblies are formed.

21. The method of claim 15, wherein the voltage across the first actuator is regulated by the application of a data voltage to the first switch.

22. The method of claim 21, wherein the magnitude of the voltage regulated by the switch is substantially greater than the magnitude of the data voltage.

23. The method of claim 15, wherein enabling the first and second actuators comprises substantially reducing the additional minimum voltage change needed to be applied across the first and second actuators to actuate the first and second actuators.

24. The method of claim 23, wherein the global actuation voltage supplies the minimum additional voltage change.

25. A display apparatus comprising:

an array of pixels arranged in rows and columns including

a transparent substrate, and

a plurality of MEMS-based light modulators; and

a control matrix disposed on the substrate including,

a common electrical connection among a set of pixels for providing a common voltage to each of the pixels in the set of pixels, the set of pixels including pixels in at least two of the columns and in at least two of the rows, wherein the common electrical connection comprises a common current drain for accepting charge stored in the pixels in the array of pixels, thereby allowing for actuation of the plurality of corresponding MEMS-based light modulators,

a data voltage interconnect corresponding to one of the columns, and

a switch incorporated into one of the pixels for controlling actuation of a corresponding MEMS-based light modulator in response to a voltage applied by the data voltage interconnect.

26. The display apparatus of claim 25, wherein the common electrical connection is a global actuation interconnect.

27. The display apparatus of claim 25, comprising a global actuation voltage source for applying a global actuation voltage to the common electrical connection.

28. The display apparatus of claim 25, wherein the MEMS-based light modulators comprise shutter assemblies.

29. The display apparatus of claim 28, wherein the shutter assemblies are electrically bi-stable.

30. The display apparatus of claim 28, wherein the shutter assemblies are mechanically bi-stable.

31. The display apparatus of claim 25, wherein application of a data voltage to the data voltage interconnect substantially reduces a minimum additional voltage change needed to actuate one of the MEMS-based light modulators.

32. The display apparatus of claim 31, wherein the common electrical connection supplies the minimum additional voltage change.

33. The display apparatus of claim 25, wherein at least one pixel in the array of pixels includes a first actuator for driving the MEMS-based light modulator into a first state and a second actuator for driving the MEMS-based light modulator into a second state.

34. The display apparatus of claim 25, wherein the one pixel comprises a memory element, and wherein the switch corresponding to the pixel controls the storage of the data voltage by the memory element.

35. The display apparatus of claim 25, wherein the common electrical connection supplies a bias voltage to the set of pixels.

36. The display apparatus of claim 25, wherein the switch comprises a transistor.

37. The display apparatus of claim 25, wherein at least one pixel in the array of pixels includes a memory element for storing a light modulator movement instruction.

38. The display apparatus of claim 37, wherein the memory element comprises a capacitor.

39. A display apparatus comprising:

an array of pixels arranged in rows and columns including

a transparent substrate, and

a plurality of MEMS-based light modulators; and

a control matrix disposed on the substrate including,

a common electrical connection among a set of pixels for providing a common voltage to each of the pixels in the set of pixels, the set of pixels including pixels in at least two of the columns and in at least two of the rows,

a data voltage interconnect corresponding to one of the columns, and

a switch incorporated into one of the pixels for controlling actuation of a corresponding MEMS-based light modulator in response to a voltage applied by the data voltage interconnect, wherein application of a data voltage to the data voltage interconnect substantially reduces a minimum additional voltage change needed to actuate one of the MEMS-based light modulators.

40. The display apparatus of claim 39, wherein the common electrical connection is a global actuation interconnect.

41. The display apparatus of claim 39, comprising a global actuation voltage source for applying a global actuation voltage to the common electrical connection.

42. The display apparatus of claim 39, wherein the common electrical connection comprises a common current drain for accepting charge stored in the pixels in the array of pixels, thereby allowing for actuation of the plurality of corresponding MEMS-based light modulators.

43. The display apparatus of claim 39, wherein the MEMS-based light modulators comprise shutter assemblies.

44. The display apparatus of claim 43, wherein the shutter assemblies are electrically bi-stable.

45. The display apparatus of claim 43, wherein the shutter assemblies are mechanically bi-stable.

46. The display apparatus of claim 39, wherein the common electrical connection supplies the minimum additional voltage change.

47. The display apparatus of claim 39, wherein at least one pixel in the array of pixels includes a first actuator for driving the MEMS-based light modulator into a first state and a second actuator for driving the MEMS-based light modulator into a second state.

48. The display apparatus of claim 39, wherein the one pixel comprises a memory element, and wherein the switch corresponding to the pixel controls the storage of the data voltage by the memory element.

49. The display apparatus of claim 39, wherein the common electrical connection supplies a bias voltage to the set of pixels.

50. The display apparatus of claim 39, wherein the switch comprises a transistor.

51. The display apparatus of claim 39, wherein at least one pixel in the array of pixels includes a memory element for storing a light modulator movement instruction.

52. The display apparatus of claim 51, wherein the memory element comprises a capacitor.