Control of micromirrors with intermediate states

• US 7,304,783 B2
• Filed: 05/23/2005
• Issued: 12/04/2007
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Fusao Ishii
• Inventors: Ishii, Fusao
• Primary Examiner(s): Mack; Ricky
• Assistant Examiner(s): THOMAS, BRANDI N
• Application Number:
  US11/136,041
• Publication Number:
  US 20050206992A1
• Time in Patent Office: 925 Days
• Field of Search: 359/291, 359/290, 359/292, 359/295, 359/298, 359/296, 359/297
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0852 being a dynamic memory with more than one capacitor
• CPC Class Codes: G09G 2310/02 Addressing, scanning or driving the display screen or processing steps related thereto
• 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 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2037 with specific control of sub-frames corresponding to the least significant bits
• CPC Class Codes: G09G 3/2077 by a combination of two or more gradation control methods
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: H04N 2005/7466 Control circuits therefor
• CPC Class Codes: H04N 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]

Abstract

A micromirror device with at least one intermediate state is disclosed in this invention with the reflecting mirror placed at an angular position between a fully on angle and fully off angle. The micromirror device includes a reflecting element supported on a hinge for oscillating and positioning at least three angular positions. The micromirror device further has a control circuit for receiving a series of control words of different number of bits as a time modulation signal to control the reflecting element for controlling a gray scale of display wherein the control circuit further receiving an oscillation signal for superimposing on the time modulation signal for oscillating the reflecting element for further controlling the gray scale of display. The series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits of a least number of bits to a maximum number of bits with a time gap between each of the control words. The oscillating signal may be inserted optionally into a gap between the control words, into every control word, into a control word of the MSB, or into a control word of the LSB, In a preferred embodiment, the oscillating signal is applied to dispose the reflecting element at an intermediate state with a zero degree relative to an incident light.

Claims

1. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating and positioning at least three angular positions; and

a control circuit for receiving a series of control words of different number of bits as a time modulation signal to control said reflecting element for controlling a gray scale of display wherein said control circuit further receiving an oscillation signal for superimposing on said time modulation signal for oscillating said reflecting element for further controlling said gray scale of display; and

said oscillating signal is provided for controlling said reflecting element to oscillated to a fully on, a fully off and an partially ON angular positions wherein said reflecting element is further controlled by said oscillating signal to change an oscillation direction in an intermediate angular position between said fully on and fully off angular positions.

2. The device of claim 1, wherein:

said series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits.

3. The device of claim 1, wherein:

said series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits with a time gap between each of said control words.

4. The device of claim 3, wherein:

said oscillating signal is received as a two bit signal.

5. The device of claim 3, wherein:

said oscillating signal is inserted into everyone of said series of control words.

6. The device of claim 3, wherein:

said oscillating signal is inserted into a gap between said control words.

7. The device of claim 3, wherein:

said oscillating signal is inserted into a control word of said least number of bits.

8. The device of claim 3, wherein:

said oscillating signal is inserted into a control word of said maximum number of bits.

9. The device of claim 3, wherein:

said oscillating signal is inserted into a gap between every two of said control words.

10. The device of claim 3, wherein:

said oscillating signal is applied to dispose said reflecting element at an intermediate state with a zero degree relative to an incident light.

11. The device of claim 1, wherein:

said reflecting element is further provided for oscillating to said fully on, a fully off and an partially ON angular positions in responding to said series of control words and said oscillating signal inputted as digital control signals.

12. The device of claim 1, wherein:

said reflecting element is further controlled by said oscillating signal inputted as a two-bit digital control signal.

13. The device of claim 1, further comprising:

two electrodes for inputting said oscillating signal for oscillating said reflecting element to different positions.

14. The device of claim 1, further comprising:

two electrodes for inputting said oscillating signal representing by two digital bits with one bit applied to each of said two electrodes for changing a voltage applied thereon for oscillating said reflecting element to different positions.

15. The device of claim 1, further comprising:

a lens for receiving an incident light projection from said reflecting element for projecting an image display light wherein said lens is further disposed for projecting a portion of said image display light as said reflecting element oscillating between a fully on and fully off angular positions.

16. The micromirror device of claim 1 further comprising:

a vacuum seal package for enclosing said reflecting element and said hinge in a sealed vacuum space.

17. The device of claim 1, further comprising:

two separate independently controllable electrodes for inputting said oscillating signal for controlling said reflecting element to oscillate to different positions.

18. The device of claim 1, further comprising:

two separate independently controllable electrodes for inputting said oscillating signal wherein said two separate independently controllable electrodes disposed on two opposite sides of said hinge and each of said electrodes is connected to a control circuit for independently applying a control voltage thereon to control said reflecting element to oscillate to different positions.

19. The device of claim 18, wherein:

each of said electrodes is connected to a transistor having a gate connected to a common wordline and each transistor having a source connected to an independently controllable bitline for independently controlling said reflecting element to oscillate to different positions.

20. The device of claim 19, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for independently controlling said reflecting element to oscillate to different positions.

21. The device of claim 19, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for applying one of three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to three different positions.

22. The device of claim 19, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for applying one of three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to angular positions oriented substantially at a positive angle, a negative angle and 0°

relative to a perpendicular axis to said reflecting element.

23. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating between two states wherein said reflecting elements is projecting a partial light for contributing to a display light intensity during oscillating between either of said two states;

a control circuit for receiving a series of control words of different number of bits as a time modulation signal to control said reflecting element for controlling a gray scale of display wherein said control circuit further receiving an oscillation signal for superimposing on said time modulation signal for oscillating said reflecting element for further controlling said gray scale of display; and

said oscillating signal is provided for controlling said reflecting element to oscillated to a fully on, a fully off and an partially ON angular positions wherein said reflecting element is further controlled by said oscillating signal to change an oscillation direction in an intermediate angular position between said fully on and fully off angular positions.

24. The device of claim 23, wherein:

said series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits.

25. The device of claim 23, wherein:

said series of control words further includes a sequence of control words of a least number of bits to a maximum number of bits with a time gap between each of said control words.

26. The device of claim 23, wherein:

said oscillating signal is received as a two bit signal.

27. The device of claim 25, wherein:

said oscillating signal is inserted into everyone of said series of control words.

28. The device of claim 25, wherein:

said oscillating signal is inserted into a gap between said control words.

29. The device of claim 25, wherein:

said oscillating signal is inserted into a control word of said least number of bits.

30. The device of claim 25, wherein:

said oscillating signal is inserted into a control word of said maximum number of bits.

31. The device of claim 25, wherein:

said oscillating signal is inserted into a gap between every two of said control words.

32. The device of claim 25, wherein:

said oscillating signal is applied to dispose said reflecting element at an intermediate state with a zero degree relative to an incident light.

33. The device of claim 23, wherein:

said partial light for contributing to a display light intensity is further applied by using said oscillation signal for controlling a gray scale of an image display using a light projected from said reflecting element.

34. The device of claim 23, wherein:

said reflecting element is further provided for oscillating to a fully on, a fully off and an partially ON angular positions in responding to said series of control words and said oscillating signal inputted as digital control signals.

35. The device of claim 23, wherein:

said reflecting element is further controlled by said oscillating signal inputted as a two-bit digital control signal.

36. The device of claim 23, further comprising:

two electrodes for inputting said oscillating signal for oscillating said reflecting element to different positions.

37. The device of claim 23, further comprising:

two electrodes for inputting said oscillating signal representing by two digital bits with one bit applied to each of said two electrodes for changing a voltage applied thereon for oscillating said reflecting element to different positions.

38. The device of claim 23, further comprising:

a lens for receiving an incident light projection from said reflecting element for projecting an image display light wherein said lens is further disposed for projecting a portion of said image display light as said reflecting element oscillating between a fully on and fully off angular positions.

39. The micromirror device of claim 23 further comprising:

a vacuum seal package for enclosing said reflecting element and said hinge in a sealed vacuum space.

40. The micromirror device of claim 23, further comprising:

two separate independently controllable electrodes for inputting said oscillating signal for controlling said reflecting element to oscillate to different positions.

41. The micromirror device of claim 23, further comprising:

two separate independently controllable electrodes for inputting said oscillating signal wherein said two separate independently controllable electrodes disposed on two opposite sides of said hinge and each of said electrodes is connected to a control circuit for independently applying a control voltage thereon to control said reflecting element to oscillate to different positions.

42. The micromirror device of claim 41, wherein:

each of said electrodes is connected to a transistor having a gate connected to a common wordline and each transistor having a source connected to an independently controllable bitline for independently controlling said reflecting element to oscillate to different positions.

43. The micromirror device of claim 42, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for independently controlling said reflecting element to oscilate to different positions.

44. The micromirror device of claim 42, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for applying one of three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to three different positions.

45. The micromirror device of claim 42, wherein:

each bitline connected to said source of said transistor is provided for receiving a binary bit represented by zero and one for applying a voltage to said electrodes for applying one of three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to angular positions oriented substantially at a positive angle, a negative angle and 0°

relative to a perpendicular axis to said reflecting element.

46. The micromirror device of claim 23, further comprising:

said control circuit operated at a voltage substantially about five volts for controlling said reflecting element to oscillate to different positions.

47. The micromirror device of claim 23, wherein:

said control circuit further receiving said control words having a maximum number of bits of at least ten bits for operating at a voltage substantially about twenty volts for controlling said reflecting element to oscillate to different positions.

48. The micromirror device of claim 23, wherein:

said micromirror device further constituting a CMOS micromirror device.

49. The micromirror device of claim 23, wherein:

said micromirror device further constituting a DMOS micromirror device.

50. The micromirror device of claim 23, wherein:

said micromirror device further constituting a PMOS micromirror device.

51. The micromirror device of claim 23, wherein:

said micromirror device further constituting a NMOS micromirror device.

52. The micromirror device of claim 23, wherein:

said reflecting element further comprising a multiple layer reflecting surface for improving reflectance from said reflecting element.

54. The method of claim 49, further comprising:

applying a CMOS integrate circuit manufacturing process for manufacturing said micromirror device.

53. A method for controlling a micromirror device comprising:

disposing a reflecting element supported on a hinge to oscillate between two states and enabling said reflecting elements to project a partial light for contributing to a display light intensity during oscillating between either of said two states;

receiving a series of control words of different number of bits as a time modulation signal to control said reflecting element for controlling a gray scale of display;

receiving an oscillation signal for superimposing on said time modulation signal for oscillating said reflecting element for further controlling said gray scale of display; and

controlling said reflecting element by said oscillating signal to oscillate to a fully on, a fully off and an partially ON angular positions and further controlling said reflecting element by said oscillating signal to change an oscillation direction in an intermediate angular position between said fully on and fully off angular positions.