Sequence and timing control of writing and rewriting pixel memories for achieving higher number of gray scales

• US 7,215,460 B2
• Filed: 07/16/2005
• Issued: 05/08/2007
• Est. Priority Date: 11/01/2003
• Status: Active Grant

• Current Assignee: Ignite USA (Ignite)
• Original Assignee: Silicon Quest Kabushiki-Kaisha
• Inventors: Ishii, Fusao
• Primary Examiner(s): THOMPSON, TIMOTHY J
• Application Number:
  US11/183,216
• Publication Number:
  US 20050254116A1
• Time in Patent Office: 661 Days
• Field of Search: 359/290, 359/291, 359/223, 359/224, 359/318, 359/292, 359/295
• US Class Current: 359/291
• 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 a lower driving voltage is disclosed. The lower driving voltage is achieved by projecting a partial light for image display during a micromirror is oscillating from fully on state to a fully off state. The micromirror device includes a reflective element supported on a hinge for oscillating and positioning at least three states. These three states are a fully on state, a fully off state, and a partially ON angular positions in responding to a digital control signal. The oscillation of the micromirrors is controlled in responding to a digital control signal wherein the digital control signal is controlled for writing into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image.

Claims

1. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating and positioning at least a fully on, a fully off and an partially ON angular positions in responding to a digital control signal wherein said digital control signal is controlled for writing into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image; and

said interleave-and-jump sequence comprising a sequence to jump either back or forth multiple lines to non-sequential lines of a display image.

2. The device of claim 1, wherein:

said reflecting element is further provided for oscillating to different positions in responding to a two-bit digital control signal.

3. The device of claim 1, further comprising:

two electrodes and said reflecting element is further provided for oscillating to different positions in responding to a digital control signal for changing voltages of said two electrodes.

4. The device of claim 1, further comprising:

two electrodes and said reflecting element is further provided for oscillating to different positions in responding to a digital control signal representing by two digital bits with one bit applied to each of said two electrodes for changing voltages of said two electrodes.

5. The device of claim 1, wherein:

said reflecting element is further controlled to change an oscillation direction in an intermediate angular position between said fully on and fully off angular positions.

6. 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.

7. 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.

8. The device of claim 1, further comprising:

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

9. The device of claim 1, further comprising:

two separate independently controllable electrodes disposed on two opposite sides of said hinge wherein 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.

10. The device of claim 9, 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.

11. The device of claim 10, 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.

12. The device of claim 10, 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.

13. The device of claim 10, 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.

16. The device of claim 1 further comprising:

a pulse width modulation (PWM) control circuit for receiving a series of PWM control words of different number of bits as a pulse width modulation PWM signal to control said reflecting element at said fully-ON and fully-Off angular positions for controlling a gray scale of display wherein said PWM control circuit further receiving said digital control signal as an oscillation signal for superimposing on said PWM signal for oscillating said reflecting element to said partially-ON angular position for further controlling said gray scale of display.

17. The device of claim 16 wherein:

said digital control signal for oscillating said reflecting element to a partially-ON angular position is inserted into a time slot controlled by a most significant bit (MSB) of said PWM control words.

18. The device of claim 16 wherein:

said digital control signal for oscillating said reflecting element to a partially-ON angular position is inserted into a time slot controlled by a number of bits ranging between a least significant bit (LSB) and a most significant bit (MSB) of said PWM control words.

19. The device of claim 16 wherein:

said digital control signal for oscillating said reflecting element to a partially-ON angular position is inserted into a time-gap slot between the time periods between a least significant bit (LSB) and a most significant bit (MSB) of said PWM control words.

21. The device of claim 1 further comprising:

a pulse width modulation (PWM) control circuit for receiving a series of PWM control words of different number of bits as a pulse width modulation PWM signal to control said reflecting element at said fully-ON and fully-Off angular positions for controlling a gray scale of display wherein said PWM control circuit further receiving said digital control signal as an oscillation signal for superimposing on said PWM signal for oscillating said reflecting element to said partially-ON angular position for further controlling said gray scale of display; and

said PWM control words having a maximum number of bits of M to control a maximum number of 2^M PWM controlled gray scales and said oscillating signal for controlling said reflecting element to a partially-ON angular position further increasing a maximum number of controllable gray scale to 2^(M+N) where N is a positive integer.

22. The device of claim 19 wherein:

said PWM control words having a maximum number of seven bits and said N is three for providing a maximum controllable gray scale of 2¹⁰.

23. The device of claim 1 wherein:

said digital control signal is controlled for writing and rewriting into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image wherein a time duration for writing and rewriting said display pixels in said multiple lines are determined to satisfy a minimum flickering-prevention display frequency.

14. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating and positioning at least a fully on, a fully off and an partially ON angular positions in responding to a digital control signal wherein said digital control signal is controlled for writing into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image; and

said interleave-and-jump sequence comprising a sequence to jump either back or forth multiple horizontal lines to non-sequential horizontal lines of a display image.

15. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating and positioning at least a fully on, a fully off and an partially ON angular positions in responding to a digital control signal wherein said digital control signal is controlled for writing into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image; and

said interleave-and-jump sequence comprising a sequence to jump either back or forth multiple vertical lines to non-sequential vertical lines of a display image.

20. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating and positioning at least a fully on, a fully off and an partially ON angular positions in responding to a digital control signal wherein said digital control signal is controlled for writing into display pixels in an interleave-and-jump sequence to jump multiple lines to non-sequential lines of a display image; and

said interleave-and-jump sequence further comprising a sequence to jump either back or forth multiple lines to non-sequential lines of a display image for writing to said pixels in said non-sequential lines at different writing speeds.