Micromirrors with lower driving voltages

• US 7,268,932 B2
• Filed: 05/04/2005
• Issued: 09/11/2007
• Est. Priority Date: 11/01/2003
• Status: Expired due to Fees

• Current Assignee: Ignite USA (Ignite), Silicon Quest Kabushiki-Kaisha
• Original Assignee: Silicon Quest Kabushiki-Kaisha
• Inventors: Ishii, Fusao
• Primary Examiner(s): Thomas; Brandi N.
• Application Number:
  US11/121,543
• Publication Number:
  US 20050190429A1
• Time in Patent Office: 860 Days
• Field of Search: 359/290, 359/291, 359/292, 359/295, 359/298, 359/294, 359/115, 359/116, 359/223, 359/224, 359/214, 359/230, 359/231
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 27/09 Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for adapting the beam shape of a laser diode G02B19/0052; adapting the beam shape of an LED G02B19/0061; coupling into light guides using intermediate optical elements G02B6/4204; beam shaping specially adapted for lasers H01S3/005
• CPC Class Codes: G03B 21/008 using micromirror devices
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• 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 5/7458 the modulator being an array of deformable mirrors, e.g. digital micromirror device [DMD]
• CPC Class Codes: H04N 9/3114 by using a sequential colour filter producing one colour at a time
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406

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 by a two bits signal inputted to two electrodes for controlling the voltage of these electrodes respectively. The micromirrors are further controlled to change the oscillation direction at an angular position between the fully on and fully off positions at a fraction of an oscillation cycle. With these inventive features, the micromirrors are controllable to provide higher ranges of gray scales without increasing the driving voltage.

Claims

1. A micromirror device comprising:

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

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;

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; and

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.

2. The device of claim 1, 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 a digital control signal.

3. 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.

4. The device of claim 1, 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 a digital control signal 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.

5. 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.

6. The device of claim 1, 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.

7. The device of claim 1, 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 said three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to three different positions of fully-ON, fully-OFF and an intermediate states.

8. A micromirror device comprising:

a reflecting element supported on a hinge for oscillating between two states wherein said reflecting elements is further controlled to stop or oscillate in a reverse direction before reaching either of said two states;

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;

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; and

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.

9. The device of claim 8, wherein:

said reflecting element is further controlled to stop at a third intermediate state between said two states.

10. The device of claim 8, wherein:

said reflecting element is further provided to oscillate to said two states as a fully on, a fully off states respectively and further stoppable at an intermediate partially ON angular positions in responding to a digital control signal.

11. The device of claim 8, wherein:

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

12. The device of claim 8, wherein:

said reflecting element is further provided to oscillate said two states as a fully on, a fully off states respectively in responding to a digital control signal wherein said reflecting element is further digitally controllable to change an oscillation direction in an intermediate angular position between said fully on and fully off angular positions.

13. The device of claim 8, 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.

14. The micromirror device of claim 8 further comprising:

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

15. The device of claim 8, 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 said three digital signals represented by (1,0), (0,1) and (0,0) for controlling said reflecting element to oscillate to three different positions.