Digital micromirror device with simplified drive electronics for use as temporal light modulator

• US 7,187,484 B2
• Filed: 12/30/2002
• Issued: 03/06/2007
• Est. Priority Date: 12/30/2002
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mehrl, David J.
• Primary Examiner(s): Schwartz; Jordan
• Assistant Examiner(s): STULTZ, JESSICA T
• Application Number:
  US10/331,813
• Publication Number:
  US 20040125431A1
• Time in Patent Office: 1,527 Days
• Field of Search: 359233- 34, 359290- 92, 359/298, 359310- 11, 345 84- 85, 345/108, 345/30, 345/55, 345 84- 5
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A digital micromirror device (DMD) modified for use as a temporal light modulator. The DMD is modified so that the mirrors of the DMD have a preferential tilt direction. The inputs and outputs of the DMD are connected to common ground, except for the bias input lines. The latter are connected to a common excitation input, which is used to cyclically reposition the mirrors between tilted and flat states.

Claims

1. A device comprising:

an array of tiltable mirrors, each said mirror designed to deflect from an unenergized position in at least two directions;

a hinge associated with each said mirror, said hinge formed in a substantially neutral position and substantially held in a deformed position until acquiring a preferential set, said preferential set being a deviation from said neutral position in the absence of external forces or applied voltages; and

at least one excitation voltage input connection, wherein a signal applied to said excitation voltage input connection deflects said mirror in a preferential tilt direction determined by said preferential set.

2. The device of claim 1, wherein all mirrors have the same preferential tilt direction.

3. The device of claim 1, wherein one half of the mirrors have a preferential tilt in the on direction and one half of the mirrors have a preferential tilt in the off direction.

4. The device of claim 1, wherein the array has a single excitation voltage input connection.

5. The device of claim 1, wherein the mirrors are arranged in reset groups and the reset groups have at least two different excitation voltage input connections.

6. The digital micromirror device of claim 1, wherein said preferential tilt direction is controlled by a residual hinge torque.

7. A light modulating unit, comprising:

a micromirror device having an array of tiltable mirrors, each said mirror designed to deflect from an unenergized position in at least two directions;

a hinge associated with each said mirror, said hinge formed in a substantially neutral position and substantially held in a deformed position until acquiring a preferential set, said preferential set being a deviation from said neutral position in the absence of external forces or applied voltages, wherein an excitation voltage deflects said mirror in a preferential tilt direction determined by a preferential set;

a detector for detecting light reflected from the micromirror device; and

a feedback circuit for receiving input from the detector and for controlling the excitation voltage to the micromirror device.

8. The light modulating unit of claim 7, wherein said preferential tilt direction is controlled by a residual hinge torque.

9. A device comprising:

an array of tiltable members supported by a substrate, each said tiltable member designed to deflect from an unenergized position in at least two directions,

a hinge associated with each said tiltable mirror, said hinge formed in a first position and substantially held in a deformed position until acquiring a preferential set, said preferential set being a deviation from said first position in the absence of external forces or applied voltages to provide said tiltable members a predetermined preferential tilt direction; and

bias structures capable of creating an electrostatic field to deflect said tiltable members.

10. The device of claim 9, wherein all said hinges have the same preferential tilt direction.

11. The device of claim 9, wherein groups of said hinges have a common preferential tilt direction.

12. The device of claim 9, wherein said preferential tilt direction is controlled by a residual hinge torque.