Active yoke hidden hinge digital micromirror device

• US 5,535,047 A
• Filed: 04/18/1995
• Issued: 07/09/1996
• Est. Priority Date: 04/18/1995
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Hornbeck, Larry J.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US08/424,021
• Time in Patent Office: 448 Days
• Field of Search: 359/219, 359/295, 359/292, 359/224, 359/214, 359/290, 359/230, 359/223, 359/846
• US Class Current: 359/295
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A spatial light modulator (10) of the DMD type having increased performance parameters. A pixel mirror (30) is supported by a yoke (32), whereby electrostatic attraction forces (70, 76, 80, 82) are generated between several structures. First, between the elevated mirror (30) and an elevated address electrode (50, 52). Second, between the yoke (32) and an underlying address electrode (26, 28). The pixel (30) achieves high address torque, high latching torques, high reset forces, and greater address margins over previous generation devices. The proximity of the yoke (32) over the substrate address electrodes (26, 28) realizes large attraction forces whereby the pixel is less susceptible to address upset, requires lower reset voltages and provides higher switching speeds.

Claims

1. A spatial light modulator, comprising:

a) a substrate;

b) addressing circuitry comprising a first portion provided proximate said substrate and a second portion elevated above said substrate;

c) a yoke supported over said addressing circuitry first portion;

d) at least one hinge connected to said yoke and supporting said yoke, said hinge permitting deflection of said yoke; and

e) a pixel elevated above and supported by said yoke, said pixel positioned over said elevated addressing circuitry second portion.

2. The spatial light modulator as specified in claim 1 comprising a pair of said hinges axially supporting said yoke along a yoke axis, wherein said addressing circuitry first portion is provided each side of said yoke axis.

3. The spatial light modulator as specified in claim 2 wherein said yoke has a pair of yoke tips on each side of said yoke axis.

4. The spatial light modulator as specified in claim 3 wherein said yoke has a butterfly shape.

5. The spatial light modulator as specified in claim 2 wherein a first pair of opposing surface areas are defined between said yoke and said addressing circuitry first portion, and a second pair of opposing surface areas are defined between said pixel and said addressing circuitry second portion, said second pair of opposing surface areas being laterally defined a greater distance from said yoke axis than is said first pair of opposing surface areas from said yoke axis.

6. The spatial light modulator as specified in claim 2 further comprising control circuitry coupled to said addressing circuitry, said control circuitry providing address data to one of said addressing circuitry first portions to cause deflection of said yoke toward said addressed first portion.

7. The spatial light modulator as specified in claim 1 wherein said yoke has a width less than the width of said pixel and said pixel overlaps said yoke.

8. The spatial light modulator as specified in claim 1 wherein a first spacing is defined between said yoke and said addressing circuitry first portion, and a second spacing is defined between said pixel and said addressing circuitry second portion, wherein said first spacing is smaller than said second spacing.

9. The spatial light modulator as specified in claim 1 wherein said yoke is in substantially the same plane as said addressing circuitry second portion.

10. The spatial light modulator as specified in claim 1 further comprising a bias/reset bus constructed on said substrate and electrically connected to said pixel.

11. The spatial light modulator as specified in claim 1 wherein said hinge is in substantially the same plane as said yoke.

12. The spatial light modulator as specified in claim 1 further comprising control circuitry coupled to said addressing circuitry, said control circuitry providing address data to said addressing circuitry first portion and said second portion to cause deflection of said pixel.

13. The spatial light modulator as specified in claim 1 further comprising a support post connected to and supporting said hinge.

14. The spatial light modulator as specified in claim 1 wherein said addressing circuitry first portion and said second portion are electronically connected to one another.

15. The spatial light modulator as specified in claim 1 wherein said pixel is a mirror.

16. The spatial light modulator as specified in claim 15 wherein said mirror has a rectangular shape.

17. The spatial light modulator as specified in claim 16 wherein said mirror has edges geometrically oriented at 45°

with respect to said hinge.

18. A spatial light modulator, comprising:

a) a substrate;

b) addressing circuitry comprising a first portion provided proximate said substrate and a second portion residing above a plane defined by said first portion;

c) a yoke supported over said addressing circuitry first portion;

d) at least one hinge connected to said yoke and supporting said yoke, said hinge permitting deflection of said yoke; and

e) a pixel elevated above and supported by said yoke, said pixel positioned over said elevated addressing circuitry second portion.