Split beam micromirror

• US 20030123126A1
• Filed: 12/30/2002
• Published: 07/03/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Mangrum, Brett A., Meyer, Thomas J., Shih, Wei-Yan, Huffman, James D., Mignardi, Michael A., Reed, Mark F.
• Granted Patent: US 7,106,491 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A system and method of providing a micromirror pixel 400 that is highly resistant to bright failure states. The micromirror 400 uses an asymmetric yoke 402 to ensure the mirror is only attracted to the address electrode in one rotation direction. The landing mechanism on the other side of the torsion binge axis also is altered to allow the pixel to over rotate in the “off” direction. The over rotation ensures that light reflected by the mirror when in the off direction will miss the projection lens pupil, allowing the corresponding pixel to remain dark in both an operational and failed state.

Claims

1. A micromirror device comprising:

a substrate;

at least one address electrode supported by said substrate;

a torsion hinge supported apart from said substrate;

an asymmetric yoke supported by said torsion hinge; and

a deflectable member supported by and apart from said yoke.

2. The micromirror device of claim 1, said asymmetric yoke limiting deflection of said deflectable member in a first direction of rotation about said torsion hinge and not so limiting said deflection in an opposite direction.

3. The micromirror of claim 1, said at least one address electrode comprising:

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said asymmetric yoke only toward said one side of said torsion hinge axis.

5. The micromirror of claim 1, said at least one address electrode comprising:

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said asymmetric yoke only toward said one side of said torsion hinge axis.

4. A micromirror device comprising:

a substrate;

at least one address electrode supported by said substrate;

a torsion hinge supported apart from said substrate;

a yoke supported by said torsion hinge; and

a deflectable member supported by and apart from said yoke, said yoke limiting deflection of said deflectable member in a first direction of rotation about said torsion hinge and not so limiting said deflection in an opposite direction.

6. A micromirror device comprising:

a substrate;

a torsion hinge supported apart from said substrate;

a yoke supported by said torsion hinge;

a deflectable member supported by and apart from said yoke; and

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said yoke only toward said one side of said torsion hinge axis.

7. A micromirror device comprising:

a substrate;

a torsion hinge supported apart from said substrate;

a deflectable member supported by and apart from said torsion hinge;

a means for rotating said deflectable member about said torsion hinge; and

a means for limiting said deflection of said deflectable member in a first direction to a greater degree than in a second direction.

8. The micromirror device of claim 7, said means for limiting said deflection comprising an asymmetric yoke.

9. The micromirror device of claim 7, said means for limiting said deflection comprising a least one landing nub.

10. A display system comprising:

a light source for providing a beam of light along a light path;

a micromirror on said light path for selectively modulating said beam of light, said micromirror comprising;

a substrate;

at least one address electrode supported by said substrate;

a torsion hinge supported apart from said substrate;

an asymmetric yoke supported by said torsion hinge; and

a deflectable member supported by and apart from said yoke; and

a projection lens for focusing said selectively modulated beam of light.

11. The display system of claim 10, said asymmetric yoke limiting deflection of said deflectable member in a first direction of rotation about said torsion hinge and not so limiting said deflection in an opposite direction.

12. The display system of claim 10, said at least one address electrode comprising:

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said asymmetric yoke only toward said one side of said torsion hinge axis.

13. A display system comprising:

a light source for providing a beam of light along a light path;

a micromirror on said light path for selectively modulating said beam of light, said micromirror comprising;

a substrate;

at least one address electrode supported by said substrate;

a torsion hinge supported apart from said substrate;

a yoke supported by said torsion hinge; and

a deflectable member supported by and apart from said yoke, said yoke limiting deflection of said deflectable member in a first direction of rotation about said torsion hinge and not so limiting said deflection in an opposite direction; and

a projection lens for focusing said selectively modulated beam of light.

14. The display system of claim 13, said at least one address electrode comprising:

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said asymmetric yoke only toward said one side of said torsion hinge axis.

15. A display system comprising:

a light source for providing a beam of light along a light path;

a micromirror on said light path for selectively modulating said beam of light, said micromirror comprising;

a substrate;

a torsion hinge supported apart from said substrate;

a yoke supported by said torsion hinge;

a deflectable member supported by and apart from said yoke; and

an address electrode supported by said substrate on one side of an axis of said torsion hinge, said address electrode operable to attract said yoke only toward said one side of said torsion hinge axis; and

a projection lens for focusing said selectively modulated beam of light.

16. A display system comprising:

a light source for providing a beam of light along a light path;

a micromirror on said light path for selectively modulating said beam of light, said micromirror comprising;

a substrate;

a torsion hinge supported apart from said substrate;

a deflectable member supported by and apart from said torsion hinge;

a means for rotating said deflectable member about said torsion hinge; and

a means for limiting said deflection of said deflectable member in a first direction to a greater degree than in a second direction; and

a projection lens for focusing said selectively modulated beam of light.

17. The display system of claim 16, said means for limiting said deflection comprising an asymmetric yoke.

18. The display system of claim 16, said means for limiting said deflection comprising a least one landing nub.