Spatial light modulator with superstructure light shield

• US 5,719,695 A
• Filed: 12/05/1996
• Issued: 02/17/1998
• Est. Priority Date: 03/31/1995
• Status: Expired due to Fees

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Heimbuch, Scott D.
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): BEY, DAWN MARIE
• Application Number:
  US08/761,022
• Time in Patent Office: 439 Days
• Field of Search: 359/291, 359/290, 359/223, 359/224, 359/846, 359/849, 359/851
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A high contrast spatial light modulator (40) formed of micro-mechanical pixels (10). The supporting superstructure comprising the posts (12) and hinges (16) of the pixels (10) are shielded by an umbrella-like elevated light shield (42) extending over the hinge and posts. These light shields (42) are generally square in shape, and have edges arranged at approximately 45° with respect to the incident light to minimize diffraction of light therefrom into projection optics. The upper surfaces of the shields may be anodized to achieve a non-reflective, black surface when viewed through darkfield optics. The shields (42) are fabricated using conventional semiconductor processes, which are a natural extension of the baseline process.

Claims

1. A spatial light modulator, comprising;

a) a substrate;

b) addressing circuitry formed on said substrate;

c) a support structure fixedly formed upon said substrate;

d) an array of deflectable pixels supported by said fixed support structure over said addressing circuitry; and

e) shield means fabricated upon and over said fixed support structure for shielding said support structure associated with at least two adjacent said pixels from incident light illuminating said spatial light modulator said shield means having a light absorbing upper surface.

2. The spatial light modulator as specified in claim 1 wherein said shield means comprises at least one elevated shield member fabricated above said support structure.

3. The spatial light modulator as specified in claim 2 wherein said shield member cantilevers over said support structure.

4. The spatial light modulator as specified in claim 3 where said shield member cantilevers 360°

about said support structure.

5. The spatial light modulator as specified in claim 2 wherein said support structure comprises a post fixed to said substrate and a hinge supported by and extending from said post to said pixel, wherein said shield member is fabricated over and separated from said hinge.

6. The spatial light modulator as specified in claim 1 wherein said pixels of said array are arranged in rows, wherein said shield member overlaps at least one said pixel in adjacent said rows.

7. The spatial light modulator as specified in claim 2 wherein said shields are flat and are substantially rectangular in shape.

8. The spatial light modulator as specified in claim 2 wherein said light absorbing upper surface is anodized.

9. The spatial light modulator as specified in claim 2 wherein said support structure, and said pixel are comprised of an electrically conductive material.

10. The spatial light modulator as specified in claim 9 wherein said addressing circuitry includes at least one address electrode, whereby a voltage potential applied across said address electrode and said pixel induces deflection of said associated pixel extending thereover.

11. The spatial light modulator as specified in claim 2 wherein said support structure comprises a pair of torsion hinges supporting said pixel along a central axis of rotation thereof.

12. The spatial light modulator as specified in claim 11 wherein said shield member has edges extending at approximately 45°

with respect to said central axis of rotation.

13. The spatial light modulator as specified in claim 11 wherein said shield member completely overlaps one said torsion hinge.