Spatial light modulator having improved contrast ratio

• US 5,943,157 A
• Filed: 05/06/1998
• Issued: 08/24/1999
• Est. Priority Date: 05/08/1997
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Huffman, James D., Miller, Rodney D., Florence, James M.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US09/073,329
• Time in Patent Office: 475 Days
• Field of Search: 359/290, 359/291, 359/295, 359/223, 359/224, 359/226, 359/846, 359/850
• US Class Current: 359/290
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A spatial light modulator (70) comprised of an array of micromirrors (72) each having support post (74). The support post (74) defines support post edges (76) in the upper surface of the mirrors (72). These support post edges (76) are all oriented at 45 degree angles with respect to an incident beam of light from a light source (80) to minimize diffraction of light from the edges (76) into the darkfield optics when the mirrors are oriented in the off-state. The present invention achieves an increased contrast ratio of about 20% over conventional designs.

Claims

1. A spatial light modulator, comprising:

a support structure including a deflectable yoke;

means for deflecting said yoke; and

a pixel elevated above and supported by said yoke, said pixel having a light modulation surface defining surface edges and a support member extending between said surface and said yoke, said support member defining support edges in said surface, wherein said support edges are parallel to surface edges.

2. The spatial light modulator as specified in claim 1 wherein said surface edges and said support edges both define a rectangle.

3. The spatial light modulator as specified in claim 1 wherein said support member is centrally located with respect to said light modulation surface.

4. The spatial light modulator as specified in claim 3 wherein said support member extends perpendicular from said light modulation surface.

5. The spatial light modulator as specified in claim 1 further comprising a light source generating light beam incident to said light modulation surface defining an angle of incidence, said surface edges and said support edges both extending 45 degrees with respect to said angle of incidence.

6. The spatial light modulator as specified in claim 1 wherein said support edges define an area no greater than 5.76 mm².

7. A display system, comprising:

a light source generating a light beam;

a support structure including a yoke;

means for deflecting said yoke; and

a pixel elevated above and supported by said yoke, said pixel having a light modulation surface defining surface edges and having a support member extending between said surface and said yoke, said support member defining support edges in said surface, wherein said light beam is incident to said light modulation surface and generates an angle of incidence with respect thereto, said angle of incidence being 45 degrees with respect to both said support edges and said surface edges.

8. The spatial light modulator as specified in claim 7 wherein said surface edges and said support edges both define a rectangle.

9. The spatial light modulator as specified in claim 7 wherein said support member is centrally located with respect to said light modulation surface.

10. The spatial light modulator as specified in claim 7 wherein said support member extends perpendicular from said light modulation surface.

11. The spatial light modulator as specified in claim 7 wherein said support edges define an area no greater than 5.76 mm².