Electro-optical package with drop-in aperture

• US 20020056900A1
• Filed: 11/09/2001
• Published: 05/16/2002
• Est. Priority Date: 11/16/2000
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Kocian, Thomas A., Liu, Jwei Wien
• Granted Patent: US 6,762,868 B2
• Time in Patent Office: Days
• US Class Current: 257/687
• CPC Class Codes: B81B 7/0067 for controlling the passage of optical signals through the package
• CPC Class Codes: H01L 23/552 Protection against radiation, e.g. light or electromagnetic waves
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A drop-in aperture 20, which improves the performance and lowers the cost of electro-optical SLM packages. The disclosed package provides a separate metal light shield (aperture) 20 and antireflective coated cover 33, and positions the aperture 20 inside the package 40 in close proximity to the SLM'"'"'s 41 surface. This approach further uses an on-chip SLM light shield to define the projected screen border, thereby making the edge definition of the metal drop-in aperture less critical. Therefore, the cover can be mounted well away from the plane of the SLM, which relaxes the defect requirements of the cover and lowers the cost of the overall package. The package of this invention improves the performance and lifetime and lowers the cost of projection display systems. The preceding abstract is submitted with the understanding that it only will be used to assist in determining, from a cursory inspection, the nature and gist of the technical disclosure as described in 37 C.F.R. § 1.72(b). In no case should this abstract be used for interpreting the scope of any patent claims.

Claims

1. A spatial light modulator package with drop-in aperture, comprising:

a substrate;

a case molded to said substrate and defining a package cavity;

a spatial light modulator in said cavity;

an optically clear top cover supported by said substrate to enclose said spatial light modulator; and

a drop-in aperture between said cover and said spatial light modulator.

2. The spatial light modulator package of claim 1, wherein said aperture is stamped metal.

3. The spatial light modulator package of claim 1, wherein:

said aperture is separate from said cover glass; and

said aperture is mounted on a surface inside said package cavity and in close proximity to said spatial light modulator.

4. The spatial light modulator package of claim 1, wherein said aperture prevents stray light from reaching surfaces around perimeter of said spatial light modulator.

5. The spatial light modulator package of claim 1, further comprising:

a built-in light shield fabricated on the surface of said spatial light modulator chip.

6. The spatial light modulator package of claim 1, wherein said cover is mounted out of the plane of the spatial light modulator.

7. The spatial light modulator package of claim 1, said cover having an anti-reflective coating.

8. The spatial light modulator package of claim 1, said spatial light modulator being a micromirror.

9. The spatial light modulator package of claim 1, further comprising:

an environmental control material carrier in said cavity; and

getters held by said carrier.

10. The spatial light modulator package of claim 9, wherein said getters are comprised of moisture collecting desiccants.

11. The spatial light modulator package of claim 10 wherein said aperture and carrier are combined.

13. The projection display of claim 12 wherein:

said spatial light modulator array is a micromirror array; and

said aperture is mounted in close proximity to said micromirror array to limit the light reaching the area surrounding said micromirror array; and

said cover glass is mounted out of the plane of said micromirror array.

14. The micromirror projection display of claim 12 further comprising at least one environmental control material carrier.

15. The micromirror projection display of claim 14 wherein said environmental control material carrier holds at least one environmental control material selected from the group consisting of:

moisture collecting desiccants and lubricant storage reservoirs.

16. The micromirror projection display of claim 15 wherein said desiccants collect moisture in said micromirror package.

12. A projection display comprising:

a light source for producing a beam of light;

a first condenser lens for focusing said beam of light;

a color filter wheel for filtering said focused beam of light;

a second condenser lens for focusing said filtered beam of light;

a spatial light modulator array mounted in a package with a drop-in aperture and window for spatially modulating said beam of light; and

a projection lens for focusing said spatially modulated beam of light on an image plane.