Micromirror and post arrangements on substrates

• US 7,042,622 B2
• Filed: 10/30/2003
• Issued: 05/09/2006
• Est. Priority Date: 10/30/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Reflectivity, Inc. (Texas Instruments, Inc.)
• Inventors: Huibers, Andrew, Patel, Satyadev
• Primary Examiner(s): Mack, Ricky
• Assistant Examiner(s): Dinh, Jack
• Application Number:
  US10/698,563
• Publication Number:
  US 20050094240A1
• Time in Patent Office: 922 Days
• Field of Search: 359290-292, 359/295, 359/298
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micromirror of a micromirror array of a spatial light modulator used in display systems comprises a mirror plate attached to a hinge that is supported by two posts formed on a substrate. Also the mirror plate is operable to rotate along a rotation axis that is parallel to but offset from a diagonal of the mirror plate when viewed from the top. An imaginary line connecting the two posts is not parallel to either diagonal of the mirror plate.

Claims

1. A spatial light modulator comprising:

an array of micromirrors, each micromirror comprising a mirror plate having four predominant sides and being held on a substrate by a plurality of posts, wherein the four predominant sides define two diagonals, and wherein a line between any two of the plurality of posts is not coincident with either of the two diagonals;

wherein the mirror plate is attached to a hinge that is supported by a post of the plurality of posts on the substrate; and

wherein the mirror plate and hinge are separated by a gap in a direction perpendicular to the mirror plate when the mirror plate is parallel to the substrate, wherein the substrate has four predominant sides that form a rectangular shape; and

wherein each side of the mirror plate is at an angle of from 5°

degrees to 25°

degrees to the two sides of the rectangular substrate.

2. The spatial light modulator of claim 1, wherein each mirror plate is in a shape of a rectangle, square, trapezoid or rhombus.

3. The spatial light modulator of claim 2, wherein the mirror plate is in a shape of square.

4. The spatial light modulator of claim 1, wherein the plurality of posts consists of two posts.

5. The spatial light modulator of claim 1, wherein the substrate has four predominant sides that form a rectangular shape;

and wherein each side of the mirror plate is at an angle of from 10°

degrees to 20°

degrees to the two sides of the rectangular substrate.

6. The spatial light modulator of claim 1, wherein the mirror plate is attached to the hinge such that the mirror plate is capable of rotating along a rotation axis that is parallel to but offset from a diagonal of the mirror plate when viewed from the top of the substrate.

7. The spatial light modulator of claim 6, wherein the micromirror further comprises:

an electrode placed proximate to the mirror plate such that a first electrical field is established between the first electrode and the mirror plate, and the mirror plate rotates relative to the substrate in a first rotation direction in response to the first electrical field.

8. The spatial light modulator of claim 7, wherein said electrode is a first electrode, and wherein the micromirror further comprises:

a second electrode placed proximate to the mirror plate such that a second electrical field is established between the second electrode and the mirror plate, and the mirror plate rotates relative to the substrate in a second rotation direction in response to the first electrical field, wherein the second rotation direction is opposite to the first rotation direction.

9. The spatial light modulator of claim 8, wherein the first and the second electrode are on a substrate other than the substrate to which the hinge support is connected.

10. The spatial light modulator of claim 8, wherein the first electrode is on a substrate other than the substrate to which the hinge support is connected;

and wherein the second electrode is on the substrate to which the hinge support is connected.

11. The spatial light modulator of claim 10, wherein the second electrode is an electrode film on a surface of the substrate to which the hinge support is connected.

12. The spatial light modulator of claim 6, wherein the micromirror further comprises;

an extension plate connected to the mirror plate.

13. The spatial light modulator of claim 12, wherein the extension plate is connected to the mirror plate via an extension plate post and the extension plate defines a gap between the extension plate and the mirror plate.

14. The spatial light modulator of claim 13, wherein said gap between the extension plate and the mirror plate is a first gap;

and wherein the extension plate is extended beyond the mirror plate and connected to the mirror plate via an extension-plate post; and

wherein the extension plate defines a second gap between the extension plate and the substrate to which the hinge support is connected.

15. The spatial light modulator of claim 12, wherein the extension plate is electrically conducting.

16. The spatial light modulator of claim 12, wherein the extension plate is dielectric with a dielectric constant larger than 1.0.

17. The spatial light modulator of claim 6, wherein the micromirror further comprises:

stop for stopping the rotation of the mirror plate when the mirror plate rotates to an ON state angle.

18. The spatial light modulator of claim 17, wherein the stop is disposed on the hinge support.

19. The spatial light modulator of claim 6, wherein the micromirror further comprises:

a stop for stopping the rotation of the mirror plate when the mirror plate rotates to an OFF state.

20. The spatial light modulator of claim 19, wherein the stop is disposed on the hinge support.

21. The spatial light modulator of claim 1, wherein the substrate has an anti-reflection film on a surface of the substrate.