Yokeless hidden hinge digital micromirror device

• US 7,654,677 B2
• Filed: 08/06/2007
• Issued: 02/02/2010
• Est. Priority Date: 11/21/2001
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Oden, Patrick I., Mezenner, Rabah, Knipe, Richard L., DiCarlo, Anthony, Huffman, James D.
• Primary Examiner(s): Dowling; William C
• Application Number:
  US11/834,583
• Publication Number:
  US 20070285757A1
• Time in Patent Office: 911 Days
• Field of Search: 348/770, 348/771, 359290-292, 359/846, 359/849, 359/850, 359/872, 359/876, 359/318, 359/198, 359/212, 359/213, 359220-226, 359/295, 347/237, 353/98, 353/99
• US Class Current: 353/99
• CPC Class Codes: B81B 3/0035 Constitution or structural means for controlling the movement of the flexible or deformable elements
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10T 428/22 Nonparticulate element embedded or inlaid in substrate and visible

Abstract

A micromirror array 110 fabricated on a semiconductor substrate 11. The array 110 is comprised of three operating layers 12, 13, 14. An addressing layer 12 is fabricated on the substrate. A hinge layer 13 is spaced above the addressing layer 12 by an air gap. A mirror layer 14 is spaced over the hinge layer 13 by a second air gap. The hinge layer 13 has a hinge 13a under and attached to the mirror 14a, the hinge 13a permitting the mirror 14a to tilt. The hinge layer 13 further has spring tips 13c under the mirror 14a, which are attached to the addressing layer 12. These spring tips 13c provide a stationary landing surface for the mirror 14a.

Claims

1. A micromechanical device comprising:

a substrate;

a hinge member spaced apart from said substrate;

an electrode spaced apart from said substrate, said electrode comprising a lower portion and an upper portion spaced apart from said lower portion by a first distance, the upper portion spaced apart from said substrate by a second distance greater than the first distance; and

a contact point spaced apart from said substrate, wherein said upper portion is closer to said hinge member than said contact point is to said hinge member.

2. The micromechanical device of claim 1 comprising a moveable member operable to contact said contact point upon movement of said moveable member.

3. The micromechanical device of claim 1, said contact point and said hinge member formed from a common layer.

4. The micromechanical device of claim 1, said hinge member and said upper portion formed from a common layer.

5. The micromechanical device of claim 1, said upper portion and said contact point formed from a common layer.

6. The micromechanical device of claim 1, wherein said electrode is operable to attract said moveable member.

7. The micromechanical device of claim 1, wherein the moveable member is a micromirror.

8. The micromechanical device of claim 1, wherein the device is a micromirror array.

9. A method of forming a micromirror device, the method comprising:

providing a substrate;

forming a hinge member spaced apart from said substrate

forming a lower electrode portion spaced apart from said substrate;

forming an upper electrode portion spaced apart from said lower electrode portion by a first distance, the raised electrode also spaced apart from said substrate by a second distance greater than the first distance; and

forming a contact point spaced apart from said substrate, wherein said upper electrode portion is closer to said hinge member than said contact point is to said hinge member.

10. The method of claim 9 comprising forming a moveable member operable to contact said contact point upon movement of said moveable member.

11. The method of claim 9 comprising forming said contact point and said upper electrode portion from a common layer.

12. The method of claim 9 comprising forming said hinge member and said contact point from a common layer.

13. The method of claim 9 comprising forming said upper electrode portion and said hinge member from a common layer.

14. The method of claim 9 comprising forming said electrode operable to attract said moveable member.

15. The method of claim 9 wherein forming said moveable member comprises forming a micromirror.

16. A micromechanical device comprising:

a substrate;

an electrode having at least a portion spaced apart from said substrate;

a limit structure spaced apart from said substrate;

a hinge structure spaced apart from said substrate; and

a deflectable member connected to said hinge and operable to deflect about an axis, said deflection limited by contact with said limit structure, wherein a distance between said portion of said electrode and said axis is less than a distance between said limit structure and said axis.

17. The micromechanical device of claim 16, wherein said hinge structure, said portion, and said limit structure are formed from a common layer.

18. The micromechanical device of claim 16, wherein said hinge structure is spaced apart from said substrate by a distance equal to a distance between said portion and said substrate.

19. The micromechanical device of claim 16, wherein said hinge structure is spaced apart from said substrate by a distance equal to a distance between said limit structure and said substrate.

20. The micromechanical device of claim 16, wherein said portion is spaced apart from said substrate by a distance equal to a distance between said limit structure and said substrate.