Electrical connections in microelectromechanical devices

• US 7,436,573 B2
• Filed: 07/13/2005
• Issued: 10/14/2008
• Est. Priority Date: 02/12/2003
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Duboc, Robert M. Jr., Patel, Satyadev R., Doan, Jonathan C.
• Primary Examiner(s): Sugarman; Scott J.
• Assistant Examiner(s): Pinkney; Dawayne A
• Application Number:
  US11/181,079
• Publication Number:
  US 20050250362A1
• Time in Patent Office: 1,189 Days
• Field of Search: 359290-292, 359223-225, 359/245, 359260-263, 359/298, 359/198, 359301-303, 359317-318, 359/237, 359/242, 359/295
• US Class Current: 359/291
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10T 29/49155 Manufacturing circuit on or in base

Abstract

A micromirror device and a method of making the same are disclosed herein. The micromirror device comprises a mirror plate, hinge, and post each having an electrically conductive layer. One of the hinge, mirror plate, and post further comprises an electrically insulating layer. To enable the electrical connections between the conducting layers of the hinge, mirror plate, and post, the insulating layer is patterned.

Claims

1. A micromirror array device, comprising:

a substrate;

a post on the substrate, the post comprising an electrically conductive post layer;

a deformable hinge held by the post on the substrate, the hinge comprising an electrically conductive hinge layer, wherein the electrically conductive hinge layer is electrically connected to the electrically conductive post layer of the post; and

a reflective and deflectable mirror plate attached to the deformable hinge such that the mirror plate is capable of rotating relative the substrate, said mirror plate comprising an electrically conductive mirror plate layer that is electrically connected to the electrically conductive hinge layer;

wherein at least one of the post, hinge or mirror plate further comprises an electrically insulating layer that is patterned so as to allow electrical connection to the electrically conductive layer of the another one of the post, hinge or mirror plate.

2. The device of claim 1, wherein the deformable hinge comprises the insulating layer.

3. The device of claim 2, wherein the insulating layer of the hinge is patterned differently than the conductive layer of the hinge.

4. The device of claim 3, wherein the insulating layer of the hinge comprises a contact area through which the conductive layers of the mirror plate and hinge are electrically connected.

5. The device of claim 2, wherein the hinge comprises another insulating layer;

and wherein the conductive layer of the hinge is laminated between the insulating layer and said another insulating layer of the hinge.

6. The device of claim 2, wherein the conductive layer of the hinge comprises TiN_x.

7. The device of claim 2, wherein the insulating layer of the hinge comprises SiN_x.

8. The device of claim 5, wherein said another insulating layer of the hinge comprises SiN_xX.

9. The device of claim 1, wherein the mirror plate comprises the insulating layer.

10. The device of claim 9, wherein the insulating layer of the mirror plate is patterned differently than the conductive layer of the mirror plate.

11. The device of claim 10, wherein the insulating layer of the hinge comprises a contact area through which the conductive layers of the mirror plate and hinge are electrically connected.

12. The device of claim 11, wherein the mirror plate comprises another insulating layer;

and wherein the conductive layer of the mirror plate is laminated between the insulating layer and said another insulating layer of the mirror plate.

13. The device of claim 9, wherein the conductive layer of the mirror plate comprises aluminum.

14. The device of claim 9, wherein the conductive layer of the mirror plate comprises titanium.

15. The device of claim 9, wherein the insulating layer of the mirror plate comprises SiO_x.

16. The device of claim 12, wherein said another insulating layer of the hinge comprises SiO_x.

17. The device of claim 1, wherein the post comprises the insulating layer.

18. The device of claim 17, wherein the insulating layer of the post is patterned differently than the conductive layer of the post.

19. The device of claim 18, wherein the insulating layer of the post comprises a contact area through which the conductive layers of the post and hinge are electrically connected.

20. The device of claim 19, wherein the conductive layer of the post comprises TiN_x.

21. The device of claim 19, wherein the insulating layer of the post comprises SiO_x.

22. The device of claim 1, wherein the substrate is transmissive to visible light.

23. The device of claim 22, further comprising:

a semiconductor substrate on which an addressing electrode is formed, said semiconductor substrate being disposed proximate to the light transmissive substrate such that the mirror plate is capable of being deflected an electrostatic filed between the mirror plate and the addressing electrode.

24. The device of claim 23, wherein the semiconductor substrate is bonded to the light transmissive substrate.

25. The device of claim 24, further comprising:

a substrate post comprising an electrically conductive material that is electrically connected to the conducting layer of the post, said substrate post being disposed between the two substrates.

26. The device of claim 25, wherein the substrate post is electrically connected to a contact pad on the semiconductor substrate.

27. The device of claim 26, wherein the semiconductor substrate is disposed on a package substrate;

and wherein the contact pad of the semiconductor substrate is wired to an electrical contact on the package substrate.

28. The device of claim 1, wherein the mirror plate is a member of an array of mirror plates.

29. The device of claim 28, wherein the conducting layers of the mirror plates are electrically connected.

30. A projection system, comprising:

an illumination system providing a light beam;

a spatial light modulator comprising an array of micromirrors of claim 1 for modulating the light beam from the illumination system; and

a projection lens for projecting the modulated light beam onto a display target.

31. The system of claim 30, wherein the illumination system comprises:

a light source producing light;

a lightpipe delivering the light onto the spatial light modulator; and

a color wheel disposed at a propagation path of the light, the color wheel comprising a set of color segments.

32. The system of claim 31, wherein the light source is an arc lamp.

33. The system of claim 31, wherein the light source is a LED.

34. The system of claim 32, wherein the illumination system comprises a LED.

35. The system of claim 34, wherein the LED produces a light that is red, green, or blue.

36. The system of claim 31, wherein the color wheel is disposed between the light source and lightpipe.

37. The system of claim 31, wherein the color wheel is disposed after both of the light source and lightpipe at the propagation path of the light.

38. The system of claim 32, wherein a color filter is absent from the display system.