Sunken electrode configuration for MEMs micromirror

• US 20050089266A1
• Filed: 09/21/2004
• Published: 04/28/2005
• Est. Priority Date: 05/28/2002
• Status: Active Grant

• Current Assignee: Lumentum Operations, LLC (Lumentum Holdings Inc.)
• Original Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Inventors: Miller, John Michael, Ma, Yuan, McKinnon, Graham
• Granted Patent: US 7,302,131 B2
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G02B 6/3518 the reflective optical element being an intrinsic part of a MEMS device, i.e. fabricated together with the MEMS device MEMS devices in general B81B; manufacture of MEM devices in general B81C; micromechanical devices controlling the direction of light G02B26/0833
• CPC Class Codes: G02B 6/356 in an optical cross-connect device, e.g. routing and switching aspects of interconnecting different paths propagating different wavelengths to (re)configure the various input and output links switching polarized beams G02B6/3594; power equalizers G02B6/356 and G02B6/3594; path selecting means H04Q11/0001
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/3584 constructional details of an associated actuator having a MEMS construction, i.e. constructed using semiconductor technology such as etching MEMS per se B81B, B81C
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A micro-electro-mechanical (MEMs) mirror device for use in an optical switch is disclosed. A “piano”-style MEMs device includes an elongated platform pivotally mounted proximate the middle thereof by a torsional hinge. The middle portion of the platform and the torsional hinge have a combined width less than the width of the rest of the platform, whereby several of these “piano” MEMs devices can be positioned adjacent each other pivotally mounted about the same axis with only a relatively small air gap therebetween. In a preferred embodiment of the present invention electrostatic charges, which build up on exposed dielectric surfaces causing the mirror'"'"'s angular position to drift over time, are minimized by positioning the hot and ground electrodes at different levels separated by a vertical surface, and placing the dielectric material on the vertical surface.

Claims

1. A micro-electro-mechanical device mounted on a substrate comprising:

a pivoting member pivotally mounted on said substrate about a first axis;

a first hot electrode beneath the pivoting member for pivoting the pivoting member about the first axis;

a first ground electrode adjacent to the first hot electrode separated by a step creating a vertical gap therebetween; and

a dielectric material in the gap for isolating the first hot electrode from the first ground electrode.

2. The device according to claim 1, wherein the first hot electrode is sunken relative to the first ground electrode.

3. The device according to claim 2, wherein the step is under cut beneath the first ground electrode.

4. The device according to claim 1, wherein the first hot electrode includes a trace electrode extending therefrom for connection with a power source;

and wherein the first ground electrode covers the trace electrode.

5. The device according to claim 1, wherein the pivoting member includes a first end proximate the first axes, and an outer free end remote from the first axes;

wherein the first hot electrode includes a first step beneath the first end, and a second step, lower than the first step, beneath the outer free end.

6. The device according to claim 1, wherein the pivoting member includes a first and a second supporting region on opposite sides of said first axis;

wherein the first electrode is beneath the first supporting region; and

further comprising a second electrode beneath the second supporting region for pivoting the pivoting member about the first axis.

7. The device according to claim 1, further comprising shields disposed on each side of said first electrode for limiting the amount of electrical cross-talk between adjacent pivoting members.

8. The device according to claim 7, wherein the shields extend downwardly from an undersurface of said pivoting member.

9. The device according to claim 7, wherein the shields extend upwardly from the substrate above a top surface of the first electrode, and downwardly from an undersurface of said pivoting member inside or outside of the upwardly extending shields.

10. A micro-electro-mechanical device mounted on a substrate comprising:

an array of pivoting members pivotally mounted on said substrate about a first axis;

a first hot electrode beneath each pivoting member for pivoting respective pivoting members about the first axis; and

a first ground electrode adjacent to each first hot electrode separated by a substantially vertical surface;

wherein the vertical surfaces comprises a dielectric surface for isolating the first hot electrodes from the first ground electrodes.

11. The device according to claim 10, wherein the first hot electrodes are sunken relative to the first ground electrodes.

12. The device according to claim 11, wherein each substantially vertical surface is under cut beneath each first ground electrode.

13. The device according to claim 10, wherein each first hot electrode includes a trace electrode extending therefrom for connection with a power source;

and wherein each first ground electrode covers a respective trace electrode.

14. The device according to claim 10, wherein each pivoting member includes a first end proximate the first axes, and an outer free end remote from the first axes;

wherein each first hot electrode includes a first step beneath the first end, and a second step, lower than the first step, beneath the outer free end.

15. The device according to claim 10, wherein each pivoting member includes a first and a second supporting region on opposite sides of said first axis;

wherein each first electrode is beneath respective first supporting region; and

further comprising a second electrode beneath each second supporting region for pivoting the pivoting members about the first axis.

16. The device according to claim 10, further comprising shields disposed on each side of said first electrodes for limiting the amount of electrical cross-talk between adjacent pivoting members.

17. The device according to claim 16, wherein the shields extend downwardly from an undersurface of each pivoting member.

18. The device according to claim 16, wherein the shields extend upwardly from the substrate above a top surface of each first electrode, and downwardly from an undersurface of each pivoting member inside or outside of the upwardly extending shields.

19. The device according to claim 16, wherein the first and second supporting regions include a reflective surface.

20. The device according to claim 19, further comprising reflective cusps extending from the substrate beneath a gap between the first and second supporting platforms of adjacent pivoting members for deflecting light traveling therebetween, whereby the light is not reflected straight back.