Digital optical switch apparatus and process for manufacturing same

• US 7,236,279 B2
• Filed: 10/18/2002
• Issued: 06/26/2007
• Est. Priority Date: 10/19/2001
• Status: Expired due to Term

• Current Assignee: Input/Output Incorporated
• Original Assignee: Input/Output Incorporated
• Inventors: Yu, Duli, Goldberg, Howard, Yi, Taechung, Selvakumar, Arjun
• Primary Examiner(s): Phan; James
• Application Number:
  US10/273,628
• Publication Number:
  US 20030118277A1
• Time in Patent Office: 1,712 Days
• Field of Search: 359198-199, 359/223, 359/224, 359/298, 359/872, 359/876, 310/309
• US Class Current: 359/225.1
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: B81C 2201/019 Bonding or gluing multiple substrate layers
• CPC Class Codes: G02B 2006/12104 Mirror; Reflectors or the like
• 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 6/3548 1xN switch, i.e. one input and a selectable single output of N possible outputs
• CPC Class Codes: G02B 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

The present invention provides a digital optical switch apparatus and process for manufacturing the apparatus. The apparatus includes a mirror assembly coupled to a top cap and to a bottom cap. The top and bottom caps each include one or more electrodes that, when energized with electrical energy, move a mirrored surface to one of a plurality of discrete positions. Mirror assemblies can be cascaded to create a packaged assembly having any multiple of discrete positions. The process includes planar micro-machining techniques to create isolated islands for electrical feed through. The process enables mechanical bonding of multiple tiers via a single bond region and through a bond-pad window.

Claims

1. A micro-machined device comprising:

a) a housing;

b) a support structure coupled to the housing;

c) a mass coupled to the support structure by a pair of single-gimbaled structures for providing rotational movement of the mass about first and second axes of rotation; and

d) a plurality of electrodes coupled to the housing in a diagonal relationship, one or more of the plurality of the electrodes capable of being energized with electrical power to provide a selectable force to the mass for moving the mass in one of a plurality of angular directions to a discrete stopping position for digital positioning of the mass to one of a plurality of digital switching positions.

2. The device of claim 1, wherein the single-gimbaled structures comprise T-shaped hinges.

3. The device of claim 1, wherein the housing comprises:

i) a bottom wafer;

ii) a middle wafer coupled to the bottom wafer; and

iii) a top wafer coupled to the middle wafer, the top wafer having a light-permitting window formed therein.

4. The device of claim 3, wherein the middle wafer includes the mass, the hinges and the support structure.

5. The device of claim 1, wherein the mass includes a mirrored surface adapted to reflect an incident light beam in any of the plurality of angular directions.

6. The device of claim 4, wherein the mass includes a mirrored surface adapted to reflect an incident light beam in any of the plurality of angular directions, the incident light beam entering through the light-permitting window.

7. The device of claim 6 further comprising an overlay coupled to the top wafer, the overlay including a plurality of ports for allowing light to pass through the overlay.

8. The device of claim 7, wherein the plurality of ports include at least one entry port for directing the incident light beam toward the mirrored surface and at least one exit port for directing the reflected light from the mirrored surface.

9. The device of claim 1, wherein the mass includes one or more portions contacting the housing during angular movement to stop the angular movement such that the mass stops angular movement in the discrete stopping position.

10. The device of claim 9, wherein the mass includes a mirrored surface adapted to reflect an incident light beam, the reflected light leaving the mirrored surface in a direction controlled by the angular position of the mirrored surface.

11. A micro-machined device for controllably directing a beam of light, the device comprising:

a) a mirror coupled to a support structure by a pair of single-gimbaled dual-axis hinges for providing rotational movement of the mass about first and second axes of rotation;

b) a top cap bonded to the mirror support structure and having therein a window to allow light to reach the mirror;

c) a bottom cap bonded to the mirror support structure;

d) a plurality of electrodes disposed on at least one of the top cap and the bottom cap, one or more of the plurality of the electrodes capable of being energized with electrical energy to provide a selectable force to the mirror for moving the mirror in a plurality of angular directions, the mirror including one or more portions contacting at least one of the top cap and the bottom cap during angular movement to stop movement of the mirror such that the mirror position is one of a plurality of discrete predetermined angular positions for digital positioning of the mirror to one of a plurality of digital switching positions.

12. The device of claim 11, wherein the plurality of electrodes comprises a first plurality of electrodes positioned on the top cap and a second plurality of electrodes positioned on the bottom cap.

13. The device of claim 11 further comprising an overlay coupled to the top cap, the overlay including a plurality of ports for allowing light to pass through the overlay.

14. The device of claim 13, wherein the plurality of ports include at least one entry port for directing the incident light beam toward the mirrored surface and at least one exit port for directing the reflected light from the mirrored surface.

15. The device of claim 11 further comprising a plurality of optic fibers for directing light into and from the device.

16. The device of claim 14, further comprising a plurality of optic fibers coupled to the ports for directing light.

17. The device of claim 11 further comprising a movement control structure disposed on the bottom cap to control movement of the mirror.

18. The device of claim 17, wherein the movement control structure is adapted to controllably damp movement of the mirror.

19. The device of claim 17, wherein the mirror contacts the movement control structure to reduce vertical mirror movement.

20. The device of claim 11, wherein the mirror further comprises a layer of material on a surface opposite the mirror surface, the material being selected to balance stress across the mirror to reduce mirror bowing.

21. A micro-machined device for controllably directing a beam of light, the device comprising a plurality of mirror assemblies, each mirror assembly comprising:

a) a mirror coupled to a support structure by a pair of single-gimbaled dual-axis hinges for providing rotational movement of the mass about first and second axes of rotation;

b) a top cap bonded to the mirror support structure and having therein a window to allow light to reach the mirror;

c) a bottom cap bonded to the mirror support structure; and

d) a plurality of electrodes disposed on at least one of the top cap and the bottom cap, the electrodes when energized with electrical energy provide a selectable force to the mirror for moving the mirror in a plurality of angular directions, the mirror including one or more portions contacting at least one of the top cap and the bottom cap during angular movement to stop movement of the mirror such that the mirror position is one of a plurality of discrete predetermined angular positions,

wherein light exiting a first mirror assembly is directed to enter a second mirror assembly.

22. The device of claim 21 further comprising a mirror fixed in relation to the first mirror assembly and the second mirror assembly to reflect light leaving the first mirror assembly toward the second mirror assembly.

23. The device of claim 21, wherein the first mirror assembly and the second mirror assembly are positioned substantially in a face-to-face relationship to allow light reflected from the first mirror assembly to enter the second mirror assembly.

24. The device of claim 21 further comprising a plurality of optic fibers coupled to the first mirror assembly and to the second mirror assembly for directing light leaving the first mirror assembly toward the second mirror assembly.