MEMS optical switch with torsional hinge and method of fabrication thereof

• US 6,556,741 B1
• Filed: 10/25/2000
• Issued: 04/29/2003
• Est. Priority Date: 10/25/2000
• Status: Expired due to Fees

• Current Assignee: Crossfiber Inc., Optical Micro-Machines, Inc.
• Original Assignee: Omx Incorporated (Office Depot LLC)
• Inventors: Fan, Li
• Primary Examiner(s): Ullah, Akm E.
• Assistant Examiner(s): Rahll, Jerry T
• Application Number:
  US09/697,762
• Time in Patent Office: 916 Days
• Field of Search: 385/18, 359/872, 359/874
• US Class Current: 385/18
• CPC Class Codes: B81B 3/0062 Devices moving in two or more dimensions, i.e. having special features which allow movement in more than one dimension
• 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 6/357 Electrostatic force electrostatic forces controlling reflecting elements in general G02B26/0841
• CPC Class Codes: G02B 6/358 Latching of the moving element, i.e. maintaining or holding the moving element in place once operation has been performed; includes a mechanically bistable system
• 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

Abstract

In at least one embodiment, an apparatus having a first structure, a second structure, and a hinge coupled between the first and second structures. The hinge has a first flexible member aligned substantially along an axis. The hinge is arranged so that the second structure can rotate relative to the first structure substantially about the axis. The hinge can also include a second flexible member aligned substantially along the axis. The first and second flexible members being positioned on opposite sides of the second structure. In at least one embodiment, a method includes steps of fabrication of the apparatus.

Claims

1. A thin film structure comprising:

a first structure;

a second structure;

a hinge coupled between the first structure and the second structure, wherein the hinge has a first flexible member aligned substantially along an single axis, wherein the second structure can rotate relative to the first structure substantially about the axis;

wherein the hinge further comprises a second flexible member aligned substantially along the axis;

wherein the first flexible member and the second flexible member are positioned on opposite sides of the second structure;

wherein the hinge further comprises a central section positioned between the first flexible member and second flexible member and connected to the second structure;

wherein the first flexible member and the second flexible member are both deformable about the axis;

wherein the first flexible member and the second flexible member both deform about the axis as the second structure is rotated;

wherein the first flexible member and the second flexible member are elongated;

wherein the hinge further comprises a first anchor mounted between the first structure and the first flexible member and a second anchor mounted between the first structure and the second flexible member, so that the first anchor and the second anchor couple the hinge to the first structure;

wherein the first anchor extends away from the first structure to the first flexible member, so that an opening is defined between the first flexible member and the first structure, and wherein the second anchor extends away from the first structure to the second flexible member, so that an opening is defined between the second flexible member and the first structure;

wherein the first and second flexible members exert a biasing force on the second structure to urge the second structure towards the first structure; and

wherein the hinge further comprises a tab connecting the central section to the second structure, so that the tab couples the hinge to the second structure.

2. The thin film structure of claim 1, wherein the central section is an elongated member substantially aligned with the axis.

3. The thin film structure of claim 2, wherein the second structure is a mirror structure.

4. The thin film structure of claim 3, wherein the first structure is an actuator arm.

5. The thin film structure of claim 2, wherein the second structure is a latch.

6. The thin film structure of claim 2, wherein the first structure is an actuator arm.

7. The thin film structure of claim 6, wherein the first structure is a main arm.

8. The thin film structure of claim 6, wherein the first structure is a backflap.

9. The thin film structure of claim 2, wherein the second structure is an actuator arm.

10. The thin film structure of claim 9, wherein the first structure is a substrate.

11. The thin film structure of claim 10, where in the actuator arm has a mirror for reflecting a light beam.

12. The thin film structure of claim 10, wherein the actuator arm comprises a main arm, a backflap, and a mirror structure, wherein the mirror is mounted on the mirror structure.

13. The thin film structure of claim 9, wherein the actuator arm is comprised of a polycrystalline silicon.

14. The thin film structure of claim 13, wherein the actuator arm is about 1.0 μ

m thick.

15. The thin film structure of claim 9, wherein the first structure is comprised of polycrystalline silicon.

16. The thin film structure of claim 15, wherein the first structure is about 0.5 μ

m thick.

17. The thin film structure of claim 1, wherein the hinge is comprised of polycrystalline silicon.

18. The thin film structure of claim 17, wherein the hinge is about 1.0 μ

m thick.

19. A MEMS optical switch comprising:

a substrate surface;

an actuator arm having a mirror; and

a hinge mounted between the substrate surface and the actuator arm so that the actuator arm can rotate relative to the substrate surface, wherein the hinge comprises;

central section, wherein the central section is mounted to the actuator arm;

a first flexible member;

a second flexible member, wherein the first flexible member and the second flexible members are connected to opposing sides of the central section substantially along an axis;

a first anchor, wherein the first anchor is mounted between the first flexible member and the substrate surface; and

a second anchor, wherein the second anchor is mounted between the second flexible member and the substrate surface;

wherein the first flexible member and the second flexible member both deform about the axis as the actuator arm is rotated;

wherein the first flexible member and the second flexible member are elongated beams;

wherein the first anchor extends away from the substrate surface to the first flexible member, so that an opening is defined between the first flexible member and the substrate surface, and wherein the second anchor extends away from the substrate surface to the second flexible member, so that an opening is defined between the second flexible member and the substrate surface;

wherein the opening extends under the central section;

wherein the first and second flexible members exert a biasing force on the actuator arm to urge the actuator arm towards the substrate surface;

wherein the hinge further comprises a tab connecting the central section to the actuator arm.

20. The MEMS optical switch of claim 19, wherein the actuator arm comprises a backflap and a main arm, wherein the backflap and the main arm are disposed on opposing sides of the hinge, lateral to the axis.

21. The MEMS optical switch of claim 20, wherein the hinge further comprises a main arm connector positioned between the central section and the main arm and a backflap connector positioned between the backflap and the central section.

22. The MEMS optical switch of claim 21, wherein the main arm connector comprises two tabs and wherein the backflap connector comprises two tabs.

23. The MEMS optical switch of claim 22, wherein the central section is an elongated member substantially aligned with the axis.

24. The MEMS optical switch of claim 23, wherein the hinge is comprised of a polycrystalline silicon.

25. The MEMS optical switch of claim 24, wherein the hinge is about 1.0 μ

m thick.

26. The MEMS optical switch of claim 25, wherein the actuator arm is comprised of a polycrystalline silicon.

27. The MEMS optical switch of claim 26, wherein the actuator arm is about 1.0 μ

m thick.

28. The MEMS optical switch of claim 27, wherein the substrate surface comprised of a polycrystalline silicon.

29. The MEMS optical switch of claim 28, wherein the substrate surface is about 0.5 μ

m thick.

30. A thin film structure comprising:

a first structure;

a second structure; and

a hinge coupled between the first structure and the second structure, wherein the hinge comprises a first flexible member;

a center section coupled to the first flexible member;

a second flexible member coupled to the center section, the first flexible member, second flexible member and center portion aligned substantially along a single axis; and

a tab connecting the second structure to the center section.

31. A MEMS optical switch comprising:

a. a substrate surface;

b. an actuator arm having a mirror; and

c. a hinge mounted between the substrate surface and the actuator arm so that the actuator arm can rotate relative to the substrate surface, wherein the hinge comprises;

(i) a central section, wherein the central section is mounted to the actuator arm via a tab;

(ii) a first flexible member;

(iii) a second flexible member, wherein the first flexible member and the second flexible members are connected to opposing sides of the central section substantially along an axis;

(iv) a first anchor, wherein the first anchor is mounted between the first flexible member and the substrate surface; and

(v) a second anchor, wherein the second anchor is mounted between the second flexible member and the substrate surface.