MEMS G-switch device

• US 7,999,201 B2
• Filed: 11/06/2008
• Issued: 08/16/2011
• Est. Priority Date: 11/06/2008
• Status: Active Grant

• Current Assignee: Shandong Gettop Acoustic Company Limited (Weifang Gaoke Electronic Company Limited)
• Original Assignee: Shandong Gettop Acoustic Company Limited (Weifang Gaoke Electronic Company Limited)
• Inventors: Cao, Xin Ping, Zhe, Wang
• Primary Examiner(s): Friedhofer; Michael A
• Application Number:
  US12/291,106
• Publication Number:
  US 20100108478A1
• Time in Patent Office: 1,013 Days
• Field of Search: 200 6145 R- 6145 M, 735/140.1, 735/140.2, 7351416-51418, 735/142.3, 735/142.4, 735/143.5, 735/143.8
• US Class Current: 200/61.45R
• CPC Class Codes: G01P 15/08 with conversion into electric or magnetic values
• CPC Class Codes: G01P 15/135 by making use of contacts which are actuated by a movable inertial mass
• CPC Class Codes: H01H 1/0036 Switches making use of microelectromechanical systems [MEMS] for electromagnetic relays H01H50/005; for electrostatic relays H01H59/0009
• CPC Class Codes: H01H 35/14 Switches operated by change of acceleration, e.g. by shock or vibration, inertia switch wherein the liquid constitutes a contact of the switch H01H29/002

Abstract

A Micro Electro Mechanical Systems (MEMS) G-switch includes one or more actuators formed between fixed driving stages and moveable driving stages. A proof mass is attached to the moveable driving stages and flexibly attached to a substrate through one or more spring members. A voltage control circuit applies working voltages to the driving stages. With a first working voltage applied between the moveable and the fixed driving stages, moving of the driving stages'"'"' sensing direction towards gravity at a first critical angle will cause moveable driving stages to collapse and touch the fixed driving stage on the substrate and thus turn on the MEMS G-switch. After turning on the G-switch, a second working voltage is applied and moving of the driving stages'"'"' sensing direction away from gravity at a second critical angle will cause moveable electrodes to deviate from the fixed electrodes and thus turn off the MEMS G-switch.

Claims

1. A MEMS G-switch comprising:

a silicon substrate;

a proof mass;

one or more moveable driving stages attached to said proof mass;

a plurality of mechanical springs each having one end attached to said substrate and another end attached to said one or more moveable driving stages;

one or more fixed driving stages attached to said substrate;

bumps attached on said moveable driving stages or said fixed driving stages; and

a voltage control circuit applying voltage between said moveable driving stages and said fixed driving stages wherein said G-switch is turned off when it is in an orientation perpendicular to the direction of gravity and said one or more moveable driving stages deviate from said one or more fixed driving stages, and wherein said G-switch is turned on when it is in an orientation parallel to the direction of gravity and the gravity force of said proof mass pulls said one or more moveable driving stages to collapse onto said one or more fixed driving stages.

2. The MEMS G-switch according to claim 1, wherein said proof mass is suspended onto said substrate by said plurality of mechanical springs.

3. The MEMS G-switch according to claim 1, wherein said one or more moveable driving stages comprise driving electrodes which are connected to said voltage control circuit.

4. The MEMS G-switch according to claim 1, wherein said substrate acts as said one or more fixed driving stages and wherein said bumps are on a bottom surface of said one or more moveable driving stages over a top surface of said substrate.

5. The MEMS G-switch according to claim 2, wherein each of said plurality of mechanical springs have one end connected to said one or more moveable driving stages and another end connected to a plurality of anchors on said substrate.

6. The MEMS G-switch according to claim 1, wherein when said MEMS G-switch is turned off, a first working voltage is applied to said one or more moveable driving stages and the electrostatic force generated from said first working voltage and the gravity force of said proof mass pulls said one or more moveable driving stages to collapse onto said one or more fixed driving stages, thereby turning on said MEMS G-switch.

7. The MEMS G-switch according to claim 6, wherein said voltage control circuit applies a second working voltage to said one or more moveable driving stages when said one or more moveable driving stages collapse onto said one or more fixed driving stages.

8. The MEMS G-switch according to claim 1, wherein said G-switch is turned on by:

providing said G-switch in an open position with a first working voltage applied to said moveable driving stages by said voltage control circuit;

moving of said one or more moveable driving stages'"'"' sensing direction towards gravity at a first critical angle, whereby said moveable driving stages collapse and stick to said fixed driving stages through said bumps thereby turning on said G-switch; and

reducing said first working voltage to a second working voltage to keep said moveable driving stages sticking to said fixed driving stages.

9. The MEMS G-switch according to claim 8, wherein the angle between said one or more moveable driving stages'"'"' sensing direction and gravity of said proof mass decreases to a first critical angle and said MEMS G-switch turns on.

10. The MEMS G-switch according to claim 1 wherein said G-switch is turned off by:

applying a second working voltage to said moveable driving stages by said voltage control circuit; and

moving of said one or more moveable driving stages'"'"' sensing direction away from gravity to a second critical angle, wherein said moveable driving stages deviate from said fixed driving stages thereby turning off said G-switch.

11. The MEMS G-switch according to claim 10, wherein the angle between said one or more moveable driving stages'"'"' sensing direction and gravity of said proof mass increases to a second critical angle and said MEMS G-switch turns off.

12. A MEMS G-switch comprising:

a substrate;

a proof-mass;

a fixed driving stage attached to said substrate;

a plurality of mechanical springs;

a moveable driving stage attached to said proof mass and suspended above said substrate by said plurality of mechanical springs;

a voltage control circuit applying working voltage to said moveable and fixed driving stages; and

a bump attached between said fixed and said moveable driving stages;

wherein, when said MEMS G-switch is turned off, a first working voltage is applied to said moveable driving stage, thereby moving said moveable driving stage'"'"'s sensing direction towards gravity at a first critical angle, thereby causing said movable driving stage to touch said fixed driving stage through said bump, and thereby turning on said MEMS G-switch; and

wherein, when said MEMS G-switch is turned on, a second working voltage is applied to said moveable driving stage, thereby moving said moveable driving stage'"'"'s sensing direction away from gravity at a second critical angle, thereby causing said movable driving stage to separate from said fixed driving stage, and thereby turning off said MEMS G-switch.

13. The MEMS G-switch according to claim 12, wherein application of said first and second working voltages is performed by said voltage control circuit.

14. The MEMS G-switch according to claim 12, wherein said first working voltage is higher than said second working voltage.

15. The MEMS G-switch according to claim 12, wherein said first critical angle to turn on said MEMS G-switch is smaller than said second critical angle to turn off said MEMS G-switch.

16. A MEMS G-switch comprising:

a substrate;

a proof-mass;

one or more moveable driving stages attached to said proof mass;

a plurality of mechanical springs each having one end attached to said substrate and another end attached to said moveable driving stages;

one or more fixed driving stages attached to said substrate;

bumps attached on said fixed driving stages or said moveable driving stages; and

a voltage control circuit applying voltage between said moveable driving stages and said fixed driving stages;

wherein, when a sensing direction of said one or more moveable driving stages is moved away from gravity at a second critical angle, said one or more moveable driving stages are separated from said one or more fixed driving stages and a first working voltage is applied to them by said voltage control circuit, and said MEMS G-switch is turned off; and

wherein, when a sensing direction of said one or more moveable driving stages is moved towards gravity at a first critical angle, said one or more moveable driving stages touch said fixed driving stages through said bumps and a second working voltage is applied to them by said voltage control circuit, and said MEMS G-switch is turned on.

17. A method for manufacturing a MEMS G-switch comprising:

providing a substrate;

forming a proof-mass in or above said substrate;

providing one or more fixed driving stages attached to said substrate;

attaching one or more moveable driving stages to said proof mass;

providing a plurality of mechanical springs to suspend said one or more moveable driving stages above said substrate;

providing one or more bumps attached between said fixed and said moveable driving stages; and

providing a voltage control circuit to control two working voltages applied to said one or more driving stages alternatively wherein said G-switch is turned off when it is in an orientation perpendicular to the direction of gravity and said one or more moveable driving stages deviate from said one or more fixed driving stages and wherein said G-switch is turned on when it is in an orientation parallel to the direction of gravity and the gravity force of said proof mass pulls said one or more moveable driving stages to collapse onto said one or more fixed driving stages.

18. The method according to claim 17 wherein said step of providing a plurality of mechanical springs to suspend said one or more moveable driving stages above said substrate comprises:

attaching said one or more mechanical springs between said proof-mass and said substrate.

19. The method according to claim 17 wherein said step of providing a plurality of mechanical springs to suspend said one or more moveable driving stages above said substrate comprises:

connecting first beams between said proof-mass and said one or more moveable driving stages; and

connecting second beams between each of said one or more moveable driving stages and an anchor attached to said substrate.

20. The method according to claim 19 wherein said one or more moveable driving stages comprise driving electrodes which also act as signal lines for switching.

21. The method according to claim 19 wherein said substrate acts as said one or more fixed driving stages and wherein said bumps are on a bottom surface of said one or more moveable driving stages or on a top surface of said substrate.

22. The method according to claim 19 wherein said step of providing a plurality of mechanical springs to suspend said one or more moveable driving stages above said substrate comprises:

supporting said proof-mass and said one or more moveable driving stages on one or more U-shaped beams connected to said substrate by anchors.

23. A MEMS G-switch comprising:

a substrate;

a proof-mass formed through said substrate wherein a top surface of said substrate forms a fixed driving stage;

one or more movable driving stages located over said top surface of said substrate and connected by first beams to said proof-mass wherein second beams are connected between each of said one or more moveable driving stages and an anchor attached to said top surface of said substrate;

a voltage control circuit applying working voltage to said moveable driving stages; and

a bump attached between said fixed and said moveable driving stages;

wherein, when said MEMS G-switch is turned off, a first working voltage is applied to said one or more moveable driving stages, thereby moving said moveable driving stage'"'"'s sensing direction towards gravity at a first critical angle, thereby causing said one or more movable driving stage to touch said fixed driving stage through said bump, and thereby turning on said MEMS G-switch; and

wherein, when said MEMS G-switch is turned on, a second working voltage is applied to said one or more moveable driving stages, thereby moving said one or more moveable driving stages'"'"' sensing direction away from gravity at a second critical angle, thereby causing said one or more movable driving stages to separate from said fixed driving stage, and thereby turning off said MEMS G-switch.

24. The MEMS G-switch according to claim 23 wherein said proof mass is formed fully or partially through said substrate.

25. The MEMS G-switch according to claim 23 wherein said four movable driving stages are located symmetrically around said proof mass.

26. The MEMS G-switch according to claim 23 wherein said first and second beams also act as signal lines for switching and are connected to contact sections on said anchors.

27. The MEMS G-switch according to claim 23 wherein said one or more moveable driving stages comprise driving electrodes and wherein said substrate acts as a common fixed electrode under said driving electrodes.

28. The MEMS G-switch according to claim 23 wherein said bumps are on a bottom surface of said one or more moveable driving stages or on a top surface of said substrate.

29. The MEMS G-switch according to claim 23 wherein said second beams are U-type beams formed by cambered beams connected to said anchors.