Lateral Piezoelectric Driven Highly Tunable Micro-electromechanical System (MEMS) Inductor

• US 20080061916A1
• Filed: 11/08/2007
• Published: 03/13/2008
• Est. Priority Date: 03/20/2006
• Status: Active Grant

• Current Assignee: United States Of America As Represented By The Secretary Of The Army (Government of the United States of America)
• Original Assignee: The United States of America As Represented By The Secretary of Agriculture
• Inventors: Pulskamp, Jeffrey
• Granted Patent: US 7,486,002 B2
• Time in Patent Office: Days
• US Class Current: 336/130
• CPC Class Codes: H01F 21/06 by movement of core or part of core relative to the windings as a whole

Abstract

A MEMS device comprising a substrate; an anchored end connected to the substrate; and an actuator comprising a first electrode; a piezoelectric layer over the first electrode; and multiple sets of second electrodes over the piezoelectric layer, wherein each of the sets of second electrodes being defined by a transverse gap there between, and wherein one of the sets of second electrodes are actuated asymmetrically with respect to a first plane resulting in a piezoelectrically induced bending moment arm in a lateral direction that lies in a second plane. The device further comprises an end effector opposite to the anchored end and connected to the actuator; a ferromagnetic core support structure connected to the end effector; a movable ferromagnetic inductor core on top of the ferromagnetic core support structure; and a MEMS inductor coiled around the ferromagnetic core support structure and the movable ferromagnetic inductor core.

Claims

1. A microelectromechanical system (MEMS) device comprising:

a substrate;

an anchored end connected to said substrate;

an actuator comprising;

a first electrode;

a piezoelectric layer over said first electrode; and

multiple sets of second electrodes over said piezoelectric layer, wherein each of said sets of second electrodes being defined by a transverse gap there between, and wherein one of said sets of second electrodes are actuated asymmetrically with respect to a first plane resulting in a piezoelectrically induced bending moment arm in a lateral direction that lies in a second plane;

an end effector opposite to said anchored end and connected to said actuator;

a ferromagnetic core support structure connected to said end effector;

a movable ferromagnetic inductor core on top of said ferromagnetic core support structure; and

a MEMS inductor coiled around said ferromagnetic core support structure and said movable ferromagnetic inductor core.

2. The device of claim 1, wherein said ferromagnetic core support structure comprises:

a base portion connected to said end effector; and

a plurality of finger-like projections extending from said base portion.

3. The device of claim 2, wherein said movable ferromagnetic inductor core is on top of said plurality of finger-like projections of said ferromagnetic core support structure.

4. The device of claim 1, further comprising:

multiple actuation beams; and

multiple connection beams adapted to connect said multiple actuation beams to one another.

5. The device of claim 4, wherein each of said multiple actuation beams comprise two sets of said second electrodes.

6. The device of claim 1, wherein said set of second electrodes comprise an extensional electrode and a contraction electrode.

7. The device of claim 1, further comprising a spring attached to said end effector, wherein said spring comprises a residual stress deformation mitigation spring adapted to prevent out-of-plane stress deformation of said actuator.

8. The device of claim 1, further comprising a spring attached to said end effector, wherein said spring comprises a residual stress deformation mitigation spring adapted to restrict translational motion of said end effector to be within said second planes and wherein said first plane is transverse to said second plane.

9. A microelectromechanical system (MEMS) device comprising:

at least one actuation beam comprising;

a continuous lower electrode;

a piezoelectric layer over said lower electrode; and

at least one pair of upper electrodes over said piezoelectric layer;

an anchored end connected to said at least one actuation beam;

an end effector opposite to said anchored end and connected to said at least one actuation beam;

a spring connected to said end effector;

a ferromagnetic core support structure connected to said end effector;

a movable ferromagnetic inductor core on top of said ferromagnetic core support structure; and

a MEMS inductor coiled around said ferromagnetic core support structure and said movable ferromagnetic inductor core.

10. The device of claim 9, wherein said ferromagnetic core support structure comprises:

a base portion connected to said end effector; and

a plurality of finger-like projections extending from said base portion.

11. The device of claim 10, wherein said movable ferromagnetic inductor core is on top of said plurality of finger-like projections of said ferromagnetic core support structure.

12. The device of claim 9, further comprising connection beams adapted to connect multiple actuation beams to one another.

13. The device of claim 9, wherein said at least one actuation beam comprises multiple pairs of said upper electrodes.

14. The device of claim 9, wherein said pair of upper electrodes comprises a first electrode and a second electrode, and wherein said pair of upper electrodes comprising a gap between said first electrode and said second electrode.

15. The device of claim 9, wherein said pair of upper electrodes comprise an extensional electrode and a contraction electrode.

16. The device of claim 9, wherein said spring member comprises a residual stress deformation mitigation spring adapted to prevent out-of-plane stress deformation of said actuation beam.

17. The device of claim 13, wherein one of said multiple pairs of upper electrodes are actuated asymmetrically with respect to a first plane resulting in a piezoelectrically induced bending moment arm in a lateral direction that lies in a second plane.

18. The device of claim 17, wherein said spring member comprises a residual stress deformation mitigation spring adapted to restrict translational motion of said end effector to be within said second plane, and wherein said first plane is transverse to said second plane.

19. The device of claim 9, further comprising a silicon substrate attached to said anchored end

20. A microelectromechanical system (MEMS) device having a first end and a second end, said device comprising:

a sensor comprising;

a piezoelectric layer; and

multiple electrodes sandwiching said piezoelectric layer, said multiple electrodes comprising a continuous first electrode attached to a first side of said piezoelectric layer and at least one pair of second electrodes attached to a second side of said piezoelectric layer, wherein said pair of second electrodes comprises a primary electrode and a secondary electrode defined by a transverse gap there between;

a substrate anchored to said first end;

an end effector attached to said second end;

a spring member attached to said end effector;

an anchored end connected to said sensor;

an end effector opposite to said anchored end and connected to said sensor;

a ferromagnetic core support structure connected to said end effector;

a movable ferromagnetic inductor core on top of said ferromagnetic core support structure; and

a MEMS inductor coiled around said ferromagnetic core support structure and said movable ferromagnetic inductor core,

wherein said multiple electrodes are adapted to receive voltage, said voltage causing said end effector to laterally deflect in a geometric plane of said substrate