Microelectromechanical system sensor and method for using

• US 7,253,615 B2
• Filed: 05/05/2004
• Issued: 08/07/2007
• Est. Priority Date: 05/05/2004
• Status: Expired due to Fees

• Current Assignee: Amphenol Thermometrics, Inc. (Amphenol Corporation)
• Original Assignee: General Electric Company
• Inventors: Berkcan, Ertugrul, Tian, Wei-Cheng
• Primary Examiner(s): Lefkowitz; Edward
• Assistant Examiner(s): WHITTINGTON, KENNETH
• Application Number:
  US10/839,095
• Publication Number:
  US 20050248340A1
• Time in Patent Office: 1,189 Days
• Field of Search: 324/244, 324/252, 324/259, 324/260, 324/207.14, 324/658, 324/660, 324/661, 324/686, 324/690, 735/143.2, 735/143.3, 735/143.4
• US Class Current: 324/244
• CPC Class Codes: G01R 15/148 involving the measuring of a magnetic field or electric field G01R15/18, G01R15/20, G01R15/24, G01R15/26 take precedence
• CPC Class Codes: G01R 33/0283 in which a current or voltage is generated due to relative movement of conductor and magnetic field
• CPC Class Codes: G01R 33/0286 comprising microelectromechanical systems [MEMS] MEMS devices in general B81B

Abstract

According to some embodiments, an apparatus includes a movable portion through which a sensing current is to be conducted. The movable portion might comprise, for example, a beam or plate suspended above a well in a Microelectromechanical System (MEMS) substrate. The apparatus may also include a sensing portion coupled to the movable portion, and the movable portion and/or sensing portion may move in a direction normal to the substrate in response to a magnetic field.

Claims

1. An apparatus, comprising:

a substrate having a surface;

a fixed comb mounted to the substrate and disposed generally parallel to the substrate surface;

a movable portion through which a sensing current is to be conducted; and

a comb-like sensing portion coupled to the movable portion and interleaved with the fixed comb, wherein the movable portion moves in a direction normal to the substrate surface in response to a magnetic field to produce a measurement resulting from movement of fingers of the sensing portion with respect to the fixed comb in the normal direction.

2. The apparatus of claim 1, wherein the substrate is associated with a microelectromechanical system wafer and the movable portion is positioned substantially parallel to the substrate surface.

3. The apparatus of claim 1, wherein the strength of the magnetic field is to be measured based on a piezoresistance change associated with the sensing portion.

4. The apparatus of claim 1, wherein the apparatus is a sensor in an array of sensors.

5. The apparatus of claim 1, wherein the apparatus is at least one of:

(i) a magnetic field sensor, and (ii) an electrical current sensor.

6. The apparatus of claim 1, wherein the suspended plate has a first conducting path and a second conducting path.

7. The apparatus of claim 6, wherein the sensing current is to move through the two paths in a single direction.

8. The apparatus of claim 6, wherein the sensing current is to move through the two paths in opposite directions.

9. The apparatus of claim 1, wherein the strength of the magnetic field is to be measured based on a change in capacitance between the sensing comb and the fixed comb.

10. The apparatus of claim 1, wherein the strength of the magnetic field is to be measured based on a quality factor change between the sensing comb and the fixed comb.

11. The apparatus of claim 10, wherein the change in quality factor is determined in connection with at least one of:

(i) a resonant frequency, (ii) mutual inductance coupling, and (iii) a mutually inductive voltage.

12. An apparatus, comprising:

a fixed comb;

a movable portion through which a sensing current is to be conducted; and

a comb-like sensing portion coupled to the movable portion and interleaved with the fixed comb, wherein the movable portion moves in response to a magnetic field in two orthogonal directions including a direction normal to a substrate to produce a measurement resulting from movement of fingers of the sensing portion with respect to the fixed comb in the normal direction.

13. The apparatus of claim 12, wherein the substrate is associated with a microelectromechanical system wafer.

14. The apparatus of claim 12, wherein the strength of the magnetic field is to be measured based on at least one of:

(i) a change in capacitance, (ii) a quality factor change, and (iii) a piezoresistance change.

15. The apparatus of claim 14, wherein the apparatus is at least one of:

(i) a magnetic field sensor, and (ii) an electrical current sensor.

16. A method of sensing an electromagnetic value, comprising:

providing a sensing current through a movable portion of a sensor, the movable portion comprising a comb-like portion interleaved with a fixed comb that is mounted to a substrate and generally parallel to a surface of the substrate; and

measuring an electrical characteristic of the sensing portion coupled to the movable portion when the movable portion moves in a direction normal to the substrate surface in response to a magnetic field to produce a measurement resulting from movement of fingers of the sensing portion with respect to the fixed comb in the normal direction.

17. The method of claim 16, wherein electrical characteristic is associated with at least one of:

(i) a change in capacitance, (ii) a quality factor change, and (iii) a piezoresistance change.

18. The method of claim 17, further comprising:

determining, based on the measured electrical characteristic, at least one of;

(i) a magnetic field value, and (ii) an electrical current value.

19. A system, comprising:

a substrate having a surface;

a fixed comb mounted to the substrate and disposed generally parallel to the substrate surface;

a microelectromechanical system sensor, including;

a movable portion through which a sensing current is to be conducted, and

a comb-like sensing portion coupled to the movable portion and interleaved with the fixed comb, wherein the movable portion moves in a direction normal to the substrate surface in response to a magnetic field to produce a measurement resulting from movement of fingers of the sensing portion with respect to the fixed comb in the normal direction; and

a sensor dependent device.

20. The system of claim 19, wherein the sensor dependent device is associated with at least one of:

(i) a security device, (ii) a medical device, (iii) an electrical controller, (iv) a power distribution device, (v) a power meter, (vi) a circuit breaker, (vii) a consumer device, and (viii) a motor control device.