Mems device and a method of using the same

Abstract

A method of using a MEMS gyroscope is disclosed herein, wherein the MEMS gyroscope comprised a magnetic sensing mechanism. A magnetic field is generated by a magnetic source, and is detected by a magnetic sensor. The magnetic field varies at the location of the magnetic sensor; and the variation of the magnetic field is associated with the movement of the proof-mass of the MEMS gyroscope. By detecting the variation of the magnetic field, the movement and thus the target angular velocity can be measured.

We claim: 
     
         1 . A method of measuring an angular velocity by using a MEMS gyroscope, the method comprising:
 generating a magnetic field that is associated with a movement of a proof-mass of the MEMS gyroscope, wherein the magnetic field varies at a location of a magnetic sensor;   detecting the variation of the magnetic field by the magnetic sensor; and   extracting the angular velocity from the variation of the magnetic field.   
     
     
         2 . The method of  claim 1 , wherein the step of generating the magnetic field comprises:
 driving a current through a conductive wire so as to generating the magnetic field.   
     
     
         3 . The method of  claim 2 , wherein the magnetic sensor comprises a spin-valve structure. 
     
     
         4 . The method of  claim 2 , wherein the magnetic sensor comprises a tunneling-magneto-resistor structure. 
     
     
         5 . The method of  claim 2 , further comprising:
 before generating the magnetic field, detecting a magnetic signal from a background in which the magnetic field to be generated co-exists; and   wherein the step of extracting the angular velocity further comprises:
 extracting the angular velocity from said detected magnetic signal from the background and the variation of the magnetic field. 
   
     
     
         6 . A method of detecting a target angular velocity, comprising:
 providing a MEMS gyroscope that comprises a movable proof-mass, a magnetic source, and a magnetic sensor, wherein the proof-mass is capable of moving in response to the target angular velocity under the Coriolis effect, and wherein the magnetic source is capable of generating a magnetic field that varies with the movement of the proof-mass, and wherein the magnetic sensor is capable of detecting the magnetic field from the magnetic source;   generating the magnetic field by the magnetic source;   detecting a variation of the magnetic field by the magnetic sensor; and   extracting the angular velocity from the variation of the magnetic field.   
     
     
         7 . The method of  claim 6 , wherein the step of generating the magnetic field comprises:
 driving a current through a conductive wire so as to generating the magnetic field.   
     
     
         8 . The method of  claim 7 , wherein the magnetic sensor comprises a spin-valve structure. 
     
     
         9 . The method of  claim 7 , wherein the magnetic sensor comprises a tunneling-magneto-resistor structure. 
     
     
         10 . The method of  claim 7 , further comprising:
 before generating the magnetic field, detecting a magnetic signal from a background in which the magnetic field to be generated co-exists; and   wherein the step of extracting the angular velocity further comprises:
 extracting the angular velocity from said detected magnetic signal from the background and the variation of the magnetic field. 
   
     
     
         11 . A method of measuring an angular velocity by using a MEMS gyroscope, the method comprising:
 detecting a background magnetic signal by a reference magnetic sensor of the MEMS gyroscope;   locking the state of the reference sensor after the detection of the background magnetic signal;   generating a magnetic field by a magnetic source whose movement is associated with a proof-mass of the MEMS gyroscope;   detecting the magnetic field from the magnetic source by a signal sensor; and   calculating the angular velocity from the detected magnetic field.   
     
     
         12 . The method of  claim 11 , further comprising:
 locking the signal sensor after the step of detecting the magnetic field by the signal sensor and before the step of calculating the angular velocity.   
     
     
         13 . The method of  claim 12 , wherein the step of generating the magnetic field comprises:
 driving a current through a conductive wire so as to generating the magnetic field.   
     
     
         14 . The method of  claim 13 , wherein the magnetic sensor comprises a spin-valve structure. 
     
     
         15 . The method of  claim 13 , wherein the magnetic sensor comprises a tunneling-magneto-resistor structure.