# US 2014/0190257 A1 · Mems device and a method of using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0190257 A1 - Document ID: US20140190257A1 - Status: Published application - Kind: A1 - Application number: 13/936,143 - Filed: 2013-07-06 - Published: 2014-07-10 - Earliest claimed: 2012-07-27 - Inventors: Biao Zhang; Tao Ju - Web page: https://patentgrep.com/patent/US20140190257A1 ## CPC - G01P 15/105: by magnetically sensitive devices - B81B 5/00: Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements - B81C 1/00357: {involving bonding one or several substrates on a non-temporary support, e.g. another substrate} - B81C 3/001: {Bonding of two components} - G01C 19/56: Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces - G01C 19/5712: the devices involving a micromechanical structure - G01C 19/5776: Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719 - G01P 15/125: by capacitive pick-up - G01R 33/091: {Constructional adaptation of the sensor to specific applications} - G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)} - G01R 33/098: {comprising tunnel junctions, e.g. tunnel magnetoresistance sensors} - B81C 2201/0197: Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192 - B81C 2203/038: Bonding techniques not provided for in B81C2203/031 - B81C2203/037 - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) ## 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. ## Claims ### Claim 1 A method of measuring an angular velocity by using a MEMS gyroscope, the method comprising: driving the proof-mass to move in a driving mode using a group of capacitors; measuring a background magnetic signal using a reference magnetic sensor; storing the measurement from the reference magnetic sensor; generating a target magnetic field that is associated with a movement of a proof-mass of the MEMS gyroscope; activating a signal magnetic sensor for measuring the background magnetic signal and the generated target magnetic signal; comparing the measurements from the reference and signal magnetic sensors so as to obtain the target magnetic field; and extracting the angular velocity from the target magnetic field. ### Claim 2 (depends on 1) The method of claim 1, wherein the step of measuring the background magnetic signal comprises: raising the temperature of the reference magnetic sensor above a blocking temperature of the reference sensor such that the reference sensor is capable of detecting the background magnetic field signal. ### Claim 3 (depends on 2) The method of claim 2, wherein the reference sensor comprises a free layer for detecting the background magnetic field signal, wherein the free layer is magnetically pinned by an antiferromagnetic layer when the temperature is blow the blocking temperature. ### Claim 4 (depends on 2) The method of claim 2, wherein the step of generating the magnetic field comprises: driving a current through a conductive wire so as to generating the magnetic field. ### Claim 5 (depends on 4) The method of claim 4, wherein the magnetic sensor comprises a spin-valve structure. ### Claim 6 (depends on 4) The method of claim 4, wherein the magnetic sensor comprises a tunneling-magneto-resistor structure. ### Claim 7 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; detecting a background magnetic signal using a reference sensor; storing the detected background magnetic signal by the reference sensor; causing the proof-mass to vibrate using a group of capacitors; 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. ### Claim 8 (depends on 7) The method of claim 7, wherein the step of measuring the background magnetic signal comprises: raising the temperature of the reference magnetic sensor above a blocking temperature of the reference sensor such that the reference sensor is capable of detecting the background magnetic field signal. ### Claim 9 (depends on 8) The method of claim 8, wherein the reference sensor comprises a free layer for detecting the background magnetic field signal, wherein the free layer is magnetically pinned by an antiferromagnetic layer when the temperature is blow the blocking temperature. ### Claim 10 (depends on 8) The method of claim 8, wherein the step of generating the magnetic field comprises: driving a current through a conductive wire so as to generating the magnetic field. ### Claim 11 (depends on 8) The method of claim 8, wherein the magnetic sensor comprises a spin-valve structure. ### Claim 12 (depends on 8) The method of claim 8, wherein the magnetic sensor comprises a tunneling-magneto-resistor structure.