US20160153780A1 - Mems gyroscope - Google Patents
Mems gyroscope Download PDFInfo
- Publication number
- US20160153780A1 US20160153780A1 US14/518,607 US201414518607A US2016153780A1 US 20160153780 A1 US20160153780 A1 US 20160153780A1 US 201414518607 A US201414518607 A US 201414518607A US 2016153780 A1 US2016153780 A1 US 2016153780A1
- Authority
- US
- United States
- Prior art keywords
- magnetic
- proof
- mass
- mems gyroscope
- sensing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/105—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by magnetically sensitive devices
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
- B81B5/00—Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
- B81C1/00349—Creating layers of material on a substrate
- B81C1/00357—Creating layers of material on a substrate involving bonding one or several substrates on a non-temporary support, e.g. another substrate
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C3/00—Assembling of devices or systems from individually processed components
- B81C3/001—Bonding of two components
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/5705—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using masses driven in reciprocating rotary motion about an axis
- G01C19/5712—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using masses driven in reciprocating rotary motion about an axis the devices involving a micromechanical structure
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
- G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
- G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
- G01C19/5776—Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
- G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
- G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
- G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/091—Constructional adaptation of the sensor to specific applications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/093—Magnetoresistive devices using multilayer structures, e.g. giant magnetoresistance sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/09—Magnetoresistive devices
- G01R33/098—Magnetoresistive devices comprising tunnel junctions, e.g. tunnel magnetoresistance sensors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2201/00—Manufacture or treatment of microstructural devices or systems
- B81C2201/01—Manufacture or treatment of microstructural devices or systems in or on a substrate
- B81C2201/0174—Manufacture or treatment of microstructural devices or systems in or on a substrate for making multi-layered devices, film deposition or growing
- B81C2201/0197—Processes for making multi-layered devices not provided for in groups B81C2201/0176 - B81C2201/0192
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B81—MICROSTRUCTURAL TECHNOLOGY
- B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
- B81C2203/00—Forming microstructural systems
- B81C2203/03—Bonding two components
- B81C2203/038—Bonding techniques not provided for in B81C2203/031 - B81C2203/037
Definitions
- the technical field of the examples to be disclosed in the following sections is related generally to the art of operation of microstructures, and, more particularly, to operation of MEMS devices comprising MEMS magnetic sensing structures.
- Microstructures such as microelectromechanical (hereafter MEMS) devices (e.g. accelerometers, DC relay and RF switches, optical cross connects and optical switches, microlenses, reflectors and beam splitters, filters, oscillators and antenna system components, variable capacitors and inductors, switched banks of filters, resonant comb-drives and resonant beams, and micromirror arrays for direct view and projection displays) have many applications in basic signal transduction. For example, a MEMS gyroscope measures angular rate.
- MEMS microelectromechanical
- a gyroscope (hereafter “gyro” or “gyroscope”) is based on the Coriolis effect as diagrammatically illustrated in FIG. 1 .
- Proof-mass 100 is moving with velocity V d .
- the Coriolis effect causes movement of the poof-mass ( 100 ) with velocity V s .
- V d With fixed V d , the external angular velocity can be measured from V d .
- a typical example based on the theory shown in FIG. 1 is capacitive MEMS gyroscope, as diagrammatically illustrated in FIG. 2 .
- the MEMS gyro is a typical capacitive MEMS gyro, which has been widely studied. Regardless of various structural variations, the capacitive MEMS gyro in FIG. 2 includes the very basic theory based on which all other variations are built.
- capacitive MEMS gyro 102 is comprised of proof-mass 100 , driving mode 104 , and sensing mode 102 .
- the driving mode ( 104 ) causes the proof-mass ( 100 ) to move in a predefined direction, and such movement is often in a form of resonance vibration. Under external angular rotation, the proof-mass ( 100 ) also moves along the V s direction with velocity V s .
- Such movement of V s is detected by the capacitor structure of the sensing mode ( 102 ).
- Both of the driving and sensing modes use capacitive structures, whereas the capacitive structure of the driving mode changes the overlaps of the capacitors, and the capacitive structure of the sensing mode changes the gaps of the capacitors.
- a MEMS gyroscope comprising: a first substrate, comprising: a pair of movable portions that are capable of moving in opposite directions in response to an angular velocity along a sensing direction; a pair of driving mechanisms associated with said movable portions for moving the movable portions in opposite directions along a driving direction that is substantially perpendicular to the sensing direction; a plurality of magnetic sources attached to at least one of the movable portions for generating magnetic field; and a reference sensor associated with said plurality of magnetic sensors for providing a reference signal; and a second substrate having a plurality of magnetic sensors that are a spintronic device for measuring the magnetic field from the conducting wire, wherein the magnetic sensors form a part of a Wheatstone bridge.
- FIG. 1 diagrammatically illustrates the Coriolis effect in a MEMS structure
- FIG. 2 is a top view of a typical existing capacitive MEMS gyroscope having a driving mode and a sensing mode, wherein both of the driving and sensing mode utilize capacitance structures;
- FIG. 3 illustrates an exemplary MEMS gyroscope having a magnetic sensing mechanism
- FIG. 4 illustrates a top view of a portion of an exemplary implementation of the MEMS gyroscope illustrated in FIG. 3 , wherein the MEMS gyroscope illustrated in FIG. 4 having a capacitive driving mode and a magnetic sensing mechanism;
- FIG. 5 illustrates a perspective view of a portion of another exemplary implementation of the MEMS gyroscope illustrated in FIG. 3 , wherein the MEMS gyroscope illustrated in FIG. 5 having a magnetic driving mechanism for the driving mode and a magnetic sensing mechanism for the sensing mode
- FIG. 6 illustrates an exemplary magnetic driving mechanism of the MEMS gyroscope in FIG. 5 ;
- FIG. 7 illustrates an exemplary magnetic source of the MEMS gyroscope illustrated in FIG. 3 ;
- FIG. 8 illustrates an exemplary magnetic sensing mechanism that can be used in the MEMS gyroscope illustrated in FIG. 3 ;
- FIG. 9 shows an exemplary thin-film stack that can be configured into a CIP or CPP structure for use in the magnetic sensing mechanism illustrated in FIG. 8 ;
- FIG. 10 illustrates an exemplary MEMS gyroscope that comprises multiple magnetic sensing structures
- FIG. 11 illustrates an exemplary MEMS gyroscope that comprises multiple proof-masses
- FIG. 12 illustrates an exemplary MEMS gyroscope that comprises multiple proof-masses having magnetic driving mechanisms
- FIG. 13 a and FIG. 13 b illustrate an exemplary driving scheme for use in the MEMS gyroscope illustrated in FIG. 12 ;
- FIG. 14 illustrates an exemplary magnetic source and magnetic sensing mechanism of the MEMS gyroscope illustrated in FIG. 13 ;
- FIG. 15 illustrates another exemplary MEMS gyroscope that comprises multiple proof-masses having capacitive driving mechanisms
- FIG. 16 a and FIG. 16 b illustrate yet another exemplary MEMS gyroscope comprising multiple proof-masses and multiple magnetic sources in at least one of the proof-masses;
- FIG. 17 illustrates yet another exemplary MEMS gyroscope comprising multiple proof-masses, multiple magnetic sources in at least one of the proof-masses, and a reference magnetic sensor for the multiple magnetic sensors.
- MEMS gyroscope for sensing an angular velocity, wherein the MEMS gyroscope utilizes a magnetic sensing mechanism. It will be appreciated by those skilled in the art that the following discussion is for demonstration purposes, and should not be interpreted as a limitation. Many other variations within the scope of the following disclosure are also applicable. For example, the MEMS gyroscope and the method disclosed in the following are applicable for use in accelerometers.
- MEMS gyroscope 106 comprises magnetic sensing mechanism 114 for sensing the target angular velocity through the measurement of proof-mass 112 .
- MEMS gyroscope 106 comprises mass-substrate 108 and sensor substrate 110 .
- Mass-substrate 108 comprises proof-mass 112 that is capable of responding to an angular velocity.
- the two substrates ( 108 and 110 ) are spaced apart, for example, by a pillar (not shown herein for simplicity) such that at least the proof-mass ( 112 ) is movable in response to an angular velocity under the Coriolis effect.
- the movement of the proof-mass ( 112 ) and thus the target angular velocity can be measured by magnetic sensing mechanism 114 .
- the magnetic sensing mechanism ( 114 ) in this example comprises a magnetic source 116 and magnetic sensor 118 .
- the magnetic source ( 116 ) generates a magnetic field
- the magnetic sensor ( 118 ) detects the magnetic field and/or the magnetic field variations that is generated by the magnetic source ( 116 ).
- the magnetic source is placed on/in the proof-mass ( 112 ) and moves with the proof-mass ( 112 ).
- the magnetic sensor ( 118 ) is placed on/in the sensor substrate ( 120 ) and non-movable relative to the moving proof-mass ( 112 ) and the magnetic source ( 116 ). With this configuration, the movement of the proof-mass ( 112 ) can be measured from the measurement of the magnetic field from the magnetic source ( 116 ).
- the magnetic source ( 116 ) can be placed on/in the sensor substrate ( 120 ); and the magnetic sensor ( 118 ) can be placed on/in the proof-mass ( 112 ).
- MEMS gyroscope illustrated in FIG. 3 can also be used as an accelerometer.
- the MEMS gyroscope as discussed above with reference to FIG. 3 can be implemented in many ways, one of which is illustrated in FIG. 4 .
- the proof-mass ( 120 ) is driven by capacitive, such as capacitive comb.
- the sensing mode is performed using the magnetic sensing mechanism illustrated in FIG. 3 . For this reason, capacitive combs can be absent from the proof-mass ( 120 ).
- the proof-mass can be driven by magnetic force, an example of which is illustrated in FIG. 5 .
- the mass substrate ( 108 ) comprises a movable proof-mass ( 126 ) that is supported by flexible structures such as flexures 128 , 129 , and 130 .
- the layout of the flexures enables the proof-mass to move in a plane substantially parallel to the major planes of mass substrate 108 .
- the flexures enables the proof-mass to move along the length and the width directions, wherein the length direction can be the driving mode direction and the width direction can be the sensing mode direction of the MEMS gyro device.
- the proof-mass ( 126 ) is connected to frame 132 through flexures ( 128 , 129 , and 130 ).
- the frame ( 132 ) is anchored by non-movable structures such as pillar 134 .
- the mass-substrate ( 108 ) and sensing substrate 110 are spaced apart by the pillar ( 134 ).
- the proof-mass ( 112 ) in this example is driving by a magnetic driving mechanism ( 136 ).
- the proof-mass ( 126 ) can move (e.g. vibrate) in the driving mode under magnetic force applied by magnetic driving mechanism 136 , which is better illustrated in FIG. 6 .
- the magnetic driving mechanism 136 comprise a magnet core 138 surrounded by coil 140 .
- an alternating magnetic field can be generated from the coil 140 .
- the alternating magnetic field applies magnetic force to the magnet core 140 so as to move the magnet core.
- the magnet core thus moves the proof-mass.
- the magnetic source ( 114 ) of the MEMS gyroscope ( 106 ) illustrated in FIG. 3 can be implemented in many ways, one of which is illustrated in FIG. 7 .
- conductive wire 142 is displaced on/in proof-mass 112 .
- conductive wire 142 can be placed on the lower surface of the proof-mass ( 112 ), wherein the lower surface is facing the magnetic sensors ( 118 in FIG. 3 ) on the sensor substrate ( 110 , in FIG. 3 ).
- the conductive wire ( 142 ) can be placed on the top surface of the proof-mass ( 112 ), i.e.
- the conductive wire ( 142 ) can be placed inside the proof-mass, e.g. laminated or embedded inside the proof-mass ( 112 ), which will not be detailed herein as those examples are obvious to those skilled in the art of the related technical field.
- the conductive wire ( 142 ) can be implemented in many suitable ways, one of which is illustrated in FIG. 7 .
- the conductive wire ( 142 ) comprises a center conductive segment 146 and tapered contacts 144 and 148 that extend the central conductive segment to terminals, through the terminals of which current can be driven through the central segment.
- the conductive wire ( 142 ) may have other configurations.
- the contact tapered contacts ( 144 and 148 ) and the central segment ( 146 ) maybe U-shaped such that the tapered contacts may be substantially parallel but are substantially perpendicular to the central segment, which is not shown for its obviousness.
- the magnetic sensor ( 118 ) illustrated in FIG. 3 can be implemented to comprise a reference sensor ( 150 ) and a signal sensor ( 152 ) as illustrated in FIG. 8 .
- magnetic senor 118 on/in sensor substrate 120 comprises reference sensor 150 and signal sensor 152 .
- the reference sensor ( 150 ) can be designated for dynamically measuring the magnetic signal background in which the target magnetic signal (e.g. the magnetic field from the conductive wire 146 as illustrated in FIG. 7 ) co-exists.
- the signal sensor ( 152 ) can be designated for dynamically measuring the target magnetic signal (e.g. the magnetic field from the conductive wire 146 as illustrated in FIG. 7 ).
- the signal sensor ( 152 ) can be designated for dynamically measuring the magnetic signal background in which the target magnetic signal (e.g. the magnetic field from the conductive wire 146 as illustrated in FIG. 7 ) co-exists, while the signal sensor ( 150 ) can be designated for dynamically measuring the target magnetic signal (e.g. the magnetic field from the conductive wire 146 as illustrated in FIG. 7 ).
- the reference sensor ( 150 ) and the signal sensor ( 152 ) preferably comprise magneto-resistors, such as AMRs, giant-magneto-resistors (such as spin-valves, hereafter SV), or tunneling-magneto-resistors (TMR).
- AMRs magneto-resistors
- giant-magneto-resistors such as spin-valves, hereafter SV
- tunneling-magneto-resistors TMR
- FIG. 9 illustrates a magneto-resistor structure, which can be configured into CIP (current-in-plane, such as a spin-valve) or a CPP (current-perpendicular-to-plane, such as TMR structure).
- CIP current-in-plane
- CPP current-perpendicular-to-plane, such as TMR structure
- the magneto-resistor stack comprises top pin-layer 154 , free-layer 156 , spacer 158 , reference layer 160 , bottom pin layer 162 , and substrate 120 .
- Top pin layer 154 is provided for magnetically pinning free layer 156 .
- the top pin layer can be comprised of IrMn, PtMn or other suitable magnetic materials.
- the free layer ( 156 ) can be comprised of a ferromagnetic material, such as NiFe, CoFe, CoFeB, or other suitable materials or the combinations thereof.
- the spacer ( 158 ) can be comprised of a non-magnetic conductive material, such as Cu, or an oxide material, such as Al 2 O 3 or MgO or other suitable materials.
- the reference layer ( 160 ) can be comprised of a ferromagnetic magnetic material, such as NiFe, CoFe, CoFeB, or other materials or the combinations thereof.
- the bottom pin layer ( 162 ) is provided for magnetic pinning the reference layer ( 160 ), which can be comprised of a IrMn, PtMn or other suitable materials or the combinations thereof.
- the substrate ( 120 ) can be comprised of any suitable materials, such as glass, silicon, or other materials or the combinations thereof.
- the magneto-resistor ( 118 ) stack can be configured into a CIP structure (i.e. spin-valve, SV), wherein the current is driven in the plane of the stack layers.
- the spacer ( 158 ) is comprised of an oxide such as Al 2 O 3 , MgO or the like
- the magneto-resistor stack ( 118 ) can be configured into a CPP structure (i.e. TMR), wherein the current is driven perpendicularly to the stack layers.
- the free layer ( 156 ) is magnetically pinned by the top pin layer ( 154 ), and the reference layer ( 160 ) is also magnetically pinned by bottom pin layer 162 .
- the top pin layer ( 154 ) and the bottom pin layer ( 162 ) preferably having different blocking temperatures.
- a blocking temperature is referred to as the temperature, above which the magnetic pin layer is magnetically decoupled with the associated pinned magnetic layer.
- the top pin layer ( 154 ) is magnetically decoupled with the free layer ( 156 ) above the blocking temperature T B of the top pin layer ( 154 ) such that the free layer ( 156 ) is “freed” from the magnetic pinning of top pin layer ( 154 ).
- the free layer ( 156 ) is magnetically pinned by the top pin layer ( 154 ) such that the magnetic orientation of the free layer ( 156 ) is substantially not affected by the external magnetic field.
- the bottom pin layer ( 162 ) is magnetically decoupled with the reference layer ( 160 ) above the blocking temperature T B of the bottom pin layer ( 162 ) such that the reference layer ( 160 ) is “freed” from the magnetic pinning of bottom pin layer ( 162 ).
- the reference layer ( 160 ) is magnetically pinned by the bottom pin layer ( 162 ) such that the magnetic orientation of the reference layer ( 162 ) is substantially not affected by the external magnetic field.
- the top and bottom pin layers ( 154 and 162 , respectively) preferably have different blocking temperatures.
- the reference layer ( 160 ) preferably remains being pinned by the bottom pin layer ( 162 ).
- the reference layer ( 160 ) can be “freed” from being pinned by the bottom pin layer ( 162 ).
- the reference layer ( 160 ) can be used as a “sensing layer” for responding to the external magnetic field such as the target magnetic field, while the free layer ( 156 ) is used as a reference layer to provide a reference magnetic orientation.
- the different blocking temperatures can be accomplished by using different magnetic materials for the top pin layer ( 154 ) and bottom pin layer ( 162 ).
- the top pin layer ( 154 ) can be comprised of IrMn, while the bottom pin layer ( 162 ) can be comprised of PtMn, vice versa.
- both of the top and bottom pin layers ( 154 and 162 ) may be comprised of the same material, such as IrMn or PtMn, but with different thicknesses such that they have different blocking temperatures.
- the magneto-resistor stack ( 118 ) is configured into sensors for sensing magnetic signals. As such, the magnetic orientations of the free layer ( 156 ) and the reference layer ( 160 ) are substantially perpendicular at the initial state. Other layers, such as protective layer Ta, seed layers for growing the stack layers on substrate 120 can be provided. It is further noted that the magnetic stack layers ( 118 ) illustrated in FIG. 9 are what is often referred to as “bottom pin” configuration in the field of art. In other examples, the stack can be configured into what is often referred as “top pinned” configuration in the field of art, which will not be detailed herein.
- multiple magnetic sensing mechanisms can be provided, an example of which is illustrated in FIG. 10 .
- magnetic sensing mechanisms 116 and 164 are provided for detecting the movements of proof-mass 112 .
- the multiple magnetic sensing mechanisms can be used for detecting the movements of proof-mass 112 in driving mode and sensing mode respectively.
- the multiple magnetic sensing mechanisms 116 and 164 can be provided for detecting the same modes (e.g. the driving mode and/or the sensing mode).
- angular velocity in Z direction causes the motion of the proof-mass in the sensing direction.
- acceleration in the sensing direction also causes the motion of the proof-mass in the sensing direction.
- motion of the proof-mass in the sensing direction is a mixture of both of the angular velocity in the Z direction and acceleration in the sensing direction when both exist.
- the signal measured by the magnetic sensing mechanism is thus a mixture of the signals associated with the proof-mass motion in both directions.
- a solution to separate signals from the angular velocity in Z direction and acceleration in the sensing direction can be provision of multiple proof-masses, an example of which is illustrated in FIG. 11 . It is noted that the example illustrated in FIG. 11 having two proof-masses is only for demonstration purposes. Other variations within the scope of this disclosure are also applicable. For example, more than two proof-masses, such as four or eight proof-masses can be provided in a MEMS gyroscope.
- proof-masses PM 1 170 and PM 2 172 are provided in a MEMS gyroscope.
- the proof-masses ( 170 and 172 ) are connected to anchor 115 through flexures 111 and 113 such that the proof-masses are capable of moving in the driving and sensing directions.
- the proof-masses ( 170 and 172 ) are associated with other mechanical structures to enable the motion of the proof-masses, and those mechanical structures are not shown herein for simplicity.
- Driving mechanisms 117 and 119 are provided for driving the proof-masses ( 170 and 172 ) in their driving modes.
- the driving mechanisms may comprise capacitors or magnetic driving mechanisms or other suitable structures.
- the proof-masses PM 1 and PM 2 move in opposite directions along the driving directions. For example, the proof-masses PM 1 and PM 2 move at the same time toward anchor 115 or at the same time, away from anchor 115 . Because the proof-masses PM 1 and PM 2 have opposite velocities in the driving direction, they also move in opposite directions in the sensing direction under the Coriolis force due to angular velocity in the Z direction. In existence of accelerate in the sensing direction, both of the proof-masses 170 and 172 move in the same direction at the same time. By analyzing the moving directions of the proof-masses 170 and 172 , signals caused by the angular velocity in the Z direction and acceleration in the sensing direction can be separated.
- FIG. 12 illustrates the MEMS substrate of a MEMS gyroscope having multiple proof-masses and using magnetic driving mechanism.
- proof-masses 170 and 172 are formed in MEMS substrate 108 .
- the proof-masses 170 and 172 are connected to and held by anchor 115 through flexures.
- the proof-masses 170 and 172 each are connected to a magnetic driving mechanism.
- proof-mass 170 is connected to movable coil 123 that moves with proof-mass 170 .
- Movable coil 123 is coupled to static coil 121 that is affixed to anchor 125 such that static coil 121 does not move relative to substrate 108 when proof-masses 170 and 172 are moving.
- the coils By driving current in the coupled coils in selected directions, the coils generate attractive and repel forces, as illustrated in FIG. 13 a and FIG. 13 b .
- the direction of the current through movable coil 123 can be fixed, for example counter-clockwise.
- the coils 121 and 123 generate attractive force.
- the static coil ( 121 ) is affixed to anchor 125 and static, the movable coil ( 123 ) is moves towards the static coil ( 121 ) under the attractive force, and so does the proof-mass ( 170 ).
- both of the current in the static coil ( 121 ) and movable coil ( 123 ) have counter-clockwise direction, as illustrated in FIG. 13 bc, the force between the two coils is repellent.
- the movable coil ( 123 ) on does the proof-mass ( 170 ), moves away from the static coil ( 121 ) under the repellent force.
- the proof-mass ( 170 ) can be moved towards and away from the static coil ( 121 ).
- the current direction of the static coil ( 121 ) can be unchanged during operation, while the direction of the current in the movable coil ( 123 ) is varied.
- both of the directions of the current in the static and movable loops can be varied during operation to driving the movable loop, as well as the proof-mass, away and towards the anchor ( 125 ).
- the frequency of changing the current direction can be equal or close to the resonate frequency of the proof-mass in the driving direction. It is noted that multiple static and movable loop pairs can be provided for a proof-mass to increase the driving efficiency, even though FIG. 4 a shows two coil pairs.
- Proof-mass 172 can be driving in the same way as proof-mass 170 by using the magnetic driving mechanism associated therewith. In order to separate signal of the Z direction angular velocity from the acceleration in the sensing direction, proof-masses 170 and 172 are driving in opposite directions in the sensing mode as discussed above with reference to FIG. 11 , which will not be repeated herein.
- Proof-mass 170 is provided with a conducting wire ( 174 ) as a magnetic field source for generating magnetic field.
- the conducting wire ( 174 ) can be formed at the bottom surface of proof-mass 170 as discussed above with reference to FIG. 3 .
- magnetic sensor 176 Associated with conducting wire 170 is magnetic sensor 176 for measuring the magnetic field from conducting wire 174 .
- the magnetic sensor ( 176 ) is formed on sensor substrate 110 as shown in FIG. 3 .
- the magnetic sensor 176 can be the same as magnetic sensor 118 as discussed above with reference to FIG. 3 .
- magnetic sensor 176 when comprised of a solid-state spintronic structure, such as a spin-valve or magnetic-tunnel-junction, can be offset from conducting wire 174 along the direction of the sensing mode. Specifically, the geometric center of magnetic sensor 176 is offset from the closest conducting wire passing by. Similar to that for proof-mass 170 , proof-mass 172 is provided with conducting wire 178 and associated sensing mechanism 180 , which will not be repeated herein.
- the MEMS gyroscope as discussed above with reference to FIG. 3 can have multiple proof-masses and capacitive driving mechanisms, an example of which is illustrated in FIG. 15 .
- proof-masses 170 and 172 are provided.
- the proof-masses are driven by capacitive combs.
- proof-mass 170 is connected to one set of capacitive plates of a capacitor comb; and the other set of capacitor plates 10 are connected to anchor 127 .
- electrostatic force can be generated.
- the electrostatic force drives proof-mass 170 to move in the driving direction.
- proof-mass 172 is also connected to a set of capacitor plates; and the other set of capacitor plates of a capacitor comb is connected to an anchor. By changing the voltages between the plates, proof-mass 172 can be moved under electrostatic force caused by the variation of the voltage.
- the capacitor combs associated with proof-masses 170 and 172 are operated asynchronously such that proof-masses 170 and 172 move in opposite directions along the driving direction. In response to the same angular velocity in Z direction, proof-masses 170 and 172 move in opposite directions along the sensing direction.
- a proof-mass of a MEMS gyroscope may have multiple magnetic sources, an example of which is illustrated in FIG. 16 a .
- the MEMS gyroscope comprises proof-masses 170 and 172 .
- At least one of the proof-masses 170 and 172 comprises multiple magnetic sources.
- proof-mass 170 is attached thereto conducting wires 14 , 24 and 16 , each of which is capable of generating magnetic field.
- the conducting wires can be serially connected as shown in FIG. 16 a .
- a magnetic sensor is provided but on the sensor substrate, which is illustrated as blocks with dotted lines.
- magnetic sensors 22 , 20 and 18 are associated with and aligned to conducting wires 14 , 24 and 16 separately. By placing the conducting wires with distances larger than the sensitivity of the magnetic sensors, magnetic field signals from neighboring wires may not be measured by a magnetic sensor.
- the multiple magnetic source configuration can be of great value especially when multiple magnetic sensors are desired, such as Wheatstone bridge configuration.
- magnetic sensor 22 which can be a spin-valve or a magnetic-tunnel-junction (MTJ) or other spintronic devices, has an (magnetic) easy axis along its length and (magnetic) hard axis along its width, wherein the easy and hard axes are often perpendicular.
- the easy axis of magnetic sensor 22 is substantially parallel to the driving direction (the direction of the driving mode); and the hard axis is substantially parallel to the sensing direction (direction of the sensing mode).
- the current is in the direction along the length, and thus the easy axis of the magnetic sensor 22 . This is because the current through wire 14 generates magnetic field. This magnetic field has much higher magnetic gradient along the width of the magnetic sensor ( 22 ). Aligning the hard axis of magnetic sensor 22 to the direction having higher magnetic gradient (i.e. the sensing direction) benefits the higher sensitivity, and thus the performance of the MEMS gyroscope.
- a reference magnetic sensor is often provided for providing reference signals.
- the measured magnetic signals from magnetic sensors can be compared with the reference signals followed by amplification.
- each magnetic sensor e.g. 22 , 20 , and 18
- the reference sensors are often identical in terms of structures, but are isolated from external magnetic field by being covered by a magnetic insulation layer, such as a soft magnetic material.
- a reference sensor can be provided for multiple magnetic sensors associated with a proof-mass, as illustrated in FIG. 17 .
- magnetic sensors 18 , 20 , and 22 are provided for measuring magnetic field from magnetic sources 16 , 24 , and 14 respectively.
- the magnetic sources 14 , 24 , and 16 are attached to proof-mass 170 for measuring movements of proof-mass 170 .
- Reference sensor 26 is provided for magnetic sensors 18 , 20 , and 22 .
- the reference sensor ( 26 ) is substantially the same as magnetic sensors 18 , 20 , and 22 , but is magnetically insulated by being covered with a magnetic insulation layer such that reference sensor 26 is not responsive to external magnetic field.
- the measured magnetic signals from magnetic sensors 18 , 20 , and 22 are compared with the output signal form the reference sensor ( 26 ), and the output of the comparison can be amplified.
- the reference sensor ( 26 ) can be placed at any suitable location in the vicinity of the magnetic sensors 18 , 20 , and 22 . In the example as illustrated in FIG. 17 , the reference sensor ( 26 ) can be placed in the vicinity of magnetic sensor ( 18 ). It is noted by those skilled in the art that even though a reference sensor is provided for a proof-mass, such as proof-mass 170 , other proof-masses, such as proof-mass 172 may or may not be provided with a reference sensor.
- magnetic sensing mechanism for measuring magnetic field can be integrated in a sensor substrate, such as sensor substrate 110 .
- the multiple sensors can use one or more reference magnetic sensor as reference signals.
- the multiple sensors can take a form of Wheatstone bridge, in which example, four or more magnetic sensors are provided to improve the accuracy of the measurements.
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Remote Sensing (AREA)
- Radar, Positioning & Navigation (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Signal Processing (AREA)
- Computer Hardware Design (AREA)
- Manufacturing & Machinery (AREA)
- Micromachines (AREA)
- Gyroscopes (AREA)
- Hall/Mr Elements (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
A MEMS gyroscope is disclosed herein, wherein the MEMS gyroscope comprises a movable portion capable of moving in response to angular velocity, a conducting wire attached to the movable portion for generating magnetic field, and a spintronic device for measuring the magnetic field. The easy axis of the spintronic device is aligned to the sensing mode of the movable portion and to the direction of the current flowing through the conducting wire.
Description
- This US utility patent application claims priority from co-pending US utility patent application “A HYBRID MEMS DEVICE,” Ser. No. 13/559,625 filed Jul. 27, 2012, which claims priority from US provisional patent application “A HYBRID MEMS DEVICE,” filed May 31, 2012, Ser. No. 61/653,408 to Biao Zhang and Tao Ju. This US utility patent application also claims priority from co-pending US utility patent application “A MEMS DEVICE,” Ser. No. 13/854,972 filed Apr. 2, 2013 to the same inventor of this US utility patent application, the subject matter of each of which is incorporated herein by reference in its entirety.
- The technical field of the examples to be disclosed in the following sections is related generally to the art of operation of microstructures, and, more particularly, to operation of MEMS devices comprising MEMS magnetic sensing structures.
- Microstructures, such as microelectromechanical (hereafter MEMS) devices (e.g. accelerometers, DC relay and RF switches, optical cross connects and optical switches, microlenses, reflectors and beam splitters, filters, oscillators and antenna system components, variable capacitors and inductors, switched banks of filters, resonant comb-drives and resonant beams, and micromirror arrays for direct view and projection displays) have many applications in basic signal transduction. For example, a MEMS gyroscope measures angular rate.
- A gyroscope (hereafter “gyro” or “gyroscope”) is based on the Coriolis effect as diagrammatically illustrated in
FIG. 1 . Proof-mass 100 is moving with velocity Vd. Under external angular velocity Ω, the Coriolis effect causes movement of the poof-mass (100) with velocity Vs. With fixed Vd, the external angular velocity can be measured from Vd. A typical example based on the theory shown inFIG. 1 is capacitive MEMS gyroscope, as diagrammatically illustrated inFIG. 2 . - The MEMS gyro is a typical capacitive MEMS gyro, which has been widely studied. Regardless of various structural variations, the capacitive MEMS gyro in
FIG. 2 includes the very basic theory based on which all other variations are built. In this typical structure,capacitive MEMS gyro 102 is comprised of proof-mass 100,driving mode 104, andsensing mode 102. The driving mode (104) causes the proof-mass (100) to move in a predefined direction, and such movement is often in a form of resonance vibration. Under external angular rotation, the proof-mass (100) also moves along the Vs direction with velocity Vs. Such movement of Vs is detected by the capacitor structure of the sensing mode (102). Both of the driving and sensing modes use capacitive structures, whereas the capacitive structure of the driving mode changes the overlaps of the capacitors, and the capacitive structure of the sensing mode changes the gaps of the capacitors. - Current capacitive MEMS gyros, however, are hard to achieve submicro-g/rtHz because the capacitance between sensing electrodes decreases with the miniaturization of the movable structure of the sensing element and the impact of the stray and parasitic capacitance increase at the same time, even with large and high aspect ratio proof-masses.
- Therefore, what is desired is a MEMS device capable of sensing angular velocities and methods of operating the same.
- In view of the foregoing, a MEMS gyroscope is disclosed herein, wherein the gyroscope comprises: a first substrate, comprising: a pair of movable portions that are capable of moving in opposite directions in response to an angular velocity along a sensing direction; a pair of driving mechanisms associated with said movable portions for moving the movable portions in opposite directions along a driving direction that is substantially perpendicular to the sensing direction; a plurality of magnetic sources attached to at least one of the movable portions for generating magnetic field; and a reference sensor associated with said plurality of magnetic sensors for providing a reference signal; and a second substrate having a plurality of magnetic sensors that are a spintronic device for measuring the magnetic field from the conducting wire, wherein the magnetic sensors form a part of a Wheatstone bridge.
-
FIG. 1 diagrammatically illustrates the Coriolis effect in a MEMS structure; -
FIG. 2 is a top view of a typical existing capacitive MEMS gyroscope having a driving mode and a sensing mode, wherein both of the driving and sensing mode utilize capacitance structures; -
FIG. 3 illustrates an exemplary MEMS gyroscope having a magnetic sensing mechanism; -
FIG. 4 illustrates a top view of a portion of an exemplary implementation of the MEMS gyroscope illustrated inFIG. 3 , wherein the MEMS gyroscope illustrated inFIG. 4 having a capacitive driving mode and a magnetic sensing mechanism; -
FIG. 5 illustrates a perspective view of a portion of another exemplary implementation of the MEMS gyroscope illustrated inFIG. 3 , wherein the MEMS gyroscope illustrated inFIG. 5 having a magnetic driving mechanism for the driving mode and a magnetic sensing mechanism for the sensing mode -
FIG. 6 illustrates an exemplary magnetic driving mechanism of the MEMS gyroscope inFIG. 5 ; -
FIG. 7 illustrates an exemplary magnetic source of the MEMS gyroscope illustrated inFIG. 3 ; -
FIG. 8 illustrates an exemplary magnetic sensing mechanism that can be used in the MEMS gyroscope illustrated inFIG. 3 ; -
FIG. 9 shows an exemplary thin-film stack that can be configured into a CIP or CPP structure for use in the magnetic sensing mechanism illustrated inFIG. 8 ; -
FIG. 10 illustrates an exemplary MEMS gyroscope that comprises multiple magnetic sensing structures; -
FIG. 11 illustrates an exemplary MEMS gyroscope that comprises multiple proof-masses; -
FIG. 12 illustrates an exemplary MEMS gyroscope that comprises multiple proof-masses having magnetic driving mechanisms; -
FIG. 13a andFIG. 13b illustrate an exemplary driving scheme for use in the MEMS gyroscope illustrated inFIG. 12 ; -
FIG. 14 illustrates an exemplary magnetic source and magnetic sensing mechanism of the MEMS gyroscope illustrated inFIG. 13 ; -
FIG. 15 illustrates another exemplary MEMS gyroscope that comprises multiple proof-masses having capacitive driving mechanisms; -
FIG. 16a andFIG. 16b illustrate yet another exemplary MEMS gyroscope comprising multiple proof-masses and multiple magnetic sources in at least one of the proof-masses; and -
FIG. 17 illustrates yet another exemplary MEMS gyroscope comprising multiple proof-masses, multiple magnetic sources in at least one of the proof-masses, and a reference magnetic sensor for the multiple magnetic sensors. - Disclosed herein is a MEMS gyroscope for sensing an angular velocity, wherein the MEMS gyroscope utilizes a magnetic sensing mechanism. It will be appreciated by those skilled in the art that the following discussion is for demonstration purposes, and should not be interpreted as a limitation. Many other variations within the scope of the following disclosure are also applicable. For example, the MEMS gyroscope and the method disclosed in the following are applicable for use in accelerometers.
- Referring to
FIG. 3 , an exemplary MEMS gyroscope is illustrated herein. In this example,MEMS gyroscope 106 comprisesmagnetic sensing mechanism 114 for sensing the target angular velocity through the measurement of proof-mass 112. Specifically,MEMS gyroscope 106 comprises mass-substrate 108 andsensor substrate 110. Mass-substrate 108 comprises proof-mass 112 that is capable of responding to an angular velocity. The two substrates (108 and 110) are spaced apart, for example, by a pillar (not shown herein for simplicity) such that at least the proof-mass (112) is movable in response to an angular velocity under the Coriolis effect. The movement of the proof-mass (112) and thus the target angular velocity can be measured bymagnetic sensing mechanism 114. - The magnetic sensing mechanism (114) in this example comprises a
magnetic source 116 andmagnetic sensor 118. The magnetic source (116) generates a magnetic field, and the magnetic sensor (118) detects the magnetic field and/or the magnetic field variations that is generated by the magnetic source (116). In the example illustrated herein inFIG. 3 , the magnetic source is placed on/in the proof-mass (112) and moves with the proof-mass (112). The magnetic sensor (118) is placed on/in the sensor substrate (120) and non-movable relative to the moving proof-mass (112) and the magnetic source (116). With this configuration, the movement of the proof-mass (112) can be measured from the measurement of the magnetic field from the magnetic source (116). - Other than placing the magnetic source on/in the movable proof-mass (1112), the magnetic source (116) can be placed on/in the sensor substrate (120); and the magnetic sensor (118) can be placed on/in the proof-mass (112).
- It is also noted that the MEMS gyroscope illustrated in
FIG. 3 can also be used as an accelerometer. - The MEMS gyroscope as discussed above with reference to
FIG. 3 can be implemented in many ways, one of which is illustrated inFIG. 4 . Referring toFIG. 4 , the proof-mass (120) is driven by capacitive, such as capacitive comb. The sensing mode, however, is performed using the magnetic sensing mechanism illustrated inFIG. 3 . For this reason, capacitive combs can be absent from the proof-mass (120). - Alternatively, the proof-mass can be driven by magnetic force, an example of which is illustrated in
FIG. 5 . Referring toFIG. 5 , the mass substrate (108) comprises a movable proof-mass (126) that is supported by flexible structures such asflexures mass substrate 108. In particular, the flexures enables the proof-mass to move along the length and the width directions, wherein the length direction can be the driving mode direction and the width direction can be the sensing mode direction of the MEMS gyro device. The proof-mass (126) is connected to frame 132 through flexures (128, 129, and 130). The frame (132) is anchored by non-movable structures such aspillar 134. The mass-substrate (108) andsensing substrate 110 are spaced apart by the pillar (134). The proof-mass (112) in this example is driving by a magnetic driving mechanism (136). Specifically, the proof-mass (126) can move (e.g. vibrate) in the driving mode under magnetic force applied bymagnetic driving mechanism 136, which is better illustrated inFIG. 6 . - Referring to
FIG. 6 , themagnetic driving mechanism 136 comprise amagnet core 138 surrounded bycoil 140. By applying an alternating current throughcoil 140, an alternating magnetic field can be generated from thecoil 140. The alternating magnetic field applies magnetic force to themagnet core 140 so as to move the magnet core. The magnet core thus moves the proof-mass. - The magnetic source (114) of the MEMS gyroscope (106) illustrated in
FIG. 3 can be implemented in many ways, one of which is illustrated inFIG. 7 . Referring toFIG. 7 ,conductive wire 142 is displaced on/in proof-mass 112. In one example,conductive wire 142 can be placed on the lower surface of the proof-mass (112), wherein the lower surface is facing the magnetic sensors (118 inFIG. 3 ) on the sensor substrate (110, inFIG. 3 ). Alternatively, the conductive wire (142) can be placed on the top surface of the proof-mass (112), i.e. on the opposite side of the proof-mass (112) in view of the magnetic sensor (118). In another example, the conductive wire (142) can be placed inside the proof-mass, e.g. laminated or embedded inside the proof-mass (112), which will not be detailed herein as those examples are obvious to those skilled in the art of the related technical field. - The conductive wire (142) can be implemented in many suitable ways, one of which is illustrated in
FIG. 7 . In this example, the conductive wire (142) comprises a centerconductive segment 146 and taperedcontacts - The magnetic sensor (118) illustrated in
FIG. 3 can be implemented to comprise a reference sensor (150) and a signal sensor (152) as illustrated inFIG. 8 . Referring toFIG. 8 ,magnetic senor 118 on/insensor substrate 120 comprisesreference sensor 150 andsignal sensor 152. The reference sensor (150) can be designated for dynamically measuring the magnetic signal background in which the target magnetic signal (e.g. the magnetic field from theconductive wire 146 as illustrated inFIG. 7 ) co-exists. The signal sensor (152) can be designated for dynamically measuring the target magnetic signal (e.g. the magnetic field from theconductive wire 146 as illustrated inFIG. 7 ). In other examples, the signal sensor (152) can be designated for dynamically measuring the magnetic signal background in which the target magnetic signal (e.g. the magnetic field from theconductive wire 146 as illustrated inFIG. 7 ) co-exists, while the signal sensor (150) can be designated for dynamically measuring the target magnetic signal (e.g. the magnetic field from theconductive wire 146 as illustrated inFIG. 7 ). - The reference sensor (150) and the signal sensor (152) preferably comprise magneto-resistors, such as AMRs, giant-magneto-resistors (such as spin-valves, hereafter SV), or tunneling-magneto-resistors (TMR). For demonstration purpose,
FIG. 9 illustrates a magneto-resistor structure, which can be configured into CIP (current-in-plane, such as a spin-valve) or a CPP (current-perpendicular-to-plane, such as TMR structure). As illustrated inFIG. 9 , the magneto-resistor stack comprises top pin-layer 154, free-layer 156,spacer 158,reference layer 160,bottom pin layer 162, andsubstrate 120.Top pin layer 154 is provided for magnetically pinningfree layer 156. The top pin layer can be comprised of IrMn, PtMn or other suitable magnetic materials. The free layer (156) can be comprised of a ferromagnetic material, such as NiFe, CoFe, CoFeB, or other suitable materials or the combinations thereof. The spacer (158) can be comprised of a non-magnetic conductive material, such as Cu, or an oxide material, such as Al2O3 or MgO or other suitable materials. The reference layer (160) can be comprised of a ferromagnetic magnetic material, such as NiFe, CoFe, CoFeB, or other materials or the combinations thereof. The bottom pin layer (162) is provided for magnetic pinning the reference layer (160), which can be comprised of a IrMn, PtMn or other suitable materials or the combinations thereof. The substrate (120) can be comprised of any suitable materials, such as glass, silicon, or other materials or the combinations thereof. - In examples wherein the spacer (158) is comprised of a non-magnetic conductive layer, such as Cu, the magneto-resistor (118) stack can be configured into a CIP structure (i.e. spin-valve, SV), wherein the current is driven in the plane of the stack layers. When the spacer (158) is comprised of an oxide such as Al2O3, MgO or the like, the magneto-resistor stack (118) can be configured into a CPP structure (i.e. TMR), wherein the current is driven perpendicularly to the stack layers.
- In the example as illustrated in
FIG. 9 , the free layer (156) is magnetically pinned by the top pin layer (154), and the reference layer (160) is also magnetically pinned bybottom pin layer 162. The top pin layer (154) and the bottom pin layer (162) preferably having different blocking temperatures. In this specification, a blocking temperature is referred to as the temperature, above which the magnetic pin layer is magnetically decoupled with the associated pinned magnetic layer. For example, the top pin layer (154) is magnetically decoupled with the free layer (156) above the blocking temperature TB of the top pin layer (154) such that the free layer (156) is “freed” from the magnetic pinning of top pin layer (154). Equal to or below the blocking temperature TB of the top pin layer (154), the free layer (156) is magnetically pinned by the top pin layer (154) such that the magnetic orientation of the free layer (156) is substantially not affected by the external magnetic field. Similarly, the bottom pin layer (162) is magnetically decoupled with the reference layer (160) above the blocking temperature TB of the bottom pin layer (162) such that the reference layer (160) is “freed” from the magnetic pinning of bottom pin layer (162). Equal to or below the blocking temperature TB of the bottom pin layer (162), the reference layer (160) is magnetically pinned by the bottom pin layer (162) such that the magnetic orientation of the reference layer (162) is substantially not affected by the external magnetic field. - The top and bottom pin layers (154 and 162, respectively) preferably have different blocking temperatures. When the free layer (156) is “freed” from being pinned by the top pin layer (154), the reference layer (160) preferably remains being pinned by the bottom pin layer (162). Alternatively, when the free layer (156) is still pinned by the top pin layer (154), the reference layer (160) can be “freed” from being pinned by the bottom pin layer (162). In the later example, the reference layer (160) can be used as a “sensing layer” for responding to the external magnetic field such as the target magnetic field, while the free layer (156) is used as a reference layer to provide a reference magnetic orientation.
- The different blocking temperatures can be accomplished by using different magnetic materials for the top pin layer (154) and bottom pin layer (162). In one example, the top pin layer (154) can be comprised of IrMn, while the bottom pin layer (162) can be comprised of PtMn, vice versa. In another example, both of the top and bottom pin layers (154 and 162) may be comprised of the same material, such as IrMn or PtMn, but with different thicknesses such that they have different blocking temperatures.
- It is noted by those skilled in the art that the magneto-resistor stack (118) is configured into sensors for sensing magnetic signals. As such, the magnetic orientations of the free layer (156) and the reference layer (160) are substantially perpendicular at the initial state. Other layers, such as protective layer Ta, seed layers for growing the stack layers on
substrate 120 can be provided. It is further noted that the magnetic stack layers (118) illustrated inFIG. 9 are what is often referred to as “bottom pin” configuration in the field of art. In other examples, the stack can be configured into what is often referred as “top pinned” configuration in the field of art, which will not be detailed herein. - In some applications, multiple magnetic sensing mechanisms can be provided, an example of which is illustrated in
FIG. 10 . Referring toFIG. 10 ,magnetic sensing mechanisms mass 112. The multiple magnetic sensing mechanisms can be used for detecting the movements of proof-mass 112 in driving mode and sensing mode respectively. Alternatively, the multiplemagnetic sensing mechanisms - In operation, angular velocity in Z direction (perpendicular to the driving and sensing direction) causes the motion of the proof-mass in the sensing direction. However, acceleration in the sensing direction also causes the motion of the proof-mass in the sensing direction. As a consequence, motion of the proof-mass in the sensing direction is a mixture of both of the angular velocity in the Z direction and acceleration in the sensing direction when both exist. The signal measured by the magnetic sensing mechanism is thus a mixture of the signals associated with the proof-mass motion in both directions. A solution to separate signals from the angular velocity in Z direction and acceleration in the sensing direction can be provision of multiple proof-masses, an example of which is illustrated in
FIG. 11 . It is noted that the example illustrated inFIG. 11 having two proof-masses is only for demonstration purposes. Other variations within the scope of this disclosure are also applicable. For example, more than two proof-masses, such as four or eight proof-masses can be provided in a MEMS gyroscope. - Referring to
FIG. 11 , proof-masses PM1 170 andPM2 172 are provided in a MEMS gyroscope. The proof-masses (170 and 172) are connected to anchor 115 throughflexures mechanisms - To separate the angular velocity in the Z direction and acceleration in the sensing direction, the proof-masses PM1 and PM2 move in opposite directions along the driving directions. For example, the proof-masses PM1 and PM2 move at the same time toward
anchor 115 or at the same time, away fromanchor 115. Because the proof-masses PM1 and PM2 have opposite velocities in the driving direction, they also move in opposite directions in the sensing direction under the Coriolis force due to angular velocity in the Z direction. In existence of accelerate in the sensing direction, both of the proof-masses masses - As an example,
FIG. 12 illustrates the MEMS substrate of a MEMS gyroscope having multiple proof-masses and using magnetic driving mechanism. Referring toFIG. 12 , proof-masses MEMS substrate 108. The proof-masses anchor 115 through flexures. The proof-masses mass 170 is connected tomovable coil 123 that moves with proof-mass 170.Movable coil 123 is coupled tostatic coil 121 that is affixed to anchor 125 such thatstatic coil 121 does not move relative tosubstrate 108 when proof-masses - By driving current in the coupled coils in selected directions, the coils generate attractive and repel forces, as illustrated in
FIG. 13a andFIG. 13b . Referring toFIG. 13 a, the direction of the current throughmovable coil 123 can be fixed, for example counter-clockwise. When the current instatic coil 121 has a clockwise direction, thecoils FIG. 13 bc, the force between the two coils is repellent. The movable coil (123), on does the proof-mass (170), moves away from the static coil (121) under the repellent force. - By changing the direction of the current in the static coil while keeping the current direction in the movable coil unchanged, the proof-mass (170) can be moved towards and away from the static coil (121). In other examples, the current direction of the static coil (121) can be unchanged during operation, while the direction of the current in the movable coil (123) is varied. In another example, both of the directions of the current in the static and movable loops can be varied during operation to driving the movable loop, as well as the proof-mass, away and towards the anchor (125). In any examples, the frequency of changing the current direction can be equal or close to the resonate frequency of the proof-mass in the driving direction. It is noted that multiple static and movable loop pairs can be provided for a proof-mass to increase the driving efficiency, even though
FIG. 4a shows two coil pairs. - Proof-
mass 172 can be driving in the same way as proof-mass 170 by using the magnetic driving mechanism associated therewith. In order to separate signal of the Z direction angular velocity from the acceleration in the sensing direction, proof-masses FIG. 11 , which will not be repeated herein. - For detecting the motion of the proof-masses (170 and 172), multiple magnetic sensing mechanisms are provided, and example of which is illustrated in
FIG. 14 . Referring toFIG. 14 , Proof-mass 170 is provided with a conducting wire (174) as a magnetic field source for generating magnetic field. The conducting wire (174) can be formed at the bottom surface of proof-mass 170 as discussed above with reference toFIG. 3 . Associated withconducting wire 170 ismagnetic sensor 176 for measuring the magnetic field from conductingwire 174. The magnetic sensor (176) is formed onsensor substrate 110 as shown inFIG. 3 . Themagnetic sensor 176 can be the same asmagnetic sensor 118 as discussed above with reference toFIG. 3 . It is noted thatmagnetic sensor 176, when comprised of a solid-state spintronic structure, such as a spin-valve or magnetic-tunnel-junction, can be offset from conductingwire 174 along the direction of the sensing mode. Specifically, the geometric center ofmagnetic sensor 176 is offset from the closest conducting wire passing by. Similar to that for proof-mass 170, proof-mass 172 is provided withconducting wire 178 and associatedsensing mechanism 180, which will not be repeated herein. - In yet another example, the MEMS gyroscope as discussed above with reference to
FIG. 3 can have multiple proof-masses and capacitive driving mechanisms, an example of which is illustrated inFIG. 15 . Referring toFIG. 15 , proof-masses mass 170 is connected to one set of capacitive plates of a capacitor comb; and the other set ofcapacitor plates 10 are connected to anchor 127. By changing the voltage between the capacitive plates, electrostatic force can be generated. The electrostatic force drives proof-mass 170 to move in the driving direction. - Similar to proof-
mass 170, proof-mass 172 is also connected to a set of capacitor plates; and the other set of capacitor plates of a capacitor comb is connected to an anchor. By changing the voltages between the plates, proof-mass 172 can be moved under electrostatic force caused by the variation of the voltage. - The same to that in magnetic driving scheme as discussed above with reference to
FIG. 14 , the capacitor combs associated with proof-masses masses masses - Regardless of driving mechanisms, a proof-mass of a MEMS gyroscope may have multiple magnetic sources, an example of which is illustrated in
FIG. 16a . Referring toFIG. 16a , the MEMS gyroscope comprises proof-masses masses mass 170 is attached thereto conductingwires FIG. 16a . Associated with each conducting wire, a magnetic sensor is provided but on the sensor substrate, which is illustrated as blocks with dotted lines. For example,magnetic sensors wires - In operation, current is driven through conducting
wires - It is noted that the magnetic sensors (18, 20, and 22) are aligned to the conducting
wires magnetic sensor 22 for example as illustrated inFIG. 16b ,magnetic sensor 22, which can be a spin-valve or a magnetic-tunnel-junction (MTJ) or other spintronic devices, has an (magnetic) easy axis along its length and (magnetic) hard axis along its width, wherein the easy and hard axes are often perpendicular. The easy axis ofmagnetic sensor 22 is substantially parallel to the driving direction (the direction of the driving mode); and the hard axis is substantially parallel to the sensing direction (direction of the sensing mode). The current is in the direction along the length, and thus the easy axis of themagnetic sensor 22. This is because the current throughwire 14 generates magnetic field. This magnetic field has much higher magnetic gradient along the width of the magnetic sensor (22). Aligning the hard axis ofmagnetic sensor 22 to the direction having higher magnetic gradient (i.e. the sensing direction) benefits the higher sensitivity, and thus the performance of the MEMS gyroscope. - It will be appreciated by those skilled in the art that the configuration as discussed above with reference to
FIG. 6b is also applicable to other MEMS gyroscopes, such as MEMS gyroscopes having one proof-mass, and MEMS gyroscopes having more than two proof-masses, which will not be detailed herein due to their obviousness. - In examples using spintronic magnetic sensors such as spin-valves or magnetic-tunnel-junctions, a reference magnetic sensor is often provided for providing reference signals. The measured magnetic signals from magnetic sensors can be compared with the reference signals followed by amplification. In the example as shown in
FIG. 16a , each magnetic sensor (e.g. 22, 20, and 18) can be associated with a reference sensor. The reference sensors are often identical in terms of structures, but are isolated from external magnetic field by being covered by a magnetic insulation layer, such as a soft magnetic material. In yet another example, a reference sensor can be provided for multiple magnetic sensors associated with a proof-mass, as illustrated inFIG. 17 . - Referring to
FIG. 17 ,magnetic sensors magnetic sources magnetic sources mass 170 for measuring movements of proof-mass 170.Reference sensor 26 is provided formagnetic sensors magnetic sensors reference sensor 26 is not responsive to external magnetic field. - The measured magnetic signals from
magnetic sensors magnetic sensors FIG. 17 , the reference sensor (26) can be placed in the vicinity of magnetic sensor (18). It is noted by those skilled in the art that even though a reference sensor is provided for a proof-mass, such as proof-mass 170, other proof-masses, such as proof-mass 172 may or may not be provided with a reference sensor. - As can be seen from the above discussion, magnetic sensing mechanism for measuring magnetic field, and thus the motion of the proof-mass can be integrated in a sensor substrate, such as
sensor substrate 110. When multiple magnetic sensors are provided, the multiple sensors can use one or more reference magnetic sensor as reference signals. Alternatively, the multiple sensors can take a form of Wheatstone bridge, in which example, four or more magnetic sensors are provided to improve the accuracy of the measurements. - It will be appreciated by those of skilled in the art that a new and useful MEMS gyroscope has been described herein. In view of the many possible embodiments, however, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of what is claimed. Those of skill in the art will recognize that the illustrated embodiments can be modified in arrangement and detail. Therefore, the devices and methods as described herein contemplate all such embodiments as may come within the scope of the following claims and equivalents thereof. In the claims, only elements denoted by the words “means for” are intended to be interpreted as means plus function claims under 35 U.S.C. §112, the sixth paragraph.
Claims (5)
1. A MEMS gyroscope, comprising:
a first substrate, comprising:
a movable portion that is capable of moving in response to an angular velocity;
a driving mechanism associated with said movable portion for moving the movable portion along a driving direction in a driving mode;
a conducting wire of a magnetic source on the movable portion for generating magnetic field; and
a second substrate, comprising:
a plurality of magnetic sensors that are a spintronic device for measuring the magnetic field from the conducting wire, wherein the magnetic sensors form a part of a Wheatstone bridge.
2. The MEMS gyroscope of claim 1 , wherein the spintronic device comprises a spin-valve.
3. The MEMS gyroscope of claim 1 , wherein the spintronic device comprises a tunnel-magnetic-resistor.
4. The MEMS gyroscope of claim 1 , wherein the driving mechanism comprises a group of capacitors;
5. The MEMS gyroscope of claim 1 , wherein the driving mechanism comprises a magnetic driving mechanism.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/518,607 US20160153780A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201213559625A | 2012-07-27 | 2012-07-27 | |
US13/854,972 US20140290365A1 (en) | 2013-04-02 | 2013-04-02 | Mems device |
US14/518,607 US20160153780A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US201213559625A Continuation | 2012-05-31 | 2012-07-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20160153780A1 true US20160153780A1 (en) | 2016-06-02 |
Family
ID=49993560
Family Applications (14)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/935,557 Abandoned US20140026658A1 (en) | 2012-07-27 | 2013-07-05 | Mems device and a method of using the same |
US13/935,558 Abandoned US20140026659A1 (en) | 2012-07-27 | 2013-07-05 | Mems device and a method of using the same |
US13/936,143 Abandoned US20140190257A1 (en) | 2012-07-27 | 2013-07-06 | Mems device and a method of using the same |
US13/936,145 Abandoned US20140026661A1 (en) | 2012-07-27 | 2013-07-06 | Mems device |
US13/936,144 Abandoned US20140026660A1 (en) | 2012-07-27 | 2013-07-06 | Mems device |
US14/178,229 Abandoned US20150226555A1 (en) | 2012-07-27 | 2014-02-11 | Mems gyroscope |
US14/512,469 Abandoned US20160154070A1 (en) | 2012-07-27 | 2014-10-13 | Wafer bonding method for use in making a mems gyroscope |
US14/518,665 Abandoned US20150033856A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,621 Abandoned US20160154019A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,355 Abandoned US20150033854A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,651 Abandoned US20150033855A1 (en) | 2012-07-27 | 2014-10-20 | Mems device |
US14/518,712 Abandoned US20160154020A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,607 Abandoned US20160153780A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,688 Expired - Fee Related US10012670B2 (en) | 2012-07-27 | 2014-10-20 | Wafer bonding method for use in making a MEMS gyroscope |
Family Applications Before (12)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US13/935,557 Abandoned US20140026658A1 (en) | 2012-07-27 | 2013-07-05 | Mems device and a method of using the same |
US13/935,558 Abandoned US20140026659A1 (en) | 2012-07-27 | 2013-07-05 | Mems device and a method of using the same |
US13/936,143 Abandoned US20140190257A1 (en) | 2012-07-27 | 2013-07-06 | Mems device and a method of using the same |
US13/936,145 Abandoned US20140026661A1 (en) | 2012-07-27 | 2013-07-06 | Mems device |
US13/936,144 Abandoned US20140026660A1 (en) | 2012-07-27 | 2013-07-06 | Mems device |
US14/178,229 Abandoned US20150226555A1 (en) | 2012-07-27 | 2014-02-11 | Mems gyroscope |
US14/512,469 Abandoned US20160154070A1 (en) | 2012-07-27 | 2014-10-13 | Wafer bonding method for use in making a mems gyroscope |
US14/518,665 Abandoned US20150033856A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,621 Abandoned US20160154019A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,355 Abandoned US20150033854A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
US14/518,651 Abandoned US20150033855A1 (en) | 2012-07-27 | 2014-10-20 | Mems device |
US14/518,712 Abandoned US20160154020A1 (en) | 2012-07-27 | 2014-10-20 | Mems gyroscope |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US14/518,688 Expired - Fee Related US10012670B2 (en) | 2012-07-27 | 2014-10-20 | Wafer bonding method for use in making a MEMS gyroscope |
Country Status (1)
Country | Link |
---|---|
US (14) | US20140026658A1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111413653A (en) * | 2019-01-07 | 2020-07-14 | 中国科学院上海微系统与信息技术研究所 | Magnetic field sensor structure and preparation method thereof |
US10802087B2 (en) | 2018-09-11 | 2020-10-13 | Honeywell International Inc. | Spintronic accelerometer |
US10871529B2 (en) | 2018-09-11 | 2020-12-22 | Honeywell International Inc. | Spintronic mechanical shock and vibration sensor device |
US10876839B2 (en) | 2018-09-11 | 2020-12-29 | Honeywell International Inc. | Spintronic gyroscopic sensor device |
US11054438B2 (en) | 2019-03-29 | 2021-07-06 | Honeywell International Inc. | Magnetic spin hall effect spintronic accelerometer |
US20220178692A1 (en) * | 2017-12-21 | 2022-06-09 | Mindmaze Holding Sa | System, method and apparatus of a motion sensing stack with a camera system |
Families Citing this family (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9254992B2 (en) * | 2012-07-27 | 2016-02-09 | Tao Ju | Method of making a MEMS gyroscope having a magnetic source and a magnetic sensing mechanism |
CN103728467B (en) * | 2012-10-16 | 2016-03-16 | 无锡华润上华半导体有限公司 | Plane-parallel capacitor |
US9513346B2 (en) * | 2014-01-07 | 2016-12-06 | Invensense, Inc. | Magnetic sensors with permanent magnets magnetized in different directions |
US9513347B2 (en) * | 2013-10-31 | 2016-12-06 | Invensense, Inc. | Device with magnetic sensors with permanent magnets |
US9296606B2 (en) * | 2014-02-04 | 2016-03-29 | Invensense, Inc. | MEMS device with a stress-isolation structure |
DE102014109701A1 (en) * | 2014-07-10 | 2016-01-14 | Epcos Ag | sensor |
US9697656B2 (en) * | 2014-08-19 | 2017-07-04 | Sensormatic Electronics, LLC | Method and system for access control proximity location |
EP3197916A2 (en) | 2014-09-25 | 2017-08-02 | Amgen Inc. | Protease-activatable bispecific proteins |
US20170303646A1 (en) * | 2014-12-29 | 2017-10-26 | Loop Devices, Inc. | Functional, socially-enabled jewelry and systems for multi-device interaction |
US10373523B1 (en) | 2015-04-29 | 2019-08-06 | State Farm Mutual Automobile Insurance Company | Driver organization and management for driver's education |
US9586591B1 (en) | 2015-05-04 | 2017-03-07 | State Farm Mutual Automobile Insurance Company | Real-time driver observation and progress monitoring |
US10364140B2 (en) * | 2015-09-22 | 2019-07-30 | Nxp Usa, Inc. | Integrating diverse sensors in a single semiconductor device |
DE102015117094B4 (en) * | 2015-10-07 | 2020-04-23 | Tdk Electronics Ag | MEMS rotation rate sensor |
WO2017105472A1 (en) * | 2015-12-17 | 2017-06-22 | Intel Corporation | Microelectronic devices for isolating drive and sense signals of sensing devices |
US10982530B2 (en) * | 2016-04-03 | 2021-04-20 | Schlumberger Technology Corporation | Apparatus, system and method of a magnetically shielded wellbore gyroscope |
CA3030308C (en) * | 2016-07-29 | 2022-04-05 | The Board Of Trustees Of Western Michigan University | Magnetic nanoparticle-based gyroscopic sensor |
US10591645B2 (en) * | 2016-09-19 | 2020-03-17 | Apple Inc. | Electronic devices having scratch-resistant antireflection coatings |
US10996125B2 (en) * | 2017-05-17 | 2021-05-04 | Infineon Technologies Ag | Pressure sensors and method for forming a MEMS pressure sensor |
CN109142785B (en) * | 2018-09-10 | 2021-03-23 | 东南大学 | Horizontal axis sensitive tunnel magnetic resistance accelerometer device based on 3D prints |
CN109737944A (en) * | 2019-03-01 | 2019-05-10 | 成都因赛泰科技有限责任公司 | A kind of MEMS gyroscope with embedded magnetic source |
CN109883456B (en) * | 2019-04-02 | 2024-06-28 | 江苏多维科技有限公司 | Magnetoresistive inertial sensor chip |
CN111521842A (en) * | 2020-06-18 | 2020-08-11 | 中北大学 | Electrostatic rigidity adjustment Z-axis resonant micro-accelerometer based on tunnel magnetic resistance detection |
CN111579818B (en) * | 2020-07-06 | 2021-09-28 | 吉林大学 | High-sensitivity low-noise acceleration detection device and method |
US11844284B2 (en) * | 2021-06-29 | 2023-12-12 | International Business Machines Corporation | On-chip integration of a high-efficiency and a high-retention inverted wide-base double magnetic tunnel junction device |
CN115165005B (en) * | 2022-08-26 | 2024-03-08 | 南京高华科技股份有限公司 | MEMS flow sensor and preparation method thereof |
CN116165576B (en) * | 2022-12-23 | 2023-12-12 | 南方电网数字电网研究院有限公司 | TMRz axis magnetic field sensor |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060156815A1 (en) * | 2003-11-04 | 2006-07-20 | Shyu-Mou Chen | Solid-state gyroscopes and planar three-axis inertial measurement unit |
US20060215442A1 (en) * | 2005-03-24 | 2006-09-28 | Jorg Wunderlich | Conduction control device |
US20070209437A1 (en) * | 2005-10-18 | 2007-09-13 | Seagate Technology Llc | Magnetic MEMS device |
US20090203988A1 (en) * | 2006-02-27 | 2009-08-13 | Nanyang Polytechnic | Apparatus And Method For Non-Invasively Sensing Pulse Rate And Blood Flow Anomalies |
US7673510B2 (en) * | 2004-03-12 | 2010-03-09 | Thomson Licensing | Dual axis vibration rate gyroscope |
Family Cites Families (35)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3800213A (en) * | 1972-10-24 | 1974-03-26 | Develco | Three axis toroidal fluxgate type magnetic sensor |
US5991085A (en) * | 1995-04-21 | 1999-11-23 | I-O Display Systems Llc | Head-mounted personal visual display apparatus with image generator and holder |
JP3000891B2 (en) * | 1995-06-27 | 2000-01-17 | 株式会社村田製作所 | Vibrating gyro |
GB2322196B (en) * | 1997-02-18 | 2000-10-18 | British Aerospace | A vibrating structure gyroscope |
US5911156A (en) * | 1997-02-24 | 1999-06-08 | The Charles Stark Draper Laboratory, Inc. | Split electrode to minimize charge transients, motor amplitude mismatch errors, and sensitivity to vertical translation in tuning fork gyros and other devices |
US6820896B1 (en) * | 1998-05-19 | 2004-11-23 | Peter Norton | Seat occupant weight sensing system |
US6133670A (en) | 1999-06-24 | 2000-10-17 | Sandia Corporation | Compact electrostatic comb actuator |
US6211599B1 (en) | 1999-08-03 | 2001-04-03 | Sandia Corporation | Microelectromechanical ratcheting apparatus |
US7541214B2 (en) * | 1999-12-15 | 2009-06-02 | Chang-Feng Wan | Micro-electro mechanical device made from mono-crystalline silicon and method of manufacture therefore |
US20040102880A1 (en) * | 2001-10-17 | 2004-05-27 | Brown James K | System for monitoring vehicle wheel vibration |
US6944931B2 (en) * | 2002-08-12 | 2005-09-20 | The Boeing Company | Method of producing an integral resonator sensor and case |
US7168318B2 (en) * | 2002-08-12 | 2007-01-30 | California Institute Of Technology | Isolated planar mesogyroscope |
US7040163B2 (en) * | 2002-08-12 | 2006-05-09 | The Boeing Company | Isolated planar gyroscope with internal radial sensing and actuation |
US7071594B1 (en) * | 2002-11-04 | 2006-07-04 | Microvision, Inc. | MEMS scanner with dual magnetic and capacitive drive |
US7054114B2 (en) * | 2002-11-15 | 2006-05-30 | Nve Corporation | Two-axis magnetic field sensor |
DE102004011591A1 (en) * | 2004-03-10 | 2005-09-29 | Robert Bosch Gmbh | connecting element |
US7200032B2 (en) * | 2004-08-20 | 2007-04-03 | Infineon Technologies Ag | MRAM with vertical storage element and field sensor |
US8191756B2 (en) * | 2004-11-04 | 2012-06-05 | Microchips, Inc. | Hermetically sealing using a cold welded tongue and groove structure |
US20070064351A1 (en) * | 2005-09-13 | 2007-03-22 | Wang Shan X | Spin filter junction and method of fabricating the same |
US8397568B2 (en) * | 2006-04-24 | 2013-03-19 | Milli Sensor Systems+Actuators | Bias measurement for MEMS gyroscopes and accelerometers |
AT503995B1 (en) * | 2006-08-07 | 2009-03-15 | Arc Seibersdorf Res Gmbh | MINIATURE SENSOR ACCELERATION |
US7793541B2 (en) * | 2007-06-04 | 2010-09-14 | The Boeing Company | Planar resonator gyroscope central die attachment |
US7987714B2 (en) * | 2007-10-12 | 2011-08-02 | The Boeing Company | Disc resonator gyroscope with improved frequency coincidence and method of manufacture |
EP2203936A2 (en) * | 2007-10-18 | 2010-07-07 | Nxp B.V. | Magnetic detection of back-side layer |
WO2009109969A2 (en) * | 2008-03-03 | 2009-09-11 | Ramot At Tel-Aviv University Ltd. | Micro scale mechanical rate sensors |
US7915891B2 (en) * | 2008-08-14 | 2011-03-29 | The United States Of America As Represented By The Secretary Of The Army | MEMS device with tandem flux concentrators and method of modulating flux |
US9016126B2 (en) * | 2009-01-07 | 2015-04-28 | Honeywell International Inc. | MEMS accelerometer having a flux concentrator between parallel magnets |
US8322028B2 (en) * | 2009-04-01 | 2012-12-04 | The Boeing Company | Method of producing an isolator for a microelectromechanical system (MEMS) die |
US8393212B2 (en) * | 2009-04-01 | 2013-03-12 | The Boeing Company | Environmentally robust disc resonator gyroscope |
ITTO20091042A1 (en) * | 2009-12-24 | 2011-06-25 | St Microelectronics Srl | MICROELETTROMECHANICAL INTEGRATED GYROSCOPE WITH IMPROVED DRIVE STRUCTURE |
JP5558122B2 (en) * | 2010-01-15 | 2014-07-23 | 株式会社リブ技術研究所 | Communication circuit, relay connection circuit, and communication network |
US8453504B1 (en) * | 2010-01-23 | 2013-06-04 | Minyao Mao | Angular rate sensor with suppressed linear acceleration response |
IT1403434B1 (en) * | 2010-12-27 | 2013-10-17 | St Microelectronics Srl | MAGNETIC FIELD SENSOR WITH ANISOTROPIC MAGNETORESISTIVE ELEMENTS, WITH PERFECT ARRANGEMENT OF RELATIVE MAGNETIZATION ELEMENTS |
US9588190B2 (en) * | 2012-07-25 | 2017-03-07 | Silicon Laboratories Inc. | Resonant MEMS lorentz-force magnetometer using force-feedback and frequency-locked coil excitation |
US9429427B2 (en) * | 2012-12-19 | 2016-08-30 | Intel Corporation | Inductive inertial sensor architecture and fabrication in packaging build-up layers |
-
2013
- 2013-07-05 US US13/935,557 patent/US20140026658A1/en not_active Abandoned
- 2013-07-05 US US13/935,558 patent/US20140026659A1/en not_active Abandoned
- 2013-07-06 US US13/936,143 patent/US20140190257A1/en not_active Abandoned
- 2013-07-06 US US13/936,145 patent/US20140026661A1/en not_active Abandoned
- 2013-07-06 US US13/936,144 patent/US20140026660A1/en not_active Abandoned
-
2014
- 2014-02-11 US US14/178,229 patent/US20150226555A1/en not_active Abandoned
- 2014-10-13 US US14/512,469 patent/US20160154070A1/en not_active Abandoned
- 2014-10-20 US US14/518,665 patent/US20150033856A1/en not_active Abandoned
- 2014-10-20 US US14/518,621 patent/US20160154019A1/en not_active Abandoned
- 2014-10-20 US US14/518,355 patent/US20150033854A1/en not_active Abandoned
- 2014-10-20 US US14/518,651 patent/US20150033855A1/en not_active Abandoned
- 2014-10-20 US US14/518,712 patent/US20160154020A1/en not_active Abandoned
- 2014-10-20 US US14/518,607 patent/US20160153780A1/en not_active Abandoned
- 2014-10-20 US US14/518,688 patent/US10012670B2/en not_active Expired - Fee Related
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060156815A1 (en) * | 2003-11-04 | 2006-07-20 | Shyu-Mou Chen | Solid-state gyroscopes and planar three-axis inertial measurement unit |
US7673510B2 (en) * | 2004-03-12 | 2010-03-09 | Thomson Licensing | Dual axis vibration rate gyroscope |
US20060215442A1 (en) * | 2005-03-24 | 2006-09-28 | Jorg Wunderlich | Conduction control device |
US20070209437A1 (en) * | 2005-10-18 | 2007-09-13 | Seagate Technology Llc | Magnetic MEMS device |
US20090203988A1 (en) * | 2006-02-27 | 2009-08-13 | Nanyang Polytechnic | Apparatus And Method For Non-Invasively Sensing Pulse Rate And Blood Flow Anomalies |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20220178692A1 (en) * | 2017-12-21 | 2022-06-09 | Mindmaze Holding Sa | System, method and apparatus of a motion sensing stack with a camera system |
US10802087B2 (en) | 2018-09-11 | 2020-10-13 | Honeywell International Inc. | Spintronic accelerometer |
US10871529B2 (en) | 2018-09-11 | 2020-12-22 | Honeywell International Inc. | Spintronic mechanical shock and vibration sensor device |
US10876839B2 (en) | 2018-09-11 | 2020-12-29 | Honeywell International Inc. | Spintronic gyroscopic sensor device |
CN111413653A (en) * | 2019-01-07 | 2020-07-14 | 中国科学院上海微系统与信息技术研究所 | Magnetic field sensor structure and preparation method thereof |
US11054438B2 (en) | 2019-03-29 | 2021-07-06 | Honeywell International Inc. | Magnetic spin hall effect spintronic accelerometer |
Also Published As
Publication number | Publication date |
---|---|
US20160154070A1 (en) | 2016-06-02 |
US20150034620A1 (en) | 2015-02-05 |
US20140026660A1 (en) | 2014-01-30 |
US20140190257A1 (en) | 2014-07-10 |
US20140026659A1 (en) | 2014-01-30 |
US20160154020A1 (en) | 2016-06-02 |
US20150033855A1 (en) | 2015-02-05 |
US20150226555A1 (en) | 2015-08-13 |
US10012670B2 (en) | 2018-07-03 |
US20160154019A1 (en) | 2016-06-02 |
US20140026658A1 (en) | 2014-01-30 |
US20140026661A1 (en) | 2014-01-30 |
US20150033856A1 (en) | 2015-02-05 |
US20150033854A1 (en) | 2015-02-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US20160153780A1 (en) | Mems gyroscope | |
US9254992B2 (en) | Method of making a MEMS gyroscope having a magnetic source and a magnetic sensing mechanism | |
US20150033853A1 (en) | Mems gyroscope | |
EP2972417B1 (en) | Magnetometer using magnetic materials on accelerometer | |
TWI567393B (en) | Systems and methods for forming, providing and using in-plane, monolithic inertial devices to determine rotation and acceleration | |
US9354283B2 (en) | Sensor and method of controlling the same | |
CN107421525A (en) | A kind of tunnel magnetoresistive disresonance type 3 axis MEMS gyro | |
US20170184687A1 (en) | Sensor | |
CN107356249A (en) | A kind of micro- inertia component of tunnel magnetoresistive detection | |
EP3346281B1 (en) | Mems triaxial magnetic sensor with improved configuration | |
JP2009122041A (en) | Composite sensor | |
CN107449410A (en) | Microthrust test device is detected in electromagnetic drive type tunnel magnetoresistive face | |
US20140290365A1 (en) | Mems device | |
CN111521842A (en) | Electrostatic rigidity adjustment Z-axis resonant micro-accelerometer based on tunnel magnetic resistance detection | |
CN207395750U (en) | Microthrust test device is detected in electromagnetic drive type tunnel magnetoresistive face | |
Marra et al. | 100 nT/√ Hz, 0.5 mm 2 monolithic, multi-loop low-power 3-axis MEMS magnetometer | |
CN207197533U (en) | A kind of tunnel magnetoresistive disresonance type 3 axis MEMS gyro | |
CN110966999A (en) | Monolithic integration triaxial gyro based on tunnel magnetic resistance detection | |
CN207395752U (en) | A kind of micro- inertia component of tunnel magnetoresistive detection | |
Sonmezoglu et al. | Off-resonance operation of a MEMS Lorentz force magnetometer with improved thermal stability of the scale factor | |
US9829318B2 (en) | Gyroscope structure and gyroscope device | |
CN110966997A (en) | Piezoelectric driving type micro gyroscope device for in-plane detection of tunnel magneto-resistive | |
Lee et al. | Design and implementation of a fully-decoupled tuning fork (FDTF) MEMS vibratory gyroscope for robustness improvement | |
CN211696425U (en) | Triaxial microgyroscope device based on tunnel magnetic resistance detection | |
JP2009041949A (en) | Magnetic acceleration sensor |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |