Apple Inc.

Western Digital (fremont), Inc.

Hitachi Global Storage Technologies Netherlands B.v.

International Business Machines Corporation

Hitachi Global Storage Technologies B.v.

Savas Gider

Jian Guo

Daniele Mauri

Vladimir Nikitin

John Greer Elias

Ming Mao

Wen-Chien David Hsiao

Chaitanya Mudivarthi

Hui Zhao

Kuok San Ho

Joyce Marie Mullenix

Roberto M Ribeiro

Guangwu Duan

Majid Khan

Tongbi T Jiang

Hardayal Singh Gill

Edward Hin Pong Lee

Manoj K Bhattacharyya

Brad G Boozer

Sining Mao

Changqing Shi

Chih-Ching Hu

Steven C Rudy

Guanxiong Li

Quan-chiu Harry Lam

James G Horiuchi

Jiahui Liang

Anup Roy

Terence Tin-Lok Lam

Patrick E O'Brien

Yansheng Luo

Gregory B Arndt

David MacNeil

William Scott Lee

Xiaoyu Sui

Ashwin Balasubramanian

Neil David Knutson

Caleb C Han

Wenchein Hsiao

Hong Pan

Roham Solasi

Jason Janesky

Goncalo Albuquerque

A hybrid Hall/MR magnetometer with self-calibration includes a circuit coupled to a magnetometer and configured to determine whether the magnetometer is to operate in a sensing operation mode or a self-calibration operation mode. The magnetometer comprises a Hall sensor and MR sensor coupled to the circuit. In accordance with determining a sensing operation mode, the Hall sensor is turned off and the MR sensor is turned on; and an external magnetic field is measured using the MR sensor. The magnetic field measurement is calibrated using a MR sensor bias error determined in a self-calibration operation mode of the sensor.

Hybrid Hall-effect/Magnetoresistance (MR) magnetometer with self-calibration

Embodiments are disclosed for yoke structures for improved magnetometer performance. In an embodiment, a magnetometer comprises: a yoke structure comprising at least one hard magnetic layer and at least one soft magnetic layer arranged along a dimension of the yoke structure, where a first coercivity of the at least one hard magnetic layer is greater than a second coercivity of the at least one soft magnetic layer; and at least one magnetic sensing element located in proximity to the at least one soft magnetic layer. In another embodiment, a magnetometer comprises: a multilayer yoke structure comprising layers of non-magnetic material and magnetic material along a dimension of the yoke structure; and at least one magnetic sensing element located in proximity to the yoke structure.

Yoke structures for magnetometers

Disclosed is a compact, multi-user magnetic tracking system. In an embodiment, a compactness is achieved by using a single coil and inertial sensors at the transmitter and magnetometers and inertial sensors at the receiver for sensing the magnetic field generated by the single coil and for determining a position and attitude of the receiver relative to the transmitter. The transmitter and receiver each include a wireless transceiver for exchanging clock synchronization data and sending transmitter attitude data to the receiver. In another embodiment, frequency or time division multiplexing is used to differentiate between multiple users of the multi-user magnetic tracking system.

Compact, multi-user, multi-level, multi-target magnetic tracking system

Aspects of the subject disclosure include a pressure-sensing device consisting of a housing including a membrane and one or more piezoresistive elements disposed on the membrane to sense a displacement due to a deflection of the membrane. A first set of electrodes is disposed over the membrane, and a second set of electrodes is disposed on a permeable port of the device at a distance from the membrane. The first and second sets of electrodes form an electrostatic actuator to exert a repulsive force onto the membrane to reduce the deflection of the membrane.

Multifunction magnetic and piezoresistive MEMS pressure sensor

Disclosed is a magnetometer architecture that couples one or more coils to a magnetic yoke to allow the reset of the magnetic yoke and one or more magnetic field sensors simultaneously after, for example, exposure to a large stray magnetic field. Also, disclosed is a magnetometer architecture that integrates separate magnetic pole pieces offset from the yoke that are each wound by a reset coil to allow reset of the one or more magnetic field sensors.

Magnetometer with integrated reset coils

Systems, methods, apparatuses and non-transitory, computer-readable mediums are disclosed for short-range position tracking using a stationary magnetic field gradient. In an embodiment, a method comprises: obtaining, by a sensing array of a device worn or held by a user in an environment, a measurement of a stationary magnetic field generated by a magnetic source in the environment, the stationary magnetic field being independent of an ambient magnetic field in the environment; determining based on the measurement, a change in the magnetic field over time; determining based on the measurement, a change in the magnetic field over distance; obtaining, by the processor, a rotation angle of the device; determining a velocity of the device based on the change in the magnetic field over time, the change in the magnetic field over distance and the rotation angle of the device; and integrating the velocity to obtain a position of the device.

Short-range position tracking using stationary magnetic field gradient

Aspects of the subject technology relate to an apparatus including a housing, one or more piezoresistive elements and a magnetic actuator. The housing includes a membrane, and the piezoresistive elements are disposed on the membrane to sense a displacement due to a deflection of the membrane. The magnetic actuator is disposed inside a cavity of the housing. The magnetic actuator exerts a repulsive force onto the membrane to reduce the deflection of the membrane.

Disclosed is a compact 3-axis coil design for a magnetic tracking system. In an embodiment, compactness is achieved by using a 3-axis coil in the transmitter that includes a scaffold design with a side surface having a curved groove for guiding one or more windings of a z-axis coil, such that the physical geometry is not increased.

Compact 3-axis coil design for magnetic tracking

An electronic device can include a housing defining an internal volume and a pressure sensor assembly disposed in the internal volume and in communication with an ambient environment. The pressure sensor assembly can include a structure at least partially enclosing a sensor volume, a pressure sensor affixed to a die disposed in the sensor volume, and an exposed moisture detection conductor positioned in the sensor volume.

Exposed wire-bonding for sensing liquid and water in electronic devices

Magnetic sensing technology can be used to detect changes, or disturbances (e.g., changes in magnetic field strength), in magnetic fields and can be used to measure the precise location/positioning of an electronic device in proximity to a magnetic source. In order to avoid interference by earth's static magnetic field, a modulated magnetic field can be used for magnetic based proximity sensing. Received modulated magnetic field signals can be demodulated to determine a received magnetic field strength. A drive current of a magnetic transmitter coil can be varied to maintain the detected magnetic field strength at a target value or within a desirable range. The drive current can also be varied to remain below a burnout current level that can cause damage to the transmitter coil.

Dynamic current control of a transmitter for magnetic proximity sensing

Magnetic sensing technology can be used to detect changes, or disturbances (e.g., changes in magnetic field strength), in magnetic fields and can be used to measure the precise location/positioning of an electronic device in proximity to a magnetic source. In order to avoid interference by earth's static magnetic field, a modulated magnetic field can be used for magnetic based proximity sensing. Received modulated magnetic field signals can be demodulated to determine proximity of the sensor to the source of the modulated magnetic field. Devices such as gloves or devices with fingertip nodes based on receiving modulated magnetic fields can be used to detect user hand position.

Magnetic sensor based proximity sensing

Disclosed is a magnetometer architecture that uses a separate shield to minimize cross-axis sensitivity with low impact on main axis sensitivity. In an embodiment, a magnetometer with cross-axis shielding comprises: a ring shield; a magnetic yoke disposed within the ring shield; and one or more magnetic field sensors disposed between the ring shield and the magnetic yoke, the magnetic field sensors positioned relative to the ring shield and the magnetic yoke such that flux induced by a magnetic field is absorbed in a cross-axis direction of the magnetometer.

Cross-axis shield for out-of-plane magnetometer

A magnetic read apparatus has an air-bearing surface (ABS) and includes a read sensor and a rear magnetic bias structure. The read sensor includes first and second free layers, a spacer layer and a rear surface opposite to the ABS. The spacer layer is nonmagnetic and between the first and second free layers. The read sensor has a track width in a cross track direction parallel to the ABS. The rear magnetic bias structure magnetically biases the read sensor a stripe height direction perpendicular to the ABS. The read sensor is between the ABS and the rear magnetic bias structure. The rear magnetic bias structure has a width in the cross track direction and a length in the stripe height direction. The length is greater than the width. The width of the rear magnetic bias structure is substantially equal to the track width of the read sensor.

Dual free layer magnetic reader having a rear bias structure having a high aspect ratio

A method provides a magnetic read apparatus. A sensor stack is deposited. The read sensor is defined from the stack such that the sensor has sides forming a junction angle of 75 degrees-105 degrees from a sensor bottom. Defining the sensor includes performing a first ion mill at a first angle and a first energy and performing a second ion mill at a second angle greater than the first angle and at a second energy less than the first energy. The first angle is 5 degrees-30 degrees from normal to the top surface. After the first ion mill, less than half of the stack's bottom layer depth remains unmilled. Magnetic bias structure(s) adjacent to the sides may be formed. The magnetic bias structure(s) include a side shielding material having at least one of the saturation magnetization greater than 800 emu/cmand an exchange length less than five nanometers.

Method and system for fabricating high junction angle read sensors

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San Jose, CA, United States of America

Savas Gider