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公开(公告)号:US11199425B2
公开(公告)日:2021-12-14
申请号:US16584840
申请日:2019-09-26
Applicant: Apple Inc.
Inventor: Savas Gider , Jian Guo , John Greer Elias
Abstract: 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.
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公开(公告)号:US20190369169A1
公开(公告)日:2019-12-05
申请号:US15993528
申请日:2018-05-30
Applicant: Apple Inc.
Inventor: Savas Gider , Jian Guo , Chaitanya Mudivarthi
Abstract: 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.
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公开(公告)号:US10295612B2
公开(公告)日:2019-05-21
申请号:US15332119
申请日:2016-10-24
Applicant: Apple Inc.
Inventor: Jian Guo
Abstract: An array of resistive sensor circuits may be used to gather sensor data. Each resistive sensor circuit may have a resistive sensor and an associated switch. Row decoder circuitry may supply rows of the sensor circuits with control signals on row lines. Capacitors associated with respective columns of the array may be provided with an initialization voltage. The control signals on the row lines may be used to turn on the switches in a selected row of the resistive sensor circuits and thereby discharge the capacitors through the resistive sensors of that row. Comparators may have first inputs coupled to the capacitors and second inputs that receive a reference voltage. A column readout circuit may have memory and processing circuitry that receives count values from a counter and that stores the count values in response to toggling output signals from the comparators.
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公开(公告)号:US10094888B2
公开(公告)日:2018-10-09
申请号:US14947968
申请日:2015-11-20
Applicant: APPLE INC.
Inventor: Henry H. Yang , Jian Guo
IPC: G01R33/00 , G01R33/022 , G01R33/028
Abstract: Systems, methods, and computer-readable media for calibrating the offset of a magnetometer assembly with reduced power are provided. In one embodiment, a method for operating an assembly may include determining a difference between a current signal measurement output component of a first magnetometer sensor and a previous signal measurement output component of the first magnetometer sensor, comparing the determined difference with a current threshold value, and generating an assembly output based on the comparing, where, when the determined difference is greater than the current threshold value, the generating may include providing a first assembly output using a current offset output component of a second magnetometer sensor, and, when the determined difference is less than the current threshold value, the generating may include providing a second assembly output using a previous offset output component of the second magnetometer sensor.
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公开(公告)号:US20170090003A1
公开(公告)日:2017-03-30
申请号:US15236137
申请日:2016-08-12
Applicant: Apple Inc.
Inventor: Jian Guo
IPC: G01R35/00
CPC classification number: G01R35/00 , G01R33/0017 , G01R33/0206 , G01R35/005
Abstract: Systems, methods, and computer-readable media for efficiently testing sensor assemblies are provided. A test station may be operative to test a three-axis magnetometer sensor assembly by holding the assembly at each one of three test orientations with respect to an electromagnet axis. At each particular test orientation for each particular sensor axis, a difference may be determined between any magnetic field sensed by that sensor axis during the application of a first magnetic field along the electromagnet axis and any magnetic field sensed by that sensor axis during the application of a second magnetic field along the electromagnet axis. Those determined differences may be leveraged with the magnitudes of the first and second magnetic fields and the vector component of the electromagnet axis on each one of the sensor axes at each one of the test orientations to determine the sensitivity performances for each one of the sensor axes.
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公开(公告)号:US11860246B1
公开(公告)日:2024-01-02
申请号:US16782012
申请日:2020-02-04
Applicant: Apple Inc.
Inventor: Hong Pan , Jian Guo , John G. Elias , Savas Gider
IPC: G06F3/01 , G01R33/028 , G06F3/0346 , G01C19/56 , G02B27/01 , G01R33/00
CPC classification number: G01R33/028 , G01C19/56 , G01R33/0094 , G02B27/0101 , G06F3/012 , G06F3/0346 , G02B2027/0138
Abstract: 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.
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公开(公告)号:US20220090942A1
公开(公告)日:2022-03-24
申请号:US17483122
申请日:2021-09-23
Applicant: Apple Inc.
Inventor: Guangwu Duan , Jian Guo , John Greer Elias , Savas Gider
Abstract: 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.
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公开(公告)号:US20220065958A1
公开(公告)日:2022-03-03
申请号:US17410980
申请日:2021-08-24
Applicant: Apple Inc.
Inventor: Guangwu Duan , Jian Guo , John Greer Elias , Savas Gider
IPC: G01R33/36 , G01R33/385 , G01R33/34
Abstract: 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.
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公开(公告)号:US10353019B2
公开(公告)日:2019-07-16
申请号:US15213314
申请日:2016-07-18
Applicant: Apple Inc.
Inventor: Jian Guo
Abstract: A high dynamic range magnetometer architecture and method are disclosed. In an embodiment, a magnetometer sensor comprises: a variable magnetic gain stage including a plurality of selectable signal gain paths, each signal gain path including a magnetic sensor and a magnetic flux concentrator, and for each signal gain path the magnetic flux concentrator being positioned a different distance from the magnetic flux concentrator to provide a different magnetic gain for the signal gain path; a variable magnetic sensing stage coupled to the variable magnetic gain stage, the variable magnetic sensing stage operable to provide variable magnetic sensing to each signal gain path; and a gain control stage coupled to the variable magnetic sensing stage, the gain control stage operable to select one of the signal gain paths and to provide signal conditioning to the selected signal gain path.
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公开(公告)号:US20190086480A1
公开(公告)日:2019-03-21
申请号:US15711787
申请日:2017-09-21
Applicant: Apple Inc.
Inventor: Jian Guo
Abstract: Systems, methods, apparatuses and non-transitory computer-readable mediums are disclosed for a self-calibrating system architecture for magnetic distortion compensation. In an embodiment, an electronic system comprises: a magnetometer; a plurality of spaced-apart calibration coils proximate to the magnetometer; first circuitry configured to excite the calibration coils during a calibration phase of the electronic system; second circuitry configured to measure a first magnetic field vector in a vicinity of the magnetometer that is generated by the excited calibration coils; third circuitry configured to: generate sensitivity values based on the first magnetic field vector measurement and a baseline magnetic field vector; and a storage device configured for storing the sensitivity values.
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