US 12,228,623 B2
Magnetic sensor, magnetic encoder, lens position detection device, distance measuring device, and manufacturing method for magnetic sensor
Tsuyoshi Umehara, Tokyo (JP); Kentaro Harada, Tokyo (JP); and Yongfu Cai, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Feb. 22, 2023, as Appl. No. 18/172,796.
Claims priority of application No. 2022-031193 (JP), filed on Mar. 1, 2022.
Prior Publication US 2023/0280419 A1, Sep. 7, 2023
Int. Cl. G01R 33/09 (2006.01); G01B 7/00 (2006.01); G01D 5/12 (2006.01)
CPC G01R 33/093 (2013.01) [G01B 7/003 (2013.01); G01D 5/12 (2013.01); G01R 33/091 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A magnetic sensor configured to detect a target magnetic field including a magnetic field component in a first direction, the magnetic sensor comprising:
a first resistor, a second resistor, a third resistor, and a fourth resistor each configured to change in resistance with change in strength of the magnetic field component;
a power supply port;
a ground port; and
a first output port, wherein
the first resistor and the second resistor are provided in this order from the power supply port side in a first path that connects the power supply port and the first output port,
the third resistor and the fourth resistor are provided in this order from the ground port side in a second path that connects the ground port and the first output port,
a distance between a first position in the first resistor and a second position in the second resistor in the first direction is equal to an odd number of times ½ of a predetermined pitch,
a distance between a third position in the third resistor and a fourth position in the fourth resistor in the first direction is equal to an odd number of times ½ of the predetermined pitch,
a distance between the first position and the third position in the first direction is equal to zero or an integral number of times of the predetermined pitch,
the predetermined pitch is a length corresponding to one period of a change in the strength of the magnetic field component, wherein the strength of the magnetic field component periodically changes with a predetermined period along the first direction,
the magnetic sensor further includes a plurality of magnetoresistive elements,
each of the plurality of magnetoresistive elements includes a magnetization pinned layer, a free layer, and a gap layer located between the magnetization pinned layer and the free layer,
the magnetization pinned layer has a first magnetization whose direction is fixed,
the free layer has a second magnetization whose direction is variable within a plane parallel to both of the first direction and a second direction orthogonal to the first direction,
the magnetization pinned layer, the free layer, and the gap layer are stacked in a third direction orthogonal to the first direction and the second direction,
the first to fourth resistors are formed of the plurality of magnetoresistive elements,
the first magnetization of the magnetization pinned layer in the first and fourth resistors contains a component in a first magnetization direction being one direction parallel to the first direction, and
the first magnetization of the magnetization pinned layer in the second and third resistors contains a component in a second magnetization direction opposite to the first magnetization direction.