Tdk Corporation

Homare Tokida

Satoshi Abe

Hiraku Hirabayashi

Hiroshi Yamazaki

Takahiro Imai

Yoshiyuki Mizoguchi

Yohei Hirota

Kunihiro Ueda

Shinichirou Mochizuki

Kenkichi Anagawa

Toshiyuki Ayukawa

A magnetic sensor includes at least one sensor main body; a detection circuit provided on the at least one sensor main body, the detection circuit including a magnetic detection element; and a plurality of sensor terminals provided on the at least one sensor main body. The plurality of sensor terminals include a plurality of signal terminals and a plurality of power supply terminals. The plurality of signal terminals are all disposed on a side of one end of the at least one sensor main body. The plurality of power supply terminals include at least one first terminal disposed on the side of the one end of the at least one sensor main body, and a plurality of second terminals disposed on a side of another end of the at least one sensor main body.

Magnetic sensor device

A first, a second, and a third computing circuit respectively generate a first post-computation signal with a second harmonic component reduced as compared with first and second signals, a second post-computation signal with the second harmonic component reduced as compared with third and fourth signals, and a third post-computation signal with the second harmonic component reduced as compared with fifth and sixth signals. A fourth and a fifth computing circuit respectively generate a fourth post-computation signal with a third harmonic component reduced as compared with the first and second post-computation signals, and a fifth post-computation signal with the third harmonic component reduced as compared with the second and third post-computation signals. A sixth computing circuit determines a detected angle value based on the fourth and fifth post-computation signals.

Rotating field sensor

A magnetic sensor includes an MR element and a bias field generation unit. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The bias field generation unit applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.

Magnetic sensor with reduced effect of interlayer coupling magnetic field

A magnetic sensor system includes a scale and a magnetic sensor arranged in a relative positional relationship variable in a first direction, and a computing unit. The magnetic sensor includes a first detection circuit disposed at a first position and a second detection circuit disposed at a second position. Each of the first and second detection circuits includes a spin-valve magnetoresistive element. The difference between the first position and the second position in the first direction is smaller than or equal to 1.25% of a one-pitch amount of change in the relative positional relationship between the scale and the magnetic sensor. The computing unit generates an abnormal-event determination signal indicative of the presence of an abnormal event in the magnetic sensor by computation using detection signals from the first and second detection circuits.

Magnetic sensor system including two detection circuits

A magnetic sensor includes an MR element and a pair of magnets. The MR element includes a magnetization pinned layer having a magnetization pinned in a direction parallel to an X direction, a free layer having a magnetization that varies depending on an X-direction component of an external magnetic field, and a nonmagnetic layer interposed between the magnetization pinned layer and the free layer. The magnetization pinned layer, the nonmagnetic layer and the free layer are stacked to be adjacent in a Y direction. The free layer receives an interlayer coupling magnetic field in a direction parallel to the X direction resulting from the magnetization pinned layer. The pair of magnets applies a bias magnetic field to the free layer. The bias magnetic field includes a first component in a direction opposite to that of the interlayer coupling magnetic field and a second component in a Z direction.

A magnetic sensor system includes a scale and a magnetic sensor arranged in a relative positional relationship variable in a first direction, and a computing unit. The magnetic sensor includes a first detection circuit, a second detection circuit and a third detection circuit that are disposed at a first position, a second position and a third position, respectively. Each of the first to third detection circuits includes a spin-valve MR element. A difference between two of the first to third positions that are the most distant from each other in a first direction falls within a one-pitch amount of change in the relative positional relationship between the scale and the magnetic sensor. The computing unit generates first and second post-computation signals having mutually different phases by computation using detection signals from the first to third detection circuits.

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Tokyo, Japan

Homare Tokida