Alps Green Devices Co., Ltd.

Alps Electric Co., Ltd.

Alps Green Devices., Ltd.

Shigenobu Miyajima

Masamichi Saito

Yosuke Ide

Yoshihiro Nishiyama

Akira Takahashi

Kenji Ichinohe

Masahiro Iizuka

Hidekazu Kobayashi

Naoki Sakatsume

Tsuyoshi Nojima

Tatsuya Kogure

Shinji Mitsuya

Mitsuo Aratono

Hideharu Matsuo

Masato Katoh

A current sensor includes a magnetic sensor module including a plurality of magnetic sensor units connected in series. The magnetic sensor units each include a first magnetic sensor element and a second magnetic sensor element which have sensitivity axes oriented in opposite directions. A first terminal of the first magnetic sensor unit is connected to a first potential source. A third terminal of the first magnetic sensor unit is connected to a second potential source. A second terminal and a fourth terminal of the last magnetic sensor unit are connected to constitute a sensor output terminal. The first terminal of each of the magnetic sensor units excluding the first magnetic sensor unit is connected to the second terminal of the next magnetic sensor unit and the third terminal thereof is connected to the fourth terminal of the next magnetic sensor unit.

Current sensor

A magnetic balance type current sensor includes a magnetoresistance effect element whose resistance value changes owing to the application of an induction magnetic field from a current to be measured; a feedback coil disposed in the vicinity of the magnetoresistance effect element and generating a cancelling magnetic field cancelling out the induction magnetic field; a magnetic field detection bridge circuit including two outputs causing a voltage difference corresponding to the induction magnetic field to occur; and a magnetic shield attenuating the induction magnetic field and enhancing the cancelling magnetic field, wherein, on the basis of the current flowing through the feedback coil at the time of an equilibrium state in which the induction magnetic field and the cancelling magnetic field are cancelled out, the current to be measured is measured, wherein the feedback coil, the magnetic shield, and the magnetic field detection bridge circuit are formed on a same substrate.

Magnetic balance type current sensor

A magnetic-balance-system current sensor includes: a magnetoresistive element, a resistance value of the magnetoresistive element being changed by applying an induction magnetic field generated by a measurement target current; magnetic cores disposed near the magnetoresistive element; a feedback coil disposed near the magnetoresistive element and configured to generate a cancelling magnetic field that cancels out the induction magnetic field; and a magnetic-field detecting bridge circuit having two outputs. The measurement target current is measured on the basis of a current flowing through the feedback coil when the induction magnetic field and the induction magnetic field and the cancelling magnetic field cancel each other out. The feedback coil, the magnetic cores, and the magnetic-field detecting bridge circuit are formed on a same substrate. The feedback coil is of a spiral type, and the magnetic cores are provided above and below the feedback coil.

Magnetic-balance-system current sensor

A magnetic balance type current sensor measures a measured current which flows in a feedback coil when electrical conduction is provided by a voltage difference according to an induction magnetic field from the measured current and an equilibrium state is reached in which the induction magnetic field and a cancel magnetic field cancel each other. Sensor elements in a pair are arranged at positions with magnetic field from the measured current. The magnetization direction of the pinned magnetic layer in the magnetoresistive effect element of one sensor element is aligned in a forward direction with respect to the magnetic field formed by the measured current. The magnetization direction of the pinned magnetic layer in the magnetoresistive effect element of the other sensor element is aligned in a reverse direction with respect to the magnetic field formed by the measured current.

In a thin-film magnetic head manufacturing method and apparatus, lapping is continued until the MR height of a magnetoresistive sensor falls into a finish tolerance range and the lapping time from the beginning of lapping exceeds a predetermined time, thereby substantially reducing the recession between an ABS of a slider bar and a surface of a thin-film magnetic element opposing a recording medium.

Thin-film magnetic head manufacturing method and apparatus

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Niigata-ken, Japan

Shigenobu Miyajima