Tdk Corporation

Tamon Kasajima

Hiroshi Kobayashi

Taiju Akushichi

Yuichiro Yamaji

Makoto Kameno

Takato Fukui

Osamu Harakawa

Masafumi Kami

To facilitate a change in the number and layout of magnetic field detection devices to be arranged in an array. A magnetic field detection device includes a cancel coil wound around a bobbin, a cover member fixed to the bobbin and covering the cancel coil in a direction perpendicular to the axial direction of the cancel coil, and magnetic sensors fixed to the bobbin or cover member. The cover member has side surfaces and extending in the z-direction and positioned on mutually opposite sides. The side surfaces have first and second engagement portions, respectively, and the first engagement portion has a shape engageable with the shape of the second engagement portion. This makes it possible to arrange a desired number of the magnetic field detection devices.

Magnetic field detection device and magnetic field detection device array

To reduce the number of components and simplify the circuit configuration in a magnetic field detection device capable of detecting a weak magnetic field without using a shield room. A magnetic field detection device includes a cancel coil wound around a winding core part of a bobbin, magnetic sensors fixed to mutually different positions of the bobbin, and a feedback circuit that makes a cancel current flow in the cancel coil according to an output signal from the magnetic sensor to cancel the environmental magnetic field in a cancel space. Since the cancel coil is used in common for the magnetic sensors, it is possible to reduce the number of components to be used and to simplify the circuit configuration.

Disclosed herein is a magnetic sensor that includes a first magnetic field sensor that detects an environmental magnetic field to generate a first magnetic field signal, a second magnetic field sensor that detects a detection target magnetic field to generate a second magnetic field signal, a first filter that removes an AC component in a predetermined frequency band from the first magnetic field signal to extract a DC component, a first compensation coil that applies a first cancelling magnetic field to the second magnetic field sensor based on the DC component, a second compensation coil that applies a second cancelling magnetic field to the second magnetic field sensor based on the second magnetic field signal, and a second filter that removes an AC component in at least a predetermined frequency band from the second magnetic field signal.

Magnetic sensor

To provide a small-sized magnetic sensor capable of achieving closed-loop control. A magnetic sensor includes: a sensor chip mounted on a surface of a substrate such that an element formation surface is perpendicular to the surface of the substrate or inclined by a predetermined angle with respect thereto; an external magnetic member mounted on the surface of the substrate and collecting a magnetic field to be detected in a magnetosensitive element; and a compensating coil wound around the external magnetic member. The compensating coil is thus wound around the external magnetic member, so that it is possible to cancel a magnetic field to be applied to the magnetosensitive element and to prevent the external magnetic member from being magnetically saturated.

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Tokyo, Japan

Tamon Kasajima