Tdk Corporation

Makoto Kameno

Osamu Harakawa

Tamon Kasajima

Taiju Akushichi

Takato Fukui

Yuichiro Yamaji

Shuichi Okawa

Koji Kuroki

Chengbin Lin

Kentaro Ushioda

Ikuhito Onodera

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.

To increase, in a magnetic sensor having a magnetoresistive strip and a ferromagnetic film, a magnetic bias to be applied to a magnetoresistive element by magnetically coupling the magnetoresistive strip and ferromagnetic film. A magnetic sensorincludes a magnetoresistive strip S, an insulating filmthat covers the magnetoresistive strip S, and ferromagnetic films Mand Mformed on the insulating filmand arranged in the x-direction through a magnetic gap G extending in the y-direction. The ferromagnetic films Mand Moverlap a plurality of hard magnetic members H through the insulating film. This allows two adjacent hard magnetic members H to be magnetically coupled through the ferromagnetic films Mand M. This makes it possible to increase the magnetic bias to be applied to a magnetoresistive element R without involving an increase in the size of the hard magnetic member H.

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.

An object of the present invention is to provide a magnetic sensor capable of, while suppressing an increase in manufacturing cost, controlling the gap size so as to make the gap between the element formation surface of the sensor chip and the magnetism collecting member as small as possible and to make variations among products fall within a certain range and a manufacturing method for such a magnetic sensor. A magnetic sensor includes a sensor chipmounted on a substratesuch that the element formation surfaceis perpendicular to the substrateand a magnetism collecting membermounted on the substratesuch that the surfacefaces the substrateand the surfacefaces the element formation surface. The surfacesandof the magnetism collecting memberhave flatness higher than that of the other surfaces thereof.

Magnetic sensor and its manufacturing method

An object of the present invention is to enhance detection accuracy of a magnetic sensor having four bridge-connected magnetic sensing elements. A magnetic sensor includes magnetic layers-provided on a surface of the sensor substrateand bridge-connected magnetic sensing elements R-R. The magnetic layerincludes a main area Mand a converging area Shaving a width gradually reduced with increasing distance from the main area M, the magnetic layerincludes a main area Mand converging areas S, Seach having a width gradually reduced with increasing distance from the main area M, and the magnetic layerincludes a main area Mand converging areas S, Seach having a width gradually reduced with increasing distance from the main area M. The end portions of the converging areas S-Sand the end portions of the converging areas S-Sface each other, respectively, through gaps G-G, respectively. The magnetic sensing elements R-Rare disposed on magnetic paths formed by the gaps G-G, respectively. According to the present invention, detection accuracy is enhanced because a magnetic flux generated by current flowing in one magnetic sensing element does not affect the other sensing element.

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Tokyo, Japan

Makoto Kameno