Hitachi Metals, Ltd.

Yasunori Abe

Hiroyuki Hoshiya

Makoto Kawakami

Kenichi Meguro

Yasunori Takaki

Yuji Nihei

Kazuhiro Nakamoto

Tomoki Ono

Yasuyuki Okada

Osamu Shimoe

Keizou Katou

Yasuhito Takeuchi

Hideki Inoue

Masaru Noda

Shinji Furuichi

Munetoshi Unuma

Masakatsu Saitoh

Hiromitsu Itabashi

Hitoshi Harata

Hiroyuki Mima

Yukimasa Shonowaki

Masakazu Sugimoto

Fumio Shirasaki

Yasuko Furuichi, Legal Representative

Kenichi Meguroo

Kazuo Suzuki

A magnetic sensor including: a substrate with a main surface; at least two magnetoresistive effect elements formed on the main surface and connected to a power terminal of a bridge circuit; at least two magnetoresistive effect elements formed on the main surface and connected to a ground terminal of the bridge circuit; a first region in which one of the at least two magnetoresistive effect elements connected to the power terminal and one of the at least two magnetoresistive effect elements connected to the ground terminal are disposed; a second region in which another of the at least two magnetoresistive effect elements connected to the power terminal and another of the at least two magnetoresistive effect elements connected to the ground terminal are disposed; and a bias coil including a first bias application part for applying a bias magnetic field to the first region and a second bias application part for applying a bias magnetic field to the second region. Magnetosensitive directions of the two magnetoresistive effect elements connected to the power terminal are the same, magnetosensitive directions of the two magnetoresistive effect elements connected to the ground terminal are the same, and a difference between a cross-sectional area of the first bias application part and a cross-sectional area of the second bias application part is 35.4% or less.

Magnetic sensor, manufacturing method thereof, and current detector using the same

A magnetic sensor includes: a first current line, a second current line and a third current line that are disposed in parallel to each other in sequence in a width direction and electrically connected in series; and a magnetoresistive effect element disposed under the second current line and extending along a direction of extension of the second current line, the magnetoresistive effect element having an electric resistance that changes by an induced magnetic field generated by current flowing through the first current line, the second current line and the third current line, the following inequality expression (1) being satisfied:&#x2264;5&#x2003;&#x2003;(1)where Lis a length from an outside of the first current line to an outside of the third current line in a width direction, and Wis a length in the width direction of the magnetoresistive effect element.

Magnetic sensor

A magnetic sensor device that includes an annular magnetic body, a coil wound around the magnetic body, the coil configured to apply a magnetic field that rotates 360 degrees by a half way point in a peripheral direction of the magnetic body, and a magnetoresistance effect element arranged at a center of the annular magnetic body and including a fixed layer having a magnetization direction fixed in a direction of the magnetic field to be measured. The magnetic body includes a tapered portion located at a position where a line passing through the center of the magnetic body and extending in a shorter-axis direction intersects the magnetic body, the tapered portion having a narrowed portion narrowed down toward the magnetoresistance effect element, and having dumbbell-shaped inner and outer peripheries, and the narrowed portion having a width reduced toward the magnetoresistance effect element.

Magnetic sensor device preventing concentration of magnetic fluxes to a magnetic sensing element

A magnetic sensor device comprises a thin film first magnetic body provided with a magnetic path convergence/divergence section arranged on a predetermined axis, and at least a pair of wing-shaped sections extending from the magnetic path convergence/divergence section toward the opposite sides of the axis, a thin film second magnetic body provided with a magnetic path convergence/divergence section arranged on the predetermined axis to be spaced from the magnetic path convergence/divergence section of the first magnetic body, at least a pair of wing-shaped sections extending from this magnetic path convergence divergence toward the opposite sides of the axis, a first coil wound around the first magnetic body, a second coil wound around the second magnetic body, and a magnetoresistance effect element arranged between the magnetic path convergence/divergence section of the first magnetic body and the of the second magnetic body, wherein the first coil applies a magnetic field to a magnetic path of the first magnetic body, the magnetic path converging/diverging from/to the at least a pair of wing-shaped sections of the first magnetic body to/from the magnetic path convergence/divergence section the second coil applies a magnetic field to a magnetic path of the second magnetic body, the magnetic path diverging/converging from/to the magnetic path convergence/divergence section to/from the at least a pair of wing-shaped sections of the first magnetic body, and a magnetic field is applied to the magnetoresistance effect element along the converged magnetic path.

Magnetic sensor device for suppressing magnetic saturation

The present disclosure provides a magnetic medium, a magnetic encoder, and a method for manufacturing a magnetic medium with high reliability that can obtain the sufficient signal output, while reducing the hysteresis error. The magnetic medium is relatively movable with respect to a magnetic sensor for detecting a magnetic field in a magnetosensitive face.

Magnetic medium for magnetic encoder, magnetic encoder and method for manufacturing magnetic medium

A magnetic sensor includes a plurality of magneto-resistive effect elements each configured by using a magneto-resistive effect film formed by laminating a pinned layer, a nonmagnetic layer, and a free layer in order from a side of a substrate. A first linear pattern is formed in a first portion on the substrate in a first direction. A second linear pattern is formed in a second portion on the substrate in a second direction. A magnetization direction of the first portion is different from a magnetization direction of the second portion. The magneto-resistive effect film is further formed on the substrate. Each of the plurality of magneto-resistive effect elements includes a pair of electrodes formed by the magneto-resistive effect film processed into a predetermined shape.

Method for producing magneto-resistive effect element, magnetic sensor, rotation-angle detection device

A magnetic medium is magnetized in the relative movement direction at a predefined pitch km and a magnetic sensor includes plural magnetoresistive elements whose electrical resistance value changes depending on a magnetic field at a place where the magnetoresistive element is disposed. A position where the magnetoresistive element is disposed is defined as a reference position and, in addition to the magnetoresistive element of this reference position, the magnetoresistive elements as harmonic reducing patterns are disposed at the following positions, with P(n) defined as the n-th prime: a position offset by &#x3bb;m/(2&#xb7;P(n)) from the reference position toward at least one side of the relative movement direction, wherein N&#x2267;n&#x3e;1 and N is a natural number satisfying N&#x3e;3, and a position further offset by &#x3bb;m/(2&#xb7;P(L+1)) from a position offset by &#x3bb;m/(2&#xb7;P(L)), wherein 1&#x3c;L&#x3c;N.

Encoder

Provided are a self-pinned spin valve magnetoresistance effect film, a magnetic sensor using the same, and a rotation angle detection device. The self-pinned spin valve magnetoresistance effect film has a strong coupling magnetic field in a pinned layer, a small reduction in the change in resistance, and superior resistance to magnetic fields without reducing the coercive force in a first ferromagnetic layer, which is a pinned layer in the film, even when exposed to a strong external magnetic field. By inserting a non-magnetic layer between a ground layer and a pinned layer to form the spin valve magnetoresistance effect film, the self-pinned spin valve magnetoresistance effect film having superior resistance to magnetic fields, a magnetic sensor using the same, and a rotation angle detection device are obtained.

Self-pinned spin valve magnetoresistance effect film and magnetic sensor using the same, and rotation angle detection device

To provide a magnetic encoder that is stable relative to an outside force and has only small variation of a gap between a magnetic sensor and a magnetic medium. The magnetic encoder includes a magnetic medium placed on a first member and a magnetic sensor placed on the second member, the first and second member for moving relative to each other. The magnetic sensor includes a sensor substrate, a sensor holding plate for holding the sensor substrate, and a wire for extracting a signal from the magneto-resistive element to outside. The sensor holding plate includes a fixing portion for fixing the sensor holding plate to the second member, a sensor holding member for holding the sensor substrate, and a plurality of arm portions provided in the relative movement direction with the sensor holding member in-between and extending from the fixing portion to constitute a cantilever.

Magnetic encoder

To provide a method which can define the direction and orientation of magnetization of a pinned layer while reducing the number of steps of forming a GMR film. The magnetization direction of the pinned layer is defined in a plurality of directions by forming a plurality of patterns having directivities. Further, when the magneto-resistive effect film is formed, a magnetic field is applied in a direction at an angle set between the angles of the plurality of patterns.

Method for producing magnetoresistive effect element, magnetic sensor, rotation-angle detection device

There is provided an angle sensor and angle detection device of high output and high accuracy with a wide operating temperature range. First through eighth sensor unitsandare produced from spin valve magnetoresistive films that use a self-pinned type ferromagnetic pinned layer comprising two layers of ferromagnetic films that are strongly and anti-ferromagnetically coupled. The respective sensor units are produced via the formation and patterning of thin-films magnetized at angles that differ by 90&#xb0;, and the formation of insulation films. By using, for the ferromagnetic films, CoFe and FeCo films that have similar Curie temperatures to make the difference in magnetization amount be zero, high immunity to external magnetic fields, a broad adaptive temperature range, and high output are realized.

Angle sensor, angle sensor manufacturing method, and angle detection device using the angle sensor

To disclose a magnetic encoder being subjected to only small gap variation between a magnetic sensor element and a magnetic medium and readily assembled, and having a smaller number of components, high sliding resistance, and high stability against outside force, such as shock or the like. The magnetic sensor holding mechanism has a swirling spring plate structure having elasticity with respect to rotation around a rotation axis in a reciprocative slide relative movement direction, elasticity with respect to rotation around a rotation axis in a direction perpendicular to the reciprocative relative movement direction and in parallel to the magnetic medium, and elasticity in the direction perpendicular to the sensor element. A load between 50 mN and 80 mN is applied to press onto the magnetic medium.

Disclosed is a small-sized two-axis magnetic field sensor having a function to cause a magnetic field canceling an external offset magnetic field. The two-axis magnetic field sensor contains a plane coil disposed on a plane and four sets of magneto-resistance element pairs on a plane parallel to the plane coil. The plane coil includes at least two pairs of parallel conductors, and two magneto-resistance elements cross only a single conductor of the coil. A current for canceling the external offset magnetic field is determined in advance, and while a DC current that causes total magnetic fields of biasing magnetic fields plus a magnetic field for canceling the external offset magnetic field flows through the coil, intermediate potential outputs from the magneto-resistance element pairs are detected to measure a magnetic field direction, such as geo-magnetism.

Two-axis geo-magnetic field sensor with elimination of eefect of external offset magnetic fields

A free fall detection device capable of detecting a fall accompanied by rotation is provided. A fall accompanied by rotation is detected based on a waveform of an acceleration signal output from the acceleration detection unit and an angular velocity signal output from the angular velocity detection unit. A gravity center acceleration of the device to be protected is calculated from the acceleration detected by the acceleration detection unit and from the angular velocity detected by the angular velocity detection unit. Even when the device being protected rotates as it falls, the fall of the device can be detected from the detected acceleration or angular velocity. Further, by calculating the gravity center acceleration not affected by the rotation, it is possible to detect a fall of the device with high precision even if the device rotates as it falls.

Free fall detection device

To provide a magnetic encoder having high resolution and a high output, and a magnetoresistive sensor for an encoder. A fine sensor having a reduced demagnetization field is produced by: forming a free layer consists of a laminated soft magnetic film in which two soft magnetic layers are coupled in anti-parallel, and setting the width of a sensor unit to 2 &#x3bc;m to 4 &#x3bc;m.

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Mohka, Japan

Yasunori Abe