Alps Green Devices Co., Ltd.

Alps Electric Co., Ltd.

Alps Alpine Co., Ltd.

Alps Green Devices., Ltd.

Masahiro Iizuka

Masamichi Saito

Yosuke Ide

Akira Takahashi

Yoshihiro Nishiyama

Hidekazu Kobayashi

Kenji Ichinohe

Shigenobu Miyajima

Naoki Sakatsume

Tsuyoshi Nojima

Tatsuya Kogure

Tomoo Otsuka

Hiroshi Yamagami

Mitsuo Aratono

Kinya Aoyagi

Hidetoshi Saito

Koichi Mukasa

Ryo Nakabayashi

Takao Mizushima

Akinori Kojima

Tokuo Nakamura

Yutaka Naito

Shinji Mitsuya

Kazuki Iwaya

Kinshiro Takadate

Akira Sato

Seiichi Abiko

Keiichiro Sato

Jinichi Matsuda

Kazuhiro Kaneko

Satoshi Maki

Hideharu Matsuo

Kazuichi Endo

Akihiro Inada

Yasuyuki Kondoh

In a coil-embedded dust core constituting an inductance element, a winding body of a coil disposed inside a coil-embedded dust core and a dust core have a relationship that the inner core volume ratio RV defined below is 3 or more and 5 or less: RV=(V1/V2)/(1−V/Vp), where V1 represents a volume of a region in the dust core located on an inner side of the winding body of the coil when the coil-embedded dust core is viewed in a first direction, which is a direction along a winding axis of the coil, V2 represents a volume of a region in the dust core located on an outer side of the winding body of the coil when the coil-embedded dust core is viewed in the first direction, V represents a volume of the dust core, and Vp represents a volume of the coil-embedded dust core.

Coil-embedded dust core, inductance element, and electric or electronic device

A DC-to-DC converter includes a voltage converter having: a capacitance; at least one inductor configured to store energy and exchange stored energy with the capacitance; and a switching element configured to switch on and off a current flowing through the inductor and change direction of the current at each switching. The inductor includes a variable inductor whose inductance decreases with increase in the current.

DC-to-DC converter

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 current sensor includes a substrate, a conductive body being provided above the substrate and extending in one direction, and magnetoresistance effect elements being provided between the substrate and the conductive body and outputting output signals owing to an induction magnetic field from a current to be measured being conducted through the conductive body, wherein each of the magnetoresistance effect elements has a laminated structure including a ferromagnetic fixed layer whose magnetization direction is fixed, a non-magnetic intermediate layer, and a free magnetic layer whose magnetization direction fluctuates with respect to an external magnetic field, the ferromagnetic fixed layer is a self-pinned type formed by antiferromagnetically coupling a first ferromagnetic film and a second ferromagnetic film through an antiparallel coupling film, the Curie temperatures of the first ferromagnetic film and the second ferromagnetic film are approximately equal, and a difference between the magnetization amounts thereof is substantially zero.

A magnetic balance type current sensor includes a magnetic balance type current sensor including a magnetoresistance effect element whose characteristic changes owing to an induction magnetic field from a current to be measured flowing through a conductor, a feedback coil configured to be disposed in the vicinity of the magnetoresistance effect element and generate a cancelling magnetic field cancelling out the induction magnetic field, a magnetic shield configured to attenuate the induction magnetic field and enhance the cancelling magnetic field, and a hard bias layer configured to be provided on or above the magnetic shield.

Magnetic balance type 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.

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 current sensor includes a magnetic detecting element, a bridge circuit including a plurality of resistance elements, and a feedback coil placed adjacent to the magnetic detecting element and generating a cancelling magnetic field for cancelling the induced magnetic field based on the output from the bridge circuit. The wiring patterns forming the bridge circuit are routed so as not to intersect with each other when seen in a plan view. Only the resistance elements constituting each series circuit of the bridge circuit are connected to each other by the wiring pattern in an enclosed area which encloses each resistance element constituting the bridge circuit, and the wiring pattern branched from the wiring pattern is connected to the terminal which is installed in a quantity of only one, outside the enclosed area.

Current sensor including magnetic detecting element

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.

Magnetoresistive effect elements Rto Rare a TMR element or CPP-GMR element. A multilayer film forming the magnetoresistive effect elements is formed to have a width dimension Tand a length dimension Lperpendicular to the width dimension T. The length dimension Lis longer than the width dimension T. The width dimension of magnetic field generators of the coil is T. The multilayer filmis positioned within the width dimension Tof 60% in total of 30% each to the width dimension Tof the magnetic field generatorsandof the coil in the direction towards both sides from the center of the width dimension Twhen seen in a plan view.

Magnetic coupling-type isolator

An improved magnetic head includes a slider and a thin film element, the later of which is provided on a trailing side of the slider. The slider has core layers. The surfaces of the core layers are abraded so that the thickness of an &agr; phase constituting the, surface structures of the core layers may be reduced to a very small value. In this way, even if a carbon film is directly formed on the core layers, it is still possible to ensure a desired diffusion between the carbon film and the &agr; phase, which effectively prevents the carbon film from separation (peeling) and avoiding the formation of any spot on the carbon film.

Magnetic head producing method

An improved magnetic head comprises a slider and a thin film element, the later of which is provided on a trailing side of the slider. The slider has core layers. The surfaces of the core layers are abraded so that the thickness of an a phase constituting the surface structures of the core layers may be reduced to a very small value. In this way, even if a carbon film is directly formed on the core layers, it is still possible to ensure a desired diffusion between the carbon film and the a phase, thereby effectively preventing the carbon film from separation (peeling) and avoiding the formation of any spot on the carbon film.

Magnetic head having a thin film element

The ZnO amount contained in the ferrite is lowered more than those of conventional ones to increase the mean coefficient of thermal expansion of the ferrite. Thus, a difference between the mean coefficient of thermal expansion of the ferrite and the mean coefficient of thermal expansion of the soft magnetic material is reduced. Further, the Fe.sub.2 O.sub.3 amount contained in the ferrite is suitably controlled to reduce the absolute value of the magnetocrystalline anisotropic energy K1 and the absolute value of the saturation magnetostriction .lambda.S. Thus, the absolute value of the apparent magnetic anisotropic energy is lowered, and the magnetic anisotropy is weakened. The magnetic permeability and the head output can be elevated in a high frequency region by lowering the magnetic anisotropy.

Magnetic head

The magnetocrystalline anisotropic energy Kl is set to not more than 100 J/m.sup.3 and the absolute value of the magnetostriction in the &lt;100&gt; direction, as the magnetic circuit direction, is reduced by appropriately selecting the ferrite material composition. Since the magnetocrystalline anisotropic energy Kl is small, the magnetoelastic energy largely affects the anisotropy of the crystallographic axis. The magnetoelastic energy is made negative and small in magnitude by adjusting the average coefficients of thermal expansion of the ferrite material and glass so as to apply a tensile stress around the magnetic gap of the magnetic head. The &lt;100&gt; direction, i.e., magnetic circuit direction, is thereby allowed to coincide with a hard axis of magnetization. As a result, the permeability of the magnetic head is improved at high-frequency bands.

The present invention relates to a method for measuring three-dimensional spatial magnetic field distributions used particularly in measuring the magnetic field distribution in a small spatial region such as a leakage magnetic field of a magnetic head and the object thereof is a measuring method capable of measuring a high frequency magnetic field in the small spatial region with a high precision.

Growing community of inventors

Niigata-ken, Japan

Masahiro Iizuka