Patent application number | Description | Published |
20080239541 | THERMALLY ASSISTED MAGNETIC HEAD, HEAD GIMBAL ASSEMBLY, AND HARD DISK DRIVE - The thermally assisted magnetic head comprises a medium-opposing surface; a magnetic recording device whose distance from a main magnetic pole to a medium is set longer than a distance from the medium-opposing surface to the medium; a first core for receiving light; and a second core positioned between a first light exit surface of the first core and the medium-opposing surface, having a second light exit surface on the medium side; while a distance between positions where an optical intensity distribution center within the first light exit surface and a center of the main magnetic pole are orthographically projected onto a reference plane including the second light exit surface is greater than a distance between an optical intensity distribution center within the second light exit surface and the position where the center of the leading end of the main magnetic pole is orthographically projected onto the reference plane. | 10-02-2008 |
20080239584 | THIN-FILM MAGNETIC HEAD HAVING LAMINATE SHIELDS FOR TOLERATING EXTERNAL MAGNETIC FIELD - Provided is a thin-film magnetic head having an MR element in which the tolerance of external magnetic field is improved even under the condition that shields have smaller areas. The head comprises: an MR element comprising lower and upper shield layers provided so as to sandwich an MR multilayer, one edges of the layers reaching a head end surface on an ABS side; and an electromagnetic transducer comprising main and auxiliary magnetic pole layers, one edges of the layers reaching the head end surface, wherein at least one laminate shield layer for tolerating external magnetic field is provided adjacently on one side or on both sides in a track width direction of at least one layer out of the upper and lower shield layers and the auxiliary magnetic pole layer, and one edge of the at least one laminate shield layer reaching the head end surface. | 10-02-2008 |
20090052076 | THERMALLY ASSISTED MAGNETIC HEAD WITH OPTICAL WAVEGUIDE - While an emitting position of light from an optical waveguide and a magnetic pole end part are made closer to each other, high-density writing onto a magnetic recording medium is realized. | 02-26-2009 |
20090116143 | THIN-FILM MAGNETIC HEAD, HEAD GIMBAL ASSEMBLY, AND HARD DISK SYSTEM - A write shield layer that forms a part of a thin-film magnetic head is set with respect to the widthwise full length W thereof lying substantially on an air bearing surface that is opposite to the recording medium such that when the full length W is trisected, the maximum thickness H | 05-07-2009 |
20090144965 | Method of manufacturing magnetic head and magnetic head substructure - A method of manufacturing a magnetic head includes the steps of: fabricating a magnetic head substructure by forming components of a plurality of magnetic heads on a substrate, the substructure including a plurality of pre-head portions aligned in a plurality of rows; and fabricating a plurality of magnetic heads by separating the plurality of pre-head portions from one another by cutting the substructure. In the step of fabricating the substructure, a plurality of sensors are formed, the sensors respectively showing individual sensor values corresponding to values of a plurality of different parameters each of which has an influence on characteristics of the magnetic head relating to a pole layer and each of which depends on the position of a medium facing surface. In the step of fabricating the magnetic heads, the medium facing surfaces are formed by lapping a surface formed by cutting the substructure so that a composite sensor value that depends on the plurality of individual sensor values shown by the plurality of sensors becomes a predetermined value. | 06-11-2009 |
20090237833 | MAGNETIC TAPE APPARATUS USING PERPENDICULAR MAGNETIC RECORDING - Provided is a magnetic tape apparatus using perpendicular magnetic recording, which has the function corresponding to an soft-magnetic under layer with sufficiently large thickness and enables the magnetic tape to maintain life sufficiently. This magnetic tape apparatus comprises: a tape head comprising at least one write head element for perpendicular magnetic recording; and a soft-magnetic capstan belt having a surface contact with the magnetic tape and pressing the magnetic tape to the tape head at least during recording, for controlling running speed of the magnetic tape by causing the magnetic tape to run together with the soft-magnetic capstan belt. Further it is preferable that at least two capstan-belt axes are further provided, and the soft-magnetic capstan belt is a loop running among the at least two capstan-belt axes. | 09-24-2009 |
20110025309 | ANGLE-OF-ROTATION SENSOR APPARATUS - The angle-of-rotation sensor apparatus of the invention comprises a shaft supported rotatably about an axial center, a permanent magnet fixed to one end face of the shaft, and a magnetic field sensor device located in opposition to the permanent magnet at a constant spacing. The permanent magnet used is in a cuboidal shape and magnetized in the minor axis (X) direction at the rectangular surface opposing to the magnetic field sensor device. The minor axis side is defined as the X direction and the major axis side as the Y direction. Given the opposing surface of the same area, the area where the angle distribution of the magnetic field emitted out of the permanent magnet can be placed in a uniform direction is made so wide that the tolerance range for axial alignment errors between the magnetic field sensor device and the permanent magnet can be enlarged. | 02-03-2011 |
20110025318 | MAGNETIC SENSOR WITH BRIDGE CIRCUIT INCLUDING MAGNETORESISTANCE EFFECT ELEMENTS - A magnetic sensor for detecting a direction of an external magnetic field comprises: a bridge circuit configured to provide an output that changes in accordance with the direction of the external magnetic field, the bridge circuit including four resistance element sections, each of which comprises at least one magnetoresistance effect element; and two resistors connected to respective output terminals of the bridge circuit. The ratio of the resistance of each of the resistors to that of the bridge circuit is at least 2 when the resistance of each of the resistance element sections is at a minimum corresponding to a change in magnetoresistance. | 02-03-2011 |
20110025319 | MAGNETIC SENSOR INCLUDING A BRIDGE CIRCUIT - A magnetic sensor includes a bridge circuit with a first, a second, a third, and a fourth resistor annularly and electrically connected together in this order, and a compensation resistor. The compensation resistor is connected to a first point between the fourth resistor and the first resistor. The first to fourth resistors include a first to fourth tunnel magneto-resistance element, respectively. Each of the magnetization directions in the magnetization fixed layers in the second and fourth magneto resistance elements is opposite to the magnetization direction in the magnetization fixed layer in the first magneto resistance element. The magnetization direction in the magnetization fixed layer in the third magneto resistance element is the same as the magnetization direction in the magnetization fixed layer in the first magneto resistance element. The resistance of the compensation resistor varies with a period of 180 degrees with respect to a rotation angle of the external field. | 02-03-2011 |
20110025320 | MAGNETIC SENSOR - A magnetoresistive element includes magnetoresistive films each having an upper surface and a lower surface, and conductors combining the magnetoresistive films in series and including top electrodes and bottom electrodes. Each one of the top electrodes and corresponding one of the bottom electrodes oppose each other to sandwich corresponding one of the magnetoresistive films. Each electrode of the top electrodes and the bottom electrodes includes a stem section and a branch section, the stem section extending in a direction along a series alignment direction of the magnetoresistive films, and the branch section extending along the lamination plane in a direction intersecting a direction in which the stem section extends. The branch section in the top electrode is in contact with an upper surface of the corresponding magnetoresistive film, and the branch section in the bottom electrode is in contact with a lower surface of the corresponding magnetoresistive film. | 02-03-2011 |
20110025321 | MAGNETIC SENSOR - A magnetic sensor includes first to fourth MR elements. The first and second MR elements are connected at respective ends thereof through a first connecting portion in a central region. The third and fourth MR elements are connected at respective ends thereof through a second connecting portion that crosses the first connecting portion with a distance in a thickness direction in the central region. The first and fourth MR elements are connected at respective other ends thereof through a third connecting portion, and the second and third MR elements are connected at respective other ends thereof through a fourth connecting portion. Resistance values of the first and third MR elements change in a same increasing/decreasing direction, whereas resistance values of the second and fourth MR elements change in an increasing/decreasing direction opposite to the first and third MR elements, depending on an external signal magnetic field. | 02-03-2011 |
20110025322 | MAGNETO-RESISTANCE EFFECT ELEMENT AND SENSOR - A magneto-resistance effect element for a sensor to sense a variation in externally applied magnetism includes a pinned layer having a fixed magnetization direction, a free layer having a magnetization direction which varies in response to an external magnetic field, and an intermediate layer provided between the pinned layer and the free layer. The pinned layer has a planar shape which is long in the fixed magnetization direction and which is short in a direction orthogonal to the fixed magnetization direction. Moreover, the pinned layer preferably has a planar shape in which the pinned layer is divided into a plurality of sections. | 02-03-2011 |
20110031965 | Magnetic Sensor - A magnetic sensor includes a first detection unit and a second detection unit. The first detection unit calculates a first detection angle which is a detected value of a first angle that a direction of an external magnetic field in a first position forms with respect to a first direction. The second detection unit calculates a second detection angle which is a detected value of a second angle that the direction of the external magnetic field in a second position forms with respect to a second direction. The first detection angle includes a first angular error. The second detection angle includes a second angular error. The first angular error and the second angular error differ in phase by an odd number of times ½ of the error period. | 02-10-2011 |
20110221433 | MAGNETIC SENSOR - A magnetic sensor includes a spin valve-type magneto-resistive element, a voltage detection part, a coil, and a current control part, the coil being configured to apply a measuring magnetic field to the spin valve-type magneto-resistive element upon application of a current, the voltage detection part being configured to output a detection signal to the current control part upon detecting an output voltage of the spin valve-type magneto-resistive element reaching a predetermined voltage value, the current control part being configured to control the current to unidirectionally increase or unidirectionally decrease a strength of the measuring magnetic field from an initial value, but upon input of the detection signal, control the current to return the strength of the measuring magnetic field to the initial value, the initial value being a magnetic field strength where the spin valve-type magneto-resistive element reaches saturation magnetization. | 09-15-2011 |
20120038351 | ROTATING FIELD SENSOR - A field generation unit generates a rotating magnetic field including a first partial magnetic field in a first position and a second partial magnetic field in a second position. The first and second partial magnetic fields differ in direction by 180° and rotate in the same direction of rotation. A first detection unit located in the first position has first and second detection circuits whose output signals differ in phase by ¼ the period. A second detection unit located in the second position has third and fourth detection circuits whose output signals differ in phase by ¼ the period. A detected value of the angle that the direction of the rotating magnetic field in a reference position forms with respect to a reference direction is calculated based on a first signal generated from the output signals of the first and third detection circuits and a second signal generated from the output signals of the second and fourth detection circuits. | 02-16-2012 |
20120038359 | ROTATING FIELD SENSOR - A field generation unit generates a rotating magnetic field including a first partial magnetic field in a first position and a second partial magnetic field in a second position. The first and second partial magnetic fields differ in direction by 180° and rotate in the same direction of rotation. A first detection unit detects, in the first position, a first angle that the direction of a first applied field forms with respect to a first direction. The first applied field includes the first partial magnetic field as its main component. A second detection unit detects, in the second position, a second angle that the direction of a second applied field forms with respect to a second direction. The second applied field includes the second partial magnetic field as its main component. A detected value of the angle that the direction of the rotating magnetic field in a reference position forms with respect to a reference direction is calculated based on detected values of the first and second angles. | 02-16-2012 |
20120095712 | ROTATING FIELD SENSOR - An angle detection unit including first to third arithmetic units receives first and second signals that are associated with intensities of components of a rotating magnetic field in mutually different directions. The first arithmetic unit generates a sum of squares signal made up of the sum of squares of the first and second signals. Based on the sum of squares signal, the second arithmetic unit calculates a first error component estimate which is an estimated value of a first error component included in the first signal and a second error component estimate which is an estimated value of a second error component included in the second signal. The third arithmetic unit generates a first corrected signal by subtracting the first error component estimate from the first signal, generates a second corrected signal by subtracting the second error component estimate from the second signal, and calculates a detected angle value based on the first and second corrected signals. | 04-19-2012 |
20120119729 | ROTATING FIELD SENSOR - A rotating field sensor includes a first detection circuit that outputs a first signal indicating the intensity of a component of a rotating magnetic field in a first direction, a second detection circuit that outputs a second signal indicating the intensity of a component of the rotating magnetic field in a second direction, and an arithmetic circuit that calculates a detected angle value based on the first and second signals. Each of the first and second detection circuits includes at least one MR element row. Each MR element row is composed of a plurality of MR elements connected in series. Each MR element has a magnetization pinned layer. The plurality of MR elements forming each MR element row include one or more pairs of MR elements. Magnetization directions of the magnetization pinned layers in two MR elements making up a pair form a predetermined relative angle other than 0° and 180°. | 05-17-2012 |
20120176126 | ROTATION ANGLE SENSOR - A rotation angle sensor includes a magnet that rotates about a rotation axis. The magnet has an end face perpendicular to the rotation axis and has a magnetization in a direction perpendicular to the rotation axis. The rotation angle sensor further includes a magnetic sensor that faces the end face of the magnet and detects a magnetic field produced by the magnet. The magnet includes a plate-shaped portion including the end face, and a ring-shaped portion that is located on a side of the plate-shaped portion farther from the end face and coupled to the plate-shaped portion. The plate-shaped portion does not include any hollow through which the rotation axis passes, whereas the ring-shaped portion includes a hollow through which the rotation axis passes. | 07-12-2012 |
20140021943 | MAGNETIC SENSOR SYSTEM - A magnetic sensor system includes a magnetic field generation unit for generating a target magnetic field and a magnetic sensor for detecting the target magnetic field, and is selectable between an operating state and a non-operating state. The magnetic sensor has a magnetic detection element including a magnetic layer whose magnetization direction varies according to the direction of the target magnetic field in a reference position. When in the operating state, the direction of the target magnetic field in the reference position varies when viewed from the magnetic sensor. When in the non-operating state, the direction of the target magnetic field in the reference position does not vary when viewed from the magnetic sensor and the magnetization direction of the magnetic layer is pinned in a first direction. The magnetic layer has an induced magnetic anisotropy that is imparted in advance to the magnetic layer. | 01-23-2014 |
20140292313 | MAGNETIC SENSOR SYSTEM INCLUDING THREE DETECTION CIRCUITS - A magnetic sensor system includes a scale and a magnetic sensor arranged in a relative positional relationship variable in a first direction, and a computing unit. The magnetic sensor includes a first detection circuit, a second detection circuit and a third detection circuit that are disposed at a first position, a second position and a third position, respectively. Each of the first to third detection circuits includes a spin-valve MR element. A difference between two of the first to third positions that are the most distant from each other in a first direction falls within a one-pitch amount of change in the relative positional relationship between the scale and the magnetic sensor. The computing unit generates first and second post-computation signals having mutually different phases by computation using detection signals from the first to third detection circuits. | 10-02-2014 |
20150066426 | ROTATING FIELD SENSOR - A first, a second, and a third computing circuit respectively generate a first post-computation signal with a second harmonic component reduced as compared with first and second signals, a second post-computation signal with the second harmonic component reduced as compared with third and fourth signals, and a third post-computation signal with the second harmonic component reduced as compared with fifth and sixth signals. A fourth and a fifth computing circuit respectively generate a fourth post-computation signal with a third harmonic component reduced as compared with the first and second post-computation signals, and a fifth post-computation signal with the third harmonic component reduced as compared with the second and third post-computation signals. A sixth computing circuit determines a detected angle value based on the fourth and fifth post-computation signals. | 03-05-2015 |