Patents by Inventor Tetsuya Kuwashima
Tetsuya Kuwashima has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8240026Abstract: A method for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.Type: GrantFiled: September 24, 2008Date of Patent: August 14, 2012Assignee: TDK CorporationInventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
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Patent number: 8125743Abstract: A thin-film magnetic head has a magnetoresistive effect read head element. The magnetoresistive effect read head element includes a lower shield layer, an upper shield layer, and a magnetoresistive effect layer formed between the lower shield layer and the upper shield layer. The magnetoresistive effect read head element also includes a lower antiferromagnetic layer. The lower antiferromagnetic layer is contacted with the lower shield layer only at an edge area of the lower shield layer.Type: GrantFiled: June 8, 2007Date of Patent: February 28, 2012Assignee: TDK CorporationInventors: Naoki Ohta, Kosuke Tanaka, Takayasu Kanaya, Kazuki Sato, Yasufumi Uno, Tetsuya Kuwashima
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Patent number: 7978438Abstract: A thin-film magnetic head provided with at least one MR read head element includes a lower shield layer, an upper shield layer, and an MR layer formed between the lower shield layer and the upper shield layer. A profile of the upper shield layer, appeared at an ABS, has obtuse or rounded upper corners at end edges of the upper shield layer along a track-width direction.Type: GrantFiled: July 9, 2007Date of Patent: July 12, 2011Assignee: TDK CorporationInventors: Naoki Ohta, Kosuke Tanaka, Takayasu Kanaya, Kazuki Sato, Yasufumi Uno, Tetsuya Kuwashima
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Patent number: 7933099Abstract: A magnetic head having precisely controlled MR height has a slider substrate and a magnetic head part provided on the slider substrate. The magnetic head part includes, seeing from a medium-opposing surface side, a magnetism detecting element; an upper magnetic shield layer arranged on the magnetism detecting element; an electrode layer separated in a track width direction from the upper magnetic shield layer; and a conductor layer, arranged closer to the slider substrate than are the upper magnetic shield layer and electrode layer, extending in the track width direction so as to be in contact with the upper magnetic shield layer and electrode layer and forming a part of the medium-opposing surface.Type: GrantFiled: April 11, 2007Date of Patent: April 26, 2011Assignee: TDK CorporationInventors: Naoki Ohta, Tetsuya Kuwashima, Kazuki Sato, Kosuke Tanaka
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Patent number: 7916434Abstract: A TMR effect element with sufficiently reduced element resistance and restricted popping noise is provided, which comprises a tunnel barrier layer formed primarily of a metal oxide including many electric charge sites. The electric charge sites density n and the mobility ? of electrons trapped due to the electric charge sites satisfy a relationship expressed by: 0<(ns1?1?ns2?1)?1·(?0??)·(n?)?1<0.2, where ns1 and ns2 are densities of tunnel electrons when an element resistance is a minimum and maximum respectively during reading signals and ?0 is the mobility of electrons when not trapped.Type: GrantFiled: March 24, 2006Date of Patent: March 29, 2011Assignee: TDK CorporationInventors: Shunji Saruki, Kenji Inage, Tetsuya Kuwashima, Hiroshi Kiyono, Katsumichi Tagami, Kazumasa Fukuda, Masahide Kohno
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Patent number: 7911745Abstract: A thin-film magnetic head includes a magneto-resistive effect device of the CPP structure including a multilayer film comprising a stack of a fixed magnetization layer, a nonmagnetic layer and a free layer stacked one upon another in order, with a sense current applied in the stacking direction of the multilayer film, and an upper shield layer and a lower shield layer with the magneto-resistive effect device held between them in the thickness direction, and further comprises a bias magnetic field-applying layer located at each end of the multilayer film in the widthwise direction and a re-magnetizer unit designed such that when the bias magnetic field-applying layers malfunction, they are re-magnetized to go back to normal.Type: GrantFiled: August 24, 2007Date of Patent: March 22, 2011Assignee: TDK CorporationInventors: Yosuke Antoku, Tsuyoshi Umehara, Tetsuya Kuwashima
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Patent number: 7894168Abstract: The invention provides a thin-film magnetic head having a magneto-resistive effect device of the CPP (current perpendicular to plane) structure comprising a multilayer film in which a fixed magnetization layer, a nonmagnetic layer and a free layer are stacked together in order. The fixed magnetization layer, nonmagnetic layer and free layer extend away from an air bearing surface that is a plane in opposition to a medium, the length of the fixed magnetization layer in a depth direction normal to said air bearing surface is greater than the length of the free layer in the depth direction. A shunt layer for shunting the sense current is located at a farther distance in the depth direction than the free layer, and the shunt layer is separated from the free layer by a constant gap in the depth direction.Type: GrantFiled: August 28, 2007Date of Patent: February 22, 2011Assignee: TDK CorporationInventors: Hiroshi Kiyono, Tetsuya Kuwashima
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Patent number: 7784171Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.Type: GrantFiled: May 4, 2007Date of Patent: August 31, 2010Assignee: TDK CorporationInventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
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Patent number: 7743666Abstract: A tunneling effect element, including an insulating layer that forms a tunneling barrier, a lower electrode that is conductive and non-magnetic, and is formed on a bottom surface of said insulating layer, an upper electrode that is conductive and non-magnetic, and is formed on a top surface of said insulating layer, and a transmission member. The transmission member is made of insulating material that is formed surrounding the insulating layer and the lower and upper electrodes. The transmission member is also formed on a surface of an object to be detected, and transmits deformation of the object to be detected to the insulating layer. The tunneling effect element detects a change in stress of the object to be detected as a change in electric resistance.Type: GrantFiled: March 27, 2006Date of Patent: June 29, 2010Assignee: TDK CorporationInventors: Tetsuya Kuwashima, Naoki Ohta
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Patent number: 7672084Abstract: Composite thin-film magnetic head includes a substrate; a first insulation layer on the substrate; an MR read head element on the first insulation layer and provided with a lower shield layer, an upper shield layer and an MR layer with a sense current flowing perpendicular to a surface of the MR layer though the upper and lower shield layers; a second insulation layer on the MR read head element; an inductive write head element on the second insulation layer and provided with a lower magnetic pole layer, a recording gap layer, an upper magnetic pole layer with end portion opposed to an end portion of the lower magnetic pole layer through the recording gap layer and a write coil; and a nonmagnetic conductive layer electrically conducted with the lower shield layer and opposed to the substrate to increase the electrode area between the lower shield layer and the substrate.Type: GrantFiled: April 21, 2009Date of Patent: March 2, 2010Assignee: TDK CorporationInventors: Takeo Kagami, Noriaki Kasahara, Tetsuya Kuwashima
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Patent number: 7672087Abstract: Provided is an MR effect element in which the magnetization of the pinned layer is stably fixed even after going through high temperature process. The MR effect element comprises: a non-magnetic intermediate layer; a pinned layer and a free layer stacked so as to sandwich the non-magnetic intermediate layer; an antiferromagnetic layer stacked to have a surface contact with the pinned layer, for fixing a magnetization of the pinned layer to a direction in-plane of the pinned layer and perpendicular to a track width direction; and hard bias layers provided on both sides in the track width direction of the free layer, for applying a bias field to the free layer, a product ?S×? of a saturation magnetostriction constant ?S of the pinned layer and an internal stress ? on a cross-section perpendicular to a layer surface of the hard bias layer being negative.Type: GrantFiled: March 27, 2007Date of Patent: March 2, 2010Assignee: TDK CorporationInventors: Takayasu Kanaya, Katsuki Kurihara, Tetsuya Kuwashima
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Patent number: 7583462Abstract: Timely and proper flying height adjustment is achieved using a controller, which is designed for a magnetic recording and reproducing apparatus that does not use a magnetic head having a heating element for flying height adjustment without any modification. A head amplifier includes a write amplifier for applying a write current to a write head element, a read amplifier for amplifying a read voltage output from a read head element and outputting a read signal, a heating element driver for applying a heat generating current to at least one heating element for adjusting a flying height, and a heat controller for controlling the heating element driver.Type: GrantFiled: September 6, 2007Date of Patent: September 1, 2009Assignee: TDK CorporationInventors: Naoki Ohta, Tetsuya Kuwashima
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Patent number: 7542245Abstract: Composite thin-film magnetic head includes a substrate; a first insulation layer on the substrate; an MR read head element on the first insulation layer and provided with a lower shield layer, an upper shield layer and an MR layer with a sense current flowing perpendicular to a surface of the MR layer though the upper and lower shield layers; a second insulation layer on the MR read head element; an inductive write head element on the second insulation layer and provided with a lower magnetic pole layer, a recording gap layer, an upper magnetic pole layer with end portion opposed to an end portion of the lower magnetic pole layer through the recording gap layer and a write coil; and a nonmagnetic conductive layer electrically conducted with the lower shield layer and opposed to the substrate to increase the electrode area between the lower shield layer and the substrate.Type: GrantFiled: February 7, 2006Date of Patent: June 2, 2009Assignee: TDK CorporationInventors: Takeo Kagami, Noriaki Kasahara, Tetsuya Kuwashima
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Patent number: 7520165Abstract: Highly efficient and highly sensitive sensors of small size are provided in desired position, desired shape and size for a micro structure that causes elastic deformation at least a part thereof. Moreover, utilizing the sensors allows facilitating to assemble and adjust the components, miniaturizing and simplifying the detection circuit, and measuring a local displacement of a fine part of the micro structure. A micro structure is a cantilever in which a beam part causes elastic deformation. This cantilever includes a sensor detecting elastic deformation of a beam part by tunneling effect.Type: GrantFiled: June 7, 2006Date of Patent: April 21, 2009Assignee: TDK CorporationInventors: Naoki Ohta, Tetsuya Kuwashima
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Publication number: 20090059436Abstract: The invention provides a thin-film magnetic head having a magneto-resistive effect device of the CPP (current perpendicular to plane) structure comprising a multilayer film in which a fixed magnetization layer, a nonmagnetic layer and a free layer are stacked together in order. The fixed magnetization layer, nonmagnetic layer and free layer extend rearward from an air bearing surface that is a plane in opposition to a medium, the length of the depth-wise side of the fixed magnetization layer is longer than that of the free layer, and a shunt layer for shunting a sense current is formed more on the depth-wise side of, and kept constantly away from, the free layer. There are thus much more favorable advantages obtained: even when device size is further reduced and narrowed, degradation of frequency characteristics is hold back, any increase in the thermal magnetic noise is stayed off, and performance fluctuations are minimized.Type: ApplicationFiled: August 28, 2007Publication date: March 5, 2009Applicant: TDK CORPORATIONInventors: Hiroshi Kiyono, Tetsuya Kuwashima
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Publication number: 20090052089Abstract: The thin-film magnetic head of the invention comprises a magneto-resistive effect device of the CPP (current perpendicular to plane) structure including a multilayer film comprising a stack of a fixed magnetization layer, a nonmagnetic layer and a free layer stacked one upon another in order, with a sense current applied in the stacking direction of the multilayer film, and an upper shield layer and a lower shield layer with the magneto-resistive effect device held between them in the thickness direction, and further comprises a bias magnetic field-applying layer located at each end of the multilayer film in the widthwise direction and a re-magnetizer unit designed such that when the bias magnetic field-applying layers malfunction, they are re-magnetized to go back to normal.Type: ApplicationFiled: August 24, 2007Publication date: February 26, 2009Applicant: TDK CORPORATIONInventors: Yosuke Antoku, Tsuyoshi Umehara, Tetsuya Kuwashima
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Publication number: 20090038143Abstract: A method is provided for manufacturing a magneto-resistive device. The magneto-resistive device is for reducing the deterioration in the characteristics of the device due to annealing. The magneto-resistive device has a magneto-resistive layer formed on one surface side of a base, and an insulating layer formed of two layers and deposited around the magneto-resistive layer. The layer of the insulating layer closest to the base is made of a metal or semiconductor oxide. This layer extends over end faces of a plurality of layers made of different materials from one another, which make up the magneto-resistive device, and is in contact with the end faces of the plurality of layers with the same materials.Type: ApplicationFiled: September 24, 2008Publication date: February 12, 2009Applicant: TDK CORPORATIONInventors: Takeo Kagami, Tetsuya Kuwashima, Norio Takahashi
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Publication number: 20080253033Abstract: A magnetic head in which the size of MR height is controlled precisely, a head gimbal assembly and a hard disk drive which are mounted with such a magnetic head, and a method of making a magnetic head in which the size of MR height is controlled precisely. The magnetic head in accordance with the present invention is a magnetic head comprising a slider substrate and a magnetic head part provided on the slider substrate; wherein the magnetic head part comprises, seeing from a medium-opposing surface side, a magnetism detecting element; an upper magnetic shield layer arranged on the magnetism detecting element; an electrode layer separated in a track width direction from the upper magnetic shield layer; and a conductor layer, arranged closer to the slider substrate than are the upper magnetic shield layer and electrode layer, extending in the track width direction so as to be in contact with the upper magnetic shield layer and electrode layer and forming a part of the medium-opposing surface.Type: ApplicationFiled: April 11, 2007Publication date: October 16, 2008Applicant: TDK CORPORATIONInventors: Naoki Ohta, Tetsuya Kuwashima, Kazuki Sato, Kosuke Tanaka
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Patent number: 7436633Abstract: A parasitic capacity C4 generated between a slider substrate and the first shield layer with the first insulating layer as a capacity layer is made substantially equal to a parasitic capacity C2 occurring between a lower magnetic layer and the second shield layer with the third insulating layer as a capacity layer. Preferably, a connection is made between the lower magnetic layer and the slider substrate by a resistance of preferably 100 (?) or lower. Thus, it is possible to provide a thin-film magnetic head that can hold back deterioration in a reproducing device and the occurrence of errors due to crosstalk between a recording device and the reproducing device and extraneous noises.Type: GrantFiled: August 17, 2005Date of Patent: October 14, 2008Assignee: TDK CorporationInventors: Hiroshi Kiyono, Tetsuya Kuwashima, Takeo Kagami, Noriaki Kasahara, Naoki Ohta, Nozomu Hachisuka
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Publication number: 20080239582Abstract: Provided is an MR effect element in which the magnetization of the pinned layer is stably fixed even after going through high temperature process. The MR effect element comprises: a non-magnetic intermediate layer; a pinned layer and a free layer stacked so as to sandwich the non-magnetic intermediate layer; an antiferromagnetic layer stacked to have a surface contact with the pinned layer, for fixing a magnetization of the pinned layer to a direction in-plane of the pinned layer and perpendicular to a track width direction; and hard bias layers provided on both sides in the track width direction of the free layer, for applying a bias field to the free layer, a product ?S×? of a saturation magnetostriction constant ?S of the pinned layer and an internal stress ? on a cross-section perpendicular to a layer surface of the hard bias layer being negative.Type: ApplicationFiled: March 27, 2007Publication date: October 2, 2008Applicant: TDK CORPORATIONInventors: Takayasu Kanaya, Katsuki Kurihara, Tetsuya Kuwashima