Patents by Inventor Toshinori Watanabe

Toshinori Watanabe 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).

  • Publication number: 20020167759
    Abstract: A thin-film magnetic head of the present invention having a small gap depth has a lower magnetic pole section including a front portion close to a face of the head opposing a recording medium, the front portion having two side faces flush with two side faces of an upper magnetic core layer formed above the lower magnetic pole section. The lower magnetic pole section does not protrude from the two sides of the upper magnetic pole layer. According to this structure, side writing can be suitably prevented while decreasing the gap depth, and a thin-magnetic head having superior write characteristics can be provided.
    Type: Application
    Filed: April 29, 2002
    Publication date: November 14, 2002
    Applicant: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Toshinori Watanabe
  • Patent number: 6466403
    Abstract: The present invention provides a thin film magnetic head having a recording track width of 1 &mgr;m or less, and a method for manufacturing the thin film magnetic head having a recording track width of 1 &mgr;m or less. In the thin film magnetic head, an upper core layer and a lower core layer extend from a back region toward a magnetic pole tip region, and are exposed at a medium opposing surface, and a gap layer is provided, in the magnetic pole tip region, between the upper core layer and the lower core layer. An insulation layer is deposited on the lower core layer, and a groove that extends from the medium opposing surface toward the back region is provided in the magnetic pole tip region of the insulation layer. A lower magnetic pole layer, the gap layer, and an upper magnetic pole layer are deposited in the groove. The lower magnetic pole layer is joined to the lower core layer, while the upper magnetic pole layer is joined to the upper core layer.
    Type: Grant
    Filed: March 22, 2000
    Date of Patent: October 15, 2002
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Toshihiro Kuriyama, Toshinori Watanabe
  • Publication number: 20020080524
    Abstract: A main magnetic pole layer is formed on an insulating layer flattened into a high-flatness surface, and a yoke layer having a large film thickness is formed on the main magnetic pole layer independently of the main magnetic pole. The main magnetic pole layer has a front end surface formed in a shape with a width size gradually increasing in a direction of track width as the front end surface departs farther away from an auxiliary magnetic pole layer. A perpendicular magnetic recording head can be provided which can suppress the occurrence of fringing in a recording pattern, and can form the main magnetic pole layer with high pattern accuracy, and can satisfactorily introduce a recording magnetic field to a fore end of the main magnetic pole layer.
    Type: Application
    Filed: December 18, 2001
    Publication date: June 27, 2002
    Applicant: Alps Electric Co., Ltd.
    Inventors: Toru Takahashi, Hisayuki Yazawa, Hideki Gochou, Kiyoshi Kobayashi, Minoru Yamada, Kiyoshi Sato, Toshinori Watanabe
  • Publication number: 20020080523
    Abstract: A perpendicular magnetic recording head includes an auxiliary magnetic pole layer exposed at a surface facing a recording medium, a main magnetic pole layer deposited on the auxiliary magnetic pole layer with an insulating layer therebetween, a coil layer for applying a recording magnetic field to the auxiliary magnetic pole layer and the main magnetic pole layer, and a connecting layer placed on the auxiliary magnetic pole layer toward the back from the surface facing the recording medium. At the surface facing the recording medium, the upper base of the main magnetic pole layer is wider than the lower base so that the width in the track width direction of the main magnetic pole layer gradually increases with distance from the auxiliary magnetic pole layer. A method for making such a perpendicular magnetic recording head is also disclosed.
    Type: Application
    Filed: December 18, 2001
    Publication date: June 27, 2002
    Applicant: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Toshinori Watanabe, Hideki Gochou, Hisayuki Yazawa, Kiyoshi Kobayashi, Akira Koyama
  • Publication number: 20020071209
    Abstract: A thin-film magnetic head includes a lower core layer, a gap layer, an upper pole layer, and an upper core layer. At the joint between the upper pole layer and the upper core layer, the width of the upper core layer is larger than the width of the upper pole layer, and also the inner end of the upper core layer is located at the back of the inner end of the upper pole layer. Alternatively, a thin-film magnetic head includes a lower core layer, a recording core, an upper core layer, a coil, and a magnetic intermediate layer. The magnetic intermediate layer has a higher saturation flux density than that of the upper core layer. Methods for fabricating thin-film magnetic heads are also disclosed.
    Type: Application
    Filed: March 30, 2001
    Publication date: June 13, 2002
    Inventors: Toshinori Watanabe, Kiyoshi Sato, Kiyoshi Kobayashi, Masaki Ikegami, Hiromi Ikegami, Chiaki Ikegami
  • Patent number: 6352621
    Abstract: PtMn films are used as antiferromagnetic layers of a dual spin-valve type magnetoresistive sensor. An exchange anisotropic magnetic field is achieved regardless of whether the PtMn film is formed over or under the pinned magnetic layer. Also, an effective exchange anisotropic magnetic field is produced even with heat treatment at a relatively low temperature. Alternatively, a PtMn film is used as an antiferromagnetic layer of a spin-valve film laminate. The use of a PtMn film enables a sufficient exchange anisotropic magnetic field to be produced even with a relatively low heat treatment temperature and a relatively small film thickness. Therefore, the number of total layers of the spin-valve film laminate can be increased to increase a magnetoresistance ratio, and a total thickness of the spin-valve film laminate can be made relatively small.
    Type: Grant
    Filed: August 17, 2000
    Date of Patent: March 5, 2002
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe
  • Publication number: 20020018317
    Abstract: In a thin film magnetic head, a face surface faces a recording medium and a front surface of an upper core layer is a curved surface which gradually retreats in a height direction generally perpendicular to the face surface as it approaches both sides thereof, and the thickness of the upper core layer gradually increases in the height direction. It is thus possible to appropriately suppress the occurrence of side fringing, efficiently cause a magnetic flux to flow from the upper core layer to an upper pole layer, and make the thin film magnetic head adaptable to a higher recording density.
    Type: Application
    Filed: March 8, 2001
    Publication date: February 14, 2002
    Inventors: Kiyoshi Sato, Toshinori Watanabe, Hideki Gochou, Kiyoshi Kobayashi, Toru Takahashi, Hisayuki Yazawa, Hiromi Ikegami, Chiaki Ikegami
  • Patent number: 6346338
    Abstract: A thin film magnetic head includes an upper core layer and a lower core layer which are made of an Fe—M—O alloy, an Fe—M—T—O alloy or an NI—Fe—X alloy so that the upper core layer has a high saturation magnetic flux density, low coercive force and high resistivity, and the lower core layer has a lower saturation magnetic flux density than the upper core layer, low coercive force, high resistivity, and a low magnetostriction constant. Also the lower core layer is formed so that the thickness gradually decreases toward both side ends, and a gap layer can be formed on the lower core layer to have a uniform thickness. Since the lower core layer is formed by sputtering, a material having excellent soft magnetic material can be used, thereby enabling recording at high frequency.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: February 12, 2002
    Assignee: Alps Electric Co., Ltd.
    Inventors: Toshinori Watanabe, Akira Takahashi, Fumihito Koike, Nobuhiro Hayashi, Yoshihiro Kanada, Kiyoshi Kobayashi, Kiyoshi Sato, Eiji Umetsu, Takashi Hatanai, Akihiro Makino
  • Publication number: 20020006013
    Abstract: A thin-film magnetic head for perpendicular magnetic recording comprising an auxiliary magnetic pole layer; a main magnetic pole layer; a conductive coil layer in a spiral shape which is disposed between the main magnetic pole layer and the auxiliary magnetic pole layer and which cross the magnetic circuit; and insulating layers electrically insulating the auxiliary magnetic pole layer and the main magnetic pole layer from the conductive coil layer. The insulating layers have flat surfaces formed at the sides further from the auxiliary magnetic pole layer, the front end portion of the main magnetic pole layer is provided on one of the flat surfaces, and the conductive coil layer is disposed under the main magnetic pole layer so that a part of the conductive coil layer opposes the front end portion of the main magnetic pole layer.
    Type: Application
    Filed: July 11, 2001
    Publication date: January 17, 2002
    Applicant: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Toshinori Watanabe, Toshihiro Kuriyama
  • Patent number: 6327116
    Abstract: A thin-film magnetic head has a magnetic lower core layer and a magnetic upper core layer formed on the lower core layer with a nonmagnetic gap layer provided therebetween, and the lower core layer and the upper core layer are opposed on an opposing surface which faces a recording medium. The upper core layer includes a leading region extending from the opposing surface towards the rear portion away from the recording medium and having a track width TW, a middle region extending from the leading region towards the rear portion and having a width larger than the track width TW, and a trailing region extending from the middle region towards the rear portion and having an increasing width. The edges at the boundary between the leading region and the middle region are rounded.
    Type: Grant
    Filed: June 21, 1999
    Date of Patent: December 4, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Toshinori Watanabe, Kiyoshi Sato
  • Patent number: 6307722
    Abstract: A longitudinal bias layer and an electrode layer are formed on a non-magnetic material layer. The longitudinal bias layer and the electrode layer are partially removed by an etching technique so that a narrow gap defining the track width Tw is formed in the longitudinal bias layer and the electrode layer. Furthermore, a three-layer film consisting of, from bottom to top, a magnetoresistance effect layer, a non-magnetic layer, and a transverse bias layer, or otherwise a spin valve film consisting of a free magnetic layer, a non-magnetic layer, a fixed magnetic layer and a bias layer is formed on the above structure. The three-layer film or the spin valve film is then partially removed by an etching technique so that the three-layer film or the spin valve film remains only in the above-described narrow gap formed in the longitudinal bias layer and the electrode layer.
    Type: Grant
    Filed: January 26, 1999
    Date of Patent: October 23, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Kiyoshi Sato, Yoshihiko Kakihara, Masamichi Saito, Toshihiro Kuriyama, Toshinori Watanabe
  • Publication number: 20010026419
    Abstract: The leak magnetic field generated from the upper core layer toward the upper magnetic pole layer can concentrate in the vicinity of the gap layer to suppress side-fringing from generating while increasing the overwrite, by making the saturation magnetic flux density Bs1 of the upper magnetic pole layer to be higher than the saturation magnetic flux density Bs2 of the upper core layer, and by directly bonding the upper core layer on the upper magnetic pole layer.
    Type: Application
    Filed: March 30, 2001
    Publication date: October 4, 2001
    Applicant: Alps Electric Co., Ltd
    Inventors: Toshinori Watanabe, Hisayuki Yazawa
  • Patent number: 6274256
    Abstract: A product (S×Bs) of a cross-sectional area of a tip portion of an upper core layer (S) (a thickness of a layer d1 by a track width Tw) and a saturation magnetic flux density thereof (Bs) is in a range of 1.5 to 10.5 &mgr;m2·T, and preferably in a range of 4.0 to 8.0 &mgr;m2·T. Further, a magnetic pole straight length L1 ranges from 3.5 to 7.6 &mgr;M. Thus, excellent NLTS and OW characteristics can be simultaneously obtained.
    Type: Grant
    Filed: February 1, 1999
    Date of Patent: August 14, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Toshinori Watanabe, Atsushi Sato, Akira Takahashi
  • Patent number: 6201465
    Abstract: A magnetoresistive sensor is fabricated as follows. First of all, first antiferromagnetic layers are created on the upper surfaces on both sides of a lower-gap layer, sandwiching a track width on the upper surface of the lower-gap layer. Then, a free magnetic layer, a nonmagnetic electrically conductive layer, a pinned magnetic layer and a second antiferromagnetic layer are stacked on the first antiferromagnetic layers and a portion on the track width one after another in the order the layers are enumerated. Since the free magnetic layer is created after the first antiferromagnetic layer, the free magnetic layer and the first antiferromagnetic layer are adhered to each other with a high degree of reliability. When the direction of magnetization in the free magnetic layer is changed by an external magnetic field, the electrical resistance of the magnetoresistive sensor also changes. The change in electrical resistance is, in turn, used for detecting the external magnetic field.
    Type: Grant
    Filed: November 2, 1999
    Date of Patent: March 13, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe, Kiyoshi Sato, Toshihiro Kuriyama
  • Patent number: 6198378
    Abstract: A magnetoresistive sensor fabricated by creating first antiferromagnetic layers on the upper surfaces of a lower-gap layer, the antiferromagnetic layer having first and second exposed portions separated by a track width formed by the upper surface of the lower-gap layer. Then, a free magnetic layer, a nonmagnetic electrically conductive layer, a pinned magnetic layer and a second antiferromagnetic layer are stacked on the first antiferromagnetic layers and a portion on the track width one after another. Since the free magnetic layer is created after the first antiferromagnetic layer, the free magnetic layer and the first antiferromagnetic layer are adhered to each other with a high degree of reliability. When the direction of magnetization in the free magnetic layer is changed by an external magnetic field, the electrical resistance of the magnetoresistive sensor also changes. The change in electrical resistance is, in turn, used for detecting the external magnetic field.
    Type: Grant
    Filed: September 4, 1996
    Date of Patent: March 6, 2001
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe, Kiyoshi Sato, Toshihiro Kuriyama
  • Patent number: 6153062
    Abstract: PtMn films are used as antiferromagnetic layers of a dual spin-valve type magnetoresistive sensor. An exchange anisotropic magnetic field is achieved regardless of whether the PtMn film is formed over or under the pinned magnetic layer. Also, an effective exchange anisotropic magnetic field is produced even with heat treatment at a relatively low temperature. Alternatively, a PtMn film is used as an antiferromagnetic layer of a spin-valve film laminate. The use of a PtMn film enables a sufficient exchange anisotropic magnetic field to be produced even with a relatively low heat treatment temperature and a relatively small film thickness. Therefore, the number of total layers of the spin-valve film laminate can be increased to increase a magnetoresistance ratio, and a total thickness of the spin-valve film laminate can be made relatively small.
    Type: Grant
    Filed: December 10, 1998
    Date of Patent: November 28, 2000
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe
  • Patent number: 6150046
    Abstract: A thin film magnetic head includes an upper core layer and a lower core layer which are made of an Fe--M--O alloy, an Fe--M--T--O alloy or an NI--Fe--X alloy so that the upper core layer has a high saturation magnetic flux density, low coercive force and high resistivity, and the lower core layer has a lower saturation magnetic flux density than the upper core layer, low coercive force, high resistivity, and a low magnetostriction constant. Also the lower core layer is formed so that the thickness gradually decreases toward both side ends, and a gap layer can be formed on the lower core layer to have a uniform thickness. Since the lower core layer is formed by sputtering, a material having excellent soft magnetic material can be used, thereby enabling recording at high frequency.
    Type: Grant
    Filed: January 30, 1998
    Date of Patent: November 21, 2000
    Assignee: Alps Electric Co., Ltd.
    Inventors: Toshinori Watanabe, Akira Takahashi, Fumihito Koike, Nobuhiro Hayashi, Yoshihiro Kanada, Kiyoshi Sato, Eiji Umetsu, Takashi Hatanai, Akihiro Makino
  • Patent number: 6128167
    Abstract: A spin-valve magnetoresistive element includes a hard bias layer formed on a pinned magnetic layer with a non-magnetic layer therebetween, and thus the magnetic field from the hard bias layer is efficiently applied into a free magnetic layer. Also, the pinned magnetic layer is not influenced by the hard bias layer because of the interposition of the non-magnetic layer. Accordingly, the pinned magnetic layer and the free magnetic layer are properly put into single magnetic domain states, and thus, Barkhausen noise is reduced and satisfactory micro-track-asymmetry can be obtained.
    Type: Grant
    Filed: May 19, 1998
    Date of Patent: October 3, 2000
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe
  • Patent number: RE37819
    Abstract: The present invention provides a magnetoresistive head wherein: a magnetoresistive film is created in a read-track region at the center of the magnetoresistive head; an antiferromagnetic film and a ferromagnetic film experiencing an exchange coupling magnetic field due to direct contact with the antiferromagnetic film are created on each end of the magnetoresistive film outside the read-track region in such a way that the ferromagnetic film is located beside the magnetoresistive film; a nonmagnetic intermediate film is created between the magnetoresistive film and the ferromagnetic film for preventing ferromagnetic coupling from being developed on a contact boundary surface between the magnetoresistive film and the ferromagnetic film and for making crystal orientations of the antiferromagnetic film and the ferromagnetic film uniform; and bias magnetization is applied to the magnetoresistive film by exchange coupling between the antiferromagnetic film and the ferromagnetic film.
    Type: Grant
    Filed: January 18, 2000
    Date of Patent: August 13, 2002
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe, Toshihiro Kuriyama
  • Patent number: RE37992
    Abstract: A magnetoresistive head including a magnetoresistive film formed in a read-track region, and antiferromagnetic and ferromagnetic films are formed on each end of the magnetoresistive film outside of the read-track region such that bias magnetization is applied to the magnetoresistive film by exchange coupling between the antiferromagnetic film and the ferromagnetic film. A nonmagnetic intermediate film is formed between the ferromagnetic film and the magnetoresistive film for preventing ferromagnetic coupling on a contact boundary surface between the ferromagnetic film and the magnetoresistive film. In accordance with another aspect, a magnetoresistive head includes an antiferromagnetic layer formed from an X—Mn alloy, where X is an element selected from the group consisting of Pt, Rh, Ru, Tr, and Pd. An interdiffusion layer is formed between the antiferromagnetic film and a ferromagnetic layer or a pinned magnetic layer by heat treatment.
    Type: Grant
    Filed: April 7, 1999
    Date of Patent: February 18, 2003
    Assignee: Alps Electric Co., Ltd.
    Inventors: Masamichi Saito, Toshinori Watanabe, Toshihiro Kuriyama