Patents by Inventor Naoki Koyama
Naoki Koyama 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: 6011674Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-denisity recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.Type: GrantFiled: April 2, 1996Date of Patent: January 4, 2000Assignee: Hitachi, Ltd.Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
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Patent number: 5850326Abstract: In a composite magnetic head comprising a magnetoresistive read head including a magnetic thin film having a magnetoresistive effect and soft magnetic members interposing the soft magnetic film between them through a non-magnetic insulation layer, an induction type write head including poles formed in a moving direction of a medium and a conductor crossing the poles, and disposed in the proximity of the magnetoresistive head, and a substrate supporting these heads, part of a floating surface inclusive of the magnetic head constituent members has recesses and the read/write operations to and from the medium are effected by the portion interposed by these recesses.Type: GrantFiled: February 7, 1994Date of Patent: December 15, 1998Assignee: Hitachi, Ltd.Inventors: Hisashi Takano, Naoki Koyama, Hideo Tanabe, Eijin Moriwaki, Isamu Yuito, Kazuo Shiiki, Tsuyoshi Ohnishi, Tohru Ishitani, Toshio Kobayashi, Hideo Todokoro, Chiaki Ishikawa
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Patent number: 5808843Abstract: A magnetoresistance effect reproduction head which comprises a magnetoresistive layer having a central sensing region and an end domain control region and formed into a thin film of a ferromagnetic material, a hard magnetic layer overlapping with the end domain control region in direct contact therewith and formed into a thin film of a hard magnetic material, a magnetic field and a longitudinal magnetic bias field by ferromagnetic exchange coupling is generated for maintaining the central sensing region of the magnetoresistive layer in single domain state.Type: GrantFiled: May 29, 1992Date of Patent: September 15, 1998Assignee: Hitachi, Ltd.Inventors: Toshio Kobayashi, Isamu Yuito, Masahiro Kitada, Noboru Shimizu, Naoki Koyama
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Patent number: 5726837Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.Type: GrantFiled: October 24, 1994Date of Patent: March 10, 1998Assignee: Hitachi, Ltd.Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
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Patent number: 5719729Abstract: In an inductive-write, magnetoresistive-read type magnetic head having a magnetoresistive read head and an inductive write head superimposed on each other, the magnetic center of the read head is made more coincident with the physical center of the write head by a changing of a magnetization direction of a magnetoresistive element. The recording/reproducing apparatus using this magnetic head can thus have a good S/N ratio even if the track width is narrow.Type: GrantFiled: December 15, 1992Date of Patent: February 17, 1998Assignee: Hitachi, Ltd.Inventors: Naoki Koyama, Yoshihiro Hamakawa, Isamu Yuitoo, Kanji Kawakami, Kazuo Shiiki, Masahiro Kitada
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Patent number: 5521005Abstract: In a magnetic head whose recording and reproduction sections are separated, the magnetoresistive element constituting the reproduction head has a structure comprising a soft magnetic film, a spacer metallic film, and a magnetoresistive film and uses a high-performance soft magnetic film whose composition is Ni--Fe--Ru, Ni--Fe--Ru--M (M: fourth element), Ni--Fe--Ta or Ni--Fe--Ta--M (M: fourth element) and which has low coercivity, low magnetostriction, high specific resistance, high saturation magnetization, low magnetoresistivity and high corrosion resistance, this invention provides a recording-reproduction separation type magnetic head comprising a soft magntic bias film which is high magnetic performance, low production cost, and high corrosion resistance.Type: GrantFiled: November 25, 1992Date of Patent: May 28, 1996Assignee: Hitachi, Ltd.Inventors: Masahiro Kitada, Noboru Shimizu, Naoki Koyama
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Patent number: 5461526Abstract: A magnetoresistive read head includes a magnetoresistive layer having a central active region and end domain control regions, an electrode layer connected to both ends of the magnetoresistive layer, a pattern for providing a transverse bias to the magnetoresistive layer, a soft magnetic film provided on both sides of the magnetoresistive layer for magnetically shielding the magnetoresistive layer, and a substrate for supporting the magnetoresistive layer, pattern and soft magnetic film. A distance between the two end domain control regions of the magnetoresistive layer indicative of a length of the central active region is smaller than a distance between inner end faces of the electrode layer and the distance between the inner end faces of the magnetoresistive substantially corresponds to a read track width.Type: GrantFiled: March 24, 1993Date of Patent: October 24, 1995Assignee: Hitachi, Ltd.Inventors: Yoshihiro Hamakawa, Toshio Kobayashi, Naoki Koyama, Masahiro Kitada
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Patent number: 5390061Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magneto-resistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.Type: GrantFiled: June 5, 1991Date of Patent: February 14, 1995Assignee: Hitachi, Ltd.Inventors: Ryoichi Nakatani, Masahiro Kitada, Naoki Koyama, Isamu Yuito, Hisashi Takano, Eijin Moriwaki, Mikio Suzuki, Masaaki Futamoto, Fumio Kugiya, Yoshibumi Matsuda, Kazuo Shiiki, Yoshinori Miyamura, Kyo Akagi, Takeshi Nakao, Hirotsugu Fukuoka, Takayuki Munemoto, Tokuho Takagaki, Toshio Kobayashi, Hideo Tanabe, Noboru Shimizu
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Patent number: 5337203Abstract: A magnetoresistive head having a structure based on a two-layer film having a first film exhibiting a magnetoresistive effect and a second film comprising Nb and at least one element selected from the group consisting of Ti, Cr, Mo, Zr, W, Pt, Re, V, Hf, Ta, Rh, Ni and Ru as an additive element.Type: GrantFiled: April 27, 1992Date of Patent: August 9, 1994Assignee: Hitachi, Ltd.Inventors: Masahiro Kitada, Hideo Tanabe, Noboru Shimizu, Naoki Koyama, Toshio Kobayashi
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Patent number: 5287237Abstract: In order to prevent generation of Barkhausen noise of a magnetoresistance-effect element, a thin antiferromagnetic film formed of Fe-Mn-X alloy containing a third alloying element X (which serves to improve corrosion resistance of Fe-Mn alloy) by 0.1 to 20 atomic % is disposed in adjacent to a thin permalloy film. The element X is selected from the group consisting of Ir, Ru, Zr, Nb, Si, Ge, V, Co, Pt and Pd. It is particularly recommended to employ Ir of 4 to 15 atomic % or Ru of 5.5 to 15 atomic % as the element X. When one or more alloying element selected from Ru, Rh, Pt, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ni, Cu, Al, Si and Ge is added to Fe and Mn which are essential components of the Fe-Mn-X alloy in addition to the element X, corrosion resistance of the alloy is improved more sufficiently.Type: GrantFiled: March 12, 1991Date of Patent: February 15, 1994Assignee: Hitachi, Ltd.Inventors: Masahiro Kitada, Noboru Shimizu, Hideo Tanabe, Ryoichi Nakatani, Isamu Yuito, Naoki Koyama
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Patent number: 5212609Abstract: A magnetoresistive head is disclosed. It comprises a lower gap film, a magnetoresistive film, a bias film, an electrode, an upper gap film, and upper shield film provided in sequence on a substrate. A protective film is provided under the upper shield film to prevent the upper gap film and electrode from the undesirable etching during patterning the upper shield film.Type: GrantFiled: November 15, 1991Date of Patent: May 18, 1993Assignee: Hitachi, Ltd.Inventors: Isamu Yuito, Makoto Morijiri, Tooru Takeura, Naoki Koyama, Masahiro Kitada
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Patent number: 5168409Abstract: The magnetic layer of a head structure can satisfy the characteristics of both the magnetic shield layer and magnetic pole layer for recording by bringing the combined upper part and lower part of the magnetic layer respectively into conformity with the widths necessary for the shield layer and for the magnetic pole, e.g., specifically, by disposing a taper or more specifically a step shape to the section of the magnetic layer to have the dimension of the upper part of the magnetic layer different from that of the lower part. The width of the magnetic layer facing one of the recording magnetic poles can be brought into conformity with the track width. Accordingly, the flux at the time of a write operation concentrates on the track width portion and hence, side writing of the recording head can be reduced. On the other hand, the width of the magnetic head on the opposed side to the magnetoresistive sensor can be extended sufficiently to fully cover the sensor.Type: GrantFiled: February 8, 1990Date of Patent: December 1, 1992Assignee: Hitachi, Ltd.Inventors: Naoki Koyama, Hisashi Takano, Eijin Moriwaki, Kazuo Shiiki
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Patent number: 5126907Abstract: A thin film magnetic head has a first magnetic core member carried by a substrate, a gap layer formed on the first magnetic core member, and a second magnetic core member formed in a spaced relation with the first magnetic core member. The second magnetic core member is coupled to the first magnetic core member to form a magnetic path and to have an end portion of the gap layer sandwiched by gap defining portions of the first and second magnetic core members. A coil conductor is wound about the magnetic path. In one embodiment, the first magnetic core member includes a first magnetic layer made of a magnetic material having stable magnetic properties during heat treatment and the second magnetic core member includes a second magnetic layer made of a material having a saturation flux density higher than that of the material of the first magnetic core member.Type: GrantFiled: May 21, 1990Date of Patent: June 30, 1992Assignee: Hitachi, Ltd.Inventors: Yoshihiro Hamakawa, Isamu Yuito, Hisashi Takano, Naoki Koyama, Eijin Moriwaki, Shinobu Sasaki, Kazuo Shiiki
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Patent number: 4922360Abstract: A magnetic head includes a magnetoresistance element having the form of a loop and provided with a gap at a first portion opposite to a second portion confronting a magnetic recording medium, a coil conductor formed around the first portion of the magnetoresistance element for applying a bias magnetic field to the second portion of the magnetoresistance element in the direction of width of a track on the magnetic recording medium, and a lead conductor attached to the magnetoresistance element to cause a current which is necessary for detecting a signal recorded on the magnetic recording medium, to flow through the second portion of the magnetoresistance element, and formed together with the coil conductor as one body so that a part of a current supplied to the lead conductor flows through the coil conductor.Type: GrantFiled: September 21, 1988Date of Patent: May 1, 1990Assignee: Hitachi, Ltd.Inventors: Hisashi Takano, Naoki Koyama, Isamu Yuito, Kazuo Shiiki, Hideo Tanabe
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Patent number: 4772505Abstract: The inclination angle, in the conductor pattern end portion of a magnetic bubble memory element having a bubble diameter of up to 1.2 .mu.m, can be remarkably reduced by employing a polymer resin, having fluidity in a curing process, as the insulation film under the conductor pattern, so that the transfer margin is greatly improved.Type: GrantFiled: August 18, 1986Date of Patent: September 20, 1988Assignee: Hitachi, Ltd.Inventors: Haruhiko Matsuyama, Fusaji Shoji, Hiroshi Umezaki, Masatoshi Takeshita, Naoki Koyama, Ryo Suzuki
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Patent number: 4503517Abstract: A magnetic bubble memory device comprises an ion-implanted region for information storage formed in a surface of a magnetic material layer and a permalloy transfer path formed near an ion implantation transfer path defined by the edge of the ion-implanted region for reading information from the ion implantation transfer path or writing information in the ion implantation transfer path. The ion implantation depth in a portion of the ion-implanted region near the permalloy transfer path is continuously changed to provide an inclined edge of the ion-implanted region.Type: GrantFiled: October 19, 1983Date of Patent: March 5, 1985Assignee: Hitachi, Ltd.Inventors: Hiroshi Umezaki, Naoki Koyama, Yooji Maruyama, Yutaka Sugita
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Patent number: 4502916Abstract: Fine patterns are formed by a process wherein a workpiece is spin coated with a heat-resistant resin layer, this resin layer is spin coated with an organotitanium or titanium oxide layer, a resist pattern is formed on the organotitanium or titanium oxide layer, the organotitanium or titanium oxide layer is etched by ion etching with the resist pattern as a mask, and finally, the resin layer is etched by using the etched organotitanium or titanium oxide layer as a mask.Type: GrantFiled: May 3, 1984Date of Patent: March 5, 1985Assignee: Hitachi, Ltd.Inventors: Hiroshi Umezaki, Naoki Koyama, Yoozi Maruyama, Yutaka Sugita
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Patent number: 4415262Abstract: A photomask is disclosed which is suitable for use in the one-mask method capable of forming a plurality of patterns with one exposure, and in which an opaque pattern having a predetermined form and a semi-transparent pattern having another predetermined form are formed on a transparent substrate, and the semi-transparent pattern is formed of an opaque film having a large number of fine through holes.Type: GrantFiled: January 18, 1982Date of Patent: November 15, 1983Assignee: Hitachi, Ltd.Inventors: Naoki Koyama, Youji Maruyama, Hiroshi Umezaki, Norikazu Tsumita, Yutaka Sugita
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Patent number: 4354203Abstract: In a television camera, a connection shaft for connecting a zoom operation flexible shaft and a focusing flexible shaft is rotatably attached to a lens holding member and is downwardly projected therefrom, with an engagement mechanism being provided in the lens holding member so as to prevent the zoom and focus movements of the lens when the connection shaft is stored in the lens holding member. A joint mechanism eliminates the necessity for the flexible shaft to extend perpendicularly from the camera during operation.Type: GrantFiled: May 15, 1980Date of Patent: October 12, 1982Assignee: Canon Kabushiki KaishaInventor: Naoki Koyama