Patents by Inventor Ikuya Tagawa
Ikuya Tagawa 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: 6624972Abstract: A magnetic head has a lower sub-magnetic pole and an upper sub-magnetic pole disposed to be adjacent to a moving magnetic disk. The lower sub-magnetic pole and the upper sub-magnetic pole are placed adjacent one another with a predetermined interval at an adjacent point to the magnetic disk. A magnetic field is generated between those magnetic poles so that the magnetic disk is magnetized. A soft magnetic film extending between the magnetic poles and a first non-magnetic film and a second non-magnetic film supporting the soft magnetic film are disposed between the magnetic poles.Type: GrantFiled: August 31, 2000Date of Patent: September 23, 2003Assignee: Fujitsu LimitedInventors: Syuji Nishida, Ikuya Tagawa
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Publication number: 20030174441Abstract: According to the present invention, a recording magnetic head suitable for increasing a surface recording density and having a large recording magnetic field and a small recording blur is provided. A lower magnetic pole layer and an upper magnetic pole layer opposing the lower magnetic pole layer are formed, and a lower sub magnetic pole composed of a plurality of magnetic layers is formed along a medium facing face on the lower magnetic pole layer. The lengths in a direction perpendicular to the medium facing face of the respective magnetic layers forming the lower sub magnetic pole are longer as the respective magnetic layers get further away from the upper magnetic pole layer.Type: ApplicationFiled: November 6, 2002Publication date: September 18, 2003Applicant: FUJITSU LIMITEDInventors: Tomoko Kutsuzawa, Ikuya Tagawa
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Patent number: 6614620Abstract: A thin film magnetic head includes an upper magnetic pole maintaining a constant thickness in a range determined by the so-called gap depth. A thinner film portion is defined in the upper magnetic pole in a range rearward of the range determined by the gap depth. The thinner film portion has a reduced thickness smaller than the constant thickness. The upper magnetic pole starts to enlarge the core width in the lateral direction at the rear end of the region determined by the so-called neck height. The neck height smaller than the gap depth serves to establish a reduction in the thickness of the upper magnetic pole after the upper magnetic pole gets larger in the lateral direction. A magnetic saturation can reliably be prevented at the thinner film portion in the upper magnetic pole. The front end of the upper magnetic pole is allowed to receive a larger quantity of a magnetic flux. It is possible to reliably enhance a magnetic field for recordation in the thin film magnetic head.Type: GrantFiled: February 6, 2001Date of Patent: September 2, 2003Assignee: Fujitsu LimitedInventors: Ikuya Tagawa, Tomoko Kutsuzawa, Hideo Niwa, Yukinori Ikegawa, Yoshinori Ohtsuka, Hiroshi Maeda, Takashi Sekikawa, Hiroki Fujimoto
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Publication number: 20030147183Abstract: A soft magnetic film includes a ferromagnetic layer. The ferromagnetic layer is laid over a non-magnetic substructure including ferromagnetic atoms. The uniaxial magnetic anisotropy may be established in the ferromagnetic layer. Since a magnetic property is not required in the substructure under the ferromagnetic layer, the soft magnetic film of this type may be utilized for purposes of wider variations.Type: ApplicationFiled: November 19, 2002Publication date: August 7, 2003Applicant: FUJITSU LIMITEDInventors: Shoji Ikeda, Takayuki Kubomiya, Ikuya Tagawa, Yuji Uehara
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Patent number: 6567239Abstract: A liquid resist is introduced between adjacent conductive lines of a coil pattern girdling around a magnetic core piece. When the liquid resist is cured, an insulating resin filler can be fixed between the adjacent conductive lines of the coil pattern. An insulating metallic layer is formed to extend over the insulting resin filler and the conductive lines of the coil pattern. Thereafter, the insulating metallic layer is subjected to a flattening grinding treatment until at least a part of the conductive line is exposed at a flattened surface. Since the liquid of the resist, of a higher fluidity, penetrates in every hole and corner between the adjacent conductive lines, the gap defined between the adjacent conductive lines is fully filled with the insulating material. No voids remain in the gap. The conductive line of the coil can be reliably prevented from corrosion or oxidation.Type: GrantFiled: November 20, 2000Date of Patent: May 20, 2003Assignee: Fujitsu LimitedInventors: Minoru Hasegawa, Yoshinori Ohtsuka, Yuji Uehara, Takashi Sekikawa, Hiroshi Maeda, Masahiro Kakehi, Ikuya Tagawa, Tomoko Kutsuzawa, Syuji Nishida
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Publication number: 20030090835Abstract: A liquid resist is introduced between adjacent conductive lines of a coil pattern girdling around a magnetic core piece. When the liquid resist is cured, an insulating resin filler can be fixed between the adjacent conductive lines of the coil pattern. An insulating metallic layer is formed to extend over the insulting resin filler and the conductive lines of the coil pattern. Thereafter, the insulating metallic layer is subjected to a flattening grinding treatment until at least a part of the conductive line is exposed at a flattened surface. Since the liquid of the resist, of a higher fluidity, penetrates in every hole and corner between the adjacent conductive lines, the gap defined between the adjacent conductive lines is fully filled with the insulating material. No voids remain in the gap. The conductive line of the coil can be reliably prevented from corrosion or oxidation.Type: ApplicationFiled: December 23, 2002Publication date: May 15, 2003Applicant: Fujitsu LimitedInventors: Minoru Hasegawa, Yoshinori Ohtsuka, Yuji Uehara, Takashi Sekikawa, Hiroshi Maeda, Masahiro Kakehi, Ikuya Tagawa, Tomoko Kutsuzawa, Syuji Nishida
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Patent number: 6510024Abstract: There is provided a magnetic head which is able to enhance the magnetic field intensity to be generated by shaping a magnetic pole, and a method of manufacturing the same. The method of manufacturing a magnetic head, comprising the steps of forming a lower recording magnetic pole and an upper recording magnetic pole, and trimming partially an elongated pole in the vicinity of a floating surface of the upper recording magnetic pole and an upper portion of the lower recording magnetic pole positioned below and around the elongated pole by an ion milling method, wherein a core width of the elongated pole can be adjusted.Type: GrantFiled: July 17, 2001Date of Patent: January 21, 2003Assignee: Fujitsu LimitedInventors: Yoshinori Otsuka, Ikuya Tagawa, Yukinori Ikegawa, Tomoko Kutsuzawa, Yuji Uehara, Minoru Hasegawa
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Patent number: 6507448Abstract: An information recording device which records information at a high recording density such that an error rate is reduced. In particular, an information recording device that includes a recording head, arranged near or to be close to the recording medium, for applying magnetic fields to the small regions when the recording head relatively moves with respect to the recording medium to pass on the small regions of the recording medium, and a recording head controller for controlling the recording head to cause the recording head to apply magnetic fields to the small regions in a free region of the recording medium in a standby state in which at least information is not recorded on the recording medium to uniform the directions of magnetization of the small regions so as to erase the information in the predetermined free region.Type: GrantFiled: December 14, 2000Date of Patent: January 14, 2003Assignee: Fujitsu LimitedInventors: Syuji Nishida, Ikuya Tagawa, Yuji Uehara
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Publication number: 20020150790Abstract: A soft magnetic film comprising Fe, Co, a metallic element (M), and oxygen (O) is provided. The soft magnetic film is represented by a composition formula of (Fe1-aCoa)xMyOz. The metallic element (M) is one selected from a group consisting of Al, B, Ga, Si, Ge, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Rh, Ru, Ni, Pd and Pt, or is an alloy composed of at least two selected from this group. The composition formula fulfills the following conditions: a=0.05-0.65; y=0.2-9 at %, z=1-12 at %, and y+z=<15 at %; and x=(100−y−z) at %. A crystal structure is formed by having a bcc phase as a principal phase. The bcc phase has a crystal grain not exceeding 50 nm in diameter. The bcc phase includes a solid solution of the metallic element (M) and the oxygen (O).Type: ApplicationFiled: September 21, 2001Publication date: October 17, 2002Applicant: FUJITSU LIMITEDInventors: Shoji Ikeda, Ikuya Tagawa, Yuji Uehara, Yoshinori Ohtsuka
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Publication number: 20020129875Abstract: An object of the present invention is to provide a recording head having a magnetic pole simultaneously possessing a high saturation magnetic flux density, a high permeability and a high electric resistivity, and the magnetic pole of the recording head is a polycrystalline film comprising Fe whose content is not less than 57.5 atomic % and not more than 94.5 atomic %; one or more kinds of elements selected from the element group of Al, B, Ga, Si, Ge, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and Rh, whose whole content is not less than 1 atomic % and not more than 15 atomic %; N whose content is not less than 0.5 atomic % and not more than 10 atomic %; and O whose content is not less than 1.5 atomic % and not more than 22.5 atomic %.Type: ApplicationFiled: February 12, 2002Publication date: September 19, 2002Applicant: FUJITSU LIMITEDInventors: Shoji Ikeda, Yuji Uehara, Ikuya Tagawa, Naoki Takeguchi, Masahiro Kakehi
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Publication number: 20020094454Abstract: A magnetic recording medium stable against heat of which high density recording can be attained is provided by employing a magnetic material such that coercive magnetic force in a recording magnetic layer increases with temperature rise.Type: ApplicationFiled: March 13, 2002Publication date: July 18, 2002Applicant: FUJITSU LIMITEDInventors: Ikuya Tagawa, Koji Matsumoto
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Publication number: 20020071224Abstract: A magnetoresistive transducer includes a magnetoresistive (MR) film interposed between domain control layers along the surface of a lower non-magnetic gap layer. Lead layers are formed on the domain control layers. An upper non-magnetic gap layer and an upper shield layer are sequentially formed to extend over the MR film and the lead layers. The upper shield layer is opposed to the surfaces of the MR element and the lead layers at a flat boundary or interface. The residual magnetization is supposed to exist in the upper shield layer in the direction of the magnetization established in the domain control layers after the upper shield layer has been subjected to the applied magnetic field for the magnetization of the domain control layers. The residual magnetization can be kept continuous along the flat interface of the upper shield layer. Any magnetic poles are hardly generated along the interface of the upper shield layer.Type: ApplicationFiled: March 14, 2001Publication date: June 13, 2002Applicant: FUJITSU LIMITEDInventors: Ikuya Tagawa, Kenichiro Yamada
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Publication number: 20020048116Abstract: A thin film magnetic head includes an upper magnetic pole maintaining a constant thickness in a range determined by the so-called gap depth. A thinner film portion is defined in the upper magnetic pole in a range rearward of the range determined by the gap depth. The thinner film portion has a reduced thickness smaller than the constant thickness. The upper magnetic pole starts to enlarge the core width in the lateral direction at the rear end of the region determined by the so-called neck height. The neck height smaller than the gap depth serves to establish a reduction in the thickness of the upper magnetic pole after the upper magnetic pole gets larger in the lateral direction. A magnetic saturation can reliably be prevented at the thinner film portion in the upper magnetic pole. The front end of the upper magnetic pole is allowed to receive a larger quantity of a magnetic flux. It is possible to reliably enhance a magnetic field for recordation in the thin film magnetic head.Type: ApplicationFiled: February 6, 2001Publication date: April 25, 2002Applicant: FUJITSU LIMITEDInventors: Ikuya Tagawa, Tomoko Kutsuzawa, Hideo Niwa, Yukinori Ikegawa, Yoshinori Ohtsuka, Hiroshi Maeda, Takashi Sekikawa, Hiroki Fujimoto
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Publication number: 20020024765Abstract: An upper magnetic pole layer extends forward over the surface of a non-magnetic gap layer from the central position of a swirly coil pattern. The upper magnetic pole layer is designed to get narrower in the forward direction so as to reach a medium-opposed surface at its tip end. A front magnetic pole piece is defined at the tip end of the upper magnetic pole layer. The front magnetic pole piece extends forward by a constant core width over the surface of the non-magnetic gap layer. The neck height near the trailing side can be defined by a length of the edges or ridgelines extending in parallel near the trailing side on the front magnetic pole piece. The upper magnetic pole layer starts getting broader in the core width from the position defined by the neck height. The reduction in the neck height near the trailing side below 1.0 &mgr;m, leads to a reduced leakage of the magnetic field from the trailing edges of the exposed surface of the upper magnetic pole layer at the medium-opposed surface.Type: ApplicationFiled: January 29, 2001Publication date: February 28, 2002Applicant: FUJITSU LIMITEDInventors: Tomoko Kutsuzawa, Ikuya Tagawa
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Publication number: 20010050830Abstract: There is provided a magnetic head which is able to enhance the magnetic field intensity to be generated by shaping a magnetic pole, and a method of manufacturing the same. The method of manufacturing a magnetic head, comprising the steps of forming a lower recording magnetic pole and an upper recording magnetic pole, and trimming partially an elongated pole in the vicinity of a floating surface of the upper recording magnetic pole and an upper portion of the lower recording magnetic pole positioned below and around the elongated pole by an ion milling method, wherein a core width of the elongated pole can be adjusted.Type: ApplicationFiled: July 17, 2001Publication date: December 13, 2001Applicant: Fujitsu LimitedInventors: Yoshinori Otsuka, Ikuya Tagawa, Yukinori Ikegawa, Tomoko Kutsuzawa, Yuji Uehara, Minoru Hasegawa
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Publication number: 20010043418Abstract: An information recording device which records information at a high recording density such that an error rate is reduced.Type: ApplicationFiled: December 14, 2000Publication date: November 22, 2001Applicant: FUJITSU LIMITEDInventors: Syuji Nishida, Ikuya Tagawa, Yuji Uehara
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Publication number: 20010043445Abstract: A thin film magnetic head includes: a lower magnetic pole (8); an upper magnetic pole (16) disposed to face the lower magnetic pole; a recording coil disposed between the lower magnetic pole and the upper magnetic pole, the recording coil being spaced from the both magnetic poles; and an upper tip sub-magnetic pole (22) provided at the side of the lower magnetic pole of the upper magnetic pole in the vicinity of a floating surface (ABS). In the first aspect, the upper magnetic pole and the upper tip sub-magnetic pole are disposed in such a manner that an end portion at the side of the floating surface of the upper magnetic pole recedes from an end portion at the side of the floating surface of the upper tip sub-magnetic pole. In the second aspect, a portion of the upper magnetic pole in the vicinity of the floating surface is formed to be narrower than the other portion of the pole, and to be wider than a core width of the upper tip sub-magnetic pole.Type: ApplicationFiled: March 9, 2001Publication date: November 22, 2001Applicant: FUJITSU LIMITEDInventors: Syuji Nishida, Ikuya Tagawa, Tomoko Kutsuzawa
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Patent number: 6282776Abstract: There is provided a magnetic head which is able to enhance the magnetic field intensity to be generated by shaping a magnetic pole, and a method of manufacturing the same. The method of manufacturing a magnetic head, comprising the steps of forming a lower recording magnetic pole and an upper recording magnetic pole, and trimming partially an elongated pole in the vicinity of a floating surface of the upper recording magnetic pole and an upper portion of the lower recording magnetic pole positioned below and around the elongated pole by an ion milling method, wherein a core width of the elongated pole can be adjusted.Type: GrantFiled: November 25, 1998Date of Patent: September 4, 2001Assignee: Fujitsu LimitedInventors: Yoshinori Otsuka, Ikuya Tagawa, Yukinori Ikegawa, Tomoko Kutsuzawa, Yuji Uehara, Minoru Hasegawa
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Publication number: 20010013992Abstract: A thin film magnetic head includes: a lower magnetic pole (8); an upper magnetic pole (16) disposed to face the lower magnetic pole; a recording coil disposed between the lower magnetic pole and the upper magnetic pole, the recording coil being spaced from the both magnetic poles; and an upper tip sub-magnetic pole (22) provided at the side of the lower magnetic pole of the upper magnetic pole in the vicinity of a floating surface (ABS). The upper tip sub-magnetic pole (22) is formed in such a manner that a core width (SW2) of a body portion thereof is larger than a core width (SW1) at the floating surface (ABS). When a position where the core width of the tip sub-magnetic pole (22) starts to spread is defined as a tip projection height (SH), the tip projection height is selected to be 0.Type: ApplicationFiled: March 9, 2001Publication date: August 16, 2001Applicant: FUJITSU LIMITEDInventors: Ikuya Tagawa, Syuji Nishida
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Patent number: 6094325Abstract: A spin valve head comprises a spin valve film having at least a pinned magnetic layer, a nonmagnetic metal layer, and a free magnetic layaer. The spin valve head further comprises a hard magnetic layer for controlling magnetic domains of the free magnetic layer, and electrode elements for supplying a sense current to the spin valve film, wherein the hard magnetic layer and the free magnetic layer are positioned not to overlap an orthographic projection of the hard magnetic layer in a thickness direction of the spin valve film with an orthographic projection of the free magnetic layer in the thickness direction of the spin valve film. According to such configuration, a single magnetic domain structure which does not generate a reverse magnetic field region throughout the overall surface of the free magnetic layer can be obtained, so that the hysteresis phenomenon is not caused in the spin valve head output. Therefore, the output with no noise can be derived.Type: GrantFiled: July 7, 1998Date of Patent: July 25, 2000Assignee: Fujitsu LimitedInventors: Ikuya Tagawa, Kenichiro Yamada, Yuji Uehara