Patents by Inventor Kazuya Shimakawa
Kazuya Shimakawa 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: 7482070Abstract: A magnetic recording medium having high reliability is provided, in which concave portions between recording elements formed as convex portions of a concavo-convex pattern are approximately completely filled with a non-magnetic material. The magnetic recording medium is a plate-like body including: a substrate; a recording layer that is formed in a predetermined concavo-convex pattern over the substrate and includes recording elements for recording information formed as convex portions of the concavo-convex pattern; and the non-magnetic material filling concave portions between the recording elements. Side faces of the recording elements are inclined to face a surface of the plate-like body on a side toward which the recording elements 16 project in the concavo-convex pattern. An inclination angle of the side faces of the recording elements with respect to a direction perpendicular to that surface is smaller than 90° and 5° or more.Type: GrantFiled: April 27, 2005Date of Patent: January 27, 2009Assignee: TDK CorporationInventors: Mitsuru Takai, Yoshikazu Soeno, Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20080304175Abstract: A recording/reproducing apparatus includes: a rotary-type magnetic recording medium including a track pattern with concentric or spiral data recording tracks; a composite magnetic head including a reproducing element that reads magnetic signals from the medium and a recording element that writes magnetic signals on the medium; a control unit that moves the magnetic head over the medium to carry out tracking servo control on the reproducing element or the recording element to keep the element on a desired track; and a storage unit that stores offset information that specifies offsets for calculating an adjustment used to adjust a head position of the magnetic head during tracking servo control. The stored offset information specifies at least two different offsets per revolution of the medium. During tracking servo control, the control unit changes the adjustment at least once per revolution of the medium in accordance with offsets specified based on the offset information.Type: ApplicationFiled: February 25, 2008Publication date: December 11, 2008Applicant: TDK CORPORATIONInventors: Makoto MORIYA, Kazuya SHIMAKAWA
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Publication number: 20080237938Abstract: A method for manufacturing an information recording medium, a method of transferring a concavo-convex pattern, and a transfer apparatus are provided which are capable of curing a resin material with reliability even when using a light-transmitting stamper repeatedly. A stamper made of a light-transmitting resin, having a predetermined concavo-convex pattern formed on its transfer area, is inspected for an optical characteristic. The stamper is brought into contact with an energy-ray curable resin material applied to an object to be processed, thereby transferring the concavo-convex pattern to the resin material, and the resin material is irradiated with an energy ray through the stamper so that the resin material cures. The stamper is used a plurality of times to repeat these steps a plurality of times, thereby manufacturing a plurality of information recording media.Type: ApplicationFiled: March 27, 2008Publication date: October 2, 2008Applicant: TDK CORPORATIONInventors: Narutoshi Fukuzawa, Minoru Fujita, Daisuke Yoshitoku, Mitsuru Takai, Kazuya Shimakawa
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Patent number: 7423842Abstract: A magnetic recording medium including at least a disk substrate 1A, a magnetic recording layer 5 formed with a predetermined concavo-convex pattern on the disk substrate 1A, and a non-magnetic layer 6 filled into concave portions of the concavo-convex pattern, so as to have data track regions 20 and servo pattern regions 21. Due to the existence of concaves and convexes in the surface of each data track region 20, the foregoing problem is solved. On this occasion, arithmetical mean deviation of the assessed profile Ra of the surface of each data track region 20 is preferably not lower than 0.3 nm. The difference in surface level between each concave and each convex existing in the surface of the data track region 20 is preferably not larger than 6 nm.Type: GrantFiled: February 22, 2005Date of Patent: September 9, 2008Assignee: TDK CorporationInventors: Minoru Fujita, Mitsuru Takai, Kazuya Shimakawa
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Publication number: 20080212231Abstract: The magnetic recording medium includes a substrate and a recording layer formed in a predetermined concavo-convex pattern over the substrate, the recording layer including recording elements each formed as a convex portion of the recording layer. Surface steps are formed in an outer area including a radially outermost portion of a recording area. Each surface step is formed in such a manner that a portion over a concave portion between the recording elements is recessed toward the substrate to a level below a portion over the recording element. The surface steps are formed such that the recording area can be sectioned into an annular area adjoining the outer area and the outer area where height of the surface steps is larger than that in the annular area.Type: ApplicationFiled: January 3, 2008Publication date: September 4, 2008Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Kazuya Shimakawa
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Patent number: 7403353Abstract: The invention is directed to a magnetic recording/reproducing system wherein each burst pattern in discrete media is configured in a substantially trapezoidal shape (truncated quadrangular pyramid shape, and which satisfies given relations between W1, W2, Tp and Wr. W1 is the upper side of the trapezoidal shape in the track width direction, which corresponds to the surface of said convex-form magnetic recoding layer, W2 is the lower side of the trapezoidal shape in the track width direction, which corresponds to the bottom surface of said convex-form magnetic layer, Tp is the data track pitch at the data information recording portion, and Wr is the read width of the magnetic head, so that loads on burst pattern shape in medium fabrication processes can be far more reduced and far more precise position error signals can be obtained.Type: GrantFiled: January 18, 2006Date of Patent: July 22, 2008Assignee: TDK CorporationInventors: Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20080170318Abstract: The magnetic recording medium includes a substrate and a recording layer formed in a predetermined concavo-convex pattern over the substrate, and the recording layer includes recording elements each formed as a convex portion of the recording layer. Surface steps are formed in an inner area including a radially innermost portion of a recording area. Each surface step is formed in such a manner that a portion over a concave portion between the recording elements is recessed toward a substrate to a level below a portion over the recording element. The surface steps are formed such that the recording area can be sectioned into an annular area adjoining the inner area and the inner area where height of the surface steps is larger than that in the annular area.Type: ApplicationFiled: December 20, 2007Publication date: July 17, 2008Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Kazuya Shimakawa
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Publication number: 20080144230Abstract: A magnetic recording-reproducing apparatus includes: a magnetic recording medium in which portions corresponding to track portions serve as recording areas and in which portions between the recording areas serve as non-recording areas; and a magnetic head having a main pole and a side shield disposed on both sides of the main pole in a cross-track direction. In the magnetic recording-reproducing apparatus, following inequality (I) is satisfied: S>Tw/2+Gw ??(I) where Tw is a track width, Gw is a gap width, and S is a distance between the center of the main pole of the magnetic head and an edge on the main pole side of each of the side shields.Type: ApplicationFiled: December 11, 2007Publication date: June 19, 2008Applicant: TDK CORPORATIONInventors: Akimasa Kaizu, Yoshikazu Soeno, Kazuya Shimakawa
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Patent number: 7385785Abstract: A magnetic recording medium is provided, which includes a recording layer formed in a concavo-convex pattern to achieve high areal density and can ensure good recording and reproduction characteristics so as to provide high reliability. The magnetic recording medium has a substrate and a recording layer formed in the predetermined concavo-convex pattern over the substrate. The recording layer has a non-recording element and recording elements. The non-recording element is formed as convex portion of the concavo-convex pattern at an outer circumferential end and/or an inner circumferential end. The recording elements are formed as convex portions of the concavo-convex pattern in a region other than a region where the non-recording element is arranged.Type: GrantFiled: September 8, 2005Date of Patent: June 10, 2008Assignee: TDK CorporationInventors: Kazuhiro Hattori, Kazuya Shimakawa
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Publication number: 20080112046Abstract: Proposed is a technique of producing a magnetic garnet material of which the light absorption characteristics worsen little even though it is produced through LPE. The crucible for LPE is formed of a material containing Au. The amount of Au to be taken in single crystal formed in an Au crucible is smaller than that of Pt to be taken therein formed in a Pt crucible. As compared with Pt, the influence of Au on magnetic garnet film that increases the insertion loss in the film is small.Type: ApplicationFiled: December 21, 2007Publication date: May 15, 2008Applicant: TDK CorporationInventors: Atsushi Ohido, Tamotsu Sugawara, Kazuhito Yamasawa, Shinichiro Kakei, Kazuya Shimakawa, Katsunori Hosoya
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Publication number: 20080087631Abstract: A compact ion gun capable of flattening both sides of a substrate, an ion beam etching apparatus provided with the ion gun, an ion beam etching facility, an etching method using them, and a method for manufacturing a magnetic recording medium are provided. The ion gun includes a plasma generation source and an extraction electrode unit. The extraction electrode unit has: a first electrode unit including a portion of a plurality of electrode plates on a first side of a reference plane intersecting the electrode plates, the portion being inclined with respect to the reference plane so as to face an irradiation target area along the reference plane; and a second electrode unit including a portion of the electrode plates on a second side of the reference plane, the portion being inclined with respect to the reference plane so as to face the irradiation target area along the reference plane.Type: ApplicationFiled: October 10, 2007Publication date: April 17, 2008Applicant: TDK CORPORATIONInventors: Kazuhiro Hattori, Kazuya Shimakawa, Mitsuru Takai
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Patent number: 7352529Abstract: A magnetic recording medium including at least a disk substrate 1A, a magnetic recording layer 5 formed with a predetermined concavo-convex pattern on the disk substrate 1A, and a non-magnetic layer 6 filled into concave portions of the concavo-convex pattern, so as to have data track regions 20 and servo pattern regions 21. Due to the existence of concaves and convexes in the surface of each servo pattern region 21, the foregoing problem is solved. On this occasion, arithmetical mean deviation of the assessed profile Ra of the surface of each servo pattern region 21 is preferably not lower than 0.3 nm. The difference in surface level between each concave and each convex existing in the surface of the servo pattern region 21 is preferably not larger than 6 nm.Type: GrantFiled: February 22, 2005Date of Patent: April 1, 2008Assignee: TDK CorporationInventors: Mikiharu Hibi, Kazuhiro Hattori, Kazuya Shimakawa
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Patent number: 7333261Abstract: A of producing a magnetic garnet material of which the light absorption characteristics worsen little even though it is produced through LPE. The crucible for LPE is formed of a material containing Au. The amount of Au to be taken in single crystal formed in an Au crucible is smaller than that of Pt to be taken therein formed in a Pt crucible. As compared with Pt, the influence of Au on magnetic garnet film that increases the insertion loss in the film is small.Type: GrantFiled: April 7, 2006Date of Patent: February 19, 2008Assignee: TDK CorporationInventors: Atsushi Ohido, Tamotsu Sugawara, Kazuhito Yamasawa, Shinichiro Kakei, Kazuya Shimakawa, Katsunori Hosoya
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Publication number: 20070275270Abstract: An information medium which is capable of maintaining the protection capability by a lubricant for a long term. An information medium has a recording area and a non-recording area disposed on at least one surface of a disk-shaped base plate. The information medium is configured such that a lubricant exists on the one surface of the disk-shaped base plate. The recording area is configured such that a protective film formed of DLC exists above the recording layer. At least a surface-side portion of the non-recording area is formed of a resin material having a higher bonding ratio with respect to the lubricant than that of DLC.Type: ApplicationFiled: May 24, 2007Publication date: November 29, 2007Applicant: TDK CORPORATIONInventors: Kazuhiro HATTORI, Kazuya SHIMAKAWA
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Publication number: 20070196565Abstract: Provided is a method for manufacturing a magnetic recording medium that has a concavo-convex patterned recording layer, sufficient flatness, and excellent recording/reproducing properties. A filling material is deposited over a workpiece including a substrate; a recording layer formed over the substrate in a predetermined concavo-convex pattern of which convex portions are recording elements; and a detection material formed over the recording elements. Process gas is irradiated to the surface to remove a portion of the filling material and the detection material to flatten the surface. An element contained in the detection material removed and flying off is detected on the basis of its atomic mass number. The irradiation of the process gas is then stopped according to the detection result. The detection material contains an element selected from the group consisting of aluminum, yttrium, zirconium, niobium, rhodium, silver, terbium, tantalum, gold, bismuth, titanium, indium, and tungsten.Type: ApplicationFiled: February 22, 2007Publication date: August 23, 2007Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Kazuya Shimakawa
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Publication number: 20070139804Abstract: Data track pattern regions, in which data track patterns are formed by concave/convex patterns, and servo pattern regions, in which servo patterns are formed by concave/convex patterns, are provided on a magnetic recording medium so as to be alternately disposed in a circumferential direction. At least one predetermined region that differs to the data track pattern regions is provided between two servo pattern regions that are adjacent in a circumferential direction. A concave/convex pattern including a plurality of first convex parts formed continuously in a radial direction is formed in each predetermined region.Type: ApplicationFiled: November 8, 2006Publication date: June 21, 2007Applicant: TDK CORPORATIONInventors: Kuniyasu ITO, Makoto MORIYA, Kazuya SHIMAKAWA
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Publication number: 20070120292Abstract: There is provided a stamper on which stamper-side concave/convex patterns are formed and which is capable of manufacturing an information recording medium on which at least servo patterns are formed by concave/convex patterns. First convex parts that are continuously formed along a direction corresponding to a radial direction of the information recording medium are formed in the stamper-side concave/convex patterns.Type: ApplicationFiled: September 29, 2006Publication date: May 31, 2007Applicant: TDK CORPORATIONInventors: Kazuhiro HATTORI, Kazuya SHIMAKAWA
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Publication number: 20070115580Abstract: A recording/reproducing apparatus includes: a magnetic recording medium on which data track patterns are formed in data track pattern regions by a pattern with recording regions and non-recording regions and on which servo patterns are formed in servo pattern regions by the pattern; a recording head that writes signals on the medium; a reproducing head that reads signals written on the medium; and a control unit that controls the writing of signals by the recording head and the reading of signals by the reproducing head and measures a predetermined parameter for at least one of the recording head and the reproducing head by writing and reading measurement signals on the medium.Type: ApplicationFiled: November 8, 2006Publication date: May 24, 2007Applicant: TDK CORPORATIONInventors: Makoto MORIYA, Kazuya SHIMAKAWA, Kuniyasu ITO
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Publication number: 20070108163Abstract: A stamper has stamper-side concave/convex patterns formed thereupon and is capable of manufacturing an information recording medium on which data track patterns and servo patterns are formed by concave/convex patterns. A plurality of types of convex parts with different heights from a reference plane, which is set between a front surface and a rear surface of the stamper, to protruding ends of the convex parts are formed in the stamper-side concave/convex patterns. Second convex parts, at least one part of which has the height that is higher than the height of a highest first convex part out of the convex parts formed in regions corresponding to the data track patterns, are formed in regions corresponding to the servo patterns.Type: ApplicationFiled: September 29, 2006Publication date: May 17, 2007Applicant: TDK CORPORATIONInventors: Kazuhiro HATTORI, Kazuya SHIMAKAWA
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Publication number: 20070008639Abstract: The invention is directed to a magnetic recording/reproducing system wherein each burst pattern in discrete media is configured in a substantially trapezoidal shape (truncated quadrangular pyramid shape, and which satisfies given relations between W1, W2, Tp and Wr. W1 is the upper side of the trapezoidal shape in the track width direction, which corresponds to the surface of said convex-form magnetic recoding layer, W2 is the lower side of the trapezoidal shape in the track width direction, which corresponds to the bottom surface of said convex-form magnetic layer, Tp is the data track pitch at the data information recording portion, and Wr is the read width of the magnetic head, so that loads on burst pattern shape in medium fabrication processes can be far more reduced and far more precise position error signals can be obtained.Type: ApplicationFiled: January 18, 2006Publication date: January 11, 2007Applicant: TDK CorporationInventors: Katsumichi Tagami, Kazuya Shimakawa