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: 7158340Abstract: The burst pattern shape in a discrete medium is set to a shape (truncated quadrangular pyramid shape) having substantially trapezoidal shapes in a track width direction and in a track circumferential direction, respectively, and a predetermined relationship is satisfied among W1, W2, Tp, and Wr where W1 represents an upper side corresponding to the surface of a convex magnetic recording layer and W2 a lower side corresponding to the lower surface of the convex magnetic recording layer in the trapezoidal shape in the track width direction, Tp represents a data track pitch of a data information recording portion, and Wr represents a read width of a magnetic head. Therefore, the burst pattern shape makes it possible to largely reduce a production load in processing and still to obtain an accurate position error signal.Type: GrantFiled: April 22, 2005Date of Patent: January 2, 2007Assignee: TDK CorporationInventors: Katsumichi Tagami, Yoshikazu Soeno, Kazuya Shimakawa, Hiroki Matsukuma
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Patent number: 7133189Abstract: 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: GrantFiled: February 14, 2003Date of Patent: November 7, 2006Assignee: TDK CorporationInventors: Atsushi Ohido, Tamotsu Sugawara, Kazuhito Yamasawa, Shinichiro Kakei, Kazuya Shimakawa, Katsunori Hosoya
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Publication number: 20060203386Abstract: In a magnetic recording medium including a servo pattern region having a servo pattern formed of a concave/convex pattern having convex portions and concave portions and a data recording region, the region having a data track pattern, the convex portions are formed in an address pattern region of the servo pattern region such that the maximum opening lengths, which are located in the respective same radius regions of the respective opening lengths along the rotating direction of a substrate of the concave portions constituting the concave/convex pattern are set to first lengths that are double the minimum opening lengths along the rotating direction of the concave portions in the respective same radius regions. With this arrangement, the magnetic recording medium can securely read a magnetic signal and has a servo pattern having excellent surface smoothness.Type: ApplicationFiled: November 3, 2005Publication date: September 14, 2006Applicant: TDK CorporationInventors: Yoshikazu Soeno, Kazuya Shimakawa
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Publication number: 20060198052Abstract: On a magnetic recording medium, a servo pattern is formed in a servo pattern region on at least one surface of a substrate by a concave/convex pattern including a convex part, at least protruding end part of which is formed of magnetic material, and a concave part. The servo pattern region includes an address pattern region and a burst pattern region, wherein the convex part is formed in the servo pattern region so that a larger of an inscribed circle with a largest diameter out of inscribed circles on an open surface of the concave part formed in the address pattern region and an inscribed circle with a largest diameter out of inscribed circles on an open surface of the concave part formed in the burst pattern region is an inscribed circle with a largest diameter out of inscribed circles on an open surface of the concave part formed in the servo pattern region.Type: ApplicationFiled: February 22, 2006Publication date: September 7, 2006Applicant: TDK CorporationInventors: Yoshikazu Soeno, Kazuya Shimakawa
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Publication number: 20060187546Abstract: 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: April 7, 2006Publication date: August 24, 2006Applicant: TDK CorporationInventors: Atsushi Ohido, Tamotsu Sugawara, Kazuhito Yamasawa, Shinichiro Kakei, Kazuya Shimakawa, Katsunori Hosoya
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Publication number: 20060188751Abstract: A magnetic recording medium is provided that includes a recording layer having recording elements formed as convex portions and a filling material filled within the concave portions between the recording elements. The medium is highly reliable and has a surface less liable to damages when a magnetic head contacts the surface, so that good recording/reproducing characteristics are ensured. The magnetic recording medium includes a recording layer formed in a predetermined concavo-convex pattern over a substrate and having recording elements formed as convex portions in the concavo-convex pattern and a filling material filled within the concave portions between the recording elements. The filling material is substantially composed of Si and O, and the ratio of the number of O atoms to the number of Si atoms is equal to or more than 1.5 and less than 2.Type: ApplicationFiled: January 19, 2006Publication date: August 24, 2006Applicant: TDK CORPORATIONInventors: Shuichi Okawa, Mitsuru Takai, Kazuya Shimakawa
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Publication number: 20060132970Abstract: A perpendicular magnetic recording/reproducing device that can suppress broadening of recording magnetic fields and that is capable of effective application of magnetic field to a recording target track is provided. The device includes a magnetic recording medium having a soft magnetic layer and a recording layer having a perpendicular magnetic anisotropy formed in this order over a substrate, and a magnetic head. The soft magnetic layer is formed with a concavo-convex pattern in which at least part of regions corresponding to tracks of the recording layer protrudes toward the recording layer, and convex portions are provided with the magnetic anisotropy in the circumferential direction of the tracks. The magnetic head includes a main pole for generating a recording magnetic field, and a return pole to which the magnetic field returns, the main pole and the return pole being arranged side by side in a track width direction.Type: ApplicationFiled: December 9, 2005Publication date: June 22, 2006Applicant: TDK CORPORATIONInventors: Mitsuru Takai, Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20060124585Abstract: A method for manufacturing a magnetic recording medium is provided, which can manufacture a magnetic recording medium that includes a recording layer having a concavo-convex pattern and has a sufficiently flat surface. The method includes the steps of: forming an object to be processed including a recording layer having a predetermined concavo-convex pattern formed over a substrate and a first mask layer (temporary underlying material) formed at least on recording elements (convex portions) of the recording layer; depositing a filling material on the object to be processed to fill concave portions; removing a part of the filling material by dry etching to expose at least side faces of the first mask layer; and removing the first mask layer by an etching method in which an etching rate of the first mask layer is higher than that of the filling material to flatten a surface.Type: ApplicationFiled: December 9, 2005Publication date: June 15, 2006Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Shuichi Okawa, Kazuya Shimakawa
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Publication number: 20060098343Abstract: 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: ApplicationFiled: September 8, 2005Publication date: May 11, 2006Applicant: TDK CORPORATIONInventors: Kazuhiro Hattori, Kazuya Shimakawa
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Publication number: 20060040140Abstract: A perpendicular recording type, magnetic recording medium having a soft magnetic layer and a magnetic recording/reproducing apparatus including such a magnetic recording medium are provided. The magnetic recording medium allows the recording magnetic field to be efficiently applied to a track for recording while restricting the extent of the recording magnetic field. The magnetic recording medium has a soft magnetic layer and a recording layer formed in this order on a substrate. The soft magnetic layer has its part on the opposite side to the substrate formed in a concavo-convex pattern. The recording layer is oriented to have magnetic anisotropy in the direction perpendicular to the surface. A fixing layer for fixing the magnetic anisotropy of the soft magnetic layer in a predetermined direction parallel to the surface is provided between the recording layer and the soft magnetic layer.Type: ApplicationFiled: August 10, 2005Publication date: February 23, 2006Applicant: TDK CORPORATIONInventors: Akimasa Kaizu, Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20060029834Abstract: A magnetic recording medium in which a recording layer is formed in a predetermined concavo-convex pattern and recording and reproducing apparatus comprising the magnetic recording medium are disclosed. The magnetic recording medium has a high areal density and high reliability since the occurrence of a crash of a magnetic head is suppressed. The magnetic recording medium comprises a recording layer formed over a substrate in a predetermined concavo-convex pattern to form recording elements as a convex portion of the concavo-convex pattern and a non-magnetic filler element filled in a concave portion between the recording elements. In this configuration, the top surface of the filler element is formed in a shape partially recessed toward the substrate side to form a groove having a width smaller than the width of the concave portion on the surface of the magnetic recording medium.Type: ApplicationFiled: July 25, 2005Publication date: February 9, 2006Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Kazuya Shimakawa
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Publication number: 20050287397Abstract: A magnetic recording medium is provided which has good recording/reproducing characteristics with a recording layer divided in a number of recording elements by a predetermined concavo-convex pattern, and a manufacturing method that enables efficient manufacture of such a magnetic recording medium. The magnetic recording medium includes a substrate, a soft magnetic layer formed over the substrate, a recording layer formed over the soft magnetic layer such as to have magnetic anisotropy in a direction perpendicular to surface, and being divided in a number of recording elements by a predetermined concavo-convex pattern, and a non-magnetic intermediate layer formed between the recording layer and the soft magnetic layer. The recording elements are formed to have a predetermined track shape in a data region.Type: ApplicationFiled: May 24, 2005Publication date: December 29, 2005Applicant: TDK CORPORATIONInventors: Yoshikazu Soeno, Mitsuru Takai, Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20050286155Abstract: The burst pattern shape in a discrete medium is set to a shape (truncated quadrangular pyramid shape) having substantially trapezoidal shapes in a track width direction and in a track circumferential direction, respectively, and a predetermined relationship is satisfied among W1, W2, Tp, and Wr where W1 represents an upper side corresponding to the surface of a convex magnetic recording layer and W2 a lower side corresponding to the lower surface of the convex magnetic recording layer in the trapezoidal shape in the track width direction, Tp represents a data track pitch of a data information recording portion, and Wr represents a read width of a magnetic head. Therefore, the burst pattern shape makes it possible to largely reduce a production load in processing and still to obtain an accurate position error signal.Type: ApplicationFiled: April 22, 2005Publication date: December 29, 2005Applicant: TDK CorporationInventors: Katsumichi Tagami, Yoshikazu Soeno, Kazuya Shimakawa, Hiroki Matsukuma
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Publication number: 20050243467Abstract: 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: ApplicationFiled: April 27, 2005Publication date: November 3, 2005Applicant: TDK CORPORATIONInventors: Mitsuru Takai, Yoshikazu Soeno, Katsumichi Tagami, Kazuya Shimakawa
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Publication number: 20050233176Abstract: In an information recording medium where respective concave parts of a magnetic layer, which is formed on at least one side e of a substrate and in which a predetermined convex/concave pattern has been formed, are filled with non-magnetic material and non-magnetic layers are formed by the non-magnetic material in at least partial regions of respective upper surfaces of respective convex parts of the magnetic layer, the non-magnetic layers are formed so that parts thereof protrude further in a direction in which the convex parts protrude than other parts of the non-magnetic layers.Type: ApplicationFiled: March 22, 2005Publication date: October 20, 2005Applicant: TDK CorporationInventors: Mitsuru Takai, Yoshikazu Soeno, Katsumichi Tagami, Kazuya Shimakawa, Takahiro Suwa
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Publication number: 20050213239Abstract: 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: ApplicationFiled: February 22, 2005Publication date: September 29, 2005Applicant: TDK CorporationInventors: Mikiharu Hibi, Mitsuru Takai, Kazuya Shimakawa
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Publication number: 20050191526Abstract: 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: ApplicationFiled: February 22, 2005Publication date: September 1, 2005Applicant: TDK CorporationInventors: Minoru Fujita, Mitsuru Takai, Kazuya Shimakawa
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Publication number: 20030219261Abstract: 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: February 14, 2003Publication date: November 27, 2003Applicant: TDK CorporationInventors: Atsushi Ohido, Tamotsu Sugawara, Kazuhito Yamasawa, Shinichiro Kakei, Kazuya Shimakawa, Katsunori Hosoya