Patents by Inventor Takahiro Suwa
Takahiro Suwa 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: 20110181984Abstract: The recording layer is made of both magnetic particles containing Co, Cr, and Pt and a nonmagnetic material containing Cr present among the magnetic particles. The recording element has an uneven Cr distribution such that the ratio of the number of Cr atoms that constitute the recording element to the total number of Co, Cr, and Pt atoms that constitute the recording element is less at the sidewall portion of the recording element than at the center portion of the recording element. The relationships given by Expressions (I) and (II) below are satisfied; Hnc<Hns??(I), and Hnc/Hcc<Hns/Hcs??(II) where Hns is the nucleation magnetic field of the sidewall portion of the recording element, Hnc is the nucleation magnetic field of the center portion of the recording element, Hcs is the coercive force of the sidewall portion, and Hcc is the coercive force of the center portion.Type: ApplicationFiled: January 20, 2011Publication date: July 28, 2011Applicant: TDK CORPORATIONInventors: Shuichi OKAWA, Narutoshi FUKUZAWA, Takahiro SUWA, Kazuhiro HATTORI, Yoshinori UCHIYAMA
-
Patent number: 7940494Abstract: 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: GrantFiled: January 3, 2008Date of Patent: May 10, 2011Assignee: TDK CorporationInventors: Takahiro Suwa, Kazuya Shimakawa
-
Publication number: 20110024388Abstract: A method for manufacturing a magnetic recording medium is provided which can sufficiently reduce variations in surface roughness even in the simultaneous presence of a region of a relatively wide concave and convex portion and a region of a relatively narrow concave and convex portion in the recording layer. The method includes the steps of etching a recording layer based on a (first) mask layer to process it in a concavo-convex pattern, and depositing a filler over the recording layer and the mask layer to fill a concave portion with the filler. In between those steps, provided is the step of removing part of the first mask layer over a recording element (a convex portion of the recording layer) by dry etching in which an etching rate for the mask layer is higher than that for the recording layer so that the mask layer remains over the recording element.Type: ApplicationFiled: July 23, 2010Publication date: February 3, 2011Applicant: TDK CORPORATIONInventors: Takahiro SUWA, Narutoshi Fukuzawa, Shuichi Okawa, Yoshinori Uchiyama
-
Publication number: 20100239888Abstract: A magnetic recording medium is provided in which recording elements and concave portions have a clear difference in terms of magnetism at the boundaries therebetween, and which has favorable production efficiency. The magnetic recording medium includes a substrate; a recording layer formed in a predetermined concavo-convex pattern over the substrate, convex portions of the concavo-convex pattern serving as recording elements; and a filler portion filling a concave portion between the recording elements. A center part of a bottom surface of the concave portion protrudes from edge parts of the bottom surface of the concave portion in a direction away from the substrate.Type: ApplicationFiled: March 8, 2010Publication date: September 23, 2010Applicant: TDK CORPORATIONInventors: Yoshinori Uchiyama, Takahiro Suwa, Narutoshi Fukuzawa, Kazuya Shimakawa
-
Publication number: 20100195237Abstract: A magnetic recording medium has data track patterns formed by concave/convex patterns in data recording regions on at least one surface of a substrate and servo patterns formed by concave/convex patterns in servo pattern regions between the data recording regions. The concave/convex patterns include convexes, at least protruding end portions of which are formed of magnetic material, and concaves. A burst pattern region of each servo pattern region includes N (where N is at least two) burst regions, in which burst patterns, where plural burst signal unitary parts are aligned along a direction of rotation, are formed as the servo patterns. The burst signal unitary parts formed in M (where M is no greater than (N?1)) out of the N burst regions are concaves, and the burst signal unitary parts formed in L (where L is equal to (N?M)) out of the N burst regions are convexes.Type: ApplicationFiled: February 2, 2010Publication date: August 5, 2010Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Narutoshi Fukuzawa
-
Patent number: 7740903Abstract: A method for manufacturing magnetic recording media is provided, by which a magnetic recording medium that has a recording layer formed in a concavo-convex pattern, a sufficiently flat surface, and good recording/reproducing properties can be manufactured. The method includes the steps of: depositing a first filling material over a workpiece to cover recording elements formed as convex portions of the concavo-convex pattern, and to fill at least part of a concave portion; depositing a detection material over the first filling material; depositing a second filling material over the detection material; and irradiating a surface of the workpiece with a process gas to flatten the surface. In the flattening step, a component of the detection material removed from and flying off the workpiece is detected to stop the irradiation with the process gas based on a result of detecting the component of the detection material.Type: GrantFiled: February 21, 2007Date of Patent: June 22, 2010Assignee: TDK CorporationInventors: Takahiro Suwa, Kazuhiro Hattori, Shuichi Okawa
-
Patent number: 7741229Abstract: 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: GrantFiled: December 9, 2005Date of Patent: June 22, 2010Assignee: TDK CorporationInventors: Takahiro Suwa, Shuichi Okawa, Kazuya Shimakawa
-
Patent number: 7682711Abstract: A magnetic recording medium is provided which includes a recording layer formed in a concavo-convex pattern including recording elements formed as convex portions, provides a good flying performance of a magnetic head, and has high reliability. A magnetic recording and reproducing apparatus including that magnetic recording medium and a manufacturing method of that magnetic recording medium are also provided. The magnetic recording medium includes: the recording layer formed in a predetermined concavo-convex pattern over a substrate, the recording elements being formed as convex portions of the concavo-convex pattern; filling elements with which concave portions between the recording elements are filled; a conductive film which has a smaller electric resistivity than the filling elements and is formed over the filling elements; and a protective layer which covers the recording elements and the filling elements and is in contact with an upper surface of the conductive film.Type: GrantFiled: February 13, 2006Date of Patent: March 23, 2010Assignee: TDK CorporationInventors: Kazuhiro Hattori, Takahiro Suwa
-
Patent number: 7682713Abstract: The magnetic recording medium includes: recording elements formed as the convex portions of the recording layer formed in the predetermined concavo-convex pattern over a substrate; and a filling elements with which a concave portions between the recording elements are filled. A surface concave portion is formed in a surface of the magnetic recording medium above the recording element. The surface concave portion has a cross-sectional shape of which a portion corresponding to a center of the recording element lying thereunder in a width direction thereof is recessed deepest toward the substrate, and has a width monotonically increasing with increase of a distance from the substrate.Type: GrantFiled: September 12, 2005Date of Patent: March 23, 2010Assignee: TDK CorporationInventors: Takahiro Suwa, Kazuhiro Hattori, Shuichi Okawa
-
Publication number: 20090310255Abstract: A highly reliable magnetic recording medium is provided which has a recording layer formed in a concavo-convex pattern and wherein the recording layer is unlikely to cause a change in magnetic properties. The magnetic recording medium includes a substrate, a recording layer formed in a predetermined concavo-convex pattern over the substrate, convex portions of the concavo-convex pattern serving as recording elements; and a filler portion filling a concave portion between the recording elements. The filler portion comprises a metal-based main filler material and oxygen. Oxygen is unevenly distributed in the filler portion so that the ratio of the number of oxygen atoms to the total of the number of atoms of the main filler material and the number of oxygen atoms is greater in an upper surface portion of the filler portion than in a lower portion of the filler portion.Type: ApplicationFiled: June 3, 2009Publication date: December 17, 2009Applicant: TDK CORPORATIONInventors: Shuichi Okawa, Kazuhiro Hattori, Narutoshi Fukuzawa, Takahiro Suwa
-
Patent number: 7616404Abstract: 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: GrantFiled: December 20, 2007Date of Patent: November 10, 2009Assignee: TDK CorporationInventors: Takahiro Suwa, Kazuya Shimakawa
-
Patent number: 7604880Abstract: 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: GrantFiled: March 22, 2005Date of Patent: October 20, 2009Assignee: TDK CorporationInventors: Mitsuru Takai, Yoshikazu Soeno, Katsumichi Tagami, Kazuya Shimakawa, Takahiro Suwa
-
Publication number: 20090242508Abstract: A filling material different from a first mask layer (temporary coating material) is deposited over a workpiece to fill concave portions. At least part of excess portions of the filling material is removed by a dry etching method such that at least part of the side surfaces of the first mask layer over recording elements are exposed. Then, the first mask layer is removed by a dry etching method which uses a reactive gas having the property of chemically reacting with and removing both the filling material and the first mask layer as a processing gas and in which an etching rate for the first mask layer is higher than that for the filling material, and the etching rate for the filling material is higher than that for a recording layer (a lower layer that is in contact with a lower surface of the first mask layer over recording elements).Type: ApplicationFiled: March 20, 2009Publication date: October 1, 2009Applicant: TDK CORPORATIONInventors: Kazuhiro Hattori, Shuichi Okawa, Narutoshi Fukuzawa, Takahiro Suwa
-
Publication number: 20090168244Abstract: The magnetic recording medium includes: a substrate; a recording layer formed in a predetermined concavo-convex pattern over the substrate, the concavo-convex pattern including a convex portion that serves as a recording element; and a filling portion that fills a concave portion between the recording elements. The filling portion comprises a metal-based main filling material and nitrogen. Nitrogen is unevenly distributed in the filling portion such that the ratio of the number of nitrogen atoms to the total number of atoms of the main filling material and nitrogen atoms is greater in the upper surface portion of the filling portion than in the lower portion thereof.Type: ApplicationFiled: December 19, 2008Publication date: July 2, 2009Applicant: TDK CORPORATIONInventors: Shuichi Okawa, Kazuhiro Hattori, Narutoshi Fukuzawa, Takahiro Suwa
-
Patent number: 7554768Abstract: On an information recording medium, a data track pattern and a servo pattern composed of a concave/convex pattern including a plurality of convex parts are formed on at least one surface of a substrate and respective concave parts in the concave/convex pattern are filled with non-magnetic material. In the concave/convex pattern that constructs the data track pattern, the respective convex parts are formed concentrically or in a spiral. In the concave/convex pattern that constructs the servo pattern, a unit convex part length along a direction of rotation of the substrate is set so that a value produced by dividing the unit convex part length by a distance from a center of the data track pattern decreases from an inner periphery to an outer periphery.Type: GrantFiled: August 31, 2005Date of Patent: June 30, 2009Assignee: TDK CorporationInventors: Yoshikazu Soeno, Takahiro Suwa
-
Patent number: 7538041Abstract: A magnetic recording medium is provided in which a magnetic recording layer 5 is provided in a predetermined concavo-convex pattern on a substrate 1A, a concave portion in a concavo-convex pattern is filled with a non-magnetic material, and a non-magnetic layer 16 formed of the non-magnetic material positioned at the bottom surface of the concave portion in the non-magnetic materials is formed on a convex portion of the concavo-convex pattern while surface of the convex portion and the concave portion is substantially flattened, and a thickness of the non-magnetic layer 16 is 1 nm or less.Type: GrantFiled: August 19, 2005Date of Patent: May 26, 2009Assignee: TDK CorporationInventors: Mitsuru Takai, Kazuhiro Hattori, Takahiro Suwa, Shuichi Okawa
-
Publication number: 20090101624Abstract: A method for efficiently manufacturing a magnetic recording medium by filling concave portions of a concavo-convex patterned recording layer with a filler to provide sufficient surface flatness is provided. A cladding is etched by a dry etching method in which an etch rate of the cladding is equal to or higher than an etch rate of the filler. Then, by dry etching method in which an etch rate of the filler is higher than that of the cladding, the filler is etched so that a top surface of a diaphragm over a recording element (or a top surface of the recording element in absence of the diaphragm) is exposed, and the cladding remains over the concave portion of the concavo-convex pattern of the recording layer.Type: ApplicationFiled: October 16, 2008Publication date: April 23, 2009Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Narutoshi Fukuzawa, Kazuhiro Hattori, Shuichi Okawa
-
Publication number: 20090067092Abstract: The magnetic recording medium includes: a recording layer formed over a substrate in a predetermined concavo-convex pattern, convex portions of the concavo-convex pattern constituting recording elements; a filler underlayer film formed on the bottoms of concave portions of the concavo-convex pattern; and a DLC filler formed on the filler underlayer film in contact with the filler underlayer film so as to fill the concave portions. The filler underlayer film is made of a material selected from the group consisting of a Si-containing material, a Ge-containing material, and a carbide material containing one or more metal elements selected from Ti, Ta, Nb, Mo, Zr, Cr, W, V, and Hf.Type: ApplicationFiled: September 3, 2008Publication date: March 12, 2009Applicant: TDK CORPORATIONInventors: Takahiro Suwa, Kazuya Shimakawa
-
Patent number: 7494727Abstract: 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: GrantFiled: July 25, 2005Date of Patent: February 24, 2009Assignee: TDK CorporationInventors: Takahiro Suwa, Kazuya Shimakawa
-
Publication number: 20090034115Abstract: A servo pattern is formed in a servo pattern region on at least one surface of a substrate of a magnetic recording medium by a concave/convex pattern including a plurality of convex parts, at least protruding end parts of which are formed of magnetic material, and at least one concave part. The servo pattern region includes an address pattern region and a burst pattern region. The at least one concave 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 protruding end surfaces of the convex parts formed in the address pattern region and an inscribed circle with a largest diameter out of inscribed circles on protruding end surfaces of the convex parts formed in the burst pattern region is an inscribed circle with a largest diameter out of inscribed circles on protruding end surfaces of the convex parts formed in the servo pattern region.Type: ApplicationFiled: October 10, 2008Publication date: February 5, 2009Applicant: TDK CorporationInventors: Yoshikazu SOENO, Takahiro SUWA