Patents by Inventor Takahiro Onoue
Takahiro Onoue 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: 8603649Abstract: A perpendicular magnetic recording medium includes a magnetic recording layer 22 having a granular structure composed of crystal grains containing cobalt (Co) and grown in a columnar shape and a grain boundary portion comprising a nonmagnetic substance and formed between the crystal grains, and a continuous layer 24 of a thin film magnetically continuous in a film plane direction. The continuous layer 24 includes a plurality of layers 24a and 24b containing cobalt, chromium (Cr), and platinum (Pt). Among the layers, the layer 24a nearer to the magnetic recording layer has a greater chromium content.Type: GrantFiled: October 6, 2008Date of Patent: December 10, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Takahiro Onoue
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Patent number: 8592061Abstract: In order to provide a magnetic recording medium having excellent electromagnetic conversion characteristics, a magnetic recording medium (10) is provided with a substrate (12), and a magnetic recording layer (20) formed on the substrate (12). The magnetic recording layer (20) is provided with a granular layer (32), i.e., a magnetic layer, including magnetic grains and a nonmagnetic material surrounding the magnetic grains in a section parallel to the main surface of the substrate. The ratio of the long diameter to the short diameter of each magnetic grain contained in the granular layer (32) is calculated in the section. In the histogram of such ratio, a half width at half maximum of the histogram is 0.6 or less and the variance of grain diameters of the magnetic grains in the section is 20% or less of the average grain diameter of the magnetic grains.Type: GrantFiled: September 26, 2007Date of Patent: November 26, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Takahiro Onoue, Akira Shimada
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Patent number: 8580410Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, the medium in which a particle diameter of crystal grains in the magnetic recording layer 122 of a two-layer structure is so designed as to improve an SNR while a high coercive force is maintained.Type: GrantFiled: March 26, 2009Date of Patent: November 12, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventor: Takahiro Onoue
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Publication number: 20130230647Abstract: A perpendicular magnetic recording medium comprises a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a non-magnetic layer formed of a non-magnetic material below the underlayer to control crystal orientation of the underlayer, a soft magnetic layer provided below the non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the non-magnetic layer, and the soft magnetic layer are formed. The non-magnetic layer comprises a first non-magnetic layer formed above the soft magnetic layer and a second non-magnetic layer formed above the first non-magnetic layer. The first non-magnetic layer is formed of amorphous Ni compound while the second non-magnetic layer is formed of crystalline Ni or crystalline Ni compound.Type: ApplicationFiled: April 23, 2013Publication date: September 5, 2013Applicant: WD Media (Singapore) PTE.LTD.Inventors: Takahiro ONOUE, Tokichiro Sato, Takenori Kajiwara
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Patent number: 8431258Abstract: A perpendicular magnetic recording medium comprises a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a non-magnetic layer formed of a non-magnetic material below the underlayer to control crystal orientation of the underlayer, a soft magnetic layer provided below the non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the non-magnetic layer, and the soft magnetic layer are formed. The non-magnetic layer comprises a first non-magnetic layer formed above the soft magnetic layer and a second non-magnetic layer formed above the first non-magnetic layer. The first non-magnetic layer is formed of amorphous Ni compound while the second non-magnetic layer is formed of crystalline Ni or crystalline Ni compound.Type: GrantFiled: March 30, 2010Date of Patent: April 30, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Takahiro Onoue, Tokichiro Sato, Takenori Kajiwara
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Patent number: 8404370Abstract: A perpendicular magnetic recording medium 100 has, over a substrate, at least a magnetic recording layer 122 with a granular structure in which nonmagnetic grain boundaries are formed between magnetic grains continuously grown into a columnar shape. The magnetic grains of the magnetic recording layer 122 contain Co, Cr, and Pt. The magnetic recording layer 122 contains at least one oxide selected from a group A including SiO2, TiO2, and Cr2O3, at least one oxide selected from a group B consisting of oxides each having a larger Gibbs free energy ?G than the group A, and a reducing agent adapted to reduce the oxides of the group B.Type: GrantFiled: March 31, 2010Date of Patent: March 26, 2013Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Tokichiro Sato, Takahiro Onoue, Takenori Kajiwara
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Patent number: 8076013Abstract: A magnetic recording medium (10) has a substrate (12) and a perpendicular magnetic recording layer (30) formed over the substrate (12). The perpendicular magnetic recording layer (30) has a granular layer (20) in which a magnetic signal is recorded and a continuous film layer (24) magnetically coupled to the granular layer (20). The continuous film layer (24) has hard magnetic portions (204) formed in positions corresponding to the recording regions where magnetic signals are recorded in the granular layer (20) and magnetic shield portions (202) formed between the hard magnetic portions (204), each having a magnetization curve whose slope is larger than those of the hard magnetic portions in the region where the applied magnetic filed is zero when the magnetization curve is measured, and each having a residual magnetic polarization smaller than those in the hard magnetic portions.Type: GrantFiled: February 13, 2008Date of Patent: December 13, 2011Assignee: WD Media (Singapore) Pte. Ltd.Inventors: Yoshiaki Sonobe, Takahiro Onoue, Koichi Wago
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Publication number: 20110223446Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is further improved while a high coercive force Hc is secured so that a higher recoding density can be achieved.Type: ApplicationFiled: September 16, 2009Publication date: September 15, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Takahiro Onoue, Teiichiro Umezawa
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Publication number: 20110212346Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium the SNR of which is improved by reducing noise thought to be due to an auxiliary recording layer so that a higher recording density can be achieved, and a method of manufacturing the same. In order to achieve the above object, a representative configuration of a perpendicular magnetic recording medium 100 according to the present invention includes, on a base, at least a magnetic recording layer 122 having a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape; a non-magnetic split layer 124 disposed on the magnetic recording layer 122 and containing Ru and oxygen; and an auxiliary recording layer 126 that is disposed on the split layer 124 and that is magnetically approximately continuous in an in-plane direction of a main surface of the base 110.Type: ApplicationFiled: September 16, 2009Publication date: September 1, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Takahiro Onoue, Teiichiro Umezawa, Toshiaki Tachibana, Masafumi Ishiyama
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Publication number: 20110206947Abstract: By improving sliding durability while ensuring a high SNR, an improvement in reliability and a further increase in recording density are to be achieved.Type: ApplicationFiled: December 28, 2010Publication date: August 25, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Toshiaki TACHIBANA, Takahiro Onoue, Keiichi Kajita
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Publication number: 20110171495Abstract: An object is to provide a perpendicular magnetic recording medium including a ground layer that prevents corrosion, while achieving a primary object of promoting finer magnetic particles of a magnetic recording layer and isolation of these magnetic particles. The structure of a perpendicular magnetic recording medium 100 according to the present invention includes, at least on a base 110: a magnetic recording layer 122 on which a signal is recorded; a ground layer 118 provided below the magnetic recording layer; a non-magnetic layer 116 for controlling crystal orientation of the ground layer; and a soft magnetic layer 114 provided below the non-magnetic layer. The ground layer 118 is configured to have three layers including, in an order from bottom, a first ground layer 118a and a second ground layer 118b that contain ruthenium, and a third ground layer 118c that contains a metal.Type: ApplicationFiled: January 10, 2011Publication date: July 14, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventors: Toshiaki TACHIBANA, Takahiro ONOUE
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Publication number: 20110111262Abstract: An object of the present invention is to provide a method of manufacturing a perpendicular magnetic recording medium (100) in which both of a coercive force Hc and reliability can be achieved at a higher level even with heating at the time of forming a medium protective layer (126) and to provide the perpendicular magnetic recording medium (100).Type: ApplicationFiled: March 25, 2009Publication date: May 12, 2011Applicant: WD Media (Singapore) Pte. Ltd.Inventors: Teiichiro Umezawa, Masafumi Ishiyama, Tokichiro Sato, Kenji Ayama, Takahiro Onoue, Junichi Horikawa
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Publication number: 20110097603Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium in which each space between crystal grains of a first magnetic recording layer is so designed as to allow the layer to also have a function as a continuous layer, and a method of manufacturing a perpendicular magnetic recording medium. In a perpendicular magnetic recording medium 100 according to the present invention, a first magnetic recording layer 122a and a second magnetic recording layer 122b are ferromagnetic layers each having a granular structure in which a grain boundary part made of a non-magnetic substance is formed between crystal grains each grown in a column shape and, in the first magnetic recording layer 122a, an intergranular distance defined by an average of shortest distances between grain boundary parts each between a crystal grain and its adjacent crystal grain is equal to or shorter than 1 nm.Type: ApplicationFiled: March 26, 2009Publication date: April 28, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventor: Takahiro Onoue
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Publication number: 20110097604Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium capable of reducing noise in an electromagnetic transducing characteristic in a configuration including a magnetic recording layer of a granular structure containing Co and an auxiliary recording layer. The perpendicular magnetic recording medium of the present invention includes: on a non-magnetic substrate, a first magnetic recording layer 20a of a granular structure in which a non-magnetic grain boundary part is provided between magnetic grains in a columnar shape containing at least Co; a non-magnetic layer 22 provided on the first magnetic recording layer 20a; a second magnetic recording layer 20b of a granular structure in which a non-magnetic grain boundary part is provided between magnetic grains in a columnar shape containing Co provided on the non-magnetic layer 22; and an auxiliary recording layer 24 provided on the second magnetic recording layer 20b.Type: ApplicationFiled: March 30, 2009Publication date: April 28, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventor: Takahiro Onoue
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Publication number: 20110097600Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, the medium in which a particle diameter of crystal grains in the magnetic recording layer 122 of a two-layer structure is so designed as to improve an SNR while a high coercive force is maintained.Type: ApplicationFiled: March 26, 2009Publication date: April 28, 2011Applicant: WD MEDIA (SINGAPORE) PTE. LTD.Inventor: Takahiro Onoue
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Publication number: 20100323220Abstract: A perpendicular magnetic recording medium includes a magnetic recording layer 22 having a granular structure composed of crystal grains containing cobalt (Co) and grown in a columnar shape and a grain boundary portion comprising a nonmagnetic substance and formed between the crystal grains, and a continuous layer 24 of a thin film magnetically continuous in a film plane direction. The continuous layer 24 includes a plurality of layers 24a and 24b containing cobalt, chromium (Cr), and platinum (Pt). Among the layers, the layer 24a nearer to the magnetic recording layer has a greater chromium content.Type: ApplicationFiled: October 6, 2008Publication date: December 23, 2010Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.Inventor: Takahiro Onoue
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Publication number: 20100279151Abstract: A perpendicular magnetic recording medium includes a substrate, a soft magnetic layer, a pre-underlayer, an underlayer, and a main recording layer serving as a magnetic recording layer. The pre-underlayer contains seed crystal grains that serve as a base for crystal grains of the underlayer, and an addition substance that is added between the seed crystal grains and composed of an element having an atomic radius smaller than that of an element forming the seed crystal grains.Type: ApplicationFiled: October 14, 2008Publication date: November 4, 2010Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.Inventors: Kazuaki Sakamoto, Kong Kim, Takahiro Onoue, Masafumi Ishiyama, Teiichiro Umezawa, Kenji Ayama
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Publication number: 20100255348Abstract: A perpendicular magnetic recording medium 100 has, over a substrate, at least a magnetic recording layer 122 with a granular structure in which nonmagnetic grain boundaries are formed between magnetic grains continuously grown into a columnar shape. The magnetic grains of the magnetic recording layer 122 contain Co, Cr, and Pt. The magnetic recording layer 122 contains at least one oxide selected from a group A including SiO2, TiO2, and Cr2O3, at least one oxide selected from a group B consisting of oxides each having a larger Gibbs free energy ?G than the group A, and a reducing agent adapted to reduce the oxides of the group B.Type: ApplicationFiled: March 31, 2010Publication date: October 7, 2010Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.Inventors: Tokichiro SATO, Takahiro ONOUE, Takenori KAJIWARA
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Publication number: 20100247964Abstract: A perpendicular magnetic recording medium comprises a magnetic recording layer that records a signal, an underlayer formed of Ru or Ru compound below the magnetic recording layer, a non-magnetic layer formed of a non-magnetic material below the underlayer to control crystal orientation of the underlayer, a soft magnetic layer provided below the non-magnetic layer, and a substrate on which the magnetic recording layer, the underlayer, the non-magnetic layer, and the soft magnetic layer are formed. The non-magnetic layer comprises a first non-magnetic layer formed above the soft magnetic layer and a second non-magnetic layer formed above the first non-magnetic layer. The first non-magnetic layer is formed of amorphous Ni compound while the second non-magnetic layer is formed of crystalline Ni or crystalline Ni compound.Type: ApplicationFiled: March 30, 2010Publication date: September 30, 2010Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.Inventors: Takahiro ONOUE, Tokichiro Sato, Takenori Kajiwara
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Publication number: 20100247965Abstract: In a perpendicular magnetic recording medium having, over a substrate, a magnetic recording layer, an underlayer made of Ru or a Ru compound and provided below the magnetic recording layer, a pre-underlayer made of a nonmagnetic crystalline material, and a soft magnetic layer provided below the pre-underlayer, when the difference between the highest point and the lowest point of unevenness of the interface between the soft magnetic layer and the pre-underlayer, derived by a cross-sectional TEM image, is given as an interface roughness (nm) and the distance between the soft magnetic layer and the magnetic recording layer, excluding the soft magnetic layer and the magnetic recording layer, is given as a SUL-MAG distance (nm), interface roughness (nm)?0.4 (nm) and interface roughness×SUL-MAG distance (nm)?12 (nm) are satisfied.Type: ApplicationFiled: March 31, 2010Publication date: September 30, 2010Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.Inventor: Takahiro Onoue