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).

  • Publication number: 20110097604
    Abstract: 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: Application
    Filed: March 30, 2009
    Publication date: April 28, 2011
    Applicant: WD MEDIA (SINGAPORE) PTE. LTD.
    Inventor: Takahiro Onoue
  • Publication number: 20110097600
    Abstract: 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: Application
    Filed: March 26, 2009
    Publication date: April 28, 2011
    Applicant: WD MEDIA (SINGAPORE) PTE. LTD.
    Inventor: Takahiro Onoue
  • Publication number: 20110097603
    Abstract: 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: Application
    Filed: March 26, 2009
    Publication date: April 28, 2011
    Applicant: WD MEDIA (SINGAPORE) PTE. LTD.
    Inventor: Takahiro Onoue
  • Publication number: 20100323220
    Abstract: 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: Application
    Filed: October 6, 2008
    Publication date: December 23, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventor: Takahiro Onoue
  • Publication number: 20100279151
    Abstract: 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: Application
    Filed: October 14, 2008
    Publication date: November 4, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventors: Kazuaki Sakamoto, Kong Kim, Takahiro Onoue, Masafumi Ishiyama, Teiichiro Umezawa, Kenji Ayama
  • Publication number: 20100255348
    Abstract: 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: Application
    Filed: March 31, 2010
    Publication date: October 7, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventors: Tokichiro SATO, Takahiro ONOUE, Takenori KAJIWARA
  • Publication number: 20100247965
    Abstract: 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: Application
    Filed: March 31, 2010
    Publication date: September 30, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventor: Takahiro Onoue
  • Publication number: 20100247964
    Abstract: 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: Application
    Filed: March 30, 2010
    Publication date: September 30, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventors: Takahiro ONOUE, Tokichiro Sato, Takenori Kajiwara
  • Publication number: 20100039724
    Abstract: 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: Application
    Filed: September 26, 2007
    Publication date: February 18, 2010
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventors: Takahiro Onoue, Akira Shimada
  • Publication number: 20100021768
    Abstract: [PROBLEMS] To improve the track density by reducing the track edge noise and sharpening the boundaries of a recording magnetic field by blocking the recording magnetic field spreading outside the recording region in magnetic recording. [MEANS FOR SOLVING PROBLEMS] 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).
    Type: Application
    Filed: February 13, 2008
    Publication date: January 28, 2010
    Inventors: Yoshiaki Sonobe, Takahiro Onoue, Koichi Wago
  • Publication number: 20090311557
    Abstract: [Object] To achieve a high coercive force (Hc) and low-noise characteristics (high S/N ratio) through realization of both segregation of SiO2 and high perpendicular magnetic anisotropy by providing a two-layer structure having magnetic recording layers with different properties. [Solution] A magnetic disk for use in perpendicular magnetic recording, having at least an underlayer 5, a first magnetic recording layer 6, and a second magnetic recording layer 7 on a substrate in this order. The first magnetic recording layer 6 and the second magnetic recording layer 7 are each a ferromagnetic layer of a granular structure containing a nonmagnetic substance forming grain boundary portions between crystal grains containing at least Co (cobalt). Given that the content of the nonmagnetic substance in the first magnetic recording layer 6 is A mol % and the content of the nonmagnetic substance in the second magnetic recording layer 7 is B mol %, A>B.
    Type: Application
    Filed: March 31, 2007
    Publication date: December 17, 2009
    Inventors: Takahiro Onoue, Kong Kim, Yoshiaki Sonobe, Chikara Takasu
  • Publication number: 20090191331
    Abstract: [Object] To provide a manufacturing method that can easily enhance a reversed domain nucleation magnetic field of a magnetic recording layer in a perpendicular magnetic recording medium having, over a substrate, a soft magnetic layer, the magnetic recording layer having a granular structure, and a continuous layer having a high perpendicular magnetic anisotropy.
    Type: Application
    Filed: March 31, 2007
    Publication date: July 30, 2009
    Applicants: Hoya Corporation, Hoya Magnetics Singapore PTE. LTD.
    Inventors: Teiichiro Umezawa, Takahiro Onoue, Chikara Takasu, Kong Kim
  • Publication number: 20090117408
    Abstract: To provide a perpendicular magnetic recording disk having a film structure that improves overwrite characteristics (O/W) while maintaining a coercive force (Hc) high enough not to affect heat fluctuation resistance, and a manufacturing method thereof. A magnetic disk for use in perpendicular magnetic recording, having at least an underlayer, a first magnetic recording layer, and a second magnetic recording layer on a substrate in the order named, characterized in that the first magnetic recording layer and the second magnetic recording layer are each a ferromagnetic layer of a granular structure containing a nonmagnetic substance forming grain boundary portions between crystal grains containing at least Co (cobalt) and, given that the content of the nonmagnetic substance in the first magnetic recording layer is A mol % and the content of the nonmagnetic substance in the second magnetic recording layer is B mol %, A<B.
    Type: Application
    Filed: March 31, 2007
    Publication date: May 7, 2009
    Applicants: HOYA CORPORATION, HOYA MAGNETICS SINGAPORE PTE. LTD.
    Inventors: Teiichiro Umezawa, Lianjun Wu, Yoshiaki Sonobe, Chikara Takasu, Takahiro Onoue