Patents by Inventor Teiichiro Umezawa

Teiichiro Umezawa 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).

  • Patent number: 9946153
    Abstract: Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.
    Type: Grant
    Filed: September 19, 2016
    Date of Patent: April 17, 2018
    Assignee: HOYA CORPORATION
    Inventors: Teiichiro Umezawa, Masafumi Ishiyama
  • Publication number: 20170003583
    Abstract: Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.
    Type: Application
    Filed: September 19, 2016
    Publication date: January 5, 2017
    Applicant: HOYA CORPORATION
    Inventors: Teiichiro UMEZAWA, Masafumi Ishiyama
  • Patent number: 9470971
    Abstract: Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.
    Type: Grant
    Filed: May 9, 2013
    Date of Patent: October 18, 2016
    Assignee: HOYA CORPORATION
    Inventors: Teiichiro Umezawa, Masafumi Ishiyama
  • Patent number: 9349404
    Abstract: [Problem] A perpendicular magnetic disk with an improved SNR and an increased recording density by further improving crystal orientation of a preliminary ground layer formed of an Ni-base alloy is provided. [Solution] A typical structure of the perpendicular magnetic disk according to the present invention includes, on a base 110, a soft magnetic layer 130, a Ta alloy layer 140 provided on the soft magnetic layer 130, an Ni alloy layer 142 provided on the Ta alloy layer 140, a ground layer 150 provided on the Ni alloy layer 142 and having Ru as a main component, and a granular magnetic layer 160 provided on the ground layer 150. The Ta alloy layer 140 is a layer containing 10 atomic percent or more and 45 atomic percent or less Ta and having amorphous and soft magnetic properties.
    Type: Grant
    Filed: May 31, 2011
    Date of Patent: May 24, 2016
    Assignee: WD Media (Singapore) PTE. LTD
    Inventors: Teiichiro Umezawa, Kazuaki Sakamoto
  • Patent number: 9240204
    Abstract: A perpendicular magnetic disk is provided. The disk includes, on a base and in the order from bottom, a first granular magnetic layer group including a plurality of magnetic layers each having a granular structure, a non-magnetic layer having Ru or a Ru alloy as a main component, a second granular magnetic layer group including a plurality of magnetic layers each having the granular structure, and an auxiliary recording layer having a CoCrPtRu alloy as a main component. Layers closer to a front surface among the plurality of magnetic layers included in the first granular magnetic layer group having an equal or smaller content of Pt. Layers closer to the front surface among the plurality of magnetic layers included in the second granular magnetic layer group having an equal or smaller content of Pt and having an equal or larger content of an oxide.
    Type: Grant
    Filed: May 20, 2011
    Date of Patent: January 19, 2016
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Teiichiro Umezawa, Takenori Kajiwara, Tokichiro Sato
  • Patent number: 9159351
    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: Grant
    Filed: October 14, 2008
    Date of Patent: October 13, 2015
    Assignee: WD Media (Singapore) PTE. LTD
    Inventors: Kazuaki Sakamoto, Kong Kim, Takahiro Onoue, Masafumi Ishiyama, Teiichiro Umezawa, Kenji Ayama
  • Publication number: 20150262602
    Abstract: Embodiments of a perpendicular magnetic recording medium include: a base; at least a first magnetic recording layer 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 containing Ru disposed on the first magnetic layer; and a second magnetic recording layer that is disposed on the split layer and that has a granular structure in which a non-magnetic grain boundary portion is formed between crystal particles grown in a columnar shape, wherein the first magnetic layer and the second magnetic layer contain oxides that form the grain boundary, and when an oxide content of the first magnetic layer is represented by A and an oxide content of the second magnetic layer is represented by B, a relationship between the oxide contents A/B is in the range of 0.5<A/B<1.0.
    Type: Application
    Filed: May 28, 2015
    Publication date: September 17, 2015
    Inventors: TAKAHIRO ONOUE, TEIICHIRO UMEZAWA
  • Patent number: 9064518
    Abstract: 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: Grant
    Filed: September 16, 2009
    Date of Patent: June 23, 2015
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Takahiro Onoue, Teiichiro Umezawa
  • Publication number: 20150104735
    Abstract: Provided is a mask blank in which a thin film for transfer pattern formation is provided on a main surface of a transparent substrate. The thin film is made of a material containing a transition metal and silicon and further containing at least one of oxygen and nitrogen. The thin film has as its surface layer an oxide layer with an oxygen content higher than that of the thin film of a region other than the surface layer. The thin film is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side. The oxide layer is formed so that the thickness of its outer peripheral portion is greater than that of its central portion on the main surface side.
    Type: Application
    Filed: May 9, 2013
    Publication date: April 16, 2015
    Applicant: HOYA CORPORATION
    Inventors: Teiichiro Umezawa, Masafumi Ishiyama
  • Patent number: 9005699
    Abstract: A method for manufacturing a magnetic recording medium includes the steps of (a) forming a perpendicular magnetic recording layer and (b) applying an ion beam to regions between tracks of the perpendicular magnetic recording layer so as to form separation regions for magnetically separating the tracks from each other. In the step (a), a continuous film layer composed of a multilayer film is formed, and CoB layers and Pd layers are laminated in the multilayer film. In the step (b), the CoB layers and the Pd layers are melted by the ion beam so as to form an alloy of metals contained in the CoB layers and the Pd layers to thereby form the separation regions.
    Type: Grant
    Filed: September 27, 2007
    Date of Patent: April 14, 2015
    Assignee: WD Media, LLC
    Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Koichi Wago
  • Patent number: 8871368
    Abstract: A perpendicular magnetic recording medium with SNR improved by reducing noise due to an auxiliary recording layer so that a higher recording density can be achieved. The perpendicular magnetic recording medium 100 includes 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: Grant
    Filed: September 16, 2009
    Date of Patent: October 28, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Takahiro Onoue, Teiichiro Umezawa, Toshiaki Tachibana, Masafumi Ishiyama
  • Patent number: 8795857
    Abstract: A perpendicular magnetic recording medium of the invention is characterized by having, on a disk substrate 110, a soft magnetic layer 14, a magnetic recording layer 22, a continuous layer 24 magnetically continuous in the in-plane direction of the substrate, a blocking layer 25 for blocking shock imposed on the continuous layer, and a medium protective layer 28 containing carbon formed on the blocking layer.
    Type: Grant
    Filed: September 24, 2008
    Date of Patent: August 5, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Kenji Ayama, Tokichiro Sato, Teiichiro Umezawa, Masafumi Ishiyama
  • Patent number: 8697261
    Abstract: An object of the present invention is to increase an electromagnetic transducing characteristic (in particular, SNR) by further promoting separation and isolation of magnetic grains of a magnetic recording layer (122) in a perpendicular magnetic recording medium (100).
    Type: Grant
    Filed: March 25, 2009
    Date of Patent: April 15, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Teiichiro Umezawa
  • Patent number: 8623528
    Abstract: 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: Grant
    Filed: March 25, 2009
    Date of Patent: January 7, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Teiichiro Umezawa, Masafumi Ishiyama, Tokichiro Sato, Kenji Ayama, Takahiro Onoue, Junichi Horikawa
  • Patent number: 8603650
    Abstract: A magnetic disk 10 for use in perpendicular magnetic recording has at least a magnetic recording layer on a substrate 1. The magnetic recording layer is composed of a ferromagnetic layer 5 of a granular structure containing silicon (Si) or an oxide of silicon (Si) between crystal grains containing cobalt (Co), a stacked layer 7 having a first layer containing cobalt (Co) or a Co alloy and a second layer containing palladium (Pd) or platinum (Pt), and a spacer layer 6 interposed between the ferromagnetic layer 5 and the stacked layer 7. After forming the ferromagnetic layer 5 on the substrate 1 by sputtering in an argon gas atmosphere, the stacked layer 7 is formed by sputtering in the argon gas atmosphere at a gas pressure lower than that used when forming the ferromagnetic layer 5.
    Type: Grant
    Filed: June 29, 2005
    Date of Patent: December 10, 2013
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Chikara Takasu
  • Patent number: 8546000
    Abstract: A perpendicular magnetic disk that includes, a base 110, a granular magnetic layer 160, and a auxiliary recording layer 180 disposed as an upper layer of the granular magnetic layer 160. The granular magnetic layer 160 has a granular structure in which a grain boundary portion is formed by segregation of a non-magnetic substance containing an oxide as a main component around magnetic particles containing a CoCrPt alloy grown in a columnar shape as a main component. The auxiliary recording layer 180 contains a CoCrPtRu alloy as a main component and has a film thickness of 1.5 nm to 4.0 nm. With this structure, the auxiliary recording layer can be thinned while maintaining the function thereof to improve SNR.
    Type: Grant
    Filed: April 28, 2011
    Date of Patent: October 1, 2013
    Assignee: WD Media, LLC
    Inventor: Teiichiro Umezawa
  • Patent number: 8367228
    Abstract: A method for manufacturing a magnetic recording medium for perpendicular magnetic recording includes the steps of forming a first magnetic layer which has magnetic crystal grains exhibiting perpendicular magnetic anisotropy and nonmagnetic substances for magnetically separating the magnetic crystal grains from each other at grain boundaries of the magnetic crystal grains, forming a second magnetic layer which has magnetic grains exchange-coupled to the magnetic crystal grains, a grain boundary width of the magnetic grains being smaller than a grain boundary width of the magnetic crystal grains, and forming separation regions which magnetically separate tracks from each other in regions between the tracks of the magnetic recording medium in at least the second magnetic layer. The separation regions are disposed substantially only in the second magnetic layer of the first magnetic layer and the second magnetic layer.
    Type: Grant
    Filed: October 18, 2010
    Date of Patent: February 5, 2013
    Assignee: WD Media (Singapore) PTE. Ltd.
    Inventors: Yoshiaki Sonobe, Teiichiro Umezawa, Koichi Wago
  • Patent number: 8309239
    Abstract: A vertical magnetic recording disc (100) includes a base (10), a magnetic recording layer (22), and a medium protection layer (26). The magnetic recording layer (22) is a ferromagnetic layer having a granular structure where a granular portion is formed. The medium protection layer (26) contains nitrogen (N) atoms and carbon (C) atoms with a number ratio (N/C) in a range from 0.050 to 0.150. In a Raman spectrum obtained by exciting the medium protection layer (26) by argon ion laser light of wavelength 514.5 nm, from which a fluorescence is removed, the peak ratio Dh/Gh is in a range from 0.70 to 0.95, when a D peak Dh appearing in the vicinity of 1350 cm?1 is separated from G peak Gh appearing in the vicinity of 1520 cm?1 by the Gauss function.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: November 13, 2012
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventors: Teiichiro Umezawa, Masafumi Ishiyama, Kenji Ayama, Tokichiro Sato
  • Publication number: 20120189872
    Abstract: A perpendicular magnetic disk is provided. The disk includes, on a base and in the order from bottom, a first granular magnetic layer group including a plurality of magnetic layers each having a granular structure, a non-magnetic layer having Ru or a Ru alloy as a main component, a second granular magnetic layer group including a plurality of magnetic layers each having the granular structure, and an auxiliary recording layer having a CoCrPtRu alloy as a main component. Layers closer to a front surface among the plurality of magnetic layers included in the first granular magnetic layer group having an equal or smaller content of Pt. Layers closer to the front surface among the plurality of magnetic layers included in the second granular magnetic layer group having an equal or smaller content of Pt and having an equal or larger content of an oxide.
    Type: Application
    Filed: May 20, 2011
    Publication date: July 26, 2012
    Applicant: WD MEDIA (SINGAPORE) PTE. LTD.
    Inventors: Teiichiro Umezawa, Takenori Kajiwara, Tokichiro Sato
  • Publication number: 20120141833
    Abstract: [Problem] A perpendicular magnetic disk with an improved SNR and an increased recording density by further improving crystal orientation of a preliminary ground layer formed of an Ni-base alloy is provided. [Solution] A typical structure of the perpendicular magnetic disk according to the present invention includes, on a base 110, a soft magnetic layer 130, a Ta alloy layer 140 provided on the soft magnetic layer 130, an Ni alloy layer 142 provided on the Ta alloy layer 140, a ground layer 150 provided on the Ni alloy layer 142 and having Ru as a main component, and a granular magnetic layer 160 provided on the ground layer 150. The Ta alloy layer 140 is a layer containing 10 atomic percent or more and 45 atomic percent or less Ta and having amorphous and soft magnetic properties.
    Type: Application
    Filed: May 31, 2011
    Publication date: June 7, 2012
    Applicant: WD MEDIA (SINGAPORE) PTE. LTD.
    Inventors: TEIICHIRO UMEZAWA, KAZUAKI SAKAMOTO