Patents by Inventor Takashi Hikosaka

Takashi Hikosaka 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: 20090116142
    Abstract: In a disk device, an arm for supporting a head includes upper and lower plates that are located parallel to a surface of a magnetic disk. The lower plate has a linear expansion coefficient greater than that of the upper plate. The upper and lower plates are provided with an electrically-heated wire. When a present altitude of the disk device exceeds a threshold altitude, an electric current is supplied to the heated wire so that the upper and lower plates are expanded. Due to a difference in the linear expansion coefficients between the upper and lower plates, the arm is warped in a direction away from the magnetic disk so that a distance between the head and the surface of the magnetic disk is increased.
    Type: Application
    Filed: October 21, 2008
    Publication date: May 7, 2009
    Applicant: DENSO CORPORATION
    Inventor: Takashi Hikosaka
  • Publication number: 20080057348
    Abstract: A soft magnetic undercoat film, a first undercoat film, a second undercoat film, a perpendicular magnetic recording film, and a protective film are provided on a non-magnetic substrate, and the first undercoat film consists of Pt, Pd, or an alloy including at least one among these, and the second undercoat film consists of Ru or an Ru alloy.
    Type: Application
    Filed: January 14, 2004
    Publication date: March 6, 2008
    Inventors: Kenji Shimizu, Akira Sakawaki, Kazuo Kobayashi, Nguyen Tien Duong, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa, Tomoyuki Maeda, Futoshi Nakamura
  • Patent number: 7289298
    Abstract: Disclosed is a magnetic recording medium which includes a substrate, an underlayer, and a perpendicular magnetic recording layer, and in which this perpendicular magnetic recording layer contains magnetic crystal grains and a matrix surrounding the magnetic crystal grains, and the matrix contains an element selected from Zn, Cd, Al, Ga, and In, and a component selected from P, As, Sb, S, Se, and Te.
    Type: Grant
    Filed: March 8, 2004
    Date of Patent: October 30, 2007
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Tomoyuki Maeda, Takashi Hikosaka, Futoshi Nakamura, Takeshi Iwasaki, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 7252896
    Abstract: An orientation control layer having a granular structure is formed between a substrate and magnetic recording layer, contains a base material and grains dispersed in the base material, and having a thickness smaller than a grain size of the grains.
    Type: Grant
    Filed: February 27, 2004
    Date of Patent: August 7, 2007
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Futoshi Nakamura, Takashi Hikosaka, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Publication number: 20070111035
    Abstract: The present invention aims to provide a magnetic recording medium, a method for producing the same, and a magnetic recording and reproducing device which can prevent spike noise and improve the error rate. The present invention provides a magnetic recording medium, a method for producing the same, and a magnetic recording and reproducing device comprising at least one nonmagnetic substrate, a soft magnetic underlayer 2, an orientation control layer to control the orientation of the layer formed directly above the same, and a perpendicular magnetic layer having an axis of easy magnetization which is oriented mainly perpendicularly to the nonmagnetic substrate, and the soft magnetic underlayer 2 is formed with a multilayer structure having soft magnetic layers 21A and 21B, and one or more separation layers 22 interposed between the soft magnetic layers, and at least one of the soft magnetic layers 21A and 21B comprises a material with a structure having no magnetic domain walls.
    Type: Application
    Filed: November 9, 2006
    Publication date: May 17, 2007
    Inventors: Kenji Shimizu, Hiroshi Sakai, Takashi Hikosaka, Futoshi Nakamura
  • Patent number: 7166375
    Abstract: A magnetic recording medium, a method for producing the same, and a magnetic recording and reproducing device are provided which can prevent spike noise and improve the error rate. The magnetic recording medium comprises at least one nonmagnetic substrate, a soft magnetic underlayer, an orientation control layer to control the orientation of the layer formed directly above the same, and a perpendicular magnetic layer having an axis of easy magnetization which is oriented mainly perpendicularly to the nonmagnetic substrate. The soft magnetic underlayer is formed with a multilayer structure having at least two soft magnetic layers and one or more separation layers interposed between the soft magnetic layers, and at least one of the soft magnetic layers comprises a material with a structure having no magnetic domain walls.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: January 23, 2007
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Hiroshi Sakai, Takashi Hikosaka, Futoshi Nakamura
  • Patent number: 7166376
    Abstract: A multi-layer including a magnetic recording layer and a high-magnetostriction layer having a magnetostriction constant larger than that of the magnetic recording layer is formed.
    Type: Grant
    Filed: February 26, 2004
    Date of Patent: January 23, 2007
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Takashi Hikosaka, Futoshi Nakamura, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 7141315
    Abstract: A magnetic recording medium includes a nonmagnetic substrate on which is provided at least a soft magnetic under-film, an orientation control film that controls an orientation of a film directly above, a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate and a protective film, wherein the orientation control film is alloy containing at least Cr and C. The magnetic recording medium is manufactured by a method including carrying out, in order, at least a step of forming a soft magnetic under-film on a nonmagnetic substrate, a step of forming an orientation control film that controls an orientation of a film directly above, a step of forming a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate, and a step of forming a protective film.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: November 28, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Futoshi Nakamura
  • Patent number: 7141316
    Abstract: Disclosed is a perpendicular magnetic recording medium in which an undercoating layer having crystal grains and a grain boundary material containing a carbide or boride is formed below a perpendicular magnetic recording layer, and another undercoating layer containing one of elements forming the crystal grains is formed below the aforementioned undercoating layer, and which can perform high?density recording by further decreasing the grain size of the perpendicular magnetic recording layer.
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: November 28, 2006
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K. K.
    Inventors: Takeshi Iwasaki, Takashi Hikosaka, Soichi Oikawa, Futoshi Nakamura, Tomoyuki Maeda, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 7138194
    Abstract: The magnetic recording medium comprises a soft magnetic undercoat film, an orientation control film that controls the orientation of a film provided directly above, a perpendicular magnetic film of which axis of easy magnetization is generally oriented perpendicular to a non-magnetic substrate, and a protective film, that are provided on the non-magnetic substrate, wherein the orientation control film is made of a Co alloy which contains one or more elements selected from Ti, V, Sr, Y, Nb, Mo, Hf, Ta, Ni and W.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: November 21, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 7132176
    Abstract: A perpendicular magnetic recording medium includes a magnetic recording layer stacked on a substrate and having a first perpendicular magnetic recording layer containing cobalt, and a second perpendicular magnetic recording layer mainly containing a crystalline alloy which contains a rare earth element and a transition metal.
    Type: Grant
    Filed: July 25, 2003
    Date of Patent: November 7, 2006
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Takeshi Iwasaki, Takashi Hikosaka, Soichi Oikawa, Futoshi Nakamura, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 7105239
    Abstract: In a magnetic recording medium, a longitudinal hard magnetic layer, interlayer, longitudinal soft magnetic layer, and magnetic recording layer are multilayered on a substrate. The interlayer is one of a magnetic layer having saturation magnetization smaller than that of the longitudinal hard magnetic layer, a nonmagnetic layer mainly containing cobalt or ruthenium or having a thickness of 0.5 nm or less, and an oxide layer of the longitudinal hard magnetic layer.
    Type: Grant
    Filed: September 5, 2002
    Date of Patent: September 12, 2006
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Soichi Oikawa, Takashi Hikosaka, Futoshi Nakamura, Takeshi Iwasaki, Hiroshi Sakai, Akira Sakawaki, Kenji Shimizu
  • Patent number: 7083870
    Abstract: A magnetic recording medium includes a nonmagnetic substrate on which is provided at least a soft magnetic under-film, an orientation control film that controls an orientation of a film directly above, a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate and a protective film, wherein the orientation control film has a material composition forming a C11b structure. The magnetic recording medium is manufactured by a method including carrying out, in order, at least a step of forming a soft magnetic under-film on a nonmagnetic substrate, a step of forming an orientation control film that controls an orientation of a film directly above, a step of forming a perpendicular magnetic recording film having an axis of easy magnetization oriented to be mainly perpendicular to the substrate, and a step of forming a protective film.
    Type: Grant
    Filed: July 14, 2003
    Date of Patent: August 1, 2006
    Assignees: Showa Denko K. K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Takeshi Iwasaki
  • Patent number: 7056606
    Abstract: A magnetic recording medium comprising: on a non-magnetic substrate, at least a soft magnetic undercoat film comprising a soft magnetic material; an orientation control film for controlling an orientation of a film directly above; a perpendicular magnetic film in which an axis of easy magnetization is oriented mainly perpendicularly with respect to the substrate; and a protection film, wherein the perpendicular magnetic film has a structure in which a large number of magnetic grains are separated by a grain boundary layer, and an average separating distance between the magnetic grains along a straight line which connects centers of gravity of mutually neighboring magnetic grains is 1 nm or greater.
    Type: Grant
    Filed: February 20, 2004
    Date of Patent: June 6, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 7033684
    Abstract: A magnetic recording medium comprising at least a soft magnetic layer, an orientation control film that controls the orientation of a film provided directly thereabove, an intermediate film, a perpendicular magnetic recording film of which the axis of easy magnetization is generally oriented perpendicular to a non-magnetic substrate, and a protective film, that are provided on said substrate, wherein the intermediate film has saturation magnetization Ms of at least 20 (emu/cc) and equal to or less than 200 (emu/cc), a method of manufacture thereof, and a magnetic read/write apparatus.
    Type: Grant
    Filed: July 14, 2003
    Date of Patent: April 25, 2006
    Assignees: Showa Denko K.K., Kabushiki Kaisha Toshiba
    Inventors: Kenji Shimizu, Akira Sakawaki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 6942936
    Abstract: A medium having at least a nonmagnetic substrate, soft magnetic backing layer, soft magnetic underlayer, and perpendicular magnetic recording layer, and An oxidized layer of the soft magnetic backing layer is also formed on the soft magnetic backing layer, and the soft magnetic underlayer has a three-layered structure including a first soft magnetic layer, interlayer, and second soft magnetic layer, a crystalline orientation control layer, e.g., an Ni orientation control layer is formed between the soft magnetic underlayer and the perpendicular magnetic recording layer.
    Type: Grant
    Filed: August 14, 2003
    Date of Patent: September 13, 2005
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Soichi Oikawa, Takashi Hikosaka, Hiroshi Sakai, Akira Sakawaki, Kenji Shimizu
  • Patent number: 6902835
    Abstract: A double layered perpendicular recording media having, between a soft magnetic layer and perpendicular magnetic recording layer, an alignment control layer containing an amorphous portion, a crystal size control layer, and an underlayer having one of a hexagonal closest packed structure and a face-centered cubic structure.
    Type: Grant
    Filed: June 5, 2003
    Date of Patent: June 7, 2005
    Assignees: Kabushiki Kaisha Toshiba, Showa Denko K.K.
    Inventors: Takashi Hikosaka, Takeshi Iwasaki, Futoshi Nakamura, Soichi Oikawa, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Patent number: 6884519
    Abstract: A magnetic recording medium having excellent magnetic read/write characteristics and thermal stability characteristics, and a method of manufacturing therefor, and a magnetic read/write apparatus are provided. This magnetic recording medium comprises an orientation control film 3 that controls the orientation of a film provided directly thereabove, a perpendicular magnetic film 5, of which the axis of easy magnetization is generally oriented perpendicular to a substrate, and a protective film 6, that are provided on a non-magnetic substrate 1, wherein the orientation control film 3 is made of a non-magnetic material which contains 33 to 80 at % of Ni and one or more kinds of elements selected from Sc, Y, Ti, Zr, Hf, Nb and Ta.
    Type: Grant
    Filed: September 13, 2002
    Date of Patent: April 26, 2005
    Assignees: Showa Denko K.K., Toshiba Corporation
    Inventors: Kenji Shimizu, Akira Sakawaki, Hui Yang, Hiro Mochizuki, Hiroshi Sakai, Takashi Hikosaka, Soichi Oikawa
  • Patent number: 6846581
    Abstract: Disclosed is a perpendicular magnetic recording medium, comprising a nonmagnetic substrate, a longitudinal hard magnetic multi-layered film arranged on the nonmagnetic substrate, including a nonmagnetic intermediate layer and a pair of hard magnetic layers laminated one upon the other with the nonmagnetic intermediate layer interposed therebetween, and having at least two hard magnetic layers, a longitudinal soft magnetic layer formed on the longitudinal hard magnetic multi-layered film, and a perpendicular magnetic recording layer formed on the longitudinal soft magnetic layer. The perpendicular magnetic recording medium of the particular construction is capable of suppressing noise and achieves a high recording magnetic field intensity and a high recording resolution.
    Type: Grant
    Filed: March 21, 2002
    Date of Patent: January 25, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Soichi Oikawa, Yoichiro Tanaka, Takashi Hikosaka, Futoshi Nakamura
  • Publication number: 20040229083
    Abstract: Disclosed is a magnetic recording medium which includes a substrate, an underlayer, and a perpendicular magnetic recording layer, and in which this perpendicular magnetic recording layer contains magnetic crystal grains and a matrix surrounding the magnetic crystal grains, and the matrix contains an element selected from Zn, Cd, Al, Ga, and In, and a component selected from P, As, Sb, S, Se, and Te.
    Type: Application
    Filed: March 8, 2004
    Publication date: November 18, 2004
    Applicants: KABUSHIKI KAISHA TOSHIBA, SHOWA DENKO K.K.
    Inventors: Tomoyuki Maeda, Takashi Hikosaka, Futoshi Nakamura, Takeshi Iwasaki, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki