Patents by Inventor Tomoyuki Maeda

Tomoyuki Maeda 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: 20070148500
    Abstract: A magnetic recording medium 62 wherein a substrate 11, undercoating layers 13 and 14 formed on the substrate 11, and a magnetic recording layer 15, which include the magnetic crystal grain and the grain boundary field which encloses magnetic crystal grains, are included. The grain boundary field includes Ti oxide, and the ratio of the substance amount of the Ti oxide in the magnetic recording layer 15 is 5 mol % or more and 15 mol % or less, and the Ti oxide includes at least TiO and/or Ti2O3s.
    Type: Application
    Filed: December 24, 2004
    Publication date: June 28, 2007
    Inventors: Tomoyuki Maeda, Soichi Oikawa, Takeshi Iwasaki, Futoshi Nakamura, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Publication number: 20070141401
    Abstract: According to one embodiment, a multilayered underlayer including a first underlayer containing Cu aligned in a (111) plane and a second underlayer formed on the Cu underlayer and containing Cu and nitrogen as main components is formed.
    Type: Application
    Filed: December 19, 2006
    Publication date: June 21, 2007
    Applicants: KABUSHIKI KAISHA TOSHIBA, TOHOKU UNIVERSITY, SHOWA DENKO K.K.
    Inventors: Tomoyuki Maeda, Migaku Takahashi, Masahiro Oka
  • Publication number: 20070072012
    Abstract: To provide a magnetic recording medium having a magnetic recording layer consisting of fine crystal grains with improved orientation. The soft magnetic layer 3, the seed layer 4, the under layer 5 and the magnetic recording layer 7 are formed successively on the non-magnetic substrate 1, wherein the seed layer 4 is made of a material containing Ni, the under layer 5 has a grain isolation type structure in which grains made of a non-magnetic material are isolated in a non-magnetic matrix and the non-magnetic matrix is made of a material containing Y2O3. With this constitution, the under layer 5 has improved characteristics in terms of uniformity of grains, sharpness of grain boundary, fineness of the grains and crystal orientation, and therefore the magnetic recording layer 7 that is formed on the under layer also has improved characteristics in terms of uniformity of grains, sharpness of grain boundary, fineness of the grains and crystal orientation.
    Type: Application
    Filed: July 13, 2004
    Publication date: March 29, 2007
    Inventors: Futoshi Nakamura, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Kenji Shimizu, Hiroshi Sakai
  • Patent number: 7195827
    Abstract: A perpendicular magnetic recording medium includes a substrate, an underlayer formed on the substrate, and containing at least one element selected from the group A consisting of Pt, Pd, Rh, Ag, Au, Ir and Fe, and at least one element or compound selected from the group B consisting of C, Ta, Mo, W, Nb, Zr, Hf, V, Mg, Al, Zn, Sn, In, Bi, Pb, Cd, SiO2, MgO, Al2O3, TaC, TiC, TaN, TiN, B2O3, ZrO2, In2O3 and SnO2, and a magnetic layer formed on the underlayer, containing at least one element selected from the group consisting of Fe, Co, and Ni, and at least one element selected from the group consisting of Pt, Pd, Au and Ir, and containing crystal grains having an L10 structure.
    Type: Grant
    Filed: November 28, 2003
    Date of Patent: March 27, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Hiroyuki Hieda, Yoshiyuki Kamata
  • Publication number: 20070065955
    Abstract: A perpendicular magnetic recording medium includes: a substrate; at least one underlayer formed above the substrate; and a perpendicular magnetic recording layer formed above the at least one underlayer, an easy magnetization axis of the perpendicular magnetic recording layer being oriented perpendicular to the substrate, the perpendicular magnetic recording layer including magnetic crystal particles and grain boundaries surrounding the magnetic crystal particles, wherein the grain boundaries contain an oxide of silicon and at least one element selected from the group consisting of Li, Na, K, Rb, Cs, Ca, Sr, and Ba, and the ratio of a total amount of substance of Si, Li, Na, K, Rb, Cs, Ca, Sr, and Ba in the perpendicular magnetic recording layer is no less than 1 mol % and no more than 20 mol %.
    Type: Application
    Filed: October 5, 2004
    Publication date: March 22, 2007
    Applicants: KABUSHIKI KAISHA TOSHIBA, SHOWA DENKO K.K.
    Inventors: Tomoyuki Maeda, Soichi Okawa, Takeshi Iwasaki, Futoshi Nakamura, Hiroshi Sakai, Kenji Shimizu, Akira Sakawaki
  • Publication number: 20070042227
    Abstract: To make possible high density recording by making the structure of the perpendicular magnetic recording layer finer. A perpendicular magnetic recording medium 10 includes at least a nonmagnetic under layer 2, a perpendicular magnetic layer 3, and a protective layer which are stacked on a nonmagnetic substrate 1, wherein the perpendicular magnetic layer includes ferromagnetic crystal grains and nonmagnetic crystal grain boundary regions, wherein the crystal grain boundary region includes at least two kinds of oxide.
    Type: Application
    Filed: September 22, 2004
    Publication date: February 22, 2007
    Inventors: Takeshi Iwasaki, Soichi Oikawa, Futoshi Nakamura, Tomoyuki Maeda, Hiroshi Sakai, Akira Sakawaki, Kenji Shimizu
  • Patent number: 7173567
    Abstract: The antenna of the present invention comprises flat-plate conductive ground plane 1, first antenna element 13 with one end 13a connected to feeding point 2 and intermediate portion 13b folded by a plurality of times, which is extended upward from the ground plane 1, and second antenna element 23 with one end 23a connected to the other end 13c of the first antenna element 13, with intermediate portion 23b formed in symmetrical relation to the first antenna element 13, and also, with the other end 23c connected to the ground plane 1. Thus, it is possible to obtain a small size antenna with the antenna element lowered in height.
    Type: Grant
    Filed: January 14, 2004
    Date of Patent: February 6, 2007
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Susumu Inatsugu, Hirotaka Ishihara, Koichi Ogawa, Tomoyuki Maeda
  • Publication number: 20070026262
    Abstract: According to one embodiment, a magnetic recording medium includes a substrate, a first underlayer formed on the substrate and including an amorphous alloy containing Ni, a crystalline second underlayer formed on the first underlayer and including simple Cr or an alloy containing Cr, and a magnetic recording layer formed on the second underlayer and including at least one element of Fe and Co and at least one element of Pt and Pd, and containing magnetic crystal grains having an L10 structure. An oxygen amount remaining on the upper surface of the second underlayer is larger than an oxygen amount remaining on the lower surface of the second underlayer, and a normal line to a (001) plane of the magnetic crystal grains in the magnetic recording layer is oriented with a tilt angle in a range of 3 to 25° to a normal line to a medium plane.
    Type: Application
    Filed: July 26, 2006
    Publication date: February 1, 2007
    Applicant: Kabushiki Kaisha Toshiba
    Inventor: Tomoyuki Maeda
  • 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: 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
  • Publication number: 20060204791
    Abstract: A magnetic recording medium which is provided on a nonmagnetic substrate 1 with at least an orientation-controlling layer 3 for controlling the orientation of a layer formed directly thereon, a perpendicularly magnetic layer 4 having an easily magnetizing axis oriented mainly perpendicularly relative to the nonmagnetic substrate 1, and a protective layer 5 and characterized in that the perpendicularly magnetic layer 4 includes two or more magnetic layers, that at least one of the magnetic layers is a layer 4a having Co as a main component and containing Pt as well and containing an oxide and that at least another of the magnetic layers is a layer 4b having Co as a main component and containing Cr as well and containing no oxide.
    Type: Application
    Filed: April 7, 2004
    Publication date: September 14, 2006
    Inventors: Akira Sakawaki, Kenji Shimizu, Kazuo Kobayashi, Hiroshi Sakai, Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Futoshi Nakamura
  • Publication number: 20060141292
    Abstract: At least three underlayers, i.e., a first underlayer containing, as a main component, at least one element selected from Ag, Ir, Ni, Pd, Pt, Rh, Hf, Re, Ru, Ti, Ta, Zr, Mg, and Al, a second underlayer containing Mg or Al and Si, and a third underlayer containing, as a main component, at least one element selected from Pt, Pd, Ru, Rh, Co, and Ti, are formed between a substrate and magnetic recording layer.
    Type: Application
    Filed: December 21, 2005
    Publication date: June 29, 2006
    Applicant: Kabushiki Kaisha Toshiba
    Inventors: Takeshi Iwasaki, Akira Kikitsu, Soichi Oikawa, Tomoyuki Maeda
  • Patent number: 7054087
    Abstract: A magnetic recording-reproducing apparatus has a magnetic recording medium having a nonmagnetic substrate, and a functional layer and a recording layer formed on the nonmagnetic substrate, the recording layer exhibiting a magnetic anisotropy energy density KuRL, the functional layer developing ferromagnetism upon irradiation with light so as to exhibit a magnetic anisotropy energy density KuFL lower than the magnetic anisotropy energy density KuRL and the functional layer serving to lower the magnetic anisotropy energy density of the recording layer through exchange coupling interaction with the recording layer when the functional layer is irradiated with light, a light source which irradiates the functional layer with light, and a magnetic head having a writing head writing signal magnetization by applying a magnetic field to the recording layer and a reading head reading the signal magnetization recorded in the recording layer.
    Type: Grant
    Filed: September 21, 2004
    Date of Patent: May 30, 2006
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Tadashi Kai, Akira Kikitsu, Toshihiko Nagase, Tomoyuki Maeda, Junichi Akiyama
  • Publication number: 20060006971
    Abstract: A laminated coil array includes a laminate including a plurality of ceramic layers and a plurality of internal conductors disposed one on top of another, at least three coil conductors defined by electrically connecting internal conductors of the plurality of internal conductors and arranged in line inside the laminate, and external electrodes disposed on a surface of the laminate and electrically connected to end portions of the at least three spiral coil conductors, respectively. In the coil conductors not located on both end portions in the arrangement direction of the coil conductors, the internal conductors are arranged so as to be partially reversed.
    Type: Application
    Filed: May 18, 2005
    Publication date: January 12, 2006
    Inventors: Tomoyuki Maeda, Hideaki Matsushima
  • Patent number: 6977573
    Abstract: A laminated coil array includes a laminate including a plurality of ceramic layers and a plurality of internal conductors disposed one on top of another, at least three coil conductors defined by electrically connecting internal conductors of the plurality of internal conductors and arranged in line inside the laminate, and external electrodes disposed on a surface of the laminate and electrically connected to end portions of the at least three spiral coil conductors, respectively. In the coil conductors not located on both end portions in the arrangement direction of the coil conductors, the internal conductors are arranged so as to be partially reversed.
    Type: Grant
    Filed: May 18, 2005
    Date of Patent: December 20, 2005
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Tomoyuki Maeda, Hideaki Matsushima
  • Patent number: 6972923
    Abstract: A magnetic recording medium has a substrate, and a servo signal recording magnetic layer whose magnetization is oriented in a direction perpendicular to a surface thereof, a non-magnetic layer and a data recording magnetic layer, which are stacked on the substrate in the order mentioned. The servo signal recording magnetic layer has a coercivity higher than that of the data recording magnetic layer. The servo signal recording magnetic layer has servo tracks formed with a track pitch Tps, the servo tracks adjacent to each other in a track width direction being magnetized to opposite directions perpendicular to the film surface.
    Type: Grant
    Filed: March 26, 2003
    Date of Patent: December 6, 2005
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Junichi Akiyama, Akira Kikitsu, Tadashi Kai, Toshihiko Nagase, Tomoyuki Maeda, Hisanori Aikawa
  • Publication number: 20050214520
    Abstract: A perpendicular magnetic recording medium suitable for attaining a low noise high magnetic recording density is obtained. The medium has a small average magnetic grain diameter, a small magnetic grain diameter distribution, a high perpendicular crystallographic magnetic grain orientation and a high regularity magnetic grain arrangement. The perpendicular magnetic recording medium comprises a soft magnetic layer, a granular under-layer and a perpendicular magnetic recording layer on a substrate. The granular under-layer is formed on a metal under-layer. The metal grains in the granular layer are separated by nonmagnetic inter-grain material and are partially penetrated into the metal under-layer. The perpendicular magnetic recording layer is formed on the granular layer. Then a perpendicular magnetic recording medium shows high signal to noise ratio and excellent high-density recording characteristics.
    Type: Application
    Filed: March 15, 2005
    Publication date: September 29, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Soichi Oikawa, Takeshi Iwasaki, Tomoyuki Maeda, Akira Kikitsu
  • Publication number: 20050214588
    Abstract: Disclosed is a perpendicular magnetic recording medium including: a nonmagnetic substrate; a first underlayer formed on the nonmagnetic substrate, mainly composed of at least two kinds selected from a group consisting of Fe2O3, CO3O4, MgO, MoO3, Mn3O4, SiO2, Al2O3, TiO2, and ZrO2, and having crystal grains growing in a columnar shape and crystal grain boundaries surrounding the crystal grains; a nonmagnetic second underlayer formed on the first underlayer and having crystal grains with one of a face-centered cubic structure and a hexagonal close-packed structure growing on the crystal grains of the first underlayer; a magnetic layer formed on the second underlayer; and a protective film formed on the magnetic layer.
    Type: Application
    Filed: March 17, 2005
    Publication date: September 29, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Takeshi Iwasaki, Akira Kikitsu, Soichi Oikawa, Tomoyuki Maeda
  • Publication number: 20050214590
    Abstract: A large grain diameter under-layer of at least one selected from Cu, Ni or Rh, comprising large average diameter crystalline grains of 50 nm or more than 50 nm with the (100) crystal plane of the grains oriented parallel to the substrate surface, was formed on a substrate. Then, a magnetic recording layer was deposited on the under-layer. The magnetic recording medium carrying this structure showed very small magnetic crystalline grains in magnetic layer, and excellent overwrite characteristics and signal to noise ratio at high recording density.
    Type: Application
    Filed: March 9, 2005
    Publication date: September 29, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Soichi Oikawa, Takeshi Iwasaki
  • Publication number: 20050214592
    Abstract: A grain diameter controlling crystalline layer comprising crystalline grains of a metal selected from the group consisting essentially of Cu, Ni, Rh and Pt was formed on a substrate. Then, deposited atom layer of at least one element selected from the group consisting of oxygen and carbon was formed on the surface of the grain diameter control layer. A magnetic recording layer was deposited on the atoms deposited grain diameter controlling crystalline layer. Then a magnetic recording medium in which the magnetic crystalline grains has small grain diameter and small grain diameter distribution, and the magnetic recording medium shows increased signal to noise ratio at high recording density.
    Type: Application
    Filed: March 22, 2005
    Publication date: September 29, 2005
    Applicant: KABUSHIKI KAISHA TOSHIBA
    Inventors: Tomoyuki Maeda, Akira Kikitsu, Soichi Oikawa, Takeshi Iwasaki