Patents by Inventor Junji Hirokane

Junji Hirokane 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: 20050281187
    Abstract: An optical disk includes a plurality of information units, each of which has a pit array made up of a phase pit on an information track and phase pits surrounding the phase pit. With this structure, information can be recorded at high density, and recorded information can be reproduced from the optical disk under stable conditions.
    Type: Application
    Filed: June 17, 2005
    Publication date: December 22, 2005
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Michinobu Mieda, Masanori Shimo, Ikuo Nakano, Toshihiko Sakai
  • Patent number: 6949302
    Abstract: A magneto-optical recording medium includes at least a first magnetic layer, a second magnetic layer and a third magnetic layer which are layered in this order, the first magnetic layer being formed of a perpendicularly magnetized film having a relatively small wall coercivity and a relatively large wall mobility compared with the third magnetic layer in the vicinity of a predetermined temperature, and the magneto-optical recording medium satisfies conditions Tc2<Tcomp1<Tc1 and Tc2<Tcomp1<Tc3 where Tcomp1 is a compensation temperature of the first magnetic layer, Tc1, Tc2 and Tc3 are Curie temperatures of the first, second and third magnetic layers, respectively.
    Type: Grant
    Filed: November 21, 2001
    Date of Patent: September 27, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Noboru Iwata, Junji Hirokane
  • Publication number: 20050170295
    Abstract: A method for forming micropatterns includes forming a thin film consisting of a single layer or of plural layers on a substrate, irradiating an energy beam to the thin film to elevate the temperature of a region to a predetermined temperature or higher to thereby modify the region of the thin film, and patterning the thin film at least in such a manner to leave over the modified region.
    Type: Application
    Filed: February 8, 2005
    Publication date: August 4, 2005
    Inventors: Junji Hirokane, Michinobu Mieda, Go Mori
  • Patent number: 6872511
    Abstract: A method for forming micropatterns includes forming a thin film consisting of a single layer or of plural layers on a substrate, irradiating an energy beam to the thin film to elevate the temperature of a region to a predetermined temperature or higher to thereby modify the region of the thin film, and patterning the thin film at least in such a manner to leave over the modified region.
    Type: Grant
    Filed: February 15, 2002
    Date of Patent: March 29, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Michinobu Mieda, Go Mori
  • Publication number: 20050013236
    Abstract: An optical disk includes a plurality of disk sheets which are laminated, and each of which has a recording face on one of the surfaces and a flat back surface, wherein the plurality of disk sheets are laminated by adhesive layers in such a manner that between adjacent two disk sheets, a back surface of one of the disk sheets, on the opposite side of the surface where the recording face is formed, faces the disk surface of the other disk sheet. The foregoing structure realizes an optical disk of desirable recording/reproducing characteristics, which is flat and has a fixed interval between recording faces, and which permits the problems of coma aberration, spherical aberration, etc., to be suppressed.
    Type: Application
    Filed: July 13, 2004
    Publication date: January 20, 2005
    Inventors: Junji Hirokane, Michinobu Mieda, Masanori Shimo
  • Patent number: 6826769
    Abstract: A recording and reproducing device of the present invention is provided to achieve the object of realizing stable and desirable recording and reproducing of information by suppressing fluttering of an optical disk by way of suppressing pressure fluctuation which is caused, for example, when an objective lens or an optical pickup with the objective lens is moved. The object is attained by a transparent stabilizer, provided between a disk and an optical pickup, which is moved with the optical pickup, and a slider which is provided to face the transparent stabilizer with the disk in between. The slider is supported to oscillate, and the surface of the slider facing the disk is flat. During rotation of the disk, the slider moves to balance the air pressure between the transparent stabilizer and the disk with that between the slider and the disk.
    Type: Grant
    Filed: December 27, 2001
    Date of Patent: November 30, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6772431
    Abstract: A disc recording element is provided with a disc substrate having a hole at its center, a circular information recording area on its surface that is concentric with the hole. A hub is fitted to the hole. The disc substrate has a relief portion thereon for position alignment of the hub.
    Type: Grant
    Filed: August 3, 2001
    Date of Patent: August 3, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Noboru Iwata, Junji Hirokane
  • Patent number: 6762989
    Abstract: An optical recording medium includes a substrate having groove and land areas, in which address pits having substantially the same depth and which are formed deeper than the groove area are provided. By thus forming the address pits deeper than the groove area, address information can be reproduced accurately, and the optical recording medium can readily be manufactured by making the address pits which are respectively formed in the groove and land areas to have substantially the same depth.
    Type: Grant
    Filed: October 25, 2002
    Date of Patent: July 13, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6690625
    Abstract: A magneto-optical recording medium is provided with at least: a recording layer, made of a perpendicular magnetization film, in which magnetized information is recorded in the form of a perpendicular direction of magnetization; a magnetic flux generating layer, made of a perpendicular magnetization film, which is exchange-coupled with the recording layer; and a read-out layer, having a perpendicular magnetization at a predetermined temperature or higher temperatures than the predetermined temperature, which copies the magnetized information of the recording layer by magneto-static coupling with the magnetic flux generating layer and the recording layer, wherein the magnetic flux generating layer is a magnetic film having a lower Curie temperature than that of the recording layer and having a larger total magnetization than that of the recording layer at a temperature at which the read-out layer has a perpendicular magnetization.
    Type: Grant
    Filed: April 25, 2002
    Date of Patent: February 10, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6678219
    Abstract: Featured is a magneto-optical storage medium including: a first magnetic layer constituted by a perpendicularly magnetized film; a second magnetic layer constituted by a perpendicularly magnetized film so as to be exchange coupled to the first magnetic layer; and a third magnetic layer magnetostatically coupled to the first and second magnetic layers at elevated temperatures, magnetization of the first magnetic layer being copied to the third magnetic layer. The second magnetic layer produces a greater peak net magnetization, has a higher Curie temperature than the first magnetic layer and produces a leaking magnetic flux. The structure enhances magnetostatic coupling forces acting between the first magnetic layer and the second magnetic layer and also between the first magnetic layer and the third magnetic layer.
    Type: Grant
    Filed: November 2, 2000
    Date of Patent: January 13, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6671234
    Abstract: A magneto-optical storage medium includes: a reproduction magnetic layer exhibiting in-plane magnetization at room temperature and changing to perpendicular magnetization at a critical temperature or higher; first and second in-plane magnetized layers with Curie temperatures in a proximity of the critical temperature and exhibiting mutually opposite magnetic polarities; and a recording magnetic layer fabricated from a perpendicularly magnetized film, the reproduction magnetic layer, the first and second in-plane magnetized layers, and the recording magnetic layer being sequentially deposited, wherein the reproduction magnetic layer is exchange-coupled with the first and second in-plane magnetized layers at least at room temperature.
    Type: Grant
    Filed: June 28, 2000
    Date of Patent: December 30, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6665235
    Abstract: Featured is a recording and reproducing method of a magneto-optical recording medium including a recording layer for recording thereon information magneto-optically and a readout layer which has in-plane magnetization at room temperature and where a transition occurs from in-plane magnetization to perpendicular magnetization as temperature raises. The method includes projecting a light beam onto such a magneto-optical recording medium so as to form a perpendicularly magnetized area in the readout layer by duplication of the magnetization of said recording layer to the area. In further embodiments, the recording medium further includes an intermediate layer made of non-magnetic film formed between the readout and recording layers and the readout and recording layers are composed of rare-earth transition metal alloys such as TbFeCo (recoding layer) readout layer, made of GdFeCo (readout layer).
    Type: Grant
    Filed: August 8, 2002
    Date of Patent: December 16, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshiteru Murakami, Junji Hirokane, Junichiro Nakayama, Junsaku Nakajima, Akira Takahashi, Kenji Ohta, Naoyasu Iketani
  • Patent number: 6630219
    Abstract: In the present invention, in a pre-recorded information recording region on an optical disk capable of recording in both a land and a groove, a first address region is displaced off a second address region along the length of the track. Address information is stored by a first pit string P1 following a groove G1 in the first address region and by a second pit string P2 following a groove G2 in the second address region. The first pit string P1 and the second pit string P2 are adapted so that the gaps between pits constituting those strings in accordance with address information are equal to, or less than, the width of the pits measured in a radial direction of the disk. Thus, the present invention offers an optical disk and a recording/reproducing device which effect a stable tracking control.
    Type: Grant
    Filed: January 26, 2001
    Date of Patent: October 7, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Publication number: 20030081510
    Abstract: A magneto-optical recording medium is composed of a base which has a property that a light can be transmitted therethrough, a readout layer formed on the base, which has in-plane magnetization at room temperature, whereas, a transition occurs from in-plane magnetization to perpendicular magnetization as the temperature thereof is raised and a recording layer formed on the readout layer for recording information magneto-optically. A recording and reproducing method and the optical head are designed for the magneto-optical recording medium. By the recording and reproducing method using the optical head, information recorded at high density can be reproduced.
    Type: Application
    Filed: August 8, 2002
    Publication date: May 1, 2003
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshiteru Murakami, Junji Hirokane, Junichiro Nakayama, Junsaku Nakajima, Akira Takahashi, Kenji Ohta, Naoyasu Iketani
  • Patent number: 6545955
    Abstract: The magneto-optical storage medium includes: a reproduction layer exhibiting in-plane magnetization at room temperature and changing to perpendicular magnetization above a transition temperature Tp1; a first in-plane magnetized layer disposed adjacent the reproduction layer and constituted by an in-plane magnetized film having a Curie temperature Tc2 around the transition temperature Tp1; a storage layer constituted by a perpendicularly magnetized film for storing information; and at least one supplementary reproduction section, interposed between the storage layer and the first in-plane magnetized layer, constituted by a first supplementary reproduction layer and a second in-plane magnetized layer, the first supplementary reproduction layer exhibiting in-plane magnetization at room temperature and changing to perpendicular magnetization above a transition temperature Tp3, the second in-plane magnetized layer being disposed adjacent the first supplementary reproduction layer and constituted by an in-pla
    Type: Grant
    Filed: July 28, 2000
    Date of Patent: April 8, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Noboru Iwata, Junji Hirokane
  • Publication number: 20030053407
    Abstract: An optical recording medium includes a substrate having groove and land areas, in which address pits having substantially the same depth and which are formed deeper than the groove area are provided. By thus forming the address pits deeper than the groove area, address information can be reproduced accurately, and the optical recording medium can readily be manufactured by making the address pits which are respectively formed in the groove and land areas to have substantially the same depth.
    Type: Application
    Filed: October 25, 2002
    Publication date: March 20, 2003
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6534162
    Abstract: A magneto-optical recording medium includes at least: a reproducing magnetic layer composed at least of Gd and Co showing an in-plane magnetization state at room temperature and a transition to a perpendicular magnetization state at temperatures of not lower than a critical temperature; and a recording magnetic layer formed of a perpendicular magnetization film, the reproducing magnetic layer and the recording magnetic layer being magneto-statically coupled at least in the vicinity of the critical temperature, the reproducing magnetic layer containing at least either Tb or Dy so as to increase the total magnetization at a temperature at which a perpendicular magnetic anisotropy constant and a diamagnetic field energy are equal to each other.
    Type: Grant
    Filed: June 29, 2000
    Date of Patent: March 18, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6510129
    Abstract: An optical recording medium includes a substrate having groove and land areas, in which address pits having substantially the same depth and which are formed deeper than the groove area are provided. By thus forming the address pits deeper than the groove area, address information can be reproduced accurately, and the optical recording medium can readily be manufactured by making the address pits which are respectively formed in the groove and land areas to have substantially the same depth.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: January 21, 2003
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Junji Hirokane, Noboru Iwata
  • Publication number: 20020172113
    Abstract: An optical read/write apparatus causes a read/write light beam from illuminating means to strike only one side of an optical storage medium including stacked data storage layers each of which is readable/writeable separately from the other layers. In this case, the optical read/write apparatus operates so that data is read/written from/into a second data storage layer after fully recording a recordable area of a first data storage layer. Thus, light can be shone with uniform intensity across the substantially entire recordable area of the second data storage layer without using a complex read/write system even under such conditions that the transmittance to light of the first data storage layer in the recordable area may vary depending on whether any data is recorded in the recordable area.
    Type: Application
    Filed: May 10, 2002
    Publication date: November 21, 2002
    Inventors: Junji Hirokane, Noboru Iwata
  • Patent number: 6483785
    Abstract: Featured is a recording and reproducing method for recording and reproducing information on and from a recording medium. The medium includes a base having a property that a light can be transmitted therethrough, a readout layer formed on the base, which has an in-plane magnetization at room temperature, whereas, a transition occurs from in-plane magnetization to perpendicular magnetization as temperature rises and a recording layer formed on said readout layer for recording thereon information magneto-optically. A groove for guiding a light beam is formed on a readout layer side of the base and a groove width is set substantially equal to a land width formed between grooves. The recording layer on the grooves and the recording layer on lands are used in recording and reproducing information.
    Type: Grant
    Filed: October 10, 2000
    Date of Patent: November 19, 2002
    Inventors: Yoshiteru Murakami, Junji Hirokane, Junichiro Nakayama, Junsaku Nakajima, Akira Takahashi, Kenji Ohta, Naoyasu Iketani