Patents by Inventor Hideki Akasaka
Hideki Akasaka 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).
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Patent number: 5680373Abstract: In a magnetooptical reproducing apparatus and method, data recorded in a first layer of a magnetooptical recording medium is transcribed to a second layer by a reproduction magnetic field and is optically reproduced from the second layer.Type: GrantFiled: January 9, 1995Date of Patent: October 21, 1997Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5539709Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatioType: GrantFiled: July 16, 1993Date of Patent: July 23, 1996Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5475657Abstract: An overwrite capable magnetooptical recording apparatus comprises a moving magnetooptical recording medium to which is applied an initial magnetic field and a laser beam which irradiates the moving medium. The beam intensity is modulated, in accordance with binary data to be recorded, between a high beam intensity level that provides the medium with a first temperature suitable for forming one of a first bit having upward-magnetization and a second bit having downward-magnetization, and a low beam intensity level that provides the medium with a second temperature suitable for forming the other bit. A bias magnetic field is applied to a portion of the medium irradiated by the beam.Type: GrantFiled: July 16, 1993Date of Patent: December 12, 1995Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5458987Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatioType: GrantFiled: July 16, 1993Date of Patent: October 17, 1995Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5440531Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatioType: GrantFiled: July 15, 1994Date of Patent: August 8, 1995Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5389455Abstract: A medium includes a readout layer, a memory layer, an adjusting layer for an exchange coupling force .sigma..sub.W, and a writing layer, and can perform an over-write operation upon radiation of a modulated laser beam. The readout layer essentially consists of GdFeCo, the memory layer essentially consists of TbFeCo, the adjusting layer essentially consists of GdFeCo, and the writing layer essentially consists of DyFeCo. The C/N ratio of the medium exceeds 53 dB. The C/N ratio is a value obtained when a plurality of mark.sup.H having a period of 1.6 .mu.m are written, and are read out so that medium noise is maximized as compared to other noise components.Type: GrantFiled: September 21, 1992Date of Patent: February 14, 1995Assignee: Nikon CorporationInventors: Jun Saito, Tetsuo Hosokawa, Akio Okamuro, Hiroyuki Matsumoto, Haruhisa Iida, Satomi Kokai, Hideki Akasaka
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Patent number: 5367507Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatioType: GrantFiled: July 16, 1993Date of Patent: November 22, 1994Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5293291Abstract: A device comprises five wave guides and two interposed TE-TM mode splitters, formed on a substrate. A first mode splitter splits a first wave guide into second and third wave guides, and a second mode splitter splits a third wave guide into fourth and fifth wave guides. A light beam directed to the first wave guide through the second wave guide is radiated to a magneto-optical recording medium. A signal light beam carrying the information recorded on the medium, reflected by the medium, is directed to the third wave guide through the first mode splitter, and the polarization plane of the signal light beam is rotated by a polarization plane rotation device. The signal light beam is further split by the second mode splitter and directed to the fourth and fifth wave guides, thence to external detectors.Type: GrantFiled: October 19, 1992Date of Patent: March 8, 1994Assignee: Nikon CorporationInventors: Hiroshi Ohki, Masaaki Doi, Hideki Akasaka
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Patent number: 5239524Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating a laser beam onto the medium; pulse modulating an intensity of the laser beam in accordance with binary data to be recorded; when the laser beam is radiated, applying a bias field to the irradiated portion; and when the intensity of the pulse-modulated laser beam is at high level, forming one of the bit having upward-magnetizatioType: GrantFiled: December 20, 1989Date of Patent: August 24, 1993Assignee: Nikon CorporationInventors: Masatoshi Sato, Jun Saito, Hideki Akasaka
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Patent number: 5204193Abstract: A Curie temperature (Tc) writing magnetooptical recording medium which uses a dual perpendicular magnetic layer is composed of a first layer having a low Curie point (TL) and a high coercive force (HH) and a second layer having a relatively high Curie point (TH) and low coercive force (HL) and wherein data is written by applying an external magnetic field to the medium which is heated to a temperature higher than the low Curie point (TL) and lower than the high Curie point (TH). The Tc writing magnetooptical recording medium is characterized in that both the first and second layers are made of an RE-Fe-Co amorphous alloy, wherein the RE represents at least one rare earth metal selected from the group consisting of Tb, Dy, Gd and Ho.Type: GrantFiled: July 25, 1991Date of Patent: April 20, 1993Assignee: Nippon Kogaku K.K.Inventors: Masatoshi Sato, Hideki Akasaka
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Patent number: 5140654Abstract: An optical waveguide device for polarization rotation comprises a substrate, a waveguide path arranged on the substrate, a mode converting element arranged at an intermediate region of the waveguide path, and a polarization rotating element arranged at a location in the waveguide path between a place where light is incident and the mode converting element. The mode converting element includes a phase shifter for relatively shifting a phase between TE and TM components of light transmitted through the waveguide path, in response to an applied voltage, and also includes a mode converter for converting modes between the TE and TM components. The polarization rotating element rotates a polarization plane of the light transmitted through the waveguide path by (90+180 .times.n) degrees, where n is zero or an integer.Type: GrantFiled: February 19, 1991Date of Patent: August 18, 1992Assignee: Nikon CorporationInventors: Hideki Akasaka, Hiroshi Ohki, Masaaki Doi
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Patent number: 5014252Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical-recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged and that of the reference layer is aligned either upward or downward; radiating two adjacent laser beams, i.e.Type: GrantFiled: August 22, 1990Date of Patent: May 7, 1991Assignee: Nikon CorporationInventors: Hideki Akasaka, Masatoshi Sato
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Patent number: 4855975Abstract: A magnetooptical recording method for recording data using a bit having upward-magnetization and a bit having downward-magnetization on a recording layer of a magnetooptical recording medium comprises the steps of using, as the medium, a multilayered magnetic recording medium consisting of a first layer having a perpendicular magnetic anisotropy acting as a recording layer, and a second layer having a perpendicular magnetic anisotropy acting as a reference layer; moving the medium; applying an initial field so that, before recording, the direction of magnetization of the recording layer is left unchanged, and that of the reference layer is aligned either upward or downward; radiating two adjacent laser beams, i.e.Type: GrantFiled: October 5, 1987Date of Patent: August 8, 1989Assignee: Nikon CorporationInventors: Hideki Akasaka, Masatoshi Sato
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Patent number: 4853912Abstract: A magneto-optical recording process is produced by irradiating a recording track of a recording medium, in the course of movement thereof, with a main light beam of intensity sufficient for heating the medium to a temperature at which the coercive force thereof is reduced to zero or a very small value in a continuous manner during the recording operation and irradiating a separating area with a subsidiary beam of a modulated intensity, thereby modulating the vertical magnetization of said separating area. A floating magnetic field generated by the thus modulated vertical magnetization generates magnetic fields of mutually different directions, thus forming a record bit on the recording track.Type: GrantFiled: December 8, 1987Date of Patent: August 1, 1989Assignee: Nikon CorporationInventors: Hideki Akasaka, Masatoshi Sato
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Patent number: 4753853Abstract: A double-layered magnetooptical recording medium consists of two exchange-coupled layers that permit perpendicular magnetization, one layer having a low Curie point and a high coercive force and the other layer having a high Curie point and a low coercive force. The layer having low coercive force is made of a transition metal rich amporphous Gd.sub.U (Fe.sub.V Co.sub.100-V).sub.100-U alloy having the following compositional range, and the layer having high coercive force is made of a transition metal rich amorphous Tb.sub.W Fe.sub.100-W alloy having the following compositional range:U=20-26 atomic %,V=50-80 atomic %, andW=27-33 atomic %.Type: GrantFiled: March 26, 1985Date of Patent: June 28, 1988Assignee: Nippon Kogaku K.K.Inventors: Masatoshi Sato, Hideki Akasaka
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Patent number: 4433901Abstract: An improvement in an all solid type electrochromic display element comprising a first electrode, a first oxidation-reduction reaction film layer, an insulating film layer, a second oxidation-reduction reaction film layer and a second electrode laminated in this order. The improvement is characterized in that only one of the first and second oxidation-reduction film layers is patterned.Type: GrantFiled: June 1, 1981Date of Patent: February 28, 1984Assignee: Nippon Kogaku K.K.Inventors: Yosuke Takahashi, Hideki Akasaka, Toshikatsu Kasui, Tatsuo Niwa, Tsuneo Sukegawa
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Patent number: 4350414Abstract: The all solid-state ECD of the present invention features a structure composed of an oxidizable film capable of a redox reaction and showing a change in the transmittance in a certain wavelength range in the oxidized state, a reducible film capable of a redox reaction and showing a change in the transmittance in a certain wavelength range in the reduced state, an insulating film provided between said films and allowing proton conduction but prohibiting electron conduction, and a pair of electrodes between which said three films are maintained, wherein said oxidizable film is substantially composed of iridium hydroxide and/or nickel hydroxide, while said reducible film is substantially composed of tungsten oxide and/or molybdenum oxide.The ECD shows several faster response speeds, a significantly reduced voltage and the change in the transmittance improved more than six times with a drive voltage reduced to 1/8.Type: GrantFiled: June 18, 1980Date of Patent: September 21, 1982Assignee: Nippon Kogaku K. K.Inventors: Yosuke Takahashi, Hideki Akasaka, Toshikatsu Kasui, Tatsuo Niwa
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Patent number: 4135790Abstract: An electrochromic element comprising a composite cell composed of a lamination of a plurality of unit cells, at least in partial registry with one another; each of said unit cells having a pair of transparent flat electrodes at least in partial registry with one another and an electrochromic material filling a space between said transparent electrodes, and a transparent substrate for supporting said composite cell.Type: GrantFiled: April 25, 1977Date of Patent: January 23, 1979Assignee: Nippon Kogaku K.K.Inventors: Youske Takahashi, Hideki Akasaka
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Patent number: 3936136Abstract: A three-layer anti-reflection film for ultraviolet range comprises a first layer having a refractive index n.sub.1 determined so as to provide a great dispersion effect in the peripheral range, a second layer having a refractive index n.sub.2, and a third layer having a refractive index n.sub.1. The three layers are arranged symmetrically. The first and third layers are provided with an asymmetry so that an intended refractive index n* for the ultraviolet range from 200m.mu. to 400m.mu. may be obtained. The film has a predetermined optical thickness.Type: GrantFiled: November 19, 1973Date of Patent: February 3, 1976Assignee: Nippon Kogaku K.K.Inventors: Hideo Ikeda, Hideki Akasaka