Patents by Inventor Toshiyuki Okumura

Toshiyuki Okumura 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: 5335241
    Abstract: A buried stripe type semiconductor laser device having a mesa stripe whose side faces are {111} facets and having a current confinement structure under epitaxial layers burying the mesa stripe is disclosed. The buried stripe type semiconductor laser device comprises a (100) semiconductor substrate having a stripe-shaped ridge in the <011> direction, a multi-layer film of a double hetero structure formed on the upper surface of the stripe-shaped ridge. The mutil-layer film includes a laser oscillating active layer of a smaller width than that of the stripe-shaped ridge. The current confinement means are formed at both sides of the mesa stripe on the semiconductor substrate. In addition, a method of fabricating a buried stripe type semiconductor laser device having no raised portion above a mesa stripe of a substrate is disclosed. The laser device can be mounted in position with the epitaxial layer side down, without the mesa stripe being damaged or strained.
    Type: Grant
    Filed: August 30, 1991
    Date of Patent: August 2, 1994
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Toshiyuki Okumura, Kazuhiko Inoguchi, Fumihiro Konushi, Haruhisa Takiguchi
  • Patent number: 5182758
    Abstract: A periodic gain-type semiconductor laser device in which a mesa stripe has wide portions and narrow portions alternately arranged with a period that is an integral multiple of the half-wavelength of the emitted light. A multilayer structure including an n-AlGaAs first cladding layer 103 and an AlGaAs non-doped active layer 104 formed on the mesa stripe also have wide portions and narrow portions. An n-AlGaAs current confining layer 106 covers the sides of the AlGaAs non-doped active layer 104. The height of the top surface of the n-AlGaAs current confining layer 106 matches the height of the AlGaAs non-doped active layer 104. A p-AlGaAs second cladding layer 105 is formed on the AlGaAs non-doped active layer 104 and the current confining layer 106. A driving current is not injected into the narrow portions of the AlGaAs non-doped active layer 104.
    Type: Grant
    Filed: December 4, 1991
    Date of Patent: January 26, 1993
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Mototaka Taneya, Fumihiro Konushi, Toshiyuki Okumura, Haruhisa Takiguchi
  • Patent number: 5070510
    Abstract: A semiconductor laser device having a mesa stripe whose side faces are facets of {111} planes is disclosed. In the laser device, a current blocking layer is formed on a semiconductor substrate whose main surface is a (100) plane, and a channel which is oriented along the <011> direction is formed in the current blocking layer. The mesa stripe is formed on the substrate within the channel by a selective growth technique. The mesa stripe has a multilayer structure including an active layer and is covered by a burying layer.
    Type: Grant
    Filed: December 10, 1990
    Date of Patent: December 3, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Fumihiro Konushi, Hiroshi Nakatu, Kazuhiko Inoguchi, Toshiyuki Okumura, Akinori Seki, Haruhisa Takiguchi, Chitose Nakanishi, Satoshi Sugahara, Hiroaki Kudo
  • Patent number: 5049970
    Abstract: A high resistive element is provided that constitutes an element of integrated circuits comprising an oxide film formed on a semiconductor substrate and a polysilicon film formed on the oxide film. The high resistive element is prepared by ion injection of silicon ions and conductive impurities in the oxide film through the polysilicon film.
    Type: Grant
    Filed: June 12, 1990
    Date of Patent: September 17, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kenichi Tanaka, Shigeo Onishi, Toshiyuki Okumura, Keizo Sakiyama
  • Patent number: 5031991
    Abstract: An optical coupling circuit element providing one transparent substrate, a first micro Fresnel lens formed on one side surface of said substrate, and a second micro Fresnel lens formed on the other side surface of said substrate, so that coherent light incident into said first micro Fresnel lens is projected, through said transparent substrate, on said second micro Fresnel lens to be left therefrom as a collimating beams, which is useful for directing light emitted from coherent source such as semi-conductor laser to optical communication means such as optical fiber for condensation.
    Type: Grant
    Filed: December 1, 1989
    Date of Patent: July 16, 1991
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroshi Nakatsu, Toshiyuki Okumura, Kazuhiko Inoguchi, Haruhisa Takiguchi
  • Patent number: 4980875
    Abstract: A Magneto-Optical disk having a transparent substrate, a Magneto-Optical film formed on the transparent substrate and a high corrosion-resistant film laminated on the Magneto-Optical film. The Magneto-Optical film is made of a perpendicular magnetic anisotropy material, the corrosion-resistant film is made of a metal or metal alloy. A foundation protecting layer may be formed on the transparent substrate with the Magneto-Optical film and the corrosion resistant film formed thereon. The Magneto-Optical film may be a plurality of films laminated alternately with a plurality of corrosion-resistant films.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: December 25, 1990
    Assignee: NEC Home Electronics Ltd.
    Inventors: Nobuyuki Ishiwata, Chizuko Wakabayashi, Takayuki Matsumoto, Toshiyuki Okumura, Junichi Homma, Susumu Ito