Patents Assigned to Dowa Holdings Co., Ltd.
  • Publication number: 20110254135
    Abstract: An object of the present invention is to address the problems described herein and to provide a III-nitride semiconductor epitaxial substrate, a III-nitride semiconductor element, and a III-nitride semiconductor freestanding substrate, which have good crystallinity, not only with AlGaN, GaN, or GaInN, the growth temperature of which is at or below 1050° C., but also with AlxGa1-xN, the growth temperature of which is high and which has a high Al composition, as well as a III-nitride semiconductor growth substrate for fabricating these and a method for efficiently fabricating these. The invention is characterized by being equipped with: a crystal growth substrate, at least the surface portion of which substrate includes a III-nitride semiconductor containing Al; and a single metallic layer formed on the surface portion, the single metallic layer being made from Zr or Hf.
    Type: Application
    Filed: December 25, 2009
    Publication date: October 20, 2011
    Applicants: DOWA HOLDINGS CO., LTD., DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Ryuichi Toba, Masahito Miyashita, Tatsunori Toyota
  • Patent number: 7895957
    Abstract: A heat exchanger tube 41 includes: a first cover layer 44 provided on an outer side of a tube main body 42 to partly or completely cover a tube main body 42; and a second cover layer 45 provided on an outer side of the first cover layer 44 to partly or completely cover the first cover layer 44. The first cover layer 44 is formed by overlay-welding a material higher in ductility than the second cover layer 45 to the tube main body 42. The second cover layer 45 is formed by overlay-welding a material higher in hardness than the first cover layer 44 to the first cover layer 44.
    Type: Grant
    Filed: December 27, 2006
    Date of Patent: March 1, 2011
    Assignee: Dowa Holdings Co., Ltd.
    Inventors: Hirotoshi Inomata, Hiroshi Yoshida
  • Patent number: 7829435
    Abstract: A GaN-based thin film (thick film) is grown using a metal buffer layer grown on a substrate. (a) A metal buffer layer (210) made of, for example, Cr or Cu is vapor-deposited on a sapphire substrate (120). (b) A substrate obtained by vapor-depositing the metal buffer layer (210) on the sapphire substrate (120) is nitrided in an ammonia gas ambient, thereby forming a metal nitride layer (212). (c) A GaN buffer layer (222) is grown on the nitrided metal buffer layers (210, 212). (d) Finally, a GaN single-crystal layer (220) is grown. This GaN single-crystal layer (220) can be grown to have various thicknesses depending on the objects. A freestanding substrate can be fabricated by selective chemical etching of the substrate fabricated by the above steps. It is also possible to use the substrate fabricated by the above steps as a GaN template substrate for fabricating a GaN-based light emitting diode or laser diode.
    Type: Grant
    Filed: August 21, 2009
    Date of Patent: November 9, 2010
    Assignees: Tohoku Techno Arch Co., Ltd., Furukawa Co., Ltd., Mitsubishi Chemical Corporation, Dowa Holdings Co., Ltd., Epivalley Co., Ltd., Wavesquare Inc.
    Inventors: Takafumi Yao, Meoung-Whan Cho
  • Publication number: 20070157859
    Abstract: A heat exchanger tube 41 includes: a first cover layer 44 provided on an outer side of a tube main body 42 to partly or completely cover a tube main body 42; and a second cover layer 45 provided on an outer side of the first cover layer 44 to partly or completely cover the first cover layer 44. The first cover layer 44 is formed by overlay-welding a material higher in ductility than the second cover layer 45 to the tube main body 42. The second cover layer 45 is formed by overlay-welding a material higher in hardness than the first cover layer 44 to the first cover layer 44.
    Type: Application
    Filed: December 27, 2006
    Publication date: July 12, 2007
    Applicant: Dowa Holdings Co., Ltd.
    Inventors: Hirotoshi Inomata, Hiroshi Yoshida
  • Patent number: RE41833
    Abstract: Optical filler which is adapted to prevent the reflection of external light and improve a signal level of a signal sent from a display device by preventing attenuation thereof, and which is further adapted to prevent a change in hue of an image and to improve the hue, contrast and brightness of an image, thereby enhancing visibility. First, a liquid crystal display device (1) outputs light which is linearly polarized light. First linearly polarizing plate (2) is mounted in the filler in such a manner as to be adjusted to an axis of polarization of the linearly polarized light. Namely, the light outputted from the liquid crystal display device (1) passes through the first linearly polarizing plate (2) without being changed. The light passing through the first linearly polarizing plate (2) is then changed by a first quarter-wave phase difference plate (11) into circularly polarized light so that the phase difference between extraordinary light and ordinary light is (1/4) of the wavelength.
    Type: Grant
    Filed: January 23, 2006
    Date of Patent: October 19, 2010
    Assignee: Dowa Holdings Co., Ltd.
    Inventors: Takayuki Sawai, Teturo Ueno, Takashi Onioh, Shigeyoshi Inuyama, Kojyu Nagasaki