Patents by Inventor Tomo Kikuchi

Tomo Kikuchi 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: 8389975
    Abstract: A Group III nitride semiconductor light-emitting device comprises a substrate (1) and a light-emitting layer (5) having the multiple quantum well structure that comprises barrier layers (5a) and well layers (5b) formed of a gallium-containing Group III nitride semiconductor material provided on the substrate. Each of the well layers constituting the multiple quantum well structure is made of a Group III nitride semiconductor layer to which acceptor impurities are added, and which has thicknesses different from one another and the same conductivity type as that of the barrier layer. The present invention can provide a Group III nitride semiconductor white light-emitting device which can enhance luminous intensity, can obtain high color rendering properties has a simple structure that can be easily formed without fine adjustment of a composition of a phosphor.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: March 5, 2013
    Assignee: Showa Denko K.K.
    Inventors: Tomo Kikuchi, Takashi Udagawa
  • Patent number: 8227790
    Abstract: In a Group III nitride semiconductor light-emitting device which includes a substrate (1) and a light-emitting layer (10) having a multiple quantum well structure including a barrier layer (11b, 12b), which is provided on a surface of the substrate and formed of a Group III nitride semiconductor, and a well layer (11a, 12a) formed of an indium-containing Group III nitride semiconductor, the light-emitting layer is constituted by stacking a plurality of multilayer portions (11, 12) which have one unit multilayer portion (11m) including the well layer and the barrier layer or two or more stacked unit multilayer portions (12m). When the multilayer portion (12) includes two or more unit multilayer portions (12m), the respective well or barrier layers have the same thickness and composition, and in the respective multilayer portions (11, 12), the barrier layers of the unit multilayer portions are different in thickness with respect to one another.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: July 24, 2012
    Assignee: Showa Denko K.K.
    Inventors: Tomo Kikuchi, Takashi Udagawa
  • Publication number: 20100288998
    Abstract: A Group III nitride semiconductor light-emitting device comprises a substrate (1) and a light-emitting layer (5) having the multiple quantum well structure that comprises barrier layers (5a) and well layers (5b) formed of a gallium-containing Group III nitride semiconductor material provided on the substrate. Each of the well layers constituting the multiple quantum well structure is made of a Group III nitride semiconductor layer to which acceptor impurities are added, and which has thicknesses different from one another and the same conductivity type as that of the barrier layer. The present invention can provide a Group III nitride semiconductor white light-emitting device which can enhance luminous intensity, can obtain high color rendering properties has a simple structure that can be easily formed without fine adjustment of a composition of a phosphor.
    Type: Application
    Filed: August 28, 2008
    Publication date: November 18, 2010
    Applicant: SHOWA DENKO K.K.
    Inventors: Tomo Kikuchi, Takashi Udagawa
  • Publication number: 20100288999
    Abstract: In a Group III nitride semiconductor light-emitting device which comprises a substrate (1) and a light-emitting layer (10) having a multiple quantum well structure comprising a barrier layer (11b, 12b), which is provided on a surface of the substrate and formed of a Group III nitride semiconductor, and a well layer (11a, 12a) formed of an indium-containing Group III nitride semiconductor, the light-emitting layer is constituted by stacking a plurality of multilayer portions (11, 12) which comprise one unit multilayer portion (11m) comprising the well layer and the barrier layer or two or more stacked unit multilayer portions (12m).
    Type: Application
    Filed: August 28, 2008
    Publication date: November 18, 2010
    Applicant: Showa Denko K.K.
    Inventors: Tomo Kikuchi, Takashi Udagawa