Patents by Inventor Tetsuji Matsuo

Tetsuji Matsuo 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: 20080261340
    Abstract: The method is disclosed as applied to roughening the light-emitting surface of an LED wafer for reduction of the internal total reflection of the light generated. A masking film of silver is first deposited on the surface of a wafer to be diced into LED chips. Then the masking film is heated to cause its coagulation into discrete particles. Then, using the silver particles as a mask, the wafer surface is dry etched to create pits therein. The deposition of silver on the wafer surface and its thermal coagulation into particles may be either successive or concurrent.
    Type: Application
    Filed: April 16, 2008
    Publication date: October 23, 2008
    Applicant: SANKEN ELECTRIC CO., LTD.
    Inventors: Tetsuji Matsuo, Mikio Tazima, Takashi Kato
  • Patent number: 7405431
    Abstract: An LED includes a light-generating semiconductor region having an active layer sandwiched between two confining layers of opposite conductivity types for generating light. A cathode is arranged centrally on one of the opposite major surfaces of the semiconductor region from which is emitted the light. A reflector of electroconductive material is formed on the other major surface of the semiconductor region for reflecting the light back toward the light-emitting surface of the semiconductor region. For protecting the LED against breakdown from overvoltages, a zener diode is employed which takes the form of a baseplate having two semiconductor regions of opposite conductivity types sandwiched between a pair of electrodes in the form of metal layers. The protector baseplate is integrated with the light-generating semiconductor region by joining one of the metal layers to the reflector under heat and pressure, thus serving as both mechanical support and overvoltage protector for the LED.
    Type: Grant
    Filed: September 13, 2005
    Date of Patent: July 29, 2008
    Assignee: Sanken Electric Co., Ltd.
    Inventors: Hidekazu Aoyagi, Tetsuji Matsuo
  • Publication number: 20070290215
    Abstract: An LED has a light-generating semiconductor region formed on a baseplate via a metal-made reflector layer. The light-generating semiconductor region has an active layer sandwiched between a pair of claddings of opposite conductivity types. An annular marginal space is left around the reflector layer between the light-generating semiconductor region and the substrate. In order to preclude the thermal migration of the reflector metal onto the side surfaces of the light-generating semiconductor region, with a possible short-circuiting of the pair of claddings across the active layer, an anti-migration seal is received in the annular marginal space created around the reflector layer between the light-generating semiconductor region and the baseplate.
    Type: Application
    Filed: June 18, 2007
    Publication date: December 20, 2007
    Applicant: Sanken Electric Co., Ltd.
    Inventors: Takashi Kato, Junji Sato, Tetsuji Matsuo
  • Publication number: 20070114515
    Abstract: An LED is disclosed which comprises a nitride-made main semiconductor region formed on a substrate for generating light, and an electrode formed on the main semiconductor region to a thickness sufficiently small to transmit the light from the main semiconductor region. The electrode is made from a silver-base alloy, rather than from silver only, that contains an additive or additives selected to protect the electrode against oxidation and/or sulfurization and to enhance the chemical stability of the electrode without loss in contact ohmicity.
    Type: Application
    Filed: January 15, 2007
    Publication date: May 24, 2007
    Applicant: Sanken Electric Co., Ltd.
    Inventors: Hidekazu Aoyagi, Tetsuji Matsuo, Tetsuji Moku, Mikio Tazima
  • Patent number: 7199401
    Abstract: An LED includes a semiconductor region having an active layer sandwiched between two confining layers of opposite conductivity types for generating heat. A cathode is arranged centrally on one of the opposite major surfaces of the semiconductor region from which is emitted the light. Attached to the other major surface of the semiconductor region, via an ohmic contact layer, is a reflective metal layer for reflecting the light that has traversed the ohmic contact layer, back toward the semiconductor region. A transparent antidiffusion layer is interposed between the ohmic contact layer and the reflective layer in order to prevent the ohmic contact layer and the reflective layer from thermally diffusing from one into the other to the impairment of the reflectivity of the reflective layer.
    Type: Grant
    Filed: February 16, 2005
    Date of Patent: April 3, 2007
    Assignee: Sanken Electric Co., Ltd.
    Inventors: Mikio Tazima, Masahiro Sato, Hidekazu Aoyagi, Tetsuji Matsuo
  • Publication number: 20060065901
    Abstract: An LED has a light-generating semiconductor region formed on an electroconductive baseplate via a reflector layer of silver or silver-base alloy. The light-generating semiconductor region has an active layer between claddings of opposite conductivity types. An anti-migration sheath envelopes either or both of the reflector layer and light-generating semiconductor region in order to prevent the reflector metal from migrating onto the semiconductor region with the consequent possible short-circuiting of the claddings of the active layer.
    Type: Application
    Filed: September 23, 2005
    Publication date: March 30, 2006
    Inventors: Hidekazu Aoyagi, Takashi Kato, Tetsuji Matsuo
  • Publication number: 20060056123
    Abstract: An LED includes a light-generating semiconductor region having an active layer sandwiched between two confining layers of opposite conductivity types for generating light. A cathode is arranged centrally on one of the opposite major surfaces of the semiconductor region from which is emitted the light. A reflector of electroconductive material is formed on the other major surface of the semiconductor region for reflecting the light back toward the light-emitting surface of the semiconductor region. For protecting the LED against breakdown from overvoltages, a zener diode is employed which takes the form of a baseplate having two semiconductor regions of opposite conductivity types sandwiched between a pair of electrodes in the form of metal layers. The protector baseplate is integrated with the light-generating semiconductor region by joining one of the metal layers to the reflector under heat and pressure, thus serving as both mechanical support and overvoltage protector for the LED.
    Type: Application
    Filed: September 13, 2005
    Publication date: March 16, 2006
    Inventors: Hidekazu Aoyagi, Tetsuji Matsuo
  • Publication number: 20050184300
    Abstract: An LED includes a semiconductor region having an active layer sandwiched between two confining layers of opposite conductivity types for generating heat. A cathode is arranged centrally on one of the opposite major surfaces of the semiconductor region from which is emitted the light. Attached to the other major surface of the semiconductor region, via an ohmic contact layer, is a reflective metal layer for reflecting the light that has traversed the ohmic contact layer, back toward the semiconductor region. A transparent antidiffusion layer is interposed between the ohmic contact layer and the reflective layer in order to prevent the ohmic contact layer and the reflective layer from thermally diffusing from one into the other to the impairment of the reflectivity of the reflective layer.
    Type: Application
    Filed: February 16, 2005
    Publication date: August 25, 2005
    Inventors: Mikio Tazima, Masahiro Sato, Hidekazu Aoyagi, Tetsuji Matsuo