Patents by Inventor Takahisa Kurahashi

Takahisa Kurahashi 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: 8440907
    Abstract: A solar cell includes a semiconductor substrate having a photoelectric converting portion, a first electrode formed on a first main surface of the semiconductor substrate, and a second electrode connected to the first electrode on the first main surface. The first electrode includes a plurality of first connecting portions to be connected to an interconnector and a first non-connecting portion not connected to an interconnector. The first non-connecting portion is arranged between first connecting portions to electrically connect the first connecting portions together. The first connecting portion and first non-connecting portion are coupled forming an angle larger than 90° and smaller than 180°. A solar cell string and a solar cell module employ the solar cells.
    Type: Grant
    Filed: March 15, 2007
    Date of Patent: May 14, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hirotaka Sato, Akira Miyazawa, Kyotaro Nakamura, Toshio Kimura, Masaomi Hioki
  • Publication number: 20120325291
    Abstract: A method for producing a back electrode type solar cell including the steps of forming a light-receiving surface diffusion layer and an anti-reflection film by applying, to a light-receiving surface of a silicon substrate, a solution containing a compound containing an impurity identical in conductivity type to the silicon substrate, a titanium alkoxide, and an alcohol, followed by heat treatment, and forming a light-receiving surface passivation film on the light-receiving surface of the silicon substrate by heat treatment; a back electrode type solar cell including a light-receiving surface diffusion layer, and an anti-reflection film on the light-receiving surface diffusion layer, made of titanium oxide containing an impurity identical in conductivity type to a silicon substrate; and a back electrode type solar cell module including the back electrode type solar cells.
    Type: Application
    Filed: January 27, 2011
    Publication date: December 27, 2012
    Inventors: Yuji Yokosawa, Yasushi Funakoshi, Satoshi Okamoto, Takahisa Kurahashi
  • Publication number: 20100018562
    Abstract: A solar cell includes a semiconductor substrate having a photoelectric converting portion, a first electrode formed on a first main surface of the semiconductor substrate, and a second electrode connected to the first electrode on the first main surface. The first electrode includes a plurality of first connecting portions to be connected to an interconnector and a first non-connecting portion not connected to an interconnector. The first non-connecting portion is arranged between first connecting portions to electrically connect the first connecting portions together. The first connecting portion and first non-connecting portion are coupled forming an angle larger than 90° and smaller than 180°. A solar cell string and a solar cell module employ the solar cells.
    Type: Application
    Filed: March 15, 2007
    Publication date: January 28, 2010
    Inventors: Takahisa Kurahashi, Hirotaka Sato, Akira Miyazawa, Kyotaro Nakamura, Toshio Kimura, Masaomi Hioki
  • Patent number: 7541621
    Abstract: A semiconductor light emitting device includes a first conductivity-type first semiconductor layer; an emission layer; a second conductivity-type second semiconductor layer; and a second conductivity-type transparent substrate transparent to light beams from the emission layer and directly bonded to the second semiconductor layer. The transparent substrate has a parallel surface almost parallel to the emission layer on an opposite side of the emission layer, and an inclined surface adjoining the parallel surface and inclined to the parallel surface. Light beams totally reflected on the parallel surface and light beams totally reflected on a side surface of the transparent substrate come incident to the inclined surface at an angle smaller than the critical angle, and emit out of the semiconductor light emitting device.
    Type: Grant
    Filed: August 22, 2005
    Date of Patent: June 2, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ooyama, Osamu Yamamoto
  • Patent number: 7495263
    Abstract: On a GaAs substrate (1), are formed a DBR (Distributed Bragg Reflector) (3), and a light-emitting layer (5) made of a plurality of layers of AlyGazIn1-y-zP (0?y?1, 0?z?1) above the DBR (3). A semiconductor layer or a plurality of semiconductor layers (6)-(10) having a number of layers of 1 or more are formed on the light-emitting layer (5), and a grating pattern for scattering light is formed on a surface of the semiconductor layer (9) by photolithography and by etching with a sulfuric acid/hydrogen peroxide based etchant. Thus, a semiconductor device small in radiation angle dependence of light emission wavelength, as well as a manufacturing method therefor, are provided.
    Type: Grant
    Filed: February 7, 2001
    Date of Patent: February 24, 2009
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroyuki Hosoba, Hiroshi Nakatsu, Tetsurou Murakami, Shouichi Ohyama
  • Patent number: 7348195
    Abstract: An n-type AlAs/n-type Al0.5Ga0.5As DBR layer and a p-type (Al0.2Ga0.8)0.5In0.5P/p-type Al0.5In0.5P DBR layer are formed on an n-type GaAs substrate at specified intervals so that a reflection spectrum is centered at 650 nm and the resonance wavelength becomes 650 nm. A quantum well active layer (light-emitting layer) is formed so that the light emission peak wavelength becomes 650 nm in the belly position of the standing wave generated in a resonator constructed of both the DBR layers. A grating pattern is formed on the surface of a p-type Al0.5Ga0.5As light diffusion layer that serves as a light-emitting surface surrounded by a p-type electrode. By thus roughening the light-emitting surface, light emitted from the light-emitting layer is diffused in various directions, reducing the radiation angle dependency of the emission light wavelength.
    Type: Grant
    Filed: July 28, 2004
    Date of Patent: March 25, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
  • Patent number: 7285436
    Abstract: A semiconductor light-emitting device exhibits high reflectance even with less number of pairs of light-reflecting layers, and allows light emitted from the active layer to be effectively extracted outside. This semiconductor light-emitting device is fabricated at good mass productivity by a semiconductor light-emitting device manufacturing method including the step of providing an active layer which generates light having a specified wavelength on a semiconductor substrate. On the semiconductor substrate, are stacked an AlxGa1-xAs layer and the active layer, in this order. Part of the AlxGa1-xAs layer with respect to the is changed into an AlOy layer (where y is a positive real number).
    Type: Grant
    Filed: August 17, 2004
    Date of Patent: October 23, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroshi Nakatsu, Takahisa Kurahashi, Tetsuroh Murakami, Shouichi Ooyama
  • Patent number: 7166865
    Abstract: There is provided and manufactured, at a low cost and with high yields, a semiconductor light emitting device which allows extraction of light produced in an emitter layer not only from its top surface but also from its side surfaces and which has high luminance. An AlGaInP-based semiconductor light emitting device having a contact layer 8 made of (AlyGa1?y)zIn1?zP (0?y?1, 0<z<1) disposed between an emitter layer 3 and a transparent substrate 2 which is transparent to emission wavelengths from the emitter layer 3.
    Type: Grant
    Filed: October 5, 2004
    Date of Patent: January 23, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ohyama, Hiroshi Nakatsu
  • Publication number: 20060094140
    Abstract: A manufacturing method for a semiconductor light emitting device is provided. The method includes preparing a first wafer in which at least one semiconductor layer including the emitter layer is formed; disposing a second wafer transparent to an emission wavelength of the emitter layer on the surface of the first wafer; providing a bonding failure prevention structure to at least either the first wafer or the second wafer for preventing bonding failures of the first wafer and the second wafer; and applying compressive force to a contact face between the first wafer and the second wafer while at the same time, heating the contact face. The first and second wafers can be bonded across their entire surfaces without causing bonding failure.
    Type: Application
    Filed: October 31, 2005
    Publication date: May 4, 2006
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yukari Inoguchi, Hiroshi Umeda, Takahisa Kurahashi, Nobuyuki Watanabe, Tetsuroh Murakami
  • Publication number: 20060043392
    Abstract: A semiconductor light emitting device includes a first conductivity-type first semiconductor layer; an emission layer; a second conductivity-type second semiconductor layer; and a second conductivity-type transparent substrate transparent to light beams from the emission layer and directly bonded to the second semiconductor layer. The transparent substrate has a parallel surface almost parallel to the emission layer on an opposite side of the emission layer, and an inclined surface adjoining the parallel surface and inclined to the parallel surface. Light beams totally reflected on the parallel surface and light beams totally reflected on a side surface of the transparent substrate come incident to the inclined surface at an angle smaller than the critical angle, and emit out of the semiconductor light emitting device.
    Type: Application
    Filed: August 22, 2005
    Publication date: March 2, 2006
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ooyama, Osamu Yamamoto
  • Patent number: 6924502
    Abstract: A semiconductor light emitting device has in sequence on a semiconductor substrate, a multilayer reflection film, a semiconductor layer, and a quantum well active layer. A distance between an upper surface of the multilayer reflection film and a lower surface of the quantum well active layer is 2?/n or less, where ? is a light emission wavelength and n is an average refractive index of the semiconductor layer disposed in between the multilayer reflection film and the quantum well active layer. A phase difference between a reflected ray of light reflected by the multilayer reflection film and an emitted ray of light from the quantum well active layer is a multiple of 2?. The semiconductor light emitting device stably obtains a specified peak wavelength even when there is slight variance in the distance between the upper surface of the multilayer reflection film and the lower surface of the quantum well active layer.
    Type: Grant
    Filed: October 16, 2002
    Date of Patent: August 2, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
  • Publication number: 20050116309
    Abstract: A semiconductor light-emitting element has a semiconductor laminate including an active layer emitting light of a prescribed emission wavelength and a step located at an in-depth position beyond the active layer. The element also has a substrate transparent to the emission wavelength, a first electrode provided on a surface of the semiconductor laminate, and a second electrode provided on the step. The substrate transparent to the emission wavelength improves the external emission efficiency. The locations of the first and second electrodes substantially prevent current to flow through a direct connection interface between the semiconductor laminate and the substrate. Thereby, the element exhibits satisfactory electrical characteristics even when an incomplete junction attributed to hillock or the like is generated in the direct connection interface.
    Type: Application
    Filed: October 25, 2004
    Publication date: June 2, 2005
    Inventors: Shouichi Ohyama, Tetsurou Murakamii, Takahisa Kurahashi, Osamu Yamamoto, Hiroshi Nakatsu
  • Publication number: 20050093015
    Abstract: There is provided and manufactured, at a low cost and with high yields, a semiconductor light emitting device which allows extraction of light produced in an emitter layer not only from its top surface but also from its side surfaces and which has high luminance. An AlGaInP-based semiconductor light emitting device having a contact layer 8 made of (AlyGa1-y)zIn1-zP (0?y?1, 0<z<1) disposed between an emitter layer 3 and a transparent substrate 2 which is transparent to emission wavelengths from the emitter layer 3.
    Type: Application
    Filed: October 5, 2004
    Publication date: May 5, 2005
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ohyama, Hiroshi Nakatsu
  • Patent number: 6881985
    Abstract: A light emitting diode (LED) of a double hetero-junction type has a light-emitting layer of a GaAlInP material, a p-type cladding layer and an n-type cladding layer sandwiching the light-emitting layer therebetween, a p-side electrode formed on the p-type cladding layer side, and an n-side electrode formed on the n-type cladding layer side. The p-type cladding layer consists of a first p-type cladding layer positioned closer to the light-emitting layer and having a lower aluminum content and a lower impurity concentration, and a second p-type cladding layer positioned less closer to the light-emitting layer and having a higher aluminum content and a higher impurity concentration. The LED also has a current blocking layer below the p-side electrode for locally blocking electric current flowing from the p-side electrode to the n-side electrode.
    Type: Grant
    Filed: July 21, 2003
    Date of Patent: April 19, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tetsuroh Murakami, Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba
  • Patent number: 6864514
    Abstract: A light emitting diode having, at least, an AlGaInP light emitting layer and a transparent electrode, wherein the transparent electrode is made of a ZnO film doped with a group III element or a compound thereof.
    Type: Grant
    Filed: December 3, 2003
    Date of Patent: March 8, 2005
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Tetsuroh Murakami, Hiroshi Nakatsu, Takahisa Kurahashi, Shouichi Ohyama
  • Publication number: 20050031007
    Abstract: Is provided a resonant cavity type light emitting diode having excellent humidity durability and a light output unsaturated even several 10 mA., which is suitable for mass production. The semiconductor light emitting element has a resonator formed by one set of multi-layer reflecting films disposed at a constant distance on a GaAs substrate inclined at an angle of not less than 2 degrees in the direction [011] or [0-1-1] from the plane (100) and a light emitting layer disposed at a loop position of a standing wave in the resonator, wherein a multi-layer reflecting film disposed on the GaAs substrate side is composed of plural layers of AlxGa1-xAs (0?x?1) and a multi-layer reflecting film disposed on the opposite side of the GaAs substrate is composed of plural layers of AlyGazIn1-y-zP (0?y?1, 0?z?1), thereby achieving an improved humidity durability and an increased reflection factor by increasing the number of the reflection layers.
    Type: Application
    Filed: September 3, 2004
    Publication date: February 10, 2005
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
  • Publication number: 20050012456
    Abstract: A semiconductor light-emitting device exhibits high reflectance even with less number of pairs of light-reflecting layers, and allows light emitted from the active layer to be effectively extracted outside. This semiconductor light-emitting device is fabricated at good mass productivity by a semiconductor light-emitting device manufacturing method including the step of providing an active layer which generates light having a specified wavelength on a semiconductor substrate. On the semiconductor substrate, are stacked an AlxGa1-xAs layer and the active layer, in this order. Part of the AlxGa1-xAs layer with respect to the is changed into an AlOy layer (where y is a positive real number).
    Type: Application
    Filed: August 17, 2004
    Publication date: January 20, 2005
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Hiroshi Nakatsu, Takahisa Kurahashi, Tetsuroh Murakami, Shouichi Ooyama
  • Publication number: 20050001222
    Abstract: An n-type AlAs/n-type Al0.5Ga0.5As DBR layer and a p-type (Al0.2Ga0.8)0.5In0.5P/p-type Al0.5In0.5P DBR layer are formed on an n-type GaAs substrate at specified intervals so that a reflection spectrum is centered at 650 nm and the resonance wavelength becomes 650 nm. A quantum well active layer (light-emitting layer) is formed so that the light emission peak wavelength becomes 650 nm in the belly position of the standing wave generated in a resonator constructed of both the DBR layers. A grating pattern is formed on the surface of a p-type Al0.5Ga0.5As light diffusion layer that serves as a light-emitting surface surrounded by a p-type electrode. By thus roughening the light-emitting surface, light emitted from the light-emitting layer is diffused in various directions, reducing the radiation angle dependency of the emission light wavelength.
    Type: Application
    Filed: July 28, 2004
    Publication date: January 6, 2005
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
  • Patent number: 6822266
    Abstract: A semiconductor light-emitting device includes an active layer having a single quantum well structure. The single quantum well structure enables a high-speed response such that the rise and fall time is 2.1 nsec. Further, the single quantum well active layer is doped with Zn at a concentration of 8×1017 cm−3. Thereby, the half-value width of the light-emitting spectrum is 25 nm or more, which is wider than in the case of no doping. Thus, temperature dependence of an optical output is reduced.
    Type: Grant
    Filed: May 24, 2002
    Date of Patent: November 23, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Hiroshi Nakatsu, Tetsurou Murakami, Shouichi Ohyama
  • Patent number: 6815727
    Abstract: A resonant cavity type light emitting diode has a first DBR made of n-type AlAs or Al0.5Ga0.5As, a quantum well active layer, a second DBR made of p-type (Al0.2Ga0.6)0.5In0.5P or Al0.5In0.5P, and an n-type current constriction layer on an n-type GaAs substrate. The first DBR and the second DBR form a resonator. The quantum well active layer is formed in a position of an antinode of a standing wave inside the resonator. Between the second DBR and the current constriction layer, there is provided a p-type GaP etching protection layer that has a value obtained by dividing resistivity by thickness being 1×103 &OHgr; or more. Since a current in a current flow pass formed in the current constriction layer hardly diffuses to the outside of the current flow pass, there is generated few region with low current density that causes deterioration of responsespeed in a quantum well layer. Thus, the light emitting diode has an excellent high-speed response.
    Type: Grant
    Filed: June 24, 2003
    Date of Patent: November 9, 2004
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ohyama, Hiroshi Nakatsu