Patents by Inventor Hiroshi Nakatsu
Hiroshi Nakatsu 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).
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Publication number: 20220158414Abstract: A laser element comprises a substrate; and an n-type semiconductor layer, a light emitting layer, a p-type semiconductor layer, and an electrode layer successively laminated on one principal surface of the substrate, wherein the p-type semiconductor layer includes a ridge raised in a stripe shape, the ridge including a contact layer formed in a layer including a principal surface on a side opposite to the substrate, a stepped portion defined by recessing the contact layer is formed in at least part of a boundary between a lateral surface among surfaces defining outer edges of the ridge, the lateral surface extending along a lengthwise direction of the ridge, and the principal surface of the ridge, and the electrode layer covers the principal surface of the ridge and the stepped portion.Type: ApplicationFiled: November 16, 2021Publication date: May 19, 2022Inventors: AKINORI NOGUCHI, YOSHIHIKO TANI, Hiroshi NAKATSU
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Patent number: 9620671Abstract: A nitride semiconductor light emitting element is provided with: a substrate; a buffer layer that is provided on the substrate; a base layer that is provided on the buffer layer; an n-side nitride semiconductor layer that is provided on the base layer; an MQW light emitting layer that is provided on the n-side nitride semiconductor layer; and a p-side nitride semiconductor layer that is provided on the MQW light emitting layer. An x-ray rocking curve half-value width ? (004) with respect to a (004) plane, i.e., the crystal plane of the nitride semiconductor, is 40 arcsec or less, or the x-ray rocking curve half-value width ? (102) with respect to a (102) plane is 130 arcsec or less, and the rate P (80)/P (25) between light output P (25) at 25° C. and light output P (80) at 80° C. with a same operating current is 95% or more.Type: GrantFiled: May 15, 2013Date of Patent: April 11, 2017Assignee: SHARP KABUSHIKI KAISHAInventors: Hiroshi Nakatsu, Tomoya Inoue, Kentaro Nonaka, Toshiaki Asai, Tadashi Takeoka, Yoshihiko Tani
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Publication number: 20150171263Abstract: A nitride semiconductor light emitting element is provided with: a substrate; a buffer layer that is provided on the substrate; a base layer that is provided on the buffer layer; an n-side nitride semiconductor layer that is provided on the base layer; an MQW light emitting layer that is provided on the n-side nitride semiconductor layer; and a p-side nitride semiconductor layer that is provided on the MQW light emitting layer. An x-ray rocking curve half-value width ? (004) with respect to a (004) plane, i.e., the crystal plane of the nitride semiconductor, is 40 arcsec or less, or the x-ray rocking curve half-value width ? (102) with respect to a (102) plane is 130 arcsec or less, and the rate P (80)/P (25) between light output P (25) at 25° C. and light output P (80) at 80° C. with a same operating current is 95% or more.Type: ApplicationFiled: May 15, 2013Publication date: June 18, 2015Applicant: Sharp Kabushiki KaishaInventors: Hiroshi Nakatsu, Tomoya Inoue, Kentaro Nonaka, Toshiaki Asai, Tadashi Takeoka, Yoshihiko Tani
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Patent number: 7968360Abstract: In a method of producing a nitride semiconductor light-emitting device including a nitride semiconductor active layer (105) held between an n-type nitride semiconductor layer (103, 104) and a p-type nitride semiconductor layer (106 to 108) on a substrate (101), at least any one of the n-type layer, the active layer and the p-type layer includes a multilayer film structure, and a surfactant material is supplied to a crystal growth surface just before, during or after crystal growth of a layer included in the multilayer film structure.Type: GrantFiled: June 17, 2008Date of Patent: June 28, 2011Assignee: Sharp Kabushiki KaishaInventors: Atsushi Ogawa, Satoshi Komada, Hiroki Takaoka, Hiroshi Nakatsu
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Patent number: 7893446Abstract: A nitride semiconductor light-emitting device comprises a substrate, and a first n-type nitride semiconductor layer, an emission layer, a p-type nitride semiconductor layer, a metal layer and a second n-type nitride semiconductor layer stacked on the substrate successively from the side closer to the substrate, with an electrode provided on the surface of the second n-type nitride semiconductor layer or above the surface of the second n-type nitride semiconductor layer. The metal layer is preferably made of a hydrogen-storage alloy.Type: GrantFiled: January 29, 2008Date of Patent: February 22, 2011Assignee: Sharp Kabushiki KaishaInventors: Atsushi Ogawa, Akio Aioi, Satoshi Komada, Hiroshi Nakatsu
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Patent number: 7645622Abstract: A method of producing a nitride-based semiconductor device includes the steps of growing an InxAlyGa1-x-yN (0?x, 0?y, x+y<1) buffer layer (2; 12; 22; 32; 42) on a substrate (1; 11; 21; 31; 41) at a first substrate temperature, and growing a first conductivity type nitride-based semiconductor layer (4; 14; 24; 34; 44) on the buffer layer at a second substrate temperature. The first temperature is higher than the second temperature.Type: GrantFiled: April 20, 2006Date of Patent: January 12, 2010Assignee: Sharp Kabushiki KaishaInventors: Mayuko Fudeta, Hiroshi Nakatsu
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Patent number: 7495263Abstract: 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: GrantFiled: February 7, 2001Date of Patent: February 24, 2009Assignee: Sharp Kabushiki KaishaInventors: Takahisa Kurahashi, Hiroyuki Hosoba, Hiroshi Nakatsu, Tetsurou Murakami, Shouichi Ohyama
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Publication number: 20080311695Abstract: In a method of producing a nitride semiconductor light-emitting device including a nitride semiconductor active layer (105) held between an n-type nitride semiconductor layer (103, 104) and a p-type nitride semiconductor layer (106 to 108) on a substrate (101), at least any one of the n-type layer, the active layer and the p-type layer includes a multilayer film structure, and a surfactant material is supplied to a crystal growth surface just before, during or after crystal growth of a layer included in the multilayer film structure.Type: ApplicationFiled: June 17, 2008Publication date: December 18, 2008Inventors: Atsushi Ogawa, Satoshi Komada, Hiroki Takaoka, Hiroshi Nakatsu
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Publication number: 20080179608Abstract: A nitride semiconductor light-emitting device comprises a substrate, and a first n-type nitride semiconductor layer, an emission layer, a p-type nitride semiconductor layer, a metal layer and a second n-type nitride semiconductor layer stacked on the substrate successively from the side closer to the substrate, with an electrode provided on the surface of the second n-type nitride semiconductor layer or above the surface of the second n-type nitride semiconductor layer. The metal layer is preferably made of a hydrogen-storage alloy.Type: ApplicationFiled: January 29, 2008Publication date: July 31, 2008Applicant: SHARP KABUSHIKI KAISHAInventors: Atsushi Ogawa, Akio Aioi, Satoshi Komada, Hiroshi Nakatsu
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Patent number: 7348195Abstract: 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: GrantFiled: July 28, 2004Date of Patent: March 25, 2008Assignee: Sharp Kabushiki KaishaInventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
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Patent number: 7285436Abstract: 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: GrantFiled: August 17, 2004Date of Patent: October 23, 2007Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Nakatsu, Takahisa Kurahashi, Tetsuroh Murakami, Shouichi Ooyama
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Patent number: 7217955Abstract: A semiconductor laser device includes a one-body submount composed of a predetermined material such as SiC or AlN and placed on a mounting surface. A laser diode is placed on a front portion of an upper surface of the submount. A monitoring photodiode composed of crystalline silicon is stacked on a portion of the upper surface of the submount backward from the laser diode.Type: GrantFiled: October 20, 2004Date of Patent: May 15, 2007Assignee: Sharp Kabushiki KaishaInventors: Osamu Hamaoka, Hiroshi Nakatsu, Hideki Ichikawa
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Patent number: 7166865Abstract: 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: GrantFiled: October 5, 2004Date of Patent: January 23, 2007Assignee: Sharp Kabushiki KaishaInventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ohyama, Hiroshi Nakatsu
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Publication number: 20060240584Abstract: A method of producing a nitride-based semiconductor device includes the steps of growing an InxAlyGa1-x-yN(0?x, 0?y, x+y<1) buffer layer (2; 12; 22; 32; 42) on a substrate (1; 11; 21; 31; 41) at a first substrate temperature, and growing a first conductivity type nitride-based semiconductor layer (4; 14; 24; 34; 44) on the buffer layer at a second substrate temperature. The first temperature is higher than the second temperature.Type: ApplicationFiled: April 20, 2006Publication date: October 26, 2006Applicant: SHARP KABUSHIKI KAISHAInventors: Mayuko Fudeta, Hiroshi Nakatsu
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Patent number: 7005682Abstract: A semiconductor light emitting element of a monolithic structure, including: a first-conductivity-type semiconductor substrate; an active layer formed on the first-conductivity-type semiconductor substrate; a second-conductivity-type clad layer formed on the active layer; and a current diffusion layer formed on the second-conductivity-type clad layer, wherein the active layer is of a first conductivity type.Type: GrantFiled: January 27, 2004Date of Patent: February 28, 2006Assignee: Sharp Kabushiki KaishaInventors: Kiyohisa Ohta, Hiroshi Nakatsu, Kazuaki Sasaki, Junichi Nakamura
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Patent number: 6984850Abstract: A light-emitting diode includes: a semiconductor substrate; and a layered structure, made of an AlGaInP type compound semiconductor material and provided on the semiconductor substrate. The layered structure includes: a light-emitting structure composed of a pair of cladding layers and an active layer for emitting light provided between the pair of cladding layers; and a current diffusion layer which is lattice-mismatched with the light-emitting structure. A lattice mismatch ? a/a of the current diffusion layer with respect to the light-emitting structure defined by the following expression is ?1% or smaller: ?a/a=(ad?ae)/ae where ad is a lattice constant of the current diffusion layer, and ae is a lattice constant of the light-emitting structure.Type: GrantFiled: November 7, 2003Date of Patent: January 10, 2006Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Nakatsu, Osamu Yamamoto
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Patent number: 6936858Abstract: A light-emitting diode includes: a semiconductor substrate; and a layered structure, made of an AlGaInP type compound semiconductor material and provided on the semiconductor substrate. The layered structure includes: a light-emitting structure composed of a pair of cladding layers and an active layer for emitting light provided between the pair of cladding layers; and a current diffusion layer which is lattice-mismatched with the light-emitting structure. A lattice mismatch ?a/a of the current diffusion layer with respect to the light-emitting structure defined by the following expression is ?1% or smaller: ?a/a=(ad?ae)/ae where ad is a lattice constant of the current diffusion layer, and ae is a lattice constant of the light-emitting structure.Type: GrantFiled: August 13, 1999Date of Patent: August 30, 2005Assignee: Sharp Kabushiki KaishaInventors: Hiroshi Nakatsu, Osamu Yamamoto
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Patent number: 6924502Abstract: 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: GrantFiled: October 16, 2002Date of Patent: August 2, 2005Assignee: Sharp Kabushiki KaishaInventors: Takahisa Kurahashi, Hiroshi Nakatsu, Hiroyuki Hosoba, Tetsurou Murakami
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Publication number: 20050116309Abstract: 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: ApplicationFiled: October 25, 2004Publication date: June 2, 2005Inventors: Shouichi Ohyama, Tetsurou Murakamii, Takahisa Kurahashi, Osamu Yamamoto, Hiroshi Nakatsu
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Publication number: 20050093015Abstract: 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: ApplicationFiled: October 5, 2004Publication date: May 5, 2005Applicant: Sharp Kabushiki KaishaInventors: Takahisa Kurahashi, Tetsurou Murakami, Shouichi Ohyama, Hiroshi Nakatsu