Patents by Inventor Shuichi Hirukawa
Shuichi Hirukawa 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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Patent number: 8823033Abstract: A nitride semiconductor ultraviolet light-emitting device includes at least one first conductivity-type nitride semiconductor layer, a nitride semiconductor emission layer, at least one second conductivity-type nitride semiconductor layer and a transparent conductive film of crystallized Mgx1Zn1-x1O (0<x1<1) that can transmit 75% or more of light emitted from the emission layer, sequentially stacked in this order on a support substrate.Type: GrantFiled: November 29, 2012Date of Patent: September 2, 2014Assignee: Sharp Kabushiki KaishaInventors: Shuichiro Yamamoto, Shuichi Hirukawa, Masataka Ohta
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Publication number: 20130146916Abstract: A nitride semiconductor ultraviolet light-emitting device includes at least one first conductivity-type nitride semiconductor layer, a nitride semiconductor emission layer, at least one second conductivity-type nitride semiconductor layer and a transparent conductive film of crystallized Mgx1Zn1-x1O (0<x1<1) that can transmit 75% or more of light emitted from the emission layer, sequentially stacked in this order on a support substrate.Type: ApplicationFiled: November 29, 2012Publication date: June 13, 2013Inventors: Shuichiro YAMAMOTO, Shuichi HIRUKAWA, Masataka OHTA
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Patent number: 8212467Abstract: A light emitting device includes a light emitting element, a cap sealing the light emitting element, and a light conversion structural section covering an upper surface of the cap. The cap includes a base section having a hole for taking out light emitted from the light emitting element, and a glass section overlaid on the hole. The glass section is provided outside the base section, and the light conversion structural section is provided outside the glass section. According to this light emitting device, manufacturing cost can be reduced by suppressing reduction in yield.Type: GrantFiled: May 25, 2009Date of Patent: July 3, 2012Assignee: Sharp Kabushiki KaishaInventors: Makoto Sawamura, Shigetoshi Ito, Shuichi Hirukawa
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Publication number: 20110068679Abstract: Provided is a light emitting device of which manufacturing cost can be reduced by suppressing reduction in yield. The present invention relates to a light emitting device including a light emitting element (11), a cap (20) sealing the light emitting element (11), and a light conversion structural section (16) covering an upper surface of the cap (20), wherein the cap (20) includes a base section (14) having a hole for taking out light emitted from the light emitting element (11), and a glass section (15) overlaid on the hole, the glass section (15) is provided outside the base section (14), and the light conversion structural section (16) is provided outside the glass section (15).Type: ApplicationFiled: May 25, 2009Publication date: March 24, 2011Applicant: Sharp Kabushiki KaishaInventors: Makoto Sawamura, Shigetoshi Ito, Shuichi Hirukawa
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Patent number: 7816162Abstract: After a p-type cladding layer, an etching rate reducing layer and a p-type contact layer are formed in order on an n-type substrate, an etching mask is formed. Then, by using the etching mask, the p-type contact layer, the etching rate reducing layer and the p-type cladding layer are partially etched in the region outside the etching mask with an etchant. At this time, the etching rate of the layers by the etchant is slower in the etching rate reducing layer than in the p-type cladding layer and the p-type contact layer. Then, a metal thin film is formed such that the film continuously coats an upper surface and side surfaces of a ridge consisting of the above layers left after the etching step. A normal vector at a surface coated with the thin film has an upward component.Type: GrantFiled: July 9, 2009Date of Patent: October 19, 2010Assignee: Sharp Kabushiki KaishaInventors: Shuichi Hirukawa, Katsuhiko Kishimoto
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Patent number: 7760783Abstract: After a p-type cladding layer, an etching rate reducing layer and a p-type contact layer are formed in order on an n-type substrate, an etching mask is formed. Then, by using the etching mask, the p-type contact layer, the etching rate reducing layer and the p-type cladding layer are partially etched in the region outside the etching mask with an etchant. At this time, the etching rate of the layers by the etchant is slower in the etching rate reducing layer than in the p-type cladding layer and the p-type contact layer. Then, a metal thin film is formed such that the film continuously coats an upper surface and side surfaces of a ridge consisting of the above layers left after the etching step. A normal vector at a surface coated with the thin film has an upward component.Type: GrantFiled: February 22, 2006Date of Patent: July 20, 2010Assignee: Sharp Kabushiki KaishaInventors: Shuichi Hirukawa, Katsuhiko Kishimoto
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Publication number: 20090275160Abstract: After a p-type cladding layer, an etching rate reducing layer and a p-type contact layer are formed in order on an n-type substrate, an etching mask is formed. Then, by using the etching mask, the p-type contact layer, the etching rate reducing layer and the p-type cladding layer are partially etched in the region outside the etching mask with an etchant. At this time, the etching rate of the layers by the etchant is slower in the etching rate reducing layer than in the p-type cladding layer and the p-type contact layer. Then, a metal thin film is formed such that the film continuously coats an upper surface and side surfaces of a ridge consisting of the above layers left after the etching step. A normal vector at a surface coated with the thin film has an upward component.Type: ApplicationFiled: July 9, 2009Publication date: November 5, 2009Inventors: Shuichi HIRUKAWA, Katsuhiko Kishimoto
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Patent number: 7537945Abstract: Provided are a semiconductor laser device capable of stable operation at the time of high power output without damage to a resonator end surface and a method of manufacturing the same, as well as an optical transmission module and an optical disk apparatus using the semiconductor laser device. A method of manufacturing a semiconductor laser device includes a laser wafer formation step of forming a laser wafer at least having a semiconductor layer to form a resonator end surface, a cleavage step of cleaving the laser wafer in the atmosphere and forming a semiconductor laser element having the resonator end surface, a contact step of brining the resonator end surface in contact with a nitrogen containing gas containing 90-100 volume % nitrogen for one hour or longer, and a reflectance control film formation step of forming a reflectance control film in contact with the resonator end surface.Type: GrantFiled: March 30, 2007Date of Patent: May 26, 2009Assignee: Sharp Kabushiki KaishaInventors: Shuichi Hirukawa, Katsuhiko Kishimoto
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Publication number: 20070243644Abstract: Provided are a semiconductor laser device capable of stable operation at the time of high power output without damage to a resonator end surface and a method of manufacturing the same, as well as an optical transmission module and an optical disk apparatus using the semiconductor laser device. A method of manufacturing a semiconductor laser device includes a laser wafer formation step of forming a laser wafer at least having a semiconductor layer to form a resonator end surface, a cleavage step of cleaving the laser wafer in the atmosphere and forming a semiconductor laser element having the resonator end surface, a contact step of brining the resonator end surface in contact with a nitrogen containing gas containing 90-100 volume % nitrogen for one hour or longer, and a reflectance control film formation step of forming a reflectance control film in contact with the resonator end surface.Type: ApplicationFiled: March 30, 2007Publication date: October 18, 2007Inventors: Shuichi Hirukawa, Katsuhiko Kishimoto
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Patent number: 7123641Abstract: In a semiconductor laser device having an oscillation wavelength of larger than 760 nm and smaller than 800 nm, on an n-type GaAs substrate (101), there are stacked in sequence an n-type first and second lower cladding layers (103, 104), a lower guide layer (106), a strained InGaAsP multiquantum well active layer (107), an upper guide layer (109), and a p-type upper cladding layer (110). Since the lower guide layer (106) is formed of InGaP, leakage of carriers from an active region is reduced. Also, since the upper guide layer (109) is formed of AlGaAs, an overflow of carriers (electrons in particular) is suppressed.Type: GrantFiled: March 1, 2004Date of Patent: October 17, 2006Assignee: Sharp Kabushiki KaishaInventors: Shuichi Hirukawa, Hidenori Kawanishi, Katsuhiko Kishimoto
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Patent number: 7098064Abstract: Immediately after stacking of a barrier layer formed of GaAsP of a multiple-strain quantum well active layer 105 at a growth temperature of 650° C., a second upper guide layer 126 formed of AlGaAs is stacked. This second upper guide layer 126 is grown while the temperature is kept at 650° C., which is a growth temperature suitable for P-based layers. By reducing the desorption of P from the barrier layer, the roughness level of the interface between the barrier layer and the second upper guide layer 126 is lowered to 20 ? or less. Thereafter, a first upper guide layer 106 is stacked. Growth temperature of this first upper guide layer 106, which is 650° C. at a start of the growth, is started to be increased concurrently with the growth, and gradually elevated until an end of the growth so as to reach 750° C. at the end of the growth.Type: GrantFiled: September 23, 2003Date of Patent: August 29, 2006Assignee: Sharp Kabushiki KaishaInventor: Shuichi Hirukawa
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Publication number: 20060186420Abstract: After a p-type cladding layer, an etching rate reducing layer and a p-type contact layer are formed in order on an n-type substrate, an etching mask is formed. Then, by using the etching mask, the p-type contact layer, the etching rate reducing layer and the p-type cladding layer are partially etched in the region outside the etching mask with an etchant. At this time, the etching rate of the layers by the etchant is slower in the etching rate reducing layer than in the p-type cladding layer and the p-type contact layer. Then, a metal thin film is formed such that the film continuously coats an upper surface and side surfaces of a ridge consisting of the above layers left after the etching step. A normal vector at a surface coated with the thin film has an upward component.Type: ApplicationFiled: February 22, 2006Publication date: August 24, 2006Inventors: Shuichi Hirukawa, Katsuhiko Kishimoto
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Patent number: 7035304Abstract: There is provided a semiconductor laser device implementing a single transverse mode oscillation in an oscillation wavelength of 780 nm band and also having high reliability and long life in high-output driving state, and an optical disk recording and reproducing apparatus with use of the semiconductor laser device. A multiple quantum well active layer 105 is composed of InGaAsP, and a first cladding layer 103, a second cladding layer 107, a third cladding layer 109, and a first current blocking layer 112 are structured from III–V group compound semiconductor containing only As as V group element. Inside the first current blocking layer 112, a hollow portion 130 is provided in the vicinity of and approximately parallel to the ridge stripe-shaped third cladding layer 109.Type: GrantFiled: June 14, 2004Date of Patent: April 25, 2006Assignee: Sharp Kabushiki KaishaInventor: Shuichi Hirukawa
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Publication number: 20050030996Abstract: There is provided a semiconductor laser device implementing a single transverse mode oscillation in an oscillation wavelength of 780 nm band and also having high reliability and long life in high-output driving state, and an optical disk recording and reproducing apparatus with use of the semiconductor laser device. A multiple quantum well active layer 105 is composed of InGaAsP, and a first cladding layer 103, a second cladding layer 107, a third cladding layer 109, and a first current blocking layer 112 are structured from III-V group compound semiconductor containing only As as V group element. Inside the first current blocking layer 112, a hollow portion 130 is provided in the vicinity of and approximately parallel to the ridge stripe-shaped third cladding layer 109.Type: ApplicationFiled: June 14, 2004Publication date: February 10, 2005Applicant: SHARP KABUSHIKI KAISHAInventor: Shuichi Hirukawa
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Publication number: 20040223527Abstract: In a semiconductor laser device having an oscillation wavelength of larger than 760 nm and smaller than 800 nm, on an n-type GaAs substrate (101), there are stacked in sequence an n-type first and second lower cladding layers (103, 104), a lower guide layer (106), a strained InGaAsP multiquantum well active layer (107), an upper guide layer (109), and a p-type upper cladding layer (110). Since the lower guide layer (106) is formed of InGaP, leakage of carriers from an active region is reduced. Also, since the upper guide layer (109) is formed of AlGaAs, an overflow of carriers (electrons in particular) is suppressed.Type: ApplicationFiled: March 1, 2004Publication date: November 11, 2004Applicant: SHARP KABUSHIKI KAISHAInventors: Shuichi Hirukawa, Hidenori Kawanishi, Katsuhiko Kishimoto
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Publication number: 20040218645Abstract: In a semiconductor laser device having an oscillation wavelength of larger than 760 nm and smaller than 800 nm, on an n-type GaAs substrate (101), there are stacked in sequence an n-type first and second lower cladding layers (103, 104), a lower guide layer (105), a GaAs lower interface protective layer (106), an InGaAsP strained multiquantum well active layer (107), a GaAs upper interface protective layer (108), an upper guide layer (109) and a p-type upper cladding layer (110). An interface between the quantum well active layer (107) and the upper guide layer (109), and an interface between the quantum well active layer (107) and the lower guide layer (105) become steep, and also epitaxy growth of crystals becomes favorable.Type: ApplicationFiled: March 26, 2004Publication date: November 4, 2004Applicant: SHARP KABUSHIKI KAISHAInventors: Shuichi Hirukawa, Hidenori Kawanishi, Kei Yamamoto
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Publication number: 20040218647Abstract: To provide a semiconductor laser device which is highly reliable even in high-power operation and has a long lifetime, and an optical disc unit using the semiconductor laser device. A semiconductor laser device having an oscillation wavelength of larger than 760 nm and smaller than 800 nm in which, on an n-type GaAs substrate (101), there are stacked in sequence an n-type first and second lower cladding layers (103, 104), a lower guide layer (105), a quantum well active layer (107), an upper guide layer (109) and a p-type upper cladding layer (110). The quantum well active layer (107) is composed of two InGaAsP compressively strained quantum well layers and three InGaAsP barrier layers alternately disposed in a manner such that an n-side barrier layer is present on a side of the lower guide layer (105) and that a p-side barrier layer is present on a side of the upper guide layer (109). The n-side barrier layer is set to have a thickness of 130 Å, which causes holes hard to tunnel.Type: ApplicationFiled: March 23, 2004Publication date: November 4, 2004Applicant: SHARP KABUSHIKI KAISHAInventors: Shuichi Hirukawa, Hidenori Kawanishi, Kei Yamamoto, Hiroyuki Nishimoto
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Patent number: 6813299Abstract: There is provided a semiconductor laser device, which has an oscillation wavelength that is greater than 760 nm and smaller than 800 nm, high reliability, long operating life and a high output, and an optical disk reproducing and recording apparatus that employs the semiconductor laser device. At least first and second lower clad layers 103 and 133, a quantum well active layer 105 constructed of well layers and barrier layers, first and second upper clad layers 107 and 109 are laminated on a GaAs substrate 101. The well layer is made of InGaAsP. The well layer has a great layer thickness d of 160 Å, and assuming that an optical confinement coefficient in one layer of the well layer is &Ggr;, then &Ggr;/d is set at a great value of 2.2×10−4 Å−1.Type: GrantFiled: January 14, 2003Date of Patent: November 2, 2004Assignee: Sharp Kabushiki KaishaInventors: Hidenori Kawanishi, Yoshie Fujishiro, Shuichi Hirukawa
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Patent number: 6775311Abstract: There is provided a semiconductor laser device implementing a single transverse mode oscillation in an oscillation wavelength of 780 nm band and also having high reliability and long life in high-output driving state, and an optical disk recording and reproducing apparatus with use of the semiconductor laser device. A multiple quantum well active layer 105 is composed of InGaAsP, and a first cladding layer 103, a second cladding layer 107, a third cladding layer 109, and a first current blocking layer 112 are structured from III-V group compound semiconductor containing only As as V group element. Inside the first current blocking layer 112, a hollow portion 130 is provided in the vicinity of and approximately parallel to the ridge stripe-shaped third cladding layer 109.Type: GrantFiled: September 12, 2002Date of Patent: August 10, 2004Assignee: Sharp Kabushiki KaishaInventor: Shuichi Hirukawa
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Publication number: 20040125843Abstract: A semiconductor laser device has at least a first conductivity-type lower clad layers, a quantum well active layer, and a second conductivity-type upper clad layer, which are stacked on a first conductivity-type GaAs substrate. The quantum well active layer is composed of a barrier layer and a well layer which are alternately stacked and both made of an InGaAsP-based material. The quantum well active layer is grown while being doped with a second conductivity type of impurity so as for the semiconductor laser device to exhibits high reliability even at the time of high-power driving as well as long life.Type: ApplicationFiled: October 29, 2003Publication date: July 1, 2004Applicant: Sharp Kabushiki KaishaInventors: Hidenori Kawanishi, Kei Yamamoto, Shuichi Hirukawa