Patents by Inventor Hiroaki Okagawa
Hiroaki Okagawa 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: 8946772Abstract: A substrate for epitaxial growth of the present invention comprises: a single crystal part comprising a material different from a GaN-based semiconductor at least in a surface layer part; and an uneven surface, as a surface for epitaxial growth, comprising a plurality of convex portions arranged so that each of the convex portions has three other closest convex portions in directions different from each other by 120 degrees and a plurality of growth spaces, each of which is surrounded by six of the convex portions, wherein the single crystal part is exposed at least on the growth space, which enables a c-axis-oriented GaN-based semiconductor crystal to grow from the growth space.Type: GrantFiled: February 13, 2009Date of Patent: February 3, 2015Assignee: Mitsubishi Chemical CorporationInventors: Hiroaki Okagawa, Hiromitsu Kudo, Teruhisa Nakai, Seong-Jin Kim
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Patent number: 8829778Abstract: A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) is based on a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.Type: GrantFiled: September 30, 2013Date of Patent: September 9, 2014Assignee: Mitsubishi Chemical CorporationInventors: Hiroaki Sakuta, Kazuhiko Kagawa, Yoshihito Satou, Hiroaki Okagawa, Shin Hiraoka
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Patent number: 8716728Abstract: A nitride semiconductor light-emitting diode element 1 includes a nitride semiconductor layer 12 having a bottom surface and an upper surface and containing a light emitting layer 12b inside, and a supporting substrate 11 made from a metal is bonded to the bottom surface of the nitride semiconductor layer 12. A light reflecting depression A1 to reflect light generated in the light emitting layer 12b is formed in the bottom surface of the nitride semiconductor layer 12. According to the nitride semiconductor light-emitting diode element 1, since the light generated from the light emitting layer 12b and propagated in the nitride semiconductor layer 12 in a layer direction is reflected by the light reflecting depression A1 and its travel direction is changed, the ratio of the light incident upon the upper surface of the nitride semiconductor layer 12 within a critical angle is increased.Type: GrantFiled: October 19, 2007Date of Patent: May 6, 2014Assignee: Mitsubishi Chemical CorporationInventors: Hiromitsu Kudo, Hirokazu Taniguchi, Hiroaki Okagawa, Shin Hiraoka, Takahide Joichi, Toshihiko Shima
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Publication number: 20140042896Abstract: A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) is based on a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.Type: ApplicationFiled: September 30, 2013Publication date: February 13, 2014Applicant: Mitsubishi Chemical CorporationInventors: Hiroaki SAKUTA, Kazuhiko Kagawa, Yoshihito Satou, Hiroaki Okagawa, Shin Hiraoka
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Patent number: 8581488Abstract: A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) consists of a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.Type: GrantFiled: November 9, 2011Date of Patent: November 12, 2013Assignee: Mitsubishi Chemical CorporationInventors: Hiroaki Sakuta, Kazuhiko Kagawa, Yoshihito Satou, Hiroaki Okagawa, Shin Hiraoka
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Patent number: 8455886Abstract: A light emitting device is constituted by flip-chip mounting a GaN-based LED chip. The GaN-based LED chip includes a light-transmissive substrate and a GaN-based semiconductor layer formed on the light-transmissive substrate, wherein the GaN-based semiconductor layer has a laminate structure containing an n-type layer, a light emitting layer and a p-type layer in this order from the light-transmissive substrate side, wherein a positive electrode is formed on the p-type layer, the electrode containing a light-transmissive electrode of an oxide semiconductor and a positive contact electrode electrically connected to the light-transmissive electrode, and the area of the positive contact electrode is half or less of the area of the upper surface of the p-type layer.Type: GrantFiled: March 13, 2012Date of Patent: June 4, 2013Assignee: Mitsubishi Chemical CorporationInventors: Takahide Joichi, Hiroaki Okagawa, Shin Hiraoka, Toshihiko Shima, Hirokazu Taniguchi
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Publication number: 20120175669Abstract: A light emitting device is constituted by flip-chip mounting a GaN-based LED chip. The GaN-based LED chip includes a light-transmissive substrate and a GaN-based semiconductor layer formed on the light-transmissive substrate, wherein the GaN-based semiconductor layer has a laminate structure containing an n-type layer, a light emitting layer and a p-type layer in this order from the light-transmissive substrate side, wherein a positive electrode is formed on the p-type layer, the electrode containing a light-transmissive electrode of an oxide semiconductor and a positive contact electrode electrically connected to the light-transmissive electrode, and the area of the positive contact electrode is half or less of the area of the upper surface of the p-type layer.Type: ApplicationFiled: March 13, 2012Publication date: July 12, 2012Inventors: Takahide Joichi, Hiroaki Okagawa, Shin Hiraoka, Toshihiko Shima, Hirokazu Taniguchi
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Publication number: 20120171796Abstract: A first conductive film 104-1 of a light-transmissive conductive oxide film 104 and a positive pad electrode 105 are electrically connected through a second conductive film 104-2 of the light-transmissive conductive oxide film 104 in a GaN-based LED element 100. A contact resistance of the light-transmissive conductive oxide film 104 with a p-type layer 102-3 in a first contact portion 104A is lower than in a second contact portion 104B, so that a current supplied from the positive pad electrode 105 to the p-type layer 102-3 through the conductive oxide film 104 flows to the p-type layer 102-3 mainly through the first contact portion 104A.Type: ApplicationFiled: March 13, 2012Publication date: July 5, 2012Inventors: Shin Hiraoka, Hiroaki Okagawa, Takahide Joichi
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Publication number: 20120112626Abstract: A white light-emitting semiconductor device having improved reproducibility of bright red. The device outputs light having a blue component, a green component, and a red component. Each of the light components (blue, green, and red) consists of a light-emitting semiconductor element and/or a phosphor that absorbs light emitted by a light-emitting semiconductor element and emits light through wavelength conversion. The outputted light has a spectrum which has a maximum wavelength in the range of 615-645 nm, and the intensity at a wavelength of 580 nm of the outputted light, which has been normalized with respect to luminous flux, is 80-100% of the intensity at a wavelength of 580 nm of standard light for color rendering evaluation, which has been normalized with respect to luminous flux.Type: ApplicationFiled: November 9, 2011Publication date: May 10, 2012Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Hiroaki SAKUTA, Kazuhiko KAGAWA, Yoshihito Satou, Hiroaki Okagawa, Shin Hiraoka
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Patent number: 8158990Abstract: A light emitting device is constituted by flip-chip mounting a GaN-based LED chip. The GaN-based LED chip includes a light-transmissive substrate and a GaN-based semiconductor layer formed on the light-transmissive substrate, wherein the GaN-based semiconductor layer has a laminate structure containing an n-type layer, a light emitting layer and a p-type layer in this order from the light-transmissive substrate side, wherein a positive electrode is formed on the p-type layer, the electrode containing a light-transmissive electrode of an oxide semiconductor and a positive contact electrode electrically connected to the light-transmissive electrode, and the area of the positive contact electrode is half or less of the area of the upper surface of the p-type layer.Type: GrantFiled: October 5, 2007Date of Patent: April 17, 2012Assignee: Mitsubishi Chemical CorporationInventors: Takahide Joichi, Hiroaki Okagawa, Shin Hiraoka, Toshihiko Shima, Hirokazu Taniguchi
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Patent number: 8158994Abstract: A first conductive film 104-1 of a light-transmissive conductive oxide film 104 and a positive pad electrode 105 are electrically connected through a second conductive film 104-2 of the light-transmissive conductive oxide film 104 in a GaN-based LED element 100. A contact resistance of the light-transmissive conductive oxide film 104 with a p-type layer 102-3 in a first contact portion 104A is lower than in a second contact portion 104B, so that a current supplied from the positive pad electrode 105 to the p-type layer 102-3 through the conductive oxide film 104 flows to the p-type layer 102-3 mainly through the first contact portion 104A.Type: GrantFiled: February 20, 2008Date of Patent: April 17, 2012Assignee: Mitsubishi Chemical CorporationInventors: Shin Hiraoka, Hiroaki Okagawa, Takahide Joichi
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Publication number: 20110260196Abstract: Provided is a GaN-based LED element having a novel structure for improving output by increasing light extraction efficiency.Type: ApplicationFiled: June 30, 2011Publication date: October 27, 2011Applicant: Mitsubishi Chemical CorporationInventors: Hiroaki OKAGAWA, Shin Hiraoka, Takahide Jouichi, Toshihiko Shima
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Patent number: 8012783Abstract: The object of the present invention is to provide a semiconductor element containing an n-type gallium nitride based compound semiconductor and a novel electrode that makes an ohmic contact with the semiconductor. The semiconductor element of the present invention has an n-type Gallium nitride based compound semiconductor and an electrode that forms an ohmic contact with the semiconductor, wherein the electrode has a TiW alloy layer to be in contact with the semiconductor. According to a preferable embodiment, the above-mentioned electrode can also serve as a contact electrode. According to a preferable embodiment, the above-mentioned electrode is superior in the heat resistance. Moreover, a production method of the semiconductor element is also provided.Type: GrantFiled: April 4, 2006Date of Patent: September 6, 2011Assignee: Mitsubishi Chemical CorporationInventors: Tsuyoshi Takano, Takahide Joichi, Hiroaki Okagawa
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Publication number: 20110198560Abstract: A substrate for epitaxial growth of the present invention comprises: a single crystal part comprising a material different from a GaN-based semiconductor at least in a surface layer part; and an uneven surface, as a surface for epitaxial growth, comprising a plurality of convex portions arranged so that each of the convex portions has three other closest convex portions in directions different from each other by 120 degrees and a plurality of growth spaces, each of which is surrounded by six of the convex portions, wherein the single crystal part is exposed at least on the growth space, which enables a c-axis-oriented GaN-based semiconductor crystal to grow from the growth space.Type: ApplicationFiled: February 13, 2009Publication date: August 18, 2011Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Hiroaki Okagawa, Hiromitsu Kudo, Teruhisa Nakai, Seong-Jin Kim
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Publication number: 20110012154Abstract: Provided is a GaN-based LED element having a novel structure for improving output by increasing light extraction efficiency.Type: ApplicationFiled: November 7, 2008Publication date: January 20, 2011Applicant: Mitsubishi Chemical CorporationInventors: Hiroaki Okagawa, Shin Hiraoka, Takahide Jouichi, Toshihiko Shima
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Publication number: 20100314642Abstract: A nitride semiconductor light-emitting diode element 1 includes a nitride semiconductor layer 12 having a bottom surface and an upper surface and containing a light emitting layer 12b inside, and a supporting substrate 11 made from a metal is bonded to the bottom surface of the nitride semiconductor layer 12. A light reflecting depression A1 to reflect light generated in the light emitting layer 12b is formed in the bottom surface of the nitride semiconductor layer 12. According to the nitride semiconductor light-emitting diode element 1, since the light generated from the light emitting layer 12b and propagated in the nitride semiconductor layer 12 in a layer direction is reflected by the light reflecting depression A1 and its travel direction is changed, the ratio of the light incident upon the upper surface of the nitride semiconductor layer 12 within a critical angle is increased.Type: ApplicationFiled: October 19, 2007Publication date: December 16, 2010Applicant: MITSUBISHI CHEMICAL CORPORATIONInventors: Hiromitsu Kudo, Hirokazu Taniguchi, Hiroaki Okagawa, Shin Hiraoka, Takahide Joichi, Toshihiko Shima
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Publication number: 20100019247Abstract: A light emitting device is constituted by flip-chip mounting a GaN-based LED chip 100 of the following (a): (a) the a GaN-based LED chip 100 comprising a light-transmissive substrate 101 and GaN-based semiconductor layer L formed on the light-transmissive substrate 101, wherein the GaN-based semiconductor layer L has a laminate structure containing n-type layer 102, light emitting layer 103 and p-type layer 104 in this order from the light-transmissive substrate 101 side, wherein a positive electrode E101 is formed on the p-type layer 104, said electrode E101 containing a light-transmissive electrode E101a of an oxide semiconductor and a positive contact electrode E101b electrically connected to the light-transmissive electrode, and the area of the positive contact electrode E101b is less than ½ of the area of the upper surface of the p-type layer 104.Type: ApplicationFiled: October 5, 2007Publication date: January 28, 2010Inventors: Takahide Joichi, Hiroaki Okagawa, Shin Hiraoka, Toshihiko Shima, Hirokazu Taniguchi
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Publication number: 20100012971Abstract: A first conductive film 104-1 and a positive pad electrode 105 are electrically connected through a second conductive film 104-2 in a GaN-based LED element 100. The contact resistance of a conductive oxide film 104 with a p-type layer 102-3 in a first contact portion 104A is made lower than in a second contact portion 104B, so that a current supplied from the positive pad electrode 105 to the p-type layer 102-3 through the conductive oxide film 104 flows to the p-type layer 102-3 mainly through the first contact portion 104A.Type: ApplicationFiled: February 20, 2008Publication date: January 21, 2010Inventors: Shin Hiraoka, Hiroaki Okagawa, Takahide Joichi
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Patent number: 7589001Abstract: A growth plane of substrate 1 is processed to have a concavo-convex surface. The bottom of the concave part may be masked. When a crystal is grown by vapor phase growth using this substrate, an ingredient gas does not sufficiently reach the inside of a concave part 12, and therefore, a crystal growth occurs only from an upper part of a convex part 11. As shown in FIG. 1(b), therefore, a crystal unit 20 occurs when the crystal growth is started, and as the crystal growth proceeds, films grown in the lateral direction from the upper part of the convex part 11 as a starting point are connected to cover the concavo-convex surface of the substrate 1, leaving a cavity 13 in the concave part, as shown in FIG. 1(c), thereby giving a crystal layer 2, whereby the semiconductor base of the present invention is obtained. In this case, the part grown in the lateral direction, or the upper part of the concave part 12 has a low dislocation region and the crystal layer prepared has high quality.Type: GrantFiled: September 29, 2006Date of Patent: September 15, 2009Assignee: Mitsubishi Chemical CorporationInventors: Kazuyuki Tadatomo, Hiroaki Okagawa, Yoichiro Ouchi, Masahiro Koto
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Patent number: 7504324Abstract: A growth plane of substrate 1 is processed to have a concavo-convex surface. The bottom of the concave part may be masked. When a crystal is grown by vapor phase growth using this substrate, an ingredient gas does not sufficiently reach the inside of a concave part 12, and therefore, a crystal growth occurs only from an upper part of a convex part 11. As shown in FIG. 1(b), therefore, a crystal unit 20 occurs when the crystal growth is started, and as the crystal growth proceeds, films grown in the lateral direction from the upper part of the convex part 11 as a starting point are connected to cover the concavo-convex surface of the substrate 1, leaving a cavity 13 in the concave part, as shown in FIG. 1(c), thereby giving a crystal layer 2, whereby the semiconductor base of the present invention is obtained. In this case, the part grown in the lateral direction, or the upper part of the concave part 12 has a low dislocation region and the crystal layer prepared has high quality.Type: GrantFiled: September 29, 2006Date of Patent: March 17, 2009Assignee: Mitsubishi Chemical CorporationInventors: Kazuyuki Tadatomo, Hiroaki Okagawa, Yoichiro Ouchi, Masahiro Koto