Patents by Inventor Keigo Hoshikawa
Keigo Hoshikawa 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: 11795568Abstract: A production apparatus for a metal oxide single crystal according to one aspect of the present invention includes: a furnace having an interior heated to a temperature of 1,500° C. or more in an oxidative atmosphere, a heater heating the interior of the furnace, an inlet pipe being disposed in a lower part of the furnace and connecting an interior and an exterior of the furnace, an exhaust pipe being disposed in an upper part of the furnace and connecting an interior and an exterior of the furnace, a duct being disposed above the furnace, and an exhaust fan and a harmful substance elimination device being disposed in the middle of the duct.Type: GrantFiled: December 20, 2021Date of Patent: October 24, 2023Assignees: FUJIKOSHI MACHINERY CORP., SHINSHU UNIVERSITYInventors: Keigo Hoshikawa, Toshinori Taishi, Takumi Kobayashi, Yoshio Otsuka, Etsuko Ohba
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Publication number: 20230235478Abstract: A production apparatus for a metal oxide single crystal according to the present invention includes a crucible for housing a crystal raw material and a seed crystal, which has a first end and a second end, and in which the crystal raw material is disposed on a first end side, and the seed crystal is disposed on a second end side, a heater that heats the crucible, and a cooling rod, which has a third end and a fourth end, and in which the third end is provided in contact with or in proximity to the second end of the crucible so as to cool the second end by depriving the second end of heat.Type: ApplicationFiled: December 8, 2022Publication date: July 27, 2023Inventors: Keigo HOSHIKAWA, Toshinori TAISHI, Takumi KOBAYASHI
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Patent number: 11674238Abstract: A crucible for growing a metal oxide single crystal is provided that can facilitate the balance between the thickness and the strength (hardness) of the constant diameter portion of the crucible and is capable of performing growth of a crystal having a large diameter. The crucible according to the present invention is a crucible for growing a metal oxide single crystal, including a reinforcing belt material provided on an outer periphery of a constant diameter portion of the crucible. It is possible that the crucible has an upper portion having a thickness that is smaller than a thickness of a lower portion of the crucible, and the upper portion of the crucible is the constant diameter portion.Type: GrantFiled: January 26, 2021Date of Patent: June 13, 2023Assignee: FUJIKOSHI MACHINERY CORP.Inventors: Keigo Hoshikawa, Takumi Kobayashi, Yoshio Otsuka
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Patent number: 11674239Abstract: A gallium oxide crystal manufacturing device includes a crucible to hold a gallium oxide source material therein, a crucible support that supports the crucible from below, a crucible support shaft that is connected to the crucible support from below and vertically movably supports the crucible and the crucible support, a tubular furnace core tube that surrounds the crucible, the crucible support and the crucible support shaft, a tubular furnace inner tube that surrounds the furnace core tube, and a resistive heating element including a heat-generating portion placed in a space between the furnace core tube and the furnace inner tube. Melting points of the furnace core tube and the furnace inner tube are not less than 1900° C. A thermal conductivity of a portion of the furnace core tube located directly next to the crucible in a radial direction thereof is higher than a thermal conductivity of the furnace inner tube.Type: GrantFiled: February 24, 2021Date of Patent: June 13, 2023Assignees: Fujikoshi Machinery Corp., Shinshu University, Novel Crystal Technology, Inc.Inventors: Keigo Hoshikawa, Takumi Kobayashi, Yoshio Otsuka, Toshinori Taishi
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Publication number: 20220243358Abstract: A production apparatus for a metal oxide single crystal according to one aspect of the present invention includes: a furnace having an interior heated to a temperature of 1,500° C. or more in an oxidative atmosphere, a heater heating the interior of the furnace, an inlet pipe being disposed in a lower part of the furnace and connecting an interior and an exterior of the furnace, an exhaust pipe being disposed in an upper part of the furnace and connecting an interior and an exterior of the furnace, a duct being disposed above the furnace, and an exhaust fan and a harmful substance elimination device being disposed in the middle of the duct.Type: ApplicationFiled: December 20, 2021Publication date: August 4, 2022Inventors: Keigo HOSHIKAWA, Toshinori TAISHI, Takumi KOBAYASHI, Yoshio OTSUKA, Etsuko OHBA
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Publication number: 20220243357Abstract: There is provided a production apparatus for a gallium oxide crystal using the vertical Bridgman method and a production method using the production apparatus. A production apparatus for a gallium oxide crystal using a vertical Bridgman method including: a furnace body formed of a heat resistant material; a crucible shaft freely movable vertically, being extended in the furnace body, and penetrating through a bottom portion of the furnace body in the vertical direction; a crucible for housing a material of a gallium oxide crystal, being disposed on the crucible shaft; a body heater for heating the crucible, being disposed around a periphery of the crucible; and an annealing chamber for annealing the crucible, being disposed under the furnace body, and being connected to a furnace space in the furnace body.Type: ApplicationFiled: November 23, 2021Publication date: August 4, 2022Inventors: Keigo HOSHIKAWA, Toshinori TAISHI, Takumi KOBAYASHI, Yoshio OTSUKA
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Publication number: 20220112622Abstract: There is provided a production apparatus of a gallium oxide crystal using a resistance heater, the heater provided therein being capable of being provided at a low cost and capable of suppressing deformation and breakage due to heat. The production apparatus for a gallium oxide crystal according to one or more aspects of the present invention includes a furnace body constituted by a heat resistant material, a crucible disposed in the furnace body, and a heater disposed around the crucible, the heater being a resistance heater including a heating part and a conductive part having a larger diameter than the heating part connected to each other, the heating part being constituted by a material having heat resistance to 1,850° C., the conductive part being constituted by a material having heat resistance to 1,800° C.Type: ApplicationFiled: October 5, 2021Publication date: April 14, 2022Inventors: Keigo HOSHIKAWA, Takumi KOBAYASHI, Yoshio OTSUKA, Toshinori TAISHI
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Patent number: 11248311Abstract: A sapphire ribbon of the present disclosure has a width, a thickness, and a length that are orthogonal to one another, a length direction is a growth direction, and the sapphire ribbon further has two main surfaces separate from each other in a thickness direction, and the width is at least 40 cm. Further, a monocrystalline ribbon manufacturing apparatus using EFG method according to the present disclosure includes a crucible having a width greater than a depth thereof, a die pair installed in the crucible and facing each other across a slit in the depth direction, a first heater and a second heater disposed around the crucible and facing each other in the depth direction, and a third heater and a fourth heater disposed around the crucible and facing each other in the width direction.Type: GrantFiled: March 23, 2020Date of Patent: February 15, 2022Assignee: KYOCERA CorporationInventors: Akeo Fukui, Keigo Hoshikawa
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Publication number: 20210269941Abstract: A gallium oxide crystal manufacturing device includes a crucible to hold a gallium oxide source material therein, a crucible support that supports the crucible from below, a crucible support shaft that is connected to the crucible support from below and vertically movably supports the crucible and the crucible support, a tubular furnace core tube that surrounds the crucible, the crucible support and the crucible support shaft, a tubular furnace inner tube that surrounds the furnace core tube, and a resistive heating element including a heat-generating portion placed in a space between the furnace core tube and the furnace inner tube. Melting points of the furnace core tube and the furnace inner tube are not less than 1900° C. A thermal conductivity of a portion of the furnace core tube located directly next to the crucible in a radial direction thereof is higher than a thermal conductivity of the furnace inner tube.Type: ApplicationFiled: February 24, 2021Publication date: September 2, 2021Applicants: Fujikoshi Machinery Corp., SHINSHU UNIVERSITY, Novel Crystal Technology, Inc.Inventors: Keigo HOSHIKAWA, Takumi KOBAYASHI, Yoshio OTSUKA, Toshinori TAISHI
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Publication number: 20210269940Abstract: A crucible for growing a metal oxide single crystal is provided that can facilitate the balance between the thickness and the strength (hardness) of the constant diameter portion of the crucible and is capable of performing growth of a crystal having a large diameter. The crucible according to the present invention is a crucible for growing a metal oxide single crystal, including a reinforcing belt material provided on an outer periphery of a constant diameter portion of the crucible. It is possible that the crucible has an upper portion having a thickness that is smaller than a thickness of a lower portion of the crucible, and the upper portion of the crucible is the constant diameter portion.Type: ApplicationFiled: January 26, 2021Publication date: September 2, 2021Inventors: Keigo HOSHIKAWA, Takumi KOBAYASHI, Yoshio OTSUKA
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Publication number: 20200308726Abstract: A sapphire ribbon of the present disclosure has a width, a thickness, and a length that are orthogonal to one another, a length direction is a growth direction, and the sapphire ribbon further has two main surfaces separate from each other in a thickness direction, and the width is at least 40 cm. Further, a monocrystalline ribbon manufacturing apparatus using EFG method according to the present disclosure includes a crucible having a width greater than a depth thereof, a die pair installed in the crucible and facing each other across a slit in the depth direction, a first heater and a second heater disposed around the crucible and facing each other in the depth direction, and a third heater and a fourth heater disposed around the crucible and facing each other in the width direction.Type: ApplicationFiled: March 23, 2020Publication date: October 1, 2020Inventors: Akeo FUKUI, Keigo HOSHIKAWA
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Publication number: 20200115817Abstract: A production apparatus and a production method for a gallium oxide crystal, including growing a gallium oxide single crystal by VB method, HB method, or VGF method, under an air atmosphere, by using a crucible containing a Pt—Ir-based alloy having an Ir content of 20 to 30 wt %, and the production apparatus (10) includes a vertical Bridgman furnace including: a base body (12); a furnace body (14) in a cylindrical shape having heat resistance, disposed on the base body (12); a lid member (18) occluding the furnace body (14); a heater (20) disposed inside the furnace body (14); a crucible bearing (30) disposed vertically movably penetrating through the base body (12); and a crucible (34) disposed on the crucible bearing (30), heated with the heater (20), the crucible (34) being a crucible (34) containing a Pt—Ir-based alloy having an Ir content of 20 to 30 wt %.Type: ApplicationFiled: August 30, 2019Publication date: April 16, 2020Inventors: Keigo HOSHIKAWA, Toshinori TAISHI, Takumi KOBAYASHI, Etsuko OHBA, Toshimasa HARA, Motohisa KADO
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Patent number: 10570528Abstract: The apparatus for producing a gallium oxide crystal relating to the invention contains a vertical Bridgman furnace containing: a base body; a cylindrical furnace body having heat resistance disposed above the base body; a lid member occluding the furnace body; a heater disposed inside the furnace body; a crucible shaft provided vertically movably through the base body; and a crucible disposed on the crucible shaft, heated with the heater, the crucible is a crucible containing a Pt-based alloy, the furnace body has an inner wall that is formed as a heat-resistant wall containing plural ring shaped heat-resistant members each having a prescribed height accumulated on each other, and the ring shaped heat-resistant members each contain plural divided pieces that are joined to each other to the ring shape.Type: GrantFiled: March 27, 2017Date of Patent: February 25, 2020Assignees: SHINSHU UNIVERSITY, FUJIKOSHI MACHINERY CORP.Inventors: Keigo Hoshikawa, Takumi Kobayashi, Etsuko Ohba, Jun Yanagisawa
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Patent number: 10280530Abstract: To provide a single crystal production apparatus that is capable of prolonging the lifetime of a heater, and capable of reducing the cost. A single crystal production apparatus of the present invention is the single crystal production apparatus which produces a single crystal of a metal oxide in an oxidative atmosphere, containing: a base body; a cylindrical furnace body having heat resistance disposed above the base body; a lid member occluding the furnace body; a heater disposed inside the furnace body; a high frequency coil heating the heater through high frequency induction heating; and a crucible heated with the heater, the heater containing a Pt-based alloy and having a zirconia coating on an overall surface of the heater.Type: GrantFiled: January 10, 2018Date of Patent: May 7, 2019Assignees: FUJIKOSHI MACHINERY CORP., SHINSHU UNIVERSITYInventors: Keigo Hoshikawa, Yasuyuki Fujiwara, Keiichi Kohama, Shinji Nakanishi, Takumi Kobayashi, Etsuko Ohba
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Publication number: 20180251908Abstract: To provide a single crystal production apparatus that is capable of prolonging the lifetime of a heater, and capable of reducing the cost. A single crystal production apparatus of the present invention is the single crystal production apparatus which produces a single crystal of a metal oxide in an oxidative atmosphere, containing: a base body; a cylindrical furnace body having heat resistance disposed above the base body; a lid member occluding the furnace body; a heater disposed inside the furnace body; a high frequency coil heating the heater through high frequency induction heating; and a crucible heated with the heater, the heater containing a Pt-based alloy and having a zirconia coating on an overall surface of the heater.Type: ApplicationFiled: January 10, 2018Publication date: September 6, 2018Inventors: Keigo HOSHIKAWA, Yasuyuki Fujiwara, Keiichi Kohama, Shinji Nakanishi, Takumi Kobayashi, Etsuko Ohba
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Publication number: 20170306521Abstract: The apparatus for producing a gallium oxide crystal relating to the invention contains a vertical Bridgman furnace containing: a base body; a cylindrical furnace body having heat resistance disposed above the base body; a lid member occluding the furnace body; a heater disposed inside the furnace body; a crucible shaft provided vertically movably through the base body; and a crucible disposed on the crucible shaft, heated with the heater, the crucible is a crucible containing a Pt-based alloy, the furnace body has an inner wall that is formed as a heat-resistant wall containing plural ring shaped heat-resistant members each having a prescribed height accumulated on each other, and the ring shaped heat-resistant members each contain plural divided pieces that are joined to each other to the ring shape.Type: ApplicationFiled: March 27, 2017Publication date: October 26, 2017Inventors: Keigo HOSHIKAWA, Takumi KOBAYASHI, Etsuko OHBA, Jun YANAGISAWA
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Publication number: 20150244021Abstract: Provided is a solid electrolyte single crystal having a perovskite structure and a producing method thereof. Provided is a method for producing a solid electrolyte single crystal having a perovskite structure including: a heating step of heating a raw material for producing a single crystal of a solid electrolyte having a perovskite structure to a temperature of a melting point of the solid electrolyte or more to obtain a molten body; and a cooling step of cooling the obtained molten body to a temperature of a solidifying point of the solid electrolyte or less, and the solid electrolyte single crystal having a perovskite structure produced by the method.Type: ApplicationFiled: August 29, 2013Publication date: August 27, 2015Applicants: SHINSHU UNIVERSITY, TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Yasuyuki Fujiwara, Keigo Hoshikawa
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Publication number: 20110056430Abstract: The equipment for growing a sapphire single crystal is capable of easily improving shape accuracy and positioning accuracy of a thermal shield which influence temperature distribution in a growth furnace. The thermal shield is provided in the growth furnace and encloses the cylindrical heater so as to form a hot zone. The thermal shield is constituted by a plurality of cylindrical sections, which are vertically stacked and whose radial positions are defined by a positioning mechanism. The cylindrical sections are composed of carbon felt.Type: ApplicationFiled: September 1, 2010Publication date: March 10, 2011Inventors: Keigo HOSHIKAWA, Chihiro Miyagawa, Taichi Nakamura
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Publication number: 20110017124Abstract: The method is capable of producing a sapphire single crystal without forming cracks and without using an expensive crucible. The method comprises the steps of: putting a seed crystal and a raw material in a crucible; setting the crucible in a cylindrical heater; heating the crucible; and producing temperature gradient in the cylindrical heater so as to sequentially crystallize a melt. The crucible is composed of a material having a specific linear expansion coefficient which is capable of preventing mutual stress, which is caused by a difference between a linear expansion coefficient of the crucible and that of the sapphire single crystal in a direction perpendicular to a growth axis thereof, from generating in the crucible and the sapphire single crystal, or which is capable of preventing deformation of the crucible without generating a crystal defect caused by the mutual stress in the sapphire single crystal.Type: ApplicationFiled: July 15, 2010Publication date: January 27, 2011Inventors: Keigo HOSHIKAWA, Chihiro Miyagawa, Taichi Nakamura
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Patent number: 6451108Abstract: A method for manufacturing a dislocation-free silicon single crystal, includes the steps of preparing a silicon seed crystal formed of a dislocation-free single crystal having a boron concentration of 1×1018 atoms/cm3 or more, preparing a silicon melt having a boron concentration which differs from that of the seed crystal by 7×1018 atoms/cm3 or less, and bringing the seed crystal into contact with the silicon melt to grow the silicon single crystal.Type: GrantFiled: January 23, 2001Date of Patent: September 17, 2002Assignee: President of Shinshu UniversityInventors: Keigo Hoshikawa, Xinming Huang, Tatsuo Fukami, Toshinori Taishi