Patents by Inventor Kiyotaka Kawamura
Kiyotaka Kawamura 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: 20240376012Abstract: Provided is a powder composition that includes, as a matrix, a zirconia having a high content of a stabilizing element and that can provide, through short-time sintering, a sintered body satisfying translucency and mechanical strength required for dental prosthetic materials, in particular, prosthetic anterior teeth. Provided is a powder composition including two or more stabilized zirconias having different contents of a stabilizing element, in which the powder composition has a content of the stabilizing element of more than 4.0 mol % and 5.8 mol % or less, a rate of change in thermal shrinkage rate per unit temperature at 1,300° C. is 0.07% C?1 or less, and the contents of the stabilizing element of the stabilized zirconias are each 8.0 mol % or less.Type: ApplicationFiled: September 15, 2022Publication date: November 14, 2024Applicant: TOSOH CORPORATIONInventors: Sho AZECHI, Yuya HIGUCHI, Hiroyuki FUJISAKI, Hitoshi NAGAYAMA, Kiyotaka KAWAMURA
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Patent number: 11746054Abstract: A method for manufacturing a zirconia sintered body includes molding a powder composition that has a yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having a yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having a yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and sintering the green body to obtain a sintered body.Type: GrantFiled: April 27, 2021Date of Patent: September 5, 2023Assignee: TOSOH CORPORATIONInventors: Kiyotaka Kawamura, Akiko Ito, Hiroyuki Fujisaki, Sho Azechi
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Publication number: 20210246075Abstract: A method for manufacturing a zirconia sintered body includes molding a powder composition that has a yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having a yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having a yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and sintering the green body to obtain a sintered body.Type: ApplicationFiled: April 27, 2021Publication date: August 12, 2021Applicant: TOSOH CORPORATIONInventors: Kiyotaka KAWAMURA, Akiko ITO, Hiroyuki FUJISAKI, Sho AZECHI
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Patent number: 11021401Abstract: Provided are a zirconia sintered body capable of being widely used as a dental material, in particular, a zirconia sintered body capable of being applied to both a dental material for a back tooth and a dental material for a front tooth and a simple and easy method for manufacturing the zirconia sintered body. The method for manufacturing a zirconia sintered body includes a molding step of molding a powder composition that has an yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having an yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having an yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and a sintering step of sintering the green body to obtain a sintered body.Type: GrantFiled: March 19, 2018Date of Patent: June 1, 2021Assignee: TOSOH CORPORATIONInventors: Kiyotaka Kawamura, Akiko Ito, Hiroyuki Fujisaki, Sho Azechi
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Publication number: 20200223756Abstract: Provided are a zirconia sintered body capable of being widely used as a dental material, in particular, a zirconia sintered body capable of being applied to both a dental material for a back tooth and a dental material for a front tooth and a simple and easy method for manufacturing the zirconia sintered body. The method for manufacturing a zirconia sintered body includes a molding step of molding a powder composition that has an yttria content of more than 3% by mole and 5.2% by mole or less and that contains a first zirconia powder having an yttria content of 2% by mole or more and 4% by mole or less and a second zirconia powder having an yttria content of more than 4% by mole and 6% by mole or less to obtain a green body, and a sintering step of sintering the green body to obtain a sintered body.Type: ApplicationFiled: March 19, 2018Publication date: July 16, 2020Applicant: TOSOH CORPORATIONInventors: Kiyotaka KAWAMURA, Akiko ITO, Hiroyuki FUJISAKI, Sho AZECHI
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Patent number: 10555795Abstract: A zirconia sintered body is provided having a color tone equivalent to the color tone guides of various natural teeth and having the same aesthetics as a natural front tooth. The present invention provides a colored translucent zirconia sintered body comprising zirconia containing greater than 4.0 mol % and not greater than 6.5 mol % of yttria, less than 0.25 mol % of erbia, less than 2,000 ppm of iron oxide in terms of Fe2O3, less than 0.01 wt. % of cobalt oxide in terms of CoO, and less than 0.1 wt. % of alumina; the zirconia sintered body having a relative density of not less than 99.90%, a total light transmittance of not less than 25% and less than 40% for light having a wavelength of 600 nm at a sample thickness of 1.0 mm, and a strength of not less than 500 MPa.Type: GrantFiled: April 3, 2018Date of Patent: February 11, 2020Assignee: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura
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Publication number: 20180221120Abstract: A zirconia sintered body is provided having a color tone equivalent to the color tone guides of various natural teeth and having the same aesthetics as a natural front tooth. The present invention provides a colored translucent zirconia sintered body comprising zirconia containing greater than 4.0 mol % and not greater than 6.5 mol % of yttria, less than 0.25 mol % of erbia, less than 2,000 ppm of iron oxide in terms of Fe2O3, less than 0.01 wt. % of cobalt oxide in terms of CoO, and less than 0.1 wt. % of alumina; the zirconia sintered body having a relative density of not less than 99.90%, a total light transmittance of not less than 25% and less than 40% for light having a wavelength of 600 nm at a sample thickness of 1.0 mm, and a strength of not less than 500 MPa.Type: ApplicationFiled: April 3, 2018Publication date: August 9, 2018Applicant: TOSOH CORPORATIONInventors: Hiroyuki FUJISAKI, Kiyotaka KAWAMURA
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Patent number: 9962247Abstract: A zirconia sintered body is provided having a color tone equivalent to the color tone guides of various natural teeth and having the same aesthetics as a natural front tooth. The present invention provides a colored translucent zirconia sintered body comprising zirconia containing greater than 4.0 mol % and not greater than 6.5 mol % of yttria, less than 0.25 mol % of erbia, less than 2,000 ppm of iron oxide in terms of Fe2O3, less than 0.01 wt. % of cobalt oxide in terms of CoO, and less than 0.1 wt. % of alumina; the zirconia sintered body having a relative density of not less than 99.90%, a total light transmittance of not less than 25% and less than 40% for light having a wavelength of 600 nm at a sample thickness of 1.0 mm, and a strength of not less than 500 MPa.Type: GrantFiled: June 22, 2015Date of Patent: May 8, 2018Assignee: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura
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Patent number: 9737383Abstract: To provide a zirconia sintered body having both excellent translucency and bending strength, specifically a zirconia sintered body having both translucency and strength suitable as a denture for front tooth, and a process for its production. A translucent zirconia sintered body containing more than 4.0 mol % and at most 6.5 mol % of yttria and less than 0.1 wt % of alumina, and having a relative density of at least 99.82%, a total light transmittance of at least 37% and less than 40% to light with a wavelength of 600 nm at a thickness of 1.0 mm, and a bending strength of at least 500 MPa, and a process for its production.Type: GrantFiled: December 19, 2014Date of Patent: August 22, 2017Assignee: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura
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Publication number: 20170143458Abstract: A zirconia sintered body is provided having a color tone equivalent to the color tone guides of various natural teeth and having the same aesthetics as a natural front tooth. The present invention provides a colored translucent zirconia sintered body comprising zirconia containing greater than 4.0 mol % and not greater than 6.5 mol % of yttria, less than 0.25 mol % of erbia, less than 2,000 ppm of iron oxide in terms of Fe2O3, less than 0.01 wt. % of cobalt oxide in terms of CoO, and less than 0.1 wt. % of alumina; the zirconia sintered body having a relative density of not less than 99.90%, a total light transmittance of not less than 25% and less than 40% for light having a wavelength of 600 nm at a sample thickness of 1.0 mm, and a strength of not less than 500 MPa.Type: ApplicationFiled: June 22, 2015Publication date: May 25, 2017Applicant: TOSOH CORPORATIONInventors: Hiroyuki FUJISAKI, Kiyotaka KAWAMURA
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Publication number: 20160310245Abstract: To provide a zirconia sintered body having both excellent translucency and bending strength, specifically a zirconia sintered body having both translucency and strength suitable as a denture for front tooth, and a process for its production. A translucent zirconia sintered body containing more than 4.0 mol % and at most 6.5 mol % of yttria and less than 0.1 wt % of alumina, and having a relative density of at least 99.82%, a total light transmittance of at least 37% and less than 40% to light with a wavelength of 600 nm at a thickness of 1.0 mm, and a bending strength of at least 500 MPa, and a process for its production.Type: ApplicationFiled: December 19, 2014Publication date: October 27, 2016Applicant: TOSOH CORPORATIONInventors: Hiroyuki FUJISAKI, Kiyotaka KAWAMURA
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Patent number: 9428422Abstract: A pink-colored zirconia sintered body has a high sintered body density and strength, and a colored translucency, which has a color tone similar to teeth and excellent translucency and has high aesthetic properties. A colored translucent zirconia sintered body includes from 2 to 4 mol % of yttria, from 0.02 to 0.8 mol % of Er2O3, at least 20 and less than 2,000 ppm, as calculated as Fe2O3, of an iron compound, at least 0.005 and less than 0.2 wt % of Al2O3 and the rest being zirconia, and having a lightness L* of from 55 to 75, a* of from 0 to 10 and b* of from 0 to 30 as chromatic parameters stipulated in JIS-Z8729, has a relative density of at least 99.80% and has a total light transmittance of at least 18% and at most 40% as measured at a sample thickness of 1 mm using a D65 light source.Type: GrantFiled: December 26, 2013Date of Patent: August 30, 2016Assignee: TOSOH CORPORATIONInventors: Kiyotaka Kawamura, Hiroyuki Fujisaki
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Patent number: 9309157Abstract: A subject of the invention relates to providing a powder for a translucent zirconia sintered body which is necessary for the production of a zirconia sintered body having a high sintered-body density and high strength and giving an excellent sense of translucency, without conducting any special sintering, such as HIP sintering. The invention relates to a technique for obtaining, through normal-pressure sintering, a translucent zirconia sintered body characterized by comprising zirconia which contains 2-4 mol % yttria as a stabilizer and has an alumina content of 0.2 wt % or lower, and by having a relative density of 99.8% or higher and a total light transmittance, as measured at a thickness of 1.0 mm, of 35% or higher. It is preferred that a powder containing 0-0.2 wt % alumina with a particle diameter of 0.01-0.5 ?m, having a BET specific surface area of 5-16 m2/g and an average particle diameter of 0.3-0.7 ?m, and having a rate of sintering shrinkage in normal-pressure sintering (??/?T; g/cm3·° C.) of 0.Type: GrantFiled: August 29, 2014Date of Patent: April 12, 2016Assignee: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura, Kohei Imai
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Patent number: 9249056Abstract: A zirconia sintered body having not only high strength but also excellent aesthetic properties. A colored translucent zirconia sintered body, characterized by containing an iron compound and from 2 to 4 mol % of yttria, showing a lightness L* of from 51 to 80 in L*a*b* color system, and having a relative density of at least 99.80%. The colored zirconia sintered body preferably has a total light transmittance of at least 20% as measured at a sample thickness of 1 mm and with a D65 light source. The colored translucent zirconia sintered body has aesthetic properties equivalent to those of natural teeth and is particularly suitable for a zirconia sintered body to be used for dental applications, and further, suitable for a mill blank such as an artificial tooth material or the like, and an orthodontic bracket.Type: GrantFiled: July 27, 2012Date of Patent: February 2, 2016Assignee: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura, Kohei Imai
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Publication number: 20150315086Abstract: A pink-colored zirconia sintered body has a high sintered body density and strength, and a colored translucency, which has a color tone similar to teeth and excellent translucency and has high aesthetic properties. A colored translucent zirconia sintered body includes from 2 to 4 mol % of yttria, from 0.02 to 0.8 mol % of Er2O3, at least 20 and less than 2,000 ppm, as calculated as Fe2O3, of an iron compound, at least 0.005 and less than 0.2 wt % of Al2O3 and the rest being zirconia, and having a lightness L* of from 55 to 75, a* of from 0 to 10 and b* of from 0 to 30 as chromatic parameters stipulated in JIS-Z8729, has a relative density of at least 99.80% and has a total light transmittance of at least 18% and at most 40% as measured at a sample thickness of 1 mm using a D65 light source.Type: ApplicationFiled: December 26, 2013Publication date: November 5, 2015Applicant: TOSOH CORPORATIONInventors: Kiyotaka KAWAMURA, Hiroyuki FUJISAKI
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Publication number: 20140370453Abstract: A subject of the invention relates to providing a powder for a translucent zirconia sintered body which is necessary for the production of a zirconia sintered body having a high sintered-body density and high strength and giving an excellent sense of translucency, without conducting any special sintering, such as HIP sintering. The invention relates to a technique for obtaining, through normal-pressure sintering, a translucent zirconia sintered body characterized by comprising zirconia which contains 2-4 mol % yttria as a stabilizer and has an alumina content of 0.2 wt % or lower, and by having a relative density of 99.8% or higher and a total light transmittance, as measured at a thickness of 1.0 mm, of 35% or higher. It is preferred that a powder containing 0-0.2 wt % alumina with a particle diameter of 0.01-0.5 ?m, having a BET specific surface area of 5-16 m2/g and an average particle diameter of 0.3-0.7 ?m, and having a rate of sintering shrinkage in normal-pressure sintering (??/?T; g/cm3·° C.) of 0.Type: ApplicationFiled: August 29, 2014Publication date: December 18, 2014Applicant: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura, Kohei Imai
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Publication number: 20140227654Abstract: A zirconia sintered body having not only high strength but also excellent aesthetic properties. A colored translucent zirconia sintered body, characterized by containing an iron compound and from 2 to 4 mol % of yttria, showing a lightness L* of from 51 to 80 in L*a*b* color system, and having a relative density of at least 99.80%. The colored zirconia sintered body preferably has a total light transmittance of at least 20% as measured at a sample thickness of 1 mm and with a D65 light source. The colored translucent zirconia sintered body has aesthetic properties equivalent to those of natural teeth and is particularly suitable for a zirconia sintered body to be used for dental applications, and further, suitable for a mill blank such as an artificial tooth material or the like, and an orthodontic bracket.Type: ApplicationFiled: July 27, 2012Publication date: August 14, 2014Applicant: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura, Kohei Imai
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Publication number: 20110027742Abstract: A subject of the invention relates to providing a powder for a translucent zirconia sintered body which is necessary for the production of a zirconia sintered body having a high sintered-body density and high strength and giving an excellent sense of translucency, without conducting any special sintering, such as HIP sintering. The invention relates to a technique for obtaining, through normal-pressure sintering, a translucent zirconia sintered body characterized by comprising zirconia which contains 2-4 mol % yttria as a stabilizer and has an alumina content of 0.2 wt % or lower, and by having a relative density of 99.8% or higher and a total light transmittance, as measured at a thickness of 1.0 mm, of 35% or higher. It is preferred that a powder containing 0-0.2 wt % alumina with a particle diameter of 0.01-0.5 ?m, having a BET specific surface area of 5-16 m2/g and an average particle diameter of 0.3-0.7 ?m, and having a rate of sintering shrinkage in normal-pressure sintering (??/?T; g/cm3·° C.) of 0.Type: ApplicationFiled: April 8, 2009Publication date: February 3, 2011Applicant: TOSOH CORPORATIONInventors: Hiroyuki Fujisaki, Kiyotaka Kawamura, Kohei Imai
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Patent number: 6800973Abstract: There is disclosed an electric motor, which contains a plurality of windings wound around a stator core and a plurality of winding terminal receiving portions for containing that include terminal portions of the plurality of windings in a peripheral direction of the stator core at an interval. In addition, the motor includes a terminal plate with lead wires that are drawn out of the plurality of windings along the peripheral direction of the stator core, and connection fittings for electrically connecting the winding terminals to the corresponding lead wires.Type: GrantFiled: July 9, 2002Date of Patent: October 5, 2004Assignee: Toshiba Carrier CorporationInventors: Toshihiko Futami, Yoshiaki Inaba, Kiyotaka Kawamura
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Patent number: 6595760Abstract: A compressor including a compressing mechanical unit which inhales a refrigerant excluding chlorine, compresses the refrigerant, exhales the compressed refrigerant, and collects a refrigerating machine oil O compatible with the refrigerant, thereby lubricating the compressing mechanical unit with the refrigerating machine oil O. The compressor further includes an electric motor unit for driving the compressing mechanical unit. The electric motor unit includes a stator and a rotor, and is driven by an inverter. The stator includes three-phase wires and a stator core, wherein the stator core includes a yoke section and teeth sections on which the three-phase wires are wound, and the wires are wound on the teeth sections such that the wires on adjacent teeth sections have different phases.Type: GrantFiled: April 9, 1998Date of Patent: July 22, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Yoshiharu Shida, Yoshiaki Inaba, Kiyotaka Kawamura