Patents by Inventor Takahiko Homma
Takahiko Homma 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: 7470390Abstract: To provide a production method of a polycrystalline ceramic body with excellent density, a preparation step, a mixing step, a forming step and a heat-treating step are performed. In the preparation step, a coarse particle ceramic powder, and a fine particle powder having an average particle diameter of ? or less of the average particle diameter of the coarse particle ceramic powder are prepared. In the mixing step, the coarse particle ceramic powder and the fine particle powder are mixed to produce a raw material mixture. In the forming step, the raw material mixture is formed to a shaped body. In the heat-treating step, the shaped body is heated and thereby sintered to produce a polycrystalline ceramic body. In the heat-treating step, a temperature elevating process and a first holding process are performed and at the same time, a second holding process and/or a cooling process are performed.Type: GrantFiled: October 25, 2005Date of Patent: December 30, 2008Assignee: Denso CorporationInventors: Masaya Nakamura, Toshiatsu Nagaya, Tatsuhiko Nonoyama, Hisaaki Takao, Yasuyoshi Saito, Takahiko Homma, Kazumasa Takatori
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Patent number: 7443085Abstract: A piezoelectric actuator 1 includes a piezoelectric element 2, which has a pair of electrodes formed on the surface of a piezoelectric ceramic member, as a drive source. The piezoelectric actuator 1 satisfies at least one of the following requirements (a) to (c): (a) the variation width WC in an apparent dynamic capacity C [F] due to a change in temperature should fall within ±11% over a specific temperature range from ?30° C. to 80° C.; (b) the variation width WL in a displacement L [?m] due to a change in temperature should fall within ±14% over the specific temperature range from ?30° C. to 80° C.; and (c) the variation width WL/C in a quotient L/C due to a change in temperature should fall within ±12% over the specific temperature range from ?30° C. to 80° C., wherein C [F] denotes the apparent dynamic capacity and L [?m] denotes the displacement.Type: GrantFiled: March 13, 2007Date of Patent: October 28, 2008Assignee: Denso CorporationInventors: Toshiatsu Nagaya, Tatsuhiko Nonoyama, Masaya Nakamura, Yasuyoshi Saito, Hisaaki Takao, Takahiko Homma, Kazumasa Takatori
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Patent number: 7352113Abstract: The piezoelectric actuator includes a piezoelectric element (2) including a sheet of piezoelectric ceramic and electrodes formed at least part of the surface of the sheet of piezoelectric ceramic, and a holding member (4) holding the piezoelectric element (2); The piezoelectric at least one of the requirements (a) to (e) described below; (a) The bulk density shall be equal to or smaller than 5 g/cm3, and the Young's modulus Y11E calculated according to a resonance-antiresonance method shall be equal to or larger than 90 GPa; (b) The coefficient of thermal conductivity shall be equal to or larger than 2 Wm?1K?1; (c) The coefficient of thermal expansion shall be equal to or larger than 3.0 ppm/° C. over a temperature range from ?30° C. to 160° C.; (d) The pyroelectric coefficient shall be equal to or smaller than 400 ?Cm?2K?1 over the temperature range from ?30° C. to 160° C.Type: GrantFiled: March 13, 2007Date of Patent: April 1, 2008Assignee: DENSO CorporationInventors: Toshiatsu Nagaya, Tatsuhiko Nonoyama, Masaya Nakamura, Yasuyoshi Saito, Hisaaki Takao, Takahiko Homma, Kazumasa Takatori
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Publication number: 20070228874Abstract: A piezoelectric actuator 1 includes a piezoelectric element 2, which has a pair of electrodes formed on the surface of a piezoelectric ceramic member, as a drive source. The piezoelectric actuator 1 satisfies at least one of the following requirements (a) to (c): (a) the variation width WC in an apparent dynamic capacity C [F] due to a change in temperature should fall within ±11% over a specific temperature range from ?30° C. to 80° C.; (b) the variation width WL in a displacement L [?m] due to a change in temperature should fall within ±14% over the specific temperature range from ?30° C. to 80° C.; and (c) the variation width WL/C in a quotient L/C due to a change in temperature should fall within ±12% over the specific temperature range from ?30° C. to 80° C., wherein C [F] denotes the apparent dynamic capacity and L [?m] denotes the displacement.Type: ApplicationFiled: March 13, 2007Publication date: October 4, 2007Applicant: DENSO CorporationInventors: Toshiatsu Nagaya, Tatsuhiko Nonoyama, Masaya Nakamura, Yasuyoshi Saito, Hisaaki Takao, Takahiko Homma, Kazumasa Takatori
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Patent number: 7267783Abstract: This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and is excellent in at least one of a piezoelectric constant, an electro-mechanical coupling coefficient, a dielectric loss, a relative dielectric constant and a Curie point, its production method, and a piezoelectric device and a dielectric device each utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition expressed by the general formula {Lix(K1?yNay)1?x}(Nb1?zSbz)O3, each of x, y and z respectively falling within composition ranges of 0?x?0.2, 0?y?1.0 and 0?z?0.2 (with the exception of x=z=0), and its production method. The invention further relates to a piezoelectric device having a piezoelectric body formed of the piezoelectric ceramic composition described above and a dielectric device having a dielectric body formed of the piezoelectric ceramic composition described above.Type: GrantFiled: March 19, 2003Date of Patent: September 11, 2007Assignee: DENSO CORPORATIONInventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Takahiko Homma, Hisaaki Takao
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Publication number: 20070176516Abstract: A piezoelectric sensor capable of preventing fluctuation in the sensitivity of the piezoelectric sensor over a wide temperature range is provided. This is a piezoelectric sensor comprising a piezoelectric element and a holding member for holding the piezoelectric element, the piezoelectric element comprising a piezoelectric ceramic having formed on the surfaces thereof a pair of electrodes. The piezoelectric ceramic satisfies the following requirement (a) and/or requirement (b): (a) in the temperature range from ?30° C. to 160° C., the thermal expansion coefficient is 3.0 ppm/° C. or more, and (b) in the temperature range from ?30° C. to 160° C., the pyroelectric coefficient is 400 ?Cm?2K?1 or less.Type: ApplicationFiled: March 8, 2007Publication date: August 2, 2007Applicant: Denso CorporationInventors: Toshiatsu Nagaya, Tatsuhiko Nonoyama, Masaya Nakamura, Yasuyoshi Saito, Hisaaki Takao, Takahiko Homma, Kazumasa Takatori
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Publication number: 20070159028Abstract: The present invention provides a piezoelectric actuator that enjoys excellent practicality. The piezoelectric actuator includes a piezoelectric element (2) including a sheet of piezoelectric ceramic and electrodes formed at least part of the surface of the sheet of piezoelectric ceramic, and a holding member (4) holding the piezoelectric element (2). The piezoelectric at least one of the requirements (a) to (e) described below. (a) The bulk density shall be equal to or smaller than 5 g/cm3, and the Young's modulus Y11E calculated according to a resonance-antiresonance method shall be equal to or larger than 90 GPa. (b) The coefficient of thermal conductivity shall be equal to or larger than 2 Wm?1K?1. (c) The coefficient of thermal expansion shall be equal to or larger than 3.0 ppm/° C. over a temperature range from ?30° C. to 160° C. (d) The pyroelectric coefficient shall be equal to or smaller than 400 ?Cm?2K?1 over the temperature range from ?30° C. to 160° C.Type: ApplicationFiled: March 13, 2007Publication date: July 12, 2007Applicant: DENSO CORPORATIONInventors: Toshiatsu Nagaya, Tatsuhiko Nonoyama, Masaya Nakamura, Yasuyoshi Saito, Hisaaki Takao, Takahiko Homma, Kazumasa Takatori
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Patent number: 7150838Abstract: This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and has a high electro-mechanical coupling coefficient and a small dielectric loss, its production method, and a piezoelectric device utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition containing a compound expressed by the general formula {Lix(K1-yNay)1-x}(Nb1-zTaz)O3, each of x, y and z respectively falling within composition range of 0?x?0.2, 0?y?1.0 and 0?z?0.4, as its main component, and further containing nickel or a nickel-containing compound. To provide a piezoelectric device that does not contain lead, can be sintered at a normal pressure and has a high electro-mechanical coupling coefficient Kp and a small dielectric loss, the piezoelectric ceramic composition of the invention is expressed by the general formula {Lix(K1-yNay)1-x}(Nb1-z-nTaz(Mn0.5W0.Type: GrantFiled: March 19, 2003Date of Patent: December 19, 2006Assignee: Denso CorporationInventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Hisaaki Takao, Takahiko Homma
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Patent number: 7101491Abstract: A piezoelectric ceramic composition not containing lead, able to be sintered at ordinary pressure, and superior to the past in at least one of the properties unique to piezoelectric ceramic compositions such as the piezoelectric d31 constant, that is, a piezoelectric ceramic composition having a compound of a general formula {Lix(K1-yNay)1-x}(Nb1-z-wTazSbw)O3 where x, y, z, and w are in the ranges of 0?x?0.2, 0?y?1, 0<z?0.4, and 0<w?0.2 as a main ingredient, where the piezoelectric ceramic composition contains at least one metal element selected from (1) palladium, silver, gold, ruthenium, rhodium, rhenium, osmium, iridium, and platinum, (2) nickel, iron, manganese, copper, and zinc, or (3) magnesium, calcium, strontium, and barium as an added element, and a method of production of the same and a piezoelectric element and dielectric element utilizing that piezoelectric ceramic composition.Type: GrantFiled: July 16, 2003Date of Patent: September 5, 2006Assignees: DENSO Corporation, Kabushiki Kaisha Toyota Chuo KenkyushoInventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Hisaaki Takao, Takahiko Homma
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Patent number: 7059203Abstract: A physical sensor having a pressure sensing layer having such property that electrical resistance is changed by application of a stress, and electrical insulating layers which are integrally formed on opposite two surfaces of the pressure sensing layer, respectively, wherein the pressure sensing layer has a matrix comprising glass, and an electrically conductive particle having electrical conductivity and dispersed in the matrix and preferably, the electrically conductive particle includes RuO2, and a thickness of the pressure sensing layer is 1 ?m to 200 ?m, and it is preferable that one pair of electrodes are disposed on the pressure sensing layer.Type: GrantFiled: November 16, 2004Date of Patent: June 13, 2006Assignee: Kabushiki Kaisha Toyota Chuo KenkyushoInventors: Mitsuru Asai, Hiroaki Makino, Takahiko Homma, Kazumasa Takatori, Jun Sugiyama
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Publication number: 20060091588Abstract: To provide a production method of a polycrystalline ceramic body with excellent density, a preparation step, a mixing step, a forming step and a heat-treating step are performed. In the preparation step, a coarse particle ceramic powder, and a fine particle powder having an average particle diameter of ? or less of the average particle diameter of the coarse particle ceramic powder are prepared. In the mixing step, the coarse particle ceramic powder and the fine particle powder are mixed to produce a raw material mixture. In the forming step, the raw material mixture is formed to a shaped body. In the heat-treating step, the shaped body is heated and thereby sintered to produce a polycrystalline ceramic body. In the heat-treating step, a temperature elevating process and a first holding process are performed and at the same time, a second holding process and/or a cooling process are performed.Type: ApplicationFiled: October 25, 2005Publication date: May 4, 2006Applicant: DENSO CorporationInventors: Masaya Nakamura, Toshiatsu Nagaya, Tatsuhiko Nonoyama, Hisaaki Takao, Yasuyoshi Saito, Takahiko Homma, Kazumasa Takatori
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Publication number: 20060006360Abstract: To provide a grain oriented ceramic capable of exerting excellent piezoelectric properties, a production method thereof, and a piezoelectric material, a dielectric material, a thermoelectric conversion element and an ion conducting element each using the grain oriented ceramic, there is provided a grain oriented ceramic comprising, as the main phase, an isotropic perovskite-type compound which is represented by formula (1): {Lix(K1?yNay)1?x}(Nb1?z?wTazSbw)O3 in which x, y, z and w are in respective composition ranges of 0?x?0.2, 0?y?1, 0?z?0.4, 0?w?0.2 and x+z+w>0. The main phase comprises a polycrystalline body containing from 0.0001 to 0.15 mol of any one or more additional element selected from metal elements, semimetal elements, transition metal elements, noble metal elements and alkaline earth metal elements belonging to Groups 2 to 15 of the Periodic Table, per mol of the compound represented by formula (1).Type: ApplicationFiled: June 17, 2005Publication date: January 12, 2006Applicant: DENSO CorporationInventors: Hisaaki Takao, Takahiko Homma, Yasuyoshi Saito, Kazumasa Takatori, Tatsuhiko Nonoyama, Toshiatsu Nagaya, Masaya Nakamura
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Publication number: 20050103124Abstract: A physical sensor having a pressure sensing layer having such property that electrical resistance is changed by application of a stress, and electrical insulating layers which are integrally formed on opposite two surfaces of the pressure sensing layer, respectively. The pressure sensing layer comprises a matrix comprising glass, and an electrically conductive particle having electrical conductivity and dispersed in the matrix. Preferably, the electrically conductive particle comprises RuO2, and a thickness of the pressure sensing layer is 1 ?m to 200 ?m. It is preferable that one pair of electrodes are disposed on the pressure sensing layer.Type: ApplicationFiled: November 16, 2004Publication date: May 19, 2005Applicant: KABUSHIKI KAISHA TOYOTA CHUO KENKYUSHOInventors: Mitsuru Asai, Hiroaki Makino, Takahiko Homma, Kazumasa Takatori, Jun Sugiyama
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Publication number: 20040214723Abstract: The present invention provides crystal oriented ceramics, and a production method of the same, having a basic composition of isotropic perovskite-based potassium sodium niobate, demonstrating superior piezoelectric characteristics, and having a specific crystal plane oriented to a high degree of orientation. The crystal oriented ceramics as claimed in the present invention is composed of a polycrystalline substance of an isotropic perovskite compound represented by the general formula: {Lix(K1−yNay)1−x}{Nb1−z−wTazSbw}O3 (wherein, 0≦x≦0.2, 0≦y≦1, 0≦z≦0.4, 0≦w≦0.2, x+z+w>0), and a specific crystal plane of each crystal grain that composes said polycrystalline substance is oriented.Type: ApplicationFiled: March 15, 2004Publication date: October 28, 2004Applicant: DENSO CORPORATIONInventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Hisaaki Takao, Takahiko Homma, Yasuyoshi Saito, Kazumasa Takatori, Masaya Nakamura
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Publication number: 20040058797Abstract: A piezoelectric ceramic composition not containing lead, able to be sintered at ordinary pressure, and superior to the past in at least one of the properties unique to piezoelectric ceramic compositions such as the piezoelectric d31 constant, that is, a piezoelectric ceramic composition having a compound of a general formula {Lix(K1-yNay)1-x}(Nb1−z−wTazSbw)O3 where x, y, z, and w are in the ranges of 0≦x≦0.2, 0≦y≦1, 0<z≦0.4, and 0<w≦0.2 as a main ingredient, where the piezoelectric ceramic composition contains at least one metal element selected from (1) palladium, silver, gold, ruthenium, rhodium, rhenium, osmium, iridium, and platinum, (2) nickel, iron, manganese, copper, and zinc, or (3) magnesium, calcium, strontium, and barium as an added element, and a method of production of the same and a piezoelectric element and dielectric element utilizing that piezoelectric ceramic composition.Type: ApplicationFiled: July 16, 2003Publication date: March 25, 2004Inventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Hisaaki Takao, Takahiko Homma
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Publication number: 20030178605Abstract: This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and is excellent in at least one of a piezoelectric constant, an electromechanical coupling coefficient, a dielectric loss, a relative dielectric constant and a Curie point, its production method, and a piezoelectric device and a dielectric device each utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition expressed by the general formula {Lix(K1-yNay)1-x}(Nb1-zSbz)O3, each of x, y and z respectively falling within composition ranges of 0≦x≦0.2, 0≦y≦1.0 and 0≦z≦0.2 (with the exception of x=z=0), and its production method. The invention further relates to a piezoelectric device having a piezoelectric body formed of the piezoelectric ceramic composition described above and a dielectric device having a dielectric body formed of the piezoelectric ceramic composition described above.Type: ApplicationFiled: March 19, 2003Publication date: September 25, 2003Inventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Takahiko Homma, Hisaaki Takao
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Publication number: 20030178606Abstract: This invention provides a piezoelectric ceramic composition that does not contain lead, can be sintered at a normal pressure and has a high electromechanical coupling coefficient and a small dielectric loss, its production method, and a piezoelectric device utilizing the piezoelectric ceramic composition. The invention relates to a piezoelectric composition containing a compound expressed by the general formula {Lix(K1-yNay)1-x}(Nb1-zTaz)O3, each of x, y and z respectively falling within composition range of 0≦x≦0.2, 0≦y≦1.0 and 0≦z≦0.4, as its main component, and further containing nickel or a nickel-containing compound. To provide a piezoelectric device that does not contain lead, can be sintered at a normal pressure and has a high electromechanical coupling coefficient Kp and a small dielectric loss, the piezoelectric ceramic composition of the invention is expressed by the general formula {Lix(K1-yNay)1-x}(Nb1-z-nTaz(Mn0.5W0.Type: ApplicationFiled: March 19, 2003Publication date: September 25, 2003Inventors: Tatsuhiko Nonoyama, Toshiatsu Nagaya, Yasuyoshi Saito, Kazumasa Takatori, Hisaaki Takao, Takahiko Homma
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Patent number: 4692099Abstract: A rotary component of a rotary device for heat engines, such as a turbine wheel of a gas turbine or a turbocharger, formed in an integral ceramic-fiber-reinforced sintered ceramic structure. The reinforcing ceramic fibers in the edges of the vanes of the rotary component are oriented radially to prevent the chipping of the edges of the vanes liable to occur in a direction perpendicular to the direction of thickness of the vanes. The rotary component is formed by molding a mixture of a ceramic powder, ceramic fibers and organic additive or additives in a mold having a cavity having the same shape as that of the rotary component except that the depth of sections of the cavity corresponding to the vanes is greater than the height of the vanes to be formed, sintering the molding, and cutting the vanes of the molding in a predetermined height.Type: GrantFiled: June 17, 1986Date of Patent: September 8, 1987Assignee: Kabushiki Kaisha Toyota Chuo KenkyushoInventors: Takahiko Homma, Shigetaka Wada