Patents by Inventor Kei Kamada

Kei Kamada 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).

  • Patent number: 11158784
    Abstract: The present invention makes clear and defines a congruent composition of a langasite-based oxide, and establishes a method of manufacturing a crystal by any desired composition of AE3ME1+a(Ga1?xAlx)3+bSi2+cO14 (AE is an alkaline-earth metal, ME is Nb or Ta, 0?x?1, ?0.5<a?0 or 0<a<0.5, ?0.5<b?0 or 0<b?0.5, and ?0.5<c?0 or 0<c<0.5, excluding a=b=c=0). This makes it possible to suppress the formation of an impurity, and improve the yield and crystal manufacturing rate. The raw material is a raw material mixture prepared by mixing an alkaline-earth metal or its carbonate or oxide, Nb or Ta or its oxide, Ga or its oxide, Al or its oxide, and Si or its oxide.
    Type: Grant
    Filed: February 24, 2017
    Date of Patent: October 26, 2021
    Assignees: PIEZO STUDIO INC., TOHOKU UNIVERSITY
    Inventors: Akira Yoshikawa, Yuui Yokota, Yuji Ohashi, Kei Kamada, Tetsuo Kudo, Kenji Inoue, Yasuhiro Shoji, Yu Igarashi, Mototaka Arakawa, Shunsuke Kurosawa, Akihiro Yamaji
  • Publication number: 20210277504
    Abstract: A metal member according to this invention is composed of polycrystals of a metal made of ruthenium or an alloy containing ruthenium at a maximum ratio. The aspect ratio of a crystal grain of the polycrystalline metal member is 1.5 or more. A plurality of crystal grains forming the metal member are arranged with their major axes being pointed in the same direction, and the number of crystal grains in a section in the major axis direction of the crystal grains is 120 or less per 1 mm2.
    Type: Application
    Filed: June 27, 2018
    Publication date: September 9, 2021
    Inventors: Akira YOSHIKAWA, Rikito MURAKAMI, Yui YOKOTA, Takayuki NIHEI, Kei KAMADA, Yasuhiro SHOJI, Shunsuke KUROSAWA, Akihiro YAMAJI, Yuji OHASHI
  • Patent number: 11031539
    Abstract: To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece (101) is made of a Ca3Ta(Ga1-xAlx)3Si2O14 single crystal (0<x?1). In the single crystal, letting ? be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5???24x+24.5 is set. In addition, the vibrating piece (101) is made of a Ca3Nb(Ga1-xAlx)3Si2O14 single crystal (0<x?1). In the single crystal of this arrangement, letting ? be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083???32x+26.167 is set.
    Type: Grant
    Filed: November 4, 2016
    Date of Patent: June 8, 2021
    Assignees: PIEZO STUDIO INC., TOHOKU UNIVERSITY
    Inventors: Akira Yoshikawa, Yuji Ohashi, Yuui Yokota, Kei Kamada, Masatoshi Ito, Kenji Inoue, Hiroyuki Amano
  • Patent number: 10771032
    Abstract: To improve the Q value of a piezoelectric thin-film element in a state in which unnecessary vibration is suppressed, an acoustic reflection film (104) is affixed to a first electrode (102), a piezoelectric single-crystal substrate (101) is thinned by polishing from the other surface (101b) of the piezoelectric single-crystal substrate (101), such that the first electrode (102) and piezoelectric thin film (105) are piled on the piezoelectric single-crystal substrate (101). In this polishing, a pressure (polishing pressure) to the surface (101b) during polishing in an electrode formation region where the first electrode (102) is formed differs from that in a non-electrode formation region around the electrode formation region. Consequently, the electrode formation region of the piezoelectric thin film (105), where the first electrode (102) is formed, is made thinner than the non-electrode formation region around the electrode formation region.
    Type: Grant
    Filed: July 25, 2016
    Date of Patent: September 8, 2020
    Assignees: PIEZO STUDIO INC., TOHOKU UNIVERSITY
    Inventors: Kenji Inoue, Akira Yoshikawa, Yuji Ohashi, Yuui Yokota, Kei Kamada, Shunsuke Kurosawa
  • Publication number: 20190140160
    Abstract: The present invention makes clear and defines a congruent composition of a langasite-based oxide, and establishes a method of manufacturing a crystal by any desired composition of AE3ME1+a(Ga1-xAlx)3+bSi2+cO14 (AE is an alkaline-earth metal, ME is Nb or Ta, 0?x?1, ?0.5<a?0 or 0<a<0.5, ?0.5<b?0 or 0<b?0.5, and ?0.5<c?0 or 0<c<0.5, excluding a=b=c=0). This makes it possible to suppress the formation of an impurity, and improve the yield and crystal manufacturing rate. The raw material is a raw material mixture prepared by mixing an alkaline-earth metal or its carbonate or oxide, Nb or Ta or its oxide, Ga or its oxide, Al or its oxide, and Si or its oxide.
    Type: Application
    Filed: February 24, 2017
    Publication date: May 9, 2019
    Inventors: Akira YOSHIKAWA, Yuui YOKOTA, Yuji OHASHI, Kei KAMADA, Tetsuo KUDO, Kenji INOUE, Yasuhiro SHOJI, Yu IGARASHI, Mototaka ARAKAWA, Shunsuke KUROSAWA, Akihiro YAMAJI
  • Patent number: 10174247
    Abstract: An illuminant has a short fluorescence lifetime, high transparency, and high light yield and a radiation detector uses the illuminant. The illuminant is appropriate for a radiation detector for detecting gamma-rays, X-rays, ?-rays, and neutron rays, and has high radiation resistance, a short fluorescence decay time and high emission intensity. The illuminant has a garnet structure using emission from the 4f5d level of Ce3+, and includes a garnet illuminant prepared by co-doping of at least one type of monovalent or divalent cation at a molar ratio of 7000 ppm or less with respect to all cations, to an illuminant having a garnet structure represented by general formula CexRE3?xM5+yO12+3y/2 (where 0.0001?x?0.3, 0?y?0.5 or 0?y??0.5, M is one type or two or more types selected from Al, Lu, Ga, and Sc, and RE is one type or two or more types selected from La, Pr, Gd, Tb, Yb, Y, and Lu).
    Type: Grant
    Filed: April 30, 2015
    Date of Patent: January 8, 2019
    Assignees: TOHOKU TECHNO ARCH CO., LTD., C & A CORPORATION
    Inventors: Kei Kamada, Akira Yoshikawa, Yuui Yokota, Shunsuke Kurosawa, Yasuhiro Shoji
  • Publication number: 20180323366
    Abstract: To provide a vibrator made of a piezoelectric crystal having a larger electromechanical coupling coefficient and a more satisfactory frequency-temperature characteristic than those of quartz, a vibrating piece (101) is made of a Ca3Ta(Ga1-xAlx)3Si2O14 single crystal (0<x?1). In the single crystal, letting ? be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 18x+17.5???24x+24.5 is set. In addition, the vibrating piece (101) is made of a Ca3Nb(Ga1-xAlx)3Si2O14 single crystal (0<x?1). In the single crystal of this arrangement, letting ? be a rotation angle from an X-Z plane about an X-axis serving as a rotation axis, 25x+23.083???32x+26.167 is set.
    Type: Application
    Filed: November 4, 2016
    Publication date: November 8, 2018
    Applicants: PIEZO STUDIO INC., TOHOKU UNIVERSITY
    Inventors: Akira YOSHIKAWA, Yuji OHASHI, Yuui YOKOTA, Kei KAMADA, Masatoshi ITO, Kenji INOUE, Hiroyuki AMANO
  • Publication number: 20180226939
    Abstract: To improve the Q value of a piezoelectric thin-film element in a state in which unnecessary vibration is suppressed, an acoustic reflection film (104) is affixed to a first electrode (102), a piezoelectric single-crystal substrate (101) is thinned by polishing from the other surface (101b) of the piezoelectric single-crystal substrate (101), such that the first electrode (102) and piezoelectric thin film (105) are piled on the piezoelectric single-crystal substrate (101). In this polishing, a pressure (polishing pressure) to the surface (101b) during polishing in an electrode formation region where the first electrode (102) is formed differs from that in a non-electrode formation region around the electrode formation region. Consequently, the electrode formation region of the piezoelectric thin film (105), where the first electrode (102) is formed, is made thinner than the non-electrode formation region around the electrode formation region.
    Type: Application
    Filed: July 25, 2016
    Publication date: August 9, 2018
    Inventors: Kenji INOUE, Akira YOSHIKAWA, Yuji OHASHI, Yuui YOKOTA, Kei KAMADA, Shunsuke KUROSAWA
  • Patent number: 10011770
    Abstract: A crystal material that is represented by a general formula (1): (RExA1-x-y-sByM?s)2+?(Si1-t,M?t)2+?O7+? (1), the crystal material having a pyrochlore type structure, being a nonstoichiometric composition, and being a congruent melting composition, wherein in Formula (1), A contains at least one or more selected from Gd, Y, La, Sc, Yb, and Lu; B contains at least one or more selected from La, Gd, Yb, Lu, Y, and Sc; 0.1?y<0.4; RE contains at least one or more selected from Ce, Pr, Nd, Eu, Tb, and Yb; 0<x<0.1; M? and M? contain at least one or more selected from Li, Na, K, Mg, Ca, Sr, Ba, Ti, Zr, Hf, Fe, Ta, and W; 0?s<0.01 and 0?t<0.01; and 0<|?|<0.3 and 0?|?|<0.3 and 0?|?|<0.5.
    Type: Grant
    Filed: May 27, 2016
    Date of Patent: July 3, 2018
    Assignees: TOHOKU UNIVERSITY, C&A CORPORATION
    Inventors: Shunsuke Kurosawa, Akira Yoshikawa, Kei Kamada, Yuui Yokota, Yuji Ohashi, Takahiko Horiai, Yasuhiro Shoji, Rikito Murakami
  • Publication number: 20180100101
    Abstract: A crystal material that is represented by a general formula (1): (RExA1-x-y-sByM?s)2+?(Si1-t?M?t)2+?O7+? (1), the crystal material having a pyrochlore type structure, being a nonstoichiometric composition, and being a congruent melting composition, wherein in Formula (1), A contains at least one or more selected from Gd, Y, La, Sc, Yb, and Lu; B contains at least one or more selected from La, Gd, Yb, Lu, Y, and Sc; 0.1?y<0.4; RE contains at least one or more selected from Ce, Pr, Nd, Eu, Tb, and Yb; 0<x<0.1; M? and M? contain at least one or more selected from Li, Na, K, Mg, Ca, Sr, Ba, Ti, Zr, Hf, Fe, Ta, and W; 0?s<0.01 and 0?t<0.01; and 0<|?|<0.3 and 0?|?|<0.3 and 0?|?|<0.5.
    Type: Application
    Filed: May 27, 2016
    Publication date: April 12, 2018
    Inventors: Shunsuke KUROSAWA, Akira YOSHIKAWA, Kei KAMADA, Yuui YOKOTA, Yuji OHASHI, Takahiko HORIAI, Yasuhiro SHOJI, Rikito MURAKAMI
  • Patent number: 9834858
    Abstract: The present invention provides an oxide-base scintillator single crystal having an extremely large energy of light emission, adoptable to X-ray CT and radioactive ray transmission inspection apparatus, and more specifically to provide a Pr-containing, garnet-type oxide single crystal, a Pr-containing perovskite-type oxide single crystal, and a Pr-containing silicate oxide single crystal allowing detection therefrom light emission supposedly ascribable to 5d-4f transition of Pr.
    Type: Grant
    Filed: November 7, 2005
    Date of Patent: December 5, 2017
    Assignees: TOHOKU TECHNO ARCH CO., LTD., FURUKAWA CO., LTD.
    Inventors: Akira Yoshikawa, Hiraku Ogino, Kei Kamada, Kenji Aoki, Tsuguo Fukuda
  • Publication number: 20170044433
    Abstract: An illuminant has a short fluorescence lifetime, high transparency, and high light yield and a radiation detector uses the illuminant. The illuminant is appropriate for a radiation detector for detecting gamma-rays, X-rays, ?-rays, and neutron rays, and has high radiation resistance, a short fluorescence decay time and high emission intensity. The illuminant has a garnet structure using emission from the 4f5d level of Ce3+, and includes a garnet illuminant prepared by co-doping of at least one type of monovalent or divalent cation at a molar ratio of 7000 ppm or less with respect to all cations, to an illuminant having a garnet structure represented by general formula CexRE3?xM5+yO12+3y/2 (where 0.0001?x?0.3, 0?y?0.5 or 0?y??0.5, M is one type or two or more types selected from Al, Lu, Ga, and Sc, and RE is one type or two or more types selected from La, Pr, Gd, Tb, Yb, Y, and Lu).
    Type: Application
    Filed: April 30, 2015
    Publication date: February 16, 2017
    Applicants: TOHOKU TECHNO ARCH CO., LTD., C & A CORPORATION
    Inventors: Kei KAMADA, Akira YOSHIKAWA, Yuui YOKOTA, Shunsuke KUROSAWA, Yasuhiro SHOJI
  • Patent number: 8969812
    Abstract: The garnet-type crystal for a scintillator of the present invention is represented by General Formula (1), (2), or (3), Gd3-x-yCexREyAl5-zGazO12??(1) wherein in Formula (1), 0.0001?x?0.15, 0?y?0.1, 2<z?4.5, and RE represents at least one selected from Y, Yb, and Lu; Gd3-a-bCeaLubAl5-cGacO12??(2) wherein in Formula (2), 0.0001?a?0.15, 0.1<b?3, and 2<c?4.5; Gd3-p-qCerRE?qAl5-rGarO12??(3) wherein in Formula (3), 0.0001?p?0.15, 0.1<q?3, 1<r?4.5, and RE? represents Y or Yb.
    Type: Grant
    Filed: January 27, 2012
    Date of Patent: March 3, 2015
    Assignees: Furukawa Co., Ltd., Tohoku Techno Arch Co., Ltd.
    Inventors: Akira Yoshikawa, Takayuki Yanagida, Kei Kamada, Hiroki Sato, Kosuke Tsutsumi, Takanori Endo, Shigeki Ito
  • Publication number: 20150028218
    Abstract: A radiation detector (1) includes a three-dimensional stacked scintillator (12) that includes a plurality of scintillator blocks (13) arranged in a matrix in a three-dimensional manner so as to form a prism, in which interposed layers (15) which have a refractive index different from a refractive index of the scintillator blocks (13) and/or have a characteristic of absorbing or scattering some of light emitted by the scintillator blocks are disposed, out of boundary surfaces between the plurality of scintillator blocks (13), on the boundary surfaces extending in a direction perpendicular to a height direction H of the prism, and light blocking layers (14) which block transmission of light emitted by the scintillator are disposed on at least some of the boundary surfaces extending in a direction parallel to the height direction of the prism.
    Type: Application
    Filed: December 19, 2012
    Publication date: January 29, 2015
    Inventors: Jun Kataoka, Aya Kishimoto, Kei Kamada
  • Publication number: 20130306874
    Abstract: The garnet-type crystal for a scintillator of the present invention is represented by General Formula (1), (2), or (3), Gd3-x-yCexREyAl5-zGazO12??(1) wherein in Formula (1), 0.0001?x?0.15, 0?y?0.1, 2<z?4.5, and RE represents at least one selected from Y, Yb, and Lu; Gd3-a-bCeaLubAl5-cGacO12??(2) wherein in Formula (2), 0.0001?a?0.15, 0.1<b?3, and 2<c?4.5; Gd3-p-qCerRE?qAl5-rGarO12??(3) wherein in Formula (3), 0.0001?p?0.15, 0.1<q?3, 1<r?4.5, and RE? represents Y or Yb.
    Type: Application
    Filed: January 27, 2012
    Publication date: November 21, 2013
    Applicants: TOHOKU TECHNO ARCH CO., LTD., FURUKAWA CO., LTD.
    Inventors: Akira Yoshikawa, Takayuki Yanagida, Kei Kamada, Hiroki Sato, Kosuke Tsutsumi, Takanori Endo, Shigeki Ito
  • Patent number: 8445852
    Abstract: An electric signal produced by a photo-electric conversion element (104) is input to a comparator (120). The comparator (120) judges whether the electric signal output from the amplifier (110) exceeds a reference voltage or not, and outputs a HIGH signal if “exceeds”. A reference voltage modifier unit (130) elevates the reference voltage, after a predetermined time period elapses since the comparator (120) judged that the electric signal reached or exceeded the reference voltage. The signal processor calculates an incidence time which represents a time when the signal light starts to enter the photo-electric converter unit (100), by correcting a rise-up time of the electric signal when it reaches or exceeds the reference voltage, based on a pulse width which represents a time period from when the electric signal exceeds the reference voltage, up to when the electric signal falls below the reference voltage.
    Type: Grant
    Filed: June 11, 2010
    Date of Patent: May 21, 2013
    Assignees: The University of Tokyo, Furukawa Co., Ltd
    Inventors: Hiroyuki Takahashi, Yoshiyuki Usuki, Kei Kamada
  • Publication number: 20110215249
    Abstract: An electric signal produced by a photo-electric conversion element(104) is input to a comparator (120). The comparator (120) judges whether the electric signal output from the amplifier (110) exceeds a reference voltage or not, and outputs a HIGH signal if “exceeds”. A reference voltage modifier unit (130) elevates the reference voltage, after a predetermined time period elapses since the comparator (120) judged that the electric signal reached or exceeded the reference voltage. The signal processor calculates an incidence time which represents a time when the signal light starts to enter the photo-electric converter unit (100), by correcting a rise-up time of the electric signal when it reaches or exceeds the reference voltage, based on a pulse width which represents a time period from when the electric signal exceeds the reference voltage, up to when the electric signal falls below the reference voltage.
    Type: Application
    Filed: June 11, 2010
    Publication date: September 8, 2011
    Applicants: THE UNIVERSITY OF TOKYO, FURUKAWA CO., LTD.
    Inventors: Hiroyuki Takahashi, Yoshiyuki Usuki, Kei Kamada
  • Patent number: 7608828
    Abstract: A rare earth fluoride solid solution material (polycrystal and/or single crystal) characterized in that the material is obtained by mutually combining a plurality of rare earth fluorides having phase transitions and having different ion radii, respectively, so that the rare earth fluoride solid solution material is free of phase transitions. A rare earth fluoride solid solution material (polycrystal and/or single crystal) characterized in that the material is represented by (REyRE?1?y)F3 (0.0000<y<1.0000), wherein RE represents one or two or more selected from Sm, Eu, and Gd, and RE? represents one or two or more selected from Er, Tm, Yb, Lu, and Y. A rare earth fluoride solid solution material (polycrystal and/or single crystal) represented by MxREyRE?1?x?yFz., wherein RE is one or two or more selected from Ce, Pr, Nd, Eu, Tb, Ho, Er, Tm, or Yb, RE? is one or two or more selected from La, Sm, Gd, Dy, Lu, Y, and Sc, and M is one or more of Mg, Ca, Sr, and Ba.
    Type: Grant
    Filed: April 12, 2005
    Date of Patent: October 27, 2009
    Assignees: Stella Chemifa Corporation, Tohoku Techno Arch Co., Ltd.
    Inventors: Akira Yoshikawa, Kenji Aoki, Tomohiko Satonaga, Kei Kamada, Tsuguo Fukuda
  • Publication number: 20080213151
    Abstract: The present invention provides an oxide-base scintillator single crystal having an extremely large energy of light emission, adoptable to X-ray CT and radioactive ray transmission inspection apparatus, and more specifically to provide a Pr-containing, garnet-type oxide single crystal, a Pr-containing perovskite-type oxide single crystal, and a Pr-containing silicate oxide single crystal allowing detection therefrom light emission supposedly ascribable to 5d-4f transition of Pr.
    Type: Application
    Filed: November 7, 2005
    Publication date: September 4, 2008
    Applicants: TOHOKU TECHNO ARCH CO., LTD, FURUKAWA CO., LTD
    Inventors: Akira Yoshikawa, Hiraku Ogino, Kei Kamada, Kenji Aoki, Tsuguo Fukuda
  • Publication number: 20070272898
    Abstract: A rare earth fluoride solid solution material (polycrystal and/or single crystal) characterized in that the material is obtained by mutually combining a plurality of rare earth fluorides having phase transitions and having different ion radii, respectively, so that the rare earth fluoride solid solution material is free of phase transitions. A rare earth fluoride solid solution material (polycrystal and/or single crystal) characterized in that the material is represented by (REyRE?1-y)F3 (0.0000<y<1.0000), wherein RE represents one or two or more selected from Sm, Eu, and Gd, and RE? represents one or two or more selected from Er, Tm, Yb, Lu, and Y. A rare earth fluoride solid solution material (polycrystal and/or single crystal) represented by MxREyRE?1-x-yFz, wherein RE is one or two or more selected from Ce, Pr, Nd, Eu, Tb, Ho, Er, Tm, or Yb, RE? is one or two or more selected from La, Sm, Gd, Dy, Lu, Y, and Sc, and M is one or more of Mg, Ca, Sr, and Ba.
    Type: Application
    Filed: April 12, 2005
    Publication date: November 29, 2007
    Inventors: Akira Yoshikawa, Kenji Aoki, Tomohiko Satonaga, Kei Kamada, Tsuguo Fukuda