Patents by Inventor Kazuhiko Maejima

Kazuhiko Maejima 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: 10964879
    Abstract: A method of manufacturing a dielectric device includes epitaxially growing a metal film on a substrate, forming a dielectric film on the metal film such that the dielectric film has a preferentially oriented structure, forming a first electrode film having a non-oriented or amorphous structure on the dielectric film, removing the substrate and the metal film from the dielectric film or removing the substrate from the metal film, and forming a second electrode film having a non-oriented or amorphous structure on the dielectric film or the metal film.
    Type: Grant
    Filed: November 1, 2017
    Date of Patent: March 30, 2021
    Assignee: TDK CORPORATION
    Inventors: Katsuyuki Kurachi, Hitoshi Sakuma, Yasuhiro Aida, Kazuhiko Maejima, Mayumi Nakajima
  • Publication number: 20180076379
    Abstract: A dielectric device has a first electrode film having a non-oriented or amorphous structure, a dielectric film provided on the first electrode film and having a preferentially oriented structure, and a second electrode film provided on the dielectric film and having a non-oriented or amorphous structure.
    Type: Application
    Filed: November 1, 2017
    Publication date: March 15, 2018
    Applicant: TDK CORPORATION
    Inventors: Katsuyuki KURACHI, Hitoshi SAKUMA, Yasuhiro AIDA, Kazuhiko MAEJIMA, Mayumi NAKAJIMA
  • Patent number: 9331262
    Abstract: A thin film piezoelectric element according to the present invention includes a potassium sodium niobate thin film having a structure in which a plurality of crystal grains are present in a film thickness direction; and a pair of electrode films sandwiching the potassium sodium niobate thin film. When the potassium sodium niobate thin film is divided into three regions of the same thickness in the film thickness direction and average crystal grain sizes A1, A2, and A3 of the respective regions are determined, a ratio m/M of the smallest average crystal grain size m among A1, A2, and A3 to the largest average crystal grain size M among A1, A2, and A3 is 10% to 80%. The region having the smallest average crystal grain size m lies next to one of the pair of electrode films.
    Type: Grant
    Filed: May 20, 2013
    Date of Patent: May 3, 2016
    Assignee: TDK CORPORATION
    Inventors: Kazuhiko Maejima, Yasuhiro Aida, Yoshitomo Tanaka, Katsuyuki Kurachi, Hitoshi Sakuma
  • Patent number: 9277869
    Abstract: There are provided a thin-film piezoelectric element including a piezoelectric thin film which has an alkali niobate-based perovskite structure represented by the composition formula (K1-w-xNawSrx)m(Nb1-yZry)O3 and which is preferentially oriented to (001), and a pair of electrode films that sandwich the piezoelectric thin film, a thin-film piezoelectric actuator, and a thin-film piezoelectric sensor each including the thin-film piezoelectric element.
    Type: Grant
    Filed: October 7, 2013
    Date of Patent: March 8, 2016
    Assignee: TDK CORPORATION
    Inventors: Katsuyuki Kurachi, Yasuhiro Aida, Hitoshi Sakuma, Kazuhiko Maejima
  • Patent number: 9147827
    Abstract: An object is to reduce the leakage current of a piezoelectric element including a potassium-sodium niobate thin film, enhance the reliability of the piezoelectric element and, in addition, enhance the withstand voltage by including a pair of electrodes and a piezoelectric layer sandwiched between the above-described pair of electrode layers, wherein the above-described piezoelectric layer is provided with at least one layer each of first piezoelectric layer which is a potassium-sodium niobate thin film substantially not containing Mn (manganese) and second piezoelectric layer which is a potassium-sodium niobate thin film containing Mn.
    Type: Grant
    Filed: November 28, 2012
    Date of Patent: September 29, 2015
    Assignee: TDK CORPORATION
    Inventors: Yasuhiro Aida, Katsuyuki Kurachi, Hitoshi Sakuma, Kazuhiko Maejima
  • Patent number: 9147826
    Abstract: An object is to increase the amount of displacement of a thin-film piezoelectric element including a piezoelectric thin film having an uneven-shaped contact surface with the planar shape and the layer structure of the thin-film piezoelectric element kept unchanged. The thin-film piezoelectric element includes a pair of electrode layers and a piezoelectric thin film sandwiched between the pair of electrode layers, in which a surface roughness P-V of an interface between the piezoelectric thin film and at least one of the pair of electrode layers is 220 nm or more and 500 nm or less.
    Type: Grant
    Filed: January 23, 2014
    Date of Patent: September 29, 2015
    Assignee: TDK CORPORATION
    Inventors: Hitoshi Sakuma, Kazuhiko Maejima
  • Patent number: 9136820
    Abstract: A piezoelectric device according to the present invention is provided with a pair of electrode films, a piezoelectric film sandwiched in between the pair of electrode films, and a stress control film which is in direct contact with a surface of at least one of the pair of electrode films, on the side where the electrode film is not in contact with the piezoelectric film, and which has a linear expansion coefficient larger than those of the relevant electrode film and the piezoelectric film.
    Type: Grant
    Filed: July 31, 2012
    Date of Patent: September 15, 2015
    Assignee: TDK CORPORATION
    Inventors: Yasuhiro Aida, Katsuyuki Kurachi, Hitoshi Sakuma, Kazuhiko Maejima
  • Patent number: 9130169
    Abstract: A piezoelectric element includes, as a piezoelectric layer, a thin film of potassium sodium niobate that is a perovskite compound represented by a general expression ABO3, in which Sr (strontium) is substituted on both of an A site and a B site and Mn (manganese) is substituted only on the A site. Accordingly, the piezoelectric element is provided to decrease a leak current of the piezoelectric element using the thin film of potassium sodium niobate, to increase a withstand voltage thereof and to improve piezoelectric characteristics thereof.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: September 8, 2015
    Assignee: TDK CORPORATION
    Inventors: Yasuhiro Aida, Yoshitomo Tanaka, Hitoshi Sakuma, Katsuyuki Kurachi, Kazuhiko Maejima
  • Publication number: 20150207057
    Abstract: An object is to increase the amount of displacement of a thin-film piezoelectric element including a piezoelectric thin film having an uneven-shaped contact surface with the planar shape and the layer structure of the thin-film piezoelectric element kept unchanged. The thin-film piezoelectric element includes a pair of electrode layers and a piezoelectric thin film sandwiched between the pair of electrode layers, in which a surface roughness P-V of an interface between the piezoelectric thin film and at least one of the pair of electrode layers is 220 nm or more and 500 nm or less.
    Type: Application
    Filed: January 23, 2014
    Publication date: July 23, 2015
    Inventors: Hitoshi SAKUMA, Kazuhiko MAEJIMA
  • Patent number: 9076968
    Abstract: A piezoelectric element includes, as a piezoelectric layer, a thin film of potassium sodium niobate that is a perovskite compound represented by a general expression ABO3, in which Ta (tantalum) is substituted on both of an A site and a B site. Accordingly, the piezoelectric element is provided to increase a reliability of the piezoelectric element using the thin film of potassium sodium niobate and to improve piezoelectric characteristics thereof.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: July 7, 2015
    Assignee: TDK CORPORATION
    Inventors: Yasuhiro Aida, Yoshitomo Tanaka, Hitoshi Sakuma, Katsuyuki Kurachi, Kazuhiko Maejima
  • Patent number: 9065049
    Abstract: A thin film piezoelectric device according to the present invention includes a pair of electrode layers and a piezoelectric thin film interposed between the pair of electrode layers, wherein the piezoelectric thin film contains a rare gas element and has a content gradient of the rare gas element in the thickness direction of the piezoelectric thin film.
    Type: Grant
    Filed: September 21, 2012
    Date of Patent: June 23, 2015
    Assignee: TDK CORPORATION
    Inventors: Hitoshi Sakuma, Yasuhiro Aida, Katsuyuki Kurachi, Kazuhiko Maejima
  • Patent number: 9022532
    Abstract: The displacement as an actuator or the sensitivity as a sensor of a piezoelectric element can be increased and, in addition, the electric power consumption can be reduced by providing a thin film of potassium-sodium niobate, which is a perovskite type compound represented by a general formula ABO3, as a piezoelectric layer, wherein a crystal orientation of a crystal structure of potassium-sodium niobate has in-plane fourfold symmetry as a whole piezoelectric layer, where a first axis of rotational symmetry is a thickness direction of the piezoelectric layer.
    Type: Grant
    Filed: October 21, 2013
    Date of Patent: May 5, 2015
    Assignee: TDK Corporation
    Inventors: Yasuhiro Aida, Ryu Ohta, Yoshitomo Tanaka, Hiroshi Chihara, Hitoshi Sakuma, Kazuhiko Maejima
  • Publication number: 20150109372
    Abstract: The displacement as an actuator or the sensitivity as a sensor of a piezoelectric element can be increased and, in addition, the electric power consumption can be reduced by providing a thin film of potassium-sodium niobate, which is a perovskite type compound represented by a general formula ABO3, as a piezoelectric layer, wherein a crystal orientation of a crystal structure of potassium-sodium niobate has in-plane fourfold symmetry as a whole piezoelectric layer, where a first axis of rotational symmetry is a thickness direction of the piezoelectric layer.
    Type: Application
    Filed: October 21, 2013
    Publication date: April 23, 2015
    Inventors: Yasuhiro AIDA, Ryu OHTA, Yoshitomo TANAKA, Hiroshi CHIHARA, Hitoshi SAKUMA, Kazuhiko MAEJIMA
  • Patent number: 8994251
    Abstract: A piezoelectric device according to the present invention is provided with a first electrode film, a first nonmetal electroconductive intermediate film provided on the first electrode film, a piezoelectric film provided on the first nonmetal electroconductive intermediate film, a second nonmetal electroconductive intermediate film provided on the piezoelectric film, and a second electrode film provided on the second nonmetal electroconductive intermediate film. A linear expansion coefficient of the first nonmetal electroconductive intermediate film is larger than those of the first electrode film and the piezoelectric film, and a linear expansion coefficient of the second nonmetal electroconductive intermediate film is larger than those of the second electrode film and the piezoelectric film.
    Type: Grant
    Filed: August 3, 2012
    Date of Patent: March 31, 2015
    Assignee: TDK Corporation
    Inventors: Katsuyuki Kurachi, Yasuhiro Aida, Hitoshi Sakuma, Kazuhiko Maejima
  • Patent number: 8981627
    Abstract: A piezoelectric device has a first electrode film, a piezoelectric film provided on the first electrode film, and a second electrode film provided on the piezoelectric film. At least one of the pair of electrode films is composed of an alloy, and a major component of the alloy is a metal selected from the group consisting of Ti, Al, Mg, and Zn.
    Type: Grant
    Filed: June 4, 2012
    Date of Patent: March 17, 2015
    Assignee: TDK Corporation
    Inventors: Hitoshi Sakuma, Katsuyuki Kurachi, Yasuhiro Aida, Kazuhiko Maejima, Mayumi Nakajima
  • Publication number: 20140339961
    Abstract: A thin film piezoelectric element according to the present invention includes a potassium sodium niobate thin film having a structure in which a plurality of crystal grains are present in a film thickness direction; and a pair of electrode films sandwiching the potassium sodium niobate thin film. When the potassium sodium niobate thin film is divided into three regions of the same thickness in the film thickness direction and average crystal grain sizes A1, A2, and A3 of the respective regions are determined, a ratio m/M of the smallest average crystal grain size m among A1, A2, and A3 to the largest average crystal grain size M among A1, A2, and A3 is 10% to 80%. The region having the smallest average crystal grain size m lies next to one of the pair of electrode films.
    Type: Application
    Filed: May 20, 2013
    Publication date: November 20, 2014
    Inventors: Kazuhiko MAEJIMA, Yasuhiro AIDA, Yoshitomo TANAKA, Katsuyuki KURACHI, Hitoshi SAKUMA
  • Publication number: 20140265724
    Abstract: A piezoelectric element includes, as a piezoelectric layer, a thin film of potassium sodium niobate that is a perovskite compound represented by a general expression ABO3, in which Ta (tantalum) is substituted on both of an A site and a B site. Accordingly, the piezoelectric element is provided to increase a reliability of the piezoelectric element using the thin film of potassium sodium niobate and to improve piezoelectric characteristics thereof.
    Type: Application
    Filed: March 14, 2013
    Publication date: September 18, 2014
    Applicant: TDK CORPORATION
    Inventors: Yasuhiro AIDA, Yoshitomo TANAKA, Hitoshi SAKUMA, Katsuyuki KURACHI, Kazuhiko MAEJIMA
  • Publication number: 20140145555
    Abstract: There are provided a thin-film piezoelectric element including a piezoelectric thin film which has an alkali niobate-based perovskite structure represented by the composition formula (K1-w-xNawSrx)m(Nb1-yZry)O3 and which is preferentially oriented to (001), and a pair of electrode films that sandwich the piezoelectric thin film, a thin-film piezoelectric actuator, and a thin-film piezoelectric sensor each including the thin-film piezoelectric element.
    Type: Application
    Filed: October 7, 2013
    Publication date: May 29, 2014
    Applicant: TDK CORPORATION
    Inventors: Katsuyuki KURACHI, Yasuhiro AIDA, Hitoshi SAKUMA, Kazuhiko MAEJIMA
  • Publication number: 20140084754
    Abstract: A thin film piezoelectric device according to the present invention includes a potassium sodium niobate-based piezoelectric thin film having an average crystal grain diameter of 60 nm or more and 90 nm or less, and a pair of electrode films configured to hold the piezoelectric thin film therebetween.
    Type: Application
    Filed: September 21, 2012
    Publication date: March 27, 2014
    Applicant: TDK CORPORATION
    Inventors: Kazuhiko MAEJIMA, Katsuyuki KURACHI, Hitoshi SAKUMA, Yasuhiro AIDA, Yoshitomo TANAKA
  • Publication number: 20140084749
    Abstract: A thin film piezoelectric device according to the present invention includes a pair of electrode layers and a piezoelectric thin film interposed between the pair of electrode layers, wherein the piezoelectric thin film contains a rare gas element and has a content gradient of the rare gas element in the thickness direction of the piezoelectric thin film.
    Type: Application
    Filed: September 21, 2012
    Publication date: March 27, 2014
    Applicant: TDK CORPORATION
    Inventors: Hitoshi SAKUMA, Yasuhiro AIDA, Katsuyuki KURACHI, Kazuhiko MAEJIMA