Patents by Inventor Yukio Wakui

Yukio Wakui 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).

  • Publication number: 20230421962
    Abstract: An object of the present invention is to provide a magnetic circuit for an acoustic transducer, the magnetic circuit enabling peeling of the surface of a member formed by compression-molding a soft magnetic composite material to be suppressed.
    Type: Application
    Filed: September 8, 2023
    Publication date: December 28, 2023
    Inventors: Takahiro TERADA, Yukio WAKUI, Tsunenori SANO, Masao NORO
  • Patent number: 9054028
    Abstract: A magnetic sensor for detecting the intensity of a magnetic field in three axial directions, in which a plurality of giant magnetoresistive elements are formed on a single semiconductor substrate. A thick film is formed on the semiconductor substrate; giant magnetoresistive elements forming X-axis and Y-axis sensors are formed on a planar surface thereof; and giant magnetoresistive elements forming a Z-axis sensor are formed using slopes of channels in the thick film. Each of the slopes of the channels can be constituted of a first slope and a second slope, so that a magneto-sensitive element is formed on the second slope having a larger inclination angle. In order to optimize the slope shape and inclination with respect to each channel, it is possible to form a dummy slope that does not directly relate to the formation of the giant magnetoresistive elements.
    Type: Grant
    Filed: April 30, 2012
    Date of Patent: June 9, 2015
    Assignee: Yamaha Corporation
    Inventors: Hiroshi Naito, Hideki Sato, Yukio Wakui, Masayoshi Omura
  • Publication number: 20120272514
    Abstract: A magnetic sensor for detecting the intensity of a magnetic field in three axial directions, in which a plurality of giant magnetoresistive elements are formed on a single semiconductor substrate. A thick film is formed on the semiconductor substrate; giant magnetoresistive elements forming X-axis and Y-axis sensors are formed on a planar surface thereof; and giant magnetoresistive elements forming a Z-axis sensor are formed using slopes of channels in the thick film. Each of the slopes of the channels can be constituted of a first slope and a second slope, so that a magneto-sensitive element is formed on the second slope having a larger inclination angle. In order to optimize the slope shape and inclination with respect to each channel, it is possible to form a dummy slope that does not directly relate to the formation of the giant magnetoresistive elements.
    Type: Application
    Filed: April 30, 2012
    Publication date: November 1, 2012
    Applicant: YAMAHA CORPORATION
    Inventors: Hiroshi Naito, Hideki Sato, Yukio Wakui, Masaysoshi Omura
  • Publication number: 20120268113
    Abstract: In a three-axis magnetic sensor, a plurality of magnetoresistive effect element bars are connected in series by means of bias magnets formed on a flat surface parallel to the flat surface of the substrate to constitute magnetoresistive effect elements. The sensitivity direction of magnetization is a direction perpendicular to the longitudinal direction of each of the magnetoresistive effect element bars. Magnetoresistive effect elements forming X-axis and Y-axis sensors have magnetization directions that are orthogonal to each other. Magnetoresistive effect elements of the Z-axis sensor are formed on a tilted surface substrate in such a way that the magnetization direction is inside the tilted surface. The sensitivity direction of the Z-axis sensor is perpendicular to the longitudinal direction of the magnetoresistive effect element bar.
    Type: Application
    Filed: June 13, 2012
    Publication date: October 25, 2012
    Applicant: YAMAHA CORPORATION
    Inventors: Hideki Sato, Masayoshi Omura, Hiroshi Naito, Toshiyuki Oohashi, Yukio Wakui, Chihiro Osuga
  • Patent number: 8178361
    Abstract: There is provided a small-size magnetic sensor for detecting the intensity of a magnetic field in three axial directions, in which a plurality of giant magnetoresistive elements are formed on a single semiconductor substrate. A thick film is formed on the semiconductor substrate; giant magnetoresistive elements forming an X-axis sensor and a Y-axis sensor are formed on a planar surface thereof; and giant magnetoresistive elements forming a Z-axis sensor are formed using slopes of channels formed in the thick film. Regarding the channel formation, it is possible to use the reactive ion etching and high-density plasma CVD methods. In addition, an insulating film is formed between the thick film and passivation film and is used as an etching stopper. Each of the slopes of the channels can be constituted of a first slope and a second slope, so that a magneto-sensitive element is formed on the second slope having a larger inclination angle.
    Type: Grant
    Filed: March 15, 2006
    Date of Patent: May 15, 2012
    Assignee: Yamaha Corporation
    Inventors: Hiroshi Naito, Hideki Sato, Yukio Wakui, Masayoshi Omura
  • Patent number: 7842334
    Abstract: A magnetic sensor includes a single substrate, a conventional GMR element formed of a spin-valve film including a single-layer-pinned fixed magnetization layer, and a SAF element formed of a synthetic spin-valve film including a plural-layer-pinned fixed magnetization layer. When the spin-valve film intended to act as the conventional GMR element and the synthetic spin-valve film intended to act as the SAF element are subjected to the application of a magnetic field oriented in a single direction at a high temperature, they become giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other. Since films intended to act as the conventional GMR element and the SAF element can be disposed close to each other, the magnetic sensor which has giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other can be small.
    Type: Grant
    Filed: February 6, 2008
    Date of Patent: November 30, 2010
    Assignee: Yamaha Corporation
    Inventors: Yukio Wakui, Masayoshi Omura
  • Patent number: 7633132
    Abstract: A magnetic sensor comprises a substrate, magnetoresistive element of a spin-valve type, a bias magnetic layer (or a permanent magnet film), and a protective film, wherein the bias magnetic layer is connected with both ends of the magnetoresistive element and the upper surface thereof is entirely covered with the lower surface of the magnetoresistive element at both ends. Herein, distances between the side surfaces of the both ends of the magnetoresistive element and the side surfaces of the bias magnetic layer viewed from the protective film do not exceed 3 ?m. In addition, a part of the bias magnetic layer can be covered with both ends of the magnetoresistive element, and an intermediate layer is arranged in relation to the magnetoresistive element, bias magnetic layer, and protective film so as to entirely cover the upper surface of the bias magnetic layer.
    Type: Grant
    Filed: February 9, 2007
    Date of Patent: December 15, 2009
    Assignee: Yamaha Corporation
    Inventors: Yukio Wakui, Susumu Yoshida, Kokichi Aiso
  • Patent number: 7606676
    Abstract: In a compass sensor unit, an azimuth data computing method is carried out by the steps of: inputting a signal from a geomagnetic sensor to measure magnetic field; determining whether to store measurement data of the magnetic field based on a distance from the last stored measurement data; calculating an offset value based on the stored data; making a comparison for each component of a plurality of measurement data used for calculating the offset value, and judging the offset value to be valid when a difference between the maximum and minimum values of each component is a given value or more; updating the already stored offset value to the offset value judged to be valid; and correcting newly provided measurement data by the updated offset value to compute azimuth data.
    Type: Grant
    Filed: September 8, 2008
    Date of Patent: October 20, 2009
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Yukio Wakui, Masayoshi Omura
  • Patent number: 7598835
    Abstract: The present invention aims to provide a magnetic sensor provided with a magnetoresistive effect element capable of stably maintaining a direction of magnetization in a magnetic domain of a free layer. The magnetic sensor includes a magnetoresistive effect element provided with narrow zonal portions 11a . . . 11a including a pinned layer and a free layer. Disposed below both ends of the free layer are bias magnet films 11b . . . 11b composed of a permanent magnet that applies to the free layer a bias magnetic field in a predetermined direction and an initializing coil 31 that is disposed in the vicinity of the free layer and applies to the free layer a magnetic field having the direction same as that of the bias magnetic field by being energized under a predetermined condition.
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: October 6, 2009
    Assignee: Yamaha Corporation
    Inventors: Toshiyuki Oohashi, Yukio Wakui
  • Patent number: 7589528
    Abstract: On a single chip are formed a plurality of magnetoresistance effect elements provided with pinned layers having fixed magnetization axes in the directions that cross each other. On a substrate 10 are formed magnetic layers that will become two magnetic tunnel effect elements 11, 21 as magnetoresistance effect elements. Magnetic-field-applying magnetic layers made of NiCo are formed to sandwich the magnetic layers in plan view. A magnetic field is applied to the magnetic-field-applying magnetic layers. The magnetic field is removed after the magnetic-field-applying magnetic layers are magnetized in the direction shown by arrow A.
    Type: Grant
    Filed: March 6, 2007
    Date of Patent: September 15, 2009
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Toshiyuki Oohashi, Yukio Wakui, Susumu Yoshida, Kokichi Aiso
  • Patent number: 7508196
    Abstract: A magnetic sensor includes first through fourth GMR elements. The fixed layers of the first through fourth GMR elements have respective magnetization directions toward the X-axis positive, X-axis negative, Y-axis negative, and Y-axis positive directions. When a magnet is located at the initial position, the free layers of the first through fourth GMR elements have respective magnetization directions toward the Y-axis positive, Y-axis negative, X-axis negative, and X-axis positive directions. When the magnet is located at the initial position, the magnetization axis of the magnet passes through the centroid of the first through fourth GMR elements. The magnetic sensor detects, from the resistances of these GMR elements, changes in horizontal magnetic fields of the magnet which pass through the first through fourth GMR elements and which change in accordance with the moved position of the magnet, to thereby determine the position of the magnet.
    Type: Grant
    Filed: March 28, 2006
    Date of Patent: March 24, 2009
    Assignee: Yamaha Corporation
    Inventors: Toshiyuki Oohashi, Yukio Wakui
  • Publication number: 20090027048
    Abstract: In the three-axis magnetic sensor of the present invention, a plurality of magnetoresistive effect element bars are connected in series by means of bias magnets to constitute magnetoresistive effect elements, and magnetoresistive effect elements of the X-axis sensor and those of the Y-axis sensor are formed on a flat surface parallel to the flat surface of the substrate. The sensitivity direction of magnetization is a direction vertical to the longitudinal direction of each of the magnetoresistive effect element bars, and magnetoresistive effect elements of the X-axis sensor and those of the Y-axis sensor are formed in such a way that the magnetization directions are orthogonal to each other. Further, magnetoresistive effect elements of the Z-axis sensor are formed on a tilted surface of the projection projected from the flat surface of the substrate in such a way that the magnetization direction is inside the tilted surface.
    Type: Application
    Filed: March 17, 2006
    Publication date: January 29, 2009
    Inventors: Hideki Sato, Masayoshi Omura, Hiroshi Naito, Toshiyuki Oohashi, Yukio Wakui, Chihiro Osuga
  • Patent number: 7474977
    Abstract: In a compass sensor unit, an azimuth data computing method is carried out by the steps of: inputting a signal from a geomagnetic sensor to measure magnetic field; determining whether to store measurement data of the magnetic field based on a distance from the last stored measurement data; calculating an offset value based on the stored data; making a comparison for each component of a plurality of measurement data used for calculating the offset value, and judging the offset value to be valid when a difference between the maximum and minimum values of each component is a given value or more; updating the already stored offset value to the offset value judged to be valid; and correcting newly provided measurement data by the updated offset value to compute azimuth data.
    Type: Grant
    Filed: November 30, 2007
    Date of Patent: January 6, 2009
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Yukio Wakui, Masayoshi Omura
  • Publication number: 20090006020
    Abstract: In a compass sensor unit, an azimuth data computing method is carried out by the steps of: inputting a signal from a geomagnetic sensor to measure magnetic field; determining whether to store measurement data of the magnetic field based on a distance from the last stored measurement data; calculating an offset value based on the stored data; making a comparison for each component of a plurality of measurement data used for calculating the offset value, and judging the offset value to be valid when a difference between the maximum and minimum values of each component is a given value or more; updating the already stored offset value to the offset value judged to be valid; and correcting newly provided measurement data by the updated offset value to compute azimuth data.
    Type: Application
    Filed: September 8, 2008
    Publication date: January 1, 2009
    Applicant: YAMAHA CORPORATION
    Inventors: HIDEKI SATO, Yukio Wakui, Masayoshi Omura
  • Publication number: 20080274270
    Abstract: A magnetic sensor includes a single substrate, a conventional GMR element formed of a spin-valve film including a single-layer-pinned fixed magnetization layer, and a SAF element formed of a synthetic spin-valve film including a plural-layer-pinned fixed magnetization layer. When the spin-valve film intended to act as the conventional GMR element and the synthetic spin-valve film intended to act as the SAF element are subjected to the application of a magnetic field oriented in a single direction at a high temperature, they become giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other. Since films intended to act as the conventional GMR element and the SAF element can be disposed close to each other, the magnetic sensor which has giant magnetoresistive elements whose magnetic-field-detecting directions are antiparallel to each other can be small.
    Type: Application
    Filed: February 6, 2008
    Publication date: November 6, 2008
    Applicant: YAMAHA CORPORATION
    Inventors: Yukio Wakui, Masayoshi Omura
  • Publication number: 20080169807
    Abstract: There is provided a small-size magnetic sensor for detecting the intensity of a magnetic field in three axial directions, in which a plurality of giant magnetoresistive elements are formed on a single semiconductor substrate. A thick film is formed on the semiconductor substrate; giant magnetoresistive elements forming an X-axis sensor and a Y-axis sensor are formed on a planar surface thereof; and giant magnetoresistive elements forming a Z-axis sensor are formed using slopes of channels formed in the thick film. Regarding the channel formation, it is possible to use the reactive ion etching and high-density plasma CVD methods. In addition, an insulating film is formed between the thick film and passivation film and is used as an etching stopper. Each of the slopes of the channels can be constituted of a first slope and a second slope, so that a magneto-sensitive element is formed on the second slope having a larger inclination angle.
    Type: Application
    Filed: March 15, 2006
    Publication date: July 17, 2008
    Inventors: Hiroshi Naito, Hideki Sato, Yukio Wakui, Masayoshi Omura
  • Publication number: 20080160184
    Abstract: A magnetic sensor comprises magnetoresistive elements and permanent magnet films, which are combined together to form GMR elements formed on a quartz substrate having a square shape, wherein the permanent magnet films are paired and connected to both ends of the magnetoresistive elements, so that an X-axis magnetic sensor and a Y-axis magnetic sensor are realized by adequately arranging the GMR elements relative to the four sides of the quartz substrate. Herein, the magnetization direction of the pinned layer of the magnetoresistive element forms a prescribed angle of 45° relative to the longitudinal direction of the magnetoresistive element or relative to the magnetization direction of the permanent magnet film. Thus, it is possible to reliably suppress offset variations of bridge connections of the GMR elements even when an intense magnetic field is applied; and it is therefore possible to noticeably improve the resistant characteristics to an intense magnetic field.
    Type: Application
    Filed: March 5, 2008
    Publication date: July 3, 2008
    Applicant: YAMAHA CORPORATION
    Inventors: Hideki Sato, Kokichi Aiso, Yukio Wakui
  • Patent number: 7394086
    Abstract: A magnetic sensor comprises a substrate, magnetoresistive element of a spin-valve type, a bias magnetic layer (or a permanent magnet film), and a protective film, wherein the bias magnetic layer is connected with both ends of the magnetoresistive element and the upper surface thereof is entirely covered with the lower surface of the magnetoresistive element at both ends. Herein, distances between the side surfaces of the both ends of the magnetoresistive element and the side surfaces of the bias magnetic layer viewed from the protective film do not exceed 3 ?m. In addition, a part of the bias magnetic layer can be covered with both ends of the magnetoresistive element, and an intermediate layer is arranged in relation to the magnetoresistive element, bias magnetic layer, and protective film so as to entirely cover the upper surface of the bias magnetic layer.
    Type: Grant
    Filed: July 15, 2004
    Date of Patent: July 1, 2008
    Assignee: Yamaha Corporation
    Inventors: Yukio Wakui, Susumu Yoshida, Kokichi Aiso
  • Patent number: 7363718
    Abstract: Data are input from a geomagnetic sensor that detects magnetic fields in three axial directions, and magnetic field data are measured on the basis of the input data. The measured magnetic field data are sequentially stored, and a determination is made as to whether a plurality of the magnetic field data thus stored lie within a same plane in a three-dimensional orientation space. When it has been determined that the plurality of the magnetic field data lie within the same plane in the three-dimensional orientation space, center coordinates of a circular arc where the stored magnetic field data lie are calculated, as provisional offset values, on the basis of the magnetic field data and in accordance with a predetermined algorithm. Magnetic field data measured after the calculation of the provisional offset values is corrected with the provisional offset values, and an arithmetic operation is performed for determining orientation data on the basis of the corrected magnetic field data.
    Type: Grant
    Filed: May 18, 2007
    Date of Patent: April 29, 2008
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Yukio Wakui
  • Patent number: 7362548
    Abstract: A magnetic sensor comprises magnetoresistive elements and permanent magnet films, which are combined together to form GMR elements formed on a quartz substrate having a square shape, wherein the permanent magnet films are paired and connected to both ends of the magnetoresistive elements, so that an X-axis magnetic sensor and a Y-axis magnetic sensor are realized by adequately arranging the GMR elements relative to the four sides of the quartz substrate. Herein, the magnetization direction of the pinned layer of the magnetoresistive element forms a prescribed angle of 45° relative to the longitudinal direction of the magnetoresistive element or relative to the magnetization direction of the permanent magnet film. Thus, it is possible to reliably suppress offset variations of bridge connections of the GMR elements even when an intense magnetic field is applied; and it is therefore possible to noticeably improve the resistant characteristics to an intense magnetic field.
    Type: Grant
    Filed: August 2, 2006
    Date of Patent: April 22, 2008
    Assignee: Yamaha Corporation
    Inventors: Hideki Sato, Kokichi Aiso, Yukio Wakui