Patents by Inventor Koji Matsubara

Koji Matsubara 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: 6638846
    Abstract: A ZnO based oxide semiconductor layer is grown on a sapphire substrate 1 by supplying, for example, raw materials made of Zn and O constituting ZnO and a p-type dopant material made of N without supplying an n-type dopant material (a-step). By stopping the supply of the material of O and further supplying an n-type dopant material made of Ga, the semiconductor layer is doped with the p-type dopant and the n-type dopant, thereby forming a p-type ZnO layer (2a) (b-step). By repeating the steps (a) and (b) plural times, a p-type ZnO based oxide semiconductor layer is grown. As a result, N to be the p-type dopant can be doped in a stable carrier concentration also during high temperature growth in which a residual carrier concentration can be reduced, and the carrier concentration of the p-type layer made of the ZnO based oxide semiconductor can be increased sufficiently.
    Type: Grant
    Filed: September 13, 2001
    Date of Patent: October 28, 2003
    Assignee: National Institute of Advanced Industrial Science and Technology and Rohm Co., Ltd.
    Inventors: Kakuya Iwata, Paul Fons, Koji Matsubara, Akimasa Yamada, Shigeru Niki, Ken Nakahara
  • Publication number: 20030054914
    Abstract: A differential with a differential action limiting mechanism includes a differential mechanism D for distributing the drive force of an internal combustion engine inputted into a differential case 28 to a left-hand axle shaft 13 and a half shaft 11 which continuously connects to a right-hand axle shaft for output therefrom and friction clutches 44L, 44R for limiting differential rotations of the left-hand axle shaft 13 and the half shaft 11 relative to the differential case 28. An actuator A for generating an engagement force for bringing the friction clutches 44L, 44R into engagement is provided outside a housing 14 for accommodating therein the differential case 28, whereby an engagement force generated by the actuator A is transmitted to the friction clutches 44L, 44R via the half shaft 11.
    Type: Application
    Filed: September 13, 2002
    Publication date: March 20, 2003
    Applicant: Honda Giken Kogyo Kabushiki Kaisha
    Inventors: Tatsuhiro Tomari, Yutaka Tashiro, Akihiro Iwazaki, Koji Matsubara, Shinji Ohkuma, Shinichi Inagawa, Yasuji Shibahata
  • Patent number: 6531408
    Abstract: A substrate such as a sapphire substrate or the like is set to a molecular beam epitaxy (MBE) apparatus. Next, the temperature of the substrate is elevated to the temperature which is lower than the temperature at which a predetermined ZnO based oxide semiconductor layer (i.e. function layer) is grown (S1). Then, raw materials containing oxygen radical is irradiated to the substrate to grow a buffer layer made of ZnO based oxide semiconductor (S2). Subsequently, the irradiation of oxygen radical is stopped so as to eliminate the influence of oxygen onto the buffer layer (S3). Then, the temperature of the substrate is elevated to the temperature at which the predetermined ZnO based oxide semiconductor layer is grown (S4). After that, raw materials containing oxygen radical is irradiated so as to sequentially grow a ZnO based oxide semiconductor layer as a function layer (S5).
    Type: Grant
    Filed: August 28, 2001
    Date of Patent: March 11, 2003
    Assignees: National Institute of Advanced Industrial Science and Technology, Rohm Co., Ltd.
    Inventors: Kakuya Iwata, Paul Fons, Akimasa Yamada, Koji Matsubara, Shigeru Niki, Ken Nakahara
  • Publication number: 20030042851
    Abstract: A light-emitting device includes a silicon substrate, a ZnOSSe layer provided on the silicon substrate that is lattice-matched to the silicon substrate, and a separate confinement heterostructure light-emitting layer that is provided on the ZnOSSe layer and includes an active layer and upper and lower clad layers.
    Type: Application
    Filed: September 5, 2002
    Publication date: March 6, 2003
    Applicant: National Inst. of Advanced Ind. Science and Tech.
    Inventors: Kakuya Iwata, Shigeru Niki, Paul Fons, Akimasa Yamada, Koji Matsubara
  • Publication number: 20030019711
    Abstract: Two sensors are provided on a clutch core. Sensor coils are driven at a high frequency by a high-frequency driving circuit. As the sensors sense a magnetic flux of a magnetic circuit including the clutch core and an armature, the impedance of the sensor coils changes. In accordance with the outputs from the sensor coils at this point, an impedance detecting circuit detects the impedance of the sensor coils. Then, an impedance combining circuit combines the impedance of the sensor coils. On the basis of the combined impedance, a current control circuit controls a current supplied to an exciting coil. Thus, the attracting force of the armature to the core excited by the exciting coil is controlled.
    Type: Application
    Filed: July 2, 2002
    Publication date: January 30, 2003
    Inventors: Yasuo Nekado, Masaaki Kusumi, Ken Onoe, Akihiro Iwazaki, Koji Matsubara, Shinji Ohkuma, Tatsuhiro Tomari, Shinichi Inagawa
  • Patent number: 6472241
    Abstract: The closing plates (61b), (61c) are provided on the both end portions of the cylindrical insulator body (61a), the gas introduction tube for introducing a gaseous substance is inserted into one plate (61b) of the closing plates of the plasma chamber (61) for making the gaseous substance plasmatic within it, and on the other plate (61c), the plasma radiation outlet (61d) is provided. Then, nearby the plasma jet (63) outgoing from the radiation outlet, the electrode (64) for applying a high electric field of an ion trapper is provided so as to be opposed to the grounded electrode (65) interposed the plasma jet between them. This electrode for applying a high electric field is fixed on the grounded metal plate (61e) provided on the other plate (61c) via the insulation porcelain (66) made of MgO or quartz.
    Type: Grant
    Filed: August 28, 2001
    Date of Patent: October 29, 2002
    Assignees: National Institute of Advanced Industrial Science and Technology, Rohm Co., Ltd.
    Inventors: Kakuya Iwata, Paul Fons, Akimasa Yamada, Koji Matsubara, Shigeru Niki, Ken Nakahara
  • Publication number: 20020058351
    Abstract: In the case in which a ZnO based oxide semiconductor layer is to be hetero-epitaxially grown on a substrate formed of a material which is different from that of a ZnO based oxide semiconductor, the ZnO based oxide semiconductor layer is grown at a high temperature of 500° C. or more, and supply of oxygen is stopped and gradual cooling is carried out until a substrate temperature is lowered to 350° C. or less after the growth of the ZnO based oxide semiconductor layer is completed. As a result, it is possible to suppress the generation of dislocations or crystal defects over an epitaxial grown layer based on the atmosphere while the substrate temperature is lowered after the growth of the semiconductor layer and a difference in a coefficient of thermal expansion, thereby obtaining a semiconductor device having a high quality ZnO based oxide semiconductor layer which has an excellent crystalline property and a semiconductor light emitting device having the high characteristics.
    Type: Application
    Filed: September 13, 2001
    Publication date: May 16, 2002
    Inventors: Kakuya Iwata, Paul Fons, Koji Matsubara, Akimasa Yamada, Shigeru Niki, Ken Nakahara
  • Patent number: 6383408
    Abstract: A piezoelectric ceramic is provided which has a very low loss and superior workability in micro-fabrication. The piezoelectric ceramic contains at least Pb, Mn, Nb, Ti and Zr as primary metal components, in which, when the composition of the piezoelectric ceramic is represented by the formula Pbx{(MnaNbb)yTizZr(1−Y−z)}O3, the x, y, z, a, and b are, on a molar basis, such that 0.95≦x≦0.995, 0.055≦y≦0.10, 0.40≦z≦0.55, 2.01≦b/a≦2.40, and a+b=1. In addition, the average grain diameter of the sintered piezoelectric ceramic is about 2 &mgr;m or less.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: May 7, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Katsuhiro Horikawa, Koji Matsubara
  • Publication number: 20020034861
    Abstract: A ZnO based oxide semiconductor layer is grown on a sapphire substrate 1 by supplying, for example, raw materials made of Zn and O constituting ZnO and a p-type dopant material made of N without supplying an n-type dopant material (a-step). By stopping the supply of the material of O and further supplying an n-type dopant material made of Ga, the semiconductor layer is doped with the p-type dopant and the n-type dopant, thereby forming a p-type ZnO layer (2a) (b-step). By repeating the steps (a) and (b) plural times, a p-type ZnO based oxide semiconductor layer is grown. As a result, N to be the p-type dopant can be doped in a stable carrier concentration also during high temperature growth in which a residual carrier concentration can be reduced, and the carrier concentration of the p-type layer made of the ZnO based oxide semiconductor can be increased sufficiently.
    Type: Application
    Filed: September 13, 2001
    Publication date: March 21, 2002
    Inventors: Kakuya Iwata, Paul Fons, Koji Matsubara, Akimasa Yamada, Shigeru Niki, Ken Nakahara
  • Publication number: 20020030196
    Abstract: In an LED, for example, a light emitting layer forming portion (10) composed of a ZnO based oxide semiconductor is provided on a substrate (11), which includes at least an n-type layer (14) and a p-type layer (16) to form a light emitting layer. The p-type layer (16) contains phosphorus as a dopant. In order to dope such phosphorus, for example, a material having a bond of Zn and P such as Zn3P2 is used when growing a ZnO based oxide semiconductor. As a result, it is possible to obtain a semiconductor device including a p-type ZnO based oxide semiconductor layer having a stable and high carrier concentration and a method of manufacturing the semiconductor device.
    Type: Application
    Filed: September 13, 2001
    Publication date: March 14, 2002
    Inventors: Kakuya Iwata, Paul Fons, Koji Matsubara, Akimasa Yamada, Shigeru Niki, Ken Nakahara
  • Publication number: 20020025594
    Abstract: A substrate such as a sapphire substrate or the like is set to a molecular beam epitaxy (MBE) apparatus. Next, the temperature of the substrate is elevated to the temperature which is lower than the temperature at which a predetermined ZnO based oxide semiconductor layer (i.e. function layer) is grown (S1). Then, raw materials containing oxygen radical is irradiated to the substrate to grow a buffer layer made of ZnO based oxide semiconductor (S2). Subsequently, the irradiation of oxygen radical is stopped so as to eliminate the influence of oxygen onto the buffer layer (S3). Then, the temperature of the substrate is elevated to the temperature at which the predetermined ZnO based oxide semiconductor layer is grown (S4). After that, raw materials containing oxygen radical is irradiated so as to sequentially grow a ZnO based oxide semiconductor layer as a function layer (S5).
    Type: Application
    Filed: August 28, 2001
    Publication date: February 28, 2002
    Inventors: Kakuya Iwata, Paul Fons, Akimasa Yamada, Koji Matsubara, Shigeru Niki, Ken Nakahara
  • Publication number: 20020025621
    Abstract: The closing plates (61b), (61c) are provided on the both end portions of the cylindrical insulator body (61a), the gas introduction tube for introducing a gaseous substance is inserted into one plate (61b) of the closing plates of the plasma chamber (61) for making the gaseous substance plasmatic within it, and on the other plate (61c), the plasma radiation outlet (61d) is provided. Then, nearby the plasma jet (63) outgoing from the radiation outlet, the electrode (64) for applying a high electric field of an ion trapper is provided so as to be opposed to the grounded electrode (65) interposed the plasma jet between them. This electrode for applying a high electric field is fixed on the grounded metal plate (61e) provided on the other plate (61c) via the insulation porcelain (66) made of MgO or quartz.
    Type: Application
    Filed: August 28, 2001
    Publication date: February 28, 2002
    Inventors: Kakuya Iwata, Paul Fons, Akimasa Yamada, Koji Matsubara, Shigeru Niki, Ken Nakahara
  • Publication number: 20020014631
    Abstract: In such a construction that an active layer (5) for emitting light when a current is injected thereto is sandwiched between an n-type clad layer (4) and a p-type clad layer (6) which are made of a material having a larger band gap than that of the active layer, the above-mentioned active layer (5) is made of a compound semiconductor containing Zn, o, and a group VI type element other than O. As a result, it is possible to obtain such a semiconductor light emitting device as a blue type LED or LD, which is made of the harmless material and does not include Cd specifically, while using a ZnO-based compound semiconductor of narrow band gap with fewer crystal defects and excellent in crystallinity as a material of its active layer sandwiched between clad layers, and also improving its light emitting properties.
    Type: Application
    Filed: June 27, 2001
    Publication date: February 7, 2002
    Inventors: Kakuya Iwata, Paul Fons, Koji Matsubara, Akimasa Yamada, Shigeru Niki, Ken Nakahara