Patents by Inventor Keiji Nakamura
Keiji Nakamura 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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Publication number: 20050116576Abstract: The invention provides a material for sliding contacts that is suitable for a small-sized DC motor used in recent downsized CD players and is excellent in durability. A material for sliding contacts used in a commutator of a small-sized DC motor that consists essentially of 0.01 to 3.0% Ni by weight, 0.01 to 6.0% ZnO by weight and/or 0.01 to 3.0% MgO by weight, furthermore, in some cases, 0.01 to 5.0% Cu by weight, and the balance Ag, in which Ni metal particles, ZnO particles or MgO particles are dispersed in the matrix of Ag.Type: ApplicationFiled: November 17, 2004Publication date: June 2, 2005Applicants: Mabuchi Motor Co., Ltd., Tanaka Kikinzoku Kogyo K. K.Inventors: Keiji Nakamura, Yasuhiro Hashimoto, Masahiro Takahashi, Shuichi Kubota, Takao Asada, Toshiya Yamamoto
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Patent number: 6894850Abstract: An objective lens driving apparatus includes a lens holder 1 that holds an objective lens 2, and a stationary base 9 that supports the lens holder 1 by a support shaft 3 parallel to an optical axis of the objective lens 2. A stationary yoke 11 and the magnet 8 are mounted to the stationary base 9. A focusing coil 4 and the tracking coils 5a and 5b are mounted to the lens holder 1. The interaction between the current in the focusing coil 4 and the magnetic field caused by the magnet 8 generates an electromagnetic force that moves the lens holder 1 along the support shaft 3. The interaction between the current in the tracking coils 5a and 5b and the magnetic field caused by the magnet 8 generates an electromagnetic force that rotates the lens holder 1 about the support shaft 3.Type: GrantFiled: January 6, 2003Date of Patent: May 17, 2005Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Keiji Nakamura, Mitoru Yabe
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Patent number: 6888689Abstract: An objective lens driving apparatus includes a lens holder 1 that holds an objective lens 2, and a stationary base 9 that supports the lens holder 1 by a support shaft 3 parallel to an optical axis of the objective lens 2. A stationary yoke 11 and the magnet 8 are mounted to the stationary base 9. A focusing coil 4 and the tracking coils 5a and 5b are mounted to the lens holder 1. The interaction between the current in the focusing coil 4 and the magnetic field caused by the magnet 8 generates an electromagnetic force that moves the lens holder 1 along the support shaft 3. The interaction between the current in the tracking coils 5a and 5b and the magnetic field caused by the magnet 8 generates an electromagnetic force that rotates the lens holder 1 about the support shaft 3.Type: GrantFiled: April 15, 2004Date of Patent: May 3, 2005Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Keiji Nakamura, Mitoru Yabe
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Publication number: 20050076353Abstract: An objective lens driving apparatus is used for accurately positioning an abject to focus a light spot on an optical recording medium. A lens holder holds the objective lens and has a bearing hole through which a shaft extends in a direction parallel to the optical axis so that the lens holder is rotatably supported on the shaft. Two magnets are supported on the lens holder so that the shaft is between the magnets. A base has two magnetic members disposed such that each of the two magnets exerts an attraction force on a corresponding one of the two magnetic members to urge the lens holder in a direction of the optical axis and in a direction perpendicular to the optical axis. A first coil set of first focusing and tracking coils and a second coil set of focusing and tracking coils are mounted to the two magnetic members.Type: ApplicationFiled: August 20, 2003Publication date: April 7, 2005Inventors: Keiji Nakamura, Mitoru Yabe
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Patent number: 6833409Abstract: An impact strength modifier comprises an acrylic rubber graft copolymer (I) obtained by graft-polymerizing a polyalkyl (meth)acrylate composite rubber (A) with a vinyl monomer (B), and a compound (II) which has a sulfonic acid group or a sulfuric acid group and also has two or more benzene ring skeletons, or a salt thereof. The polyalkyl (meth)acrylate composite rubber (A) contains two or more acrylic rubber components each having a different glass transition temperature, and the respective acrylic rubber components have 20% by weight or less of a monomer having two or more unsaturated bonds in a molecule. The compound (II) preferably has two or more benzene ring skeletons, and a particle size distribution of the polyalkyl (meth)acrylate composite rubber (A) is preferably a polydisperse distribution in which two or more peaks exist within a specific range.Type: GrantFiled: October 21, 2002Date of Patent: December 21, 2004Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Keiji Nakamura, Masakazu Ito
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Publication number: 20040190163Abstract: An objective lens driving apparatus includes a lens holder 1 that holds an objective lens 2, and a stationary base 9 that supports the lens holder 1 by a support shaft 3 parallel to an optical axis of the objective lens 2. A stationary yoke 11 and the magnet 8 are mounted to the stationary base 9. A focusing coil 4 and the tracking coils 5a and 5b are mounted to the lens holder 1. The interaction between the current in the focusing coil 4 and the magnetic field caused by the magnet 8 generates an electromagnetic force that moves the lens holder 1 along the support shaft 3. The interaction between the current in the tracking coils 5a and 5b and the magnetic field caused by the magnet 8 generates an electromagnetic force that rotates the lens holder 1 about the support shaft 3.Type: ApplicationFiled: April 15, 2004Publication date: September 30, 2004Applicant: Mitsubishi Denki Kabushiki KaishaInventors: Keiji Nakamura, Mitoru Yabe
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Publication number: 20040190403Abstract: An objective lens driving apparatus includes a lens holder 1 that holds an objective lens 2, and a stationary base 9 that supports the lens holder 1 by a support shaft 3 parallel to an optical axis of the objective lens 2. A stationary yoke 11 and the magnet 8 are mounted to the stationary base 9. A focusing coil 4 and the tracking coils 5a and 5b are mounted to the lens holder 1. The interaction between the current in the focusing coil 4 and the magnetic field caused by the magnet 8 generates an electromagnetic force that moves the lens holder 1 along the support shaft 3. The interaction between the current in the tracking coils 5a and 5b and the magnetic field caused by the magnet 8 generates an electromagnetic force that rotates the lens holder 1 about the support shaft 3.Type: ApplicationFiled: April 15, 2004Publication date: September 30, 2004Applicant: Mitsubishi Denki Kabushiki KaishaInventors: Keiji Nakamura, Mitoru Yabe
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Patent number: 6687062Abstract: An objective lens driving apparatus is used for accurately positioning an abject to focus a light spot on an optical recording medium. A lens holder holds the objective lens and has a bearing hole through which a shaft extends in a direction parallel to the optical axis so that the lens holder is rotatably supported on the shaft. Two magnets are supported on the lens holder so that the shaft is between the magnets. A base has two magnetic members disposed such that each of the two magnets exerts an attraction force on a corresponding one of the two magnetic members to urge the lens holder in a direction of the optical axis and in a direction perpendicular to the optical axis. A first coil set of first focusing and tracking coils and a second coil set of focusing and tracking coils are mounted to the two magnetic members.Type: GrantFiled: September 19, 2002Date of Patent: February 3, 2004Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Keiji Nakamura, Mitoru Yabe
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Patent number: 6646792Abstract: An optical output signal of an optical amplifier 1 branched by an optical divider/splitter 2 is separated by an optical demultiplexor 3 into different paths □1 to □n in accordance with the wavelength, and the level of each different wavelength component is adjusted under the control of an optical attenuator control circuit 9 on the basis of a transmission wavelength information notified through a transmission wavelength information input terminal 14. At this time, in the path corresponding to the wavelength transmitted, the attenuation amount of an optical attenuator is controlled to a minimum level, and in the path corresponding to the wavelength other than the wavelength transmitted, the attenuation amount of an optical attenuator is controlled to a maximum level. After the level adjustment, the different wavelength components are combined by an optical multiplexor 5, and the level of the combined signal is detected by a photo diode 6.Type: GrantFiled: June 13, 2002Date of Patent: November 11, 2003Assignee: NEC CorporationInventor: Keiji Nakamura
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Patent number: 6638334Abstract: The present invention is aimed at providing a sliding contact material that has an alloy composition containing no harmful substance like Cd, especially excellent contact resistance properties, electrical functions that are good and is not subject to secular change, and abrasion resistance practically bearing comparison with conventional sliding contact materials, and is aimed at lengthening the life of a motor by the use of a sliding contact material having excellent durability as a commutator for a small direct-current motor. The present invention is a sliding contact material of an Ag—Ni-based alloy that is used in sliding part electrically switching on and off by mechanical sliding action, and the material is a sliding contact material of Ni metal particle-dispersed-type Ag—Ni-based alloy that is produced in such a method that 0.7 to 3.0 wt. % Ni powder, an additive of Li2CO3 powder corresponding to 0.01 to 0.50 wt.Type: GrantFiled: July 1, 2002Date of Patent: October 28, 2003Assignees: Mabuchi Motor Co., Ltd., Tanaka Kikinzoku Kogyo K.K.Inventors: Keiji Nakamura, Takemasa Honma, Yasuhiro Hashimoto, Osamu Sakaguchi, Kengo Taneichi, Toshiya Yamamoto
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Publication number: 20030179471Abstract: An objective lens driving apparatus includes a lens holder 1 that holds an objective lens 2, and a stationary base 9 that supports the lens holder 1 by a support shaft 3 parallel to an optical axis of the objective lens 2. A stationary yoke 11 and the magnet 8 are mounted to the stationary base 9. A focusing coil 4 and the tracking coils 5a and 5b are mounted to the lens holder 1. The interaction between the current in the focusing coil 4 and the magnetic field caused by the magnet 8 generates an electromagnetic force that moves the lens holder 1 along the support shaft 3. The interaction between the current in the tracking coils 5a and 5b and the magnetic field caused by the magnet 8 generates an electromagnetic force that rotates the lens holder 1 about the support shaft 3.Type: ApplicationFiled: January 6, 2003Publication date: September 25, 2003Inventors: Keiji Nakamura, Mitoru Yabe
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Publication number: 20030114588Abstract: An impact strength modifier comprises an acrylic rubber graft copolymer (I) obtained by graft-polymerizing a polyalkyl (meth)acrylate composite rubber (A) with a vinyl monomer (B), and a compound (II) which has a sulfonic acid group or a sulfuric acid group and also has two or more benzene ring skeletons, or a salt thereof. The polyalkyl (meth)acrylate composite rubber (A) contains two or more acrylic rubber components each having a different glass transition temperature, and the respective acrylic rubber components have 20% by weight or less of a monomer having two or more unsaturated bonds in a molecule. The compound (II) preferably has two or more benzene ring skeletons, and a particle size distribution of the polyalkyl (meth)acrylate composite rubber (A) is preferably a polydisperse distribution in which two or more peaks exist within a specific range.Type: ApplicationFiled: October 21, 2002Publication date: June 19, 2003Inventors: Keiji Nakamura, Masakazu Ito
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Publication number: 20030090816Abstract: An objective lens driving apparatus is used for accurately positioning an abject to focus a light spot on an optical recording medium. A lens holder holds the objective lens and has a bearing hole through which a shaft extends in a direction parallel to the optical axis so that the lens holder is rotatably supported on the shaft. Two magnets are supported on the lens holder so that the shaft is between the magnets. A base has two magnetic members disposed such that each of the two magnets exerts an attraction force on a corresponding one of the two magnetic members to urge the lens holder in a direction of the optical axis and in a direction perpendicular to the optical axis. A first coil set of first focusing and tracking coils and a second coil set of focusing and tracking coils are mounted to the two magnetic members.Type: ApplicationFiled: September 19, 2002Publication date: May 15, 2003Inventors: Keiji Nakamura, Mitoru Yabe
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Publication number: 20030090785Abstract: An optical output signal of an optical amplifier 1 branched by an optical divider/splitter 2 is separated by an optical demultiplexor 3 into different paths &lgr;1 to &lgr;n in accordance with the wavelength, and the level of each different wavelength component is adjusted under the control of an optical attenuator control circuit 9 on the basis of a transmission wavelength information notified through a transmission wavelength information input terminal 14. At this time, in the path corresponding to the wavelength transmitted, the attenuation amount of an optical attenuator is controlled to a minimum level, and in the path corresponding to the wavelength other than the wavelength transmitted, the attenuation amount of an optical attenuator is controlled to a maximum level. After the level adjustment, the different wavelength components are combined by an optical multiplexor 5, and the level of the combined signal is detected by a photo diode 6.Type: ApplicationFiled: June 13, 2002Publication date: May 15, 2003Applicant: NEC CORPORATIONInventor: Keiji Nakamura
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Publication number: 20030061903Abstract: The present invention is aimed at providing a sliding contact material that has an alloy composition containing no harmful substance like Cd, especially excellent contact resistance properties, electrical functions that are good and is not subject to secular change, and abrasion resistance practically bearing comparison with conventional sliding contact materials, and is aimed at lengthening the life of a motor by the use of a sliding contact material having excellent durability as a commutator for a small direct-current motor. The present invention is a sliding contact material of an Ag—Ni-based alloy that is used in sliding part electrically switching on and off by mechanical sliding action, and the material is a sliding contact material of Ni metal particle-dispersed-type Ag—Ni-based alloy that is produced in such a method that 0.7 to 3.0 wt. % Ni powder, an additive of Li2CO3 powder corresponding to 0.01 to 0.50 wt.Type: ApplicationFiled: July 1, 2002Publication date: April 3, 2003Inventors: Keiji Nakamura, Takemasa Honma, Yasuhiro Hashimoto, Osamu Sakaguchi, Kengo Taneichi, Toshiya Yamamoto
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Patent number: 6521376Abstract: A non-aqueous liquid electrolyte cell comprising a positive electrode which has a metal oxide as an active material, a negative electrode, and a non-aqueous liquid electrolyte, in which the metal oxide has an average particle size of 40 to 150 &mgr;m, and the volume of the liquid electrolyte is 0.9 to 1.25 times as large as the volume of the metal oxide, which has good characteristics even at low temperature.Type: GrantFiled: November 24, 2000Date of Patent: February 18, 2003Assignee: Hitachi Maxell, Ltd.Inventors: Tadashi Sakata, Yoshifumi Sakamoto, Masanori Sugano, Akira Asada, Keiji Nakamura, Megumu Takai
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Patent number: 6486234Abstract: The present invention relates to an impact strength modifier capable of imparting both excellent weathering resistance and impact resistance, and to a resin composition comprising the impact strength modifier and a thermoplastic resin, particularly a rigid vinyl chloride resin. Since this impact strength modifier comprises, as a principal component, an acrylic rubber graft copolymer which is obtained by graft polymerization of a polyalkyl (meth)acrylate (A) rubber containing a plurality of acrylic rubber components composed of a specific monomer as a principal component, and a vinyl monomer (B), it is made possible to improve the impact resistance, particularly impact resistance at low temperatures, of the resin and to satisfactorily maintain the weathering resistance by adding a small amount of the impact strength modifier to the resin. This impact strength modifier is particularly suited for incorporation into a rigid vinyl chloride resin.Type: GrantFiled: January 12, 2001Date of Patent: November 26, 2002Assignee: Mitsubishi Rayon Co., Ltd.Inventors: Keiji Nakamura, Masakazu Ito, Akira Nakata
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Patent number: 6449411Abstract: An optical wavelength tunable filter includes an optical waveguide having a first branched optical waveguide and a second branched optical waveguide merging into one piece of the optical waveguide through which optical wavelength multiplexed signals, each having a different wavelength component being incident from an end face of the first branched optical waveguide, are propagated. A comb-type electrode (or a plurality of comb-type electrodes each corresponding to each of the different wavelength-components) is mounted vertically to apropagating direction of the optical wavelength multiplexed signals leaving a specified space apart from the optical waveguide formed by a merger of the branched first branched optical waveguide with the second branched optical waveguide. A voltage applying device applies a predetermined voltage to each of the comb-type electrodes.Type: GrantFiled: August 25, 2000Date of Patent: September 10, 2002Assignee: NEC CorporationInventor: Keiji Nakamura
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Publication number: 20020024717Abstract: A multi-wavelength light source having standard light sources, an optical fiber, to which standard lights emitted by the reference sources are supplied, generating a four-wave-mixing light from the supplied standard lights, and optical filters acquiring a plurality of lights having different frequencies from the four-wave-mixing light generated by the optical fiber. A part of the generated four-wave-mixing light is returned to the optical fiber as a fresh standard light.Type: ApplicationFiled: July 2, 2001Publication date: February 28, 2002Applicant: NEC CORPORATIONInventor: Keiji Nakamura
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Patent number: 6266756Abstract: When data that does not fill a bit size (32 bits) of a first register is stored in the first register, 8-bit data is supplied from a second register or a first constant generator to unfilled higher 16 bit positions of the first register, and a second constant generator supplies 8-bit data to fill the remaining bit positions in the first register.Type: GrantFiled: July 16, 1996Date of Patent: July 24, 2001Assignee: Ricoh Company, Ltd.Inventors: Kazuhiko Hara, Shinichi Yamaura, Keiichi Yoshioka, Keiji Nakamura, Takao Katayama