Patents by Inventor Ken Tamanoi
Ken Tamanoi 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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Patent number: 8890620Abstract: A power amplifier includes a first matching circuit configured to perform harmonic processing of an input signal, and a second matching circuit configured to perform the harmonic processing of an output signal, the output signal being generated by amplifying a power of the input signal. The power amplifier rotates a phase of output impedance at a matching point of the harmonic included in the generated output signal when the power of the input signal is decreased from a value higher than a certain value to a value lower than the certain value.Type: GrantFiled: November 20, 2012Date of Patent: November 18, 2014Assignee: Fujitsu LimitedInventors: Ken Tamanoi, Toru Maniwa
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Publication number: 20140292405Abstract: An amplification device includes: an amplitude adjustment circuit configured to adjust an amplitude level of an input signal so as to keep the amplitude level within a given range; an amplifier configured to amplify the adjusted signal; and a circuitry configured to change an amplitude level of the amplified signal, based on the amplitude level of the input signal and a first distortion compensation corresponding to the amplitude level of the input signal.Type: ApplicationFiled: March 25, 2014Publication date: October 2, 2014Applicant: FUJITSU LIMITEDInventors: Takeshi TAKANO, Shigekazu KIMURA, Ken TAMANOI, Masakazu KOJIMA, Toru MANIWA, Yasuyuki OISHI, Michiharu NAKAMURA, Kazuo NAGATANI
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Publication number: 20140285262Abstract: A control device of a power amplifier includes: a limiter configured to limit a level of an input signal to the power amplifier; and a control unit configured to, when the limiter operates, make an operation voltage of the power amplifier invariable and control load of an output matching circuit of the power amplifier based on an amplitude of the input signal, and, when the limiter does not operate, to make the load of the output matching circuit invariable and control the operation voltage of the power amplifier.Type: ApplicationFiled: November 26, 2013Publication date: September 25, 2014Applicant: FUJITSU LIMITEDInventors: Masakazu KOJIMA, Shigekazu Kimura, Takeshi Takano, Toru Maniwa, Ken Tamanoi
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Publication number: 20140184326Abstract: A power amplifier includes: an amplifier; a matching circuit, including a variable reactance magnetic device having a reactance which varies in accordance with a magnetic field, configured to match an output of the amplifier with a certain impedance; an amplitude detector configured to detect the amplitude of an input signal for the amplifier; and a magnetic-field control circuit configured to apply a magnetic field corresponding to the amplitude detected by the amplitude detector to the variable reactance magnetic device.Type: ApplicationFiled: October 22, 2013Publication date: July 3, 2014Applicant: FUJITSU LIMITEDInventor: Ken TAMANOI
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Publication number: 20140055199Abstract: A power amplification device, includes: an amplifier to amplify an input signal; a switched capacitor, provided at an output stage of the amplifier, to change capacitance based on a first control signal; a matching unit, provided at the output stage of the amplifier and including a varactor pair in which two varactor diodes are coupled in series or a varactor pair in which two varactor diodes are coupled in parallel, to change capacitance based on a second control signal; a detection circuit to detect power of the input signal; a quantization circuit to quantize a detected power value, form a quantized bit string having a high-order bit group and a low-order bit group, and output the high-order bit group as the first control signal to the switched capacitor; and a conversion circuit to convert the low-order bit group into an analog value and form the second control signal.Type: ApplicationFiled: June 6, 2013Publication date: February 27, 2014Inventors: Takeshi TAKANO, Masakazu Kojima, Michiharu Nakamura, Toru Maniwa, Shigekazu Kimura, Ken Tamanoi
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Publication number: 20100061135Abstract: A magnetic wire unit for storing information thereon includes a magnetic wire containing a material having an axis of easy magnetization, and extending in a first direction, the axis being switchable between the first direction and the second direction perpendicular to the first direction, the magnetic wire being capable of holding a plurality of magnetic domains representing information. The magnetic wire unit includes a current supply unit for applying an electric current to the magnetic wire so as to move magnetic domain walls defining the magnetic domains in the magnetic wire.Type: ApplicationFiled: August 6, 2009Publication date: March 11, 2010Applicant: FUJITSU LIMITEDInventors: Keiichi Nagasaka, Hiroshi Ashida, Takao Ochiai, Ken Tamanoi
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Publication number: 20090181166Abstract: A recording medium includes a substrate, a recording layer provided with perpendicular magnetic anisotropy for recording of information, a foundation layer disposed between the substrate and the recording layer, an initial layer which is greater in surface tension than the foundation layer and held in contact with a recoding-layer-side surface of the foundation layer, and a functional layer held in contact with a recoding-layer-side surface of the initial layer.Type: ApplicationFiled: March 25, 2009Publication date: July 16, 2009Applicant: FUJITSU LIMITEDInventors: Takeshi Morikawa, Ken Tamanoi, Takuya Kamimura
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Patent number: 7521135Abstract: A recording medium includes a substrate, a recording layer provided with perpendicular magnetic anisotropy for recording of information, a foundation layer disposed between the substrate and the recording layer, an initial layer which is greater in surface tension than the foundation layer and held in contact with a recoding-layer-side surface of the foundation layer, and a functional layer held in contact with a recoding-layer-side surface of the initial layer.Type: GrantFiled: March 24, 2004Date of Patent: April 21, 2009Assignee: Fujitsu LimitedInventors: Takeshi Morikawa, Ken Tamanoi, Takuya Kamimura
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Patent number: 7164623Abstract: The present invention provides a magneto-optical recording medium including a recording layer, an intermediate layer and a reproducing layer stacked in this order. Information recorded in the recording layer is transferred to the reproducing layer through the intermediate layer so that the information is reproduced. The reproducing layer includes an upper reproducing layer, a coupling layer, and a lower reproducing layer formed in this order on the intermediate layer. Magnetic information in the upper reproducing layer in an area whose temperature is increased to a predetermined temperature is transferred to the lower reproducing layer through the coupling layer.Type: GrantFiled: August 25, 2004Date of Patent: January 16, 2007Assignee: Fujitsu LimitedInventors: Ryo Kurita, Ken Tamanoi, Shoyu Ito, Motonobu Mihara
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Patent number: 7090933Abstract: The invention is a magneto-optical recording medium characterized by containing at least a soft magnetic layer, a protective layer, a resin layer having a servo pattern formed thereon, a reflecting film, a lower dielectric material film, a recording film, an upper dielectric material film, and a cover layer, formed on a substrate in this order.Type: GrantFiled: June 8, 2004Date of Patent: August 15, 2006Assignee: Fujitsu LimitedInventors: Yuzuru Yamakage, Takuya Kamimura, Ken Tamanoi, Mineo Moribe, Keiji Shono
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Publication number: 20050146993Abstract: The present invention relates to a magneto-optical recording medium having a recording layer on which data is recorded by irradiation with recording light and application of a magnetic field and being irradiated with recording light and supplied with a magnetic field on the recording layer side. An object of the present invention is to provide a magneto-optical recording medium that is capable of being irradiated with a high-power laser beam without increasing media noise during reproduction and a recording layer of which can be heated sufficiently with a moderate-power laser beam to reduce its magnetic coercivity during recording.Type: ApplicationFiled: December 10, 2004Publication date: July 7, 2005Inventors: Takuya Kamimura, Tsutomu Tanaka, Ken Tamanoi, Koji Matsumoto
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Publication number: 20050068855Abstract: A recording medium includes a substrate, a recording layer provided with perpendicular magnetic anisotropy for recording of information, a foundation layer disposed between the substrate and the recording layer, an initial layer which is greater in surface tension than the foundation layer and held in contact with a recoding-layer-side surface of the foundation layer, and a functional layer held in contact with a recoding-layer-side surface of the initial layer.Type: ApplicationFiled: March 24, 2004Publication date: March 31, 2005Inventors: Takeshi Morikawa, Ken Tamanoi, Takuya Kamimura
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Patent number: 6865039Abstract: A master medium for magnetic transfer includes a substrate having a concave portion formed in its surface corresponding to a pattern of recorded information to be transferred; a first perpendicular ferromagnetic layer deposited in the concave portion; and a second perpendicular ferromagnetic layer layered on the substrate surface and the first perpendicular ferromagnetic layer surface. The substrate surface and the first perpendicular ferromagnetic layer surface are flattened to form a single flat surface. In the master medium for magnetic transfer, a magnetic field change in a direction parallel to the substrate surface at a magnetization boundary of the first perpendicular ferromagnetic layer is steep. Since the influence of the change of an external magnetic field is reduced, it is possible to perform accurate transfer from the master medium for magnetic transfer to a slave medium for magnetic recording.Type: GrantFiled: March 20, 2002Date of Patent: March 8, 2005Assignee: Fujitsu LimitedInventors: Shingo Hamaguchi, Sumio Kuroda, Kazuyuki Ozaki, Ken Tamanoi, Koji Matsumoto
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Publication number: 20050024993Abstract: The present invention provides a magneto-optical recording medium including a recording layer, an intermediate layer and a reproducing layer stacked in this order. Information recorded in the recording layer is transferred to the reproducing layer through the intermediate layer so that the information is reproduced. The reproducing layer includes an upper reproducing layer, a coupling layer, and a lower reproducing layer formed in this order on the intermediate layer. Magnetic information in the upper reproducing layer in an area whose temperature is increased to a predetermined temperature is transferred to the lower reproducing layer through the coupling layer.Type: ApplicationFiled: August 25, 2004Publication date: February 3, 2005Inventors: Ryo Kurita, Ken Tamanoi, Shoyu Ito, Motonobu Mihara
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Patent number: 6844083Abstract: A magneto-optical recording medium has a configuration such that information recorded can be read from a region smaller than a beam spot by applying an external magnetic field and directing a light beam in reproducing. The magneto-optical recording medium includes a magnetic recording layer for recording and holding information, a magnetic reproducing layer provided on one side of the magnetic recording layer on which the light beam is incident, a nonmagnetic layer provided on another side of the magnetic recording layer opposite to the magnetic reproducing layer, and a magnetic assist layer provided on the nonmagnetic layer. The magnetic assist layer has a coercive force smaller than an external magnetic field applied in recording or reproducing information.Type: GrantFiled: July 29, 2003Date of Patent: January 18, 2005Assignee: Fujitsu LimitedInventors: Toshio Sugimoto, Ken Tamanoi
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Patent number: 6821642Abstract: A magneto-optical recording medium includes at least three magnetic layers of a first magnetic layer, a second magnetic layer and a third magnetic layer, in which a recording mark recorded in the third magnetic layer by irradiation of a light beam is transferred through the second magnetic layer formed above the third magnetic layer to the first magnetic layer formed above the second magnetic layer for reproduction, wherein the first magnetic layer is provided with a high temperature mask having no spontaneous magnetization in a region where its temperature becomes a predetermined temperature or higher.Type: GrantFiled: September 25, 2001Date of Patent: November 23, 2004Assignee: Fujitsu LimitedInventor: Ken Tamanoi
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Publication number: 20040224119Abstract: The invention is a magneto-optical recording medium characterized by containing at least a soft magnetic layer, a protective layer, a resin layer having a servo pattern formed thereon, a reflecting film, a lower dielectric material film, a recording film, an upper dielectric material film, and a cover layer, formed on a substrate in this order.Type: ApplicationFiled: June 8, 2004Publication date: November 11, 2004Applicant: FUJITSU LIMITEDInventors: Yazuru Yamakage, Takuya Kamimura, Ken Tamanoi, Mineo Moribe, Keiji Shono
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Patent number: 6770387Abstract: A magneto-optical recording medium comprising four magnetic layers including a mask layer, a reproduction layer, an intermediate layer and a recording layer, wherein the reproduction layer and the recording layer each have a direction of easy magnetization extending in a layer stacking direction at room temperature, the mask layer and the intermediate layer each have a direction of easy magnetization extending in an in-plane direction at room temperature, the mask layer, the reproduction layer, the intermediate layer and the recording layer have Curie temperatures Tc1, Tc2, Tc3 and Tc4, respectively, which satisfy relationships of Tc3<Tc2, Tc3<Tc4 and Tc3<Tc1, and the intermediate layer is a rare-earth-rich magnetic layer.Type: GrantFiled: December 5, 2001Date of Patent: August 3, 2004Assignee: Fujitsu LimitedInventors: Tsutomu Tanaka, Motonobu Mihara, Ken Tamanoi
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Publication number: 20040023072Abstract: A magneto-optical recording medium having a configuration such that information recorded can be read from a region smaller than a beam spot by applying an external magnetic field and directing a light beam in reproducing. The magneto-optical recording medium includes a magnetic recording layer for recording and holding information, a magnetic reproducing layer provided on one side of the magnetic recording layer on which the light beam is incident, a nonmagnetic layer provided on another side of the magnetic recording layer opposite to the magnetic reproducing layer, and a magnetic assist layer provided on the nonmagnetic layer. The magnetic assist layer has a coercive force smaller than an external magnetic field applied in recording or reproducing information.Type: ApplicationFiled: July 29, 2003Publication date: February 5, 2004Applicant: FUJITSU LIMITEDInventors: Toshio Sugimoto, Ken Tamanoi
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Publication number: 20030123169Abstract: A master medium for magnetic transfer includes a substrate having a concave portion formed in its surface corresponding to a pattern of recorded information to be transferred; a first perpendicular ferromagnetic layer deposited in the concave portion; and a second perpendicular ferromagnetic layer layered on the substrate surface and the first perpendicular ferromagnetic layer surface. The substrate surface and the first perpendicular ferromagnetic layer surface are flattened to form a single flat surface. In the master medium for magnetic transfer, a magnetic field change in a direction parallel to the substrate surface at a magnetization boundary of the first perpendicular ferromagnetic layer is steep. Since the influence of the change of an external magnetic field is reduced, it is possible to perform accurate transfer from the master medium for magnetic transfer to a slave medium for magnetic recording.Type: ApplicationFiled: March 20, 2002Publication date: July 3, 2003Applicant: FUJITSU LIMITEDInventors: Shingo Hamaguchi, Sumio Kuroda, Kazuyuki Ozaki, Ken Tamanoi, Koji Matsumoto