Patents by Inventor Akihiko Iwata
Akihiko Iwata 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: 20020092832Abstract: Charge accumulated in a capacitor is used to allow a processing current to flow between a target and an electrode. When a diode is turned on, a first dc power supply is used to allow the processing current to flow between the target and the electrode. In this state, after a lapse of a predetermined time, the current supply using the first dc power supply is stopped, and an induced electromotive voltage, induced by two floating reactors, is used to rapidly drop the processing current flowing between the target and the electrode, while charging the capacitor.Type: ApplicationFiled: May 3, 2001Publication date: July 18, 2002Inventors: Takashi Hashimoto, Akihiro Suzuki, Taichirou Tamida, Akihiko Iwata, Yoshikazu Tsunoda, Hiroyuki Ooguro, Yoshikazu Ukai
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Publication number: 20020070687Abstract: A gas discharge lamp lighting device comprises a DC/DC converter (2) for adjusting electric power supplied from a power supply so as to generate and output a DC voltage, and an FET (5) electrically connected to the DC/DC converter (2), for converting the DC voltage from the DC/DC converter (2) to an AC voltage to be supplied to a gas discharge lamp (12). A control unit (14) brings the gas discharge lamp (12) to an electrode heating state in which both electrodes of the gas discharge lamp (12) are heated after supplying the AC voltage to the gas discharge lamp. The control unit (14) controls an amount of energy to be supplied to the gas discharge lamp (12) placed in the electrode heating state according to a voltage across the gas discharge lamp. The control unit (14) brings the gas discharge lamp (12) to an AC discharging state in which an AC current flows through the gas discharge lamp (12) after the amount of energy has been supplied to the gas discharge lamp (12).Type: ApplicationFiled: May 24, 2001Publication date: June 13, 2002Inventors: Takahiro Urakabe, Akihiko Iwata, Hidehiko Kinoshita
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Patent number: 6400344Abstract: The present invention relates to a technique for driving a surface discharge type plasma display panel, and more particularly, it is an object of the present invention to freely perform setting without increasing a rating required for an IC having an address driver when a high voltage is to be output from an address electrode for a priming discharge period and a sustain discharge period. In order to attain the above-mentioned object, if the same voltage is simultaneously output to all address electrodes switches are turned off and on in a circuit respectively and a cathode of a diode and an anode of a diode are conducted. Then, the switches are forcedly turned off and on, respectively. In a circuit switches are turned on and off respectively and a voltage Va2 is substantially applied to all the address electrodes through the diode.Type: GrantFiled: December 13, 1999Date of Patent: June 4, 2002Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yoshikazu Tsunoda, Akihiko Iwata, Takahiro Urakabe, Takashi Hashimoto, Jun Someya, Takahito Nakanishi
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Publication number: 20020060205Abstract: The electric discharge machining apparatus comprises a wire electrode for machining a workpiece, and a first voltage applying unit for applying a voltage pulse. The voltage pulse is such that it has a rise time longer than a discharge formative time lag when a rectangular voltage pulse is applied when a distance between the workpiece and the wire is an average value in machining and rises up to the same voltage value as the rectangular voltage pulse.Type: ApplicationFiled: May 4, 2001Publication date: May 23, 2002Inventors: Taichiro Tamida, Takashi Hashimoto, Akihiro Suzuki, Akihiko Iwata, Atsushi Taneda
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Publication number: 20020057540Abstract: Switching elements of self-quenching function are connected in series to constitute a semiconductor switching device. A snubber circuit comprising the first diode, the first capacitor and a non-linear circuit is connected in parallel to the respective semiconductor switching element. In the snubber circuit, the first diode and the first capacitor are connected in series, and the non-linear circuit is connected in parallel to the first capacitor. The non-linear circuit comprises a impedance element, a Zener diode, and a controlling semiconductor element and draws current through the controlling semiconductor element when applied voltage exceeds the Zener voltage of the Zener diode. Said Zener voltage is larger than and has minimum latitude to divided voltage of the semiconductor element under an accident in power system.Type: ApplicationFiled: November 8, 2001Publication date: May 16, 2002Applicant: Mitsubishi Denki Kabushiki KaishaInventors: Hiroshi Ito, Akihiko Iwata, Akihiro Suzuki
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Patent number: 6369781Abstract: A sustain discharge which is performed a specified number of times to obtain a predetermined luminance includes a first discharge mainly induced by externally-applied voltage and a second discharge mainly induced by wall charges, and an assistant pulse is applied in a direction to increase the second discharge. That allows an improvement in efficiency of an AC-PDP.Type: GrantFiled: October 1, 1998Date of Patent: April 9, 2002Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Takashi Hashimoto, Akihiko Iwata
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Publication number: 20020008680Abstract: A sustain discharge which is performed a specified number of times to obtain a predetermined luminance includes a first discharge mainly induced by externally-applied voltage and a second discharge mainly induced by wall charges, and an assistant pulse is applied in a direction to increase the second discharge. That allows an improvement in efficiency of an AC-PDP.Type: ApplicationFiled: October 1, 1998Publication date: January 24, 2002Inventors: TAKASHI HASHIMOTO, AKIHIKO IWATA
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Patent number: 6304475Abstract: A laser power supply apparatus supplies AC power to a gas contained in a laser device by way of a pair of dielectric layers, without having to use a transformer to form a high-frequency discharge in a gas to excite the gas, to cause the laser device to radiate. The laser power supply apparatus includes an inverter having arms, each arm including high-speed semiconductor switches connected in series, for directly converting a DC high voltage from a DC power supply to a series of AC output pulses having a much higher AC voltage than the DC high voltage and supplied to the laser device by simultaneously turning on and off those high-speed semiconductor switches in each of the arms, and for furnishing the series of AC output pulses to the laser device at a pair of output terminals.Type: GrantFiled: February 18, 1999Date of Patent: October 16, 2001Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Akihiko Iwata, Junichi Nishimae, Masaaki Tanaka, Takashi Kumagai, Masato Matsubara
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Publication number: 20010017259Abstract: There is provided an electrolysis gas converter, which prevents excessive gas generation and can maintain a constant amount of gas conversion even if outside air conditions such as humidity changes. The converter, which provides DC current to a jointed electrochemical device 8 comprising a solid polymer electrolytic film 3 between an anode 1 and a cathode 2 having a catalytic layer on a base substrate of conductive porous material, comprises means 11 and 17 which provide a fixed current to the jointed electrochemical device 8.Type: ApplicationFiled: February 23, 2001Publication date: August 30, 2001Applicant: MITSUBISHI DENKI KABUSHIKI KAISHAInventors: Akira Ikeda, Akihiko Iwata, Shigeo Ueguri, Yoshikazu Tsunoda
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Publication number: 20010017605Abstract: In a reset period, through applying a rectangular pulse (Pya) of positive polarity to an electrode (Y) and applying a CR pulse (Pxa) of negative polarity to an electrode X, a full lighting pulse is applied between the electrodes (X and Y). The application of the voltage is stopped before a CR pulse (Pxc) reaches a final potential, to generate the pulse (Pxa). A full erase pulse (Pxb) made of a CR pulse having a polarity reverse to that of the pulse (Pxa) is applied to the electrode (X). An erase operation reverses the polarity of wall charges accumulated by a full lighting to effectively perform a potential control operation. The potential control pulse (Pxc) is applied to the electrode (X) to generate a discharge, and the state of the wall charges in a discharge cell is controlled by the discharge to generate an optimal amount of wall charges for a subsequent addressing discharge. The final voltage of the pulse (Pxc) is set equal to a voltage (−Vxg) of an address pulse (Pa).Type: ApplicationFiled: February 14, 2001Publication date: August 30, 2001Applicant: MITSUBISHI DENKI KABUSHIKI KAISHAInventors: Takashi Hashimoto, Takahiro Urakabe, Akihiko Iwata, Yoshikazu Tsunoda, Takayoshi Nagai
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Patent number: 6208084Abstract: A wall-voltage generation period is provided once in every several tens or hundreds of frames. A wall voltage (broken line) generated in the wall-voltage generation period does no disappear irrespective of the presence or absence of discharge emission. The presence or absence of discharge emission is controlled by varying the baseline of a voltage across electrodes (solid line) depending on variations in an address voltage (Va) during a display period. The number of priming reset discharges which has been necessary at least once in each frame can be reduced.Type: GrantFiled: December 1, 1999Date of Patent: March 27, 2001Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Takahiro Urakabe, Takashi Hashimoto, Akihiko Iwata
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Patent number: 6184662Abstract: A pulsed power supply device in which a capacitor (23) having a charged voltage is discharged quickly upon closure of a switch (24). First and second series circuits (51, 52) are connected to each other in series and provided between the output terminals of a DC voltage source (2). The first series circuit (51) is a series circuit of a first reactor (14) and a first forward-direction diode (15), and the second series circuit (52) is a series circuit of a second forward-direction diode (16) and a switch (24). A third series circuit (53) that is a series circuit of a capacitor (23), a second reactor (25), and a discharge tube (9) is connected in parallel to the second series circuit (52). Upon closure of the switch (24), the discharge tube emits light and, on the other hand, the capacitor (23) is discharged to produce an oscillation current, whereby a voltage develops across the capacitor (23) in the polarity opposite to the polarity at the time of the initial charging.Type: GrantFiled: October 26, 1999Date of Patent: February 6, 2001Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Masataka Yabuuchi, Akihiko Iwata
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Patent number: 5452317Abstract: A metal vapor laser apparatus is provided with a buffer gas and a laser medium are enclosed in a tube and the gas is utilized as an excitation or ionization medium in the tube. The metal vapor laser apparatus comprises molecules consisting of a plurality of elements and mixed by at least 0.1% in the gas enclosed in the tube and a gas having a molecular weight lighter than that of neon mixed by at least 0.1% in the gas enclosed in the tube.Type: GrantFiled: September 22, 1994Date of Patent: September 19, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yoichiro Tabata, Kazuhiko Hara, Akihiko Iwata, Shigeo Ueguri, Hiroshi Masuda, Yoshibumi Minowa
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Patent number: 5305338Abstract: A switch device used for a laser device, includes series-parallel connected switch elements or modules. The switch elements or modules are simultaneously turned on by trigger signals from trigger circuits. The transmission lines for connecting the trigger circuits to respective switch elements are equal to one another in length. A protecting circuit is provided for the switch elements, and indicators are provided for indicating the shortcircuit of the switch elements. In the switch device, the number of wires for the switch elements is made small and heat generated from the switch elements is effectively radiated. The modules are easily stacked, and firmly connected to a control unit for controlling the switch elements. A discharge excited laser device using the switch device has a high efficiency and a long lifetime and is reliable.Type: GrantFiled: September 10, 1991Date of Patent: April 19, 1994Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hitoshi Wakata, Akihiro Suzuki, Kenyu Haruta, Haruhiko Nagai, Akihiko Iwata, Shinji Murata, Isamu Tanakura, Tomohiro Sasagawa, Yuito Kimura
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Patent number: 5258994Abstract: A discharge-excited laser apparatus includes a pair of discharge electrodes extending in a direction of an optical axis; a plurality of charging capacitors charged by a power source; a plurality of peaking capacitors arranged in parallel in a longitudinal direction of the discharge electrodes and receiving energy accumulated in the charging capacitors; and a plurality of semiconductor switches arranged with conductive plates in the longitudinal direction of the discharge electrodes and connected in series and in parallel to the peaking capacitors. The construction of the semiconductor switches enables uniform shift of the energy in the charging capacitors to the peaking capacitors and reduction of inductance of a loop for capacity shifting.Type: GrantFiled: June 19, 1991Date of Patent: November 2, 1993Assignee: Mitsubishi Denki K.K.Inventors: Kenyu Haruta, Akihiro Suzuki, Akihiko Iwata, Yasushi Minamitani, Hitoshi Wakata, Tomohiro Sasagawa, Takashi Kumagai
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Patent number: 5243230Abstract: A pulse generator circuit which comprises a power supply source for outputting a high voltage signal. A first capacitor is charged with the high voltage signal output by the power supply source. A load device is supplied with the high voltage signal charged in the first capacitor. A semiconductor switch together with the first capacitor and the load constitute a closed loop. A first diode is inserted between the power supply source and the closed loop. A second diode is inserted in a closed loop and operates to suppress electrical vibrations. A second diode may have an opposite polarity to that of the first diode. A snubber circuit may also be inserted in parallel across the second diode.Type: GrantFiled: March 30, 1992Date of Patent: September 7, 1993Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiroshi Itou, Akihiko Iwata, Tatsuki Okamoto, Yoshihiro Ueda, Yoichiro Tabata
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Patent number: 5148318Abstract: An optical pulse waveform shaper capable of providing an optical pulse waveform of a desired intensity distribution with little loss. The optical pulse beam split by a beam splitter is directed into the beam splitter with a phase difference to combine with the transmitted optical pulse beam. The phase difference is controllable. The optical pulse waveform shaper is applicable between a laser oscillator with different exciting conditions and an amplifier.Type: GrantFiled: January 30, 1989Date of Patent: September 15, 1992Assignee: Mitsubishi Denki K.K.Inventors: Tatsuki Okamoto, Shigeo Ueguri, Kazuhiko Hara, Akihiko Iwata, Yoshihiro Ueda
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Patent number: 5122674Abstract: In a pulse generator circuit for a laser unit etc., plural semiconductor switches arranged in matrix alignment on an outer surface of a first tube are connected in series and parallel with one another, and an end of each series-connection of the semiconductor switches is electrically connected to a second tube provided in coaxial alignment to the first tube, thereby realizing a synthetic semiconductor switch for switching high voltage and large current between the other end of the series-connection of the semiconductor switches and the second tube.Type: GrantFiled: December 4, 1990Date of Patent: June 16, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Hiroshi Itou, Akihiko Iwata, Tatsuki Okamoto, Yoshihiro Ueda, Shinji Murata, Takashi Kumagai, Yoichiro Tabata
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Patent number: 5115168Abstract: A power supply circuit for a magnetron adapted to supply microwave energy to an electrodeless discharge bulb is disclosed. The circuit includes a rectifier coupled across a commerical AC voltage source, a filter for smoothing the output of the rectifier, an inverter for converting the DC voltage supplied from the filter into a high frequency AC voltage, a step-up transformer for stepping up the high frequency AC voltage outputted from the inverter, and a rectifier which rectifies the high voltage AC output of the transformer into a unidirectional voltage which is supplied to the magnetron. The inverter switching is controlled by a pulse width modulation control circuit to maintain the magnetron output power at a predetermined level.Type: GrantFiled: November 20, 1990Date of Patent: May 19, 1992Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Isao Shoda, Hitoshi Kodama, Kazuo Magome, Akihiko Iwata, Kenji Yoshizawa, Masakazu Taki
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Patent number: 5053682Abstract: A power supply circuit for a magnetron adapted to supply microwave energy to an electrodeless discharge bulb is disclosed. The circuit includes a rectifier coupled across a commercial AC voltage source, a filter for smoothing the output of the rectifier, an inverter for converting the DC voltage supplied from the filter into a high frequency AC voltage, a step-up transformer for stepping up the high frequency AC voltage outputted from the inverter, and a rectifier which rectifies the high voltage AC output of the transformer into a unidirectional voltage which is supplied to the magnetron. The inverter switching is controlled by a pulse width modulation control circuit to maintain the magnetron output power at a predetermined level.Type: GrantFiled: November 20, 1990Date of Patent: October 1, 1991Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Isao Shoda, Hitoshi Kodama, Kazuo Magome, Akihiko Iwata, Kenji Yoshizawa