Patents by Inventor Kazuo Okawa

Kazuo Okawa 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: 9392676
    Abstract: A discharge lamp lighting device includes: a DC power supply unit that outputs a DC current; an inverter that sequentially generates, from the DC current output from the DC power supply unit, a current pulse whose current direction alternately changes to supply the current pulse to a discharge lamp; and a control unit that controls operations of the DC power supply unit and the inverter to adjust a waveform of the current pulse to be supplied to the discharge lamp, wherein the control unit changes a pulse width of the current pulse every pulse.
    Type: Grant
    Filed: August 27, 2010
    Date of Patent: July 12, 2016
    Assignee: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Patent number: 8937436
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Grant
    Filed: May 11, 2012
    Date of Patent: January 20, 2015
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8558471
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Grant
    Filed: December 16, 2011
    Date of Patent: October 15, 2013
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8541955
    Abstract: Provided is an electric discharge lamp lighting device (10) including a control section (40) which performs first control operation for controlling at least the current value, frequency, duty ratio or waveform of a driving current (I) for driving an electric discharge lamp (90). The electric discharge lamp lighting device also includes a signal receiving section (50) for receiving a drive control signal (S) which can control at least the current value, frequency, duty ratio or waveform of the driving current (I) in mode different from the first control operation. The control section (40) performs second control operation for controlling at least the current value, frequency duty ratio or waveform of the driving current (I) based on the drive control signal (S), in the case where the signal receiving section (50) has received the drive control signal (S).
    Type: Grant
    Filed: December 25, 2008
    Date of Patent: September 24, 2013
    Assignee: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Publication number: 20120249011
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Application
    Filed: May 11, 2012
    Publication date: October 4, 2012
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Kentaro YAMAUCHI, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8264170
    Abstract: In at least one embodiment of the disclosure, a discharge lamp lighting device includes a discharge lamp driving unit that drives a discharge lamp by supplying an AC driving current to the discharge lamp. A memory unit is configured to store driving parameters for the AC driving current. A control unit is configured to control the discharge lamp driving unit based on the driving parameters stored in the memory unit. The driving parameters comprise a range of holding time values, each holding time value representing a time period in which the AC driving current is to be continuously maintained at a same polarity. Upon a predetermined time condition, the control unit selects one of the holding time values based on a predetermined probability and controls the discharge lamp driving unit based on the selected holding time value.
    Type: Grant
    Filed: February 2, 2010
    Date of Patent: September 11, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kazuo Okawa
  • Patent number: 8203280
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Grant
    Filed: December 5, 2008
    Date of Patent: June 19, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8167438
    Abstract: A light source device is provided. The light source device has: a discharge lamp that emits light by discharge in an interelectrode space between a first electrode and a second electrode; a main mirror arranged at the first electrode side that reflects light flux generated by the discharge in the interelectrode space so as to emit the light flux to an area to be illuminated; a sub-mirror arranged at the second electrode side facing opposite the main mirror that reflects the light flux from the interelectrode space toward the interelectrode space; and a driver that supplies alternating current to the first and the second electrodes, and changes duty ratio of the alternating current supplied to the first and the second electrodes in accordance with a predetermined pattern.
    Type: Grant
    Filed: December 5, 2008
    Date of Patent: May 1, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Publication number: 20120086923
    Abstract: To prevent biased consumption of electrodes in a discharge lamp and to prevent biased precipitation of the electrode material, a light source is provided. The light source device has a discharge lamp that emits light by discharge between a first electrode and a second electrode; and a driver that supplies alternating current to the first and the second electrodes so as to maintain the discharge, and changes duty ratio of the alternating current in accordance with predetermined pattern. The predetermined pattern includes a plurality of section periods for which the duty ratio maintains mutually different values for a predetermined period.
    Type: Application
    Filed: December 16, 2011
    Publication date: April 12, 2012
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Shigeyasu Soma
  • Patent number: 8102128
    Abstract: A driving method for a discharge lamp that lights by performing discharge between two electrodes while alternately switching a polarity of a voltage applied between the two electrodes includes: modulating an anode duty ratio, which is a ratio of an anode time for which one of the electrodes operates as an anode in one period of the polarity switching, by setting first and second periods with different anode duty ratios; and setting a first polarity switching period in the first period to be shorter than a second polarity switching period in the second period.
    Type: Grant
    Filed: March 16, 2009
    Date of Patent: January 24, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kentaro Yamauchi, Takeshi Takezawa, Kazuo Okawa
  • Patent number: 8089214
    Abstract: A driving method for a discharge lamp that lights by performing discharge between two electrodes while alternately switching a polarity of a voltage applied between the two electrodes includes: modulating an anode duty ratio, which is a ratio of an anode time for which one of the electrodes operates as an anode in one period of the polarity switching, within a predetermined range; and changing the predetermined range to make a maximum value of the modulated anode duty ratio higher than a maximum value of an initial anode duty ratio of the discharge lamp when a predetermined condition is satisfied.
    Type: Grant
    Filed: February 20, 2009
    Date of Patent: January 3, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kentaro Yamauchi, Takeshi Takezawa, Kazuo Okawa
  • Patent number: 8076861
    Abstract: A method for driving a discharge lamp that lights by performing discharge between two electrodes while alternately switching a polarity of a voltage applied between the two electrodes includes: modulating an anode duty ratio, which is a ratio of an anode time for which one of the electrodes operates as an anode in one period of the polarity switching, by setting first and second periods with different anode duty ratios; and setting the first period, in which the anode duty ratio is higher than that in the second period, longer than the second period in one modulation period, which includes the first and second periods and for which the modulation is performed, when a predetermined condition is satisfied.
    Type: Grant
    Filed: February 20, 2009
    Date of Patent: December 13, 2011
    Assignee: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kentaro Yamauchi, Takeshi Takezawa, Kazuo Okawa
  • Patent number: 8044613
    Abstract: A discharge lamp lighting device includes: a power control circuit outputting DC current; an AC conversion circuit generating and outputting discharge lamp driving AC current by inverting the polarity of the DC current at a predetermined timing; a control circuit performing an AC conversion control process of controlling a polarity inversion timing of the discharge lamp driving AC current on the AC conversion circuit and performing an interval current control process of controlling a current value of the DC current every polarity inversion timing interval on the power control circuit; a detection unit detecting a discharge lamp driving voltage at the time of normal lighting; a history information storage periodically storing history information of the detected discharge lamp driving voltage, a statistics processing unit statistically processing the stored history information every predetermined period; and a statistical information storage storing information having been subjected to the statistical process a
    Type: Grant
    Filed: March 10, 2009
    Date of Patent: October 25, 2011
    Assignee: Seiko Epson Corporation
    Inventors: Kazuo Okawa, Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa
  • Patent number: 7999490
    Abstract: A light source includes an arc tube having a first electrode and a second electrode that emit light by discharge between the electrodes, and a driving unit that supplies a current between the first electrode and the second electrode and can change at least a waveform of frequency and waveform of the supplied current. The driving unit can perform lighting drive of the arc tube, using a driving waveform formed by combining a first lighting waveform having a maximum current value at a part other than a half-cycle rear end of the waveform and a second lighting waveform having a maximum current value at the half-cycle rear end of the waveform.
    Type: Grant
    Filed: October 27, 2008
    Date of Patent: August 16, 2011
    Assignee: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kentaro Yamauchi, Takeshi Takezawa, Kazuo Okawa, Keishi Kimura
  • Patent number: 7999488
    Abstract: An ignition controller that controls ignition of a discharge lamp discharging and emitting light between a pair of electrodes provided therein, the controller includes: an ignition device that ignites the discharge lamp, and a controller that controls a drive of the ignition device, in which the controller includes: a pulse applying unit that applies a high pressure pulse to the pair of electrodes by the ignition device, a direct current applying unit for applying a direct current to the pair of electrodes for a first period after applying the high pressure pulse, and an alternating current applying unit for applying a first alternating current to the pair of electrodes for a second period after the first period.
    Type: Grant
    Filed: June 23, 2008
    Date of Patent: August 16, 2011
    Assignee: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Patent number: 7946715
    Abstract: A light source includes an discharge lamp including a first electrode and a second electrode emitting light by discharge between them, a drive unit performing a steady operation which supplies steady energy to the first and second electrodes and an initial operation which supplies energy to the first and second electrodes with an operation different from the steady operation before performing the steady operation, a determination unit determining states of the discharge lamp and a data storage unit storing plural initial power feeding conditions provided corresponding to states of the discharge lamp as examples of the initial operation and plural steady power feeding conditions provided corresponding to the states of the discharge lamp as examples of the steady operation, in which the drive unit performs the initial operation in any one of conditions selected from the plural initial power feeding conditions according to a determination result by the determination unit and performs the steady operation in any
    Type: Grant
    Filed: September 25, 2008
    Date of Patent: May 24, 2011
    Assignee: Seiko Epson Corporation
    Inventors: Kentaro Yamauchi, Tetsuo Terashima, Takeshi Takezawa, Kazuo Okawa, Keishi Kimura
  • Publication number: 20110095696
    Abstract: A discharge lamp lighting device includes: a DC power supply unit that outputs a DC current; an inverter that sequentially generates, from the DC current output from the DC power supply unit, a current pulse whose current direction alternately changes to supply the current pulse to a discharge lamp; and a control unit that controls operations of the DC power supply unit and the inverter to adjust a waveform of the current pulse to be supplied to the discharge lamp, wherein the control unit changes a pulse width of the current pulse every pulse.
    Type: Application
    Filed: August 27, 2010
    Publication date: April 28, 2011
    Applicant: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Patent number: 7923940
    Abstract: A method of generating a driving current supplied to a high pressure discharge lamp, including outputting a DC current, converting the DC current to an AC current having a predetermined frequency, generating a reference pulse which is asynchronous with the AC current, and superposing the first pulse and the second pulse to the AC current for producing the driving current.
    Type: Grant
    Filed: February 18, 2009
    Date of Patent: April 12, 2011
    Assignee: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Publication number: 20100277085
    Abstract: Provided is an electric discharge lamp lighting device (10) including a control section (40) which performs first control operation for controlling at least the current value, frequency, duty ratio or waveform of a driving current (I) for driving an electric discharge lamp (90). The electric discharge lamp lighting device also includes a signal receiving section (50) for receiving a drive control signal (S) which can control at least the current value, frequency, duty ratio or waveform of the driving current (I) in mode different from the first control operation. The control section (40) performs second control operation for controlling at least the current value, frequency duty ratio or waveform of the driving current (I) based on the drive control signal (S), in the case where the signal receiving section (50) has received the drive control signal (S).
    Type: Application
    Filed: December 25, 2008
    Publication date: November 4, 2010
    Applicant: Seiko Epson Corporation
    Inventor: Kazuo Okawa
  • Publication number: 20100201281
    Abstract: In at least one embodiment of the disclosure, a discharge lamp lighting device includes a discharge lamp driving unit that drives a discharge lamp by supplying an AC driving current to the discharge lamp. A memory unit is configured to store driving parameters for the AC driving current. A control unit is configured to control the discharge lamp driving unit based on the driving parameters stored in the memory unit. The driving parameters comprise a range of holding time values, each holding time value representing a time period in which the AC driving current is to be continuously maintained at a same polarity. Upon a predetermined time condition, the control unit selects one of the holding time values based on a predetermined probability and controls the discharge lamp driving unit based on the selected holding time value.
    Type: Application
    Filed: February 2, 2010
    Publication date: August 12, 2010
    Applicant: Seiko Epson Corporation
    Inventors: Tetsuo Terashima, Kazuo Okawa