Patents by Inventor Tokuro Ozawa

Tokuro Ozawa 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: 8130176
    Abstract: The invention provides an electro-optical apparatus that can prevent a shift in a threshold voltage of an amorphous silicon transistor while driving an organic EL device in a pixel circuit including the amorphous silicon transistor. A characteristic-adjustment circuit can be provided, which has a function of returning a shift in the threshold voltage of the amorphous silicon transistor included in the pixel circuit to the original state.
    Type: Grant
    Filed: July 23, 2008
    Date of Patent: March 6, 2012
    Assignee: Seiko Epson Corporation
    Inventors: Toshiyuki Kasai, Yoichi Imamura, Tokuro Ozawa
  • Publication number: 20110291708
    Abstract: An electronic apparatus includes an electronic circuit including a driving transistor, an additional capacitive element and a first switch for controlling a connection between a circuit point and a control terminal and a driving circuit which controls the first switch to an off state and changes the potential of the control terminal such that the driving transistor transitions to an on state in a first period, controls the first switch to the on state so as to set the potential of the control terminal to an initial compensation value, in a second period, and controls the first switch to the on state and changes the driving potential from the first potential to the second potential such that the driving transistor transitions to the on state, in a third period.
    Type: Application
    Filed: May 25, 2011
    Publication date: December 1, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Tokuro OZAWA
  • Publication number: 20110292092
    Abstract: An electro-optical device includes a pixel circuit, and a driving circuit. The pixel circuit includes a driving transistor, a first capacitive element, an electro-optical element, and a switch. The driving circuit controls the switch to be turned off, varies a potential such that the driving transistor is turned on, during a first period, sets a potential at a control terminal to a compensation initial value by controlling the switch to be turned on, during a second period, supplies a grayscale potential corresponding to a designated grayscale, varies a driving potential such that the driving transistor is turned on, during a third period, and varies a voltage between the control terminal and a first terminal with the passage of time, during a fourth period.
    Type: Application
    Filed: May 25, 2011
    Publication date: December 1, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Tokuro OZAWA
  • Publication number: 20110292093
    Abstract: An electro-optical device includes a pixel circuit, and a driving circuit. The pixel circuit includes a driving transistor, an electro-optical element, a first capacitive element, a first switch, and a second switch. The driving circuit varies a potential at a control terminal during a first period, sets the potential at the control terminal to a compensation initial value during a second period, varies a driving potential from a first potential to a second potential such that the driving transistor is turned on during a third period, supplies a grayscale potential corresponding to a designated grayscale to the signal line and controls the second switch to be turned on during a fourth period, and varies a voltage between the control terminal and a first terminal with the passage of time during a fifth period.
    Type: Application
    Filed: May 25, 2011
    Publication date: December 1, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventor: Tokuro OZAWA
  • Publication number: 20110181585
    Abstract: A semiconductor device includes: a first transistor which is electrically connected between a capacitive element and a data line; a second transistor which is electrically connected between the first transistor and the capacitive element; and a driving unit. The driving unit drives the first and second transistors so that when the data voltage is applied to the capacitive element, both the first and second transistors are turned on, the second transistor is temporarily turned off, after a timing at which both the first and second transistors are turned on, and then turned on again, and the first transistor is turned off at the timing at which the second transistor is temporarily turned off or after the timing and before the second transistor is turned on again.
    Type: Application
    Filed: January 25, 2011
    Publication date: July 28, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Tokuro OZAWA, Takashi SATO
  • Publication number: 20110063275
    Abstract: The invention provides an electro-optical device having circuits for driving electro-optical elements, such as organic EL elements, and a driving device, which can employ driving elements having low driving ability, such as ?-TFTs. By providing a charge storage capacitor between the source electrode and the gate electrode of a driving transistor which is between power sources, the electro-optical device can allow the driving transistor to control a driving current, even when an electro-optical element is connected to the source side of the driving transistor. In addition, driving data can be stored in the charge storage capacitor by applying a predetermined voltage to the source electrode of the driving transistor.
    Type: Application
    Filed: November 19, 2010
    Publication date: March 17, 2011
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Yoichi IMAMURA, Toshiyuki KASAI, Tokuro OZAWA
  • Patent number: 7855706
    Abstract: Provided is a method of driving an electro-optical element having a first electrode, a second electrode, and an electro-optical material provided between the first electrode and the second electrode and having optical characteristics which vary in accordance with an applied voltage, including: applying a fixed voltage to the first electrode and applying a data voltage according to a gray scale level to be displayed to the second electrode in a first period; applying the data voltage to the first electrode and applying the fixed voltage to the second electrode in a second period; and alternately repeating the driving in the first period and the driving in the second period.
    Type: Grant
    Filed: July 23, 2007
    Date of Patent: December 21, 2010
    Assignee: Seiko Epson Corporation
    Inventor: Tokuro Ozawa
  • Patent number: 7714810
    Abstract: The invention provides an electro-optical apparatus that can prevent a shift in a threshold voltage of an amorphous silicon transistor while driving an organic EL device in a pixel circuit including the amorphous silicon transistor. A characteristic-adjustment circuit can be provided, which has a function of returning a shift in the threshold voltage of the amorphous silicon transistor included in the pixel circuit to the original state.
    Type: Grant
    Filed: May 12, 2004
    Date of Patent: May 11, 2010
    Assignee: Seiko Epson Corporation
    Inventors: Toshiyuki Kasai, Yoichi Imamura, Tokuro Ozawa
  • Publication number: 20100079357
    Abstract: To reduce the time for writing a voltage onto a gate of a driving transistor. In an initialization period, a node B is fixed to an initial voltage VINI, transistors are turned on, and a current flows into an OLED element, such that a voltage according to the current is held at the node A. Thereafter, the transistors are sequentially turned off, such that a threshold voltage of a driving transistor is held at the node A. In a writing period, a transistor is turned on and a data signal X-j is supplied, such that a voltage of the node B varies by the amount according to the current flowing into the OLED element. The voltage of the node A varies from the threshold voltage by the amount which is obtained by dividing the voltage variation by a capacitance ratio. In a light-emitting period, the transistor is turned on, such that a current according to the voltage of the node A flows into the OLED element.
    Type: Application
    Filed: December 4, 2009
    Publication date: April 1, 2010
    Applicant: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Toshiyuki Kasai, Eiji Kanda, Ryoichi Nozawa
  • Patent number: 7649515
    Abstract: To reduce the time for writing a voltage onto a gate of a driving transistor. In an initialization period, a node B is fixed to an initial voltage VINI, transistors are turned on, and a current flows into an OLED element, such that a voltage according to the current is held at the node A. Thereafter, the transistors are sequentially turned off, such that a threshold voltage of a driving transistor is held at the node A. In a writing period, a transistor is turned on and a data signal X-j is supplied, such that a voltage of the node B varies by the amount according to the current flowing into the OLED element. The voltage of the node A varies from the threshold voltage by the amount which is obtained by dividing the voltage variation by a capacitance ratio. In a light-emitting period, the transistor is turned on, such that a current according to the voltage of the node A flows into the OLED element.
    Type: Grant
    Filed: March 29, 2005
    Date of Patent: January 19, 2010
    Assignee: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Toshiyuki Kasai, Eiji Kanda, Ryoichi Nozawa
  • Publication number: 20090273578
    Abstract: A sensing circuit having a first substrate, a second substrate, a layer of dielectric material, a first electrode, a second electrode and an electrostatic capacitance detection unit is provided. The second substrate faces the first substrate. The dielectric material is held between the first substrate and the second substrate. The first electrode and the second electrode are arranged between the dielectric material and the first substrate. The electrostatic capacitance detection unit is configured to produce a detection signal having an amplitude according to a value of capacitance formed between the first electrode and the second electrode through the dielectric material.
    Type: Application
    Filed: April 21, 2009
    Publication date: November 5, 2009
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Eiji KANDA, Yasushi TSUCHIYA, Tokuro OZAWA, Toshiharu MATSUSHIMA
  • Patent number: 7601943
    Abstract: A method of manufacturing an electro-optical device having a plurality of unit regions arranged in a matrix on a surface of a flat plate-shaped base substrate. In each of the plurality of unit regions, a pixel electrode is formed. A counter electrode is formed on an opposite side to the base substrate with respect to the pixel electrodes. In pixel regions, which are first unit regions constituting a predetermined image among the plurality of unit regions, OLED elements are selectively formed. The OLED elements are interposed between the respective pixel electrodes and the counter electrode. In non-pixel regions, which are second unit regions other than the first unit regions among the plurality of unit regions, insulators are formed. The insulators are interposed between the respective pixel electrodes and the counter electrode.
    Type: Grant
    Filed: January 3, 2008
    Date of Patent: October 13, 2009
    Assignee: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Ayae Endo, Ryoichi Nozawa
  • Patent number: 7592983
    Abstract: An electro-optical device includes a plurality of pixel circuits that are disposed to correspond to intersections of a plurality of scanning lines and a plurality of data lines, a scanning line driving circuit that sequentially selects the plurality of scanning lines to apply a selection voltage to the selected scanning line, a data line driving circuit that applies any one of an on voltage and an off voltage to the plurality of data lines in accordance with gray-scale levels of pixel circuits corresponding to intersections of the data lines and the selected scanning line by the scanning line driving circuit, and a signal supply circuit that supplies a driving signal, of which the level periodically changes, to a signal supply line.
    Type: Grant
    Filed: October 5, 2005
    Date of Patent: September 22, 2009
    Assignee: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Ryoichi Nozawa
  • Publication number: 20090184986
    Abstract: The invention provides an electro-optical apparatus that can prevent a shift in a threshold voltage of an amorphous silicon transistor while driving an organic EL device in a pixel circuit including the amorphous silicon transistor. A characteristic-adjustment circuit can be provided, which has a function of returning a shift in the threshold voltage of the amorphous silicon transistor included in the pixel circuit to the original state.
    Type: Application
    Filed: July 23, 2008
    Publication date: July 23, 2009
    Applicant: Seiko Epson Corporation
    Inventors: Toshiyuki Kasai, Yoichi Imamura, Tokuro Ozawa
  • Publication number: 20090160840
    Abstract: To reduce time for writing a target voltage in the gate of a driving transistor. In a first period, a transistor 211 is switched on to allow a driving transistor 210 to function as a diode and transistors 212 and 213 are switched on to electrically connect the drain of the driving transistor 210 to a data line 112, to which an initial voltage is applied, such that the initial voltage is applied to the gate of the driving transistor 210. In a second period, a transistor 212 is switched off such that the gate of the driving transistor 210 is maintained to have an off voltage corresponding to the power source. In a third period, the transistor 211 is switched off such that the voltage of the data line 112 is converted into a grayscale voltage to maintain the gate of the driving transistor at the target voltage. In a fourth period, the driving transistor 210 flows the current corresponding to the maintained gate voltage to an OLED element 230.
    Type: Application
    Filed: February 11, 2009
    Publication date: June 25, 2009
    Applicant: SEIKO EPSON CORPORATION
    Inventors: Tokuro Ozawa, Ryoichi Nozawa
  • Patent number: 7508362
    Abstract: To reduce time for writing a target voltage in the gate of a driving transistor. In a first period, a transistor 211 is switched on to allow a driving transistor 210 to function as a diode and transistors 212 and 213 are switched on to electrically connect the drain of the driving transistor 210 to a data line 112, to which an initial voltage is applied, such that the initial voltage is applied to the gate of the driving transistor 210. In a second period, a transistor 212 is switched off such that the gate of the driving transistor 210 is maintained to have an off voltage corresponding to the power source. In a third period, the transistor 211 is switched off such that the voltage of the data line 112 is converted into a grayscale voltage to maintain the gate of the driving transistor at the target voltage. In a fourth period, the driving transistor 210 flows the current corresponding to the maintained gate voltage to an OLED element 230.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: March 24, 2009
    Assignee: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Ryoichi Nozawa
  • Publication number: 20080316151
    Abstract: The invention provides an electro-optical apparatus that can prevent a shift in a threshold voltage of an amorphous silicon transistor while driving an organic EL device in a pixel circuit including the amorphous silicon transistor. A characteristic-adjustment circuit can be provided, which has a function of returning a shift in the threshold voltage of the amorphous silicon transistor included in the pixel circuit to the original state.
    Type: Application
    Filed: July 23, 2008
    Publication date: December 25, 2008
    Applicant: Seiko Epson Corporation
    Inventors: Toshiyuki Kasai, Yoichi Imamura, Tokuro Ozawa
  • Patent number: 7463225
    Abstract: To increase a current value of a source line at the time of current programming. A device for driving an electro-optical panel in which a plurality of pixels each have an electro-optical element and active element means for selectively supplying electric charge to the electro-optical element through a source line in response to a write selection signal.
    Type: Grant
    Filed: November 23, 2004
    Date of Patent: December 9, 2008
    Assignee: Seiko Epson Corporation
    Inventor: Tokuro Ozawa
  • Patent number: 7460093
    Abstract: To reduce a time for applying a target voltage to a gate of a driving transistor. During an initializing period, both ends of a capacitive element become a short-circuited state by turning on transistors, so that node A and B becomes a voltage made by subtracting the threshold voltage Vthp of the driving transistor from a power source voltage VEL. During a writing period, the transistor is turned on and a data signal X-j is supplied to change the voltage at the node B as much as a voltage corresponding the current which is to flow into an OLED element. The node A is changed from the threshold voltage as much as the value obtained by dividing the voltage change by capacity ratio. During a light-emitting period, the transistor is turned on, so that the current corresponding to the voltage at the node A flows through the OLED element.
    Type: Grant
    Filed: March 29, 2005
    Date of Patent: December 2, 2008
    Assignee: Seiko Epson Corporation
    Inventors: Tokuro Ozawa, Eiji Kanda, Ryoichi Nozawa
  • Patent number: 7446739
    Abstract: To suppress an off leak current of a switching element arranged along a data line to control degradation of tonal gradation in an arrangement in which an organic electro-luminescent element OLED is driven using a current programming method, a first switching element is set to be in a non-conductive state and a second switching element is set to be in a conductive state during a normal mode. During a test mode, the first switching element is set to be in a conductive state while the second switching element is set to be in a non-conductive state.
    Type: Grant
    Filed: April 21, 2004
    Date of Patent: November 4, 2008
    Assignee: Seiko Epson Corporation
    Inventors: Hayato Nakanishi, Tokuro Ozawa, Takashi Miyazawa