Patents by Inventor Tsutomu Tokunaga

Tsutomu Tokunaga 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: 9916788
    Abstract: An organic electroluminescent display device includes: a display unit in which pixels are arranged in rows and columns, the pixels each including an organic electroluminescent element, a drive transistor, and a capacitor; a power supply unit which generates a supply voltage; a gate drive unit which applies a reference supply voltage to the capacitor; and a control unit which carries the supply voltage from the power supply unit to the gate drive unit, wherein the gate drive unit includes a buffer amplifier circuit which suppresses a variable component of the supply voltage carried via the control unit to stabilize the reference supply voltage, and supplies the stabilized reference supply voltage to the pixel.
    Type: Grant
    Filed: December 19, 2014
    Date of Patent: March 13, 2018
    Assignee: JOLED INC.
    Inventors: Tsutomu Tokunaga, Noriyuki Iwakura, Takashi Iwami
  • Publication number: 20170069268
    Abstract: An organic electroluminescent display device includes: a display unit in which pixels are arranged in rows and columns, the pixels each including an organic electroluminescent element, a drive transistor, and a capacitor; a power supply unit which generates a supply voltage; a gate drive unit which applies a reference supply voltage to the capacitor; and a control unit which carries the supply voltage from the power supply unit to the gate drive unit, wherein the gate drive unit includes a buffer amplifier circuit which suppresses a variable component of the supply voltage carried via the control unit to stabilize the reference supply voltage, and supplies the stabilized reference supply voltage to the pixel.
    Type: Application
    Filed: December 19, 2014
    Publication date: March 9, 2017
    Applicant: JOLED INC.
    Inventors: Tsutomu TOKUNAGA, Noriyuki IWAKURA, Takashi IWAMI
  • Patent number: 8269694
    Abstract: A method for driving a plasma display panel (PDP) that can increase dark contrast without causing erroneous discharges is provided. A unit display period is divided into a plurality of subfields. A reset process and a sustain process are performed in one of the subfields. In the reset process, a reset pulse is applied to row electrodes of the PDP to initialize each discharge cell to an emission mode (or non-emission mode). In the sustain process, a sustain discharge is repeatedly generated a number of times, corresponding to the number of times a sustain pulse is to be applied, in those discharge cells that are in the emission mode. In this case, a peak potential of the reset pulse is changed based on the number of those discharge cells that are maintained in the non-emission mode during the unit display period and the number of times the sustain pulse is to be applied in the sustain process in this subfield.
    Type: Grant
    Filed: September 10, 2008
    Date of Patent: September 18, 2012
    Assignee: Panasonic Corporation
    Inventors: Yuya Shiozaki, Hitoshi Fujimura, Kazuo Yahagi, Tsutomu Tokunaga
  • Publication number: 20120019571
    Abstract: In the display of an image having a large black area, the luminance of black level of the display image is reduced so as to enhance the contrast. In the display of an image having a small black area, an address discharge is caused stably. Thereby, the image display quality is enhanced. For this purpose, a specified-cell initializing subfield where a forced initializing waveform is applied to predetermined scan electrodes and a non-initializing waveform is applied to the other scan electrodes in the initializing period, and a selective initializing subfield where a selective initializing waveform is applied to all the scan electrodes in the initializing period are set. A specified-cell initializing field having the specified-cell initializing subfield and the plurality of selective initializing subfields is set. The rate of regions where the gradation values of luminance are less than a predetermined value on the image display surface is calculated as a black area.
    Type: Application
    Filed: April 2, 2010
    Publication date: January 26, 2012
    Applicant: PANASONIC CORPORATION
    Inventors: Yutaka Yoshihama, Tsutomu Tokunaga
  • Patent number: 7990345
    Abstract: A plasma display panel and a drive method therefor, which can enhance a representation capability when displaying a dark image. The plasma display panel includes fluorophor layers containing magnesium oxide. The drive method includes a reset step to initialize all the pixel cells into states of one of a light-up mode and a light-off mode, and an address step in which the pixel cells are caused to perform address discharges selectively in accordance with pixel data, which are successively executed in each of a head subfield and a second subfield within a one-field display period. In reset step, a voltage that sets row electrodes on one side, in the row electrode pairs as an anode and sets the column electrodes set as a cathode is applied between the row electrodes on the one side and the column electrodes.
    Type: Grant
    Filed: September 10, 2007
    Date of Patent: August 2, 2011
    Assignee: Panasonic Corporation
    Inventors: Shunsuke Itakura, Atsushi Hirota, Hai Lin, Tsutomu Tokunaga
  • Publication number: 20110169875
    Abstract: A plasma display panel and a drive method therefor, which can enhance a representation capability when displaying a dark image. The plasma display panel includes fluorophor layers containing magnesium oxide. The drive method includes a reset step to initialize all the pixel cells into states of one of a light-up mode and a light-off mode, and an address step in which the pixel cells are caused to perform address discharges selectively in accordance with pixel data, which are successively executed in each of a head subfield and a second subfield within a one-field display period. In reset step, a voltage that sets row electrodes on one side, in the row electrode pairs as an anode and sets the column electrodes set as a cathode is applied between the row electrodes on the one side and the column electrodes.
    Type: Application
    Filed: February 25, 2011
    Publication date: July 14, 2011
    Applicant: PANASONIC CORPORATION
    Inventors: Shunsuke ITAKURA, Atsushi HIROTA, Hai LIN, Tsutomu TOKUNAGA
  • Publication number: 20110169807
    Abstract: A plasma display panel and a drive method therefor, which can enhance a representation capability when displaying a dark image. The plasma display panel includes fluorophor layers containing magnesium oxide. The drive method includes a reset step to initialize all the pixel cells into states of one of a light-up mode and a light-off mode, and an address step in which the pixel cells are caused to perform address discharges selectively in accordance with pixel data, which are successively executed in each of a head subfield and a second subfield within a one-field display period. In reset step, a voltage that sets row electrodes on one side, in the row electrode pairs as an anode and sets the column electrodes set as a cathode is applied between the row electrodes on the one side and the column electrodes.
    Type: Application
    Filed: February 25, 2011
    Publication date: July 14, 2011
    Applicant: PANASONIC CORPORATION
    Inventors: Shunsuke ITAKURA, Atsushi HIROTA, Hai LIN, Tsutomu TOKUNAGA
  • Publication number: 20110169876
    Abstract: A plasma display panel and a drive method therefor, which can enhance a representation capability when displaying a dark image. The plasma display panel includes fluorophor layers containing magnesium oxide. The drive method includes a reset step to initialize all the pixel cells into states of one of a light-up mode and a light-off mode, and an address step in which the pixel cells are caused to perform address discharges selectively in accordance with pixel data, which are successively executed in each of a head subfield and a second subfield within a one-field display period. In reset step, a voltage that sets row electrodes on one side, in the row electrode pairs as an anode and sets the column electrodes set as a cathode is applied between the row electrodes on the one side and the column electrodes.
    Type: Application
    Filed: February 25, 2011
    Publication date: July 14, 2011
    Applicant: PANASONIC CORPORATION
    Inventors: Shunsuke ITAKURA, Atsushi HIROTA, Hai LIN, Tsutomu TOKUNAGA
  • Patent number: 7965259
    Abstract: A plasma display device in which a sustain pulse having a leading period is applied between row electrodes forming each row electrode pair by a number of times previously determined for each subfield, in a sustain period, and a length of the leading period of the sustain pulse is set in accordance with an accumulated light emission time or an accumulated use time of the plasma display panel.
    Type: Grant
    Filed: November 3, 2006
    Date of Patent: June 21, 2011
    Assignee: Panasonic Corporation
    Inventors: Masatsugu Onizuka, Motofumi Ikeda, Yoshichika Sato, Tsutomu Tokunaga
  • Patent number: 7927243
    Abstract: A stock rubber is provided with chopped aramid fibers and chopped polyester fibers blended in the rubber component, which is EPDM. The chopped polyester fibers are longer than the chopped aramid fibers. A transmission V-belt is obtained and molded from the stock rubber. When molding, the chopped aramid fibers and the chopped polyester fibers are oriented in a width direction of a belt body of the V-belt.
    Type: Grant
    Filed: August 8, 2003
    Date of Patent: April 19, 2011
    Assignee: The Gates Corporation
    Inventors: Yoshitaka Sato, Masami Sato, Tsutomu Tokunaga, Satoshi Furukawa
  • Patent number: 7852296
    Abstract: A plasma display device in which at least one of a first sustain pulse having a first leading period and a second sustain pulse having a second leading period shorter than the first leading period is applied between row electrodes forming each row electrode pair by a number of times previously determined for each subfield, in a sustain period, and an application ratio between the first sustain pulse and the second sustain pulse in the sustain period of each subfield is changed in accordance with a luminance level of a video signal.
    Type: Grant
    Filed: September 8, 2006
    Date of Patent: December 14, 2010
    Assignee: Panasonic Corporation
    Inventors: Yoshichika Sato, Tsutomu Tokunaga, Motofumi Ikeda, Masatsugu Onizuka
  • Patent number: 7847758
    Abstract: A plasma display panel driving method in which a reset step and an address step are sequentially executed in the first subfield and second subfield of each field. A microemission step is executed in the first subfield for generating a microemission discharge between ones of the row electrodes and the column electrodes in display cells in the ON mode by applying a voltage for using the ones of the row electrodes as the anode and the column electrodes as the cathode, between the electrodes immediately after the address step. Moreover, in the microemission step, a potential lower than the voltage generated when applying a sustain pulse is respectively applied to the ones and the others of the row electrodes while applying a voltage as described above between the ones of the row electrodes and the column electrodes.
    Type: Grant
    Filed: October 25, 2007
    Date of Patent: December 7, 2010
    Assignee: Panasonic Corporation
    Inventors: Shunsuke Itakura, Tsutomu Tokunaga
  • Publication number: 20100245303
    Abstract: A plasma display device in which a sustain pulse having a leading period is applied between row electrodes forming each row electrode pair by a number of times previously determined for each subfield, in a sustain period, and a length of the leading period of the sustain pulse is set in accordance with an accumulated light emission time or an accumulated use time of the plasma display panel.
    Type: Application
    Filed: June 10, 2010
    Publication date: September 30, 2010
    Inventors: Masatsugu ONIZUKA, Motofumi Ikeda, Yoshichika Sato, Tsutomu Tokunaga
  • Patent number: 7733305
    Abstract: There are provided a plasma display device in which dark contrast can be enhanced without deteriorating an image quality and a method of driving a plasma display panel. In a case of driving a plasma display device in which a magnesium oxide layer containing a magnesium oxide crystal to be excited by the irradiation of an electron beam and performing a cathode luminescence having a peak in a wavelength range of 200 to 300 nm by a sub-field method, in order to initialize all display cells, reset discharge is caused in each of the display cells in M sub-fields of N consecutive sub-fields (0<M<N).
    Type: Grant
    Filed: May 17, 2005
    Date of Patent: June 8, 2010
    Assignee: Panasonic Corporation
    Inventors: Masaru Nishimura, Tsutomu Tokunaga, Kazuaki Sakata, Atsushi Hirota, Hai Lin
  • Patent number: 7688287
    Abstract: A plasma display apparatus includes a plasma display panel. Pulse voltage values and/or pulse widths of a variety of drive pulses that are applied to the plasma display panel are adjusted in accordance with the accumulated usage time of the plasma display panel.
    Type: Grant
    Filed: September 23, 2005
    Date of Patent: March 30, 2010
    Assignee: Panasonic Corporation
    Inventors: Tsutomu Tokunaga, Yoshichika Sato, Nobuhiko Saegusa
  • Patent number: 7633465
    Abstract: A plasma display apparatus and a driving method of a plasma display panel which can improve a gradation expressing ability at low luminance. A magnesium oxide layer containing a magnesium oxide crystal which is excited by irradiation of an electron beam and performs a cathode luminescence light emission having a peak in a wavelength range of 200 to 300 nanometers is provided in each of display cells formed on the plasma display panel. When driving for a plurality of subfields having different luminance weights is performed, a sustaining discharge is caused only once in the subfield having the minimum luminance weight.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: December 15, 2009
    Assignee: Panasonic Corporation
    Inventors: Kazuaki Sakata, Masaru Nishimura, Atsushi Hirota, Tsutomu Tokunaga, Hai Lin
  • Publication number: 20090231237
    Abstract: A method for driving a plasma display panel (PDP) that can increase dark contrast without causing erroneous discharges is provided. A unit display period is divided into a plurality of subfields. A reset process and a sustain process are performed in one of the subfields. In the reset process, a reset pulse is applied to row electrodes of the PDP to initialize each discharge cell to an emission mode (or non-emission mode). In the sustain process, a sustain discharge is repeatedly generated a number of times, corresponding to the number of times a sustain pulse is to be applied, in those discharge cells that are in the emission mode. In this case, a peak potential of the reset pulse is changed based on the number of those discharge cells that are maintained in the non-emission mode during the unit display period and the number of times the sustain pulse is to be applied in the sustain process in this subfield.
    Type: Application
    Filed: September 10, 2008
    Publication date: September 17, 2009
    Applicant: PIONEER CORPORATION
    Inventors: Yuya SHIOZAKI, Hitoshi Fujimura, Kazuo Yahagi, Tsutomu Tokunaga
  • Patent number: 7522128
    Abstract: A plasma display device having a plasma display panel in which, each display cell contains a magnesium oxide layer including magnesium oxide crystals that are excited by an electron beam to emit cathode luminescence light having a peak in a wavelength range of 200 to 300 nm. In an addressing period, a row electrode driving circuit applies a scanning pulse to one row electrodes of row electrode pairs in turn, while a column electrode driving circuit supplies column electrodes with data pulses corresponding to one row electrode which is applied with the scanning pulse.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: April 21, 2009
    Assignee: Pioneer Corporation
    Inventors: Tsutomu Tokunaga, Masaru Nishimura, Kazuaki Sakata, Atsushi Hirota, Hai Lin
  • Patent number: 7463220
    Abstract: A plasma display device and a method of driving a plasma display panel are provided for improving the contrast without degrading the image quality. Each of display cells formed on the plasma display panel has a magnesium oxide layer containing magnesium oxide crystals. The magnesium oxide crystals are excited by an electron beam irradiated thereto and emit cathode luminescence light having a peak in a wavelength range of 200 to 300 nm. In order to trigger a rest discharge in all the display cells, each row electrode pair of the plasma display panel is applied with a reset pulse which has a particular pulse waveform. The voltage value of this reset pulse slowly changes over time to reach a peak voltage value.
    Type: Grant
    Filed: April 21, 2005
    Date of Patent: December 9, 2008
    Assignee: Pioneer Corporation
    Inventors: Kazuaki Sakata, Masaru Nishimura, Atsushi Hirota, Tsutomu Tokunaga, Hai Lin
  • Publication number: 20080284684
    Abstract: A plasma display device and a method for driving the plasma display device are provided, wherein deterioration in image quality in a period immediately after power-on can be restrained while improving dark contrast. When driving a PDP, by applying various drive pulses, that includes a phosphor layer containing a secondary electron emissive material in respective discharge cells, drive pulses having different pulse waveforms are generated in a period from power-on of the plasma display device to after a lapse of a predetermined period of time, and in a period after a lapse of the predetermined period of time.
    Type: Application
    Filed: May 13, 2008
    Publication date: November 20, 2008
    Applicant: Pioneer Corporation
    Inventors: Mitsuhiro ISHIZUKA, Mitsuyoshi Makino, Hajime Homma, Koji Hashimoto, Masanori Ishihara, Tsutomu Tokunaga, Tatsuya Sugimoto