Patents by Inventor Naoki Itokawa

Naoki Itokawa 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: 8207912
    Abstract: Sustain pulses are alternately applied to a pair of display electrodes of discharge cells provided in a plasma display panel (PDP) to generate a sustain discharge to display an image on the PDP. The sustain pulses include two-crests discharge voltage waveforms having a first maximum and second maximum values, in which discharges are generated twice in a half cycle. After applying a sustain pulse having a one-crest discharge voltage waveform to a pair of display electrodes, a predetermined number of sustain pulses of two-crests discharge voltage waveforms are consecutively applied. A time, from applying a second sustain pulse of a two-crests discharge voltage waveform to clamping a voltage of the second sustain pulse to the second maximum value, is made longer than a time, from applying a first sustain pulse of a two-crests discharge voltage waveform to clamping a voltage of the first sustain pulse to the second maximum value.
    Type: Grant
    Filed: November 12, 2008
    Date of Patent: June 26, 2012
    Assignee: Hitachi, Ltd.
    Inventors: Naoki Itokawa, Katsumi Ito, Masaki Kimura, Junichi Kumagai, Yasunobu Hashimoto, Tomokatsu Kishi
  • Patent number: 8115703
    Abstract: A method for driving a plasma display panel is provided in which wasteful power consumption is reduced and light emission efficiency is improved when the number of cells to be lighted is relatively small. The method includes classifying a display ratio into plural group ranges, selecting a suitable display pulse waveform for each group range, detecting the display ratio of an object to be displayed in a real display, and plural types of display pulses having different waveforms are used differently in accordance with the result of the detection. The display ratio means a ratio of the number of cells to be lighted to the number of cells of the screen.
    Type: Grant
    Filed: July 5, 2011
    Date of Patent: February 14, 2012
    Assignees: Hitachi Plasma Patent Licensing Co., Ltd., Fujitsu Hitachi Plasma Display Limited
    Inventors: Naoki Itokawa, Yoshiho Seo, Yasunobu Hashimoto, Tetsuya Sakamoto, Tomokatsu Kishi
  • Publication number: 20110267378
    Abstract: A method for driving a plasma display panel is provided in which wasteful power consumption is reduced and light emission efficiency is improved when the number of cells to be lighted is relatively small. The method includes classifying a display ratio into plural group ranges, selecting a suitable display pulse waveform for each group range, detecting the display ratio of an object to be displayed in a real display, and plural types of display pulses having different waveforms are used differently in accordance with the result of the detection. The display ratio means a ratio of the number of cells to be lighted to the number of cells of the screen.
    Type: Application
    Filed: July 5, 2011
    Publication date: November 3, 2011
    Applicants: HITACHI PLASMA DISPLAY LIMITED, HITACHI PLASMA PATENT LICENSING CO., LTD.
    Inventors: Naoki Itokawa, Yoshiho Seo, Yasunobu Hashimoto, Tetsuya Sakamoto, Tomokatsu Kishi
  • Publication number: 20110261047
    Abstract: A plasma display apparatus includes a plasma display panel having a plurality of sustain electrodes and a plurality of scan electrodes, a driver circuit to apply sustain pulses to the plurality of sustain electrodes and the plurality of scan electrodes to generate sustain discharges, and a control circuit to control the driver circuit such that a total light emitting pulse count defined as a total number of sustain pulses in one display frame is set equal to a predetermined pulse count defined as a function of a display load ratio, and such that the total light emitting pulse count is set lower than the predetermined pulse count upon detecting a predetermined condition, wherein the control circuit is configured to cause the driver circuit to selectively generate first sustain pulses with timing for clamping to a predetermined voltage being first timing and second sustain pulses with timing for clamping to the predetermined voltage being second timing, and configured to cause a ratio between a number of the fi
    Type: Application
    Filed: February 7, 2008
    Publication date: October 27, 2011
    Inventors: Junichi Kumagai, Naoki Itokawa, Katsumi Itou, Masaki Kimura
  • Patent number: 7995007
    Abstract: A method for driving a plasma display panel is provided in which wasteful power consumption is reduced and light emission efficiency is improved when the number of cells to be lighted is relatively small. The method includes classifying a display ratio into plural group ranges, selecting a suitable display pulse waveform for each group range, detecting the display ratio of an object to be displayed in a real display, and plural types of display pulses having different waveforms are used differently in accordance with the result of the detection. The display ratio means a ratio of the number of cells to be lighted to the number of cells of the screen.
    Type: Grant
    Filed: April 9, 2008
    Date of Patent: August 9, 2011
    Assignees: Hatachi Plasma Patent Licensing Co., Ltd., Hitachi Plasma Display Limited
    Inventors: Naoki Itokawa, Yoshiho Seo, Yasunobu Hashimoto, Tetsuya Sakamoto, Tomokatsu Kishi
  • Patent number: 7990341
    Abstract: A technique which enables improvement of luminance and reduction of consumption power in a sustain discharge driving of a four-electrode structure PDP, particularly, by devising driving method to Z electrodes. In this plasma display device, a sustain discharge by a method to apply a narrow pulse to the Z electrode and a method to apply a fixed potential to the Z electrode are switched according to a judgment of range of display load ratio in driving sustain discharge from a controller and driver to the PDP and used.
    Type: Grant
    Filed: July 26, 2005
    Date of Patent: August 2, 2011
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Naoki Itokawa, Tetsuya Sakamoto, Takayuki Kobayashi, Tomokatsu Kishi, Yasunobu Hashimoto
  • Patent number: 7911419
    Abstract: In a conventional method of driving a plasma display panel, for example, an auxiliary discharge is executed between an A electrode and a Y electrode to improve light-emission efficiency of a display discharge. However, since a phosphor layer is present between the A electrode and the Y electrode, the phosphor layer is exposed to a discharge, whereby there is a problem that its characteristic deteriorates. A method of driving a plasma display panel having a structure, in which at least three display electrodes X, Y, and Z used for a display discharge are provided to a display cell and no phosphor layer is formed between said display electrodes and a discharge space, the method comprising the steps of: varying a potential of at least one display electrode Z of said display electrodes during said display discharge; and making a potential of said at least one display electrode Z at a time of starting said display discharge different from that at a time of ending said display discharge.
    Type: Grant
    Filed: December 27, 2005
    Date of Patent: March 22, 2011
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Yasunobu Hashimoto, Tomokatsu Kishi, Tetsuya Sakamoto, Naoki Itokawa, Takayuki Kobayashi, Yoshimi Kawanami, Osamu Toyoda, Yasuhiko Kunii, Takahiro Takamori, Kunio Takayama
  • Patent number: 7808453
    Abstract: In a sustain operation in an ALIS PDP device, a combination in which a basic first waveform and a second waveform in which a discharge peak is separated are mixed is applied. In the combination, the probability that the second waveform occurs successively is sufficiently reduced to less than 20%, and the number of times of sustain discharges of various intensities is made equal in the lines to be driven. By this means, the 2L nonuniformity can be prevented, and the deterioration of Vsmin can be reduced.
    Type: Grant
    Filed: May 10, 2007
    Date of Patent: October 5, 2010
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Keishin Nagaoka, Yoshikazu Kanazawa, Naoki Itokawa
  • Patent number: 7737917
    Abstract: An interlace-type PDP is driven by an improved driving method so as to achieve a greater operating margin, higher resolution, and higher brightness. The interlace-type PDP is driven using odd and even frames in such a manner that the cells are grouped into cell groups such that each cell group includes two or three cells which are adjacent in a direction crossing the electrode pairs, and the cells are driven in units of cell groups. The grouping of cells is performed differently for even and odd frames such that, in one type of frame, locations of two or three cells grouped into each group are shifted by one cell, in the direction crossing the electrode pairs, from the locations of cells grouped together in the other type of frame.
    Type: Grant
    Filed: January 26, 2007
    Date of Patent: June 15, 2010
    Assignee: Hitachi, Ltd.
    Inventors: Yasunobu Hashimoto, Hajime Inoue, Yoshiho Seo, Naoki Itokawa
  • Patent number: 7667671
    Abstract: There is provided a plasma display device that has a first, a second, and a third electrodes, phosphors emitting a light depending on discharges generated by applying voltages of the first to third electrodes, and a drive circuit for applying a pulse to the third electrode in every time discharge light emission is generated by applying an alternating pulse between the first and second electrodes, and the time at which the pulse of the third electrode reaches 50% of its amplitude in the trailing edge takes place before the time of the first peak of the light emission waveform.
    Type: Grant
    Filed: January 27, 2006
    Date of Patent: February 23, 2010
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Tomokatsu Kishi, Naoki Itokawa, Takayuki Kobayashi, Yasunobu Hashimoto
  • Patent number: 7642991
    Abstract: A method for driving an AC type plasma display panel includes the steps of performing initialization at least once for each frame so as to clear binary setting of wall charge quantity in a screen by discharge except for micro discharge in which electrodes covered with a plurality of fluorescent materials become cathodes, and performing special initialization at frequency of once for M frames, where M=two or more, so as to erase unnecessary wall charge in the screen by discharge in which electrodes become cathodes and that is stronger than the discharge in the initialization.
    Type: Grant
    Filed: June 18, 2004
    Date of Patent: January 5, 2010
    Assignee: Hitachi Plasma Patent Licensing Co., Inc.
    Inventors: Yasunobu Hashimoto, Tadayoshi Kosaka, Yoshiho Seo, Naoki Itokawa, Hajime Inoue, Kazushige Takagi, Katsuya Irie
  • Publication number: 20090201226
    Abstract: A driving method for a plasma display panel is disclosed in which sustain pulses are alternately applied to a pair of display electrodes of plural discharge cells provided in the plasma display panel to generate a sustain discharge, thereby causing an image to be displayed on the plasma display panel. The sustain pulses include a two-crests discharge voltage waveform having two maximum values in which discharges are generated twice in a half cycle. The driving method includes consecutively applying the two-crests discharge voltage waveforms to the pair of display electrodes; and making a time until the second one of the maximum values of the subsequently applied two-crests discharge voltage waveform is clamped longer than a time until the second one of the maximum values of the initially applied two-crests discharge voltage waveform is clamped.
    Type: Application
    Filed: November 12, 2008
    Publication date: August 13, 2009
    Inventors: Naoki Itokawa, Katsumi Ito, Masaki Kimura, Junichi Kumagai, Yasunobu Hashimoto, Tomokatsu Kishi
  • Patent number: 7573440
    Abstract: In a plasma display device comprising: plural first, second, and third electrodes disposed adjacently and extending in a first direction, the third electrodes being provided between the first and second electrodes for repeating discharges; a dielectric layer covering the electrodes; a first electrode driving circuit for driving the first electrodes; a second electrode driving circuit for driving the second electrodes; and a third electrode driving circuit for driving the third electrodes, grayscale display is performed by a sub-field method, and the third electrodes are set to have a potential approximately the same as that of the first or second electrode at the discharge in the repetitive discharges. In this plasma display device, the third electrode driving circuit makes the third electrode operate as an anode at least once at least in one sub-field from minimum luminance and makes it operate as a cathode in the rest thereof.
    Type: Grant
    Filed: January 9, 2006
    Date of Patent: August 11, 2009
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Takashi Sasaki, Takayuki Kobayashi, Naoki Itokawa
  • Patent number: 7570231
    Abstract: A method for driving a plasma display panel is provided in which wasteful power consumption is reduced and light emission efficiency is improved when the number of cells to be lighted is relatively small. The method includes classifying a display ratio into plural group ranges, selecting a suitable display pulse waveform for each group range, detecting the display ratio of an object to be displayed in a real display, and plural types of display pulses having different waveforms are used differently in accordance with the result of the detection. The display ratio means a ratio of the number of cells to be lighted to the number of cells of the screen.
    Type: Grant
    Filed: March 24, 2004
    Date of Patent: August 4, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Naoki Itokawa, Yoshiho Seo, Yasunobu Hashimoto, Tetsuya Sakamoto, Tomokatsu Kishi
  • Publication number: 20090160739
    Abstract: A technology for the four-electrode type PDP for preventing the lowering of luminance depending on the display load ratio due to the voltage drop at electrode by mitigating concentration of discharge timing. On a front substrate of a PDP (10), a first (X) electrode, a second (Y) electrode, and a third (Z) electrode therebetween are arranged in parallel in a first direction. Between Substrates, barrier ribs for sectioning cells 3 of respective colors of R, G, B and phosphor layers of respective colors are provided. In the respective cells (3), an interval of the X, Y electrodes is roughly constant. It is a structure where intervals between the X, Y electrodes and the Z electrode (XZ, YZ) are different. Particularly, an interval of R is narrow and an interval of B is wide.
    Type: Application
    Filed: August 26, 2005
    Publication date: June 25, 2009
    Inventors: Takayuki Kobayashi, Takashi Sasaki, Naoki Itokawa, Tooru Teraoka
  • Publication number: 20090153543
    Abstract: In a technique of a PDP having a four-electrode structure of (X, Y, Z, and A), the technique capable of preventing a delay of a discharge timing due to a voltage applied to the Z electrode is provided. In the four-electrode product structure of (X, Y, Z, and A) and a PDP in which rows are formed at both sides of a Y electrode, for a voltage waveform applied to each electrode (for example, X1, Zo, Y1, Ze, X2, Zo, and Y2) from the drive circuit side, a voltage (Vt) of the narrow width trigger pulse (65) of a positive polarity applied to the Z electrode is configured to be a voltage higher than the voltage (Vs) of the sustain pulses of X and Y (45, 46, 55, and 56).
    Type: Application
    Filed: February 1, 2006
    Publication date: June 18, 2009
    Applicant: FUJITSU HITACHI PLASAMA DISPLAY LIMITED
    Inventors: Takashi Sasaki, Tetsuya Sakamoto, Naoki Itokawa, Takayuki Kobayashi
  • Publication number: 20090135094
    Abstract: A plasma display device capable of realizing an interlace drive in one line display and an interlace drive in two lines display by switching thereof without deteriorating display quality, is provided. The interlace drive in one line display and the interlace drive in two lines display are realized such that: the interlace drive in one line display is performed by applying a sustain pulse for even display lines or odd display lines within a plasma display panel in each frame; and the interlace drive in two lines display is performed by applying the sustain pulse while setting the even display lines and the odd display lines adjacent above and below as one set and writing an identical data thereto. In addition, the all-cell reset is performed once per unit time at the interlace drive in two lines display, and an increase of background luminance is prevented by suppressing the increase in the number of times of the all-cell reset in the two lines display.
    Type: Application
    Filed: August 4, 2008
    Publication date: May 28, 2009
    Inventors: Masayuki Shibata, Katsumi Ito, Naoki Itokawa, Tomonari Misawa
  • Publication number: 20090096717
    Abstract: A technique which enables improvement of luminance and reduction of consumption power in a sustain discharge driving of a four-electrode structure PDP, particularly, by devising driving method to Z electrodes. In this plasma display device, a sustain discharge by a method to apply a narrow pulse to the Z electrode and a method to apply a fixed potential to the Z electrode are switched according to a judgment of range of display load ratio in driving sustain discharge from a controller and driver to the PDP and used.
    Type: Application
    Filed: July 26, 2005
    Publication date: April 16, 2009
    Inventors: Naoki Itokawa, Tetsuya Sakamoto, Takayuki Kobayashi, Tomokatsu Kishi, Yasunobu Hashimoto
  • Patent number: 7518573
    Abstract: In a plasma display device comprising: plural first, second, and third electrodes disposed adjacently and extending in a first direction, the third electrodes being provided between the first and second electrodes for repeating discharges; a dielectric layer covering the electrodes, a first electrode driving circuit for driving the first electrodes; a second electrode driving circuit for driving the second electrodes; and a third electrode driving circuit for driving the third electrodes, grayscale display is performed by a sub-field method, and the third electrodes are set to have a potential approximately the same as that of the first or second electrode at the discharge in the repetitive discharges. The third electrode driving circuit changes the ratio of the discharges in which the third electrodes operate as cathodes to the discharges in which they operate as anodes in the period when the discharges are repeated, at least in one sub-field.
    Type: Grant
    Filed: January 9, 2006
    Date of Patent: April 14, 2009
    Assignee: Fujitsu Hitachi Plasma Display Limited
    Inventors: Takashi Sasaki, Takayuki Kobayashi, Naoki Itokawa
  • Publication number: 20090066610
    Abstract: Provided is a plasma display apparatus capable of reducing power consumption by effectively using charges charged in a plasma display panel and achieving a high luminance by a reduction in reactive power. This plasma display apparatus includes: a plasma display panel in which X electrodes, Y electrodes, and Z electrodes are disposed on a front substrate and address electrodes are disposed on a rear substrate; and an X drive circuit, a Y drive circuit, a Z drive circuit and an address drive circuit for performing discharge light emission by applying a Z pulse between the Z electrode and the X electrode or between the Z electrode and the Y electrode and applying an X (Y) pulse between the X electrode and the Y electrode. The Z drive circuit includes a coil and switches using an LC resonance operation with the capacitance of the plasma display panel, and the Z pulse having a narrow pulse width can be generated by generating a Z pulse in the Z drive circuit.
    Type: Application
    Filed: August 23, 2005
    Publication date: March 12, 2009
    Inventors: Tetsuya Sakamoto, Naoki Itokawa, Takayuki Kobayashi, Tomokatsu Kishi