Patents by Inventor Hitoshi Hirakawa
Hitoshi Hirakawa 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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Patent number: 7479736Abstract: A display device capable of realizing a desired color temperature is provided. Phosphor layers 5a, 5b and 5c, which are excited by ultraviolet radiation produced by discharge and emit red, green and blue visible light, are formed inside a red, green and blue gas discharge tube 1a, 1b, and 1c, respectively. The height Yc of the phosphor layer 5c with respect to a rear support body 20 is higher than the heights Ya and Yb of the phosphor layers 5a and 5b with respect to the rear support member 20, and establishes the relationship Yc>Ya=Yb. Therefore, the distance from the phosphor layer 5c to the opposite discharge surface on a front support body is shorter than those from the phosphor layers 5a and 5b, the visible light emitted from the display device 10 is shifted toward blue, that is, the color temperature increases.Type: GrantFiled: February 9, 2005Date of Patent: January 20, 2009Assignee: Shinoda Plasma CorporationInventors: Koji Shinohe, Manabu Ishimoto, Kenji Awamoto, Hitoshi Yamada, Akira Tokai, Yosuke Yamazaki, Hitoshi Hirakawa
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Publication number: 20080297447Abstract: A display device (10) includes: a scan drive circuit (74) operating to apply scan voltages to respective ones of the display electrodes (2, Y1-Yn) during a first period of time, and apply sustain voltage pulses to the ones of the display electrodes (2, Y1-Yn) during a second period of time; a sustain voltage circuit (64) applying a potential for a sustain voltage pulse between two inputs of said scan drive circuit through two respective signal lines (SU, SD) during said second period of time; a switch (SW1) short-circuiting the two input terminals of said scan drive circuit during said second period of time; and a switch control circuit (604) causing said short-circuiting switch to operate. The switch control circuit provides a control signal (SW_CTRL) to operate said short-circuiting switch so as to short-circuit the two input terminals during said second period of time.Type: ApplicationFiled: August 7, 2008Publication date: December 4, 2008Applicant: SHINODA PLASMA CORPORATIONInventors: Kenji Awamoto, Manabu Ishimoto, Hitoshi Hirakawa, Koji Shinohe
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Publication number: 20080258603Abstract: A color display device (10) includes: a plurality of gas discharge tubes disposed side by side, the gas discharge tubes having phosphor layers (4R, 4G, 4B) of different materials for respective colors disposed therein and containing discharge gas therein, the gas discharge tubes each having a plurality of light-emitting points disposed along the length thereof; a plurality of display electrodes disposed on display-side surfaces of the gas discharge tubes; and a plurality of signal electrodes (3) disposed on the rear sides of the respective gas discharge tubes. The discharge gas in each of the plurality of gas discharge tubes comprises a mixture of a plurality of different gases. The gas discharge tubes including respective different materials for the phosphor layers have respective different compositions of the plurality of different gases. Each composition of the plurality of different gases has such respective partial pressure ratios as to raise a color temperature.Type: ApplicationFiled: June 20, 2008Publication date: October 23, 2008Applicant: SHINODA PLASMA CO., LTD.Inventors: Koji Shinohe, Manabu Ishimoto, Kenji Awamoto, Hitoshi Hirakawa, Yosuke Yamazaki
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Patent number: 7436375Abstract: An address pulse width is reduced, so that a display period for driving a plasma display panel (PDP) can be made longer. The PDP comprises cells, each cell having parallel first and second electrodes covered with dielectric and a third electrode disposed in a direction crossing the first and second electrodes. A method of driving the PDP comprises addressing ones of the cells to be illuminated for displaying. The addressing comprises effecting an operation of producing wall charges having the same polarity on the dielectric layers over the first and second electrodes before an operation of producing discharge between the second and third electrodes for addressing, so that the discharge for addressing occurs only between the second and third electrodes.Type: GrantFiled: November 30, 2004Date of Patent: October 14, 2008Assignee: Hitachi, Ltd.Inventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto
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Publication number: 20080225028Abstract: A light emitting tube array drivable in an ADS subfield mode wherein a fluorescent material layer is arranged on an inner wall of each light emitting tube sandwiched between a front substrate and a rear substrate, a discharge gas is airtightly put therein, and a plurality of electrodes formed for generating discharge in the light emitting tube are formed on the front substrate and the rear substrate has a problem that a discharge error is caused so that its cells wherein light emission should be caused do not emit light since the volume of its discharge spaces is extremely larger than that in plasma display panels or since the discharge spaces are partitioned by the light emitting tubes.Type: ApplicationFiled: September 1, 2005Publication date: September 18, 2008Inventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto
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Patent number: 7423614Abstract: An address pulse width is reduced so that a display period for driving a plasma display panel (PDP) can be made longer. The PDP comprises cells, each cell having first and second electrodes covered with dielectric and a third electrode covered with dielectric disposed in a direction crossing the first and second electrodes. A method of driving the PDP comprises addressing ones of the cells to be illuminated for displaying, by applying, between the second and third electrodes of the respective cells to be illuminated, a preparatory address pulse having a pulse width that produces no discharge, and by subsequently applying therebetween main address pulses, each main address pulse having a pulse width that produces discharge.Type: GrantFiled: November 30, 2004Date of Patent: September 9, 2008Assignee: Hitachi Plasma Patent Licensing Co., Ltd.Inventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto
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Publication number: 20080199815Abstract: A plasma display panel in which projections are formed in grooves between partitions and phosphor layers are provided on the projections so as to increase the area where phosphor adheres and thereby to increase the luminance. A couple of substrates are opposed to each other to form a discharge space. Band-like partitions partitioning the discharge space are arranged on the back or front substrate. Wall-like projections lower than the partitions and high enough to increase the area where phosphor layers are formed are provided in the region where the discharge space is formed in the long grooves between the partitions or around the discharge space. Phosphor layers are formed in the grooves between the partitions including the wall-like projections. A method for producing such a plasma display panel is also disclosed.Type: ApplicationFiled: September 28, 2007Publication date: August 21, 2008Applicant: HITACHI, LTD.Inventors: Osamu Toyoda, Akira Tokai, Kazunori Inoue, Fumihiro Namiki, Saburou Morita, Yojiro Shimada, Hitoshi Hirakawa, Takashi Katayama
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Patent number: 7371508Abstract: A plasma display panel in which projections are formed in grooves between partitions and phosphor layers are provided on the projections so as to increase the area where phosphor adheres and thereby to increase the luminance. A couple of substrates are opposed to each other to form a discharge space. Band-like partitions partitioning the discharge space are arranged on the back or front substrate. Wall-like projections lower than the partitions and high enough to increase the area where phosphor layers are formed are provided in the region where the discharge space is formed in the long grooves between the partitions or around the discharge space. Phosphor layers are formed in the grooves between the partitions including the wall-like projections. A method for producing such a plasma display panel is also disclosed.Type: GrantFiled: March 29, 2004Date of Patent: May 13, 2008Assignee: Hitachi, Ltd.Inventors: Osamu Toyoda, Akira Tokai, Kazunori Inoue, Fumihiro Namiki, Saburou Morita, Yojiro Shimada, Hitoshi Hirakawa, Takashi Katayama
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Publication number: 20080079346Abstract: In accordance with an aspect of the present invention, a color display device (10) includes a plurality of gas discharge tubes disposed side by side. The gas discharge tubes have respective phosphor layers (4R, 4G, 4B) of different materials for different colors disposed therein and containing discharge gas therein. Each of the gas discharge tubes has a plurality of light-emitting points disposed along the length thereof. The color display device further includes a plurality of display electrodes disposed on the display screen side of the gas discharge tubes, and a plurality of signal electrodes (3) disposed on the rear side of the gas discharge tubes. Voltage control layers (6R, 6G, 6B) are disposed between the phosphor layers and the signal electrodes. The voltage control layers are made of materials which change firing voltages applied between the display electrodes and the signal electrodes.Type: ApplicationFiled: September 21, 2007Publication date: April 3, 2008Applicant: SHINODA PLASMA CORPORATIONInventors: Manabu Ishimoto, Hitoshi Hirakawa, Kenji Awamoto, Hitoshi Yamada, Akira Tokai
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Publication number: 20080067936Abstract: A color display device (10) includes: a plurality of gas discharge tubes disposed side by side, the gas discharge tubes having phosphor layers (4R, 4G, 4B) of different materials for respective colors disposed therein and containing discharge gas therein, the gas discharge tubes each having a plurality of light-emitting points disposed along the length thereof; a plurality of display electrodes disposed on display-side surfaces of the gas discharge tubes; and a plurality of signal electrodes (3) disposed on the rear sides of the respective gas discharge tubes. Those ones of the gas discharge tubes which include a same, particular material in the phosphor layers (4R, 4G, 4B) thereof have voltage adjusting layers (6R, 6B) disposed between rear surfaces and the signal electrodes thereof. The voltage adjusting layers are made of a material which adjusts a firing voltage for discharge between the display electrodes and the signal electrodes.Type: ApplicationFiled: November 19, 2007Publication date: March 20, 2008Applicant: SHINODA PLASMA CO., LTD.Inventors: Manabu Ishimoto, Hitoshi Hirakawa, Yosuke Yamazaki, Koji Shinohe, Kenji Awamoto
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Publication number: 20080061691Abstract: A display device (10) includes a plurality of gas discharge tubes (11R, 11G, 11B, . . . ) sandwiched between a front support plate (31) and a plurality of rear support plates (321, 322, . . . 328). The display device further includes: a plurality of display electrodes (2) formed on a surface of the front support plate facing the plurality of gas discharge tubes to extend across tube axes of the plurality of gas discharge tubes; a plurality of signal electrodes (3) formed on surfaces of the plurality of rear support plates facing the plurality of gas discharge tubes to extend along the longitudinal direction of the plurality of gas discharge tubes. Another rear support plate (330) for supporting the plurality of rear support plates is disposed on surfaces of the plurality of rear support plates opposite to the surfaces facing the plurality of gas discharge tubes.Type: ApplicationFiled: November 9, 2007Publication date: March 13, 2008Applicant: SHINODA PLASMA CO., LTD.Inventors: Akira Tokai, Manabu Ishimoto, Hitoshi Hirakawa, Yosuke Yamazaki, Koji Shinohe, Kenji Awamoto
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Publication number: 20080048546Abstract: A display device (12) has a display screen, the display screen comprising a plurality of gas discharge tubes (20R, 20G, 20B, . . . 28R, 28G, 28B) disposed side by side. Each of the gas discharge tubes includes a phosphor layer (4) formed therein and also includes a discharge gas contained therein. Each gas discharge tube has a plurality of light-emitting points. Each of the plurality of gas discharge tubes (20R, 20G, 20B, . . . 28R, 28G, 28B) is curved along the longitudinal direction thereof. The display screen is formed by combining the plurality of gas discharge tubes having different magnitudes of curvature.Type: ApplicationFiled: August 24, 2007Publication date: February 28, 2008Applicant: SHINODA PLASMA CO.,LTDInventors: Manabu Ishimoto, Yosuke Yamazaki, Hitoshi Yamada, Hitoshi Hirakawa, Akira Tokai, Koji Shinohe, Kenji Awamoto
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Patent number: 7336027Abstract: A plasma tube array according to the present invention includes plural light emitting tubes that have fluorescent material layers inside and are mutually lined up in parallel. The plasma tube array includes pairs of display electrodes that are formed along the respective fluorescent material layers. The fluorescent material layers are disposed in sequence in the longitudinal direction of the light emitting tubes.Type: GrantFiled: June 20, 2005Date of Patent: February 26, 2008Assignee: Shinoda Plasma CorporationInventors: Yosuke Yamazaki, Manabu Ishimoto, Hitoshi Yamada, Hitoshi Hirakawa, Akira Tokai, Koji Shinohe, Kenji Awamoto
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Publication number: 20080024049Abstract: A plasma tube array includes a front supporting substrate, a back supporting substrate, display electrode pairs and signal electrodes, and wirings. The front supporting substrate and the back supporting substrate overlap each other, with a discharge space formed therebetween. The display electrode pairs are formed on the inner surface of the front supporting substrate. The signal electrodes are formed on the back substrate. The plasma tube array displays an image by allowing light to be emitted by applying a voltage to the signal electrodes and the display electrode pairs. The wirings are formed on an outer surface of the front supporting substrate so as to correspond respectively to the display electrodes. The wirings extend parallel to the display electrodes, and are connected to the corresponding display electrodes, respectively.Type: ApplicationFiled: September 27, 2007Publication date: January 31, 2008Applicant: SHINODA PLASMA CORPORATIONInventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto
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Publication number: 20080007176Abstract: A display device (10) including a plurality of gas discharge tubes (11R, 11G, 11B) sandwiched between a front support plate (31) and a rear support plate (32). The display device further including: a plurality of display electrodes (2) formed on a surface of the front support plate facing the gas discharge tubes to extend across the axial direction of the gas discharge tubes; and a plurality of signal electrodes (3) formed on a surface of the rear support plate facing the gas discharge tubes to extend along the longitudinal direction of the gas discharge tubes. The plurality of signal electrodes are divided into a plurality of groups (B1, B2, . . . , Ba). Each group includes a predetermined number of signal electrodes. The distance between adjacent ones of the signal electrodes in each group has a first distance. The distance between adjacent ones of said signal electrodes in each group is substantially equal to a first distance (PT).Type: ApplicationFiled: September 17, 2007Publication date: January 10, 2008Applicant: SHINODA PLASMA CO., LTDInventors: Manabu Ishimoto, Hitoshi Hirakawa, Kenji Awamoto
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Patent number: 7315121Abstract: An arc tube array-type display device includes an arc tube array, a supporting member, a plurality of display electrodes, a plurality of scan electrodes, and a plurality of address electrodes. The arc tube array has a plurality of arc tubes arranged side by side. Each of the arc tubes has a discharging gas sealed therein. The supporting member supports the arc tube array. The plurality of display electrodes are arranged at an adjacent portion between the arc tubes, and generate an opposing discharge inside the arc tube by applying voltages to each of the arc tubes from both of the side faces. The plurality of scan electrodes are arranged on the display surface side of the arc tube in a stripe form in a direction intersecting the longitudinal direction of the arc tube so as to form light-emitting areas at intersecting portions against the arc tubes. The plurality of address electrodes are used for selecting light-emitting areas arranged on the back surface side of the respective arc tubes.Type: GrantFiled: March 23, 2006Date of Patent: January 1, 2008Assignee: Shinoda Plasma CorporationInventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto
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Patent number: 7298086Abstract: The present invention provides a plasma tube array including: plural light-emitting tubes; a front supporting member and a back supporting member which spread over the front and back of the light-emitting tubes; plural display electrode pairs provided on the surface of the front supporting member facing the light-emitting tubes; and plural signal electrodes provided on the surface of the back supporting member facing the light-emitting tubes. Each display electrode constituting the display electrode pair is a display electrode which is made of a metal thin wire, provided with plural openings formed in a distributed manner and includes a first metal thin wire facing a discharge slit and extending along the discharge slit, and the first metal thin wire is a metal thin wire thicker than a second metal thin wire which forms a region closer to a non-discharge slit side than the first metal thin wire.Type: GrantFiled: September 1, 2005Date of Patent: November 20, 2007Assignee: Shinoda Plasma CorporationInventors: Koji Shinohe, Manabu Ishimoto, Kenji Awamoto, Hitoshi Yamada, Akira Tokai, Yosuke Yamazaki, Hitoshi Hirakawa
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Patent number: 7282858Abstract: A gas-discharge tube has a glass tube as its main body and a trench is provided in the axial direction of the glass tube on one surface (the surface opposed to the discharge surface) among the external surfaces of the glass tube. An address electrode is placed in the trench. The inner surface of the region of the glass tube where sustain electrodes are placed is formed to have a microscopic unevenness. A secondary electron emission film is formed on this inner surface where the unevenness is formed. In addition, a phosphor support member, whose cross section across the axis is in approximately a C-shape and where a phosphor layer has been formed in advance on the inner surface, is placed inside of the glass tube. Stable discharge characteristics is obtained by eliminating dispersion of the position of an electrode, relative to the gas-discharge tube.Type: GrantFiled: February 26, 2004Date of Patent: October 16, 2007Assignee: Shinoda Plasma CorporationInventors: Akira Tokai, Hitoshi Yamada, Manabu Ishimoto, Kenji Awamoto, Yosuke Yamazaki, Hitoshi Hirakawa, Akira Nakazawa, Koji Shinohe
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Patent number: 7256538Abstract: In an AC-driven gas discharge display device and especially a plasma tube array type, a return path is provided for alternate discharge current flowing between X and Y driver circuits. The AC-driven gas discharge display device comprises a front-side, transparent substrate and a rear-side substrate sandwiching therebetween a plurality of thin discharge tubes arranged side by side; a plurality of pairs of display electrodes on an inner surface of the front-side substrate; and a plurality of address electrodes, in a direction transverse to the plurality of display electrodes, the rear-side substrate on an inner surface. Striped light-blocking, electrically conductive films are disposed on an outer surface of the front-side substrate at locations between respective ones of the pairs of display electrodes and coupled at their opposite ends to respective points of a common reference potential in the X- and Y-electrode driver circuits, respectively, to provide a return path for alternate discharge current.Type: GrantFiled: August 17, 2005Date of Patent: August 14, 2007Assignee: Shinoda Plasma CorporationInventors: Manabu Ishimoto, Hitoshi Hirakawa, Kenji Awamoto, Akira Tokai, Koji Shinohe
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Publication number: 20070052621Abstract: In order to realize a display having good contrast and stable addressing by using a gas discharge display device having a screen of a three-electrode surface discharge structure having a characteristics that a counter discharge start voltage is higher than a surface discharge start voltage, prior to starting of initialization of an electrified state as canceling of setting of addressing that was performed last, positive charge is formed between opposed electrodes so that a discharge can be generated easily in the addressing after the initialization, and the initialization is performed so that the formed positive charge does not vanish.Type: ApplicationFiled: November 7, 2006Publication date: March 8, 2007Applicant: FUJITSU LIMITEDInventors: Hitoshi Hirakawa, Manabu Ishimoto, Kenji Awamoto