Patents by Inventor Koji Hiraga
Koji Hiraga 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: 7619693Abstract: The present invention provides a liquid crystal display device which can obtain a high image quality display by suppressing the fluctuation of a pixel voltage. Along a large number of drain lines which are driven in a time-division manner, a portion of gate line is extended and an additional capacitance is formed by an extending portion of the gate line which has fixed potential and the drain line.Type: GrantFiled: December 6, 2004Date of Patent: November 17, 2009Assignee: Hitachi Displays, Ltd.Inventors: Takahiro Fujioka, Koji Hiraga, Takehiko Kubota
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Patent number: 7440042Abstract: A display device includes a glass substrate having a gate line, a drain line, a pixel electrode, and a thin film transistor. A silicon nitride film is formed on the glass substrate, and a silicon oxide film is formed on the silicon nitride film. The thin film transistor is formed on the silicon oxide film, and includes a poly-silicon film, a gate electrode which is electrically connected to the gate line, a drain electrode which connected to the drain line, and a source electrode which is electrically connected to the pixel electrode. A gate insulation film is formed between the silicon oxide film and the gate electrode, and an interlayer film is interposed between the gate insulation film and the pixel electrode. The silicon nitride film has a larger film thickness than that of the silicon oxide film, and the films are configured so as to reduce reflection.Type: GrantFiled: July 11, 2007Date of Patent: October 21, 2008Assignee: Hitachi Displays, Ltd.Inventors: Tetsuya Nagata, Koji Hiraga, Masao Uehara, Koichi Fukuda
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Publication number: 20070258020Abstract: A display device includes a glass substrate having a gate line, a drain line, a pixel electrode, and a thin film transistor. A silicon nitride film is formed on the glass substrate, and a silicon oxide film is formed on the silicon nitride film. The thin film transistor is formed on the silicon oxide film, and includes a poly-silicon film, a gate electrode which is electrically connected to the gate line, a drain electrode which connected to the drain line, and a source electrode which is electrically connected to the pixel electrode. A gate insulation film is formed between the silicon oxide film and the gate electrode, and an interlayer film is interposed between the gate insulation film and the pixel electrode. The silicon nitride film has a larger film thickness than that of the silicon oxide film, and the films are configured so as to reduce reflection.Type: ApplicationFiled: July 11, 2007Publication date: November 8, 2007Inventors: Tetsuya Nagata, Koji Hiraga, Masao Uehara, Koichi Fukuda
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Patent number: 7245338Abstract: In a liquid crystal display device the reflection of light from a transmissive region is reduced, the contrast of images is enhanced and a display of inverted images is suppressed. The liquid crystal display device includes a first background film made of silicon nitride and a second background film made of silicon oxide over a glass substrate, and thin film transistors and light transmissive pixel portions are formed over the second background film. Each thin film transistor is constituted of a polysilicon film, a gate electrode, a drain electrode and a source electrode, while a gate insulation film, an interlayer insulation film and an organic film are formed over the pixel portion. Further, in the liquid crystal display device external light is reflected, wherein by forming the first background film thicker than the second background film, the inversion of images of a transmissive type liquid crystal panel can be suppressed.Type: GrantFiled: July 30, 2003Date of Patent: July 17, 2007Assignee: Hitachi Displays, Ltd.Inventors: Tetsuya Nagata, Koji Hiraga, Masao Uehara, Koichi Fukuda
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Patent number: 7027115Abstract: A liquid crystal display device includes a first transparent substrate having a plurality of electrodes, a second transparent substrate, a liquid crystal interposed between the first transparent substrate and the second transparent substrate, an illumination light source disposed on a back side of the first transparent substrate, pixel regions arranged in a matrix, and a reflecting film formed between the first transparent substrate and the electrodes. The reflecting film has at least one light transmission aperture in each pixel region and without slits at positions corresponding to gaps between adjacent ones of the pixel regions.Type: GrantFiled: February 18, 2004Date of Patent: April 11, 2006Assignees: Hitachi, Ltd., Hitachi Device Engineering Co., Ltd.Inventors: Souta Nemoto, Kazutoshi Yoshida, Masao Uehara, Noboru Hoshino, Yoshiaki Nakamura, Masayoshi Fujieda, Koji Hiraga
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Publication number: 20050140891Abstract: The present invention provides a liquid crystal display device which can obtain a high image quality display by suppressing the fluctuation of a pixel voltage. Along a large number of drain lines which are driven in a time-division manner, a portion of gate line is extended and an additional capacitance is formed by an extending portion of the gate line which has fixed potential and the drain line.Type: ApplicationFiled: December 6, 2004Publication date: June 30, 2005Inventors: Takahiro Fujioka, Koji Hiraga, Takehiko Kubota
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Publication number: 20050007522Abstract: The color characteristics of a semi-transmissive type liquid crystal display device are enhanced in a liquid crystal display device which includes a first substrate on which a plurality of pixel electrodes are formed, a second substrate which faces the first substrate in an opposed manner, color filters which are formed between the first substrate and the second substrate, reflection members which reflect light incident from the second substrate side, and a backlight which is provided at the outside of the first substrate In the color filters which correspond to first pixel electrodes opening portions are formed from sides close to a first side of the first substrate, and in the color filters which correspond to second pixel electrodes, opening portions are formed from sides close to the second side of the first substrate which faces the first side in an opposed manner.Type: ApplicationFiled: July 9, 2004Publication date: January 13, 2005Inventors: Koji Hiraga, Tetsuya Nagata, Takehiko Kubota, Takahiro Fujioka
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Publication number: 20040160555Abstract: A liquid crystal display device includes a first transparent substrate having a plurality of electrodes, a second transparent substrate, a liquid crystal interposed between the first transparent substrate and the second transparent substrate, an illumination light source disposed on a back side of the first transparent substrate, pixel regions arranged in a matrix, and a reflecting film formed between the first transparent substrate and the electrodes. The reflecting film has at least one light transmission aperture in each pixel region and without slits at positions corresponding to gaps between adjacent ones of the pixel regions.Type: ApplicationFiled: February 18, 2004Publication date: August 19, 2004Inventors: Souta Nemoto, Kazutoshi Yoshida, Masao Uehara, Noboru Hoshino, Yoshiaki Nakamura, Masayoshi Fujieda, Koji Hiraga
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Patent number: 6697137Abstract: A liquid crystal is interposed between a first transparent substrate having first electrodes and a second transparent substrate having other electrodes. Pixel regions are formed at portions where the first electrodes and the other electrodes are opposed to each other. A semitransparent reflecting film is formed between the first transparent substrate and the first electrodes. The semitransparent reflecting film is formed with light transmission apertures in each pixel region. The semitransparent reflecting film also occupies portions corresponding to the gaps between the adjacent pixel regions. Alternatively, in addition to the light transmission apertures, the semitransparent reflecting film is formed with slits at positions corresponding to the gaps between the adjacent pixel regions. A light absorption film is formed between the first transparent substrate and the semitransparent reflecting film at positions corresponding to the slits, or the slits are charged with a light absorption film.Type: GrantFiled: April 9, 2001Date of Patent: February 24, 2004Assignees: Hitachi, Ltd., Hitachi Device Engineering Co., Ltd.Inventors: Souta Nemoto, Kazutoshi Yoshida, Masao Uehara, Noboru Hoshino, Yoshiaki Nakamura, Masayoshi Fujieda, Koji Hiraga
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Publication number: 20040021805Abstract: The present invention provides a liquid crystal display device which reduces the reflection of light from a transmissive region, enhances a contrast of images and suppresses display of inverted images. The liquid crystal display device includes a first background film made of silicon nitride and a second background film made of silicon oxide over a glass substrate, and thin film transistors and light transmissive pixel portions are formed over the second background film. The thin film transistor is constituted of a polysilicon film, agate electrode, a drain electrode and a source electrode, while a gate insulation film, an interlayer insulation film and an organic film are formed over the pixel portion. Further, the liquid crystal display device has a function of reflecting an external light, wherein by forming the first background film thicker than the second background film, the inversion of images of a transmissive type liquid crystal panel can be suppressed.Type: ApplicationFiled: July 30, 2003Publication date: February 5, 2004Inventors: Tetsuya Nagata, Koji Hiraga, Masao Uehara, Koichi Fukuda
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Publication number: 20010040658Abstract: A liquid crystal is interposed between a first transparent substrate having one electrodes and a second transparent substrate having the other electrodes. Pixel regions are formed at portions where the one electrodes and the other electrodes are opposed to each other. A semitransparent reflecting film is formed between the first transparent substrate and the one electrodes. The semitransparent reflecting film is formed with light transmission apertures in each pixel region. The semitransparent reflecting film also occupies portions corresponding to the gaps between the adjacent pixel regions. Alternatively, in addition to the light transmission apertures, the semitransparent reflecting film is formed with slits at positions corresponding to the gaps between the adjacent pixel regions. A light absorption film is formed between the first transparent substrate and the semitransparent reflecting film at positions corresponding to the slits, or the slits are charged with a light absorption film.Type: ApplicationFiled: April 9, 2001Publication date: November 15, 2001Inventors: Souta Nemoto, Kazutoshi Yoshida, Masao Uehara, Noboru Hoshino, Yoshiaki Nakamura, Masayoshi Fujieda, Koji Hiraga