Patents by Inventor Mitsuharu Tai
Mitsuharu Tai 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: 7906834Abstract: A display device having a thin film semiconductor device including a semiconductor thin film having first and second semiconductor regions formed each into a predetermined shape above an insulative substrate, a conductor fabricated into a predetermined shape to the semiconductor thin film and a dielectric film put between the semiconductor thin film and the conductor, in which the semiconductor thin film is a polycrystal thin film with the crystallization ratio thereof exceeding 90% and the difference of unevenness on the surface of the semiconductor thin film does not exceed 10 nm.Type: GrantFiled: July 29, 2008Date of Patent: March 15, 2011Assignee: Hitachi Displays, Ltd.Inventors: Toshiyuki Mine, Mitsuharu Tai, Akio Shima
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Patent number: 7902003Abstract: An image display device capable of high-resolution and smooth moving image display, equipped with TFTs in an n-type (or p-type) semiconductor layer with a high on-off ratio and a low resistance. In polysilicon crystallization by laser annealing, an n-type (or p-type) semiconductor layer with a low resistance is produced by performing the following processes in order: implanting nitrogen (N) ions into an amorphous silicon precursor semiconductor film; laser crystallization; implanting n-type (or p-type) dopant ions; and annealing for dopant activation. When fabricating TFTs, this low-resistance semiconductor layer is used to form a source and a drain. Since C, N, and O impurities decrease the mobility of the TFTs, polysilicon is used in which the contaminants concentrations meet the following conditions: carbon concentration ?3×1019 cm?3, nitrogen concentration ?5×1017 cm?3, and oxygen concentration ?3×1019 cm?3.Type: GrantFiled: January 5, 2007Date of Patent: March 8, 2011Assignee: Hitachi Displays, Ltd.Inventors: Kiyoshi Ouchi, Mutsuko Hatano, Takeshi Sato, Mitsuharu Tai
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Patent number: 7838379Abstract: In a phase change memory, electric property of a diode used as a selection device is extremely important. However, since crystal grain boundaries are present in the film of a diode using polysilicon, it involves a problem that the off leak property varies greatly making it difficult to prevent erroneous reading. For overcoming the problem, the present invention provides a method of controlling the temperature profile of an amorphous silicon in the laser annealing for crystallizing and activating the amorphous silicon thereby controlling the crystal grain boundaries. According to the invention, variation in the electric property of the diode can be decreased and the yield of the phase-change memory can be improved.Type: GrantFiled: January 29, 2009Date of Patent: November 23, 2010Assignee: Hitachi, Ltd.Inventors: Masaharu Kinoshita, Motoyasu Terao, Hideyuki Matsuoka, Yoshitaka Sasago, Yoshinobu Kimura, Akio Shima, Mitsuharu Tai, Norikatsu Takaura
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Patent number: 7666769Abstract: There is provided a method for fabricating an image display device having an active matrix substrate including high-performance transistor circuits operating with high mobility as drive circuits for driving pixel portions which are arranged as a matrix. The portion of a polysilicon film formed in a drive circuit region DAR1 provided on the periphery of the pixel region PAR of the active matrix substrate SUB1 composing the image display device is irradiated and scanned with a pulse modulated laser beam or a pseudo CW laser beam to be reformed into a quasi-strip-like-crystal silicon film having a crystal boundary continuous in the scanning direction so that discrete reformed regions each composed of the quasi-strip-like-crystal silicon film are formed.Type: GrantFiled: February 6, 2007Date of Patent: February 23, 2010Assignee: Hitachi, Ltd.Inventors: Mutsuko Hatano, Shinya Yamaguchi, Takeo Shiba, Mitsuharu Tai, Hajime Akimoto
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Publication number: 20090189137Abstract: In a phase change memory, electric property of a diode used as a selection device is extremely important. However, since crystal grain boundaries are present in the film of a diode using polysilicon, it involves a problem that the off leak property varies greatly making it difficult to prevent erroneous reading. For overcoming the problem, the present invention provides a method of controlling the temperature profile of an amorphous silicon in the laser annealing for crystallizing and activating the amorphous silicon thereby controlling the crystal grain boundaries. According to the invention, variation in the electric property of the diode can be decreased and the yield of the phase-change memory can be improved.Type: ApplicationFiled: January 29, 2009Publication date: July 30, 2009Inventors: Masaharu Kinoshita, Motoyasu Terao, Hideyuki Matsuoka, Yoshitaka Sasago, Yoshinobu Kimura, Akio Shima, Mitsuharu Tai, Norikatsu Takaura
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Publication number: 20090140233Abstract: A nonvolatile semiconductor memory device having a large storage capacity and stabilized rewriting conditions in which a memory cell includes a nonvolatile recording material layer, a selector element and a semiconductor layer provided between the nonvolatile recording material layer and the selector element and having a thickness ranging from 5 to 200 nm.Type: ApplicationFiled: November 10, 2008Publication date: June 4, 2009Inventors: Masaharu KINOSHITA, Motoyasu Terao, Hideyuki Matsuoka, Yoshitaka Sasago, Yoshinobu Kimura, Akio Shima, Mitsuharu Tai, Norikatsu Takaura
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Publication number: 20090085042Abstract: A display device having a thin film semiconductor device including a semiconductor thin film having first and second semiconductor regions formed each into a predetermined shape above an insulative substrate, a conductor fabricated into a predetermined shape to the semiconductor thin film and a dielectric film put between the semiconductor thin film and the conductor, in which the semiconductor thin film is a polycrystal thin film with the crystallization ratio thereof exceeding 90% and the difference of unevenness on the surface of the semiconductor thin film does not exceed 10 nm.Type: ApplicationFiled: July 29, 2008Publication date: April 2, 2009Inventors: Toshiyuki Mine, Mitsuharu Tai, Akio Shima
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Publication number: 20090057676Abstract: A thin film semiconductor device is provided which includes an insulating substrate, a Si thin film formed over the insulating substrate, and a transistor with the Si thin film as a channel thereof. The Si thin film includes a polycrystal where a plurality of narrow, rectangular crystal grains are arranged. A surface of the polycrystal is flat at grain boundaries thereof. Also, an average film thickness of the boundaries of crystals of the Si thin film ranges from 90 to 100% of an intra-grain average film thickness.Type: ApplicationFiled: October 27, 2008Publication date: March 5, 2009Inventors: Shinya YAMAGUCHI, Mutsuko Hatano, Mitsuharu Tai, Sedng-Kee Park, Takeo Shiba
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Publication number: 20080303022Abstract: A highly sensitive optical sensor element, and a switch element such as a sensor driver circuit are formed on the same insulating substrate by using an LTPS planar process to provide a low cost area sensor (optical sensor device) incorporating the sensor driver circuit and the like or an image display device incorporating the optical sensor element. As an optical sensor element structure, one electrode of the sensor element is manufactured with the same film of the polycrystalline silicon film that is an active layer of the switch element constituting a circuit. A photoelectric conversion unit for performing photoelectric conversion is made of an amorphous silicon or a polycrystalline silicon film of an intrinsic layer. A structure in which the amorphous silicon of the photoelectric conversion unit and the insulating layer are sandwiched between two electrodes of the sensor element is adopted.Type: ApplicationFiled: February 25, 2008Publication date: December 11, 2008Inventors: Mitsuharu Tai, Masayoshi Kinoshita
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Publication number: 20080290344Abstract: An image display device manufactured by using a polycrystalline semiconductor film. The polycrystalline semiconductor film is composed of crystal grains with a region free from crystal grain boundaries of at least 2 ?m in width and at least 3 ?m in length, small crystal grain boundary groups each composed of three or more crystal grain boundaries arranged substantially in parallel to each other and with an interval of not greater than 100 ?m are included in a part of the region, and the small crystal grain boundary groups are partially eliminated.Type: ApplicationFiled: May 29, 2008Publication date: November 27, 2008Inventors: Mitsuharu TAI, Mutsuko HATANO, Takeshi SATO, Seongkee PARK, Kiyoshi OUCHI
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Patent number: 7456428Abstract: A semiconductor thin film is manufactured by scanning laser light or a substrate onto an arbitrary region of the semiconductor thin film and irradiating a laser thereon. The semiconductor thin film is formed by the substantially belt-shaped crystal being crystallized such that crystalline grains grow in the scanning direction, on the substrate, on XY coordinates where value x of beam size W (?m) of the laser light measured in substantially the same direction as the scanning direction is defined as X axis, and where value y of scanning velocity Vs (m/s) is defined as Y axis, the crystallization processing is performed within a region where all of the following conditions hold: condition 1: the beam size W is larger than wavelength of the laser beam, condition 2: the scanning velocity Vs is smaller than upper-limit of crystal growth speed, and condition 3: x×(1/y)<25 ?s.Type: GrantFiled: February 28, 2007Date of Patent: November 25, 2008Assignee: Hitachi Displays, Ltd.Inventors: Mutsuko Hatano, Mikio Hongo, Akio Yazaki, Mitsuharu Tai, Takeshi Noda, Yukio Takasaki
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Patent number: 7456913Abstract: A large number of pixels PXL are arranged in a matrix fashion in a display region DSP on an insulating substrate. Disposed around the display region DSP are a drain-side pixel-driving circuit including a drain shift register DSR, a digital-to-analog converter circuit DAC, a drain level shifter DLS, a buffer BF and sampling switches SSW; and a gate-side pixel-driving circuit including a gate shift register GSR and a gate level shifter GLS, and various kinds of circuits. Current mobility of thin film transistors constituting a circuit region SX requiring high-speed operation of these pixel-driving circuits is improved by optimizing a combination of plural layouts, arrangements and configurations for the respective circuits to meet the specifications special for the respective circuits.Type: GrantFiled: July 23, 2007Date of Patent: November 25, 2008Assignees: Hitachi, Ltd., Hitachi Displays, Ltd.Inventors: Mitsuharu Tai, Mutsuko Hatano, Shinya Yamaguchi, Takeo Shiba, Hideo Sato
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Patent number: 7442958Abstract: A thin film semiconductor device is provided which includes an insulating substrate, a Si thin film formed over the insulating substrate, and a transistor with the Si thin film as a channel thereof. The Si thin film includes a polycrystal where a plurality of narrow, rectangular crystal grains are arranged. A surface of the polycrystal is flat at grain boundaries thereof. Also, an average film thickness of the boundaries of crystals of the Si thin film ranges from 90 to 100% of an intra-grain average film thickness.Type: GrantFiled: June 26, 2007Date of Patent: October 28, 2008Assignee: Hitachi, Ltd.Inventors: Shinya Yamaguchi, Mutsuko Hatano, Mitsuharu Tai, Sedng-Kee Park, Takeo Shiba
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Publication number: 20080164481Abstract: An image display apparatus with an illuminance sensor, where the packaging cost, mechanical reliability due to packaging, and product yield are maintained. In the same semiconductor film as a thin-film-transistor (TFT) consisting of a pixel formed over an insulating substrate constituting a pixel, plural photo-sensors composed of a TFT for detecting light which has different detecting wavelength bands, and a signal processing circuit for generating a signal which controls the brightness of the pixel on the basis of the output of the photo-sensor are formed. The photo-sensor detects light energy of different wavelength bands by using a filter having a different film thickness of the semiconductor film or a different light transmission band. Ambient illuminance is detected by processing the output of each sensor in the signal processing circuit. The detected signal is fed back to the brightness control of the pixel.Type: ApplicationFiled: December 5, 2007Publication date: July 10, 2008Inventors: Mitsuharu Tai, Hiroshi Kageyama
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Publication number: 20080164473Abstract: The present invention provides an image display unit integrated with a photo-sensor, comprising a photo-sensing element with high sensitivity and low noise and a polycrystalline silicon TFT prepared at the same time on an insulating substrate using planer process. After a first electrode 11 and a second electrode 12 of the photo-sensing element are made of polycrystalline silicon film, a light receiving layer (photoelectric conversion layer) 13 of the photo-sensing element is prepared by amorphous silicon film on upper layer. In this case, a polycrystalline silicon TFT is prepared at the same time.Type: ApplicationFiled: December 12, 2007Publication date: July 10, 2008Inventors: Mitsuharu Tai, Toshio Miyazawa
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Publication number: 20080142920Abstract: According to the present invention, a highly sensitive photo-sensing element and a sensor driver circuit are prepared by planer process on an insulating substrate by using only polycrystalline material. Both the photo-sensing element and the sensor driver circuit are made of polycrystalline silicon film. As the photo-sensing element, a photo transistor is formed by using TFT, which comprises a first electrode 11 prepared on an insulating substrate 10, a photoelectric conversion region 14 and a second electrode 12, and a third electrode 13 disposed above the photoelectric conversion region 14. An impurity layer positioned closer to an intrinsic layer (density of active impurities is 1017 cm?3 or lower) is provided on the regions 15 and 16 on both sides under the third electrode 13 or on one of the regions 15 or 16 on one side.Type: ApplicationFiled: December 14, 2007Publication date: June 19, 2008Inventors: Mitsuharu Tai, Hideo Sato, Mutsuko Hatano, Masayoshi Kinoshita
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Patent number: 7384810Abstract: Only a region where TFTs constituting a high-performance circuit will be disposed in a precursor semiconductor film PCS on an insulating substrate GLS with an insulating layer UCL serving as an undercoat is irradiated with a first energy beam LSR so as to be poly-crystallized while growing crystal grains laterally. Further a second rapid thermal treatment is performed all over the panel so as to reduce defects in the crystal grains in a region PSI poly-crystallized by the aforementioned energy beam. Thus, a high-quality polycrystalline semiconductor thin film serving as TFTs for a high-performance circuit and having a high on-current, a low threshold value, a low variation and a sharp leading edge characteristic is obtained.Type: GrantFiled: May 26, 2006Date of Patent: June 10, 2008Assignee: Hitachi Displays, Ltd.Inventors: Mitsuharu Tai, Mutsuko Hatano, Takeshi Sato, Seongkee Park, Kiyoshi Ouchi
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Publication number: 20070262319Abstract: A large number of pixels PXL are arranged in a matrix fashion in a display region DSP on an insulating substrate. Disposed around the display region DSP are a drain-side pixel-driving circuit including a drain shift register DSR, a digital-to-analog converter circuit DAC, a drain level shifter DLS, a buffer BF and sampling switches SSW; and a gate-side pixel-driving circuit including a gate shift register GSR and a gate level shifter GLS, and various kinds of circuits. Current mobility of thin film transistors constituting a circuit region SX requiring high-speed operation of these pixel-driving circuits is improved by optimizing a combination of plural layouts, arrangements and configurations for the respective circuits to meet the specifications special for the respective circuits.Type: ApplicationFiled: July 23, 2007Publication date: November 15, 2007Inventors: Mitsuharu Tai, Mutsuko Hatano, Shinya Yamaguchi, Takeo Shiba, Hideo Sato
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Publication number: 20070246709Abstract: A thin film semiconductor device is provided which includes an insulating substrate, a Si thin film formed over the insulating substrate, and a transistor with the Si thin film as a channel thereof. The Si thin film includes a polycrystal where a plurality of narrow, rectangular crystal grains are arranged. A surface of the polycrystal is flat at grain boundaries thereof. Also, an average film thickness of the boundaries of crystals of the Si thin film ranges from 90 to 100% of an intra-grain average film thickness.Type: ApplicationFiled: June 26, 2007Publication date: October 25, 2007Inventors: Shinya YAMAGUCHI, Mutsuko Hatano, Mitsuharu Tai, Sedng-Kee Park, Takeo Shiba
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Patent number: 7262821Abstract: A large number of pixels PXL are arranged in a matrix fashion in a display region DSP on an insulating substrate. Disposed around the display region DSP are a drain-side pixel-driving circuit including a drain shift register DSR, a digital-to-analog converter circuit DAC, a drain level shifter DLS, a buffer BF and sampling switches SSW; and a gate-side pixel-driving circuit including a gate shift register GSR and a gate level shifter GLS, and various kinds of circuits. Current mobility of thin film transistors constituting a circuit region SX requiring high-speed operation of these pixel-driving circuits is improved by optimizing a combination of plural layouts, arrangements and configurations for the respective circuits to meet the specifications special for the respective circuits.Type: GrantFiled: February 6, 2004Date of Patent: August 28, 2007Assignee: Hitachi Displays, Ltd.Inventors: Mitsuharu Tai, Mutsuko Hatano, Shinya Yamaguchi, Takeo Shiba, Hideo Sato