Patents by Inventor Akihisa Iwamoto

Akihisa Iwamoto 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).

  • Publication number: 20150269900
    Abstract: A gate driver (24) which is provided by an IGZO-GDM and a level shifter circuit (13) are connected to each other via a first through a fifth wires (OL1 through OL5). Each wire (OL) is connected to a discharge unit (190). If an electric power supply to a first through a fifth output circuits (OC1 through OC5) in the level shifter circuit (13) becomes lower than a lower operation limit value during a power-off sequence which is supposed to remove a residual charge from inside a panel, outputs from the first through the fifth output circuits (OC1 through OC5) assume a high-impedance state, whereupon a potential on each wire (OL) is drawn by a discharge unit (190) into a ground potential. Therefore, residual charge inside the panel is removed quickly and stably when power supply is shut off.
    Type: Application
    Filed: October 11, 2013
    Publication date: September 24, 2015
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Akihisa Iwamoto, Masami Ozaki, Tomohiko Nishimura, Kohji Saitoh, Masaki Uehata, Jun Nakata
  • Publication number: 20150042636
    Abstract: The present invention is intended to make it unlikely that, in a case where a transistor is turned on in preparation for an operation to turn off a power source of a liquid crystal display device, a DC voltage becomes applied across a pixel even if potential variation (kickback) occurs at a pixel electrode in reaction to a change in status of the transistor from an on state to an off state.
    Type: Application
    Filed: January 28, 2013
    Publication date: February 12, 2015
    Inventors: Kohji Saitoh, Akihisa Iwamoto, Jun Nakata, Masaki Uehata, Tomohiko Nishimura, Masami Ozaki
  • Patent number: 8952880
    Abstract: A display panel drive circuit includes a shift register constructed of unit circuits connected in stages. The unit circuits generate signal line selection signals, respectively, which signal line selection signals are made active for a respective certain period of time to form a respective pulse, and the pulses are outputted successively from respective unit circuits in order of ordinal number starting from a first stage until an end stage. In at least one embodiment, each of the unit circuits receive (i) clock signals generated based on a sync signal received from outside of the display panel drive circuit, (ii) a start pulse signal generated based on the sync signal, or a signal line selection signal generated in a stage different from its own stage, and (iii) a clear signal. The clear signal is made active in a case where anomalousness is included in the sync signal, and no pulse is outputted from the shift register until a subsequent vertical scanning period starts.
    Type: Grant
    Filed: December 17, 2008
    Date of Patent: February 10, 2015
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Takayuki Mizunaga, Hideki Morii, Akihisa Iwamoto, Masahiro Hirokane, Yuuki Ohta
  • Publication number: 20150030116
    Abstract: A shift register is configured so that each of first and second intermediate stages includes (i) a first input terminal supplied with a clock signal, (ii) a second input terminal supplied with a clock signal different in phase from the clock signal supplied to the first input terminal, (iii) an output terminal connected to the first input terminal via an output transistor, and (iv) a setting circuit, which is connected to the second input terminal and the output transistor, for setting an electric potential of a control terminal of the output transistor, the second intermediate stage includes a control circuit which is (i) connected to the setting circuit of the second intermediate stage and (ii) supplied with a control signal, an operation period (i) starts at a time when a shift start signal supplied to an initial stage is activated and (ii) ends at a time when an output of a final stage changes from activation to inactivation, and when the clock signal supplied to the first input terminal of the second int
    Type: Application
    Filed: March 5, 2013
    Publication date: January 29, 2015
    Inventors: Satoshi Horiuchi, Shinya Tanaka, Akira Tagawa, Yasuaki Iwase, Takayuki Mizunaga, Akihisa Iwamoto
  • Publication number: 20150009195
    Abstract: A liquid crystal display device includes: a data signal line; a scan signal line; a pixel electrode; a transistor connected to (i) the data signal line, (ii) the scan signal line, and (iii) the pixel electrode; and a common electrode, the liquid crystal display device being configured to turn on the transistor during a power-off sequence by causing a change in an electric potential of the scan signal line, the electric potential of the scan signal line reaching a first electric potential at a first timing after the change is initiated, and the common electrode being in an electrically floating state at a second timing which comes after the first timing.
    Type: Application
    Filed: January 25, 2013
    Publication date: January 8, 2015
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Kohji Saitoh, Akihisa Iwamoto, Masami Ozaki, Masaki Uehata, Jun Nakata, Tomohiko Nishimura
  • Patent number: 8922473
    Abstract: Provided is a display device capable of correctly displaying an image when surplus outputs are produced within a driver, regardless of a shifting direction of a shift register within the driver, without bringing about increase in cost and increase in consumption current. A timing controller (200) is provided with a register (22) that can store data indicating the length of a horizontal back porch when a shifting direction of a shift register within a source driver (300) is in a forward direction and data indicating the length of the horizontal back porch when the shifting direction is in an inverse direction. A source-start-pulse generation unit (21) within the timing controller (200) refers to the data within the register (22) according to the shifting direction of the shift register, and generates one of a first source start pulse signal (SSP1) for the forward direction and a second source start pulse signal (SSP2) for the inverse direction.
    Type: Grant
    Filed: October 17, 2011
    Date of Patent: December 30, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventor: Akihisa Iwamoto
  • Publication number: 20140306948
    Abstract: Provided are: a liquid crystal display device capable of rapidly removing residual electric charges in a panel when a power supply is turned off, and in particular, suitable for a case where IGZO-GDM is adopted; and a driving method of the liquid crystal display device. In the liquid crystal display device, when an OFF state of the power supply is detected, a power supply OFF sequence including an initialization step, a first discharge step and a second discharge step is executed. In the initialization step, only a clear signal (H_CLR) among GDM signals is set at a high level, and a state of each of bistable circuits which constitute a shift register is initialized. In the first discharge step, only the clear signal (H_CLR) among the GDM signals is set at a low level, all of gate bus lines are turned to a selected state, and electric charges in pixel formation portions are discharged.
    Type: Application
    Filed: August 9, 2012
    Publication date: October 16, 2014
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Kazuya Nakaminami, Satoshi Horiuchi
  • Publication number: 20140191935
    Abstract: The invention provides a liquid crystal display device that includes an IGZO-GDM which can quickly remove a residual charge in a panel when the power supply is turned off, and a driving method of the liquid crystal display device. Each bistable circuit that configures a shift register includes a thin film transistor TI for increasing a potential of an output terminal based on a first clock, a region netA connected to a gate terminal of the thin film transistor TI, a thin film transistor TC for lowering a potential of the region netA, and a region netB connected to a gate terminal of the thin film transistor TC. In such a configuration, a power supply off sequence includes a display off sequence and a gate off sequence. The gate off sequence includes at least a gate-bus-line discharge step (t14 to t15), a netB discharge step (t15 to t16), and a netA discharge step (t16 to t17).
    Type: Application
    Filed: August 3, 2012
    Publication date: July 10, 2014
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Hideki Morii, Akihisa Iwamoto, Satoshi Horiuchi, Takayuki Mizunaga, Kazuya Nakaminami
  • Patent number: 8749469
    Abstract: A display device, in at least one embodiment, includes: a gate driver including a plurality of shift register stages each provided so as to correspond to each row, the gate driver outputting a gate signal for turning on switching elements in the each row; and a source driver outputting a data signal in accordance with an image to be displayed. For a row (first row) located at an outermost position from which scanning by use of the gate signal starts, a dummy line is provided. The dummy line is driven by a gate start pulse inputted into a shift register in the first row.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: June 10, 2014
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Masahiro Hirokane, Yuuki Ohta
  • Publication number: 20140085278
    Abstract: In order to reduce the number of components forming a display device, a control IC 102 and a PC 104 are connected to an EEPROM 103 via an I2CBUS 106. The EEPROM 103 stores EDID data, and data stored in an LCD, which is used for control processing by the control IC 102.
    Type: Application
    Filed: May 1, 2012
    Publication date: March 27, 2014
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Masakazu Takeuchi, Chihiro Watanabe, Yasuki Mori, Akihisa Iwamoto
  • Patent number: 8531224
    Abstract: An object is shortening a clock fall-rise period while suppressing an increase in a circuit area, an increase in current consumption, and a cost increase, without generating an abnormal operation, in a shift register within a monolithic gate driver. In a shift register (410) that operates based on four-phase clock signals, including two-phase clock signals (GCK1, GCK3) that are provided to odd-order stages and two-phase clock signals (GCK2, GCK4) that are provided to even-order stages, of which phases are shifted by 90 degrees from each other, a potential of a first clock (CKA) appears as a potential of a scanning signal (GOUT), when a potential of a first node is at a high level, in each stage. In this configuration, the potential of the first node included in each stage is set to a high level based on a pulse of a scanning signal outputted from a pre-stage, and is set to a low level based on a pulse of a scanning signal outputted from a third stage after a stage concerned.
    Type: Grant
    Filed: July 15, 2010
    Date of Patent: September 10, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Shinya Tanaka, Tetsuo Kikuchi, Takaharu Yamada, Satoshi Horiuchi, Chikao Yamasaki, Kei Ikuta
  • Patent number: 8519764
    Abstract: Each stage that constitutes a shift register includes an output-control thin-film transistor for increasing a potential of a scanning signal based on a first clock (CKA), two thin-film transistors for increasing a potential of a first node connected to a gate terminal of the output-control thin-film transistor, based on a scanning signal outputted from a pre-stage/a latter stage, and two thin-film transistors for decreasing a potential of the first node, based on a scanning signal outputted from a third stage after/a third stage before a stage concerned. The shift register operates based on four-phase clock signals, including two-phase clock signals that are provided to odd-order stages and two-phase clock signals that are provided to even-order stages, of which phases are shifted by 90 degrees from each other.
    Type: Grant
    Filed: July 15, 2010
    Date of Patent: August 27, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Kei Ikuta
  • Publication number: 20130187843
    Abstract: Provided is a display device capable of correctly displaying an image when surplus outputs are produced within a driver, regardless of a shifting direction of a shift register within the driver, without bringing about increase in cost and increase in consumption current. A timing controller (200) is provided with a register (22) that can store data indicating the length of a horizontal back porch when a shifting direction of a shift register within a source driver (300) is in a forward direction and data indicating the length of the horizontal back porch when the shifting direction is in an inverse direction. A source-start-pulse generation unit (21) within the timing controller (200) refers to the data within the register (22) according to the shifting direction of the shift register, and generates one of a first source start pulse signal (SSP1) for the forward direction and a second source start pulse signal (SSP2) for the inverse direction.
    Type: Application
    Filed: October 17, 2011
    Publication date: July 25, 2013
    Applicant: SHARP KABUSHIKI KAISHA
    Inventor: Akihisa Iwamoto
  • Patent number: 8421724
    Abstract: A liquid crystal display device includes: scanning wires, provided so as to correspond to a plurality of pixels disposed in a matrix manner, to which scanning signals are applied; and signal wires to which data signals are applied, wherein the scanning wires and the signal wires cross each other. TFTs, electrically connected to the scanning wires and the signal wires, each of which is provided in the vicinity of an intersection of the scanning wire and the signal wire, and the TFTs are connected to pixel electrodes. A dummy pixel driven by a dummy signal wire is provided externally adjacent to an endmost pixel column. This brings about a matrix type liquid crystal display device that equalizes capacitive conditions of all the signal wires to each other and can prevent deterioration of display quality that is brought about by a specific portion differently displayed.
    Type: Grant
    Filed: September 22, 2009
    Date of Patent: April 16, 2013
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akihisa Iwamoto, Hideki Morii, Kazushige Miyamoto
  • Publication number: 20130057598
    Abstract: The present invention provides a display panel having decreased cost and current consumption by decreasing the number of data signal lines from the conventional number, a display device including the display panel, and a method of driving the display device. Each pixel formation portion (10) included in a display unit (200) of a display device is configured to arrange three sub-pixel formation portions (1r, 1g, 1b) for forming sub-pixels of mutually different color components in a data signal line extension direction. Each one data signal line (30) is arranged between a sub-pixel formation portion vertical string (3) in an odd-order from a front of a scanning signal line extension direction and a sub-pixel formation portion vertical string (3) adjacent to the sub-pixel formation portion vertical string (3) at the back of the scanning signal line extension direction. Sub-pixel formation portion vertical strings (3, 3) positioned at both sides of each data signal line (30) are connected to the data signal line.
    Type: Application
    Filed: April 18, 2011
    Publication date: March 7, 2013
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Kei Ikuta
  • Publication number: 20130027104
    Abstract: An object of the present invention is to provide a level shift IC with a reduced number of input signals over the conventional case. A level shift IC includes an amplitude converting unit including four level shifters; and a different-phase signal generating unit at a stage previous to the amplitude converting unit, including delay circuits. The different-phase signal generating unit generates, by the delay circuits, first and second delayed input signals from first and second input signals of different phases. Therefore, four input signals of different phases are obtained, and the amplitude converting unit increases the amplitudes of the input signals by the amplitude converting unit and thereby generates first to fourth output signals with different phases and increased amplitudes.
    Type: Application
    Filed: January 26, 2011
    Publication date: January 31, 2013
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Yuuki Ohta, Hideki Morii, Akihisa Iwamoto, Takayuki Mizunaga
  • Publication number: 20120223926
    Abstract: An object is to provide at low cost a Power-supply circuit that can generate positive and negative analog power source voltages of which absolute values of voltage values are equal. A Power-supply circuit (210) is configured by a DCDC converter circuit (212) and a charge pump circuit (214). The charge pump circuit (214) includes a diode (D3) that passes a current when a control switch (51) is in an off state, and a diode (D4) that passes a current when the control switch (51) is in an on state. A DCDC converter circuit (212) includes two diodes (D1, D2) that pass a current when the control switch (S1) is in an off state. A rectifying unit that includes the diodes (D1, D2) is configured such that a forward drop voltage of the rectifying unit becomes equal to a sum of a forward drop voltage of the diode (D3) and a forward drop voltage of the diode (D4).
    Type: Application
    Filed: July 7, 2010
    Publication date: September 6, 2012
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Hideki Morii, Akihisa Iwamoto, Takayuki Mizunaga, Kei Ikuta
  • Publication number: 20120218245
    Abstract: A liquid crystal display device includes a monolithic gate driver capable of quickly eliminating residual charges within pixel formation portions when the power-supply is turned off. Each of bistable circuits that constitute a shift register within a gate driver is provided with a thin-film transistor having a drain terminal connected to a gate bus line, a source terminal connected to a reference potential line for transmitting a reference potential, and a gate terminal to which a clock signal for operating the shift register is supplied. When the external supply of power-supply voltage is cut off, the clock signal is set to high level to turn the thin-film transistor to the ON state, and the level of the reference potential is increased from a gate-OFF potential to a gate-ON potential.
    Type: Application
    Filed: August 27, 2010
    Publication date: August 30, 2012
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Hideki Morii, Akihisa Iwamoto, Takayuki Mizunaga, Yuuki Ohta
  • Patent number: 8248337
    Abstract: In one embodiment of the present invention, a video signal processing method is disclosed wherein video correction data is read from a ROM and written into an LUT, and the video correction data written in the LUT is used to perform data correction of an externally inputted video signal. The video correction data written in the LUT is updated during the horizontal blanking interval of the video signal.
    Type: Grant
    Filed: May 19, 2006
    Date of Patent: August 21, 2012
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Masakazu Takeuchi, Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga
  • Publication number: 20120200544
    Abstract: In a shift register that operates based on four-phase clock signals, including two-phase clock signals that are provided to odd-order stages and two-phase clock signals that are provided to even-order stages, of which phases are shifted by 90 degrees from each other, a potential of a first clock appears as a potential of a scanning signal, when a potential of a first node is at a high level, in each stage. In this configuration, the potential of the first node included in each stage is set to a high level based on a pulse of a scanning signal outputted from a pre-stage, and is set to a low level based on a pulse of a scanning signal outputted from a third stage after a stage concerned.
    Type: Application
    Filed: July 15, 2010
    Publication date: August 9, 2012
    Applicant: SHARP KABUSHIKI KAISHA
    Inventors: Akihisa Iwamoto, Hideki Morii, Takayuki Mizunaga, Shinya Tanaka, Tetsuo Kikuchi, Takaharu Yamada, Satoshi Horiuchi, Chikao Yamasaki, Kei Ikuta