Patents by Inventor Kei Tokui

Kei Tokui 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: 7372758
    Abstract: A memory cell array employs a memory element as a memory cell. The memory element is constructed of a gate electrode formed via a gate insulation film on a semiconductor layer, a channel region arranged under the gate electrode, diffusion regions that are arranged on both sides of the channel region and have a conductive type opposite to that of the channel region, and memory function bodies that are arranged on both sides of the gate electrode and have a function to retain electric charges. When first and second power voltages VCC1 and VCC2 supplied from the outside are lower than a prescribed voltage, a rewrite command to a memory circuit 34 that includes the memory cell array is inhibited by a lockout circuit 33a.
    Type: Grant
    Filed: October 2, 2003
    Date of Patent: May 13, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshifumi Yaoi, Hiroshi Iwata, Akihide Shibata, Kei Tokui, Masaru Nawaki
  • Patent number: 7203118
    Abstract: When an input voltage determining circuit 24 determines that an input voltage exceeds a prescribed voltage, a control circuit 25 of a positive polarity power selector circuit 22 turns on a first switch SW1 and turns off second and third switches SW2 and SW3, thereby supplying the input voltage to a memory cell array 21 via the first switch SW1. When the input voltage determining circuit 24 determines that the input voltage is not higher than the prescribed voltage, the control circuit 25 turns off the first switch SW1 and turns on the second and third switches SW2 and SW3, thereby supplying a voltage from a charge pump 23 via the second and third switches SW2 and SW3. By this operation, the memory element is able to retain storage of two bits or more even if miniaturized, to execute stable operation with a small circuit area and to prevent circuit malfunction attributed to a small current supplied to the memory cell array.
    Type: Grant
    Filed: September 10, 2003
    Date of Patent: April 10, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Yoshifumi Yaoi, Hiroshi Iwata, Akihide Shibata, Masaru Nawaki, Kei Tokui
  • Publication number: 20070008458
    Abstract: In a display device of the invention, driving of the piezoelectric element is controlled to change the light path of the propagating light inside a light guiding plate. By illuminating a liquid crystal panel in this manner, an illumination time and a no illumination time can be provided for the liquid crystal panel within one frame period. This realizes impulse-type-like display in displaying moving images on the liquid crystal panel, and thereby improves an image quality of moving images. Further, since the light is used only in desired regions, spontaneous luminance can be improved and the light can be used more efficiently.
    Type: Application
    Filed: April 28, 2004
    Publication date: January 11, 2007
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Kei Tokui, Kenichi Iwauchi
  • Publication number: 20060244049
    Abstract: A memory cell array employs a memory element as a memory cell. The memory element is constructed of a gate electrode formed via a gate insulation film on a semiconductor layer, a channel region arranged under the gate electrode, diffusion regions that are arranged on both sides of the channel region and have a conductive type opposite to that of the channel region, and memory function bodies that are arranged on both sides of the gate electrode and have a function to retain electric charges. When first and second power voltages VCC1 and VCC2 supplied from the outside are lower than a prescribed voltage, a rewrite command to a memory circuit 34 that includes the memory cell array is inhibited by a lockout circuit 33a.
    Type: Application
    Filed: October 2, 2003
    Publication date: November 2, 2006
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshifumi Yaoi, Hiroshi Iwata, Akihide Shibata, Kei Tokui, Masaru Nawaki
  • Publication number: 20060109729
    Abstract: When an input voltage determining circuit 24 determines that an input voltage exceeds a prescribed voltage, a control circuit 25 of a positive polarity power selector circuit 22 turns on a first switch SW1 and turns off second and third switches SW2 and SW3, thereby supplying the input voltage to a memory cell array 21 via the first switch SW1. When the input voltage determining circuit 24 determines that the input voltage is not higher than the prescribed voltage, the control circuit 25 turns off the first switch SW1 and turns on the second and third switches SW2 and SW3, thereby supplying a voltage from a charge pump 23 via the second and third switches SW2 and SW3. By this operation, the memory element is able to retain storage of two bits or more even if miniaturized, to execute stable operation with a small circuit area and to prevent circuit malfunction attributed to a small current supplied to the memory cell array.
    Type: Application
    Filed: September 10, 2003
    Publication date: May 25, 2006
    Applicant: Sharp Kabushiki Kaisha
    Inventors: Yoshifumi Yaoi, Hiroshi Iwata, Akihide Shibata, Masaru Nawaki, Kei Tokui
  • Patent number: 7038282
    Abstract: A semiconductor storage device includes a voltage supply circuit generating a voltage of 5V, a voltage polarity inversion circuit generating a voltage of ?5V, a select-and-connect circuit supplying the voltages of 5V and ?5V to a memory cell array, a 5 V voltage level detection circuit detecting the voltage derived from the voltage supply circuit, and a ?5 V voltage level detection circuit detecting the voltage derived from the voltage polarity inversion circuit. Absolute values of the voltages detected by the voltage level detection circuits are lower than ever before. This allows a gate insulation film to be thinner. A memory-function film is formed on both sides of a gate electrode in the semiconductor storage device. This also make the gate insulation film thinner. The thin gate insulation film suppresses the short-channel effect, so that each memory element of the memory cell array is miniaturized.
    Type: Grant
    Filed: February 4, 2004
    Date of Patent: May 2, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kei Tokui, Hiroshi Iwata, Yoshifumi Yaoi, Akihide Shibata, Masaru Nawaki
  • Patent number: 6985397
    Abstract: A semiconductor storage device has a variable-stage charge pump, and a memory cell array to which an output from an output line of the variable-stage charge pump is fed. In the variable-stage charge pump, first and second charge pumps are connected in parallel between a common input bus and a common output bus. A first n-channel MOSFET is provided on a line connecting an output terminal of the first charge pump and the common output bus, and another n-channel MOSFET is provided on a line connecting the second charge pump and the common output bus. First switches are provided between the output terminal of the first charge pump and the first n-channel MOSFET, and between the input terminal of the second charge pump and the second switch. A second switch is provided on a line connecting an input terminal of the second charge pump and the common input bus.
    Type: Grant
    Filed: March 25, 2004
    Date of Patent: January 10, 2006
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Kei Tokui, Hiroshi Iwata, Yoshifumi Yaoi, Akihide Shibata, Masaru Nawaki
  • Publication number: 20050232573
    Abstract: A display device includes an illuminating device having an optical waveguide plate for introducing light thereinto, a drive assembly having a planar array of actuators disposed in facing relation to the optical waveguide plate, a displacement transmitter assembly disposed between the optical waveguide plate and the drive assembly, and a light scattering layer disposed on the displacement transmitter assembly. The actuators are selectively displaceable to bring the light scattering layer into and out of contact with the optical waveguide plate, for controlling light that leaks from the optical waveguide plate as emitted light. The display device also includes an optical modulator for modulating the emitted light from the illuminating device to display an image. The illuminating device has a light reflecting layer disposed on at least a portion of the displacement transmitter assembly that confronts the optical waveguide plate.
    Type: Application
    Filed: March 17, 2005
    Publication date: October 20, 2005
    Applicants: Sharp Kabushiki Kaisha, NGK Insulators, Ltd.
    Inventors: Kenichi Iwauchi, Kei Tokui, Yukihisa Takeuchi, Tsutomu Nanataki, Natsumi Shimogawa, Isao Shikata
  • Publication number: 20040190361
    Abstract: A semiconductor storage device has a variable-stage charge pump, and a memory cell array to which an output from an output line of the variable-stage charge pump is fed. In the variable-stage charge pump, first and second charge pumps are connected in parallel between a common input bus and a common output bus. A first n-channel MOSFET is provided on a line connecting an output terminal of the first charge pump and the common output bus, and another n-channel MOSFET is provided on a line connecting the second charge pump and the common output bus. First switches are provided between the output terminal of the first charge pump and the first n-channel MOSFET, and between the input terminal of the second charge pump and the second switch. A second switch is provided on a line connecting an input terminal of the second charge pump and the common input bus.
    Type: Application
    Filed: March 25, 2004
    Publication date: September 30, 2004
    Inventors: Kei Tokui, Hiroshi Iwata, Yoshifumi Yaoi, Akihide Shibata, Masaru Nawaki
  • Publication number: 20040164343
    Abstract: A semiconductor storage device includes a voltage supply circuit generating a voltage of 5V, a voltage polarity inversion circuit generating a voltage of −5V, a select-and-connect circuit supplying the voltages of 5V and −5V to a memory cell array, a 5 V voltage level detection circuit detecting the voltage derived from the voltage supply circuit, and a −5 V voltage level detection circuit detecting the voltage derived from the voltage polarity inversion circuit. Absolute values of the voltages detected by the voltage level detection circuits are lower than ever before. This allows a gate insulation film to be thinner. A memory-function film is formed on both sides of a gate electrode in the semiconductor storage device. This also make the gate insulation film thinner. The thin gate insulation film suppresses the short-channel effect, so that each memory element of the memory cell array is miniaturized.
    Type: Application
    Filed: February 4, 2004
    Publication date: August 26, 2004
    Inventors: Kei Tokui, Hiroshi Iwata, Yoshifumi Yaoi, Akihide Shibata, Masaru Nawaki