Patents by Inventor Ji-Su CHOI

Ji-Su CHOI 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).

  • Digital-to-analog converter and driving circuit of display device having the same
    Patent number: 10735011
    Abstract: A digital-to-analog converter having a structure that converter may decrease an effect of a mismatch between elements and decrease a quantity of the elements. The digital-to-analog converter includes a multiplexer configured to output a first voltage or a second voltage corresponding to an input bit as an input voltage and a recursive switched circuit configured to alternately receive the input voltage and a reference voltage and to output an average value of the input voltage and the reference voltage as an output voltage.
    Type: Grant
    Filed: June 7, 2018
    Date of Patent: August 4, 2020
    Assignees: SAMSUNG DISPLAY CO., LTD., KOREA ADVANCED INSTITUTE OF SCIENCE AND TECHNOLOGY
    Inventors: Ohjo Kwon, Gyu-Hyeong Cho, Ki-Duk Kim, Ji-Su Choi
  • DIGITAL-TO-ANALOG CONVERTER AND DRIVING CIRCUIT OF DISPLAY DEVICE HAVING THE SAME
    Publication number: 20180358975
    Abstract: A digital-to-analog converter having a structure that converter may decrease an effect of a mismatch between elements and decrease a quantity of the elements. The digital-to-analog converter includes a multiplexer configured to output a first voltage or a second voltage corresponding to an input bit as an input voltage and a recursive switched circuit configured to alternately receive the input voltage and a reference voltage and to output an average value of the input voltage and the reference voltage as an output voltage.
    Type: Application
    Filed: June 7, 2018
    Publication date: December 13, 2018
    Inventors: Ohjo KWON, Gyu-Hyeong CHO, Ki-Duk KIM, Ji-Su CHOI
  • Method for preparing a pitch for carbon fibers and a pitch for carbon fibers prepared by the same
    Patent number: 9403936
    Abstract: A method for preparing a pitch for carbon fibers and a pitch for carbon fibers prepared by the same are disclosed. The method includes introducing a peroxide compound and ozone into a petroleum-process residual oil, followed by heat treatment for reaction. By the method, the pitch for carbon fibers, which exhibits excellent oxidative stabilization and oxidative incompatibility while having a high softening point and high strength, can be obtained at high yield at a relatively low temperature.
    Type: Grant
    Filed: September 30, 2014
    Date of Patent: August 2, 2016
    Assignee: GS CALTEX CORPORATION
    Inventors: Sang-Wook Park, Young-Se Oh, Ji-Su Choi, Ki-Ung Kim, Sang-Hee Park
  • METHOD FOR PREPARING A PITCH FOR CARBON FIBERS AND A PITCH FOR CARBON FIBERS PREPARED BY THE SAME
    Publication number: 20160090441
    Abstract: A method for preparing a pitch for carbon fibers and a pitch for carbon fibers prepared by the same are disclosed. The method includes introducing a peroxide compound and ozone into a petroleum-process residual oil, followed by heat treatment for reaction. By the method, the pitch for carbon fibers, which exhibits excellent oxidative stabilization and oxidative incompatibility while having a high softening point and high strength, can be obtained at high yield at a relatively low temperature.
    Type: Application
    Filed: September 30, 2014
    Publication date: March 31, 2016
    Inventors: Sang-Wook PARK, Young-Se OH, Ji-Su CHOI, Ki-Ung KIM, Sang-Hee PARK