Patents by Inventor Yi Sik Choi

Yi Sik 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).

  • Patent number: 9988741
    Abstract: Provided is a sapphire single crystal heat treatment method comprising the steps of: charging a sapphire single crystal into a chamber; raising the temperature in the chamber to a target temperature by heating the chamber; holding the temperature in the chamber at a constant temperature; and cooling the inside of the chamber to room temperature, wherein the temperature raising step comprises: a first temperature raising step of raising the temperature to a first set temperature at a temperature raising rate of 4° C./min to 5° C./min; and a second temperature raising step of raising the temperature to a second set temperature at a temperature raising rate of 1° C./min or less after the first temperature raising step has been completed. The temperature raising process is executed in a multi-stage, to reduce the temperature raising time and prevent a sapphire single crystal from being affected by heat.
    Type: Grant
    Filed: September 10, 2013
    Date of Patent: June 5, 2018
    Assignee: SAPPHIRE TECHNOLOGY CO., LTD.
    Inventors: Hee Choon Lee, Yi Sik Choi, Sung Hwan Moon, Gye Won Jang, Bok Kee Na
  • Publication number: 20150267321
    Abstract: Provided is a sapphire single crystal heat treatment method comprising the steps of: charging a sapphire single crystal into a chamber; raising the temperature in the chamber to a target temperature by heating the chamber; holding the temperature in the chamber at a constant temperature; and cooling the inside of the chamber to room temperature, wherein the temperature raising step comprises: a first temperature raising step of raising the temperature to a first set temperature at a temperature raising rate of 4° C./min to 5° C./min; and a second temperature raising step of raising the temperature to a second set temperature at a temperature raising rate of 1° C./min or less after the first temperature raising step has been completed. The temperature raising process is executed in a multi-stage, to reduce the temperature raising time and prevent a sapphire single crystal from being affected by heat.
    Type: Application
    Filed: September 10, 2013
    Publication date: September 24, 2015
    Inventors: Hee Choon Lee, Yi Sik Choi, Sung Hwan Moon, Gye Won Jang, Bok Kee Na