Patents Assigned to Naoetsu Precision Co., Ltd.
  • Internally marked quartz glass, quartz glass substrate for optical member, and marking method
    Patent number: 6744458
    Abstract: In a quartz glass, a mark is internally made such that a retardation generated in close proximity to the end of the mark is up to 20 nm. The internally marked quartz glass in which internal marks are created without sacrificing optical precision finds use as quartz glass substrates for optical members in the electronic industry.
    Type: Grant
    Filed: September 13, 2002
    Date of Patent: June 1, 2004
    Assignees: Shin-Etsu Chemical Co., Ltd., Naoetsu Precision Co., Ltd.
    Inventors: Motoyuki Yamada, Koji Yamaga