Patents by Inventor Kenji Nakagaqa

Kenji Nakagaqa 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).

  • Glass for photoetching mask
    Patent number: 4403043
    Abstract: A glass composition for a photoetching mask is described, which comprises, all by mol, 55 to 70% SiO.sub.2, 7 to 11% Al.sub.2 O.sub.3, 7 to 20% CaO, 3 to 13% MgO, 3 to 13% ZnO, 0.5 to 3% K.sub.2 O or Na.sub.2 O, 0 to 11% PbO and 0 to 3% ZrO.sub.2. This glass is free from defects such as pinholes, has a relatively low coefficient of thermal expansion and contains no air bubbles, and a photoetching mask composed of the glass composition.
    Type: Grant
    Filed: August 31, 1982
    Date of Patent: September 6, 1983
    Assignee: Hoya Corporation
    Inventors: Kenji Nakagaqa, Isao Masuda