Patents by Inventor Shinobu Tokunaga

Shinobu Tokunaga 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).

  • Optical glass for optical paths
    Patent number: 4297141
    Abstract: The present invention relates to an optical glass for an optical path, having a refractive index of at least 1.55, an Abbe number of at least 48 and a specific gravity of at most 2.90 and being excellent in chemical durability, having a chemical composition of:______________________________________ SiO.sub.2 55 to 65% by weight B.sub.2 O.sub.3 0 to 10 TiO.sub.2 + ZrO.sub.2 1 to 5 TiO.sub.2 0 to 5 ZrO.sub.2 0 to 5 CaO + ZnO 20 to 33 CaO 5 to 20 ZnO 3 to 20 Al.sub.2 O.sub.3 0 to 4 one or more of R.sub.2 O (Li.sub.2 O, Na.sub.2 O, K.sub.2 O) 5 to 9 As.sub.2 O.sub.
    Type: Grant
    Filed: November 19, 1980
    Date of Patent: October 27, 1981
    Assignee: Sumita Optical Glass Manufacturing Co., Ltd.
    Inventors: Shinobu Tokunaga, Yuichi Shiina