Patents by Inventor Kiyoshi Yasumura

Kiyoshi Yasumura 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).

  • Polyester film for magnetic recording tape
    Patent number: 4840830
    Abstract: A polyester film suitable for use as the magnetic tape base for video recording, capable of high density recording and having stable slidability or running characteristics. The polyester film is made of a polyester which contains 0.05-1 wt % particles containing calcium and phosphorus and of which the number n of the second interference fringes (number/mm.sup.2) and the average centerline roughness (.mu.m) satisfy the following relationships:n<30 (1)0.005.ltoreq.R.sub.a .ltoreq.0.
    Type: Grant
    Filed: October 6, 1987
    Date of Patent: June 20, 1989
    Assignee: Diafoil Company, Limited
    Inventors: Seiji Sakamoto, Kiyoshi Yasumura