Patents Assigned to Etat Francias
  • Band filters for use in protective glasses
    Patent number: 4045125
    Abstract: A band filter adapted to pass only a band of determined wave length of the electromagnetic spectrum and comprising a support, at least partially transparent in the considered band, covered on one of its surfaces by a filtering element constituted of three metallic layers separated respectively by two layers of transparent material. The filter can employ anti-reflection coatings and binding and adherency layers.
    Type: Grant
    Filed: June 23, 1975
    Date of Patent: August 30, 1977
    Assignee: Etat Francias
    Inventor: Guy Farges