Patents by Inventor Archie E. Barkdoll

Archie E. Barkdoll 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).

  • Contact lens having a hard center and soft, tough periphery
    Patent number: 3944347
    Abstract: Disclosed is a segmented contact lens for the human eye constructed from fluorine-containing polymers, said lens having an index of refraction approximating that of tears and being characterized by a hard center segment surrounded by a soft tough periphery, the hard center having a Knoop hardness of at least 2 and the soft, tough periphery having a Clash-Berg torsion modulus of 95-1,000 lb/sq. in.
    Type: Grant
    Filed: February 26, 1974
    Date of Patent: March 16, 1976
    Assignee: E. I. Du Pont de Nemours & Co.
    Inventors: Archie E. Barkdoll, David C. England
  • Soft, tough low refractive index contact lenses
    Patent number: 3940207
    Abstract: Disclosed is a soft, tough, contact lens for the human eye constructed of fluorine-containing polymers, said lens having a Clash-Berg torsion modulus of 95-1000 lb/sq. in. and a refractive index approximating that of human tears.
    Type: Grant
    Filed: February 26, 1974
    Date of Patent: February 24, 1976
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Archie E. Barkdoll