Patents Assigned to John S. Ewald
  • Ultraviolet sensing device
    Patent number: 4061922
    Abstract: The ultraviolet sensing device disclosed herein employs a visible light sensitive photoconductive cell which is protected from direct exposure to ultraviolet light by a housing. Ultraviolet light entering the housing through a quartz window illuminates a fluorescent material and the photoconductive cell is oriented so as to receive visible light given off by the fluorescent material while being shielded from the direct ultraviolet rays.
    Type: Grant
    Filed: May 17, 1976
    Date of Patent: December 6, 1977
    Assignee: John S. Ewald
    Inventor: Anthony J. Last