Patents Assigned to Kirk Optical Lens Co., Inc.
  • Method to test for chemically hardened glass lenses
    Patent number: 4035082
    Abstract: A device to test for the presence of chemically hardened glass wherein a collimated light source and a windowed container are filled with a fluid of refractive index substantially equalling that of the glass. The glass is immersed in the container with the container placed between crossed polarizers. When the glass is chemically hardened, light traversing therethrough is refractively bent thereby to produce a component of the light vector in the optical axis of one of the polarizers and an observable light pattern emanating therefrom.
    Type: Grant
    Filed: April 7, 1975
    Date of Patent: July 12, 1977
    Assignee: Kirk Optical Lens Co., Inc.
    Inventor: Morris Kirschen