Patents Examined by Edmondson
  • Optically diffracting security element
    Patent number: 4662653
    Abstract: A security element for authenticating bank notes, credit cards, security passes and the like is disclosed. The security element incorporates a reflective-type diffraction grating, which grating comprises a continuous layer of reflecting material on which is deposited a layer of dielectric material. Non-continuous reflecting layer portions are embedded in the dielectric material. It is practically impossible to lay bare the diffraction grating without destroying it.
    Type: Grant
    Filed: December 14, 1984
    Date of Patent: May 5, 1987
    Assignee: LGZ Landis & Gyr Zug AG
    Inventor: David L. Greenaway