Photoelectric apparatus for detecting altered markings
Multiple image encoding using surface relief structures as authenticating device for sheet-material authenticated item
Secure and self-verifiable image Patent #: 4632430
ApplicationNo. 06/918921 filed on 10/15/1986
US Classes:283/70, Identifying283/904, CREDIT CARD283/91Specific spectral transmittance or reflectance
ExaminersPrimary: Bell, Paul A.
Attorney, Agent or Firm
International ClassesG07D 7/00 (20060101)
G07F 7/08 (20060101)
G06K 19/14 (20060101)
Foreign Application Priority Data1985-10-15 DE
AbstractThe present invention relates to a data carrier (identification card, bank card, credit card, etc.) in which information is provided in an inner volume area by means of a laser beam, the information being visible in the form of changes in the optical properties of the carrier material due to an irreversible change in the material caused by the laser beam and to a method for producing the data carrier and for testing it.