The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 17, 1978
Filed:
Sep. 27, 1976
Nils Abramson, Stockholm, SE;
Hans Bjelkhagen, Stockholm, SE;
AB ID-kort, Stockholm, SE;
Abstract
A method for establishing and reading secret information using holographic interference pattern techniques. A holographic plate is placed in a holder and exposed with a laser light reflected from an object and a reference laser light to create a hologram. The exposed hologram is removed and a second holographic plate is inserted into the holder. The object, which may be a matrix, is selectively deformed to provide letters or numbers in accordance with the secret information to be established. The second holographic plate is then exposed with a light reflected from the deformed object and with the reference laser light to create a second hologram. The information contained on each hologram, when viewed individually, appears to be substantially identical. However, when the two holograms are later combined and illuminated, the secret information in the form of a holographic interference pattern will be observed in the hologram.