PRODUCTION OF NON-DUPLICABLE HOLOGRAM HAVING CHARACTERISTIC POINT OF GENUINE OBJECT AND READER FOR CHECKING AUTHENTICITY

摘要

PROBLEM TO BE SOLVED: To make a hologram usable as a certificate for the genuineness of articles and documents of any types and to check the authenticity thereof with high reliability by photographing the hologram having the optical elements of random structures forming the genuine characteristic points of the hologram having stripe patterns. SOLUTION: A laser beam 1 passes a cylindrical lens 2 and forms object light in the form of a line on a focusing glass screen 3 corresponding to the optical elements having the random structures. A Fourier lens 6 is placed between this focusing glass screen 3 and a hologram plate 5 consisting of a photosensitive material in a position where the distances from both are equal and are (f). This Fourier lens 6 changes the object light condensed to the line on the focusing glass screen 3 to parallel wave fronts 7. These parallel wave fronts 7 interfere with reference light 8 on the photosensitive material of the hologram plate 5 and the hologram of the parallel lines having the stripe patterns formed of the different space frequency is recorded on the photosensitive material.