Patent ID: 7710623

Claim:
A method for making a security hologram comprising a covert image of an object, said method comprising the steps of: a) placing the object in contact with a first face of a prism, placing a first photosensitive film in contact with a second face of the prism, and holographically exposing the object, the prism and the first photosensitive film to a first coherent beam of electromagnetic radiation that is incident upon a third face of the prism wherein the first photosensitive film results in a first exposed photosensitive film having a H1 hologram of the object; b) curing the first exposed photosensitive film with electromagnetic radiation resulting in a first cured photosensitive film and removing the object from being proximate to the prism; and c) placing a second photosensitive film in contact with the first face of the prism, exposing the first cured photosensitive film, the prism and the second photosensitive film to a second coherent beam of electromagnetic radiation that is incident upon the third face of the prism wherein the second photosensitive film results in a second exposed photosensitive film having a H2 hologram , and curing the second photosensitive film with electromagnetic radiation resulting in a second cured photosensitive film, wherein the holographic imaging in step c) is effected using a single coherent beam of electromagnetic radiation in combination with a Lloyd's mirror to provide both reference and object beams.