IDENTIFICATION SYSTEM USING REFERENCE BEAM CODED HOLOGRAMS

• US 3,647,275 A
• Filed: 09/09/1970
• Issued: 03/07/1972
• Est. Priority Date: 09/09/1970
• Status: Expired due to Term

• Current Assignee: Intergraph Corporation One Madison Industrial Park Huntsville Alabama 35807
• Original Assignee: John H. Ward
• Inventors: Ward, John H.
• Primary Examiner(s): Schonberg, David
• Assistant Examiner(s): Stern, Ronald J.
• Application Number:
  US05/070,762
• Time in Patent Office: 545 Days
• Field of Search: 350/3.5 35/2
• US Class Current: 380/54
• CPC Class Codes: G03H 1/041 Optical element in the object space affecting the object beam, not otherwise provided for
• CPC Class Codes: Y10S 283/904 Credit card

Abstract

An identification system for identifying persons, articles, documents and the like using a coded hologram which contains the desired identifying indicia in coded holographic form. Encoding of the identifying indicia in the hologram is accomplished by means of a beam scrambler which introduces random path distances in either the reference or object beam during the formation of the hologram. The same or identical beam scrambler is used during reconstruction of the hologram to decode the identifying indicia. The identification system can be used for credit cards and personal access I.D. cards. Typical identifying indicia includes the user'"'"''"'"'s name, signature, and photograph.

Claims

2. introducing the same random path distances in said reference light beam by using the same or an identical beam scrambler to that which was used in forming the hologram;

3. passing only said reference light beam through a beam scrambler to introduce random path distances iN said reference light beam;

4. positioning the coded hologram at the focused image of said beam scrambler;

and thereafter,

5. imaging said beam scrambler onto said photosensitive member;

6. The method of claim 5 wherein said beam scrambler random surface deformations are formed by molding said beam scrambler in a mold having complementary random surface deformations.

7. directing at least a portion of the object-modified light onto the photosensitive member, said object-modified light being sufficiently coherent with respect to the reference light beam to produce an interference pattern on said photosensitive member.

8. The method of claim 1 wherein said reference light beam is passed through a beam scrambler which has random variations in its index of refraction.

9. The method of claim 2 wherein said object is imaged at a location other than the location of said photosensitive member.

10. The method of claim 9 wherein the object image is located behind said photosensitive member.

11. A method of reconstructing a coded hologram that was encoded by a beam scrambler which introduced random path distances only in the reference beam and which was imaged upon the hologram during the formation thereof, said hologram reconstruction comprising the steps of:

12. The method of claim 11 wherein the image of said beam scrambler is formed by an afocal lens system.