Optical cryptographic device

• US 3,166,625 A
• Filed: 02/07/1962
• Issued: 01/19/1965
• Est. Priority Date: 02/07/1962
• Status: Expired due to Term

• Current Assignee: Corwin H. Brumley
• Original Assignee: Corwin H. Brumley
• Inventors: Brumley, Corwin H.
• Application Number:
  US04/171,661
• Time in Patent Office: 1,077 Days
• US Class Current: 380/54
• CPC Class Codes: G02B 27/025 and magnifying means

Claims

1. AN OPTICAL CRYPTOGRAPHIC DEVICE COMPRISING MEANS DEFINING A LIMITED FIELD IN A SELECTED OBJECT PLANE, AND A SCREEN COMPRISING RELATIVELY SMALL OPTICAL IMAGE FORMING ELEMENTS WHICH ARE SMALL RELATIVE TO SAID FIELD AND SPACED FROM SAID FIELD AT AN OBJECT DISTANCE, EACH OF THE ELEMENTS OF SAID SCREEN FORMING AERIAL IMAGES OF RELATIVELY SMALL PORTIONS OF SAID FIELD AT AN IMAGE DISTANCE WHICH IS CONJUGATE TO SAID OBJECT DISTANCE WHEREBY THE AERIAL IMAGES FORMED BY SAID SCREEN ARE DIFFERENTIALLY ORIENTED RELATIVE TO EACH OTHER FROM THE RELATIVE ORIENTATIONS OF THE CORRESPONDING RESPECTIVE PORTIONS OF SAID FIELD, A SECOND SCREEN OF OPTICAL IMAGE FORMING ELEMENTS WHICH ARE SMALL RELATIVE TO SAID FIELD AND SPACED FROM SAID FIRST SCREEN AT A SECOND OBJECT DISTANCE, EACH OF SAID ELEMENTS OF SAID SECOND SCREEN FORMING AERIAL IMAGES OF A PORTION OF THE AERIAL IMAGE FORMED BY SAID FIRST SCREEN WHEREBY THE AERIAL IMAGES FORMED BY SAID SECOND SCREEN ARE DIFFERENTIALLY ORIENTED RELATIVE TO EACH OTHER FROM THE RELATIVE ORIENTATIONS OF THE CORRESPONDING RESPECTIVE PORTIONS OF SAID FIRST AERIAL IMAGES, A SELECTED IMAGE PLANE AND MEANS FOR REALYING THE AERIAL IMAGES FORMED BY SAID SECOND SCREEN TO SAID IMAGE PLANE.