| 摘要 |
1515652 Holograms SIEMENS AG 31 Jan 1977 [26 March 1976] 03862/77 Heading G2J [Also in Division B6] A card with a non-transparent base bears printed information and, contained in a major portion of a carrier layer covering one side, a Hippmann-Bragg hologram containing checking information. Preferably the hologram covers one side of the base, includes both analogue and binary information and has in it analogue information identical in content to part of the printed information. Methods of imaging the card holographically and of reading out the information in the card with coherent and incoherent light are described. Preferably the hologram is carried on the rear of the card, and the stored data in it is a reproduction of the front of the card. |
