Secure card and sensing system
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Apr 7, 1987
Grant Date -
N/A
app pub date -
Oct 4, 1984
filing date -
Oct 4, 1984
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
An identification card is disclosed as for supporting commercial or other significant transactions involving a designated subject. The card incorporates a machine-readable record and is produced with an individual birefringent characteristic to modulate a light beam for card identification. In one embodiment, the card incorporates apparent stress waves to modulate an orientation-frequency characteristic (e.g. polarization angle) of a light beam. The machine-readable record on the card indicates the characteristic birefringence for confirming the card to be authentic. Methods are disclosed for producing and testing the cards. A system is disclosed for sensing card characteristics by modulated light including polarized light techniques to record and verify the cards with allowance for changes, as by card aging.
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