Optical Cards

Optical memory cards use a technology similar to the one used for music CDs or CD ROMs. A panel of the "gold colored" laser sensitive material is laminated in the card and is used to store the information.

The material is comprised of several layers that react when a laser light is directed at them. The laser burns a tiny hole (2.25 microns in diameter) in the material which can then be sensed by a low power laser during the read cycle. The presence or absence of the burn spot indicates a "one" or a "zero". Because the material is actually burned during the write cycle, the media is a write once read many (WORM) media and the data is non volatile (not lost when power is removed).

The optical card can currently store between 4 and 6.6 MB of data which gives the ability to store graphical images such as photographs, logos, fingerprints, x-rays, etc.. The data is encoded in a linear x-y format and ISO/IEC 11693 and 11694 standards cover the details.

Reprinted with permission from AIM, Inc.
www.aimglobal.org

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