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CE TEXTE S'AFFICHERA PENDANT SECONDES. LISEZ-LE ET ESSAYEZ DE RETENIR UN MAXIMUM
Clearly Trendier
French smartcard maker Gemplus thinks bank and credit cards would
look more trendy if they were made transparent. This is easier said than done
because cash machines and phone booths rely on the card being opaque to infrared
light. So Gemplus has designed a card with filters that block infrared light
but let through visible light.
Its trick is to embed several layers of filtering dyes, each of which blocks
a different part of the spectrum in the range 700 to 1000 nanometres. The
result? To the eye, the card looks transparent, but to a card reader it looks
jet black.