US Patent 7198302 Card-shaped data carrier and method for producing same

The invention relates to a card-shaped data carrier consisting of at least one layer (1, 2, 3). Visually readable information in the form of a changed optical characteristic is introduced into the layer. Said characteristic is changed by irreversibly changing the material by means of a laser beam. The absorption capacity of said layer (1, 2, 3) for at least one wavelength (λ±λ) is at least partially reduced due to the laser radiation.