DATA MEDIA

The invention relates to data media, whereby various data protection techniques may be used during the production of said data in order to protect the data media against unauthorized copies or tampering. The data medium (1) is a multilayer structure carrying graphic and alphanumeric information (8) and made from a thin layer material, which includes at least one layer (4) comprising an identification area (7), whereby said area is divided into segments which are transparent with respect to light (10), allow for modulation of the light flow and are limiting strips (11). Said strips, discrete or continuous, are made of a material which is non transparent with respect to light flow throughout the entire thickness or a part thereof. The ratio between the thickness of the limiting strip (11) and the distance separating the opposing limiting strips inside one segment (10) of the identification area (7), is comprised between 0,01 and 1, whereby the thickness of the limiting strip (11) is comprised between 0,1 and 1 micrometers. In the cross-section, the limiting strip (11) defining the segments (10) of the identification area (7) represents a geometrical figure comprised between the lines of a secondary order.