Information medium with printed identificaiton information and anti-forgery means

Abstract

The invention relates to the securing of information media so as to prevent any alteration or modification of the identification information and the fraudulent reuse of the media. The identification document according to the invention comprises personalisation information placed on at least one of its main sides, and invisible anti-forgery means placed on at least part of the said side and designed to undergo a change in appearance in the event of an attempt to do additional personalisation. The anti-forgery means are formed by subdividing each pixel into a matrix of N dots, the said N dots having each a different colour density in order to obtain an average colour density of the said matrix that is equivalent to the colour density predetermined for the corresponding pixel, at least some of the said N dots of the matrix being pre-sensitised so that their colour darkens at a variable speed in the event of additional personalisation, as compared to the other non pre-sensitised dots

Dependencies are inferred from the claim text.