Security device for the identification or authentication of goods and method for securing goods using such a security device

摘要

A security device for the identification or authentication of goods is described. It comprises a stochastic pattern comprising structures having an average lateral structure size d and arranged such that an image of at least a part of the security device, when treated through 2D Fourier transformation and calculation of a corresponding Power Spectrum Density, may lead to a peak, in a spatial-frequency domain, having a position in this domain correlated to d and a size distribution value w which, when inverted, is correlated to a size distribution of the structures. The value w according to the invention is smaller than 2/d, so that when directing a coherent light beam on at least part of the structures a ring-shaped scattering speckle pattern is formed, on the basis of which d and w may be calculated to implement identification or authentication of the device.