Patent ID: 7755747

Claim:
Device for checking an authenticity of a forgery-proof marking having a surface with colors which change depending on an angle of observation, comprising: a) several first light sources which emit light in a specified spectral range, wherein the first light sources differ from one another in wavelength of their emission maximum, and wherein the first light sources are installed in a housing so that they irradiate a surface of the marking at a specified first angle when the housing is placed on the surface, b) several second light sources which emit light in a specified spectral range, wherein the second light sources differ from each other in wavelength of their emission maximum, and wherein the second light sources are installed in the housing so that they irradiate the surface at a specified second angle when the housing is placed on top of the surface, which second angle is different from said first angle, c) first means in the housing located at a third angle for measuring intensities of light specularly reflected by the surface of the marking, d) second means in the housing located at a fourth angle for measuring intensities of light specularly reflected from the surface of the marking, and e) means for automatically comparing the measured intensities with stored reference intensities for the respective light sources for at least one specified color.