Authenticating articles with up-converting material using two different wavelengths and measuring emission from material

摘要

A advanced product security system comprising at least one up-converting material as a security marking and at least one authenticating equipment, in particular a reader is disclosed, wherein the authenticating equipment comprises at least one first source of electromagnetic radiation of at least one first preselected wavelength and at least one second source of at least one second preselected wavelength which are different from each other; the radiation of the first and of the second wavelength are selected such as to cause the up-converting material upon combined radiation with the first and second wavelength to release an emission spectrum; the electromagnetic emission spectrum of the up-converting material comprises radiation of at least one wavelength which is specific for the return of at least one electron from an energy level to which the electron is raised by the combined radiation of at least the first and the second wavelength.