Object protection device for forgery prevention or authentication e.g. for banknote, emits visible light whose intensity or spectral content varies with time

摘要

The device includes an emitter (10) that is integrated into the object to be protected, and autonomously emits light in the visible spectrum, at least when there is ambient light available for observing the object. The intensity and/or spectral content of the light vary with time. The temporal variation is selected or set so that it is perceivable by human vision. Light may be emitted using a LC device and a LED, with a piezoelectric or electrostrictive actuator moving the light emitting device to produce the characteristic variation. Independent claims are included for an object, in particular, a means of payment; and for a method of protecting an object.