Optical height-profile meter for testing authenticity of banknotes, irradiates light beam on reference surface and object area such that plane of reference surface mirrored in object area makes predetermined angle with object plane

摘要

A beam splitter divides the light beam into measurement and reference beams that are respectively irradiated on reference surface (8) and object area, such that the plane of the reference surface mirrored in the object area and the object plane (14) form a predetermined angle (F). An evaluation unit detects interference patterns resulting from superposition of reflected reference beam and backscattered measurement beam. Independent claims are also included for the following: (a) Use of profile meter for recognition and testing of banknotes; (b) Method for optical measurement of surface profile