DEVICES AND METHODS FOR INVESTIGATING THE MAGNETIC PROPERTIES OF OBJECTS

摘要

The invention relates to devices and corresponding method for investigating the magnetic properties of objects, in particular sheet material, such as for example banknotes (20). The devices comprise a magneto-optical layer (10), the optical properties of which may be influenced by the magnetic properties of the object under test, a light source (11), for the generation of light, which may be coupled with the magneto-optical layer (10) and a detector (13) for the detection of light transmitted and/or reflected from the magneto-optical layer (10). Reliable investigation of the magnetic properties of sheet material can be achieved, whereby the dispersion direction of the coupled light runs parallel to a base surface (9) on the magneto-optical layer (10). By means of the above invention, the magnetic properties of objects, in particular magnetic regions of sheet material from which only a very weak magnetic field emanates can be investigated with high sensitivity and reliability.