Apparatus for examining properties of objects

摘要

The invention relates to apparatus for examining magnetic properties of objects, in particular sheet material, such as bank notes ( 20 ). The apparatus comprises a magneto-optic layer ( 10 ) whose optical properties are influenceable by the magnetic properties of the sheet material ( 20 ), a light source ( 11 ) for producing light that is coupled into the magneto-optic layer ( 10 ), and a detector ( 13 ) for detecting light that is transmitted and/or reflected by the magneto-optic layer ( 10 ). For reliable examination of the magnetic properties of sheet material it is provided that the direction of propagation of the coupled-in light extends parallel to a base surface ( 9 ) of the magneto-optic layer ( 10 ). The invention permits the magnetic properties in particular of sheet material with areas emitting very weak magnetic fields to be examined with very high sensitivity and reliability.