Optical scanner with soiling detection

摘要

The scanner has a transmitting unit for transmitting a transmission radiation bundle (24), and a front panel (14) arranged in an optical path between a deflection unit (10) and surrounding to be detected. An evaluation unit compares a radiation reflection value of the panel associated to the bundle reflected by a region of increased contamination sensitivity of the panel with a radiation reflection value of the panel associated to the bundle reflected by a region of reduced contamination sensitivity of the panel for estimating degree of contamination of the panel. An independent claim is also included for a method for estimating degree of contamination of a front panel of an optical scanner.