Opto-electronic monitor detecting web holes - has photo-electric transducers receiving deflected and focussed laser beams and supplying evaluating circuit

摘要

The opto-electronic monitor is partic. applicable as a scanner for holes in webs. A sender section includes a laser that produces a light barrier extending over the region to be monitored. A row of inclined reflectors deflects a scanning light beam having an angle of incidence corresp. to the direction of the row about an angle of 90 deg. within the area of the light barrier. A row of lenses is assigned to the reflectors on a one-to-one basis. Photo-electric transducers behind the lenses form a receiving section. Light arriving from the barrier and incident on the lenses is concentrated on the transducers the output signals of which are fed to an electronic evaluating circuit. The relative mounting of the reflectors is such that the deflected partial beam zones overlap in the direction of the row.