Apparatus for detecting the presence of surface irregularities in articles made of transparent material.

摘要

The containers (5) are passed rotatably over a slit (7) having an opaque line (11) situated centrally about the longitudinal axis of the slit. A pair of light sources (15) are positioned beneath the slit and to either side of the opaque line (11) so that, in the absence of surface irregularities, light is refracted at an oblique angle through the container base. A diode-array camera (13) situated vertically above the slit and focussed thereon normally receives no light from the light sources. In the presence of a defect, diffraction of light occurs into the area of view of the camera causing a "defect present" signal to be produced which is processed electronically, enabling the defective container to be rejected.