APARATO PARA DETECTAR LA PRESENCIA DE DEFECTOS EN UN ARTICU-LO DE MATERIAL TRANSLUCIDO

摘要

This invention concerns an apparatus for detecting the presence of faults in a translucent container of the kind comprising a scanning zone in which a translucent container is rotated while being repeatedly scanned by a spot beam of light in a direction parallel to the axis of rotation of the container, a light collection apparatus being arranged to receive light from the beam after passing through the container. The light collection apparatus comprises a rectangular matrix of photosensitive devices disposed behind a light-diffusing screen upon whose front surface the light from the scanning beam falls after passing through the container. A rectangular grid of thin white walls is sandwiched between the screen and the photosensitive devices so as to define a plurality of boxes with a respective device being located at the rear of each box. The grid thus effectively divides the screen into a large number of elemental areas and provides that each device receives light substantially only from a respective elemental area of the screen. This invention permits the detection of certain nonocclusive refraction faults in the translucent container by selective examination of the device outputs, as well as the detection of occlusive faults by measurement of the total light falling on the screen.