Purity testing system for determining impurities in hollow glassware

The invention relates to a purity testing system for determining impurities in hollow glassware, which system has mechanisms for moving the hollow glassware (7), furthermore a laser (1) as light source for transilluminating the hollow glassware (7), a photodetector (16) for sensing the light beam leaving the hollow glassware (7), and an electronic unit for analysing the output signals from the photodetector (16), and there is located between the laser (1) and hollow glassware (7) a beam deflector (3) to ensure the scanning movement of the laser beam, furthermore provision is made between the hollow glassware (7) and the photodetector (16) for an optical diffusor element (15) in order to disperse the light beams which have passed through in directions deviating from its original direction. The essence of the invention is that the optical diffusor element (15) is connected directly to the photodetector (16), furthermore the optical diffusor element (15) is configured as a directional filter element. The dimensions of the sensor surfaces and their distance from the diffusor element (15) are selected in such a way that the spatial angle of the light beams (17) which are sensed is smaller than 10 degrees, advantageously smaller than 5 degrees, while the directional angle (20) of the spatial angle (19) is smaller than 30 degrees, advantageously smaller than 20 degrees.