Measurement of optical angular deviation for airplane windscreens

A novel measurement method and a full-automatic measurement facility for optical angular deviation of airplane windscreens are presented. Compared with the existing automatic measurement method, this method has clear physical meaning, well defined measurement position and it could achieve more accurate result. The target is a pin-hole instead of a cross or a “L”. A tungsten halogen lamp and a projecting lens are used to generate the collimated light. A CCD detector is used as light spot position sensor to measure the changes of the spot position at the rear focal plane of the imaging lens, and the optical angular deviation can be derived. The measurement facility is traceable to the national angle primary standard with standard optical angular deviation samples. The analysis shows that the measurement uncertainty of the system reaches 7.3″(k=2).