Optical transmission or reflection characteristics measuring system

摘要

The measuring system has a beam from a light source (20) directed onto the sample (22), the resulting optical reflection or transmission signal provided by a detector (24) in the path of the reflected or transmitted beam after reflection by a retro-reflector (23). In the case of a reflected measuring beam, the retro-reflector lies at a different angle to the required position of the sample to the angle of incidence of the light from the source with the required sample position.