OPTICAL INSTRUMENT

摘要

An optical measurement instrument for monitoring characteristics of a liquid such as water. An optical beam is generated and directed into the thread (7) of liquid such that the beam is guided along the length of the thread by total internal reflection. Components of the beam that are affected by variations in characteristics of the liquid defined by the thread are detected. These components may be derived from the thread by causing the thread to impinge against a window (8) behind which the detector (9) is located or by detecting back-scattered components of the beam. Relatively long interaction lengths between the beam and the liquid can be achieved.