Cathode for image intensifier tube having reduced veiling glare

摘要

An image intensifier tube has a faceplate formed of optical material. The outer surface of the faceplate has light receiving and light transmitting surfaces and a layer of a reduced metal oxide material for reducing stray light which is transmitted into the faceplate and reflected off of internal surfaces thereof. The layer has a blackened appearance and is formed by reducing the metal oxide of the faceplate material with hydrogen at a predetermined pressure and temperature to cause the blackening to reach a depth sufficient to reduce transmission of stray light therethrough.