MATERIAL PROBLEM IN ATHERMALIZATION OF OPTICAL-SYSTEMS

Three thermal effects-variation of image location, variation of focal length and longitudinal chromatism-are described in the form of formul as, which include surface distributions proportional to the thermal co nstants. Principles for the optical system athermalization by means of optical (passive) compensation and thermooptical (active) compensatio n are given. The problem of proper selection of thermal material const ants and mechanical constants of lenses and mounts is discussed. The c ondition for achromatization in the form of the formula including mate rial distributions and the principle of material selection is given. ( C) 1997 Society of Photo-Optical Instrumentation Engineers.