PROBE FOR INFRARED OBSERVATION

摘要

PROBLEM TO BE SOLVED: To obtain a probe for infrared observation excellent in chemicals resistance and weather resistance by constituting an optical part existing nearest to an object side in an infrared objective optical system of material principally composed of aluminum oxide.;SOLUTION: The optical part existing nearest to the object side in the infrared objective optical system is constituted of material principally composed of aluminum oxide(Al2O3). For example, it consists of an objective lens constituted of sapphire cover glasses r1 and r2 principally composed of aluminum oxide, negative lenses r3 and r4, positive lenses r5 and r6 and the positive lenses r7 and r8 all of which is made of zinc sulphide. In the case of making either end face of the lens nearly plane, an expression: ϕL/2≥ϕF/2+D×tanθ is satisfied when the inside diameter of a spacing tube provided between the lens and an infrared transmissive fiber bundle is ϕL. Provided that ϕF is the effective diameter of the fiber bundle, D is a distance between the lens and the fiber bundle and θ is the angular aperture of the fiber bundle.;COPYRIGHT: (C)2000,JPO