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Abstract

In a multi-lens infrared objective with wide band chromatic correction, more particularly in the spectral range from 1.4 to 5 .mu.m silicon is employed as a material for lenses with a negative focal length. In this respect the lenses consist of materials, which as regards their dispersion curves are selected from three different material group, of which the first material group comprises materials, whose short wave absorption bands are relatively close to the shortest wavelength to be corrected, the second group comprises materials, whose long wave absorption bands are closer to the spectral range to be corrected than the short wave ones and the third group comprises materials, whose relative absorption band positions are between the materials of the first and second groups.

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First Claim