Night vision device having a chalcogenide glass lens, infrared imaging system or thermal imaging system, doublet lens, infrared lens system

摘要

The invention relates to chalcogenide glass compositions for use in a lens system to balance thermal effects and chromatic effects and thereby provide an achromatic and athermal optical element that efficiently maintains achromatic performance across a broad temperature range. The glass composition is based on sulfur compounded with germanium, arsenic and/or gallium, and may further comprise halides of, for example, silver, zinc, or alkali metals. Alternatively, is based on selenium compounded with gallium, and preferably germanium, and contains chlorides and/or bromides of, for example, zinc, lead or alkali metals.