Optical imager for the 3-5 micron spectral band

摘要

An optical imager for use in the 3-5 micron spectral band. The imager comprises a large aperture positively-powered first objective lens made of a first material for collecting collimated light, and a slightly negatively-powered second objective lens made of a second material spaced behind the first objective lens to provide a color-corrected intermediate focal plane for the collected light. The imager further includes a relay group of three lenses disposed behind the second objective lens for re-imaging the intermediate focal plane.