Double-view-field/double-color infrared thermal difference eliminating optical system based on harmonic diffractive optical element

Abstract

The invention relates to a double-view-field / double-color infrared thermal difference eliminating optical system based on a harmonic diffractive optical element, in particular to a thermal difference eliminating optical system with cold diaphragm efficiency being approximately 100 percent, belonging to the field of infrared thermal imaging. The working band of the system is 4.4-5.4mum / 7.8-8.8mum, the focal length of the system is 183mm / 61mm, and the operating temperature of the system is minus 40 DEG C to 60 DEG C. The F values of optical systems with a wide view field and a narrow view field are identical (2.68), one double-color infrared focal plane detector is shared, and the cold diaphragm efficiency is approximately 100 percent. The effect of eliminating thermal difference is realized via a micro movement zooming lens group, so that MWIR (medium wave infrared rays) and LWIR (long wave infrared rays) have the same focus for imaging within respective working scopes. The structure comprises an object lens group, a zooming lens group, a relay lens group, double-color infrared detector window glass, a diaphragm and a double-color infrared detector. The system comprises one harmonic diffraction plane and three even non-spherical surfaces, and only three commonly used infrared materials are used as optical materials, i.e. germanium, zinc selenide and calcium fluoride.

Description

technical field [0001] The invention relates to a dual-field / two-color infrared athermalization optical system based on a harmonic diffractive optical element, in particular to an athermal imaging optical system with a cold diaphragm efficiency approximately 100%. It belongs to the field of infrared thermal imaging. Background technique [0002] Harmonic diffractive optical element is also called multi-level diffractive optical element, which is characterized in that the optical path difference between adjacent annular zones is the design wavelength λ 0 Integer P times of , the same optical power can be obtained at a series of separated wavelengths, which can be applied to the design of two-color infrared optical systems. The dispersion performance of the harmonic diffractive optical element is between the refractive element and the ordinary diffractive optical element. Its superior characteristics of correcting chromatic aberration can indirectly play a role in simplifying...

AI Technical Summary

Problems solved by technology

Due to various difficulties, most of the existing domestic optical systems stay in the dual-field-of-view dual-band imaging stage that has not been cooled

At present, the most advanced optical system among the infrared thermal imaging optical systems reported abroad is the dual-field-of-view dual-band switching imaging optical system in France. And this system has already considered the heat dissipation difference

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