An uncooled mid- and long-wavelength broadband confocal infrared optical system

Abstract

The invention belongs to an infrared optical system, and in particular discloses an uncooled medium and long-wavelength broadband optical system, which comprises an objective lens group, an imaging lens group and an optical filter which are arranged in sequence from the object surface to the focal plane and fixedly connected; The objective lens group, the imaging lens group, and the central axis of the filter are coaxial. Both the objective lens group and the imaging lens group have positive refractive power. The objective lens group is a four-separation lens structure. The lens, the first negative lens, the second positive lens and the second negative lens, the imaging lens group is a single lens structure, and is composed of a third positive lens. The resulting aberrations are well corrected, enabling confocal imaging in the mid- and long-wave infrared wide-band range, and a relative aperture of not less than F number of 1.1, and realizing athermalization of the optical system, which is easy to manufacture and has high imaging quality. , Good stability.

Description

technical field [0001] The invention belongs to an infrared optical system, in particular to an uncooled medium-long-wavelength broadband optical system, which has the function of passive heat dissipation. Background technique [0002] Vanadium oxide or amorphous silicon type uncooled infrared focal plane detectors are thermocouple type detectors, which can respond to thermal infrared signals in a wide band range, and are widely used in industrial monitoring, security monitoring and other fields. Moreover, with the continuous improvement of the sensitivity of this type of uncooled focal plane detector, it can detect harmful or tracer gases such as VOCs (volatile organic compounds), sulfur hexafluoride, etc., replacing the previous expensive refrigeration type. Infrared detectors make it possible to reduce the cost of infrared imaging equipment using such detectors. However, due to the working principle of this type of detector, the sensitivity of uncooled infrared detectors...

AI Technical Summary

Problems solved by technology

[0006] Chinese patent CN 105319669B discloses a dual-band infrared optical system, the optical structure shares six lenses, and the working bands are 3.7μm-4.8μm and 8μm-12μm medium and long-wave dual-band; The uncooled medium and long-wave dual-band infrared optical system has a focal length of 1.72 inches, an F number of 1.25, and a half field of view of 22.5°, but its working bands are 3 μm to 5 μm and 8 μm to 12 μm, and none of them can achieve 3 μm to 14 μm Wide working band, and does not have athermalization function

[0007] In addition, the Chinese patent CN 104516110A provides a split-focus surface design for the medium and long-wave infrared dual-band, while the Chinese patent CN 110398828A provides a split-aperture and split-focus surface design, which cannot realize the wide-band range of the medium and long wavelengths. confocal imaging

[0008] However, Chinese patents CN 1042979088, CN 105317488, CN 202794679U, and U.S. patent US6423969 are all designed for cooling medium and long-wave infrared detectors. The relative aperture is small, and it is difficult to meet the requirements of uncooled broadband detectors.

Although the US patent US 4871219 is designed for uncooled detectors, it also has the problem of relatively small aperture

[0009] In 2013, the document "Optical design of common aperture, common focal plane, multispectral optics for military applications" published in Optical Engineering, Vol. The focal length of the system is 50mm, and the F number is 1.9. Although the whole system has no central obstruction and is compact, it still has a larger volume than the transmissive system, and the three reflective surfaces are all Zernike surfaces, which also increases the processing of the three-mirror system. difficulty of fitting

Published in the 17th volume of Journal of Optics in 2014, the document entitled "Design of a low F-number freeform off-axis three-mirror system with rectangular field-of-view" discloses another three-mirror structure, although it realizes Larger relative pore size, but still has implementation difficulties

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