Large-relative-aperture long-focal length non-cooled infrared athermalization optical system

Abstract

A large-relative-aperture long-focal length non-cooled infrared athermalization optical system is arranged in front of the focal plane in the light spreading direction, and is composed of a main reflector, a secondary reflector, a first positive crescent lens, a second positive crescent lens, a reflection/diffraction mixed lens, a movable lens and a second negative crescent lens which are coaxially arranged in parallel. The system adopts a cassette system to increase the optical path by multiple reflections of light, thereby realizing the long coking of the optical system, wherein F<#> is 1; the focal length is 500mm; the center block is smaller or equal to 0.3; and the optical total length and focal length ratio is smaller than or equal to 0.64. Through the secondary imaging, the impact of stray light on the image quality of the system can be effectively inhibited. With the utilization of characteristics of negative dispersion and negative thermal expansion coefficient of the diffractive element and the reasonable distribution of the focal power of the reflection/diffraction mixed lens, the defocusing amount caused by the infrared optical system due to the temperature change is reduced, and combined with the mechanical active athermalization, the image plane defocusing compensation of the system in the temperature range of from -40 DEG C to +60 DEG C is achieved.

Description

technical field [0001] The invention belongs to the technical field of uncooled infrared imaging, and in particular relates to an uncooled infrared athermalization optical system with a large relative aperture and long focal length. Background technique [0002] With the development and progress of technology, the pixel size of the uncooled infrared system is continuously reduced, the sensitivity is continuously improved, and its price is gradually reduced. In addition, because it does not require a refrigerator, the system has high reliability and can be miniaturized, it is more and more widely used in security monitoring, automotive and other fields. [0003] However, the uncooled infrared system has low temperature resolution and poor detection ability. In order to improve the temperature resolution and target detection ability of the system, the infrared optical system is required to have a large relative aperture and a long focal length. [0004] The existing uncooled ...

AI Technical Summary

Problems solved by technology

In practical applications, changes in temperature will cause changes in the curvature, thickness, and refractive index of infrared optical components, resulting in defocusing of the system, making the imaging quality of the infrared optical system degrade, which has a particularly serious impact on the imaging quality of large-aperture systems, and even cannot clear imaging

In addition, the system adopts one-time imaging design, which cannot effectively suppress the influence of stray light on the imaging of the optical system

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