Medium wave infrared 30 times continuous zooming optical system without rear fixed group

Abstract

The invention relates to a medium wave infrared 30 times continuous zooming optical system without a rear fixed group. The optical system consists of a vari-focal objective lens and a repeater group from an object side to an image side; the vari-focal objective lens consists of a front fixed group lens, a variable time group and a compensating group, the focal powers of the three groups of lenses are distributed into a positive structure, a negative structure and a positive structure in sequence, and the zoom function is realized by the axial movement of the variable time group and the compensating group; the repeater group consists of four lenses, the first lens is a double-convex silicon positive lens, the second lens and the third lens are falcate germanium negative lens facing to the image side, and the fourth lens is a zinc selenide positive lens with the convex surface facing to the image side and is used for repeating an image and stabilizing an image surface in a zooming process. According to the optical system, the double-component mechanical compensation zooming without the rear fixed group and the secondary imaging technology are adopted, the 30 times of large zooming ratio is realized, the focal distance can be changed continuously in a range from 17.5mm to 525mm, the maximum stroke of the zooming group is 106mm, the maximum stroke of the compensating group is 50mm, the total optical length of the system is 350mm, and 100% of cold stop efficiency is realized.

Description

technical field [0001] The invention belongs to the field of optical technology, and in particular relates to a mid-wave infrared 30 times continuous zoom optical system without a rear fixed group applied to a mid-wave cooling infrared focal plane detector. Background technique [0002] The infrared zoom imaging system is divided into two types: continuous zoom and fixed zoom. The continuous zoom infrared optical system is used in the airborne photoelectric reconnaissance system. , adjust to the small field of view for aiming and tracking. The continuity of the image can be maintained during the conversion of the field of view, which is very beneficial for searching and tracking high-speed moving targets. The continuous zoom solves the defect that the two-speed and multi-speed lens loses the fast-moving target during the time interval of the field of view switching in the fixed-speed zoom. Therefore, the continuous zoom optical system is widely used in airborne photoelectri...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problems existing in the domestic existing technology that the zoom ratio is less than 20 times and the travel of the moving group is long; the F-number of the foreign mid-wave infrared 30 times optical system is greater than 4, the limitations of the domestic detector application and the difficulty in purchasing some materials. The invention provides a cooling-type 320×256 yuan 30μm or 640×512 yuan 15μm staring focal plane detector, with a constant F-number of 4 and no rear fixed group mid-wave infrared 30 times continuous zoom optical system

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