Design Of An Uncooled Infrared Dual Band Continuous Zoom Optical System

Uncooled Infrared Dual Band Continuous Zoom Optical System not only had circadian investigation and the precise characteristics to obtain more comprehensive target information about dual-band fixed focus system, but also had many other advantages with a wide detection range and the search speed, capable of continuous target observation on continuous zoom system. Currently dual-band zoom system generally consisted of two separate systems assembled by mechanical means, the system existed larger, higher equipment costs and higher complexity reconnaissance equipment improvements. Also in the midst of such a system much work environments, and dual-band infrared observation process requires converting the optical path, and the switching process takes a long, slow system response, after switching need to re-search goals, adjust the focus to the target again observation, if at the time of tracking and observing fast moving target, very easy to lose the goal.In response to these problems in such a system, a dual band infrared continuous zoom optical system with the characteristic of uncooled high zoom ratio was designed. The system parameters of the F number was 2. the wavelength was 3-5um/8-12um. the focal length was in the range of 8-160mm. zoom ratio was 20 times. The field range of 2.23°～43.2°. the focal length of the corresponding agreement and compact structure. Based on the theory of infrared zoom, selected the compensation machinery were set to zoom and solved the initial structural parameters of continuous zoom optical system, by introducing the diffraction plane and the even asphere to correct aberration.In the process of continuous zoom, the infrared MWIR/ LWIR dual band were compounded into a same system, and two bands corresponding to the focal length difference were less than the minimum depth of focus system, which reached the aim of synchronous observation and targeted track. The system used an optical passive athermalization method to achieve the athermalization dispose in the temperature range of-40℃-+60℃. The design results showed that the whole field MTF curve was close to the diffraction limit, and infrared MWIR/LWIR band on the energy concentration was greater than 91%/72% respectively within a detector pixel.