Research On Design Athermalisation Of TV Seeker Zoom Optical Systerm

Along with the rapid development of scientific technology, high-tech guidedmissile began to appear in the modern battle field, since it has very high hittingaccuracy and long guide distance, especially destructive etc, so it become one of themost important powers in the modern war. Becase TV guidance system has a lot ofadvantages, like high reaction speed, strong anti-interference ability, high reliability,small volume, light weight, low cost etc, so the TV guidance model has been widelyused in all sorts of air-air and air-ground missiles in the world.Firstly, this paper researched the TV seeker’s maximum and minimum workdistance, tracking precision, adaptation to the environment and signal processing ability,and these key technology solutions, and analyzes the function of TV seeker’s each partof optical system such as optical glass, double plane mirror, optical lens and the CCDdetector concretely, through analysis actual application of each part, and select structureof each components separately.Then based on the zoom theory of the mechanical compensation, determine thestructure and the calculation process of the zoom optical system.Analyze the factors thataffect the optical system when the temperature change, and analyze the conditions andthe method to realize the system’s athermalisation. Check the parameters of system toensure the feasibility of the system design.According to the gauss calculation, and get the initial zoom structure parameters ofcompensation group which the focal power is positive, and reference the optical systemstructure of the patent lens that in the Optical Technical Manuals, then use the Code Vsoftware to optimize this optical system and evaluate the image quality, finally theoptical system is that focal length is25to75mm, MTF is more than0.6at56lp/mm,the distortion is less than3.2%, the total length of system is145mm, the image qualityis better, the zoom structure is simple. Then use the optical passive method and edit themacro command in Code V, which include of dn/dt and thermal expansion coefficient ofoptical glass, and then get the excellent image quality by replacing partial materialsproperly, ensure that the temperature in range of-45℃to55℃, the MTF of the zoomoptical system is more than0.48.At last, this paper analyzes the different kinds of tolerances, including the formsand the default value of tolerances. Contrast four analysis methods, and complete thetolerance allocation of the zoom optical system by using the anti-sensitivity mode ofTOR.