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In the field of science and technology as well as the military , high-performance missile is to ensure that the key tasks of modern warfare , but the entire missile seeker 's eyes , you can complete the autonomy of the target search , identification and tracking , and gives guidance desired signal. The optical system of the reign scaler forefront target infrared radiation received , and the role of the seeker distance , track search capabilities have a certain influence . Therefore, the optical imaging quality is good or bad for the entire seeker has a crucial role . Based on the technical requirements of the seeker , based on the optical design software ZEMAX, an infrared seeker designed optical system , the system uses Cassegrain optical system plus a correction group can wave 3.7μm-4.8μm, longwave 8μm-12μm dual band simultaneous imaging , with a ± 2 ° wide field of view , and in the -40 ° -50 ° Athermalized meet requirements . Cassegrain system using ellipsoidal primary mirror , the secondary mirror is hyperboloid , compensation lens group with three corrective lenses , the design results: When the cutoff frequency of 11mm/lp time , MTF curve is greater than 0.7 , the whole field of view is 0.6 and the four -field wave aberrations were less than 0.25λ, to meet the design requirements . Taking into account the alignment process , and the production cost and other factors , to further improve the structure of the system . Particularly large fairing of the aberration correction lens surface and the introduction of non- spherical , by the use of non- spherical , which greatly improves the image quality. Cassegrain secondary system of primary and secondary mirrors are spherical mirror instead of conical surfaces , greatly reducing the processing alignment difficult. Correcting lens is reduced to two from the three , not only saves costs and reduce the weight of the system , but also the structure of the system more compact. Meet seeker optical system requirements for use in confined spaces . The improved system design results as follows: When the cutoff frequency is 11mm/lp , four fields were greater than the MTF curve equal to 0.7 , close to the diffraction limit. The RMS radius of each field are : 63.416 um, 65.228μm, 62.249μm, 39.566μm. Waves differ by less than 0.038λ, meet the image quality and design requirements .
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