Design Of Infrared Optical System For Target Seeker

In recent years, with the rapid development and progress of infrared technology, infrared imaging system, which is widely used in military and civilian areas, has become the research focus in every country. As the main components of the infrared imaging system, infrared optical system is used to collecting the infrared radiation imaged in the photosensitive face of infrared detector from the target and background. And this can help the infrared imaging system to search, identificate and capture the target effectively. It has important significance for improving military strength and the living standards of the people in our country.The infrared imaging technology and its development trends have been summarized at home and abroad. The characteristics, performance and design method of the infrared optical system were expounded. Based on these, in order to improve the performance of target seeker, the design of target seeker infrared optical system is realized.According to the design and use of requirement of infrared optical system for target seeker, a catadioptric infrared system is designed, which is based on the cassegrain optical system, in order to eliminate or reduce the influence of temperature on infrared optical system. By analyzing various athermalisation techniques, optical passive athermalisation technique, which could match different materials and reasonable distributing optical power, is used to realize the athermalisation of the infrared optical system in large working temperature range from-40℃to+65℃. Through the error analysis and tolerance allocation, the implementability of the optical system is ensured after assembling adjusting. At the same time, by analyzing image motion and contrasting the compensation mode, the image motion compensation in electronic is used, which improves the image quality of optical system on detector and the resolution capability of detector effectively.Design results show that the design of infrared optical system for target seeker satisfies the requirements of the technical indexes. In the whole visual field, the optical system has a good quality of imaging, MTF is close to the diffraction-limitation at 201p/mm; and in the different visual fields, dispersion spot diameter is less than a pixel size, the structure of the system is also simple. This design ensures the stability of the infrared optical system imaging surface location, meanwhile the properties of the target seeker are improved to some extend.