Optical system design of long wave infrared zoom lens

As a result of good adaptability, invisibility, anti-jamming ability and recognition ability of camouflaged targets, infrared detection has been applied in infrared navigation, guidance and reconnaissance for military purpose. With the development of infrared technology, it has become more and more important for infrared zoom optical system. In this paper, the design of a zoom lens was described based on the 320×256 staring focal plane array. The operating wavelength range was from 8 to 12 μm, F number was 2.5 and the zoom ratio was 10:1. Moreover, detailed design and image quality were given by CODE V optical design software. When spatial frequency was 16 lp/mm, modulation transfer function (MTF) in the whole focal exceeded 0.35 approaching diffraction limit. The results show that this optical system has large zoom ratio, high resolution, small volume and excellent image quality. Thus, it can be applied in all kinds of opto-electrical detection fields.