Design Of A Panoramic Annular Lens Based On Free-form Surfaces

Panoramic annular lens imaging system is becoming increasing popular for its prominent features, such as large field of view, small size. Traditional panoramic band imaging system can’t supervise field of view below sea level, since its field of view approximates360°,60°and concentrates above sea level. Moreover, the size of the system can’t be minimized, since the size of its PAL parts is constrained by the requirement to realize multiple reflection within PAL.In this paper, we introduce free form surface with wide degree of freedom into PAL system, which satisfies all severe requirements, such as small size, large field of view.We first discusses the design principle of optical band imaging of wide field of view under visible light and our two types of optical band imaging system with spherical PAL mirrors and free form PAL mirrors. With flat cylindrical imaging principle, spherical mirrors reduce distortion in band view and improve the efficiency of CCD by introducing positive distortion into ultra-hemispherical imaging. Besides, i n terms of the long wave infrared wavelengths, we complete a set of a panoramic long-wave infrared athermal system through design, simulation, plot as well as fabrication. The panoramic band imaging system realize hemispherical imaging with horizontal field of view of360°nd vertical field of view which ranges from0°to60°.Based on theory of mixture of refraction and diffraction and free surface design technology, we realize athermalization and small size as well as light weight.