Design Of Ultrathin Optical Imaging System Using Annular Aperture

With the enhancement of requirement for camera, ultrathin miniature camera will become one of most important parts in the future market. Although miniature camera lenses are very common, their resolution and light collection power can not be compared with conventional large ones. The thickness of a camera is mainly constrained by the configuration of its lens. In order to reduce its volume and thickness meanwhile to maintain as good imaging quality as a conventional camera, the key problem to be solved is to improve its lens design. How to make camera lens thinner and smaller is the primary task. Reduction of the bulk and weight of visible imaging systems is important for applications where bulky conventional imaging systems are unsuitable, as in surveillance cameras for miniaturized unmanned aerial vehicles and portable infrared telescopes.Here the principle and design method about a special kind of ultrathin optical imaging system with annular aperture is introduced. It is an extension of flat plate lenses and can keep high light collection and resolution and reduce its thickness and weight at the same time. This kind of lenses has the advantages of both the compactness of miniature systems and the high imaging performance of large ones. The optimized result and its performance evaluation of an eight-reflection folded lens among this kind of lenses are reported.Ultrathin optical imaging system using annular aperture can also considered as a special kind of sparse aperture system. It can reduce the bulk and mass when used in space remote and astronomy. In fourth chapter, this kind of application is explored and investigated. Three telescopic objectives with different fold times are designed. They have different number of high-order aspheric mirrors. Their performance evaluation and tolerance analysis are given and compared. This system is compact and could be expected to be used as a micro satellite payload with high resolution.