采用“非相似”成像原理, 利用Zemax光学软件设计了一款适用于160 cm(0.63英寸)3LCD数字投影机的球幕投影数字鱼眼镜头。镜头结构是一种反远距型光学结构, 由5组6片球面透镜组成, 具有结构简单、易加工等特点。镜头全视场角为180°, 焦距为3.28 mm, 相对孔径为1/1.9, 后工作距离为35.8 mm, 光学总长为196 mm。镜头具有较高的成像质量, 在50 lp/mm处, 各个视场的MTF值均大于0.4, 最大垂轴色差为4.5 μm, 全视场的F-theta畸变绝对值小于3%, 最大视场的像面相对照度达到96.27%。

A digital fish-eye lens for dome-screen projector applied to 0.63 inch 3-liquid crystal on silicon(3LCD) projectors was designed in Zemax based on the principle of non-similarity. The lens is composed of 6 spherical lenses, and has the retrofocus optical structure. Its image quality is excellent with the advantages of simple structure, low cost and easy process. The full field of view (FOV) of the lens is 180°, the effective focal length (EFL) is 3.28 mm, the relative aperture is 1/1.9, the back focus length( BFL) is 35.8 mm and the length of optical system is 196 mm. Its modulation transfer function (MTF) in all field is higher than 0.4 at 50 lp/mm. The lateral color is less than 4.5 μm. The absolute value of F-Theta distortion of the full of view is less than 3%. The relative illumination of the image in the maximum of view is 96.27%.