为了解决现有超广角数字投影镜头存在的缺陷和不足, 并与不同类型和规格数字投影机的超广角投影匹配, 给出了8组9片式超广角数字通用型投影镜头的光学系统设计.镜头焦距为8.76 mm、全视场角达到97°、F数为2.12、后工作距离大于34 mm、最大口径小于96 mm、总长小于200 mm,结构中加入了1个偶次非球面, 较好地校正了轴外像差与畸变.用减少透镜数量和增大相对孔径的办法提高了像面照度；通过增大光阑慧差及减小像方半视场角, 提高了像面相对照度, 其值达97.46%以上.通过合理确定棱镜等效厚度及调整结构布局, 使结构适配光学引擎中棱镜的有效光学厚度为16.5~23 mm.设计的镜头分辨率达120 lp/mm、全视场相对畸变绝对值小于1.5%.结果表明: 该镜头可满足0.55in~ 0.76in 3LCD和1DLP类型的各种数字投影机的使用, 最小投射比可达0.53∶1, 投影画面偏移量最大达到389 mm, 结构简单, 体形小, 成本低, 成像质量好, 可批量化生产.

To solve defects and deficiencies of the existing ultra wide-angle digital projection lens and match the ultra wide-angle projecting from different types and specs of digital projectors, a type of ultra wide-angle digital universal projection lens composed of nine lenses was designed. The focal length is 8.76 mm, the full field of view reaches 97°, F-number is 2.12, BFL is longer than 34 mm, the largest diameter is less than 96 mm and the total optical length is shorter than 200 mm. By setting an effective even aspheric, the off-axial aberrations and distortion are corrected well. By reducing the number of lens and increasing the relative aperture, illumination is improved. By increasing the aperture coma of the system and reducing the FOV of image, relative illumination is improved up to 97.46%. By determining the prim thickness and adjusting the structure and layout, the lens can match prisms of different effective optical thicknesses from 16.5 mm~23 mm in several kinds of digital projector engines. The resolution is 120 lp/mm, and the absolute value of relative distortion is less than 1.5%. The design indicates that the lens can match digital projectors by using 3LCD and 1DLP technologies with the chip sizes from 0.55 in to 0.76 in, minimum projection ratio is up to 0.53∶1 and the largest frame offset reaches 389 mm. Its image quality is excellent with advantages of simple structure, small size, low cost and mass produced.