用于偏振成像系统的20mm~200mm变焦物镜设计

Design of 20mm~200mm zoom objective lens for polarization imaging system

变焦物镜是偏振成像系统的重要组成部分,目前因变焦物镜使用较多非球面而导致价格较为昂贵。为了降低偏振成像系统变焦物镜的加工成本,设计了一款用于偏振成像系统的20 mm~200 mm变焦物镜。采用正组补偿,利用Zemax优化变焦系统,最终系统仅使用7片球面透镜,并达到良好像质,系统调制传递函数(MTF)在120 lp/mm处大于0.3,畸变小于4%,系统凸轮曲线平滑无断点。系统公差分析结果表明,公差范围设置为:镜片表面光圈公差为2,镜片或空气中心厚度公差为±0.02 mm,透镜表面中心倾斜公差为±0.025°,透镜装调公差为±0.025 mm,透镜折射率偏差为0.002,公差设置符合元件加工和系统装调工艺,对降低偏振成像系统成本具有一定的参考价值。

The zoom objective lens is an important part of the polarization imaging system. At present, the zoom objective lens on the market is relatively expensive due to the use of more aspheric surfaces. In order to reduce the processing cost of the polarization imaging system zoom objective lens, a 20 mm~200 mm zoom objective lens for polarization imaging system was designed. By using positive group compensation method and Zemax to optimize the zoom system, the final system used only 7 spherical lenses to achieve good image quality. The modulation transfer function(MTF) is greater than 0.3 at 120 lp/mm, the distortion is less than4%, and the cam curve of the system is smooth without breakpoints. The system tolerance analysis results show that the tolerance range is set as follows: the aperture tolerance of the lens surface is 2, the thickness tolerance of the lens or air center is ±0.02 mm, the inclination tolerance of the lens surface center is ±0.025°,the lens assembly and adjustment tolerance is ± 0.025 mm, and the lens refractive index deviation is 0.002. The tolerance setting conforms to the component processing and system assembly and adjustment process, which has a certain reference value to reduce the cost of polarization imaging system.