变焦结构光成像系统的光学设计

为了实现快速低成本改变光学系统焦距，设计了基于液体透镜的变焦结构光三维成像镜头和微透镜阵列。系统采用7片球面玻璃镜片和1片液体透镜结构, F#为3.2，全视场大小为10 mm，总长180 mm，焦距变化范围54 mm~61 mm。结果表明:该系统能实现投影距离227 mm~256 mm调节，调焦过程中目标表面清晰，细节分辨率高，系统在整个变焦区域内，在40 lp/mm时，全视场MTF优于0.2，系统场曲小于0.2，畸变小于0.2%。柱面微透镜阵列整体尺寸为10 mm×10 mm，周期宽度为1 mm，厚度为1 mm。随着投影距离的增长，光学系统成像质量先上升后下降，在237 mm处成像质量最优，随着投影距离的增加，光学系统的放大倍率增大，光学系统整体相对照度不均匀性小于0.2。

Optical design of zoom structured light imaging system

In order to change the focal length of optical system rapidly and at a low cost, we designed the zoom structured light three-dimensional imaging lens and micro-lens array based on liquid lens.The system utilizes the structure of seven spherical glass lenses and one liquid lens, the F# number is 3.2, the full field of view(FOV) is 10 mm, the system total length is 180 mm, and the focal length ranges from 54 mm to 61 mm. The design result shows that, the system can adjust the distance of projection in 227 mm~256 mm; during focusing process the target surface is clear and the resolution ratio has a high quality, while system is within the whole zoom range; at 40 lp/mm, the modulation transfer function(MTF) of full FOV is better than 0.2, the system field curvature is less than 0.2, and the distortion is less than 0.2%.The cylindrical micro-lens array has an overall size of 10 mm×10 mm, a period width of 1 mm and a thickness of 1 mm. With the increase of projection distance, the imaging quality of optical system increases first and then decreases, the imaging quality is optimal at 237 mm; as the projection distance increases, the magnification of the optical system increases; the overall relative illuminance heterogeneity of optical system is less than 0.2.