目前电子内窥镜仅能观察前方视场, 为了消除后方视野盲区给病人带来的误损伤, 设计了一个可以同时观察前方和后方视场的电子内窥镜。第一片透镜采用类“双胶合”透镜设计的方法, 并在透镜的前表面添加环形反射膜来满足前置物镜透射和反射的需求。系统采用球面设计, 以降低成本。运用Zemax软件对系统进行优化, 并配以1/10 in(1 in=2.54 cm)电荷耦合器件(CCD)接收成像。设计结果表明, 该系统的径向尺寸为5.5 mm, 满足内窥镜对小尺寸的要求, 轴上和轴外像面照度均匀, 各视场在100 lp/mm处的光学传递函数(MTF)值在0.75以上, 接近衍射极限, 满足分辨率的要求。

The electronic endoscope can only observe the front field of view. In order to eliminate patients′ injury from the blind area in the rear, an electronic endoscope which can observe both the front and rear field of view at the same time is designed. The first lens is designed according to the method similar to double agglutination. Circular reflective film is added to the front surface of the lens to meet the need of transmission and reflection. The endoscope chooses spherical design to reduce the cost. The system is optimized by Zemax stimulation, and equipped with 1/10 in (1 in=2.54 cm) charge coupled device (CCD) to receive image. The results show that the radial dimension of the system is 5.5 mm, which meets the requirement of small size. It also has uniform illumination at image plane on axis and off-axis. The modulation transfer function (MTF) value of this system is greater than 0.75 at the spatial frequency of 100 lp/mm at the whole view, which is close to the diffraction limit and meets the resolution requirement.