利用光纤传像束的内窥镜物镜设计

光纤传像束用于内窥镜时，对内窥镜物镜的结构型式和成像质量提出了新的要求。在分析了其基本设计原则后，根据实际需求，选用反远距型物镜作为初始结构，利用Zemax软件优化设计了一个工作波段0.38~0.78 m，焦距0.921 mm，全视场100、相对孔径1/4的内窥镜物镜。镜头总长10.32 mm，满足像方远心要求，在38 lp/mm频率处MTF值在0.85以上，像质优良；同时，在Tracepro软件中建立了所设计物镜与光纤传像束结合后系统的模型，模拟的系统耦合效率约为96%且出射端照度均匀。结果表明:该物镜具有视场大、短焦距、结构合理、耦合效率高、像面照度均匀等特点，满足内窥镜要求。

Design of the objective lens for endoscope with imaging fiber bundle

For the endoscope with imaging fiber bundle, either the configuration or the imaging quality of its objective lens should satisfy some new requirements. Firstly, the fundamental of the objective lens design was analyzed, and the retrofocus objective lens was chosen as an initial structure for this design. Then an objective lens for the fiber-optic endoscope was designed with the software Zemax. The operation wavelength, focal length, FOV(field of view) and relative aperture of the designed lens are 0.38-0.78 m, 0.921 mm, 100 and 1/4 respectively. Its total length is 10.32 mm. It's telecentric in image space. The MTF value of the lens is greater than 0.85 at the spatial frequency of 38 lp/mm. Furthermore, a model of the designed lens combined with the imaging fiber bundle was established in the software Tracepro. The coupling efficiency of the simulated system is about 96% and the illumination of output end is uniform. All the results show that the designed lens has the peculiarity of wide FOV, short focal length, logical configuration, high coupling efficiency and uniformity illumination at image plane. It is suitable for the fiber-optic endoscope.