用于光具座自动测量焦距的变焦光学系统设计

为了提高光具座自动测焦距时的测量精度，设计一套连续变焦光学系统。该系统包括自准直组件和变焦组件两部分，可以调节CCD靶面上接收到的图像大小，得到最佳测量结果。根据设计指标要求，在控制系统总长的基础上进行初始结构选择和像质优化。设计完成后的自准直组件焦距200 mm，变焦组件焦距200 mm~20 mm，对接后的变焦系统可实现图像大小1~10连续调节。模拟实验表明:变焦系统像质良好，MTF曲线接近衍射极限，弥散斑小于CCD像元大小，可以满足实际检测需求。

Design of zoom system for automatic focal length measurement on optical bench

In order to improve the accuracy of automatic focal length measurement on the optical bench, a continuous zoom optical system was designed. The system is composed of self collimation component and zoom component, and can adjust the size of image on CCD target surface till the best measurement is got. According to the technical requirements of the zoom system and based on the total control, the initial structure selection and image quality optimization were done. After the completion of the design,the focal length of self collimation component is 200 mm,the zoom component is 200 mm～20 mm and the zoom system after docking can realize the image size of 1～10 of continuous adjustment. Simulation results show that the zoom system shows good image quality,the modulation transfer function (MTF) curve is close to the diffraction limit, and the dispersion spot is less than the size of CCD pixel. The above implies that actual testing requirements can be met.