针对微结构的偏转角度测试需求, 设计并搭建了一套基于显微光杠杆技术的角度测量系统。该系统将光杠杆光路与无限共轭显微光路相结合, 所得聚焦光斑直径小于10μm; 采用电流模式电路处理四象限探测器输出信号, 系统理论带宽超过5MHz; 系统对微结构的转角测量分辨力和理论量程分别可达1.2″和±4°。利用该系统测量了原子力显微镜微悬臂梁探针在步进载荷下的偏转情况, 测量结果与铁摩辛柯梁理论计算一致, 验证了系统的可靠性。

A microscope system for the deflection angle measurement of microstructures is presented. The microscope consists of an infinite conjugate imaging system and an integrated optical lever. The laser beam of the optical lever is focused by the infinite objective to a size less than 10μm. A current-mode circuit is designed for signal processing for the optical lever, and 5 MHz in bandwidth is achieved. The measurement range and resolution of the system are ±4° and 1.2″, respectively. As a test, the system is used to measure the deflection angles at the free end of a cantilever probe of atomic force microscope under step load. The measurement results are consistent well with the calculation by using Timoshenko beam theory.