设计出以可编程控制器、伺服电机放大器、伺服电机和编码器为主要部件的可编程机械斩光器，并将其与多光镊系统相耦合，构建了胶体微粒间相互作用势测量系统。利用该系统测量聚苯乙烯球悬浮液中两个小球之间的静电相互作用势，其结果与胶体稳定理论符合，验证了系统的可靠性。该斩光器具有良好的易用性、兼容性和可移植性。并且该系统能在可控的物理化学条件下从粒子层次直接测量胶体粒子间不同类型的相互作用势，为深入研究胶体的微观机制提供了一种有效的测量手段和技术平台。

A mechanical chopper is designed based on the programmable logic controller, servo motor amplifier, servo motor and encoder. The interaction potential measurement system is constructed by the mechanical chopper and dual optical tweezers. The characteristic of the system such as the design of the chopper, the switching time of the blinking optical tweezers, the tuning range, the origin position return feature, the compatibility and the usability of the system are discussed. The system is used to measure the interaction potential of a pair polystyrene spheres. The result is consistent with the Darjaguin-Landau-Verwey-Overbeek theory, which demonstrates the reliability of the apparatus. In addition, the apparatus provides an effective technique for measuring the interaction potential between two micro colloidal particles.