大口径透镜模块的颗粒污染物吹扫机理及验证

Flushing mechanism and verification of particulate contaminant from large-aperture lens module

为了解决终端光学组件中的大口径透镜污染损伤问题,实现透镜表面的在线洁净,提出了一种新的污染物去除方式,利用风刀技术实现颗粒污染物的在线去除。通过有限元方法模拟了透镜表面颗粒污染物吹扫过程,研究了在层流风和风刀的共同作用下透镜模块中的流场分布状态和颗粒运动轨迹。研究结果表明:当层流风速为0.3 m/s时,透镜模块内部能够形成稳定流场;当风刀距离透镜上表面78.73 mm时,能够有效降低风刀气流在透镜表面的应力集中;当风刀风速为30 m/s时,风刀气流能够有效隔离出射速度小于50 m/s和颗粒直径小于75μm的二氧化硅颗粒。通过实验验证了风刀在透镜表面的安装位置和气流在透镜表面的速度分布特征,机械构件比光学元件溅射的颗粒污染物更难去除。最终获得风刀在透镜表面颗粒污染物吹扫和隔离的有效技术参数,为大口径透镜模块的在线颗粒污染物去除提供新方法。

In order to solve the problem of contamination damage of large-aperture lens in final optical assembles and realize the online cleaning of lens surface,a new method of contaminant removal was proposed,which used the air knife technology to realize the online removal of particle contaminants.The flushing process of particles on the lens surface was simulated by finite element method.The flow field distribution and particle trajectory in the lens module were studied under laminar air and air knife.The results show that when the laminar wind velocity is 0.3 m/s,a stable flow field can be formed inside the lens module.When the distance between the air knife and the upper surface of the lens is 78.73 mm,the stress concentration of the air knife on the lens surface can be effectively reduced.At the same time,when the air knife has a wind speed of 30 m/s,the air knife can effectively isolate silica particles with an exit velocity less than 50 m/s and a particle diameter less than 75μm.The installation position of the air knife on the lens surface and the distribution characteristics of the air flow velocity on the lens surface are verified by experiments.The sputtering particle contaminants of mechanical components are more difficult to remove than those of optical elements.Finally,the effective technical parameters of the air knife on the surface of the lens are obtained,which provides a new method for the on-line removal of particle contaminants of the large-aperture lens module.