CONTROLLED FLUID FLOW FOR CLEANING AN OPTICAL ELEMENT

摘要

A fluid (105) is directed toward a surface (422) of an optical element (420) based on a first flow pattern, the surface of the optical element including debris and the fluid directed based on the first flow pattern moving at least some of the debris to a first stagnation region (425) at the surface of the optical element; and the fluid is directed toward the optical element based on a second flow pattern, the fluid directed based on the second flow pattern moving at least some of the debris to a second stagnation region on the surface of the optical element, the second stagnation region and the first stagnation region being different locations at the surface of the optical element.