基于二象限探测器的离焦探测

为同时获取离焦方向和离焦量,二象限探测器是最简探测器。在由二象限探测器构成的离焦探测系统中,当光斑移动方向与探测器分界线有一固定或变动夹角时,将引起离焦曲线变化或不稳定。此外,实际的探测器所具有的死区也会影响离焦曲线,同时还限制离焦动态范围。由除法构建的离焦算法,已被用于激光直写中离焦探测部分的设计。

Defocusing detection based on dual-quadrant detector

Dual-quadrant detector is the most convenient detection tool in getting both defocus direction and amount at the same time. In defocusing detection system based on dual-quadrant detector, the defocusing curve would be affected if the light spot moves but not along the direction of the boundary between two quadrants. Furthermore, the dead region of actual detector will influence defocusing curve and shrinks its dynamic range. Defocusing algorithm based on division operation has been applied in design of defocusing detection in laser direct writer.