基准离焦偏差控制技术

Control techniques based on referenced defocus amount

一种新的采用基准离焦信号的针孔调焦方案,用于激光直写的自动对焦子系统。通过在离焦曲线上提取参考离焦信号,建立基准离焦判据,它能容易地区分前离焦或后离焦,有效地克服了原有针孔调焦方案难于根据离焦信号来分辨离焦方向的弱点。借助微处理器和模拟电路实现了这一方案,并因此获得了均匀的1靘线宽的线条。

A new pinhole-focusing scheme using referenced defocus signal is applied to an automatic subsystem for laser direct writing. The referenced defocus criterion is established through extracting reference defocus signal from the defocus curve. The criterion can easily distinguish the front defocus or backward defocus, and effectively overcome the weakness that the original pinhole-focusing scheme is difficult to distinguish defocus direction only by the defocus signal. This scheme is realized by means of microprocessor and analogue circuit, and thus 1-micron uniform lines are obtained.