提出了一种基于光强信号实时判断的快速定焦方法, 在对样品进行横向扫描的同时, 驱动测量物镜轴向移动, 对前焦探测器和后焦探测器采集到的光强信号进行实时处理, 通过实时判断测量面与样品的位置关系迅速找到焦面位置, 可实现快速、准确的轴向定焦, 极大地提升了定焦速度。理论分析和初步的实验表明, 该方法在一副图像的采集周期内能够实现轴向定焦, 在同等定焦精度条件下, 与清晰度定焦方法相比, 可节省90℅以上的定焦时间。

A fast axial focus identification method based on real-time judgment of light intensity signal is proposed. The samples is scanned by the method in the horizontal plane with the axial movement of measurement objective. The method can real-timely observes and disposes the optical intensity signal collected by the detector before the focus and the detector behind the focus. The focal plane is found through judging the positional relation of measurement surface and sample of the real-time image. It can realize the fast and accurate axial focus identification, and improves the identification speed of the focus significantly. The theoretical analysis and preliminary experiments show that the method can achieve axial focus identification in a scan cycle. In comparison with the definition method of the focus, it saves the process time of more than 90% with the same identification accuracy of the focus.