AUTO-FOCUS SYSTEM, DISTANCE MEASURING SYSTEM, AUTO-FOCUS METHOD, AND AUTO-FOCUS SYSTEM CALIBRATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a distance measuring system for auto-focusing a camera of an inspection system for inspecting a planar surface that is patterned.SOLUTION: The system includes a pattern generator, an image sensor, an optical element and a processor. The pattern generator projects a spatially random pattern toward the planar surface at an oblique angle. The optical element forms an image of a reflected pattern on the image sensor, and the image sensor captures the image of the spatially random pattern reflected off the planar surface. The processor processes the image of the spatially random pattern and provides auto-focus information.SELECTED DRAWING: Figure 1