Device and method for determining the focal position

摘要

Laser light (52) from a laser light source (14) is collimated by a collimating lens (16) and reflected by semi-reflecting surfaces (20,22) that are angled relative to the z-axis (11). Light reflected from the surface (20) forms a light field (54), light reflected from the surface (22) forms the light field (56) and light reflected from both surfaces forms the light field (58). A CMOS sensor (24) registers part of an interference sample within an overlapping area (57) of the light fields (54,56). Independent claims are also included for: (1) an optical imaging system; and (2) a laser scanner.