Method and array for determining the focal position during imaging of a sample

摘要

A process for determining the focus position when imaging a specimen with a field stop imaged onto the specimen detecting this image using a position-sensitive receiving-device inclined relative to the field stop defining the focus position by means of intensity distribution in the receiving device. The invention also includes arrangements for implementation of the process according to the invention. According to the invention, in a process of the above-mentioned type, imaging of the field stop onto the specimen is at least partially superposed by an optical lattice; the position-sensitive receiving device is used to determine intensity values for the light reflected by the specimen; these intensity values are assigned to positions in the receiving device; position-related contrast values are determined from the position-related intensity values; the position of the contrast focus in the receiving device as equivalent of the current focus position is determined using these contrast values.