Autofocus method and autofocus device

摘要

The invention is based on an autofocus method in which light from a light source (12) is focused at a measurement light focus (52) in a sample (6) and is reflected from there and the reflected light is guided through an optical system (22) in two light paths (48, 50) onto at least two detector elements (72, 74). In order to achieve fast and accurate automatic focusing on the sample, it is proposed that the measurement light focus (52) is moved in layers of the sample (6) which reflect light to different extents, and the detector elements (72, 74) are arranged in such a way that, in this case, profiles of a radiation property registered by the detector elements (72, 74) are different and a focus position is set in a manner dependent on the profiles.

主权项

1. An autofocus method, in which light from a light source is focused at a measurement light focus in a sample and is reflected from there and the reflected light is guided through an optical system in two light paths onto at least two detector elements,
characterized in that the measurement light focus is moved in layers of the sample which reflect light to different extents and the reflected light is guided through at least one aperture, which is arranged outside an optical axis of the optical system and which corresponds in terms of its shape to the light source, and the detector elements are arranged in such a way that profiles of a radiation property registered by the detector elements are different from each other and a focus position is set in a manner dependent on the profiles.