Position sensitive light spot detector

Abstract

The present invention provides a method and an apparatus for detecting a position of a light spot in a light distribution that can include stray light components (e.g. from other lasers, ambient lighting etc.) The apparatus includes a continous response position sensitive detector (CRPSD, e.g. lateral effect photo-iode) for determining a first centroid of the light distribution and a discrete response position sensitive detector (DRPSD, e.g. multiplexed array) for determining a second centroid of the light distribution within a reading window defined about the first centroid and within the light distribution. The second centroid represents the position of the light spot in the light distribution. This multiple stage approach exploits the high resolution and speed offered by traditional CRPSDs together with the accuracy under variable lighting conditions offered by traditional DRPSDs.

Dependencies are inferred from the claim text.