Method and array for detecting the position of a plane scanned with a laser scanner

An arrangement for determining the position of the plane XY of an object, which plane XY is to be scanned, and for its positioning in the focal plane X′Y′ of a laser scanner, comprising:

• an object holder for receiving the object;
• a photo-sensitive position detector for locating the reflections of three points P1, P2, P3 which lie in plane XY and are sampled by a laser beam;
• an evaluating circuit for determining the deviation of the actual position value of each of these reflections from its reference position value on the detector;
• and
• an adjusting device connected with the evaluating circuit for changing the inclination of the object holder relative to the focal plane X′Y′ of the laser scanner.

A method for orienting the plane of a specimen under study to a focal plane of a laser scanner, the method comprising:

• directing a laser beam to at least three points lying in a specimen plane;
• imaging each of the reflections proceeding from the three points using a position-sensitive detector;
• determining, for each point, the difference between an actual position based on the imaged reflection impinging on the position sensitive detector and a corresponding position on the focal plane;
• and
• changing the inclination of the specimen relative to the focal plane to align the three points lying in the specimen plane with the focal plane of the laser scanner.