Autofocusing arrangement for a stereomicroscope which permits automatic focusing on objects on which reflections occur

An autofocusing arrangement for a stereomicroscope defining first and second viewing beam paths for viewing an object through an objective by utilizing only a selected region thereof leaving a remaining region thereof unused for the purpose of viewing the object via said beam paths, the autofocusing arrangement comprising:

• light source means for supplying a projection beam defining a projection beam path;
• said projection beam having a predetermined cross section;
• optical focusing means for converting the entire cross section of said projection beam into a bar-shaped marking image;
• said optical focusing means being disposed between said light source means and said objective;
• collimating and deflecting means for imaging said bar-shaped image through said objective at said remaining region thereof and onto the object with at least one dimension having limited diffraction whereupon said projection beam is reflected from the object along one of said viewing beam paths;
• outcoupling means arranged in said one viewing beam path for coupling the reflected projection beam out of said one viewing beam path;
• a light-sensitive resolving position detector arranged downstream of said outcoupling means and including a plurality of elements producing a plurality of signals, respectively, indicative of a shift of said bar-shaped marking image and a defocusing of said stereomicroscope;
• an evaluation unit for converting said signals into a drive signal for refocusing and stereomicroscope;
• and,
• focusing motor means for refocusing said stereomicroscope in response to said drive signal.