Abstract: An optical system for imaging the surface of the bottom of a well of a microtiter plate made of a transparent material. This surface has an analysis preparation. The optical system comprises an enlarging lens and an incident-light illumination formed by a ring-shape, diffuse light source. The incident light illumination is arranged concentrically with the optical axis. The microtiter plate is illuminated from the backside by an approximately dot-shaped light source, which is arranged behind the diffuser disk and centered in relation to the optical axis. Reflections and material flaws in the area located outside of the measuring area to be evaluated are thus made invisible.

Abstract: An optical system for imaging the surface of the bottom of a well of a microtiter plate made of a transparent material. This surface has an analysis preparation. The optical system comprises an enlarging lens and an incident-light illumination formed by a ring-shape, diffuse light source. The incident light illumination is arranged concentrically with the optical axis. The microtiter plate is illuminated from the backside by an approximately dot-shaped light source, which is arranged behind the diffuser disk and centered in relation to the optical axis. Reflections and material flaws in the area located outside of the measuring area to be evaluated are thus made invisible.

Abstract: To image the surface, provided with an analysis preparation, of the bottom of a well of a microtiter plate (16) made of a transparent material, provision is made for an optical system with a magnifying objective and an incident-light illumination formed by an annular, diffuse light source (15) which is arranged concentrically with the optical axis (19). The microtiter plate (16) has its rear side illuminated by an approximately point-shaped light source (17) arranged behind a diffuser disk (18) and located centrally relative to the optical axis (19). Reflections and material interferences occurring in the area lying outside the measurement surface subject to evaluation are thereby rendered invisible.