TRANSILLUMINATION DEVICE AND METHOD FOR LIGHT MICROSCOPES, AND A MICROSCOPE SYSTEM

The invention relates to an apparatus for transmitted light illumination for light microscopes having changing effective entrance pupil of an objective. The apparatus has a light source for emitting an illuminating light beam, and a holding device for holding a sample to be examined, and at least one diaphragm edge for trimming the illuminating light beam bundle, wherein the diaphragm edge is arranged between the holding device and the light source and extends transversely to an optical axis, wherein a beam path of the illuminating light between the diaphragm edge and a sample held by the holding device is free from beam focussing components. The apparatus is characterized in that the means are provided for enquiring concerning a microscope setting and/or a microscope configuration of a light microscope, which means are positionable at the device for transmitted light illumination; means are provided for variable positioning of the diaphragm edge in a direction transverse to the optical axis, and a control device is provided and configured to position the diaphragm edge in the direction transverse to the optical axis via the means for variable positioning. The invention also relates to a method for transmitted light illumination for a light microscope and a microscope system.