Device for stabilizing the focus of a microscope

A device for stabilizing the focus in a microscope, the microscope having an objective and a specimen stage which, for the purpose of setting the focus, is constructed such that it can be adjusted in height along an objective axis by a drive gear and a toothed rack, and having a body of the microscope in which generate heat and cause a displacement, caused by heat, in distance of the specimen stage relative to the objective, and thus cause defocusing, said device comprising:

• at least two rods of different thermal expansion for compensating for the defocusing caused by heat, said rods being interposed between the toothed rack and the specimen stage, the second rod being connected with one of its ends to the toothed rack and with its other end to one end of the first rod, and the first rod bearing the specimen stage with its other end, said first rod counteracting the thermal elongation of the second rod and thus the displacement of the specimen stage through the thermal elongation of the first rod due to heat, wherein the specimen stage is tracked in distance as a function of temperature as a consequence of the different thermal expansions of the two rods.