Patent ID: 7706076

Claim:
An optical system for arranging between a light source and a field diaphragm in an illumination beam path of a microscope, comprising: n imaging optical elements with focal lengths f i and Abbe numbers ν i (i=1, . . . , n) and for which the following relationship is met: ∑ i = 1 n ⁢ h i f i · v i ≤ 0.07 , where h i is one half of the bundle diameter of a bundle of light rays proceeding from a point of the light source at the entrance to the imaging optical element I; wherein the n optical elements comprise a partial system which serves to image the light source from infinity to an intermediate image in the optical system, has a focal length f and comprises in direction of the beam path proceeding from the light source: a first converging lens with a focal length f i where 0.3·f<f i <0.7·f, a diverging lens with a focal length f 2 where −0.2·f<f 2 <−0.4·f, a second converging lens with a focal length f 3 where 0.3·f<f 3 <0.7·f, and a third converging lens with a focal length f 4 where 0.8·f<f 4 <2·f, wherein the distance of the third converging lens from the second converging lens ( 20 ) is between 0.6·f and 1.2·f.