Surgical microscope having an illuminating system and control unit therefor

1. A surgical microscope comprising:

a viewing optic for enabling a viewer to view a magnified representation of a region of an object in a viewing area;

said viewing optic defining a viewing beam path and including a continuously adjustable magnification system arranged in said viewing beam path;

a viewing-optic adjusting unit assigned to said magnification system;

an adjustable illuminating system for making illuminating light available for illuminating the object region in an adjustable illuminated area thereof with said illuminating light;

said illuminating system including: a light source for supplying said illuminating light a unit for adjusting an illuminating luminous flux of said illuminating light from said light source; and, an optic component assembly for adjusting the size of said illuminated area;

an illuminating-system control unit connected to said viewing-optic adjusting unit and being adapted to receive information as to the adjusted magnification of said viewing optic;

said illuminating-system control unit being operatively connected to said illuminating system for adjusting said illuminating system to adapt the size of said illuminated area to the size of said viewing area; and,

said illuminating-system control unit controlling said illuminating system in dependence upon the adjusted magnification of said viewing optic so as to adapt, in a first magnification range, wherein a transmission of said viewing optic is substantially constant, the size of said illuminated area in said object region while a constant irradiation intensity of said illuminating light is maintained and to adapt, in a second magnification range lying above said first magnification range, wherein the transmission of said viewing optic in said second magnification range decreases with increasing magnification, the size of said illuminated area while said irradiation intensity is simultaneously changed,

so that the brightness impression of viewed images for the viewer is constant over said first magnification range and over said second magnification range.

2. The surgical microscope of claim 1 , wherein said adjustable optic component assembly includes at least one displaceable lens element.

3. The surgical microscope of claim 2 , wherein said adjustable optic component assembly includes an adjustable illuminated field diaphragm.

4. The surgical microscope of claim 3 , wherein said optic component assembly further comprises a common drive unit for displacing said lens element and adjusting said illuminated field diaphragm.

5. The surgical microscope of claim 4 , wherein said drive unit comprises a rotatable shaft.

6. The surgical microscope of claim 5 , wherein said common drive unit further comprises an electric motor operatively connected to said rotatable shaft.

7. The surgical microscope of claim 5 , wherein said common drive unit further comprises a rotary knob assigned to said rotatable shaft.

8. The surgical microscope of claim 4 , further comprising an illuminated field diaphragm adjusting mechanism; and, said common drive unit acting on said illuminated field diaphragm adjusting mechanism so as to cause a drive force, which is introduced into said common drive unit, to be transmitted to said illuminated field diaphragm when opening said illuminated field diaphragm and when closing said illuminated field diaphragm.

9. The surgical microscope of claim 1 , wherein said illuminating system further comprises an apertured diaphragm for adjusting an illuminating light flux.

10. The surgical microscope of claim 1 , further comprising an adjusting unit assigned to said magnification system for adjusting the magnification of said viewing optic to a value selectable by the viewer.

11. A surgical microscope comprising:

a viewing optic for enabling a viewer to view a magnified representation of a region of an object in a viewing area with a constant brightness impression;

said viewing optic including a continuously adjustable magnification system to which a viewing-optic adjusting unit is assigned;

an adjustable illuminating system for making illuminating light available for illuminating the object region in an adjustable illuminated area thereof with said illuminating light;

said illumination system including: a light source for supplying said illuminating light; a unit for adjusting an illuminating luminous flux of said illuminating light from said light source; and an adjustable optic component assembly for adjusting the size of said illuminated area, comprising at least one adjustable illuminated field diaphragm and at least one displaceable lens element;

an illuminating-system control unit connected to said viewing-optic adjusting unit and being adapted to receive information as to the adjusted magnification of said viewing optic, said illuminating-system control unit being operatively connected to said illumination system for adjusting said illumination system to adapt the size of said illuminated area to the size of said viewing area;

said illuminating-system control unit controlling said illumination system in dependence upon the adjusted magnification of said viewing optic so as to adapt, in a first magnification range, the size of said illuminated area in said object region while maintaining a constant irradiation intensity of said illuminating light by adjusting said displaceable lens element, and to adapt, in a second magnification range lying above said first magnification range, the size of said illuminated area by adjusting said adjustable illuminated field diaphragm while simultaneously changing said irradiation intensity,

so that the brightness impression of viewed images for the viewer is constant over the first magnification range and the second magnification range.