Light-emitting diode illumination system for an optical observation device, in particular a stereomicroscope or stereo surgical microscope

1. An illumination apparatus for a surgical microscope, the illumination apparatus comprising:

an LED arrangement including a plurality of light-emitting diodes (LEDs) each emitting non-white light;

a multi-arm light guide located after the LED arrangement, the multi-arm light guide including a coupler defining a single light exit end, wherein the multi-arm light guide includes one light guide arm associated with each of the plurality of LEDs, each of the light guide arms having a light-accepting end arranged to receive light from the associated LED, whereby light leaving the light guide through the light exit end is mixed to provide white illuminating light for the surgical microscope;

a plurality of filters arranged one between each of the light guide arms and the LED associated therewith;

a light-sensitive measurement sensor;

at least one additional light guide arm arranged to direct light from the coupler to the measurement sensor, wherein the light from the coupler includes light reflected from an observed specimen; and

a signal processing unit connected to the measurement sensor and to the plurality of LEDs and the plurality of filters, wherein the intensity and spectral composition of the light of the individual light-emitting diodes and the filters, are controlled by the signal processing unit.

2. The illumination apparatus according to claim 1 , wherein the plurality of LEDs includes at least one red-light-emitting LED, at least one green-light-emitting LED, and at least one blue-light-emitting LED.

3. The illumination apparatus according to claim 1 , wherein the plurality of LEDs includes at least one yellow-light-emitting LED and at least one blue-light-emitting LED.

4. The illumination apparatus as defined in claim 1 , wherein each of the light guide arms includes a plurality of optical fibers, and the optical fibers of the light guide arms are mixed together with one another in the coupler.

5. The illumination apparatus as defined in claim 1 , wherein the light guide is flexible.

6. The illumination apparatus as defined in claim 1 , wherein the light accepting ends of the light guide arms are hot-melted.

7. The illumination apparatus as defined in claim 1 , wherein the light exit end of the light guide is hot-melted.

8. The illumination apparatus as defined in claim 1 , wherein the light guide comprises a light-guiding rod system.

9. The illumination apparatus as defined in claim 1 , wherein the light guide is designed as a cross-section changer to allow for numerical aperture adaptation.

10. The illumination apparatus as defined in claim 1 , wherein the plurality of light-emitting diodes includes at least one laser diode.

11. An apparatus comprising:

a microscope;

an LED arrangement including a plurality of light-emitting diodes (LEDs) each emitting non-white light, the LED arrangement being located outside of the microscope;

a multi-arm light guide located after the LED arrangement, the multi-arm light guide including a coupler defining a single light exit end, wherein the multi-arm light guide includes one light guide arm associated with each of the plurality of LEDs, each of the light guide arms having a light-accepting end arranged to receive light from the associated LED, whereby light leaving the light guide through the light exit end is mixed to provide white illuminating light for the microscope;

a plurality of filters arranged one between each of the light guide arms and the LED associated therewith;

a light-sensitive measurement sensor;

at least one additional light guide arm arranged to direct light from the coupler to the measurement sensor, wherein the light from the coupler includes light reflected from an observed specimen; and

a signal processing unit connected to the measurement sensor and to the plurality of LEDs and the plurality of filters, wherein the intensity and spectral composition of the light of the individual light-emitting diodes and the filters are controlled by the signal processing unit to achieve a desired spectrum.

12. The apparatus as defined in claim 11 , further comprising a camera associated with the microscope.

13. The apparatus as defined in claim 12 , further comprising a computer connected to the camera.

14. The apparatus as defined in claim 13 , further comprising a display associated with the microscope, wherein the display is connected to the camera and/or to the computer.

15. The apparatus as defined in claim 14 , wherein the computer includes a memory unit for storing image data constituting false-color images, wherein the false-color images are retrievable by the display and can be reflected into at least one observation beam path of the microscope.