Surgical microscope having an illumination apparatus

Abstract

A surgical microscope for visualizing a tissue region contains an illumination device with a light source and an illumination beam path for illuminating an object region with an object plane and an observation device having an observation beam path for imaging the object region with the object plane into an observation plane. A first polarizer can be coupled into the illumination beam path and is suitable for polarizing the illumination light in a first orientation. A polarizer, which can be coupled into the observation beam path, has a second orientation at an angle between 80° and 100° relative to the first orientation. In a first mode, the light source emits illumination light in a first wavelength range between 450 nm and 550 nm, the first polarizer is coupled into the illumination beam path, and the second polarizer is coupled into the observation beam path.

What is claimed is: 
     
         1 . A surgical microscope for visualizing a tissue region, the surgical microscope comprising:
 an illumination device including a light source configured to emit illumination light to propagate along an illumination beam path and to illuminate an object region including an object plane;   an observation device defining an observation beam path and being configured to image the object region into an observation plane;   a first polarizer configured to be coupled into the illumination beam path and having a first orientation to polarize the illumination light;   a second polarizer configured to be coupled into the observation beam path and having a second orientation at an angle between 80° and 100° relative to the first orientation,   wherein, in a first mode:   the light source emits the illumination light in a first wavelength range between 430 nm and 570 nm,   the first polarizer is coupled into the illumination beam path, and   the second polarizer is coupled into the observation beam path.   
     
     
         2 . The surgical microscope as claimed in  claim 1 , wherein, in a second mode:
 the light source emits the illumination light as white light,   the first polarizer is coupled out of the illumination beam path, and   the second polarizer is coupled out of the observation beam path.   
     
     
         3 . The surgical microscope as claimed in  claim 1 , wherein the first orientation of the first polarizer and the second orientation of the second polarizer are orthogonal relative to one another. 
     
     
         4 . The surgical microscope as claimed in  claim 1 , wherein:
 the light source is a light-emitting diode light source and includes at least a first individual light source, a second individual light source, and a third individual light source,   the first individual light source emits the illumination light in a red wavelength range between 600 nm and 640 nm,   the second individual light source emits the illumination light in a green wavelength range between 500 nm and 570 nm, and   the third individual light source emits the illumination light in a blue wavelength range between 430 nm and 480 nm.   
     
     
         5 . The surgical microscope as claimed in  claim 4 , wherein:
 in the first mode, the light-emitting diode light source emits the illumination light only from the second individual light source and the third individual light source, and   in the second mode, the light-emitting diode light source emits the illumination light from the first individual light source, the second individual light source, and the third individual light source.   
     
     
         6 . The surgical microscope as claimed in  claim 1 , further comprising a red filter, wherein:
 the light source is a white light source which emits the illumination light in a wavelength range between 450 nm and 620 nm,   in the first mode, the red filter is coupled into the illumination beam path and configured to cause an attenuation of larger than 90% of light having a wavelength longer than 620 nm.   
     
     
         7 . The surgical microscope as claimed in  claim 1 , further comprising:
 a switch configured to switch between the first mode and the second mode.   
     
     
         8 . The surgical microscope as claimed in  claim 7 , wherein the switch is an element of a graphical user interface or a member of a foot control panel. 
     
     
         9 . The surgical microscope as claimed in  claim 1 , further comprising:
 at least one camera arranged in the observation beam path and configured to record the object plane.   
     
     
         10 . The surgical microscope as claimed in  claim 1 , wherein, in the first mode, an intensity of the illumination light in a first wavelength range between 430 nm to 570 nm is larger than the intensity in the remaining wavelength ranges by at least a factor of 5. 
     
     
         11 . The surgical microscope as claimed in  claim 10 , wherein, in the first mode, the light source emits the illumination light only in the first wavelength range between 430 nm and 570 nm. 
     
     
         12 . A method for visualizing an object region with the surgical microscope as claimed in  claim 1 , the method comprising:
 coupling the first polarizer into the illumination beam path;   orienting the first polarizer in the first direction to polarize the illumination light,   illuminating the object region in the object plane with the illumination light in the first mode, wherein the illumination light is polarized in the first orientation and has a first wavelength range between 430 nm and 570 nm;   coupling the second polarizer into the observation beam path;   orienting the second polarizer to have the second orientation at the angle between 80° and 100° relative to the first orientation; and   observing the illuminated object region with the observation device through the observation beam path.   
     
     
         13 . The method as claimed in  claim 12 , further comprising:
 limiting a visualization of the object region in the first mode to a depth in a range between 300 μm to 800 μm.   
     
     
         14 . The method as claimed in  claim 12 , wherein, in the first mode, an intensity of the illumination light in the first wavelength range between 430 nm to 570 nm is larger than the intensity in the remaining wavelength ranges by at least a factor of 5. 
     
     
         15 . The method as claimed in  claim 14 , wherein, in the first mode, the light source emits the illumination light only in the first wavelength range between 430 nm and 570 nm. 
     
     
         16 . A surgical microscope for visualizing a tissue region, the surgical microscope comprising:
 an illumination device including a light source configured to emit illumination light to propagate along an illumination beam path and to illuminate an object region including an object plane;   an observation device defining an observation beam path and being configured to image the object region into an observation plane;   a first polarizer configured to be coupled into the illumination beam path and having a first orientation to polarize the illumination light;   a second polarizer configured to be coupled into the observation beam path and having a second orientation at an angle between 80° and 100° relative to the first orientation,   wherein, in a first mode:   the light source emits the illumination light with a wavelength within an absorption spectrum of hemoglobin and in a wavelength region below 570 nm,   the first polarizer is coupled into the illumination beam path, and   the second polarizer is coupled into the observation beam path.   
     
     
         17 . The surgical microscope as claimed in  claim 16 , wherein, in the first mode, an intensity of the illumination light in the wavelength range above 570 nm is lower than the intensity in the remaining wavelength ranges by at least a factor of 5. 
     
     
         18 . A method for visualizing an object region, the method comprising:
 providing an illumination device including a light source emitting illumination light to propagate along an illumination beam path and to illuminate an object region including an object plane and a first polarizer configured to be coupled into the illumination beam path;   coupling the first polarizer into the illumination beam path and orienting the first polarizer in a first orientation to polarize the illumination light;   illuminating, in a first mode, the object region in the object plane with the illumination light polarized in the first orientation, wherein a wavelength of the illumination light is in a first wavelength region within an absorption spectrum of hemoglobin and below 570 nm;   coupling a second polarizer having a second orientation at an angle between 80° and 100° relative to the first orientation into an observation beam path of an observation apparatus;   imaging the object region into an observation plane along the observation beam path; and   observing the object region imaged into the observation plane with the observation apparatus.   
     
     
         19 . The method as claimed in  claim 18 , wherein, in the first mode, an intensity of the illumination light in the wavelength range above 570 nm is lower than the intensity in the remaining wavelength ranges by at least a factor of 5. 
     
     
         20 . The method as claimed in  claim 18 , further comprising:
 limiting a visualization of the object region in the first mode to a depth in a range between 300 μm to 800 μm.