System and method for increasing the contrast of an image produced by an epifluorescence microscope

Abstract

The contrast of an image produced by epifluorescence microscopy may be increased by placing a dichroic reflector behind the sample. The dichroic reflector reflects the emission light emitted by the fluorescent tags in the sample back through the objective lens while allowing the shorter wavelength excitation light to pass through the sample holder.

1 . A glass slide for supporting a biological sample comprising a top surface and a bottom surface and a sample reflector disposed behind the sample.  
   
   
       2 . The glass slide in  claim 1  wherein said sample reflector is a dichroic reflector.  
   
   
       3 . The glass slide in  claim 2  wherein said dichroic reflector reflects emission light and not excitation light.  
   
   
       4 . The glass slide in  claim 2  wherein the dichroic reflector is a dichroic film.  
   
   
       5 . The glass slide in  claim 1  wherein said reflector is shaped into a concave surface having a focal point in the plane of the sample.  
   
   
       6 . A method for creating a high contrast image of a fluorescent biological sample on a slide having a reflector surface thereon, the method comprising the steps of: 
 illuminating said sample to cause fluorescent emission,    collecting directly a first portion of said emission,    reflecting a second portion of said emission by said reflector surface,    collecting said second portion of said emission concurrently with said first portion at the same locus.    
   
   
       7 . The method in  claim 6  wherein said reflector surface is a dichroic reflector.  
   
   
       8 . The method in  claim 7  wherein the dichroic reflector reflects said emission but not said excitation.