Patent ID: 6836358
Filing Date: 2004-12-28
Classification: G02B

Abstract:
An illumination optical system for a microscope, comprisinga light source, an illumination lens system that gathers light from said light source and directs the light toward a sample to be viewed, an object optical system positioned between said illumination lens system and said sample, the improvement of: making adjustable one of the light source position along the optical axis, or the focal length of the illumination optical system, so that illumination state changes from Koehler illumination to critical illumination, respectively, the following condition is satisfied: 0.15aÂ·f2)/(bÂ·f1)|<0.5 where a is the diameter of the light source, b is the diameter of the microscope field of view, f1 is the focal length of the illumination lens system, and f2 is the focal length of the object optical system.