Patent ID: 8379304

Claim:
A dark field microscope comprising: a light source for emitting illumination light; a light collecting optical system including a light collecting side condenser lens for collecting the illumination light from the light source to illuminate an observation sample; and an image forming optical system including an objective lens for receiving scattered light from the observation sample to form a magnified image of the sample, wherein the light collecting optical system is configured such that the light collecting side condenser lens is a long focal distance lens, and the illumination light is illuminated on the observation sample only through a low numerical aperture area; and the image forming optical system is configured such that a light shielding member for constantly shielding the entire beam of the illumination light is provided at an image forming center of a conjugate image of a back focal plane of the image forming optical system, and only the scattered light emitted from the objective lens is collected on an imaging area to obtain a dark field image of the observation sample.