Answer :
phase contract microscope is an optical microscopy technique that converts phase shifts in light passing through a transparent specimen to brightness change in the image.
the basic principle to make phase changes visible in phase contrast microscope is to separate the illuminating background light from the specimen scattered light.which make up the foreground details, and to manipulate these differently.
the basic principle to make phase changes visible in phase contrast microscope is to separate the illuminating background light from the specimen scattered light.which make up the foreground details, and to manipulate these differently.