phase-con|trast microscope

phase-con|trast microscope «FAYZ KON trast»,

a microscope which uses the differences in phase of light passing through or reflected by the object under examination, to form distinct and contrastive images of different parts of the object: »

The phase-contrast microscope…has made it possible to observe in living cells structures which previously could be seen only if the cells were killed and stained (Scientific American).