Abbe condenser | Abbe condenser

Key Words: Aplanatic objective, depth-of-field, magnification, N.A.

Definition:A high N.A. condenser positioned below the microscope stage that concentrates and focuses light passing through the specimen and entering the objective

TECHNOLOGY:

The Abbe condenser (invented by Ernst Abbe in 1870) is a high N.A. condenser that is generally used to concentrate and focus light when using high power objectives (40x and above) as these tend to have very small aperture diameters. It is suitable for most brightfield and phase contrast applications. The Abbe condenser, which typically incorporates two uncorrected lenses and an iris diaphragm results in increased illumination and resolution. Users can control brightness, contrast, depth of field, and evenness of illumination of light during imaging by moving the condenser closer to, or further from, the objective and / or by regulating the condenser's iris diaphragm, which controls the diameter of the light beam. In general for best results, the condenser lens should have a N.A. equal to or greater than the N.A. of the objective.