OPERATIONCarl Zeiss Illumination and Contrast Techniques in Transmitted Light Axio Vert.A180 431030-7044-001 05/2012Fig. 4-7 VAREL Contrast Pupil Images4.11.4 Transmitted Light Differential Interference Contrast (DIC)The transmitted light DIC technique permits a high-contrast, plastic imaging of transparent specimendetails. The light linearly polarized by a polarizer is split into two partial beams in a birefringent prism.These beams pass through two neighboring areas of the specimen at a close distance and experiencepath differences there due to differences in refractive index and specimen thickness. The two partialbeams are subsequently merged in a second birefringent prism and end up with the same vibrationdirection after passing through the analyzer. Consequently, the two partial beams can interfere with oneanother in the intermediate image, with the path differences resulting in different gray values(intensities).Requirements− The microscope must have properly been put into operation, as described in Section 3.− The microscope must be switched on.− Condenser 0.4 with modulator disk and built-in DIC I/0.4 or DIC II/0.4 condenser moduleorcondenser 0.55 with modulator disk and built-in DIC I/0.55, DIC II/0.55 orDIC III/0.55 condenser module (Each condenser module comes with a built-in polarizer.)− Objectives for DIC contrast− DIC slider matching the objectives used− D P&C analyzer module in the reflector turret or three-position contrast slider (10 mm x 29 mm) withbuilt-in analyzer for the contrast slider− Specimen vessel with glass bottomMoving the VAREL illumination all the way to a position outside of the pupil corresponds tounilateral DF illumination.Moving the VAREL illumination between the Ph and VAREL rings of the objectivecorresponds to oblique HF illumination.
