Write short notes on dark field microscope.

Explanation

(i) The dark field microscope was discovered by Z. Sigmondy (1905). Here the field will be dark but object will be glistening so the appearance will be bright.
(ii) A special effect in an ordinary microscope is brought about by means of a special component called .Patch Stop Carrier..
(iii) It is fixed in metal ring of the condenser component.
(iv) Patch stop is a small glass device which has a dark patch at centre of the disc leaving a small area along the margin through which the light passes.
(v) The light passing through the margin will travel oblique like a hollow cone and strikes the object in the periphery, therefore the specimen appears glistening in a dark background.