In this article we will discuss about the design of a compound microscope with the help of diagram.
Compound microscope is a very useful optical instrument. It gives a high magnification necessary for working out the details of minute organisms and also for studying the internal structures of plants and animals. The instrument rests on a horse-shoe-shaped base (foot) with a short pillar.
There may occur an inclination joint at the upper end of the pillar where the main body of the apparatus remains screwed. It bears a stage (platform) with a central hole and a pair of clips. Below the stage lies a sub-stage consisting of a condenser and an iris-diaphragm. Light is focused from a mirror attached to the pillar.
Condenser is there to concentrate light and the diaphragm for regulating it. The body of the compound microscope has an arm, often bent, with an attached body tube having another tube inside known as draw tube which is graduated in millimetres. At the upper end of the body tube occurs the eyepiece.
Two objectives—low-power and high- power—remain fitted on a revolving nosepiece at the lower end of the body tube. Two adjustment screws—coarse and fine—work on rack and pinion system for bringing the object under proper focus.
The material to be seen under the compound microscope should be sufficiently thin so that light may pass through it. It should be mounted in a liquid medium on a clean glass slide and covered with a cover-slip. Now it has to be placed on the stage taking care that the material lies at the centre of the hole and clipped.
Light should be focused properly and the body tube with lower-power objective is to be brought down with the help of coarse adjustment screw to such a level that the distance between the slide and the objective is roughly 1/4 inch.
Having put the eye on the eyepiece the objective is to be raised slowly till a clear vision is achieved. For still higher magnification low-power objective is to be removed and the high-power objective brought in and only the fine adjustment screw is to be used for adjustment.