Light Microscope Stages

Written by microscopes

Monday, 06 August 2007

Information on the types of Light Microscope Stages.

Simple Light Microscope Stages

These may be divided into three classes, ordinary, semi-mechanical, and mechanical.

Ordinary Microscope Stages

Ordinary Microscope Stages consist of a plain plate, either round or square, on which the slide is held by means of the clips. As the microscope is used principally in an inclined position, the pressure exerted by the clips must be sufficient to retain the slide firmly in position. This causes a certain amount of friction between the lower surface of the slide and the upper one of the stage, which at times is very annoying, in that it is difficult to move the object to a point desired, with certainty. The motion is "jerky" and disagreeably harsh unless the stage is very clean.

A large number of plans have been devised to overcome this difficulty, which have proven very efficient. They may be termed semi-mechanical, in that the fingers do not come in direct contact with the slide. Usually glass is brought in contact with the metal, but so arranged as to offer as few and small points of contact as possible.

A so-called glass-stage and slidecarrier, in which the stage is merely for the support of the slide-carrier. This latter is arranged to receive the slide and rests upon the glass by small points. At its ends are two projecting tongues which are bent downward and inward and act as springs against the lower surface of the glass plate. While the movements must be carried out by the hands, they are smooth and steady and work with ease, even under high powers.

Mechanical Microscope Stages

The mechanical stage is in every sense mechanical. The hands do not come in contact with the slide except to place it on the stage. Two movements are usually provided at right angles to one another, either both with rack and pinion adjustment, or one with rack and pinion while the other has a screw motion. Examinations can be carried out with ease and reliability under the highest powers. The main value of the mechanical stage is that systematic examinations over the entire surface of an object can be carried on.