The standard light microscope, called a compound microscope, uses two aligned lens systems; the first located in the objective and the second in the eyepiece. They are especially used for examining objects that are transparent, or cut into sheets so thin that they become transparent. It took about 150 years of development before compound microscope optics were able to provide the same image quality as Van Leeuwenhoek’s simple microscopes, due to difficulties in the multiple lenses it uses
Parts or components of a compound microscope
They can be seen in this figure taken from Wikipedia:
- Eyepiece (A): lens located at the top of the optical tube, close to the observer’s eye. Captures and enlarges the image formed in the objectives.
- Objective (B): lens located in the lower part of the optical tube, on the revolver. It enlarges the image, it is an essential element that allows you to see through the eyepieces.
- Head: it is the upper part of the modern microscope that groups the eyepieces.
- Condenser (D):lens that concentrates the light rays on the preparation, object to be observed and they come from the light source.
- Diaphragm:regulates the amount of light that reaches the condenser.
- Focus (F): directs the light rays towards the condenser.
- Optical tube: it is the dark chamber that carries the eyepiece and the objectives. It can be attached to the support shaft or arm by a zipper to allow focus.
- Revolver: it is the piece that carries the objectives of different magnifications, and that rotates to be able to use one or the other, aligning them with the eyepiece.
- Macro and Micrometer Screws: These are fine and coarse focus screws, they move the stage or tube up and down. The coarse, allows wide displacements for an initial focus and the micrometric, very short displacements, for the most precise focus.
- Stage (E): it is a horizontal platform with a central hole, on which the object to be observed (the preparation) is placed, which allows the passage of rays from the light source located below.
- Holding Clamps: two clamps, serve to retain the slide on the stage and a rack system that allows the preparation to be moved.
- Arm: it is the support axis, the structure that holds the tube, the stage and the focus screws associated with the tube or stage. The union with the base can be articulated or fixed, this determines that the microscope is fixed or tiltable.
- Base or foot: also called a stand. It is the lower part of the microscope that gives it stability, it is usually made of iron and has very different designs.