A compound microscope uses a very short focal length objective lens to form a greatly enlarged image. In the compound microscope magnification is achieved in two stages. For magnification it utilizes an
- objective lens ; lens closet to the object; and
- An eyepiece or ocular lens that one look into it and that is used to further magnify the image formed by the objective lens.
Compound microscopes may have one or two binocular heads for the viewer to examine microscopic organisms, collectively called specimens. The compound microscope also has mechanism to illuminate the specimen for better viewing. The viewing of the specimen is achieved through the interaction of light and the lenses positioned above the specimen. The objective lenses are usually adjustable in order to magnify the specimen. The eyepiece serves as the viewer’s main window into viewing the microscopic organism.
A light source illuminates the object to be seen is an important part of the compound micrscope. That source can be a mirror, or the instrument can be self-illuminating. As light passes through the object, the objective lens nearest the object produces an enlarged image of the object in the primary image angle. The ocular lens o eyepiece acts as a magnifier and produces an enlarged image of the image produced by the objective lens.
Basic parts of a compound microscope
Three basic parts of the compound microscope are head, arm and base.
- Head; also called the body of the microscope. This part is located at the upper part of the microscope. It is where the optical mechanisms are.
- Arm; it is located below the head of the microscope. This part serves as the backbone of the compound microscope. It connects the head and the base.
- Base; The bottom-most part of the microscope, which contains the illuminator.
Optical components of a compound microscope
The optical components of the compound microscope are the following:
- the eyepiece,
- the eyepiece tube,
- the objective lenses,
- the nosepiece,
- coarse and fine focus knobs,
- the stage,
- the stage clips,
- the aperture,
- the illuminator,
- the condenser,
- the iris diaphragm and
- Condenser focus knob.
Figure of a compound microscope showing different parts
Major application areas of compound microscope
- Hospitals
- Microbiology
- Cell biology
- Research and development
- Microbiological study
- Medical diagnostics
- Medical research