Information on the Compound Light Microscope

A compound light microscope (CLM) is an advanced piece of lab equipment that utilizes light to create magnified images of specimens that are then projected onto an imaging mechanism. The term "compound" refers to the combination of lenses on the microscope that cause the magnification of objects. CLMs are very expensive with prices into the thousands of dollars and must be handled carefully so their precision remains intact.

Parts

• Compound light microscopes are made up of several parts including: objective and condenser lenses, eyepieces or ocular lenses, a lamp collector and socket, stage, polarizers, retarders, filters, condenser and field stop diaphragms and focus knobs.

Lenses

• Although it is easy to assume CLMs make use of a few lenses, the reality is that the scope's lenses are a combination of several lens layers cemented together. The objective lens is the one the specimen is initially formed on, then the ocular lens magnifies that image and the two combined produce a final virtual or real image.

Eyepieces

• CLMs can have one to three eyepieces, the circular tubes you look into, making them monocular, binocular or trinocular. Typically the third eyepiece is used for photographic purposes. Most compound light microscope eyepieces have a magnification power of 10 times, making it possible to see bacteria, human and animal cells and algae.

Darkfield

• Darkfield microscopes are CLMs modified for specialty purposes. They make use of condensers that cause a black disc to cover the light path making side illumination of objects appear against the dark background. These microscopes are beneficial when viewing live and unstained specimens (like those from a tissue culture).

Polarizing

• Polarizing microscopes are CLMs to which a polarizer, analyzer and compensator have been attached causing polarized light to shine through specimens for analysis. These scopes are commonly used by geologists in the study of rocks, gems and minerals.