Optical microscopes use visible light and a system of lenses to magnify small samples that are usually un-seen to the bare eye. The optical microscope is the first, oldest and simples type of microscope (as opposed to the much more advanced electronic microscope). The first optical microscopes were created in the 18th century. Due to it's compact sizes, simplicity and relatively low price, the optical microscope is very popular, and can be found in use in many areas of biology. Optical microscopes mostly magnify objects for up to 1500 times.



The first optical microscopes were structured in a way that is called "the simple microscope". This structure utilizes only one pair of lenses to create a magnified image of the sample. Today, the simple structure is in use only in the magnifying glass, hand lens and the loupe.

The more advances optical microscopes, and the ones that are popular today, are what's called "compound optical microscopes". These microscopes use a system of many lenses, in order to "compound" and multiply the magnification, and therefore maximize it. The two main lens systems in an optical microscope are the objective lens (near the examined object), and the eyepiece lens (up near the eye of the scientist). Modern optical microscopes use multiple lenses both in the objective part as well as the eyepiece part.

The old optical microscopes also used a mirror to provide illumination below the object. The modern optical microscopes use a strong lamp to provide constant and strong illumination.

So what are optical microscopes used for now a days?

The main uses of compound optical microscopes include:

The examining small pieces of material, or even a smear or a squash preparation. This is due to the fact that the optical microscope uses light to pass beneath the object and enter the lenses. That's why the item is better be half-transparent. In other uses the optical microscope may be used to examine metal samples, in order to study the metal's structure.

At low power, microscopes can be used to examine small living animals and plants. At high power, they can be used to examine bacteria.

It is important to note that the vast advancement in medicinal fields and biology in general, is owed to a large extent, to the invention of the optical microscopes. For example, the way the blood flows in our body was not fully understood until the microscope made in possible to examine small blood vessels behavior.