A microscope is probably the most well-know and well-used research tool in biology and its related disciplines. Generally they are classified into several different classes based on what interacts with sample under study to generate the desired visible image. For instance, there are three types of microscopes such as optical microscopes (light microscope or compound microscope), electron microscope and scanning probe microscope that employ light (photons), electrons and a probe respectively. In this case, the light microscope is so called because it relies on visible light to produce the viewed image.
Unfortunately, majority of people under certain academic programs including teachers are not fully aware of some of the wide range of features and that come with the different light microscope types. This can be blamed on the increasing cost of light microscopes based on their versatility and quality. The following are four major types of such a microscope that perhaps you never knew exist.
Bright Field Microscope
This is the commonest type of light microscope that’s most likely to be found in many classrooms because it is relatively handy and affordable. Basically, light from a source is directed towards a lens located beneath the stage where you mount your specimen. This lens is referred to as a condenser. The condenser then focuses the light to the objective lens then through to the magnifying lens and finally to the eyepiece. Some of the organisms that can be viewed using bright field light microscope include paramecium. However, it is quite difficult to see living bacteria with such a microscope.
Dark Field Microscope
Although this type of a light microscope is rare, it plays a big role in some biological researches. It requires that before viewing the sample with this type of a microscope you must place an opaque disc at the bottom of the condenser lens. Unlike the case with bright field microscopes, the light doesn’t pass through the sample under study to but instead it comes from scattered particles included in the specimen. Ideally, it is very easy to convert bright field microscopes into a dark field microscope by simply fitting opaque discs beneath the condenser lens. Also, you have to modify your specimen by including some recommended light scattering particles.
Phase Contrast Microscope
According to a recent research, Phase contrast microscopes are considered as the best types of compound microscopes which are typically used to carry out an examination of biological tissue. Basically, this type of a light microscope alter the light’s wavelength to increase the view of the specimen under study. For instance, it is equipped with a phase plate that increase the wavelength of light by about half a wavelength. As a result, the specimen being viewed appears like a dark object, nonetheless extremely clear when viewed.
Nomarski Microscopes have emerged as the most technologically advanced type of a light microscope with the ability to give a 3 dimensional image of the specimen unlike the one you would obtain by using the above mentioned types. It operates by passing light via a polarizer that produces light waves vibrating in single planes. The resultant light is then passed through a prism that before passing it through the condenser.