When a magnifying glass isn't enough, you need a microscope. There are different types of microscopes for different uses. There are high-powered microscopes and low-powered ones. High-powered microscopes are also known as compound microscopes or biological microscopes. Low-powered microscopes are also known as stereo microscopes or dissecting microscopes. Before you start looking at microscopes, you must first decide what you want to study or explore. That single answer will help you find out what microscope you really need.
What is a Microscope?
A microscope is an optical instrument that utilises lenses to produce magnified images of objects. It is used by many professionals, students, kids and hobbyists, for many different purposes. A microscope usually has a light source (mirror or lamp) for better and clearer viewing. Cheaper, discount-store microscopes tend to have no lighting or a mirror. The magnification of a microscope varies, depending on its type and purpose. From blood cells and insects to circuit boards, there are limitless possibilities that you can see through a microscope.
Who Invented the Microscope?
There is no one exact person who developed the microscope. Based on historical records, several inventors experimented and came up with many theories and ideas which were actually different parts of the concept. In 1590, two Dutch spectacle makers, Zaccharias Janssen and his son Hans, developed a very basic 10x - 30x microscope. In 1609 however, Gallileo improved on the concept by adding a focusing device. In the early 1670s, Anton van Leeuwenhoek worked on the basic optical instruments, from crude concepts to advanced practical microscopes. Anton van Leeuwenhoek is considered the father of microscopes because of what he contributed to the development of microscopes. He taught himself new methods to grind and polish small lenses which magnified up to 270x. In 1674, Anton was the very first man to see and described bacteria, yeast, plants and life in a drop of water.
A Compound Microscope (Biological Microscope) uses the power of its lenses and light to enlarge what's being viewed.
Compound refers to the fact that in order to enlarge an image, a single light path passes through a series of lenses in a line where each lens magnifies the image over the previous one. In other words, one light path with multiple lenses equals a compound microscope.
The compound microscope is what many refer to as a high-power microscope. The magnification (power) can have a range from about 40x to 1000x and some can go up to 1600x or 2000x. Most users operate between 400x and 600x magnification.
The objective lens usually consists of three or four lenses (sometimes even five) on a rotating nosepiece (turret) so that the power can be changed. The image produced at the eye is two-dimensional (2D) and usually reversed and upside down. The most used light method is trans-illumination (light projected from below to pass through the specimen).
A Stereo Microscope (Dissecting Microscope) has two optical paths at slightly different angles allowing three-dimensional viewing. Stereo microscopes magnify at low power, typically between 10X and 200X, generally below 100x.
There are two separate light paths (as opposed to a single light path in a compound microscope) which produce a true stereo, three-dimensional (3D) image of the specimen or object. Within the objective lens, you will find two lenses (one for each path of light) side-by-side. The optical design parameters of a stereo microscope limit its 3-D effects to low powers only.
This type of microscope is generally very affordable. Uses for this type of microscope include looking at surfaces, microsurgery, circuit boards, other electronic components and watch making.
Stereo microscopes allow students to observe plant photosynthesis in action.
Digital Microscopes are essentially a combination of a microscope and a digital camera, created to be used with computers. They are often connected via USB or HDMI so that the magnified image can be viewed on a computer screen or monitor. Digital Microscopes are normally compatible with image capturing software so you can save images or record videos.
Some Digital Microscopes have LCD screens inbuilt.
You can email your images, post them online or keep them as a record. Digital Microscopes are great for schools and hobbyists.
There are also Handheld Digital Microscopes, which act as miniature stereo microscopes that use new technology to combine a camera and illuminator into a single unit. You use a PC or laptop computer to view and image.
Other Types of Microscopes
These are usually advanced and expensive type microscopes made for specific usages, mainly in advanced medical and research. There
are many, many types but some of the more popular types are listed below.
- Phase Contrast – This is a microscope that uses the differences in the phase of light transmitted or reflected by a specimen to form distinct, contrasting images of different parts of the specimen.
- Polarizing – A microscope in which the object viewed is illuminated by polarised light to analyse the content and make-up of organic or inorganic material such as crystals, chemical microscopy and optical mineralogy.
- Fluorescence – These microscopes use an illumination method to locate fluorescently tagged material (protein, enzymes, genes, etc.) by exciting the specimen with one wavelength of light in hopes that the fluorescence will appear by emitting light at a different wavelength.
- Metallurgical – A microscope that is used for the identification, inspection and analysis of different metals and alloys.
- Electron Beam – These microscopes typically cost upwards of $100,000. They use a beam of highly energetic electrons (instead of light) to examine objects on a very fine scale. This allows the microscope to surpass the resolution limits of optical microscopes and can magnify specimens up to 250,000x or more. Users can examine the topography of a specimen, its morphology, composition, etc.
Most professional microscopes come with its power adapter and a dust cover. There are many accessories that you may need to actually use your microscope properly, and even some accessories that will give you more features to get more out of your microscope. After all, you don't want to be paying $1000 for a microscope and not know how to use it to its maximum capacity.