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 which utilise a lens or lenses to produce magnified images of objects. It is used by many professional, students, kids, hobbyists, for many different purposes. A microscope usually has a light source (mirror or lamp) for better and clearer vieweing. Cheaper, discount store microscopes tend to have no lighting or a mirror. The power of magnifications vary, depending on the type and purpose of the telescope. There are so many things that you can see through a telescope from blood cells, insects to circuit boards.
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 microscope. Anton van Leeuwenhoek is considered father of microscopes because of his contribution. He taught himself new methods for grinding and polishing 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.
Compound microscope or 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 (2-D) and usually reversed and upside down. The most used light method is trans-illumination (light projected from below to pass through the specimen).
The Stereo microscope, also called a 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 (3-D) 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 micrsocope 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 microscope and digital camera, created to be used with computers. Connect it to a computer via USB cable and the magnified image can be viewed on the computer screen. Some digital microscopes come with image capturing software so you can save the images or record videos.
You can email your images, post them online or keep them as a record. Digital microscopes are great for schools and hobbyists.
There is also, Handheld Digital Microscope, it uses new technology for a miniature camera and illuminator in one 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 polarized light for typically analyzing the content and make-up of organic or inorganic material like crystals, chemical microscopy, and optical mineralogy. 9
- Fluorescence – These microscopes use an illumination method that is used to locate fluorescently tagged material (protein, enzyme, genes) by exciting the specimen with one wavelength of light in hopes that the fluorescence will appear by emitting a light at a different wavelength. Metallurgical – A microscope that is used for identification, inspection, and analysis of different metals and alloys.
- Electron Beam – These microscopes typically cost more than $ 100,000 and sometimes much more and 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 the power cable and a dust cover and that's it. 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.