Essentially, a compound microscope consists of structural and optical components. However, within these two basic systems, there are some essential components that every microscopist should know and understand.
These key microscope parts are illustrated and explained below. Base of the microscope supports the microscope and houses the illuminator. Arm connects to the base and supports the microscope head. It is also used to carry the microscope. When carrying a compound microscope always take care to lift it by both the arm and base, simultaneously. Eyepiece or Ocular is what you look through at the top of the microscope.
Eyepiece Tube holds the eyepieces in place above the objective lens. Objective Lenses are the primary optical lenses on a microscope. Nosepiece houses the objectives. By that time, Romans had invented glass and began testing it for its uses in magnifying what can be seen through it. They started experimenting with different shapes and sizes of glasses to figure out the best way to magnify something by looking through it including how it could direct the sun's rays to light objects on fire.
They called these lenses "magnifiers" or "burning glasses. Near the end of the 13th century, people started creating glasses using lenses. In , two Dutch men, Zaccharias Janssen and his father Hans, performed experiments using the lenses. They discovered that placing the lenses one on top of the other in a tube could enlarge an image at much greater magnification than a single lens could achieve, and Zaccharias soon invented the microscope.
This similarity to the objective lens system of microscopes shows how far back the idea of using lenses as a system goes. The Janssen microscope used a brass tripod about two and a half feet long. Janssen fashioned the primary brass tube that the microscope used at around an inch or half of an inch in radius. The brass tube had discs at the base as well as at each end. Other microscope designs began to arise by scientists and engineers. Some of them used a system of a large tube that housed two other tubes that slid into them.
These handmade tubes would magnify objects and serve as the basis for the design of modern microscopes. These microscopes weren't usable for scientists just yet, though. They would magnify images about nine times while leaving the images they created difficult to see. Years later, by , astronomer Galileo Galilei was studying the physics of light and how it would interact with matter in ways that would prove beneficial to the microscope and telescope.
He also added a device to focus the image to his own microscope. Dutch scientist Antonie Philips van Leeuwenhoek used a single-lens microscope in when he would use small glass spheres to become the first human to observe bacteria directly, becoming known as "the father of microbiology. When he looked at a drop of water through the lens of the sphere, he saw the bacteria floating around in the water. He would go on to make discoveries in plant anatomy, discover blood cells and make hundreds of microscopes with new ways of magnifying.
One such microscope was able to use magnification at times using a single lens with a double-convex magnifier system. The coming centuries brought more improvements to microscope technology. The high power objective lenses are retractable ie 40xr. This means that if they hit a slide, the end of the lens will push in spring loaded thereby protecting the lens and the slide.
All quality microscopes have achromatic, parcentered, parfocal lenses. Rack Stop: This is an adjustment that determines how close the objective lens can get to the slide. It is set at the factory and keeps students from cranking the high power objective lens down into the slide and breaking things.
Condenser Lens: The purpose of the condenser lens is to focus the light onto the specimen. Condenser lenses are most useful at the highest powers x and above. Microscopes with a stage condenser lens render a sharper image than those with no lens at x.
If your microscope has a maximum power of x, you will get the maximum benefit by using a condenser lenses rated at 0. A big advantage to a stage mounted lens is that there is one less focusing item to deal with. If you go to x then you should have a focusable condenser lens with an N. Most x microscopes use 1. On most compound microscopes the ocular lens offers either 10x or 15x levels of magnification.
The objective lens of a compound microscope sometimes referred to as a light or optical microscope typically offers a significantly higher level of magnification. Usually this lens offers users anywhere from 40x to x magnification.
The advantage of using two convex lenses when viewing a specimen is that the objective and ocular lenses work together to enlarge an image more than a single lens could. An additional advantage to using two lenses and why compound microscopes are so popular is that they place the enlarged image farther away from the human eye.
This makes the image easier to view and examine.
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