Example Welcomw Wddress

Principles of Operation of the microscope












optical microscope


Observation of a thin section of cork

components of an optical microscope ancient


microscopes are instruments used to produce enlarged visual images of objects too small to be observed with the naked eye .
It must fulfill three basic functions: 1
produce a magnified image of the preparation,
2 separate 3
details make this visible to the eye.
The full name of the microscope is " optical microscope", which is useful to distinguish it from simple microscope known as a magnifying glass. Essentially
the optical microscope consists of two converging lenses and convex.
These two lenses are in 'target and in' eye, placed at each end of a tube called the body tube of the microscope.
The goal, placed near the object to be observed real produces an image, magnified and inverted, which in turn is viewed through the eyepiece, it receives this image in its own fire and turns in the final image, which is virtual, inverted and larger than the real one.

So what we did not observe is the real image of the preparation, but this' last much magnified by the eyepiece.

A simple goal has two focal planes that are defined by the geometry of the lens and the ratio between the lens and the image focus. Light rays passing from the lens plane intersect and merge focal rays leaving the lens plane intersect those from the main. the focal length of a lens is defined as the distance between the aircraft and the main focal plane.

To understand what is happening is also important to understand what happens when our eyes see the image.

.

They are able to distinguish the colors of the visible part of the spectrum : from purple to blue to yellow, orange, red, the eye can not perceive ultraviolet or infrared. It is also sensitive to changes in brightness or light intensity. So the image to be visible to the eye, must be submitted in color of the visible spectrum and certain degrees of intensity. That portion of the retina used for sensing color are the cells cone, the cells that detect changes in light, rod cells are . These cells are located on the retina at the back of the inside of the eye. Finally, the conventional distance of the lens from the eye is about 25 cm .

Authors: Massimo Gaggia, Giori Fabrizio, Kristian Sartori

Sources : http://micro.magnet.fsu.edu ; http://it.encarta.msn.com ;