One of the distinct features of an inverted microscope is that it is upside down compared to a conventional microscope. The light source and condenser are on the top above the stage pointing down. The objectives and turret are below the stage pointing up. The only things that are typical are the specimen as dictated by the laws of gravity is placed on top of the stage and the binocular or trinocular tube is not upside down but in the standard position pointing at a conventional viewing angle. As a result, one is looking up through the bottom of whatever is holding the specimen and is sitting on the stage rather than looking at the specimen from the top, typically through a cover glass, as on a conventional microscope. Inverted microscopes are useful for observing living cells or organisms at the bottom of a large container flask under more natural conditions than on a glass slide, as in the case with a conventional microscope. An inverted microscope is adapted so that a specimen thereonlike cells can be irradiated by a laser beam. The laser beam is guided from a laser source by a series of adjustably movable reflectors which introduces it to the microscope optical pathway at a parallel beam region thereof, and tyhrought he object lens of the microscope. A point to be irradiated can be selected by moving the reflectors which maybe galvanometrically-movable. The laser beam can be focused together with the microscope image.

The movable reflectors are kept within 200mm behind the objective lens principal lane to ensure that the laser can be applied all over the microscope viewing field. Paragraph2: The vital benefit of light microscopy over electron microscopy is the ability to observe living organisms and tissue. The various types of electron microscopes require that the specimen be thoroughly prepared which may include coating it with gold and placed in a vacuum chamber for observation. Obviously, whatever life is in the specimen does not survive this process. Light microscopes permit one to observe a live microorganism such as a protozoan as it goes about its diverse life functions. While an electron microscope has extensively greater magnification and resolution than a light microscope and some types can produce spectacular 3D images, it only produces a snapshot in time of a dead subject. The conventional light microscope requires that the specimen be placed on a glass slide, typically under a cover slip. This usually means removing a small sample from the culture and placing it in the artificial environment created by the slide and cover slip.

The temperature and oxygen content of the sample may change quickly from that of the culture as a result. Further, the organisms will be under increased pressure and in an unnaturally limited space as a result of the cover slip. Also, the sample will quickly dry out unless repeatedly replenished with water. The loss of water by evaporation and the periodic adding of water may change the salinity of the sample frequently. These changes impose severe stress on microorganisms that can affect their behavior and/or kill them in a short time. Several partial solutions to these problems include making a tiny chamber on the slide or using a slide with a well or chamber built in and sealing it to avoid evaporation. While this keeps the sample from drying out quickly, the inability of the sample to exchange gasses with the air means that within a day, a few days or a week, the organisms will die. Another partial solution is to use the hanging drop technique in deep well slide which prevents pressure and reduces confinement but again is fairly temporary. Therefore, observations through a standard microscope are also limited in time. Its images are not the frozen image of an electron microscope but neither can it easily allow study over long duration (it is true that another technique available is to use special reservoir slides with built-in water chambers that allow the specimen to remain active for long periods but this still requires specimen preparation and creates a relatively limited environment for the life on the slide. The inverted microscope allows observation of microorganisms in a large container under more natural conditions and by doing so, it extends the advantage of the light microscope. Because of its configuration, You can place a complete culture or large sample in a relatively large container such as a petri dish and look at the entire contents of the container under more natural and less stressed conditions. Such a sample may sustain life over a much longer period