Microscope parts:

The basic design of the microscope has not changed that much over time. They have evolved, but the basic concept is still the same. There are several key parts that many types of microscopes have in common. All of the parts of a microscope must function properly for the microscope to work well. If one part is substandard, it can render the microscope useless. The major parts of a microscope are the lenses, the arm, the tube, the illuminator, the stage, and the adjustment knobs.
There are two kinds of lenses on a microscope. The eyepiece lens, also known as the ocular lens is at the top of the microscope. This is the part that people look through. The ocular lens is not adjustable on most models. The objective lens provides much of the microscope’s magnification. A microscope usually has a few different objective lenses that vary in strength. The objective lenses are contained on a circular part placed between the eyepiece and the stage. Different objective lenses are chosen based on their strength. When someone wants to use a different strength of objective lens, they turn the circular disk to put another lens over the stage.
Other than the lenses, the other parts of a microscope are the tube, the arm, the stage, the illuminator and the adjustment knobs. The tube connects the ocular lens and the objective lens. People look through the ocular lens and tube and see out of the objective lens at the bottom. The arm connects the lenses and the stage. It protrudes to the side and provides a handle to carry the microscope as well. The stage is where the object is placed for examination. Stage clamps secure the microscope slides to the stage. The microscope slides contain specimens such as blood or other liquids. The illuminator is below the stage. This part provides light to make the specimen easier to see. The illuminator is either an actual light or a mirror.
Most microscopes feature two adjustment knobs to help focus the lenses. The coarse adjustment knob is the larger of the two and brings the lens and the stage closer together. The fine adjustment knob is smaller and is used after the coarse adjustment knob to provide any small adjustments to bring the item into sharp focus.
These parts of a microscope are common to nearly all models. Some microscopes use slightly different parts. For example, electron microscopes use electron beams instead of illuminators

History:

Hans Janssen and Zacharias Janssen are held to be the inventors of the microscope, according to the recorded letters of the Dutch envoy, William Boreel. The invention was around the year 1595. Galileo Galilei developed a compound microscope using a convex and a concave lens in the year 1609. The formulation of Christian Huygens in the 17th century, the simple 2-lens ocular system with achromatic correction is popular even today. Anton van Leeuwenhoek popularized the functionality of the instrument among the biologists and the credibility, the "Father of Microscopy" is generally awarded to him. Leeuwenhoek made his famous single lens microscope in the year 1673.
During the beginning years of invention, the microscope was a toy in the rich houses. The first significant discovery using microscopes was about the circulating blood system of the human body. It then led to many valuable discoveries for mankind. The steps such as the correction of spherical aberration, use of achromatic lenses etc were appreciated during the 1820's. August Kohler introduced the microscope lamp with filters in 1880. He also finalized the condenser position to provide the best image projection. The theory of the microscope was published by Ernst Abbe in 1873. In the same year, Ernst Leitz introduced the microscope with a revolving mount for 5 objectives. The oil immersion lens was used from the year 1878, and the apochromatic objective was introduced into microscopy by Ernst Abbe in1886.
The first commercial UV microscope was presented by Zeiss in 1904. In 1930, Fritz Zernike invented the phase contrast microscope, which helps to study transparent living things. The revolutionary TEM electron microscope of Ernst Ruska and Max Knoll was introduced in 1931 and the scanning electron microscope was evolved later in 1937. Yet another milestone in the history of microscopes is the scanning tunneling microscope invented in 1981 by Gerd Binnig and Heinrich Rohrer, which help to visualize the atomic level 3D structure of objects. The scanning laser confocal microscope was commercially available from 1983.