Simple microscope

Simple microscope of Leeuwenhoek. The sample was placed on the tip of the screw, in front of the single lens, which highlights the smallness of its diameter.

A simple microscope is one that uses a single lens to magnify the images of the observed objects. It is the most basic microscope. The most classic example is the magnifying glass.
The standard light microscope, called a compound microscope, uses two aligned lens systems, the objective and the eyepiece.

History

• 1267 - Roger Bacon explains the principles of the lens and proposes the idea of telescope and microscope.
• 1590 - Dutch show mounters Hans Jansen and his son Zacharias Jansen are claimed to have invented a microscope composed of later writers (Pierre Borel 1620-1671 or 1628–1689 and Willem Boreel 1591–1668)
• 1609 - Galileo Galilei develops occhiolino o microscope composed with a convex lens and a concave.
• 1612 - Galileo presents the occhiolino to the king of Poland Segismund III.
• 1619 - Cornelius Drebbel (1572–1633) presents in London a microscope consisting of two convex lenses..
• ca.1622 - Drebbel presents his invention in Rome.
• 1624 - Galileo presents its occhiolino to Prince Federico Cesi, founder of the Academy of the Linces (Accademia dei Lincei).
• 1625 - Giovanni Faber de Bamberg (1574-1629) of the Lithuanians coin the word microscope by analogy with telescope.
• 1665 - Robert Hooke publishes Micrographia, a collection of biological micrographs and coins the word cell (cell) for the structures you discover in a cork bark.
• 1674 - Anton van Leeuwenhoek improves a microscope and invents the Simple microscope to see biological specimens.
• 1863 - Henry Clifton Sorby develops a metallurgical microscope to observe the meteorite structure.
• 1860 - Ernst Abbe discovers the relationship of Abbe breasts, a great advance in the design of the microscope, which until then was largely based on the essay and error. The company ofCarl Zeiss exploded this discovery and became the dominant microscope manufacturer of its time.

Over five hundred years ago, simple glass magnifying glasses were developed. These were convex lenses (thicker in the center than the periphery). The sample or object could then be brought into focus by the use of the magnifying glass placed between the object and the eye. These "simple microscopes" they could spread the image on the retina by magnification by increasing the visual angle on the retina.

Optical diagram of a simple microscope. It is observed that the virtual image created by the lens is greater than the object of study

The object to be observed is placed between the focus and the surface of the lens, which determines the formation of a virtual image, straight and greater the greater the dioptric power of the lens and the further away the near point of sharp vision of the subject.

The magnification obtained with these microscopes is low, due to the fact that the wavelength of visible light imposes limitations on it.

The Dutchman Anton van Leeuwenhoek is credited with bringing the microscope to the attention of biologists, even though simple magnifying glasses were already being produced in the 16th century. Leeuwenhoek built very efficient microscopes based on a single lens. His observations were famous enough to receive numerous visitors such as Queen Mary II of England (1662-1694), Peter the Great () or Frederick I of Prussia (), as well as philosophers and scholars, doctors and ecclesiastical. Van Leeuwenhoek performs numerous demonstrations before them: he showed Peter the Great the blood circulation in the tail of an eel.

The microscope seen in the photo was built around 1668 and is 10 cm long; these simple single-lens microscopes produced magnification up to 275 times (275x) and had a resolving power of 1.4 μm; they did not suffer from the aberrations that limited the efficiency of early compound microscopes, such as those used by Robert Hooke. With them Leeuwenhoek was even able to describe for the first time free-living and parasitic microscopic protists, sperm cells, blood cells, microscopic nematodes, rotifers and even bacteria.

It took about 150 years of development before compound microscope optics were able to provide the same image quality as Van Leeuwenhoek's simple microscopes, due to difficulties in the multiple lenses it used.