The working principle and development history of optical microscopes
Optical microscope (OM for short) is a Optical instrument that uses optical principles to magnify and image small objects that cannot be distinguished by human eyes, so that people can extract the information of microstructure.
As early as the first century BC, it was discovered that when observing small objects through spherical transparent objects, they can be magnified and imaged. Later, I gradually gained an understanding of the law that spherical glass surfaces can magnify and image objects. In 1590, eyewear manufacturers in the Netherlands and Italy had already created magnifying instruments similar to microscopes. Around 1610, Galileo of Italy and Kepler of Germany, while studying telescopes, changed the distance between the objective and eyepiece to obtain a reasonable optical path structure for microscopes. At that time, optical craftsmen were engaged in the manufacturing, promotion, and improvement of microscopes.
In the middle of the 17th century, Robert Hooke of England and Leeuwenhoek of the Netherlands made outstanding contributions to the development of microscopes. Around 1665, Hooke added coarse and micro focusing mechanisms, lighting systems, and workbenches for carrying specimen slides to the microscope. These components have been continuously improved and become the basic components of modern microscopes.
Between 1673 and 1677, Levin Hooke developed a single component magnifying glass type high-power microscope, of which nine have been preserved to this day. Hooke and Levin Hooke achieved outstanding achievements in the study of the microstructure of animal and plant organisms using self-made microscopes. In the 19th century, the emergence of high-quality achromatic immersion lenses greatly improved the ability of microscopes to observe fine structures. In 1827, Archie was the first to use immersion lenses. In the 1870s, German Abbe laid the classical theoretical foundation for microscopic imaging. These all promoted the rapid development of microscope manufacturing and microscopic observation technology, and provided powerful tools for biologists and medical scientists, including Koch and Pasteur, to discover bacteria and microorganisms in the latter half of the 19th century.
Along with the development of the structure of the microscope itself, microscopic observation technology is also constantly innovating: polarized microscopy emerged in 1850; In 1893, interference microscopy emerged; In 1935, Dutch physicist Zernike created phase contrast microscopy, for which he won the Nobel Prize in Physics in Physics in 1953.
The classical optical microscope is simply a combination of optical components and precision mechanical components, using the human eye as a receiver to observe the magnified image. Later, a photography device was added to the microscope, using photosensitive film as a receiver for recording and storage. In modern times, photoelectric components, television cameras, and charge couplers are commonly used as receivers for microscopes, which are combined with microcomputers to form a complete image information acquisition and processing system.
Optical lenses made of glass or other transparent materials with curved surfaces can magnify and image objects, and optical microscopes use this principle to magnify small objects to a size sufficient for the human eye to observe. Modern optical microscopes typically use two stages of magnification, each completed by an objective lens and an eyepiece. The observed object is located in front of the objective lens, and after being first magnified by the objective lens, it forms an inverted real image. Then, this real image is magnified by the objective lens in the second stage, forming an imaginary image. What the human eye sees is the imaginary image. The total magnification of a microscope is the product of the objective magnification and the eyepiece magnification. Magnification ratio refers to the magnification ratio of linear dimensions, not the area ratio.
