Today,Shangguang Instruments will introduce you to the history of the microscope.Why was the microscope invented?What is its purpose?Let’s explore these questions and delve into the development of the microscope!

　　As early as the 1st century BCE,people discovered that small objects could be magnified and imaged when viewed through spherical transparent materials.Gradually,an understanding of how spherical glass surfaces could magnify objects emerged.In 1590,eyeglass makers in the Netherlands and Italy had already produced magnifying instruments resembling microscopes.Around 1610,Galileo in Italy and Kepler in Germany,while studying telescopes,adjusted the distance between the objective lens and the eyepiece,resulting in a rational optical path structure for microscopes.Subsequently,optical craftsmen of the time devoted themselves to the manufacture,improvement,and promotion of microscopes.

　　In the mid?17th century,Robert Hooke of England and Antonie van Leeuwenhoek of the Netherlands made outstanding contributions to the development of the microscope.Around 1665,Hooke added coarse and fine focusing mechanisms,an illumination system,and a stage to hold specimen slides to the microscope.These components,continuously refined,became the fundamental parts of the modern microscope.

　　Between 1673 and 1677,Leeuwenhoek constructed high?power microscopes using single?element magnifying lenses;nine of them survive to this day.Using their homemade microscopes,Hooke and Leeuwenhoek achieved remarkable results in the study of the microscopic structures of animal and plant tissues.In the 19th century,the advent of high?quality achromatic immersion objectives greatly enhanced the microscope’s ability to resolve fine details.

　　In 1827,Amici was the first to use an immersion objective.In the 1870s,the German Ernst Abbe laid the classical theoretical foundation for microscope imaging.These advances spurred rapid progress in microscope manufacturing and microscopic observation techniques,providing powerful tools for biologists and medical scientists such as Koch and Pasteur in the latter half of the 19th century to discover bacteria and microorganisms.

　　Concurrent with the structural evolution of the microscope itself,microscopic observation techniques also saw continuous innovation:polarizing microscopy emerged in 1850;interference microscopy in 1893;and in 1935,the Dutch physicist Frits Zernike invented phase?contrast microscopy,for which he received the Nobel Prize in Physics in 1953.

　　The classical optical microscope was simply a combination of optical elements and precision mechanical components,with the human eye serving as the receiver to observe the magnified image.Later,photographic devices were added,using photosensitive film as a recordable and storable receiver.Today,photoelectric elements,television camera tubes,charge?coupled devices(CCDs),and the like are commonly used as microscope receivers,which,coupled with microcomputers,form complete image information acquisition and processing systems.

　　Optical lenses made of glass or other transparent materials with curved surfaces can magnify and image objects.The optical microscope exploits this principle to enlarge minute objects to a size perceptible to the human eye.Modern optical microscopes typically use two stages of magnification,accomplished by the objective lens and the eyepiece respectively.The specimen is placed in front of the objective lens,which produces a first?stage magnification as an inverted real image.This real image is then further magnified by the eyepiece to produce a virtual image,which is what the eye sees.The total magnification of the microscope is the product of the objective lens magnification and the eyepiece magnification.Magnification refers to the ratio of linear dimensions,not area.