Microscopes can be classified into polarizing microscopes, optical microscopes, electron microscopes, and digital microscopes based on the principle of microscopy.
Polarizing microscope (Polarizing microscope) is used to study the so-called transparent and opaque anisotropic materials of a kind of microscope, in geology and other scientific and technological disciplines have important applications.
Any substance with birefringence can be distinguished clearly under a polarizing microscope, of course, these substances can also be used for observation by staining, but some of them can not be used, and must be utilized with a polarizing microscope.
The polarizing microscope is a necessary instrument for the study and identification of birefringent substances by using the polarizing property of light, and it can be used for single-polarized light observation, orthogonal polarized light observation, and conical light observation by a wide range of users.
Optical microscopes are usually composed of an optical part, an illumination part and a mechanical part. Undoubtedly, the optical part is the most critical, which consists of eyepieces and objective lenses. As early as 1590, the Dutch and Italian eyeglass makers had already built a magnifying instrument similar to the microscope.
There are many types of optical microscopes, mainly bright field microscope (ordinary optical microscope), dark field microscope, fluorescence microscope, phase-contrast microscope, laser scanning *** focusing microscope, polarizing microscope, differential interference difference microscope, inverted microscope.
The electron microscope has basic structural features similar to those of the optical microscope, but it has a much higher ability to magnify and resolve objects than the optical microscope, which uses a stream of electrons as a new light source to image objects.
Since 1938, Ruska invented the first transmission electron microscope to date, in addition to the transmission electron microscope's own performance continues to improve, but also developed a variety of other types of electron microscopes. Such as scanning electron microscopy, analytical electron microscopy, ultra-high voltage electron microscopy.
Combined with a variety of electron microscopy sample preparation techniques, samples can be multifaceted structure or structure-function relationship in-depth study. Microscopes are used to observe images of tiny objects. It is commonly used in biology, medicine and observation of tiny particles. Electron microscopes can magnify objects up to 2 million times.
Tabletop microscope, mainly refers to the traditional type of microscope, is pure optical magnification, its magnification is higher, the image quality is better, but the general volume is larger, not easy to move, more used in the laboratory, inconvenient to go out or on-site inspection.
Portable microscope, mainly developed in recent years out of the digital microscope and video microscope series of extension. And traditional optical magnification is different, handheld microscope are digital magnification, its general pursuit of portable, small and exquisite, easy to carry.
And some handheld microscopes have their own screen, can be detached from the computer host independent imaging, easy to operate, but also can be integrated with a number of digital features, such as support for photography, video, or image comparison, measurement and other functions.
Expanded Information
Optical microscope consists of eyepiece, objective lens, coarse focusing screw, fine focusing screw, platen clamp, aperture, shade, converter, reflector, stage, mirror arm, mirror tube, mirror base, concentrator, diaphragm. Microscope resolution: D = 0.61λ/N*sin (α/2), D: resolution, λ: wavelength of the light source, α: angle of the objective lens mouth (the specimen in the optical axis of the point of the objective lens mouth of the angle of tension)
Want to improve the resolution, you can through: 1, reduce λ, such as the use of ultraviolet as a source of light; 2, increase N, for example, put in the cedar oil; 3, increase the α, that is, as far as possible, make the lower the distance between the objective lens and the specimen.
References Baidu Encyclopedia - Microscope