1. Classification of microscopes
Scientifically, microscopes are divided into two categories: optical microscopes that work under visible light conditions and non-optical microscopes that work under invisible light (including electron rays). In practical work, people often name microscopes according to the performance and use of microscopes, and classify them according to the magnification, illumination mode, imaging form, structure, function and use of the microscope body.
(1) Classification by magnification
①Low magnification microscope: The total magnification is below 200 times. This microscope is light in weight, small in size and simple in structure, generally equipped with a 10x or 12.5x heliostat and a 10x or 16x objective. It is suitable for observing animal and plant specimens, such as tiny insects, seed germs, etc. It can also be used for plant protection, family education, etc.
②Universal microscope: a microscope with a total magnification of more than 200 times and less than 1000 times. This kind of microscope often adopts a straight cylindrical structure, and the precision is lower than that of the microscope. Generally equipped with 5x, 10x, 16x eyepiece and 4x, 10x, 40x (or 60x) objective. The general cooperation is less than 640 times, which is suitable for biological experiments, inspection and breeding in agriculture, forestry and animal husbandry. This model is cheap and high quality, and has a wide range of applications.
③High magnification microscope: The total magnification is about 1000~1600 times. This microscope often adopts the slanted eyepiece tube structure, which is exquisite in shape and high in precision. Sometimes to extend the function, it also comes with various accessories.
④ Ultra-high magnification microscope: the total magnification is more than 10,000 times, and some electron microscopes have reached 1 million times. This microscope is used by specialized research departments to study viruses, molecular structure of substances, analyze crystals, etc.
(2) Classification according to the structure of the mirror body
① Straight tube microscope: Generally low magnification, popular type and high magnification type with low operation requirements all adopt this structure, which is characterized by economical benefits, convenient operation and portability. The disadvantage is that the observer is more difficult. If the lens barrel is tilted, the liquid material on the slice will flow, which will limit the observed object.
②Monocular oblique tube microscope: This microscope adds a prism in the eyepiece tube, so that the optical path is inclined at 45° to the vertical line, and the observer feels relaxed when using it without changing the horizontal position of the slice. Because natural light is generally used for lighting, the scope of use is limited.
③ Binocular oblique tube microscope: This microscope adds a group of light prisms after the refraction prism, and uses two eyepiece tubes to observe at the same time, which is suitable for the observer to work for a long time, and the eyes will not feel tired. Generally, high-power microscopes and microscopes for scientific research use this structure, and the distance between the binocular tubes can be adjusted according to the needs of the observer. The base of this kind of microscope is generally made into a box shape, and the interior is equipped with artificial light source illumination, which can provide various required illumination, provide conditions for the expansion of the microscope function and expand the scope of use, and is suitable for experiments, scientific research and other purposes.
④ Stereo microscope
⑤Inverted microscope: The observation object of this microscope is placed above the objective lens, and the objective lens is observed from the bottom up, that is, directly from the bottom of the petri dish or beaker, through the quartz glass at the bottom of the container, and is suitable for some special-purpose research. In addition, metallographic microscopes generally adopt this structure. Since the object to be observed is an opaque object, the inverted microscope should be equipped with a better epi-illumination light source and a photographic device.
(3) Classification according to Ming technology
①Brightfield microscope: Generally speaking, microscopes that use transmitted light to illuminate sliced specimens belong to brightfield microscopes.
②Dark field (dark field) microscope: Compared with bright field microscope, it is equipped with dark field condenser. In darkfield illumination, light illuminates the object to be observed along a specific angular direction without entering the microscope objective. What enters the objective is light that is diffusely reflected or diffracted by the specimen. In this way, the field of view seen by the observer is dark, and the bright specimen image is set off against the background of the dark field.
③ Fluorescence microscope: It is a microscope that uses ultraviolet light to illuminate, and it requires a special light source and filter device that can provide ultraviolet light. When used, the ultraviolet light does not directly enter the observer's eyes, but excites the fluorescent substance in the specimen or the specimen stained by fluorescent infiltration. The observation effect is similar to that of the dark field microscope, which shows the bright fluorescence image of the specimen in the dark background. For biological science research.
④Infrared microscope: Infrared light has a large penetrating ability, and different substances have different degrees of absorption of infrared light. Using this characteristic, a microscope is made to observe the object under the irradiation of infrared light, which is an infrared microscope. It is equipped with an infrared light source, which can transmit and observe some opaque objects, such as infrared light with a wavelength greater than 1.12X10-6m, which can penetrate single crystal silicon. Infrared light can also perform epi-observation on substances with different absorption degrees, which is a kind of microscope used for scientific research.
