Optical microscopes and electrical microscopes have their own areas of application

Optical microscope: The objective lens is located near the object being observed and is the lens that achieves the first level of magnification. Several objectives with different magnifications are mounted on the nosepiece at the same time, and the rotation of the converter allows the objectives of different magnifications to enter the working optical path, and the magnification of the objective lens is usually 5 100x.

The eyepiece is a lens that is located near the human eye to achieve a second level of magnification, and the magnification of the lens is usually 5 to 20x.

Electron Microscope: At the top of the tube is an electron gun, and electrons are emitted from the tungsten hot cathode and focused by the first and second condensers. After the electron beam passes through the sample, it is imaged on the intermediate mirror by the objective lens, and then magnified step by step through the intermediate mirror and projection mirror, and imaged on the phosphor screen or photographic coherent plate.

The intermediate mirror mainly adjusts the excitation current, and the magnification can change continuously from dozens of times to hundreds of thousands of times.

And it's related to the diffraction of light, because visible light has a longer wavelength, so when you look at tiny things, the diffraction phenomenon is obviously as small as a micron, which is 200 nanometers, so you have to use a shorter wavelength (about a few hundredths of light) cathode rays, which are rays, which are electron microscopy"Light"The range is as small as nanometers.

Light microscopy can be used to observe living cells, such as mitochondria stained with Gennagreen or chloroplasts without staining. But it has a limited resolution (do you know the diffraction of light?). ), electrical microscope?

Electron microscope, there are many kinds, the structure is also very complex, but generally to the object of special treatment, can not see live, plus the aberration is difficult to eliminate, (it is with electromagnetic lens instead of optical lens), the resolution is also limited, in recent years, the resolution of the optical microscope can be made higher by fluorescence, I will not go into details, there is also a field microscope, "Feynman Lectures on Physics" is introduced, if you like physics, this book is quite good.

Commonly used microscopes include binocular continuous zoom stereo microscope, metallurgical microscope, polarizing microscope, ultraviolet fluorescence microscope, etc.

1. Binocular stereo microscope is widely used in the field of biology and medicine, and is widely used in sectioning and microsurgery; It is used in industry for the observation, assembly, and inspection of small parts and integrated circuits.

2. The metallographic microscope is a microscope specially used to observe the metallographic structure of opaque objects such as metals and minerals.

3. Television microscopes and charge coupler microscopes are microscopes with TV camera targets or charge couplers as receiving elements.

4. A scanning microscope is a microscope in which the imaging beam can scan relative to the object surface.

Summary. Optical microscope uses optical principles to form clear images, which has the advantages of low cost, simple operation, moderate resolution, and no need for vacuum. Compared to electron microscopes, optical microscopes are easy to use and do not require complex sample preparation, handling techniques, and equipment maintenance.

At the same time, optical microscopes are suitable for the study of biology, medicine, materials science and other disciplines, and can observe living organisms, soft tissues, and samples that do not require conductivity. In addition, the optical microscope can be used with different imaging techniques, such as fluorescence microscope, speed microscope, etc., to further improve the performance of resolution and sensitivity, and broaden the scope of analysis.

Optical microscope uses optical principles to form clear images, which has the advantages of low cost, simple operation, moderate resolution, and no need for vacuum. Compared to electron microscopes, optical microscopes are easy to use and do not require complex sample preparation, manipulation and equipment maintenance. At the same time, optical microscopes are suitable for the study of biology, medicine, materials science and other disciplines, and can observe living organisms, soft tissues, and samples that do not require conductivity.

In addition, the optical microscope can be used with different imaging techniques, such as fluorescence microscope, spread-velocity microscope, etc., to further improve the resolution, sensitivity and other performance, and broaden the scope of analysis.

Extended Information: Optical microscopy has a significant disadvantage due to its lower resolution than electron microscopy. At present, with the continuous development of optical principles and imaging technologies, people have gradually overcome this difficulty and obtained super-resolution optical microscopes.

This microscope can be used to study biomolecules, cells, nanomaterials, slide bridges, macromaterials, and other fields.

The optical aberration microscope is an optical instrument that uses optical principles to magnify and image tiny objects that cannot be distinguished by the naked eye, so that people can extract microstructural information. After more than 50 years of development, electron microscope has become an indispensable and important tool in modern science and technology. The electron microscope consists of three parts: a lens tube, a vacuum device and a power cabinet.

Answer]: An optical microscope is an optical instrument that uses visible light as an illumination source to form a magnified image of a tiny object; On the other hand, an electron microscope is a large-scale instrument that uses an electron beam as an illumination source, transmits or reflects the sample through electron flow and multi-stage magnification of the electromagnetic lens and images it on the fluorescent condosing screen. They differ in that:

The illumination source is different: the illumination source of the light microscope is visible light, and the illumination source of the electron microscope is the electron beam; Since the wavelength of the electron beam is shorter than that of the light wavelength, the magnification and resolution of the electron microscope are significantly higher than that of the light microscope.

The lenses are different: the light mirror is a glass lens; The electron microscope is an electromagnetic lens.

The resolution and effective magnification ability are different: the resolution of the light mirror is about right, and the magnification is 1000 times; The resolution of the electron microscope can be reached, and the magnification is 106x.

Vacuum requirements are different: light mirrors do not require vacuum; Electron microscopy requires vacuum.

The imaging principle is different: the light mirror uses the absorption of light by the sample to form light and dark contrast and color change imaging; Electron microscopy, on the other hand, uses the scattering and transmission of electrons from the sample to form a contrast imaging of light and dark.

The preparation techniques of biological samples are different: the preparation techniques of light microscope samples are relatively simple, usually including tissue sections, fine ridge cell smears, group pressure tablets and cell drops; However, the preparation of electron microscope samples is more complex, the technical difficulty and cost are high, and special reagents and operations are required in the process of material collection, fixation, dehydration and embedding, as well as the preparation of ultra-thin sections.

The function of the microscope is to study the structure and specific internal characteristics of the object by magnifying the specific shape of the object, which is mainly used in the physical, biological and medical aspects. Microscopes have optical microscopes and electron microscopes, what is the difference between the two? Let's take a look!

There are five main differences between electron microscopes and optical microscopes:

1.Optical microscopes (hereinafter referred to as light microscopes) use visible light as a light source, while electron microscopes (hereinafter referred to as electron microscopes) use high-precision short-wavelength electron coarse beams instead of visible light.

2.Depending on the magnification, the light microscope can generally magnify up to 2000 times, and the electron microscope can be as high as hundreds of thousands of times.

3.Optical lenses are used for focusing lenses for light mirrors, while electromagnetic lenses are used for electron microscopes.

4.The light microscope can only observe the surface microstructure, and the electron microscope can obtain the crystal structure, microstructure, chemical composition, and the distribution of electron filial piety stools.

5.The imaging system is different. Light microscopy can only see cells and some organelles, such as mitochondria and chloroplasts, but only their presence, not the specific structure of the organelles (such as the basal grains of chloroplasts, the ridges of mitochondria).

Electron microscopes can see the fine structure of organelles, even the smallest organisms like viruses, and even large molecules such as proteins.

The biggest difference between an optical microscope and an electron microscope is that the wavelengths used are different, the former uses visible light, the resolution is up to micron, the maximum effective magnification can only be about 1600 times, and the corresponding depth of field is also very small (micron). The latter uses electrons, which, according to the theory of wavelength of matter, can achieve a resolution of electron microscopes in the nanometer range, which is thousands of times higher than that of optical microscopes, under the acceleration of voltages ranging from tens of kilovolts to hundreds of kilovolts.

When the magnification of the electron microscope is small, its depth of field is large, and it can shoot a very three-dimensional **.

1. Optics tens of thousands to hundreds of thousands. Electronics, millions of dollars or more.

2. Optics is the use of light, and electron microscope is the use of electron beams to see things.

So it must be the magnification of the electron microscope.

Hope it helps you in your studies.

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Mitochondria, endoplasmic reticulum, centrosomes, chloroplasts, Golgi apparatus, ribosomes and other organelles can be seen under the electron microscope, and plastids and vacuoles can be seen under the light microscope.

Organelles are usually divided into: mitochondria; Chloroplast; Endoplasmic reticulum; Golgi apparatus; lysosomes; Vacuoles, ribosomes, centrosomes. Among them, chloroplasts are only found in plant cells, vacuoles are only found in plant cells and lower animals, and centrosomes are only found in lower plant cells and animal cells.

At the secondary level, the nucleus is not recognized as an organelle, whereas at the college level, the nucleus is considered to be the largest and most important organelle in the cell.

In addition, in cells, cytosol accounts for about 55% of the total volume of cells, in which thousands of enzymes are present. Most intermediate metabolism, including glycolysis, gluconeogenesis, and the synthesis of sugars, fatty acids, nucleotides, and amino acids, takes place in the cytosol.

The cytoplasmic matrix is essentially a highly organized system at different levels, rather than a simple solution. However, the tangible structures within the cytoplasmic matrix are not visible under ordinary transmission electron microscopy.