This section provides an overview for electron microscopes as well as their applications and principles. Also, please take a look at the list of 7 electron microscope manufacturers and their company rankings.
Table of Contents
An electron microscope is a microscope that observes a sample by irradiating it with an electron beam. Due to the extremely short wavelength of the electron beam, it is possible to visualize ultra-fine structures that cannot be observed with an optical microscope. There are two main types of electron microscopes: those that output the transmittance of the electron beam as an image and those that image the signal produced by the interaction between the electron beam and the sample.
Most electron microscopes sold as products are optimized for industrial materials and for the observation of biological specimens.
In the industrial field, electron microscopes are used to analyze the fractured surface of a damaged metal part to determine the cause of the damage or to observe the surface of a processed part to check its quality. It is also used to examine the instrumental properties of macromolecular polymers by observing their networks and to evaluate the presence of impurities. In the life sciences field, it is used to visualize the microstructure of intracellular organelles and to map the connections between neurons by observing intricately entangled nerve cells. The 2017 Nobel Prize in Chemistry was awarded to the developers of cryo-electron microscopy for its application in analyzing the structures of biomolecular samples.
The elements that make up an electron microscope are a radiation source, lens, and detector, a configuration that is similar to that of an optical microscope when viewed in words alone. However, each of these elements is very different in principle from that of an optical microscope.
First of all, electron beams are immediately attenuated and annihilated when they collide with molecules and other substances in the air. Therefore, electron beams must be generated and transmitted in a vacuum.
Second, since glass lenses such as those used in general optical systems are transparent, magnetic lenses that converge by applying a magnetic field must be used to refract the electron beams.
A characteristic of such lenses is that they have large optical aberrations, and to improve this, they are designed with a small numerical aperture. This allows the electron microscope to have a deep depth of focus and to observe three-dimensional objects with depth.
Standard electron microscopes are classified into two categories:
In this method, an electron beam is transmitted through a sample, and contrast is obtained based on its attenuation. In order for the electron beam to penetrate the sample, the thickness of the sample must be adjusted to be very thin. The strength of the electron beam is called the acceleration voltage, and at an acceleration voltage of 300 kV, the wavelength is 0.00197 nm, which is extremely short. The resolution is 0.1 nm, which is on the order of the size of the original material. This is 2,000 times higher than the resolution of an optical microscope. Since transmission electron microscopes observe electrons transmitted through the interior of a sample, they are excellent for observing the internal structure of a sample, such as the crystal structure in a very small area.
When materials are irradiated with electron beams in a vacuum, secondary electrons, reflected electrons, and characteristic X-rays are emitted. Scanning electron microscope images are formed from secondary electrons and reflected electron signals by scanning spatially focused electron beams. Secondary electrons are generated from near the surface of the specimen, so the secondary electron images are suited for viewing microscopic irregularities in the specimen. The number of reflected electrons depends on the composition of the sample (atomic number, crystal orientation, etc.), making the reflected electron image suitable for evaluating the compositional distribution of the sample surface.
When an electron beam strikes a sample, the atoms that make up the surface are excited and emit electrons. Other emissions include reflected electrons and characteristic X-rays, which are called secondary electrons and are obtained by point-scanning the intensity of the emitted secondary electrons.
Electron microscopes have highly high resolution compared to ordinary optical microscopes, making it possible to observe, for example, the minute tissue structures of cells and metal crystals on the order of atomic size.
Taking cells as an example, optical microscopes cannot observe in detail the minute structures in cells other than the nucleus, but electron microscopes can. This makes it possible to investigate in detail the function of enzymes in the cell, reactions of cellular structures, and various other functions.
*Including some distributors, etc.
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Ranking as of March 2023 in United States of America
Derivation MethodRank | Company | Click Share |
---|---|---|
1 | LG Chem | 30.4% |
2 | TEIJIN LIMITED | 30.4% |
3 | Chi Mei Corp. | 26.1% |
4 | SAMYANG CORPORATION | 13% |
Ranking as of March 2023 Globally
Derivation MethodRank | Company | Click Share |
---|---|---|
1 | LG Chem | 28% |
2 | TEIJIN LIMITED | 28% |
3 | Chi Mei Corp. | 24% |
4 | SAMYANG CORPORATION | 12% |
5 | ZEISS Microscopy | 8% |
Derivation Method
The ranking is calculated based on the click share within the electron microscope page as of March 2023. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
Newly Established Company
Company with a History
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