Why can't electron microscopes replace optical microscopes?
Electron microscopes use the principle of electron optics, replacing light beams and optical lenses with electron beams and electron lenses, so that the fine structure of matter can be imaged at very high magnification. Although its resolving power is far better than that of optical microscopes, electron microscopes need to work under vacuum conditions, so it is difficult to observe living organisms, and the irradiation of electron beams will also cause radiation damage to biological samples, so they cannot completely replace optical microscopes. Microscopes, and their costs are different, and their suitable working ranges are also different. Hope my answer can be helpful to you.
The reasons why electron microscopes cannot completely replace optical microscopes are as follows:
1. An electron microscope is an optical microscope with the addition of CCD, display screen or computer and other accessories. It can only be said to be a video microscope. During the entire imaging process, the CCD replaces the human eye. Because in video imaging, electronic amplification is virtual amplification, and in terms of pixels, photosensitivity effects and other factors, it is too different from that of the human eye, so the effect is too different from that of a visual microscope;
2. There is another most important reason. CCD is a plane imaging, while the human eye, especially when observing with binoculars, will produce a strong three-dimensional sense. This is the reason why the depth of field effect between the two is too large;
3. Electron microscopes are mostly represented by electron scanning microscopes. The effect of this microscope is much better than that of ordinary optical microscopes. However, because it is expensive, it is rarely used in industry.
microscope observation range
Also called ultrastructure. Refers to various microstructures within cells that cannot be clearly distinguished when observed under an ordinary optical microscope. (The resolution limit of ordinary optical microscopes is about 0.2 microns. The thickness of cell membranes, endoplasmic reticulum membranes and nuclear membranes, and the diameters of ribosomes, microbodies, microtubules and microfilaments are all less than 0.2 microns. Therefore, observation with ordinary optical microscopes is Without these cellular structures, to observe various submicroscopic structures in cells, an electron microscope with higher resolution must be used.)
The fine structures with a diameter less than 0.2 microns that can be seen under an electron microscope are called submicroscopic structures.
