Pictures will be distorted when enlarged, but microscope imaging will not. What is the principle of microscope magnification?

When we want to observe a detail of a picture in detail, we will enlarge the picture. However, there is a limit to the magnification ratio. Once this limit is exceeded, the picture will become blurred and distorted.

However, even if the image is magnified, the magnified image under the microscope will not be blurred or distorted. Even if the object is magnified thousands or tens of thousands of times, it is still clear. Why is this? Let's first talk about why ordinary pictures are distorted. The ordinary pictures we are talking about now refer to the pictures seen on electronic devices such as computers and mobile phones. These pictures are essentially composed of pixels. When viewing the information of a picture on a computer, there is one very important piece of information, that is, the pixels of the picture, which indicates how many pixels the picture is composed of.

Assuming that the pixel size of an image is 1800X1000, it means that each row of the image is composed of 1800 pixels, and there are a total of 1000 rows.

At normal size, we cannot see these pixels, but if we continue to zoom in on the image, these pixels will appear, and the image will become blurry and distorted. This leads to a problem, that is, the application scope of the image is limited. For example, if we draw a corporate LOGO, when the company wants to apply this LOGO to a large-scale promotional poster, the image will become blurry and distorted due to magnification, so these special images must be drawn as "vector graphics" through special software. Vector graphics are not real pictures. They describe a specific graphic through straight lines and curves. These straight lines and curves are all calculated through mathematical formulas, so they can be converted into pictures of any size without distortion.

Although vector graphics can solve the problem of distortion, in essence they are not real images, but some mathematical formulas. However, microscopes are different. They actually magnify the impact of objects without causing blur and distortion. Why is this?

In fact, the reason is very simple. The image seen under the microscope is not composed of pixels. It reflects the real information of the object. The real information of the object exists objectively, so there is no concept of "distortion". Does this sound a bit difficult to understand? Then let's understand how the microscope forms an image. The earliest microscope was the optical microscope, and its magnification principle is very simple, which is to rely on a convex lens.

The image of an object can be magnified through the optical effect of a convex lens. However, no matter how convex a convex lens is, it is impossible to magnify biological cells to a visible level. But it doesn’t matter. If one lens doesn’t work, use two.

An optical microscope is mainly composed of two lenses, one is the objective lens and the other is the eyepiece. Both lenses have magnifications, so the charm of multiplication is reflected here. For example, the magnification of the eyepiece of a microscope is 10 times, and the magnification of the objective lens is 20 times, then 10 times 20, the magnification of this microscope is 200 times. Therefore, to increase the magnification of a microscope, you only need to increase its eyepiece magnification and objective lens magnification respectively. However, although the image magnified by an optical microscope will not be blurred or distorted, it cannot be magnified infinitely.

Optical microscopes use visible light, and the wavelength of visible light is limited. Due to this limitation, optical microscopes can magnify the image of an object by a maximum of 2000 times. Therefore, there is no problem using an optical microscope to observe biological cells, but if you want to peek into a more microscopic world, it is powerless.

In order to be able to see substances smaller than cells, humans invented the electron microscope. The electron microscope is much larger than the optical microscope. It usually consists of three parts: the lens tube, the vacuum device and the power cabinet. The electron microscope uses a magnetic lens, which is not a real lens. It uses an electric field or a magnetic field to bend the electron trajectory toward the axis to form a focus. In other words, the magnification principle of the electron microscope does not rely on visible light, but replaces visible light with an electron beam and replaces the optical lens with a magnetic field.

Because it is free from the constraints of visible light, the magnification of an electron microscope is more than 1,000 times higher than that of an optical microscope, which means that its magnification can reach millions of times. Under an electron microscope, the DNA in the cell nucleus will be visible.

However, DNA is only a macromolecule, not the most microscopic form of matter. We want to see individual atoms with our own eyes, so a more powerful microscope has emerged, the "scanning tunneling microscope". The scanning tunneling microscope is the most powerful microscope in the world today, and it uses the tunneling effect in quantum theory. The magnification of the scanning tunneling microscope exceeds 300 million times, so through this huge instrument, scientists can even observe and locate individual atoms.

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