Structure and resolution of the microscope
A microscope is an optical instrument composed of a lens or a combination of several lenses, and it is a sign that human beings have entered the atomic age. It is mainly used to magnify tiny objects into instruments that can be seen by human eyes.
microscope structure
Optical microscope consists of eyepiece, objective lens, coarse quasi-focus helix, fine quasi-focus helix, clip, aperture, shutter, converter, mirror, stage, mirror arm, lens barrel, mirror base, condenser , composed of apertures.
Microscope resolution
D=0.61λ/N*sin(α/2)
D: Resolution
λ: wavelength of light source
α: Angle of the objective lens (the opening angle of the specimen at a point on the optical axis to the objective lens opening)
If you want to improve the resolution, you can: 1. Reduce λ, such as using ultraviolet light as a light source; 2. Increase N, such as placing it in cedar oil; 3. Increase α, that is, reduce the distance between the objective lens and the specimen as much as possible .
Microscope Classification
Microscopes are classified according to microscopic principles and can be divided into optical microscopes, electron microscopes and digital microscopes.
Optical microscope
It usually consists of optical part, lighting part and mechanical part. There is no doubt that the optical part is the most critical, it consists of eyepiece and objective lens. As early as 1590, Dutch and Italian eyeglass makers had built magnifying instruments similar to microscopes. There are many types of optical microscopes, mainly bright field microscopes (ordinary optical microscopes), dark field microscopes, fluorescence microscopes, phase contrast microscopes, laser scanning confocal microscopes, polarizing microscopes, differential interference contrast microscopes, and inverted microscopes.
electron microscope
Electron microscopes have similar basic structural features to optical microscopes, but they have much higher magnification and resolution capabilities than optical microscopes. They use electron flow as a new light source to image objects. Since Ruska invented the first transmission electron microscope in 1938, in addition to the continuous improvement of the performance of the transmission electron microscope itself, many other types of electron microscopes have also been developed. Such as scanning electron microscope, analytical electron microscope, ultra high voltage electron microscope and so on. Combined with various electron microscope sample preparation techniques, it is possible to conduct in-depth research on the structure of the sample or the relationship between structure and function. Microscopes are used to observe images of tiny objects. It is often used in the observation of biology, medicine and tiny particles. Electron microscopes can magnify objects up to 2 million times.
Desktop microscopes mainly refer to traditional microscopes, which are purely optical magnification, with high magnification and good image quality, but they are generally large in size and inconvenient to move.
portable microscope
Portable microscopes are mainly extensions of the series of digital microscopes and video microscopes developed in recent years. Different from traditional optical magnification, hand-held microscopes are all digital magnifications. They are generally portable, small and exquisite, and easy to carry; and some hand-held microscopes have their own screens, which can be imaged independently from the computer host, easy to operate, and can also be integrated Some digital functions, such as support for taking pictures, video recording, or image comparison, measurement and other functions.
The digital liquid crystal microscope was first developed and produced by Boyu Company. This microscope retains the clarity of the optical microscope, and combines the advantages of the powerful expansion of the digital microscope, the intuitive display of the video microscope, and the simplicity and convenience of the portable microscope.
scanning tunneling microscope
Scanning tunneling microscope, also known as "scanning tunneling microscope" and "tunnel scanning microscope", is an instrument that uses the tunneling effect in quantum theory to detect the surface structure of substances. It was invented by Gerd Binning (G.Binning) and Heinrich Rohrer (H.Rohrer) in IBM's Zurich Laboratory in Zurich, Switzerland in 1981. The two inventors therefore cooperated with Ernst Ruska shared the 1986 Nobel Prize in Physics.
As a scanning probe microscopy tool, the scanning tunneling microscope allows scientists to observe and locate individual atoms at a much higher resolution than its atomic force microscope counterpart. In addition, the scanning tunneling microscope can precisely manipulate atoms with the tip of the probe at low temperature (4K), so it is both an important measurement tool and a processing tool in nanotechnology.
