Introduction to resolution of microscope structure microscope
Microscope is an optical instrument composed of a lens or a combination of several lenses, which is a sign that human beings have entered the atomic age. It is mainly used to enlarge tiny objects into instruments that can be seen by human naked eyes.
Microscope structure
An optical microscope consists of an eyepiece, an objective lens, a coarse focusing screw, a fine focusing screw, a tablet holder, a light hole, a shutter, a converter, a reflector, an object stage, a lens arm, a lens barrel, a lens seat, a condenser and an aperture.
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 from a point on the optical axis to the objective lens)
To improve the resolution, we can: 1. Reduce λ, for example, use ultraviolet light as a light source; 2. increase n, for example, put it in fragrant asphalt; 3. Increase α, that is, reduce the distance between the objective lens and the specimen as much as possible.
Microscopic classification
Microscopes can be classified into optical microscopes, electronic microscopes and digital microscopes according to microscopic principles.
optical microscope
Usually consists of optical part, lighting part and mechanical part. Undoubtedly, the optical part is the most critical, which consists of eyepiece and objective lens. As early as 1590, Dutch and Italian glasses manufacturers had built magnifying instruments similar to microscopes. There are many kinds of optical microscopes, mainly including bright field microscope (ordinary optical microscope), dark field microscope, fluorescence microscope, phase contrast microscope, laser scanning confocal microscope, polarizing microscope, differential interference difference microscope and inverted microscope.
electron microscope
The electron microscope has similar basic structural characteristics to the optical microscope, but it has much higher magnification and resolution ability than the optical microscope. It uses electron flow as a new light source to image the object. Since Ruska invented the first transmission electron microscope in 1938, in addition to the continuous improvement of the performance of transmission electron microscope itself, many other types of electron microscopes have been developed. Such as scanning electron microscope, analytical electron microscope, ultra-high pressure electron microscope, etc. Combined with various electron microscope sample preparation techniques, we can study the structure or the relationship between structure and function of samples in many aspects. Microscopes are used to observe images of tiny objects. It is often used for the observation of biology, medicine and tiny particles. An electron microscope can magnify an object to 2 million times.
Desktop microscope, mainly refers to the traditional microscope, is pure optical amplification, with high magnification and good imaging quality, but it is generally large and inconvenient to move, and is mostly used in the laboratory, which is inconvenient for going out or on-site detection.
Portable microscope
Portable microscope is mainly an extension of digital microscope and video microscope series developed in recent years. Different from traditional optical amplification, handheld microscopes are all digital amplification, which generally pursues portability, compactness and exquisiteness, and is easy to carry; And some hand-held microscopes have their own screens, which can be imaged independently from the computer host, which is convenient to operate, and can also integrate some digital functions, such as supporting photography, video recording, or image comparison and measurement.
Digital liquid crystal microscope was first developed and produced by Boyu Company. This microscope retains the clarity of optical microscope, and integrates the advantages of powerful expansion of digital microscope, intuitive display of video microscope and simplicity and convenience of portable microscope.
STM
Scanning tunneling microscope, also known as "scanning tunneling microscope" and "tunneling scanning microscope", is an instrument that uses the tunneling effect in quantum theory to detect the surface structure of substances. It was invented by G. Gerd G.Binning and H. heinrich H.Rohrer in 1981 at IBM's Zurich laboratory in Zurich, Switzerland, so the two inventors shared the 1986 Nobel Prize in Physics with Ernst ruska.
As a scanning probe microscopy tool, scanning tunneling microscope allows scientists to observe and locate a single atom, and it has higher resolution than its similar atomic force microscope. In addition, scanning tunneling microscope (STM) can accurately manipulate atoms with probe tips at low temperature (4K), so it is both an important measuring tool and a processing tool in nanotechnology.
