The whole history of the microscope

The microscope is one of the greatest inventions of this period. Before it was invented, human's concept of the world around him was limited to what the naked eye could see, or through holding a lens. Microscope shows a brand-new world in human vision. For the first time, people saw hundreds of "new" tiny animals and plants, and all the internal structures from human body to plant fibers. Microscopes also help scientists discover new species and help doctors treat diseases. The earliest microscope was made in Holland at the end of16th century. The inventor may be a Dutch optician named zacarias Zhan Sen, or another Dutch scientist Hans Lipper. They made a simple microscope with two lenses, but they didn't make any important observations with these instruments. Later, two people began to use microscopes in science. The first is the Italian scientist Galileo. He described the compound eyes of insects for the first time after observing them through a microscope. The second is Antoine van Leeuwenhoek, a Dutch linen merchant (1632-1723), who learned to grind lenses by himself. For the first time, he described many tiny plants and animals invisible to the naked eye. 193 1 year, Ernst ruska invented an electron microscope, which completely changed biology. This enables scientists to observe objects as small as a millionth of a millimeter. 1986 won the Nobel Prize.

Edit this microscope-basic introduction

Microscope can be divided into optical microscope and electron microscope according to microscopic principle; Mobility classification can be divided into desktop microscope and portable microscope; Optical microscope usually consists of optical part, illumination part and mechanical part. There is no doubt that the optical part is the most critical, consisting of eyepiece and objective lens. As early as 1590, glasses manufacturers in the Netherlands and Italy have made magnifying instruments similar to microscopes. At present, 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 microscope, polarizing microscope, differential interference difference microscope, inverted microscope and so on. The electron microscope has similar basic structural characteristics to the optical microscope, but it has much higher magnification and resolution than the optical microscope. It uses electron flow as a new light source to image objects. Since ruska invented the first transmission electron microscope in 1938, many other types of electron microscopes have been developed besides the continuous improvement of transmission electron microscope itself. 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 of samples or the relationship between structure and function in many aspects. Microscopes are used to observe images of tiny objects. It is often used in biology, medicine and observation of tiny particles. Desktop microscope mainly refers to the traditional microscope, which is generally large and inconvenient to move, and is mostly used in the laboratory, which is not convenient for going out or on-site testing; Portable microscope, mainly an extension of digital microscope and video microscope series developed in recent years, generally pursues portability, compactness, exquisiteness and portability; Moreover, 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 measurement. As far as I know, there are brands such as Anyty in China. Portable video microscope MSA200

Edit the history of this instrument.

As early as the first century BC, people have found that when observing tiny objects through spherical transparent objects, the images can be enlarged. Later, I gradually realized that the surface energy of spherical glass magnifies the image of an object. In 1590, Dutch and Italian glasses manufacturers have built magnifying instruments similar to microscopes. 16 1 1 year Kepler: The manufacturing method of compound microscope is put forward. Hooke (1665): The origin of the word "cell" was obtained by Hooke's observation of tiny stomata in plant cork tissue with a compound microscope. 1674 Levin Hook: After the publication of the protozoology report, he became the first person to discover the existence of "bacteria" nine years later. Brown (1833): Observe violets under the microscope, and then give his detailed discussion on the nucleus. 1838 Schleiden and Shi Wan (Schleiden and Wang Shi): Both of them advocate the principle of cytology, and their main idea is that nucleated cells are the basic elements of all animal and plant tissues and functions. 1857 Kolliker: Mitochondria were found in muscle cells. 1876 Abbe (ABI): Analyze the diffraction phenomenon when the image is imaged under the microscope, and try to design the most ideal microscope. 1879 Flrmming (Fleming): It is found that when an animal cell is undergoing mitosis, its chromosome activity is clearly visible. 188 1 year Retziue (Ruizu): The animal organization report has come out, and no one can surpass this publication at present. However, 20 years later, a group of histologists led by Cahal developed the microscopic staining observation method, which laid the foundation for the future microscopic anatomy. 1882 Koch (Kirk): He dyed microbial tissues with benzene dye and found cholera and mycobacterium tuberculosis. In the next 20 years, other bacteriologists, such as Kleber and Pasteur (Klebel and Pasteur), confirmed the causes of many diseases by examining the staining drugs under the microscope. 1886 Zeiss: Breaking the limitation of general visible light theory, his invention-Abbey Type and a series of lenses opened up a new world for microscopists to interpret images. 1898 Golgi: the first microscopist to find Golgi in bacteria. He used silver nitrate to dye cells, which made a big step in the study of human cells. Lacassagne (1924): He and his experimental partner * * * jointly developed a radiographic method. The invention uses radioactive polonium to detect biological specimens. 1930 Lebedev: Design and match the first interference microscope. In addition, zernike invented the phase difference microscope in 1932, and the phase difference observer developed by them expanded the traditional optical microscope, enabling biologists to observe various details on stained living cells. 194 1 year Kuhns (Quincy's): fluorescent dye was added to antibody to detect cell antigen. Normaski (1952): invented the interference phase difference optical system. This invention is not only patented, but also named after the inventor himself. 198 1 year Allen and Inoue (Allen and Ainiu): The image enhancement and contrast in the principle of optical microscope tend to be perfect. Confocal scanning microscope (* * *) is widely used in the market.

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Microscope can be divided into optical microscope and electron microscope.

Edit this paragraph of the optical microscope

It was originally created by Zhan Sen and his son in the Netherlands in 1590. Nowadays, the optical microscope can enlarge the object by 1500 times, and the lowest resolution can reach the biological microscope.

0.2 micron. There are many kinds of optical microscopes, except general ones, mainly dark-field microscopes, which have a dark-field condenser, so that the illumination beam does not enter from the central part, but shines on the specimen from the periphery. The fluorescence microscope uses ultraviolet light as the light source to make the irradiated object emit fluorescence. The structure is: eyepiece, lens barrel, converter, objective lens, objective table, light hole, shutter, plate clamp, reflector, lens seat, coarse focusing screw, fine focusing screw, lens arm and lens column.

ultramicroscope

Because the dark field microscope does not inject transparent light into the direct observation system, the field of view is dark when there is no object, so it is impossible to observe any object. When there is an object, the diffracted light and scattered light of the object are bright and visible in the dark background. When observing an object in a dark field, most of the illumination light is reflected back. Because of the different position, structure and thickness of the object (specimen), the scattering and refraction of light have great changes.

phase contrast microscope

Structure of phase contrast microscope: Phase contrast microscope is a microscope using phase contrast method. Therefore, the microscope should add the following accessories: (1) objective lens with phase plate (phase annular plate) and phase difference objective lens. (2) A condenser with a phase ring (annular slit plate) and a phase difference condenser. (3) Monochrome filter-(green). Performance description of various components (1) The phase plate shifts the phase of direct light by 90, absorbing and weakening the intensity of light. The phase plate must be installed in the appropriate position of the back focal plane of the objective lens, and the brightness must be guaranteed. In order to make the influence of diffracted light less, the phase plate is made into a ring shape. (2) The phase ring (annular aperture) can be replaced by a turntable according to the magnification of each objective lens. (3) The monochromatic filter is a green filter with a central wavelength of 546nm (nanometer). Usually monochromatic filters are used for observation. The phase plate moves 90 degrees at a specific wavelength to see the phase of the direct light. When a specific wavelength is needed, the appropriate filter must be selected, and the contrast will be improved after inserting the filter. In addition, the center of the phase ring seam must be adjusted to the correct orientation to operate, and the centering telescope is the component that plays this role.

Video microscope

The traditional microscope combines a camera system, a display or a computer to achieve the purpose of magnifying and observing the measured object. Video microscope can also be called digital microscope.

The earliest prototype should be a camera microscope. Through the principle of pinhole imaging, the images obtained under the microscope are projected onto the photosensitive photos, so as to get the picture. Or directly dock the camera with the microscope to take pictures. With the rise of CCD camera, microscope can transmit real-time images to TV or monitor for direct observation and shooting with camera. In the mid-1980s, with the development of digital industry and computer industry, the function of microscope has been improved through them, making it simpler and easier to operate. By the end of 1990s, with the development of the semiconductor industry, the wafer demanded that the microscope could bring more coordination functions. The combination of hardware and software makes the microscope more intelligent and humanized, and makes the microscope have a greater development in industry.

fluorescent microscope

In the fluorescence microscope, excitation light with a specific wavelength must be selected from the illumination light of the sample to generate fluorescence, and then the fluorescence must be separated from the mixed light of excitation light and fluorescence for observation. Therefore, the filter system plays an extremely important role in the selection of specific wavelengths. Principle of fluorescence microscope: (1) light source: the light source radiates light of various wavelengths (from ultraviolet to infrared). (b) Excitation filter light source: transmits light with a specific wavelength that can make the sample emit fluorescence, and at the same time blocks light that is useless for excitation fluorescence. (c) Fluorescent specimens: generally stained with fluorescent pigments. (d) Blocking filter: blocking the excitation light that is not absorbed by the specimen, so that the fluorescence is selectively transmitted, and some wavelengths in the fluorescence are also selectively transmitted. A microscope that uses ultraviolet light as the light source to make the irradiated object emit fluorescence. The electron microscope was first assembled by Noel and Ha Roska in Berlin in 193 1. This microscope uses high-speed electron beams instead of light beams. Because the wavelength of electron flow is much shorter than that of light wave, the magnification of electron microscope can reach 800 thousand times, and the lowest resolution limit is 0.2 nm. 1963 uses a scanning electron microscope, which enables people to see the tiny structures on the surface of objects. Microscopes are used to enlarge images of tiny objects. Generally used in biology, medicine and observation of microscopic particles. (1) Use the movement of the micro stage to measure the length with the cross mark of the whole eyepiece. (2) Use the rotary table and the cursor differential angle dial at the lower end of the eyepiece to match the address mark of the eyepiece to measure the angle, so that one end of the measured angle is aligned with the reticle and coincides with it, and then the other end coincides with it. (3) Check the pitch, middle diameter, outer diameter, tooth angle and tooth profile of the thread with standard. (4) Check the grain condition on the metallographic surface. (5) Check the condition of the machined surface of the workpiece. (6) Check whether the size or outline of the tiny workpiece is consistent with the standard parts.

Micrometer polarizer

Polarizing microscope is a kind of microscope used to study so-called transparent and opaque anisotropic materials. Under the polarizing microscope, all substances with birefringence can be clearly distinguished. Of course, these substances can also be observed by dyeing, but some of them are impossible, and a polarizing microscope must be used. micropolariscope

(1) Characteristics of Polarizing Microscope A method of changing ordinary light into polarized light for microscopic examination, so as to identify whether a substance is single refraction (isotropic) or birefringence (anisotropic). Birefringence is the basic characteristic of crystals. Therefore, polarizing microscope is widely used in the fields of minerals, chemistry, biology and botany. (2) The basic principle of polarizing microscope The principle of polarizing microscope is complicated, so I won't introduce it too much here. Polarizing microscope must have the following accessories: polarizer, analyzer, compensator or phase plate, special stress-free objective lens and rotary stage.

ultrasonic microscope

The characteristic of ultrasonic scanning microscope is that it can accurately reflect the interaction between sound waves and the elastic medium of tiny samples, and analyze the signals fed back from inside the samples! Each pixel in the image (C-scan) corresponds to a signal fed back by a two-dimensional coordinate point at a certain depth in the sample. Z. A sensor with good focusing function can simultaneously transmit and receive acoustic signals. Therefore, a complete image is formed by scanning samples point by point and line by line. The reflected ultrasonic wave plus positive or negative amplitude makes the depth of the sample can be reflected by the time of signal transmission. The digital waveform on the user's screen shows the received feedback information (A scan). Set the corresponding gate circuit, with this quantitative time difference measurement (feedback time display), you can choose the depth of the sample you want to observe.

dissecting microscope

Dissecting microscope, also known as solid microscope or stereoscopic microscope, is a microscope designed for different work requirements. When observed by dissecting microscope, the light entering the eyes comes from an independent light path, and these two light paths have only a small angle, so the sample can present a three-dimensional appearance when observed. There are two kinds of optical path designs in dissecting microscope: Greenough type and telescope type. Dissecting microscope is often used for surface observation of some solid samples, or for dissection, clock making and small circuit board inspection.

* * * focusing microscope

The probe light emitted from the point light source is focused on the observed object through the lens. If the object is just in focus, the reflected light will converge back to the light source through the original lens, which is called * * * focusing, or * * * focusing for short. * * * Focusing Microscope [Confocal Laser Scanning Microscope (CLSM or LSCM)] A half mirror is added to the optical path of the reflected light, which refracts the reflected light that has passed through the lens to other directions. It has a pinhole at the focus, and the pinhole is located at the focus. Behind the baffle is a photomultiplier tube (PMT). As you can imagine, the reflected light before and after the focusing of the probe light passes through this * * * focusing system, and will not be focused on the small hole, but will be blocked by the baffle. Therefore, the photometer measures the intensity of reflected light at the focal point. Its significance lies in that the translucent object can be scanned in three dimensions by moving the lens system.

metallurgical microscope

MC006-5XB-PC metallographic microscope is mainly used to identify and analyze the internal structure and microstructure of metals. It is not only an important instrument for metallographic research, but also a key equipment for industrial departments to identify product quality. The instrument is equipped with a camera device, which can shoot metallographs, measure and analyze metallographs, and edit, output, store and manage images. There are many manufacturers with a long history in China. Such as Shanghai Zhongyan Instrument Factory! Specification: 1, eyepiece barrel: inclination angle 30, eye pupil adjustment range 55mm-75mm ~ 2, eyepiece: eyepiece:10 (150 * 200mm) 3. Five-hole objective lens converter (generally four holes): PL20X, PL.