Microscope

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Scientific research instruments and equipment

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Microscope is a kind of lens or combination of several lenses optical instrument It is a sign that mankind has entered the atomic age.^[1] Microscope is an instrument mainly used to magnify small objects to be seen by human eyes. Microscope minute optical microscope and electron microscope : The optical microscope was first created by Jensen of the Netherlands in 1590. The current optical microscope can magnify the object 1600 times, and the minimum resolution limit is 1/2 of the wavelength. The length of the domestic microscope mechanical cylinder is generally 160 mm. For the development of microscope, microbiology People who have made great contributions Leeuwenhoek ， Netherlands Nationals.

Chinese name: Microscope
Foreign name: microscope

Properties: optical instrument
Classification: Optical microscope, electron microscope, polarizing microscope, portable microscope, scanning tunneling microscope

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Invention process

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Microscope is one of the greatest inventions of mankind. Before it was invented, human beings Surrounding world The concept of "is limited to what the naked eye sees with the naked eye, or what the naked eye sees with a hand-held lens.".

Microscope has opened a new world to human vision. For the first time, people have seen hundreds of "new" micro animals and plants, and Plant fibre The internal structure of various things. Microscopes also help scientists Discover new species , help doctors treat diseases.

The earliest microscope was in the late 16th century Netherlands Made. The inventor is Yas Jensen , a Dutch optician, or another Dutch scientist Hans Lipsey They made a simple microscope with two lenses, but did not make any important observation with these instruments.

Later, two people began to use microscopes in science. The first one is Italy scientist Galileo 。 He observed a kind of insect After that, its compound eye was described for the first time. The second was Leeuwenhoek, a Dutch linen merchant (1632-1723), who learned to grind lenses himself. For the first time, he described many tiny plants and animals invisible to the naked eye.

Encyclopedia x ignorance: graphic Leeuwenhoek

In 1931, Ernst Ruska The development of electron microscope has revolutionized biology. This allows scientists to observe objects as small as one millionth of a millimeter. In 1986, he was awarded Nobel Prize 。

Microscope structure

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Structure diagram of simple microscope (3 sheets)

The optical microscope consists of an eyepiece, an objective lens, a coarse focusing spiral, a fine focusing spiral, a tablet holder, a through hole, a light shield, converter , reflector; Stage ， Mirror arm , mirror tube, mirror base, Condenser ， Diaphragm form.

Microscope resolution

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D=0.61λ/N*sin（α/2）

D: Resolution

λ: Light source wavelength

α: The mouth angle of the objective lens (the specimen is in optic axis One point of

To improve the resolution, you can: 1. reduce λ, for example, use ultraviolet rays As a light source; 2. Increase N, for example, place Cedar oil Medium; 3. Increase α, that is, reduce the distance between the objective lens and the specimen as much as possible

Microscopic classification

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Microscopes can be classified into Polarizing microscope 、 optical microscope 、 electron microscope 、 Digital microscope Etc.

Polarizing microscope

Polarizing microscope (Polarizing microscope) is used to study the so-called transparency and Opaque anisotropy A microscope for materials, in geology, etc Science and Engineering It has important applications. Where there is Birefringence The substance in Polarization It can be clearly distinguished under the microscope, but these substances can also be used Dyeing method To observe, but some are not available and must use a polarizing microscope. The reflection polarizing microscope uses Polarization of light Property pair has Birefringence It is a necessary instrument for research and identification of substances, which can be used by users for single polarized light observation, crossed polars Observation, cone light observation.

optical microscope

It usually consists of optical part, lighting part and mechanical part. Undoubtedly, the optical part is the most critical part, which is composed of eyepiece and objective lense form. As early as 1590, Netherlands and Italy Eighty five percent of eyewear manufacturers have built magnifying instruments similar to microscopes. optical microscope There are many kinds of Bright field microscope （ General optical microscope ）、 Dark field microscope 、 fluorescence microscope 、 Phase contrast microscope 、 Laser scanning confocal microscope 、 Polarizing microscope 、 Differential interference microscope 、 inverted microscope 。

electron microscope

The electron microscope is similar to the optical microscope Basic structure But it has much higher magnification and Discriminative ability , it will Electron flow As a new light source, the object is imaged. Ruska invented the first set since 1938 transmission electron microscope So far, except Transmission electron microscope In addition to the continuous improvement of its own performance, many other types of electron microscopes have also been developed. as scanning electron microscope , analytical electron microscope Ultrahigh pressure Electron microscope, etc. Combined with various electron microscopes Sample preparation Technology, which can be applied to the sample in many aspects Functional relationship In-depth research. Microscopes are used to observe images of small objects. It is often used for observation of biology, medicine and small particles. An electron microscope can magnify an object to 2 million times.

The desk microscope, mainly referring to the traditional microscope, is purely optical amplification Magnification High, good imaging quality, but generally large, not easy to move, mostly used in the laboratory, inconvenient to go out or on-site testing.

Portable microscope

A high-end microscope and its accessories

Portable microscope, mainly developed in recent years Digital microscope And video microscope series. Different from traditional optical amplification, Hand-held microscope Both Digital amplification It generally pursues portability, small and exquisite, easy to carry; Moreover, some handheld microscopes have their own screens, which can be separated from the computer host for independent imaging, easy to operate, and can also integrate some digital functions, such as supporting photography, video recording, or image comparison, measurement and other functions.

Digital liquid crystal microscope It was first developed and produced by Boyu Company. The microscope retains the clarity of the optical microscope and combines the advantages of the powerful expansion of the digital microscope, the visual 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"“ Tunnel scanning microscope ”, is a kind of utilization Quantum Theory In Tunnel effect Detection material surface structure Instrument. It was founded in 1981 by Gerd Binnig (G. Binning) and Heinrich Rohrer (H. Rohrer) IBM Located in Switzerland Zurich Was invented by the Zurich Laboratory of Ernst Ruska Shared 1986 The nobel prize in physics 。

As a kind of scanning probe microscopy Tools, scanning tunneling microscope can allow scientists to observe and locate a single atom, which has more advantages than its peers atomic force microscope Higher resolution. In addition, the scanning tunneling microscope（ 4K ）The probe tip can be used to manipulate atoms precisely, so it can Nanotechnology Both important Measuring tools It is also a processing tool.

STM For the first time, human beings can observe the arrangement of single atoms on the surface of matter and the physicochemical properties related to the electronic behavior of the surface in real time Surface science 、 material science , life science and other fields have great significance and broad application prospects, and are recognized by the international scientific community as one of the world's top ten scientific and technological achievements in the 1980s.

Development history

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As early as the first century BC, it was found that when observing small objects through spherical transparent objects, they can be magnified and imaged. Later, I gradually got to know the rule that spherical glass surface can make objects magnify and image.

1590 , Z Jansen of the Netherlands and the eyewear manufacturer of the Italians have built magnifying instruments similar to microscopes.

1611 Kepler (Kepler): proposed the manufacturing method of compound microscope.

1665 ，R·Hooke( Robert Hooke ）The origin of the term "cell" was observed by Huckley with a compound microscope cork Of Cork tissue It is obtained from the tiny pores on the.

1674 , A · V · Leeuwenhoek: Protozoology Nine years later, he became the first person to discover the existence of "bacteria".

1833 , Brown: Observe under the microscope violet , and later published his comments on nucleus Detailed discussion of.

1838 ，Schlieden and Schwann( Schleiden and Shiwang ）: All advocated cytology Principle, whose main purpose is " Nucleated cell It is the basic element of the organization and function of all animals and plants.

1857 , Kolliker: Muscle cell Middle mitochondrion 。

1876 Abbe: Anatomy image generated when imaging in microscope diffraction To try to design the most ideal microscope.

Biological microscope

1879 , Fleming: found that when Animal cell During mitosis, the activity of its chromosomes is clearly visible.

1881 , Retziue: Animal tissue When the report was published, no one could surpass it. However, 20 years later, a group of histologists led by Cajal developed microscopic staining Observation method , this is a future Microanatomy The foundation has been laid.

1882 , Koch: Using Benzane dyestuff Staining microbial tissue, he found cholera and Mycobacterium tuberculosis 。 In the next 20 years, other Bacteriologist Klebs and Pasteur, for example, confirmed the cause of many diseases by examining staining drugs under a microscope.

1886 , Zeiss: break the ordinary visible light The limit of theory, his invention - Abby type and a series of other lenses have opened up a new world for microscopic scholars to interpret images.

1898 , Golgi: the first bacteria found Golgi apparatus A microscopic scientist. He uses cells silver nitrate Staining has made a big step in human cell research.

1924 , Lacassagne: and his experimental partners common development Out Radiation Photography, this invention is to use Radiopolonium Elements to explore Biological specimen 。

1930 , Lebedeff: design and match the first Interference microscope 。 In addition, it was invented by Zernicke in 1932 phase difference Microscope, the phase difference developed by two people from the traditional optical microscope observer Biologists can observe the staining Living cell Details on the.

1941 Coons: Antibodies are added with fluorescent dyes to detect cell antigens.

1952 , Nomarski: invention of interference phase difference optical system 。 This invention not only enjoys patent right And named after the inventor himself.

1981 , Allen and Inoue: Image enhancement By contrast, development tends to be perfect.

1988 Confocal scanning microscope is widely used in the market.

Digital microscope

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Microscope

The digital microscope is an excellent optical microscope Technical and advanced Photoelectric conversion technology 、 LCD screen An item that has been successfully developed with perfect combination of technologies high-tech product 。 Thus, we can study the micro field from the traditional ordinary binocular observation to the reproduction on the display, thus improving the work efficiency 。

optical microscope

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It was first created by Jensen and his son in the Netherlands in 1590. The optical microscope can magnify the object 1600 times, and the minimum resolution limit is 0.1 μ m. There are many kinds of optical microscopes, including Dark field microscope One with Dark field of vision Condenser, so that the light beam does not enter from the central part, but from the surrounding to the microscope of the specimen fluorescence microscope A microscope that uses ultraviolet light as the light source to make the irradiated object emit fluorescence. The structure is: eyepiece, lens barrel, converter, objective lens, stage, light hole, sunshade, compression clip, reflector, mirror base, coarse collimation spiral, fine collimation spiral, mirror arm, mirror column.

Dark field microscope

Since the dark field microscope does not inject transparent light into the direct observation system, when there is no object, the field of vision is dark, and it is impossible to observe any object. When there is an object, the light diffracted by the object and Scattered light It is bright and visible in the dark background. In dark vision Observe objects Most of the illumination light is turned back. Due to the different position, structure and thickness of the object (specimen), the scattering and refraction of light have great changes.

Phase difference microscope

phase difference Structure of microscope: phase difference microscope, which applies phase difference method. Therefore, the following accessories shall be added to the microscope:

(1) With Phase plate (Phase ring plate) objective lens, phase difference objective lens.

(2) Condenser with phase ring (annular slit plate), phase difference condenser.

(3) Monochrome Filter -(Green).

Performance description of various elements

(1) The phase plate moves the phase of direct light by 90 °, and absorbs and weakens the intensity of light behind the objective lens focal plane The phase plate shall be installed at the appropriate position of the. The phase plate must ensure the brightness. In order to reduce the influence of diffracted light, the phase plate shall be made into a ring shape.

(2) The phase ring (annular aperture) is based on the Multiplication , but different sizes can be replaced with turntable.

Overall shape of phase difference microscope

(3) Monochromatic filter system Central wavelength 546nm( Nanometre ）Green filter. It is usually observed with a monochromatic filter. The phase plate uses a specific wavelength, and moves 90 ° to view directly Phase of light 。 When a specific wavelength is required, an appropriate filter must be selected. After the filter is inserted contrast ratio Just improve. In addition, the center of the phase annular seam must be adjusted to the correct orientation before operation, and the centering telescope is the part that plays this role.

Video microscope

The traditional microscope is combined with the camera system, display or computer to achieve the purpose of magnifying the measured object. The earliest prototype should be a camera microscope. The image obtained under the microscope is projected onto a photosensitive photograph through the principle of pinhole imaging to obtain a picture. Or directly connect the camera with the microscope to take pictures. along with CCD camera With the rise of, microscopes can transfer real-time images to televisions or monitor It can be directly observed and photographed by camera. In the mid-1980s, with the digital industry and Computer industry The function of microscope has also been improved through them, making it easier to operate. By the end of the 1990s, Semiconductor industry The development of, wafer It is required that the microscope can bring more matching functions. The combination of hardware and software, intelligence and humanization have made the microscope have greater development in industry.

Video microscope

With the maturity of the application of CMOS lens technology in microscope field and the development of digital output technology, the video microscopes on the market are not only the video microscopes that display microscopic pictures through PC, but also the video microscopes with independent screens, such as the MSV35 of 3R; Yes, via wireless transmission mode The mobile wireless video microscope is separated from the display of PC, such as the WM401TV and WM601TV of 3R, and the size of the CMOS lens microscope is more exquisite than the traditional microscope, which can be used for on-site microscopic observation.

fluorescence microscope

On the fluorescence microscope, the excitation light of a specific wavelength must be selected from the illumination light of the specimen to generate fluorescence, and then the fluorescence must be separated from the excitation light and fluorescence mixed light for observation. Therefore, the filter system plays an extremely important role in selecting a specific wavelength.

Principle of fluorescence microscope:

(A) Light source: The light source radiates light of various wavelengths (from ultraviolet to infrared).

(B) Excitation filter light source: transmits the light of specific wavelength that can make the specimen produce fluorescence, and blocks the light that is useless for excitation fluorescence.

(D) Blocking filter: it selectively transmits fluorescence by blocking the stimulated light that is not absorbed by the specimen, and some wavelengths of 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 in Germany in 1931 Berlin It was first assembled by Knorr Bremse and Haroska. This microscope uses high-speed electron beams instead of light beams. because Electron flow The wavelength of is much shorter than light wave, so the magnification of electron microscope can reach 800000 times, and the minimum resolution limit is 0.2nm. Used since 1963 scanning electron microscope It can also make people see the micro structure on the surface of objects.

Microscopes are used to magnify images of small objects. It is generally used for biological, medical Microparticle Etc.

(1) Use inching Stage The movement shall be measured with the crosshead marking of the full eyepiece.

(2) Use the rotating stage and the lower end of the eyepiece cursor The differential angle plate is used to measure the angle with the cross mark of the full eyepiece angle measurement Align one end with the cross Line and And then make the other end coincide.

(3) Use the standard to detect the thread Pitch 、 Pitch diameter , outer diameter Tooth angle and Dentition Equal size or shape.

(4) Inspect the grain condition of the metallographic surface.

(5) Inspect the condition of the machined surface of the workpiece.

(6) Check whether the size or contour of the small workpiece is consistent with the standard piece.

Polarizing microscope

Polarized light microscope

Polarizing microscope It is used to study the so-called transparency and Opaque anisotropy A microscope for materials. Where there is Birefringence We can clearly distinguish these substances under a polarizing microscope. Of course, these substances can also be used Dyeing method But some are impossible, and must use a polarizing microscope. (1) Characteristics of polarizing microscope

Change ordinary light to polarized light A method of microscopic examination to identify whether a substance is Monorefraction (in the same direction) or Birefringence (Anisotropy). Birefringence is crystal Basic characteristics of. Therefore, polarizing microscope is widely used in mineral, chemical and other fields, as well as in biology and botany.

(2) Basic principle of polarizing microscope

The principle of the polarizing microscope is relatively complex, and it will not be introduced too much here. The polarizing microscope must have the following accessories: Polarizer ， Polarizer ， Compensator Or phase plate, special stress free objective lens, rotating stage.

Ultrasonic microscope

The characteristic of ultrasonic scanning microscope is that it can accurately reflect the sound wave and the Elastic medium And analyze the signals fed back from the sample! Each pixel in the image (C-Scan) corresponds to a specific depth in the sample 2D space Coordinate points The signal feedback of Z A sensor can transmit and receive acoustic signals at the same time. A complete image is formed by scanning the sample point by point and line by line. The reflected ultrasonic wave is attached with a positive or negative amplitude In this way, the signal transmission time can reflect the depth of the sample. On the user screen Digital waveform Show the received feedback information （A-Scan）。 Set the corresponding Gate circuit With this quantitative time difference measurement (feedback time display), you can select the sample depth you want to observe.

Anatomical microscope

Microscope

Anatomy microscope (stereo microscope, stereomicroscope) (7 sheets)

Anatomical microscope , also known as solid microscope Stereo microscope or Stereoscopic microscope The microscope is designed for different work requirements. When observing with an anatomical microscope, the light entering both eyes comes from an independent path, and these two paths only clip a small angle, so the sample can show a three-dimensional appearance when observing. There are two kinds of light path design of anatomy microscope: The Greenough Concept and The Telescope Concept. Anatomic microscope is often used for surface observation of some solid samples, or for dissection, clock making, small circuit board inspection, etc.

Confocal microscope

From a Point source The emitted detection light is focused on the observed object through the lens. If the object is in the focus, then reflected light Through the original lens, it should converge back to the light source, which is called Confocal , referred to as confocal. Laser scanning confocal microscope [Confocal Laser Scanning Microscope (CLSM or LSCM ）]A half reflection is added to the light path of reflected light Semilens (dichroic mirror), turn the reflected light that has passed through the lens to other directions, and there is a pinhole (Pinhole), the small hole is at the focus, and behind the baffle is a Photomultiplier tube (photomultiplier tube， PMT )。 It can be imagined that the reflected light before and after the detection light focus will not focus on the small hole and will be blocked by the baffle through this confocal system. therefore Photometer It measures the reflection at the focus light intensity 。 Its meaning is: by moving Lens system It can be applied to a translucent object 3D scanning 。

metallurgical microscope

metallurgical microscope It is mainly used to identify and analyze the internal structure and organization of metals. It is a study of metallurgy Metallography The important instrument of industrial sector appraisal product quality Of Key equipment The instrument is equipped with a camera device, which can take the metallographic atlas and Measurement analysis To edit, output, store and manage the image. There are many domestic manufacturers with a long history.

Biological microscope

Biological microscope (4 sheets)

Biological microscope Is used to Observation of living things Slice Biological cell , bacteria and living tissue culture The observation and research of fluid precipitation, other transparent or translucent objects, powders, fine particles and other objects can be observed at the same time. So is the biological microscope food manufacturer Drinking water plant office QS 、 HACCP certification The necessary inspection equipment of.

Use: for biology bacteriology 、 Histology 、 Pharmaceutical chemistry And other research work and clinical experience. With coarse and micro coaxial focusing mechanism, ball Internal positioning converter, brightness adjustable Lighting device With photography and video interface.

Transmission and reflection polarizing microscope

Reflective type Polarization Microscope, with the continuous progress of optical technology, as a polarizing microscope Scope of application It is also becoming more and more extensive. Many industries, such as chemical industry Chemical fibre , semiconductor industry and Drug inspection Polarizing microscope is also widely used. The XPV-213 transmission polarizing microscope is a very suitable product, which can be used by users for single polarized observation, crossed polars Observation, cone light observation and Photomicrography , equipped with gypsum λ mica λ/4 test piece, quartz wedge, moving ruler and other accessories are a group of new products with relatively complete functions and good quality Scalability , can be connected to computer and Digital camera 。 Save, edit, and print pictures.

electron microscope

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Now the maximum magnification of the electron microscope is more than 15 million times,

In 1931, M. Knorr and E. Ruska of Germany used cold cathode discharge Electronic source And three electronic lenses High voltage oscilloscope The invention of transmission electron microscope confirmed the possibility of electron microscope magnification imaging. In 1932, after the improvement of Ruska Resolution It has reached 50nm, about ten times the resolving power of the optical microscope at that time, breaking through the optical microscope Resolution limit So the electron microscope began to attract people's attention.

In the 1940s, Hill used Stigmator Compensate the rotation of the electronic lens Asymmetry The resolution ability of the electron microscope has made a new breakthrough and has gradually reached the modern level. In China, it was successfully developed in 1958 Transmission electron microscope It has a resolution of 3 nm. In 1979, it made a large electron microscope with a resolution of 0.3 nm.

Although the resolving power of the electron microscope is far better than that of the optical microscope, it is difficult to observe living organisms because the electron microscope needs to work under vacuum conditions, and the irradiation of the electron beam will also make Biological sample suffer Irradiation damage 。 Other problems, such as the brightness of the electron gun and the improvement of the quality of the electron lens, also need to be further studied.

Field emission scanning electron microscope

Main purpose: the instrument has ultra-high resolution and can be used for various solid samples surface topography Of Secondary electron Image, reflected electron image observation and image processing 。 It has a high-performance X-ray energy spectrometer, which can simultaneously determine the nature Semiquantitative And quantitative analysis, with comprehensive morphology and chemical composition Analytical capability 。

Instrument category: 03040702/instrument/optical instrument/ Electron optics And ion optical instruments

Index information: secondary electron image resolution: 1.5nm Acceleration voltage: 0~30kV Amplification: 100000~500000 times continuously adjustable Working distance : 5~35mm continuously adjustable tilt: - 5 °~45 ° X-ray spectrometer: resolution: 133eV Analysis range: B-U

Attachment information: gold and carbon plating instrument ISIS image processing system Backscattering probe

Field emission scanning electron microscope, due to its high resolution, is nanometer material Our research provides reliable Experimental means 。 In addition, yes semiconductor material and insulator , can get satisfactory images, right Superconducting film ， magnetic material ， molecular beam epitaxy Growing Film material The morphology of semiconductor materials was observed, and the micro area composition analysis of various materials was carried out, and satisfactory results were obtained

Instrument structure

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Optical microscope structure

General optical microscope The structure of is mainly divided into three parts: mechanical part, lighting part and optical part.

◆ Mechanical part

Microscope structure diagram

(1) Mirror base: It is the base of the microscope to support the whole mirror body.

(2) Mirror column: the upright part above the mirror base, which is used to connect the mirror base and Mirror arm 。

(3) Mirror arm: one end is connected to the mirror column, and the other end is connected to the mirror tube. It is the hand holding part when taking and placing the microscope.

(4) Mirror tube: connected to the upper front of the mirror arm, and the upper end of the mirror tube is equipped with eyepiece , the lower end is equipped with Objective lens converter 。

（5） objective lense converter ( Rotator ）Referred to as "rotator": connected to the lower part of the prism shell, it can rotate freely. There are 3-4 circular holes on the plate, which is the part where the objective lens is installed. Turning the converter, it can change the objective lens of different multiples. When the knock sound is heard, it can be observed. At this time, the objective lens optic axis Just align with the center of the light hole, and the light path is connected. After changing the objective lens, it is not allowed to use thick Regulator Only fine adjuster can be used to make the image clear.

(6) Mirror stand（ Stage ）: Under the mirror tube, there are square and round shapes for placement slide Specimen, there is a light hole in the center, and the microscope we use has a slide specimen on its lens propeller (Slide pusher), there is a spring clip on the left side of the pusher to hold the slide specimen, and there is a pusher adjusting wheel under the mirror platform to move the slide specimen in the left, right, front and back directions.

(7) Regulator: It is a large and small spiral mounted on the mirror column, which makes the mirror table move up and down during adjustment.

① Coarse adjuster (coarse quasi focus spiral): large Spiral scale The coarse adjuster can make the mirror table rise and fall quickly and greatly when moving, so it can quickly adjust the distance between the objective lens and the specimen to make the object image appear in the field of vision. Generally, when using the low-power mirror, the coarse adjuster is used to quickly find the object image first.

② Fine adjuster (fine focusing spiral): a small spiral is used to weigh the fine adjuster, which can make the mirror table rise and fall slowly when moving. It is often used when using a high-power mirror, so as to get a clearer image and observe the structure of different layers and depths of the specimen.

◆ Lighting

Installed under the mirror table, including reflector , Light collector 。

(1) Reflector: It is mounted on the mirror base and can rotate in any direction. It has flat and concave surfaces and is used to reflect light from the light source to Condenser And then illuminate the specimen through the light hole, Concave mirror Strong light gathering effect, suitable for weak light, Plane mirror The light gathering effect is weak, and it is suitable for use when the light is strong.

(2) The light collector (condenser) is located on the light collector frame below the mirror platform, and is composed of Condenser And aperture, which is used to focus light on the specimen to be observed.

Microscope

① Condenser: It is composed of one or several lenses, which can converge the light line, enhance the illumination of the specimen, and make the light shine into the objective lens. There is an adjusting screw beside the mirror column, which can be rotated to raise and lower the condenser to adjust the field of vision Luminance The strength of Aperture (rainbow aperture) Opening Size of to adjust Amount of light 。

◆ Optical part

（1） eyepiece : Installed on the upper end of the lens barrel, usually 2-3 are available, and 5 ×, 10 × or 15 × symbols are engraved on them to indicate Magnification Generally, 10 × eyepiece is installed.

（2） objective lense : Installed on the rotator at the lower end of the lens barrel, there are generally 3-4 objective lenses, of which the shortest one with the symbol "10 ×" is a low-power lens, the longer one with the symbol "40 ×" is a high-power lens, and the longest one with the symbol "100 ×" is Oil mirror In addition, a circle of lines of different colors is often added on the high-power mirror and oil mirror to show the difference.

The magnification of a microscope is the product of the magnification of the objective lens and the magnification of the eyepiece. If the objective lens is 10 × and the eyepiece is 10 ×, the magnification is 10 × 10=100.

The length of microscope eyepiece is negatively correlated with the magnification, while the length of objective lens is positively correlated with the magnification. That is, the longer the eyepiece, the lower the magnification; The longer the objective lens is, the higher the magnification.

electron microscope structure

electron microscope By the mirror tube vacuum system And power cabinet. The mirror tube mainly includes electron gun 、 Electronic lens , sample rack Fluorescent screen And camera mechanism, which are usually assembled from top to bottom Cylinder ； The vacuum system is mechanically Vacuum pump 、 Diffusion pump and Vacuum valve And connected with the mirror cylinder through the air extraction pipeline. The power cabinet is composed of High voltage generator 、 excitation current Current stabilizer And various adjustments control unit form.

◆ Electronic lens

The electron lens is the most important part in the tube of the electron microscope. It uses a space electric or magnetic field symmetrical to the axis of the tube to Electron trajectory Bend to the axis to form focus, and its function is similar to that of glass Convex lens The effect of focusing light beam is similar, so it is called electronic lens. Most modern electron microscopes use Electromagnetic lens , the DC excitation current is very stable Polar boot The strong magnetic field generated by the coil of Electron focusing 。

◆ Electronic gun

The electron gun is made by Tungsten wire Thermionic cathode , grid and cathode. It can emit and form uniform velocity electron beam , so Accelerating voltage Of Stability It is required to be no less than 1/10000.

Imaging principle

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optical microscope

Principle of optical microscope

The optical microscope is mainly composed of eyepiece, objective lens, stage and reflector. Both eyepiece and objective lens are convex lenses with different focal lengths. The convex lens focal length of the objective lens is smaller than the convex lens focal length of the eyepiece. The objective lens is equivalent to Projector The object is inverted and magnified through the objective lens Real image 。 Eyepiece is equivalent to ordinary magnifier The real image is upright and magnified through the eyepiece Virtual image 。 Objects from the microscope to the human eye are inverted and magnified virtual images. Reflectors are used to reflect and illuminate the object being observed. There are generally two reflectors Reflector : One is a flat mirror, which is used when the light is strong; One is concave mirror, which can converge light lines when the light is weak.

electron microscope

SEM schematic diagram

Electron microscopical Resolution It is represented by the minimum distance between adjacent two points that it can distinguish. In the 1970s, Transmission electron microscope With a resolution of about 0.3 nm ( Discriminative ability Approx. 0.1 mm). Now the electron microscope is the largest Magnification More than 3 million times, and the maximum magnification of the optical microscope is about 2000 times, so the atoms and crystal Neatly arranged Atomic lattice 。

Maintenance of microscope

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Regular maintenance

(1) Moisture-proof If the room is wet, the optical lens is easy to mold Fogging 。 Once the lens is mouldy, it is difficult to remove it. The lens inside the microscope is not convenient to wipe, so it is wet harmfulness Larger. Mechanical parts It is easy to rust after being affected with damp. In order to prevent moisture, in addition to selecting a dry room, the microscope should be stored away from the wall, the ground and the wet source. One or two bags of silica gel shall be placed in the microscope box desiccant 。 And often bake the silica gel. After its color turns pink, it should be baked in time and used again after baking.

(2) The dust on the surface of the dust proof optical element not only affects the light passing, but also affects the optical system After zooming in, a large Stain , influence observation. Dust and sand particles falling into the mechanical part will also increase wear, which will cause movement obstruction and cause great harm. Therefore, the microscope must always be kept clean.

(3) The anti-corrosion microscope cannot be put together with corrosive chemical reagents. Such as sulfuric acid hydrochloric acid , strong alkali, etc.

(4) The purpose of heat protection is mainly to avoid Thermal expansion and cold contraction Causes the lens to open and fall off.

(5) Do not touch sharp objects, such as Nails , needle, etc.

(6) Please do not use it without permission.

Optical system wiping

At ordinary times, clean the surface of each optical part of the microscope with a clean brush or Mirror wiping paper Wipe it clean. When there is indelible dirt, oil stain or finger print on the lens, when the lens is mouldy, foggy and reused after long-term use, it needs to be wiped before use.

(1) The eyepiece and condenser lens can be disassembled for wiping. Due to the complex structure of the objective lens, the original accuracy can be restored only when it is assembled with a special instrument, so it is strictly prohibited to disassemble and wipe it.

Pay attention to the following points when removing the eyepiece and condenser lens:

a、 circumspect.

b、 During disassembly, mark the relative position (Available on the housing Scribing Mark), relative order and front and back of the lens to prevent mistakes during reassembly.

c、 The operating environment shall be kept clean and dry. When disassembling the eyepiece, just unscrew the upper and lower lenses from both ends. Intraocular field The light bar cannot be moved. Otherwise, the field boundary will be blurred. It is forbidden to further disassemble the upper lens after the condenser lens is unscrewed. Because the upper lens is Oil immersion It is well sealed when leaving the factory, and its sealing performance will be damaged if it is disassembled again.

Microscope

(2) Wiping method: Use a clean brush or blow ball to remove the dust on the lens surface. Then use a clean flannelette from Lens center Start working towards the edge Spiral One way movement. After wiping, change the flannelette to another place and wipe it until it is clean. If there is oil stain, dirt or fingerprint on the lens that cannot be wiped off, wrap a degreasing cotton with willow sticks and dip it with a small amount of alcohol and ether Mixed liquid (80% alcohol, 20% ether). If there is a heavier one Mildew spot Or when mold cannot be removed, it can be used Cotton swab Dip in water Stick it after wetting calcium carbonate Wipe with powder (more than 99%). After wiping, the powder shall be removed. Whether the lens is wiped clean, it can be used Reflected light Observe and check. It should be noted that the dust must be removed before wiping. Otherwise, the sand particles in the dust will scratch the mirror surface Furrow 。 No towel Handkerchief , clothes, etc. The alcohol ether mixture should not be used too much to prevent the liquid from entering the bonding part of the lens and degumming the lens. There is a layer of purple blue on the lens surface optical filming Do not wipe it off as dirt.

Wipe the mechanical part

The painted part of the surface can be wiped with a cloth. But alcohol, ether, etc. shall not be used Organic solvent Wipe to avoid Depainting 。 If there is rust on the unpainted part, it can be wiped off with a cloth dipped in gasoline. After wiping, apply protective grease again.

Mechanical device failure

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Coarse tuning Partial failure Exclusion of

The main fault of rough adjustment is that the tension is not uniform during automatic sliding or lifting. The so-called automatic sliding refers to the phenomenon that when the mirror cylinder, mirror arm or stage is stationary at a certain position, it will automatically and slowly fall down under the action of its own weight without adjustment. The reason is that the gravity of the mirror tube, mirror arm and stage itself is greater than Static friction Caused by. The solution is to increase the static friction force so that it is greater than the gravity of the mirror tube or mirror arm itself.

For inclined cylinder and most parts Binocular microscope For the coarse adjustment mechanism of, when the mirror arm automatically slides down, you can hold the stop pulley at the inner side of the coarse adjustment handwheel with both hands, and tighten both hands in a clockwise direction to stop the slide. If it doesn't work, you should find a professional to repair it.

The mirror tube slides down automatically, often giving people the illusion that it is caused by the loose fitting of gear and rack. So it's on the rack Add down shim. In this way, although the sliding of the mirror tube can be stopped temporarily, the gear and rack will be in an abnormal meshing state. As a result of the movement, the gear and rack are deformed. Especially when the cushion is not flat, the deformation of the rack is more severe. As a result, part of the rack is bitten tightly and part is bitten loosely. Therefore, this method should not be used.

In addition, as the rough adjustment mechanism has been out of repair for a long time, the lubricating oil will dry up, which will cause uncomfortable feeling when lifting, and even the friction sound of parts can be heard. At this time, the mechanical device can be disassembled for cleaning, greased and reassembled.

Troubleshooting of fine tuning part

The most common faults in the fine adjustment part are stuck and invalid. Fine tuning Partial installation Inside the instrument, its mechanical parts are small and compact, which is the most delicate and complex part of the microscope. The fault of fine adjustment part shall be repaired by professional technicians. Don't disassemble without enough assurance.

Troubleshooting of objective lens converter

The main fault of the objective lens converter is Positioning device malfunction. Generally, positioning leaf spring Damage (deformation, fracture, loss of elasticity, looseness of the fixed screw of the spring plate, etc.). When replacing a new spring plate, do not tighten the fixed screw for the time being, but first make optical axis correction according to "III (II) 2" in this section. etc. Shaft coupling Tighten the screws later. If the converter is of internal positioning type, the big head screw in the center of the rotating disk should be unscrewed, and the rotating disk should be removed before the positioning spring can be replaced. The method of optical axis correction is the same as the previous method.

Condenser Lifting mechanism Troubleshooting

The main failure of this part is also automatic sliding. The troubleshooting method is as follows:

(1) Straight tube microscope condenser Lifting mechanism ：1. 5. Celluloid Washer 2. Big head screw 3. Eccentric gear rod sleeve 4. Gear rod 6. Lifting hand wheel 7. When adjusting the double eye nut, use one hand with the double eye nut Wrench Insert it into the double eye nut on the end face of the handwheel, and use the other hand bolt driver Insert it into the notch of the big head screw at the other end, and tighten it with force to stop sliding.

(2) Lifting mechanism of inclined tube microscope condenser:

When adjusting, first use a screwdriver to withdraw the stationary screw 2 in the middle of the double eye nut for 1~2 turns, Bearing washer 3 is pressed and matched with the stationary screw 2, so it will also exit with it and separate from the end face of the gear rod 10. Then, use the double eye nut wrench to turn the double eye nut 1 to the adjusting seat 5 Precession 。 At the same time, use the other hand to rotate the hand wheel for the test, until the lifting mechanism is properly tightened and can stay at any position, then stop screwing in the double eye nuts. Finally, screw the stationary screw in again to make the bearing washer contact the gear rod 10.

This adjustment can eliminate the fault because the adjustment seat 5 Inner hole It is tapered. The tapered shaft sleeve 4 is located in the axial There are notches. When the double eye nut 1 is screwed inward, push the conical sleeve inward, so that when the conical sleeve is moving forward, the notch becomes smaller, the inner hole shrinks, and the gear rod 10 is clamped more tightly, increasing the gear rotation Frictional resistance To stop the automatic descent.

Troubleshooting

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1. Self sliding of mirror tube

This is Biological microscope One of the frequent faults. about axle sleeve The solution of the microscope with the type structure can be carried out in two steps.

Step 1: Hold the two with both hands Coarse tuning handwheel , tighten with relative force. See whether the problem can be solved. If the problem cannot be solved, use a special double column wrench to unscrew a rough adjustment handwheel and add one piece The friction plate After the hand wheel is tightened, if it is hard to rotate, the added friction plate is too thick, and a thin one can be replaced. It shall be subject to that the handwheel can be rotated effortlessly, and the mirror cylinder can move up and down easily without sliding down by itself. Scrap of friction plate Photographic negative And less than 1mm thick Soft plastic Sheet punch Punching 。

Step 2: Check the gear on the rough adjustment handwheel shaft and the mirror cylinder rack Engagement status. The up and down movement of the mirror tube is completed by the gear driving the rack. The best meshing state of gear and rack is theoretically the indexing of rack Line and Geared Dividing circle Tangency. In this state, the gear rotates easily and wears the rack most? There is a wrong way to add shim Make the rack tightly press the gear to prevent the mirror tube from sliding down. At this time, the indexing line of the rack intersects the indexing circle of the gear, and the tooth tips of the gear and the rack firmly support each other's tooth roots. When the gears rotate, serious grinding will occur between them. As the rack is made of copper, the gear is made of steel. Therefore, grinding each other will damage the teeth on the rack, and a lot of copper filings will be generated on the gear and rack. The last rack will Severe wear And cannot be used. Therefore, the rack must not be padded to prevent the mirror tube from sliding down. To solve the problem of self sliding of the mirror tube, only the large coarse adjustment handwheel and eccentric shaft sleeve can be used friction To achieve. However, there is one exception, that is, the indexing line of the rack is away from the indexing circle of the gear. At this time, when turning the coarse adjustment handwheel, the phenomenon of idling and slipping will also occur, affecting the up and down movement of the mirror cylinder. If this is done by adjusting the eccentric shaft sleeve of the rough adjustment handwheel, the meshing distance between the gear and the rack cannot be adjusted. The problem can only be solved by padding a proper sheet behind the rack. The standard for shimming to adjust the engagement distance between gear and rack is that it is not difficult to rotate the rough adjustment hand wheel, but it does not idle.

After adjusting the distance gear Add some neutral grease to the rack. Let the mirror tube move up and down a few times. Finally, tighten the two compression screws on the eccentric shaft sleeve. Otherwise, when turning the rough adjustment handwheel, the eccentric shaft sleeve may rotate with it, and the rack will be stuck, making the mirror can not move up and down. At this time, if the force of turning the rough adjusting handwheel is too large, the rack and eccentric shaft sleeve may be damaged. After tightening the compression screw, if the eccentric shaft sleeve still rotates with it. This is because the thread of the screw hole of the compression screw is not properly modified. Because manufacturers change threads with machines, one or two threads are often not changed in place. At this time, even if the pressing screw cannot be screwed in place, the eccentric shaft sleeve cannot be pressed tightly. If this fault is found, it can be solved by tapping the thread of the screw hole with M3 tap.

After the above steps are completed one by one, the problem of self sliding of the mirror tube will be solved.

2. The sunshade positioning fails

It may be that the fixing screw of the sunshade is too loose, and the locating marble escapes Locating hole Cause. Just put the marble back into the locating hole and tighten the fixing screw. If the sunshade is difficult to rotate after tightening, it is necessary to Sunshade Add a washer between the loading platform and the loading platform. After the thickness of the washer is tightened with screws, the sunshade can rotate easily, the locating marbles can not escape, and the sunshade should be positioned correctly.

3 The objective lens converter has difficulty in rotating or positioning

The converter may be difficult to rotate because the fixing screws are too tight. Make it difficult to rotate and damage parts. If it is too loose, the inner bearing marbles will be off the track and squeezed together, which also makes it difficult to rotate; In addition, marbles are likely to come out. The diameter of marbles is only one millimeter, which is easy to lose. The tightness of the fixing screws shall be subject to the ease of rotation of the converter and no looseness in the vertical direction. After adjusting the fixing screw, lock it immediately Screw lock Tight. Otherwise, problems will occur again after the converter rotates.

Converter positioning failure may sometimes be positioning reed Broken or elastic deformation Caused by. Generally, only the reed needs to be replaced.

4 The lens of the eyepiece objective is polluted or Mildew

After most microscopes are used for a period of time, the outside of the lens will be contaminated or mildewed. in especial High power objective 40X, it is very easy to be polluted by sugar liquor when doing the experiment of "Observation of the Separation and Restoration of Plant Cell Plasma Wall". If the lens is polluted and not cleaned in time, mildew will occur. The treatment method is to use clean and soft Silk cloth Dip in warm water to clean off pollutants such as sugar solution, then dry with dry silk cloth, and then Long fibre Absorbent cotton Dip in some lens cleaning fluid for cleaning, and then dry it with a hairdryer. It should be noted that the cleaning solution must not penetrate into the objective lens. Because in order to achieve the required magnification, the lens of the high power objective needs to be tight Glue Join together. The glue is transparent and very thin Ether After the solvent is dissolved, the light path will change when the light passes through the two lenses. The observation effect will be greatly affected. Therefore, do not allow alcohol, ether and other solvents to penetrate into the interior of the objective lens during cleaning.

If the lenses inside the eyepiece and objective lens are contaminated or mildewed, they must be disassembled for cleaning. The eyepiece can be directly unscrewed and removed for cleaning. However, the structure of the objective lens is more complex Stacking The distance between each lens has very strict requirements, and the precision is also very high. The manufacturer is positioned after precise calibration during assembly. Therefore, after disassembly and cleaning, it must be assembled in strict accordance with the original.

The lens of biological microscope is used Precision machining Past optical glass In order to increase Transmittance , a thin layer of optical filming 。 In this way, the light transmittance can reach 97% - 98%. The surface of the transparent film is smooth and thin Abrasions If there are traces left, its light transmittance will be greatly affected. It will become blurred during observation. So when wiping the lens, be sure to use a clean soft silk cloth or a clean brush to gently wipe it Mirror wiping paper Wipe gently to avoid damaging the transparent film.

5 The mirror frame cannot be fixed when the mirror hip is tilted

This is caused by the looseness of the connecting screws between the mirror frame and the base. You can use a special double ended wrench or use a pointed nose pliers to clamp the two eyelets of the double eye nuts and tighten them with force. If the problem is not solved after tightening, the nut shall be padded with appropriate gasket.

When the image on the display screen is cut, it is necessary to consider whether the pull rod moves in place; If it is not in place, move the corresponding pull rod to the right place.

6 Dirty spots found during use

If the image on the display screen has dirty spots, it is necessary to consider whether there is dirt in the specimen room. If there is no dirt in the specimen room, check the surface of the objective lens again to see if there is dirt. If there is dirt, the display screen will show dirty spots. The solution is also simple. Just remove the dirt on the surface of the objective lens and in the specimen room.

7 The image is not clear when adjusting the zoom

If the image is not clear when adjusting the zoom, check whether the high power zoom is clear. If not, just set it to the highest power and refocus.

usage method

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Use of microscope

utilize Natural light source During the microscopic inspection, it is better to use the light source facing north rather than direct sunlight; utilize Artificial light source Should be used Fluorescent lamp The light source of.

During the microscopic examination, the body should face the practice platform, adopt a correct posture, open the eyes naturally, observe the specimen with the left eye, observe the record and draw with the right eye, and adjust the focus with the left hand to make the object image clear and move the field of vision of the specimen. Record and draw with the right hand.

The stage cannot be tilted during microscopic examination, because when the stage is tilted, liquid or oil is easy to flow out, which not only damages the specimen, but also pollutes the stage and affects the examination results.

During microscopic examination, the specimen should be moved in a certain direction until the whole specimen is observed, so as not to miss or repeat.

The microscope focuses on the light, the conversion of the lens and the adjustment of the light. observation parasite The light regulation is very important for specimens. Because the observed specimens, such as worm eggs Cyst Etc. are Natural light Objects in different states are large and small, dark and light, colorless and transparent, and Low magnification . High power lenses have more conversions, so the focus and light need to be adjusted at any time according to different specimens and requirements during microscopic examination, so as to make the observed image clear. In general, the light of dyed specimens should be strong, and the light of colorless or unstained specimens should be weak; The light should be weak at low power and strong at high power.

1. Aiming:

(1) Turn the low-power mirror to the lower part of the lens barrel to be in line with the lens barrel.

(2) Turn the reflector to adjust the field of vision to the brightest without shadow. The reflector has flat and concave surfaces. When the light source is strong, use the flat surface. When the light source is dark, use the flat surface concave When strong light is needed, raise the condenser and enlarge the aperture; When weak light is needed, lower the condenser or reduce the aperture appropriately.

(3) Place the specimen to be observed on the stage, and rotate the coarse adjuster to lower the lens barrel until the lens is close to the specimen. While rotating the coarse adjuster, lean over the mirror and carefully observe the distance between the lens and the specimen.

(4) Left eye at Eyepiece Observe, at the same time, turn the left hand for coarse adjustment, make the lens barrel rise slowly to adjust the focus, so that the objects in the field of vision will stop when they see the top, and then adjust the micro adjuster until the specimen is clear.

2. Use of lens and adjustment of light:

The microscope generally has three lenses, namely low power, high power and oil lens, which are fixed on the conversion plate of the lens In hole 。 When observing the specimen, use a low-power lens first. At this time, the field of vision is larger, and the specimen is easier to find, but the magnification is smaller (generally 100 times). It is difficult to observe the structure of smaller objects. High multiplexer Objective magnification Large magnification (generally 400 times), able to observe small objects or structures.

Parasitic worm Eggs, Microfilaria ， protozoan Of Trophozoite And cysts, insect Of larva , both low and high power mirrors are used. Histiocyte For protozoa inside, use oil lens. Observe with low and high power mirrors. If the object or its internal structure can not be accurately identified under low power mirrors, turn to high power mirrors for observation. Observe with oil lens. Generally, dip the oil lens directly into the oil drop after adding a drop of oil for microscopic observation.

3. Identification of low-power, high-power and oil lens:

(1) Mark the magnification of 10 ×, 40 ×, 100 ×, or 10/0.25, 40/0.65100/1.25.

(2) The low-power mirror is the shortest, the high-power mirror is the longest, and the oil mirror is the longest.

(3) The lens hole in front of the lens has the largest low-power lens, the larger high-power lens and the smallest oil lens.

(4) The oil lens is often engraved with black Color ring Circle, or "oil" word.

4. Use method of changing low power mirror to high power mirror:

(1) After the light is aligned, move the propeller to find the specimen to be observed.

(2) If the size of the specimen is large, and its structure cannot be clearly seen, so it cannot be confirmed, move the specimen to the center of the field of vision, and then rotate the high-power lens under the lens tube.

(3) Rotate the spinner until the image is clear.

(4) Adjust the condenser and aperture to make the objects in the field of vision reach the clearest degree.

5. Usage of oil lens:

(1) Principle: When using the oil lens for observation, it is necessary to add asphalt, because the oil lens needs more light to enter the lens, but the air hole of the oil lens is the smallest, so the light entering the lens is less, and the object is not easy to see clearly. At the same time, the light transmitted from the slide is refracted due to the different density of the medium (slide air lens) (slide: n=1.52, air: n=1.0) astigmatism Therefore, there is less light coming into the lens, and objects are more difficult to see. So we use a glass slide Refractive index A similar medium, such as asphalt, is added between the specimen and the slide to keep the light from passing through the air, so that more light can be emitted into the lens and the image can be seen clearly.

(2) Use of oil lens:

a. Turn the light to its maximum (the condenser is raised and the aperture is fully open).

b. Rotate the coarse adjuster to make the lens tube rise, and drop 1 small drop of asphalt (not too much, not spread) on the specimen directly below the lens.

c. Turn the transfer plate of the lens so that the oil lens is under the lens barrel.

d. When leaning over the side beside the mirror and observing with the naked eye, rotate the coarse adjuster to make the oil lens slowly drop into the cedar oil and gently touch the glass slide.

e. Slowly rotate the coarse adjuster to make the oil lens slowly rise until the object image of the specimen is seen.

f. Turn the micro adjuster to make the visual field image reach the clearest degree.

g. Slowly move the thruster with the left hand, and turn the spinner to observe the specimen.

h. After observing the specimen, rotate the coarse adjuster to raise the lens tube and take down the specimen slide. Immediately wipe the cedar oil on the lens with lens wiping paper.

6. Precautions:

(1) Before using the microscope, you should be familiar with the name of each part of the microscope and the use method, especially the characteristics of the three kinds of lenses.

（2） Parasitology Most of the specimens observed in the practice are colorless and light in color, so attention must be paid to the adjustment of light.

(3) When observing fresh specimens, cover slides must be added to prevent the specimens from drying and deformation due to evaporation or contamination and erosion of the lens. At the same time, the surface of the specimens can be even and the light can be concentrated, which is conducive to observation.

（3） Maintenance of microscope

1. When the microscope is taken out of the wooden box or packed, hold the mirror arm tightly with the right hand, and hold the mirror base with the left hand, and take it out gently. Do not use only one hand to pick up the microscope, so as to prevent it from falling, and then put it gently on the practice platform or into a wooden box.

2. When the microscope is placed on the practice platform, first place one end of the mirror base, and then place all the mirror bases firmly. The mirror base must not be in full contact with the platform at the same time, so that the vibration is too large, and the lens and the micro regulator devices are easily damaged.

3. The microscope must always be kept clean and free from oil stain and dust. If the lens is dirty, gently wipe it with lens wiping paper. If there is oil stain, dip the lens wiping paper slightly xylene Wipe off.

4. The microscope shall not be exposed to the sun and used.

5. The eyepiece and the eyepiece should not be taken out and removed randomly. When the eyepiece must be taken out, the lens cylinder should be Upper mouth Cover with cloth to avoid dust falling into the lens barrel. When replacing the contact lens, it should be placed upside down under the clean table after removal, and then put into the tube for placing the contact lens in the wooden box.

6. After the microscope is used up, take down the specimen, lower it through the condenser, then turn the objective lens into an "eight" shape, and turn the coarse adjuster to lower the lens barrel, so as to avoid the contact between the lens and the condenser.

7. The microscope should be placed in a dry place to prevent mildew.

2、 Use of stereomicroscope

Stereomicroscope can obtain Stereoscopic feeling The principle of perception is due to the image formed on the omentum of the human eye from different directions through two eyepieces. The microscope has dual tubes inclined at 45 °, through which the upright three-dimensional image in a wide field of vision can be observed. Where there is a sight adjustment ring on the right eye lens cylinder, such as Observer The binocular vision is different. You can first adjust the microscope to make the left eye image clear, and then rotate the right vision adjustment circle to make the right eye image clear. The two cylinders can be rotated relatively within a certain angle to adapt to the distance between the workers' eyes. Microscopical Working distance 100mm, and there are handwheel It can be rotated, and the microscope magnification can be changed without changing the working distance. For the reading of the total magnification of the microscope, when using a 25 × eyepiece, the number on the right dial shall prevail; when using a 6.3 × eyepiece, the number on the left dial shall prevail.

3、 Use and maintenance of other instruments and equipment

Parasitology except microscope and stereomicroscope Internship There are still many equipment and instruments used, and we will not repeat them here. The tutor will introduce them to us in each practice class Classification Slightly Operating principle Introduction to.

(I) Glassware Equipment: handle with care when using to prevent breakage, and clean after use Cool dry Drying to prevent mildew.

（2） Metal instruments and equipment: do not touch or touch less acidic and alkaline articles. After use, wash, wipe, dry and dry them to prevent corrosion rust

How to use low-power mirror

(1) Take out and place the microscope: the microscope is usually stored in the cabinet or box, and taken out from the cabinet when used. Hold the mirror arm tightly with the right hand, hold the mirror base with the left hand, and place the microscope on the test bench in front of your left shoulder. The rear end of the mirror base is 7cm away from the table edge, which is convenient for operation.

(2) Light alignment: move the rotator with your thumb and middle finger (never move the objective lens with your hand), so that the low-power lens is aligned with the light hole of the mirror platform (when you hear the knocking sound when rotating, it means that the optical axis of the objective lens is aligned with the center of the lens barrel). Adjust it to a larger aperture and turn the reflector to the light source. Observe the left eye on the eyepiece (the right eye is open), and adjust the deflection angle of the reflector at the same time until it is bright in the field of vision facula until.

(3) Placement of slide specimen: take a slide specimen and place it on the mirror stand, and make sure there is Cover slide The side of the slide is upward, and it must not be placed upside down. Clamp it with the slide holder, and then move the slide to adjust the part to be observed to the field of vision.

(4) Adjust focus: press with left hand counter-clockwise direction Rotate the coarse focusing screw to slowly lower the lens barrel to about 5mm from the objective lens to the specimen. When lowering the lens barrel, do not observe it on the eyepiece. Be sure to look at the lens barrel from the right side to lower it, so as not to damage the lens or specimen due to excessive lowering. Then, open both eyes at the same time, observe with the left eye on the eyepiece Clockwise Slowly rotate the fine focusing screw to slowly lower the lens barrel until a clear image appears in the field of vision.

(5) Adjustment visible image Position: If the object image is not in the center of the field of vision, move the slide to adjust the part to be observed to the field of vision. (Note that the moving direction of the slide is opposite to the moving direction of the object in the field of vision.). If the brightness in the field of vision is not appropriate, it can be adjusted by adjusting the size of the aperture. If the lens table has dropped more than the working distance (>5.40mm) when adjusting the focal length and no object is seen, it means that this operation failed, and it should be re operated. Do not rise the lens table in a hurry blindly.

How to use high-power mirror

(1) Select the target: you must first adjust the part to be further observed to the center under the low power lens, and at the same time adjust the image to the clearest degree, then you can observe it with the high power lens.

(2) Lens conversion: rotate the converter to replace the high-power lens. When converting the high-power lens, rotate slowly and observe from the side (to prevent the high-power lens from colliding with the glass slide). If the high-power lens touches the glass slide, it means that the focus of the low-power lens is not adjusted properly and should be re operated.

(3) Adjust the focal length: after changing the high power lens, observe with the left eye on the eyepiece. At this time, you can generally see an unclear image anti-clockwise Move about 0.5-1 circle to get a clear image (do not use a coarse adjuster!)

(4) Adjust the brightness: If the brightness of the field of vision is not appropriate, you can adjust it with a light collector and aperture.

(5) Replacement of slide specimen: If the slide specimen needs to be replaced Clockwise (Do not turn in the wrong direction) Turn the coarse adjuster to lower the lens table before taking down the slide specimen.

matters needing attention

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When holding the mirror, you must hold the arm with your right hand and the bracket with your left hand. Do not pick up the mirror with one hand to avoid parts falling off or hitting other places.

Microscope in Hooke Era

Handle with care. Do not place the microscope on the edge of the test bench. It should be placed 10cm away from the edge to avoid falling to the ground.

Keep the microscope clean. The optical and lighting parts can only be used Mirror wiping paper Wipe, avoid mouth, blow, wipe or use Cloth eraser Wipe the mechanical part with cloth.

Do not touch the lens and Mirror stand , if contamination Wipe it with mirror wiping paper immediately.

place slide The specimen should be aligned with the center of the light hole, and the slide should not be placed reversely to prevent crushing or damaging the slide objective lense 。

Develop the habit of observing with both eyes open at the same time, observing the field of vision with the left eye and drawing with the right eye.

Do not take it off at will eyepiece To prevent dust from falling into the objective lens, do not disassemble various parts at will to prevent damage.

After use, it must be restored before being put back into the mirror box. The steps are: take down the specimen and rotate Rotator Move the lens away from the light hole, lower the mirror table and lay it flat reflector , Down Light collector (but do not touch the reflector), close the aperture, return the sheet pusher, and cover Silk cloth And the outer cover, and put them back into the cabinet of the test bench. Finally fill in and use a registration form 。 (Note: The reflector is usually placed vertically, but sometimes because the collector is not raised to the proper height, the aperture will be damaged when the mirror platform descends, so it is placed horizontally instead).

Cause of fault

1、 The calibration method is to place the standard scale on the Hardness tester (or microscope), adjust the focal length first to make it within the eyepiece field of vision or Projection screen The scale of the standard scale can be clearly seen on the top, and adjusted to coincide with the scale in the eyepiece, then Reading microscope Compared with the marking of standard marking ruler measuring range 5 intervals, compare each interval for 3 times, and take the average value , which relative error W is calculated according to the following formula:

W =( Li - L )/ L ×100%

Where: W ——Relative error (mm); Li —— Reading microscope The measured length of the comparison section of (mm)（ i =1～5)； L ——The actual length of the comparison section of the standard scale (mm).

The calibration of the reading microscope shall be compared section by section according to the above method, and the error shall not be greater than ± 0.5%.

2、 Fault causes and repair

1. Microscope turbid

Main reason: the lens is dirty or moldy.

Troubleshooting: When there is dust or dirt on the lens, remove it with a brush or feather, and then use Lens paper Or with Absorbent cotton Dip a little Absolute alcohol or Ether Carefully wipe along the circular path, but do not let the wiping liquid lose.

2. Can't see clearly in the mirror indentation edge

Main reason: some lenses are loose.

Troubleshooting: retighten the loose parts of the lens.

3. Reading microscope scale value and Standard ruler Scale misalignment

Main reasons: the objective lens is loose or the gasket at the connection between the objective lens and the lens barrel is lost, and the focal length changes.

Troubleshooting: fasten the lens of the objective lens. If the washer is lost, its thickness should be adjusted repeatedly, and a suitable washer should be equipped until the position with the smallest scale error.

4. The scale value of reading microscope is larger than that of standard ruler

Main reason: The growth of the lens tube may be due to the loose joint of the lens tube.

Troubleshooting: Retighten the lens tube connector.

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