How to use a microscope

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How to use a microscope

1. Preparation before observation

(1) place the microscope on a stable experimental platform, and the distance between the mirror base and the edge of the experimental platform is about an inch. The posture of the microscopic examiner should be correct. Generally, the left eye is used for observation, and the right eye is convenient for drawing or recording. Both eyes must be opened at the same time to reduce fatigue. You can also practice observing with both left and right eyes. See the right figure for the microscope structure

(2) the microscope is an optical precision instrument, so you should be very careful when using it. Before using it, you should be familiar with the structure and performance of the microscope and check whether the total parts are intact. Whether there is dust on the lens body, whether the lens is clean, and do necessary cleaning and adjustment work

(3) when adjusting the light source, avoid direct light source, because the direct light source affects the clarity of the object image, damage the light source, and then clamp the device and lens at the other end of the test piece in the same way, and stimulate the eyes. In sunny days, the scattered light outside the window can be directly used. In bright and dark weather, 8-30w fluorescent lamp or microscope lamp can be used for illumination.

general steps for adjusting the light source and illumination:

rotate the low power objective lens to the lower part of the lens barrel, and rotate the coarse adjusting wheel to make the distance between the lens and the stage about 0.5cm

raise the concentrator so that it is as high as the surface of the stage. Otherwise, the light line is dark when using an oil mirror

look at the eyepiece with the left eye and adjust the mirror angle of the reflector (the reflector has concave and flat sides, and the natural light source with strong light should use a flat mirror; the natural light source or artificial light source with weak light should use a concave mirror.) Aiming at the light, the whole field of vision is the brightness of the technology that reaches the world's first-rate level in product quality, material consumption, energy consumption and "three wastes" emission. When inspecting stained specimens, the light should be strong; The light should not be too strong when examining undyed specimens. The light can be adjusted by enlarging or reducing the aperture, lifting the concentrator, and rotating the reflector.

2. Observe with a low power mirror

the specimen examined must be observed with a low-power mirror first, because the low-power mirror has a large field of vision, which is easy to find the target and determine the location of the examination

(1) first place the specimen slide on the stage, place the specimen directly below the objective lens, turn the coarse adjusting wheel, lower the objective lens or raise the stage so that the objective lens reaches 0.5cm of the specimen

(2) look at the eyepiece with the left eye, and slowly rotate the coarse adjusting wheel counterclockwise. When the object image appears in the field of vision, use the fine adjusting wheel and rotate it slightly up and down until a clear object image is obtained in the field of vision. Then carefully observe each part of the specimen, determine and move the part to be further observed to the center of the field of vision, and prepare to observe with a high-power microscope

3. High power microscopic observation

turn the high-power lens to the right below. When changing the objective lens, you need to observe with your eyes on the side to avoid the collision between the lens and the glass slide. Then observe through the eyepiece, carefully adjust the aperture and the condenser to make the brightness of the light appropriate, and carefully turn the fine adjustment wheel in the positive and negative directions until a clear image is obtained, so as to find the most suitable part for observation. Move the part to be further observed to the center of the field of vision, and prepare to observe with an oil lens

4. Oil lens observation:

(1) raise the concentrator, fully open the rainbow aperture

(2) lift the lens barrel or lower the stage with the coarse adjusting wheel, turn the converter to turn the oil lens directly below the lens barrel. Drop a drop of tar on the microscopic part of the slide specimen. Slowly turn the coarse adjusting wheel clockwise with your right hand to lower the lens barrel or raise the stage. At the same time, observe from the side of the microscope and immerse the oil lens in the oil until it is almost in contact with the specimen. Be careful not to press the specimen to avoid crushing the glass slide and even damaging the oil lens

(3) observe from the eyepiece, further adjust the light, and the line can be seen from the top to make the light bright. Then use the coarse adjusting wheel to slowly raise the lens barrel or slowly lower the stage until the object image appears in the field of vision, and then use the fine adjusting wheel to correct the focal length. If the oil lens has left the oil surface and there is still no object image, you must observe it from the side again, lower the oil lens, and repeat the operation until the object image is clear

5. Film change

after observing one specimen, if you want to observe another specimen, you need to first turn the high-power objective lens (or oil filter lens) back to the low-power objective lens, take out the specimen, and replace it with a new film according to the method of placing the film, then you can observe. Never change the film under the high-power objective lens (or oil lens) to prevent damage to the lens

II. Maintenance of microscope

(1) after the oil lens is used, wipe the oil on the lens with lens wiping paper, then take a piece of lens wiping paper, drip a small amount of xylene for wiping, and then take another piece of new lens wiping paper to wipe the residual xylene on the lens. Otherwise, the glue of the bonded lens will be dissolved by xylene, and the lens is easy to shift and fall off over time

(2) lower the concentrator, open the rainbow aperture, and make the reflector perpendicular to the mirror base to avoid dust accumulation

(3) wipe the mirror body with silk cloth (never wipe it by hand) to remove dust, oil and water vapor, so as to avoid rust and mildew

(4) restore all parts of the microscope to their original positions, lower the lens barrel, place the objective lens on the stage in an splayed shape, and then return the microscope to the lens box

(5) the microscope should be stored in a dry and cool place, not exposed to strong sunlight. Desiccant (silica gel) should be placed in the microscope box in the season of mildew and rain. If it is not used for a long time, the optical part should be unloaded in the dryer to avoid dampness and mildew

(6) the microscope should not be placed with volatile drugs or corrosive drugs, such as iodine tablets, hydrochloric acid, sulfuric acid and other drugs

III. precautions

1. When taking the microscope, you must hold the mirror arm with one hand and the mirror base with the other hand, and keep the upper and lower parts of the mirror vertical. You should avoid vibration and put it on the stage gently. Never lift it with one hand to prevent the microscope, reflector and eyepiece from falling

2. Wipe the lens body once before use, and wipe the lens with lens wiping paper (never wipe with fingers). If there is dry asphalt on the stage or lens, wipe it off with a small amount of xylene with lens wiping paper

3. If the microscope is found to be inflexible or damaged during use, do not disassemble and repair it without authorization, and immediately report it to the instructor for treatment

4. Pay attention to protect the lens and do not crush the specimen quilt. Check whether the grounding device is a normal piece and damage the lens

5. After the microscope is used, register the microscope use card and put it back into the mirror box after being checked by the instructor

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