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Use of the microscope
Jun 20, 2018

When using a natural light source for microscopy, it is best to use a light source that faces the north, and it is not appropriate to use direct sunlight; when using an artificial light source, it is preferable to use a fluorescent light source.

When the microscope is inspected, the body must take a correct posture. The two eyes open naturally. The left eye observes the specimen and the right eye observes the recording and drawing. At the same time, the left hand adjusts the focal length to make the object image clear and move the specimen's field of vision. Right hand record, drawing.

During microscope inspection, the stage can not be tilted, because when the stage is tilted, the liquid or oil flows out easily, which not only damages the specimen but also contaminates the stage, and also affects the inspection result.

During the microscopic examination, the specimen should be moved in a certain direction until the observation of the entire specimen is completed, so as not to miss the examination and not repeat.

The light of the microscope is the light, the conversion of the objective lens and the adjustment of the light. Light regulation is important when viewing parasite specimens. Because the observed specimens, such as eggs, cysts, etc., are all objects in the natural light state. They are large, small, dark and light, some are colorless and transparent, and low magnification and high power contact lenses have more conversions. With different specimens and requirements for microscopic examination, the focal length and light need to be adjusted at any time so that the observed objects can be seen clearly. Under normal circumstances, stained specimens should be strong light, colorless or unstained specimens should be weak light; low magnification observation light should be weak, high magnification observation of light should be strong.

1. Light:

(1) Turn the revolver below the lens barrel in line with the lens barrel.

(2) Slide the mirror and adjust to the brightest and shadowless field of view. The reflector has flat and concave sides. When the light source is strong, the flat surface is used. When the light source is dark, the concave surface is used. When a strong light is required, the condenser is increased and the aperture is enlarged. When the low light is required, the condenser is reduced or the aperture is appropriately reduced.

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

(4) The left eye is observed with the eyepiece, while the left hand is rotated to make coarse adjustment, so that the lens barrel gradually rises to adjust the focal length, so that the object within the visual field is stopped when it is seen, and then the micro-adjuster is adjusted until the specimen is clear.

2. Use of the objective lens and light adjustment:

The microscope generally has three contact lenses, namely low magnification, high magnification and oil mirror, fixed in the hole of the conversion lens of the contact lens. When observing the specimen, use the low power contact lens first. At this time, the field of view is larger and the specimen is easier to detect. However, the magnification is small (usually 100 times magnification), and the smaller object is not easy to observe the structure. High power contact lens magnification is larger (typically 400 times magnification) and can observe tiny objects or structures.

Parasite worm eggs, microfilariae, protozoa trophozoites and cysts, insect larvae, are used low, high power microscope. The protozoa within the tissue cells use oil mirrors. Use low-power, high-power lens observations, such as the low magnification can not be accurately identified when the object or its internal structure, the high magnification observation. Observe with the oil mirror, generally add a drop of oil directly after the oil lens immersed in oil droplets for microscopic observation.

3. Low magnification, high magnification, oil lens identification:

(1) Mark the magnification 10x, 40x, 100x, or 10/0.25, 40/0.65, 100/1.25.

(2) The low magnification lens is the shortest, the high magnification lens is long, and the oil mirror is the longest.

(3) The lens aperture in front of the lens is the largest, the high magnification lens is large, and the oil mirror is the smallest.

(4) The oil lens is often engraved with black rings or "oil" characters.

4. How to change the low magnification lens to high magnification:

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

(2) If the volume of the specimen is large and the structure cannot be clearly seen and cannot be confirmed, move the specimen to the center of the field of view and rotate the high magnification objective lens below the lens barrel.

(3) Rotate the micro-adjuster until the object is clear.

(4) Adjust the condenser and aperture so that the objects in the field of vision reach the sharpest level.

5. Use the oil mirror:

(1) Principle: When using the oil mirror to observe, you need to add cedar oil, because the oil mirror needs to enter the lens of light, but the oil mirror's ventilation hole is the smallest, so that the light entering is less, the object is not easy to see clearly. At the same time, refracted astigmatism occurs due to the difference in the medium (slide-air-contact lens) density (slide: n = 1.52, air: n = 1.0) due to the light transmitted from the slide, so the light that enters the lens Even less, objects are less visible. A medium similar to the refractive index of the slide glass, such as cedar oil, is then applied between the specimen and the slide so that the light does not pass through the air, so that more light enters the lens and the object image is seen clearly.

(2) Use of oil mirror:

a. Adjust the light to the maximum level (the condenser is raised and the aperture is fully open).

b. Turn the coarse adjuster to raise the lens tube. Drop 1 small drop of tar oil (not too much, do not apply) on the specimen just below the objective lens.

c. Rotate the objective lens adapter plate so that the oil lens is below the barrel.

d. Observe the side of the mirror while observing the naked eye. Turn the coarse adjuster so that the oil lens slowly descends and dipped into the tarmac, gently touching the slide.

e. Slowly rotate the coarse adjuster so that the oil lens slowly rises until the specimen image is seen.

f. Rotate the micro-regulator to achieve the sharpest visual image.

g. Slowly move the propeller with your left hand and turn the micromanipulator to observe the specimen.

h. After the specimen is observed, rotate the coarse adjuster to raise the lens barrel and remove the specimen slide. Clean the tar oil on the lens immediately with a lens paper.


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