How to Use Oil Mirror of Biological Microscope Correctly
(1) After finding the specimen with a low-power objective lens, switch to a high-power objective lens for observation, move the specimen to the center of the field of view, place the diaphragm at the big place of zui, lift the lens barrel by about 1.5cm (or lower the stage by 1.5cm), and turn the objective lens away from the optical axis.
(2) Take down the specimen piece, drop 1 or 2 drops of fragrant tar on the lens plane at the upper end of the condenser, and then put the specimen piece back in its original position, so that the bottom of the glass slide is in close contact with fragrant tar to prevent gas saturation in the oil. But in normal operation, this step can be omitted.
(3) Drop a drop of fragrant tar on the cover glass or the part required to be observed by the smear specimen, switch the oil mirror to the optical axis, and adjust the coarse focusing screw with special care to make the lens slowly descend, carefully observe the distance between the front end of the oil mirror and the specimen, and stop descending when the front end of the oil mirror starts to touch the oil droplets. This operation process must be very careful to prevent the oil lens from crushing the specimen and damaging the oil mirror.
(4) Observe from the eyepiece with the left eye, and adjust the fine-tuning focal screw with the right hand, so that the lens can slowly focus to the correct working distance to see the specimen image clearly. Please note: Don't make mistakes in coarse and fine-tuning the focal screw. Cover glass should be thin, and it can't be focused if it is too thick, otherwise it will easily crush the specimen and damage the lens.
(5) Adjust the size of the diaphragm to make the numerical aperture of the condenser match the oil mirror to obtain a clear image. ’
(6) After observation, do a good job of cleaning in time. First, raise the oil mirror to a distance of 1.5 cm from the specimen, turn the oil mirror away from the optical axis, gently absorb the oil on the oil lens with dry mirror-wiping paper, then wipe it twice with xylene-soaked mirror-wiping paper, and use it after zui.
Wipe the clean mirror paper lightly for 2 or 3 times. Wipe off the oil drops on the condenser in the same way. The fragrant asphalt on the specimen can be wiped clean by paper-pulling method, that is, a small piece of mirror-wiping paper is used to cover the oil droplets on the specimen, and then some xylene is dropped on the paper, and the paper is pulled out while wet, so that it can be wiped clean for 3 or 4 times in a row without damaging the smear specimen. Precautions for using oil mirror:
(1) When the oil mirror is temporarily suspended, the lens barrel should be raised to turn the objective away from the optical axis, so as to prevent the lens barrel from sliding and crushing the specimen and damaging the condenser and oil mirror.
(2) After use, wash the fragrant asphalt in time, because the fragrant asphalt is easy to stick dust in the air, and it may wear the lens when scrubbing after sticking dust. In addition, the fragrant asphalt is not easy to clean after being dried in the air, and it will corrode, accumulate dust and
Mildew, fog and other hazards occur, so it must be wiped thoroughly in time.
(3) When using the oil mirror, the same height focusing operation is generally not carried out, because the same height focusing is only applicable to the original objective lens of each microscope. If the thickness of the specimen is too thick, the conversion oil mirror may encounter the glass slide when focusing at the same height.
In addition to fragrant asphalt as oil immersion medium, water can also be used as medium, which is suitable for observing living specimens in water. The operation method is basically the same as above.
