Why does the reading lens barrel move from bottom to top when measuring with a reading microscope?

This is to protect the sample and the objective lens, because the focal length of the objective lens is short and close to the sample. If you adjust from far to near, you may accidentally press the objective lens onto the sample.

Because the drum and the objective lens are geared, if they rotate in the opposite direction, there may be a gear meshing gap, the drum value changes, and the phenomenon that the fork wire is not moving in the field of view will affect the accuracy of the data. From inside to outside, from outside to inside, most of them start reading from 0-8.

Extended data

Common operating faults of microscope and

1. Self-sliding of lens barrel

Hold two coarse adjustment handwheels with both hands and tighten them relatively hard. See if the problem can be solved. If it can't be solved, unscrew a coarse adjustment handwheel with a special double column plate handle and add a friction plate. After the handwheel is tightened, if it is difficult to rotate, it means that the added friction plate is too thick, and a thin one can be replaced.

2. Shutter positioning failure

This may be caused by the loosening of the shutter fixing screw and the separation of the positioning pin from the positioning hole. Just put the marbles back into the locating holes and tighten the fixing screws. If the shutter is difficult to rotate after tightening, a washer should be added between the shutter and the stage. The thickness of the washer is that after the screw is tightened, the louver is easy to rotate, the positioning marble does not come out, and the louver is positioned correctly.