Small Details and Precautions for Microscope Operation
Stereomicroscopes are widely used in industry, agriculture and scientific research institutions due to their many advantages. Minor faults occurring during operation can be resolved on-site according to actual conditions. Common faults encountered in practical use include blurry or dirty fields of view. Potential causes are contaminants on the specimen, eyepiece surface, objective lens surface or work plate surface.
The problem can be solved by cleaning the specimen, eyepiece, objective lens and work plate surface as needed. Non-coincident double images may result from incorrect interpupillary distance adjustment; this can be fixed by readjusting the interpupillary distance. Non-coincident double images may also be caused by improper diopter adjustment, in which case the diopters should be reset. Another possible cause is mismatched magnification between the left and right eyepieces. Inspect the eyepieces and reinstall a pair of eyepieces with identical magnification. If the image is indistinct, dirt on the objective lens surface is the likely cause, and the objective lens should be cleaned. If the image turns blurry during zooming, improper diopter setting or focusing may be responsible; readjust the diopters and focus. If the bulb frequently burns out or the light flickers, the local mains voltage may be excessive, or wiring connections may be loose. Carefully check the supply voltage and whether the microscope wiring connections are secure. If these are normal, the bulb may be failing and should be replaced.
Pre-use calibration of a stereomicroscope mainly includes focusing, diopter adjustment, interpupillary distance adjustment and bulb replacement, which are described separately below.
① Focusing: Insert the work plate into the plate mounting hole on the base. Use a frosted glass plate for transparent specimens and a black-and-white plate for opaque specimens. Loosen the locking screw on the focusing slide, and adjust the height of the microscope body to achieve a working distance matching roughly the magnification of the selected objective lens. Tighten the locking screw once set. For focusing adjustment, flat objects such as printed paper, rulers or set squares are recommended.
Diopter adjustment: First turn the diopter rings on both the left and right eyepiece tubes to the zero mark. Normally, observe through the right eyepiece first. Rotate the zoom knob to the lowest magnification position. Turn the focusing knob and diopter ring to focus on the specimen until the image is sharp. Then turn the zoom knob to the highest magnification and adjust again until the image remains clear. Next, observe through the left eyepiece. If the image is blurry, axially adjust the diopter ring on the left eyepiece tube until the specimen image becomes sharp.
