Operating Procedures and Maintenance of Optical Microscopes
① Placement: Grasp the microscope arm with your right hand and support the base with your left hand to keep the microscope upright. Place it on a clean, stable desktop in a well-lit area near a window. For monocular microscopes, position it on the left side, 3–4 cm away from the table edge.
② Cleaning and Inspection: Check whether the microscope is defective or dirty. Wipe mechanical components of the microscope body with a clean soft cloth. Clean lenses with lens paper; for adhesive or stubborn contamination, use a small amount of xylene.
③ Light Alignment: Raise the tube to 1–2 cm above the stage, and align the low-power objective with the aperture. Adjust the diaphragm and mirror: use the plane mirror for bright light conditions and the concave mirror for dim light. Rotate the mirror with both hands. If using a microscope with a built-in light source, skip this step and adjust the brightness knob instead.
④ Specimen Mounting: Put the slide on the stage with the coverslip facing upward. Secure the slide with spring clips. Turn the stage moving knob to center the target specimen over the aperture.
⑤ Focusing: First turn the coarse focusing knob to slowly lower the tube, and observe from the side until the objective approaches the slide specimen. Then look through the eyepiece with your left eye, and turn the coarse focusing knob counterclockwise with your left hand to raise the tube until the specimen image becomes visible. Fine-tune with the fine focusing knob for sharpness. Operation Notes: Do not focus directly under high-power objectives. When lowering the tube, watch the clearance between objective and specimen from the side and keep track of the critical working distance. For binocular microscopes, adjust the diopter ring if the observer's two eyes have different vision; the binocular tubes can also slide horizontally to fit the interpupillary distance of the user.
⑥ Observation: When using a monocular microscope, keep both eyes naturally open. Use your left eye to view the specimen and your right eye for recording and drawing. Adjust focus and move the specimen field of view with your left hand while recording or sketching with your right hand. During inspection, move the specimen view sequentially to complete full scanning without omission or duplicate observation. Light Intensity Adjustment: Generally, stained specimens require strong light; unstained/colorless specimens require weak light. Low-power observation uses dim light, while high-power observation uses bright light. Besides adjusting the mirror or lamp, adjusting the iris diaphragm is also critical.
