How to use high and low magnification lenses of metallographic microscopes
The use of metallographic microscopes can be divided into low-magnification lenses and high-magnification lenses. The functions of the two microscopes are different, so the methods used are also different. The staff of Shanghai Ranchao Optoelectronics Technology Co., Ltd. who specializes in microscopes will introduce it to you. How to use high and low magnification lenses of metallographic microscope:
1. Use of low power lenses
(1) Inspection: Hold the mirror arm with your right hand, take out the microscope from the mirror box, hold the mirror base with your left hand, and place it gently on the experimental table. First check whether any parts of the microscope are damaged. If any damage or poor performance is found, report it immediately.
(2) Preparation: Place the microscope slightly to the left in front, and tilt the lens barrel for observation if necessary. Turn the coarse adjustment knob to slightly raise the lens barrel (or lower the stage) to slightly increase the distance between the objective lens and the stage. Then rotate the objective lens converter and align the low-magnification lens with the light hole in the center of the stage (a "click" sound can be heard).
(3) Aiming the light: Open the aperture, raise the condenser, open both eyes at the same time, look into the eyepiece with the left eye, and adjust the direction of the reflector until the light in the field of view is bright and uniform. The flat mirror of the reflector can easily bring other scenery into the field of vision, and a concave mirror is generally used to focus the light.
(4) Place the specimen piece: With the cover sheet of the specimen piece facing up, place the specimen piece in front of the stage, then push it under the objective lens, and press it with the pressing clamp. If there is a specimen mover, use the spring clip on it. Hold the specimen, and then move the part to be observed to the center of the light hole for observation.
(5) Adjust the focal length: Look at the objective lens from the side of the microscope, and at the same time rotate the coarse adjustment knob to slowly lower the lens barrel or raise the stage. When the distance between the low-magnification lens and the glass is about 5mm, use your left eye to observe the field of view through the eyepiece. , slowly turn the coarse adjustment knob with your left hand to slowly raise the lens barrel until the object image appears in the field of view. If the object image is not clear, you can turn the fine adjustment knob to make the object image clearer.
If you still cannot see the object image after following the above steps, it may be caused by the following reasons:
① Turn the adjustment knob too fast and exceed the focus. The focus should be readjusted as described above.
②The objective lens is not aligned. It should be aligned before observing.
③ If the specimen is not placed in the field of view, the specimen piece should be moved to find the observation object.
④The light is too strong, especially when observing relatively transparent specimens or unstained specimens, this phenomenon is likely to occur. The light should be dimmed before observation.
2. Use of high magnification lenses of metallographic microscopes
(1) Follow the above steps and first use a low power lens to find a clear object image.
(2) Move the part to be observed to the center of the field of view.
(3) Look at the objective lens from the side, move the converter by hand, and change to a high-power lens.
(4) Look into the eyepiece and turn the fine adjustment knob slightly up and down until you see a clear object image in the field of view.
If you still cannot see the object image after following the above operations, it may be caused by the following reasons:
① If the observed part is not within the field of view, it should be found under a low-power lens, then moved to the center of the field of view, and then observed with a high-power lens.
② If the specimen piece is placed upside down, you should put it in the right direction and then follow the above steps.
③The focal length is not adjusted properly. The focal length should be adjusted carefully.
Some microscopes do not match the high-power lens with the low-power lens. When switching from the low-power lens to the high-power lens, the specimen is often unable to turn or is damaged. If this happens, you can slightly raise the lens barrel (or lower the stage). ), adjust the focus directly with a high-power lens. The method of use is: look at the objective lens from the side, adjust the coarse adjustment knob to bring the high-power lens down to the shortest distance from the specimen, then observe the field of view of the eyepiece, slowly adjust the fine adjustment knob, and make the lens rise slowly until the object image is clear. If you need to replace the specimen piece, you should first raise the lens tube (or lower the stage), then move the specimen piece to the front of the stage, and then remove it.
