How to adjust the microscope so that the image of the specimen is clearer
Microscopes have been widely used in modern science.
The types of microscopes are divided into optical microscopes and electron microscopes according to broad categories.
Optical microscopes can be divided into transmission and reflection according to the difference in the form of optical path;
Electron microscope can be divided into transmission type and electron scanning type, and the difference between optical microscope is that the separate rate is greatly enhanced, but the general requirements of the sample placed in a vacuum chamber, some samples are not suitable.
Here to common reflective optical microscope as an example to illustrate the adjustment of the imaging method, the same principle of transmission type.
Optical microscope mainly through the objective lens group and eyepieces into the image, objective lens and eyepieces are usually equipped with different magnification of the mirror group. Through the combination can form a span of very large magnification range, this configuration is because the high-magnification lens group although the details show clear, but the field of view and depth of field is narrow, not easy to move in different target areas. The low magnification group has a small magnification, but the field of view and depth of field are larger, making it easier to search for targets over a wide area. In addition, some specific samples do not require a large magnification, but require all targets in the field of view as clear as possible, so the low magnification lens group is also useful. Both can be used to obtain perfect clear imaging.
I. Required materials and tools:
Objective lens group: such as 100x, 200x, 300x, 600x, etc.
Eyepiece set: such as 5x, 10x, 15x, 20x, etc.
Focusing handwheel: including coarse and fine adjustment
Carrier table: can be moved in any direction within a plane, easy to find the target area
Sample
Light source
Color filter
Second, step by step method:
Turn on the light source
Rotate the coarse adjustment handwheel, pull the objective lens group and the carrier table to a safe distance
Replace the low magnification objective lens set and the appropriate eyepiece set according to experience
Place the sample after necessary treatment on the carrier stage
Adjust the pupil distance of the eyepiece
Move the sample through the stage, search for the sample and target area, observe and select the target with the coarse adjustment handwheel
Replace the objective and eyepieces with the appropriate high magnification lenses and focus carefully with the fine adjustment handwheel.
Obtain a clear image for study and take photographs if necessary.
After completing the work, turn off the light source, remove the sample, the objective lens set and eyepiece set usually must also be removed and placed in a special dry, cool place for storage, such as dry bottle.
II. Precautions:
Tips for focusing: when fine-tuning the focus, there shall be a process of blurring-clearing-re-blurring, the purpose is to confirm the most accurate focusing point found, so it is necessary to go over the head a little, and then turn back to the clear focusing position.
For some specific shapes of samples, color filters can be selected to improve the clarity of details. For example, for substances that are sensitive to narrow wavelengths and samples that have been fluorescently dyed, a filter of a specific color can be inserted into the optical path. Also, in order to observe special tissues in metal samples, a polarizer can be inserted, the angle adjusted, and the condition of the tissue studied by observing the specific polarized light reflected from it.
