How to adjust the microscope to make the specimen picture clearer
Microscopes have been widely used in modern science.
Microscope types are divided into light microscopes and electron microscopes according to broad categories.
Optical microscopes can be divided into transmission type and reflection type according to the difference in light path form;
Electron microscopes can be divided into transmission type and electron scanning type. The difference from optical microscopes is that the resolution is greatly enhanced, but generally requires the sample to be placed in a vacuum chamber, which is not suitable for some samples.
Here, a common reflection optical microscope is used as an example to illustrate the imaging adjustment method. The principle of the transmission type is the same.
Optical microscopes mainly image through an objective lens group and an eyepiece group. The objective lenses and eyepieces are usually equipped with lens groups of different magnifications. Through combination, a very wide magnification range can be formed. This configuration is because although the high-magnification lens group displays details clearly, the field of view and depth of field are narrow, making it difficult to move between different target areas. Although the low-power lens group has a small magnification, its field of view and depth of field are larger, making it easier to search for targets in a wide range. In addition, some specific samples do not require high magnification, but require all targets in the field of view to be as clear as possible, so low-power lens groups also have their place. The two work together to achieve perfectly clear imaging.
1. Required materials and tools:
Objective lens group: such as 100x, 200x, 300x, 600x, etc.
Eyepiece set: such as 5x, 10x, 15x, 20x, etc.
Focus handwheel: including coarse adjustment and fine adjustment
Stage: can move in any direction within a plane to facilitate finding the target area
sample
light source
color filter
2. Step method:
Turn on the light source
Rotate the coarse adjustment handwheel to move the objective lens assembly and stage to a safe distance.
Based on experience, replace with a low-magnification objective lens set and a suitable eyepiece set
Place the sample that has undergone necessary processing on the stage
Adjust the interpupillary distance of the eyepiece
Move the sample through the stage, search for the sample and target area, observe and select the target through the coarse adjustment handwheel
Replace the appropriate high-magnification objective lens and eyepiece, and focus carefully through the fine adjustment handwheel.
Once you have a clear image, you can start your research and take photos if necessary.
After completing the work, turn off the light source and remove the sample. The objective lens group and eyepiece group usually must also be removed and stored in a dedicated dry and cool place, such as a dry bottle.
Precautions:
Focusing skills: When fine-tuning the focus, there must be a process of blurring-clearing-blurring again. The purpose is to confirm the most accurate focus point found, so it needs to be slightly overshot and then return to a clear focus position.
For certain samples with specific shapes, color filters can be selected to improve detail clarity. For example, for substances that are sensitive to narrow wavelengths and fluorescently dyed samples, color filters of specific colors can be inserted into the light path. In addition, in order to observe the special structure in the metal sample, you can insert a polarizer, adjust the angle, and study the structure condition by observing the specific polarized light reflected by it.
