What is the optical principle used in metallographic microscopes?
Metallographic microscope is used to identify and analyze the internal structure of various metals and alloys. It is an important instrument for studying metallography and a key equipment for the industrial sector to identify product quality. It is mainly used to identify and analyze various metals and alloys. organizational structure. The optical principles used in metallographic microscopes are mainly divided into bright field and dark field.
The main characteristics of bright field are based on the color and transmittance of the specimen. The specimen usually needs to be dyed to facilitate observation. Of course, narrowing the aperture or upper and lower condensers can also be used. Brightfield is the basis for other optical microscopes.
Dark field is a method designed based on the Tyndall effect principle to observe detection objects under dark background conditions. Under normal conditions, people cannot see indoor dust. This is because dust particles are exposed to strong direct light and diffraction. interference. But if you let the light pass through the window in dark indoor conditions, it will be easy to see. This is because when the light is reflected or diffracted, the dust particles seem to increase in size. Dark field is a lens that uses a special method to prevent direct light from entering the objective lens. Instead, the direct light first passes through the dark field condenser and then changes its path so that it enters the object being measured obliquely. The surface reflects or diffracts the light into the objective lens to form a print on the object. Bright image on dark background.
Instructions for using metallographic microscope:
1) First, plug the light source plug of the microscope into the transformer and connect the power supply through the low-voltage (6~8v) transformer.
2) Select the required objective lens and eyepiece according to the magnification, install them on the objective lens holder and in the eyepiece tube respectively, and turn the converter to the fixed position.
3) Place the sample in the center of the sample stage, place the observation surface downward and press it with a spring leaf.
4) Turn the coarse adjustment handwheel to lower the stage first, and observe with your eyes at the same time, so that the objective lens is as close to the specimen surface as possible (but do not touch it), then turn the coarse adjustment handwheel in the opposite direction to gradually raise the stage. To adjust the focus, when the brightness of the field of view increases, use the fine-tuning handwheel to adjust until the object image becomes clear.
5) Appropriately adjust the aperture diaphragm and field diaphragm to obtain the best quality object image.
