Several special types of optical microscopes and their differences
Dark-field microscopes do not have the function of observing the fine structure inside an object, but they can distinguish the existence and movement of particles of 0.004μm or more. Therefore, it is often used to observe the structure of living cells and the movement of particles inside cells.
The basic principle of the dark-field microscope is the Tyndall effect. When a beam of light passes through a dark room, from the direction perpendicular to the incident light, a bright dust "pathway" can be observed in the air, a phenomenon known as the Tyndall effect.
Dark-field microscope in the ordinary optical microscope on the replacement of the dark-field condenser, due to the condenser inside the parabolic structure of the block, the light irradiated on the surface of the object to be examined can not directly enter the objective lens and eyepiece, only the scattered light can be passed, and thus the field of view is dark.
The basic use of dark-field microscope is as follows:
1. Install the dark-field concentrator (or use a thick piece of black paper to make a light shield, placed under the ordinary microscope's concentrator, you can also get the dark-field effect).
2. Choose a strong light source, usually illuminated by a microscope lamp, to prevent direct light from entering the objective lens.
3. Add a drop of cedar oil between the condenser and the slide to avoid total reflection of the illumination light on the condenser, which will not reach the object to be examined and will not get the dark field illumination.
4. Make centre adjustment, i.e. move the condenser horizontally so that the optical axis of the condenser and the optical axis of the microscope are strictly in a straight line. Lift the concentrator, the focus of the concentrator (Figure 1-2 in the apex of the cone beam) aligned with the object to be examined.
5. Select the objective lens corresponding to the concentrator, adjust the focus, according to the method of ordinary microscope operation.
Stereomicroscope
Stereo microscope, also known as solid microscope or anatomical microscope, its imaging for the orthogonal three-dimensional space image, and has a strong sense of three-dimensionality, imaging clear and broad, long working distance (usually 110mm), as well as continuous magnification of viewing and other characteristics.
