The two parts of the microscope
(1) The mechanical part of the microscope
1. Lens barrel
It is a long circular hollow tube on the upper part of the microscope. The eyepiece is installed on the upper end of the tube mouth, and the lower end is connected with the objective lens converter. The function is to protect the optical path and brightness of imaging.
2. Converter
It is fixed at the lower end of the lens barrel and is divided into two layers, the upper layer is fixed and the lower layer can rotate freely. There are 2 to 4 round holes on the converter, which are used to install low-magnification or high-magnification objective lenses of different magnifications.
3. Coarse focus helix
Located above the lens arm, it can be turned so that the lens barrel can move up and down to adjust the focal length.
4. Fine focus spiral
Located at the bottom of the mirror arm, its movement range is smaller than that of the coarse quasi-focus screw, and the focus can be fine-tuned.
5. Mirror holder
It is a horseshoe-shaped metal base located under the mirror arm and at the bottom of the microscope. Used to stabilize and support the mirror body.
6. Mirror column
A short column standing upward from the mirror base. The upper is connected to the mirror arm, and the lower is connected to the mirror base, which can support the mirror arm and the stage.
7. Tilt joints
There is a movable joint at the junction of the mirror column and the mirror arm. It can make the microscope tilt back within a certain range (generally the tilt should not exceed 45°) for easy observation. However, when using temporary mounts for observation, it is forbidden to use tilted joints, especially when the mounts contain acidic reagents, so as not to deface the mirror body.
8. Stage
A metal platform protruding forward from the mirror arm. It is square or round and is the place to place slide specimens. There is a light hole in the center, and there is an elastic metal clip on the left and right of the light hole, which is used to hold down the glass slide. More sophisticated microscopes often have propellers on the stage, which include clips and propellers, which can move the slices on the stage in addition to clamping the slices. How to Identify a Microscope
(2) Optical part of the microscope
1. Eyepiece
It is the lens mounted on the upper end of the lens barrel. It is composed of a group of lenses, which can make the objective lens multiply to resolve and magnify the object image, such as 5×, 10×, 15×, 20×.
2. Objective lens
It is a key component that determines the quality of the microscope. Installed on the hole of the converter, it is also composed of a set of lenses, which can clearly magnify the object. Generally, there are three objective lenses with different magnifications, namely: low magnification objective lens (8× or 10×), high magnification objective lens (40× or 45×) and oil immersion objective lens (90× or 100×), you can choose one to use according to your needs. The magnification of a microscope is the multiple of the eyepiece multiplied by the objective.
3. Mirror
Below the concentrator there is a double-sided circular mirror with one side flat and the other concave. It can be flipped in various directions. When the light is strong, use a flat mirror, otherwise use a concave mirror.
4. Concentrator
(Student microscopes generally do not have this device) It is composed of a concave lens, which can concentrate the light projected by the mirror. There is a concentrator adjusting screw in front of the mirror column, which can lift the concentrator up and down to adjust the intensity of the light. When it goes down, the brightness decreases, and when it goes up, the brightness increases.
5. Iridescent aperture
Also known as the iris diaphragm, it is composed of many metal sheets (student microscopes generally do not have this device), and has this device on higher microscopes. When in use, move its handle to control the light transmission range of the condenser lens to adjust the light intensity. A metal ring is often attached under the iridescent aperture, and a filter is installed on it to adjust the hue of the light source.
6. Shutter
A simple microscope has no condenser and iridescent aperture, but a shutter. The shutter is disc-shaped with round holes (apertures) of different sizes on it. The aperture is aligned with the light hole to adjust the intensity of the light. How to Identify a Microscope
Microscope imaging principle (magnification principle)
Light → mirror → shutter → aperture → specimen (must be transparent) → lens of objective lens (magnified into an inverted real image for the first time) → lens tube → eyepiece (magnified into a virtual image again) → eye.
