Mechanical part structure of optical microscope
The mechanical part of microscope includes lens holder, lens barrel, objective lens converter, stage, pusher, coarse adjustment handwheel, fine adjustment handwheel and other parts.
1) Mirror base: The mirror base is the basic support of the microscope, which consists of two parts: the base and the mirror arm. It is connected with the objective table and the lens barrel, which is the basis for installing the components of the optical amplification system. The base and the mirror arm play the role of stabilizing and supporting the whole microscope.
2) Lens barrel: the lens barrel is connected with the eyepiece and the converter, forming a darkroom between the eyepiece and the objective lens (installed under the converter). The distance from the rear edge of the objective lens to the rear end of the lens barrel is called the mechanical barrel length. Because the magnification of the objective lens is for a certain lens barrel length. With the change of lens barrel length, not only the magnification changes, but also the imaging quality is affected. Therefore, when using a microscope, the length of the lens barrel cannot be changed arbitrarily. Internationally, the standard tube length of a microscope is set at 160mm, which is usually marked on the shell of the objective lens. There are two kinds of lens barrels: single barrel and double barrel. The single barrel is divided into upright and inclined, while the double barrel is inclined.
3) objective lens converter: three to four objective lenses can be installed on the objective lens converter, usually three objective lenses (low power, high power and oil mirror). Rotate the converter to align one of the objective lenses with the lens barrel as required (note that the lens can be changed by rotating the converter, and the lens can't be rotated by holding the objective lens), and form an amplification system with the objective lens.
4) Stage: There is a hole in the center of the stage for light passage. A spring specimen holder and a pusher are installed on the stage, which are used to fix and move the position of the specimen, so that the object under microscope is located in the center of the visual field.
5) Pusher: It is a mechanical device for moving specimens. It is made of a metal frame with two vertical and horizontal pushing toothed shafts. A good microscope is engraved with scale scales on the vertical and horizontal frames to form a very precise plane coordinate system. If we need to observe a certain part repeatedly, we can write down the values of the vertical and horizontal rulers and move to the same values later.
6) Coarse adjustment handwheel (coarse screw): The coarse adjustment handwheel is a machine that moves quickly to adjust the distance between the objective lens and the specimen.
7) Fine-tuning handwheel (fine screw): Only the focal length can be roughly adjusted by coarse-tuning handwheel. To get the clearest image, fine-tuning is required by using macro screw.
