What are the structures of the mechanical parts of an optical microscope
The mechanical part of the microscope includes the lens holder, the lens barrel, the nosepiece, the stage, the pusher, the coarse adjustment handwheel, the fine adjustment handwheel and other components.
1) Mirror base: The mirror base is the basic bracket of the microscope, which consists of two parts: the base and the mirror arm. Attached to it is the stage and the lens barrel, and it is the basis for mounting the optical magnification system components. The base and mirror arms stabilize and support the entire microscope.
2) Lens barrel: The eyepiece is connected to the top of the lens barrel, and the converter is connected to the bottom to form a dark room between the eyepiece and the objective lens (installed under the converter). The distance from the trailing 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 relative to a certain length of the lens barrel. The change in the length of the lens barrel not only changes the magnification, but also affects the image quality. Therefore, when using a microscope, the length of the lens barrel cannot be changed arbitrarily. Internationally, the standard barrel length of the microscope is set at 160mm, and this number is usually marked on the shell of the objective lens. There are two types of lens barrels: monocular and binocular.
3) Nose changer: Three to four objective lenses can be installed on the nosepiece, generally three objective lenses (low magnification, high magnification and oil lens). Rotate the converter to align one of the objective lenses with the lens barrel as required (note that it is to rotate the conversion lens, not to hold the objective lens for rotation) to form a magnifying system with the eyepiece.
4) Stage: There is a hole in the center of the stage, which is the light channel. There are spring specimen clamps and pushers on the stage, which are used to fix and move the position of the specimen, so that the object to be examined is just in the center of the field of view.
5) Pusher: It is a mechanical device for moving the specimen. It is composed of a metal frame with two propelling gear shafts, one horizontal and one vertical. A good microscope has a scale scale engraved on the vertical and horizontal frame rods, which constitutes a very precise plane coordinate. Tie. If we need to observe a certain part repeatedly, we can write down the value of the vertical and horizontal scales, and move to the same value to find it later.
6) Coarse adjustment handwheel (coarse screw): The coarse adjustment handwheel is a mechanism for quickly adjusting the distance between the objective lens and the specimen.
7) Fine-tuning handwheel (fine spiral): The focus can only be adjusted roughly with the coarse handwheel. To get the clearest object image, it is necessary to use the macro spiral for fine-tuning.
