Microscope Construction and Use
1. Mechanical part:
The mechanical part of the microscope includes mirror base, lens barrel, objective lens converter, stage, pusher, coarse adjustment handwheel, fine adjustment handwheel and other components.
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 stage and the lens barrel, which is the basis for installing the components of the optical magnification system. The base and mirror arm stabilize and support the entire microscope.
2) Lens barrel: The lens barrel is connected to the eyepiece at the top and the converter at the bottom to form a dark room 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. The change of 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 as 160mm, and this number is usually marked on the outer casing of the objective lens. There are two types of lens barrels: monocular and binocular. The monocular is divided into vertical and inclined, while the binoculars are all inclined.
3) Objective lens changer: Three to four objective lenses can be installed on the objective lens changer, generally three objective lenses (low magnification, high magnification and oil lens). Turn the converter, and one of the objective lenses can be aligned with the lens barrel as required (note that the rotation is to change the lens, and the objective lens cannot be rotated), and the eyepiece forms a magnification system.
4) Stage: There is a hole in the center of the stage for light passage. There are spring sample holders and pushers on the stage, which are used to fix and move the position of the sample, so that the object of microscope inspection is just in the center of the field of view.
5) Pusher: It is a mechanical device for moving specimens. It is composed of a metal frame with two push gear shafts, one horizontal and one vertical. A good microscope has a scale engraved on the vertical and horizontal rods to form very precise plane coordinates. Tie. If we need to observe a certain part repeatedly, we can write down the value of the vertical and horizontal scales, and then move to the same value to find it.
6) Coarse adjustment handwheel (coarse spiral): The coarse adjustment handwheel is a device that moves quickly to adjust the distance between the objective lens and the specimen.
7) Fine-tuning handwheel (fine screw): The focus can only be adjusted roughly with the coarse-tuning handwheel. To get the clearest object image, you need to use the macro-pitch screw for fine adjustment.
