Experimental summary of the structure and use of microscopes
An ordinary optical microscope consists of a mechanical part, an illumination part and an optical part. The mechanical part of the microscope includes the lens base, lens barrel, objective converter, stage, pusher, coarse adjustment handwheel, fine adjustment handwheel and other components.
The mirror base is the basic support of the microscope, which consists of two parts: the base and the mirror arm. There is a stage and lens tube attached to it, which is the basis for installing the components of the optical magnification system. The base and mirror arms stabilize and support the entire microscope. The eyepiece is connected to the upper part of the lens barrel and the converter is connected to the lower part, forming a darkroom between the eyepiece and the objective lens (installed under the converter).
Three to four objective lenses can be installed on the nosepiece, usually three objective lenses (low magnification, high magnification and oil lens). By turning the converter, you can align one of the objective lenses with the lens barrel as needed (note that you are rotating the converter to change the lens, you cannot hold the objective lens to rotate), and form a magnifying system with the eyepiece.
There is a hole in the center of the stage for light passage. There are spring specimen clamps and pushers installed on the stage, which are used to fix and move the position of the specimen so that the microscope object is exactly in the center of the field of view. The pusher is a mechanical device for moving specimens. It is composed of a metal frame with two pusher pinions, one horizontally and one vertically.
What does 10/0.25 mean on the objective lens of a microscope?
10 is the magnification of the objective lens, and 0.25 is the numerical aperture of the objective lens. \x0d\x0a The numerical aperture (N.A=n.sinu) of the objective lens is the main parameter that determines the microscope's discrimination rate (1/d). The larger the value, the higher the discrimination rate - that is, the higher the ability to resolve fine targets. Therefore, the discrimination rate of a microscope is directly proportional to the numerical aperture of the objective lens and inversely proportional to the wavelength of the illuminating light. \x0d\x0a It should be pointed out that the discrimination rate of a microscope is not the same thing as the magnification. Just as the target is magnified, it does not necessarily look clear; only when the objective lens has a high discrimination rate, can the details of the target be clearly distinguished. \x0d\x0a The vertical discrimination rate of a microscope is also called the depth of field; this will be familiar to anyone who has used a camera. \x0d\x0a The identification rate of a microscope is only related to the objective lens and has nothing to do with the eyepiece; the eyepiece only plays a magnifying role. Therefore, the objective lens is an important part of the microscope.
