Basic structure and function of optical microscope

- Jul 10, 2017-

An optical microscope is a commonly used instrument in the field of biological and medical research, and it has a very wide range of uses in the teaching and research of cell biology, histology, pathology, microbiology and other related subjects, and is a powerful tool for studying human and other organism tissues and cell structures. A general light microscope is mainly composed of mechanical system and optical system, while optical system mainly includes light source, reflector, concentrator, objective lens and eyepiece.

Basic structure and function of optical microscope

1. Mechanical part

Mirror tube: A cylindrical structure mounted at the top of a microscope or in front of the mirror arm, with an eyepiece at the upper end and a lower end connected to an objective converter.

Objective Lens Converter: Also known as objective lens conversion disk. is a disk-like structure mounted below the mirror tube that rotates freely, either clockwise or counterclockwise. The $number is uniformly distributed with a circular hole, which is used to load the objective lens with different magnification. The rotating animal mirror conversion disk allows different objective lenses to arrive at the working position (i.e., with the optical path).

Mirror arm: A curved structure that supports the lens tube and the mirror, which is the part of the grip held when the microscope is taken. The binocular vertical microscope has a tilted joint between the mirror arm and the mirror column beneath it, which can make the mirror tube tilt back to a certain angle to facilitate observation, but the tilt angle should not be more than 45 degrees when using, otherwise the microscope is apt to overturn due to the center of gravity.

Focusing device: Also known as the focus of the spiral, in order to adjust the focal length of the devices, the coarse-tuned spiral (large spiral) and fine-tuned spiral (small helix) two. The coarse-tuning spiral can make the mirror tube or the load table with a faster speed or a larger take-off and landing, can quickly adjust the focal length so that the object appears in the field of vision, suitable for macro-microscope observation of the focus. And the fine-tuning spiral can only make the mirror tube or the loading platform slow or small amplitude of take-off and landing (rising or descending distance is not easy to be observed by the naked eye), it is applicable to the different levels of focusing or observing specimen of high magnification mirror and oil mirror, and then using fine focusing helix and fine adjusting focal length on the basis of coarse adjusting spiral focusing.

Load table: Also known as Mirror, is located at the bottom of the objective lens converter, the square platform, is placed in the observation of the glass specimen of the place. The center of the platform has a round hole, called the pass-through hole, from the lower light through this hole to the specimen.

Mirror column: A short column connecting the mirror arm with the mirror seat.

Pedestal: A structure located at the bottom of the microscope, for the base of the entire microscope, for supporting and stabilizing the mirror. Some microscopes are fitted with light sources such as lighting in the lens seat.

2, optical system part

The optical system of the microscope mainly includes the objective lens, the eyepiece and the illumination device (the reflector, the concentrator and the aperture, etc.).

Eyepiece: mounted at the upper end of the lens tube, which acts as a further amplification of the object magnified by the objective lens. Each microscope is usually configured with an eyepiece of different magnification $number, common with 5x, 10x and 15x (x for magnification) of the eyepiece, can be selected according to different needs, the most commonly used is the 10x eyepiece.

Objective lens: mounted on the objective lens converter. Each optical lens has a $number objective, each of which is composed of several convex lenses and concave, and is the most important optical component of the microscope, which determines the resolution of the optical mirror. The magnification of common objective lenses is 10x, 40x and 100x. Generally, the objective of 8x or 10x is called a low magnification mirror (which is called a magnifying glass below 5x), a 40x or 45x is called a high-power mirror, and a 90x or 100x is called an oil mirror, which is used in a mirror oil.

Concentrator: The lower part of the light hole in the platform, consisting of condenser and aperture, whose main function is to concentrate light on the specimen to be observed. The condenser is composed of a $number lens, which acts as a convex lens and can be assembled into bundles of light. The aperture, also known as a rainbow aperture or aperture, is located at the lower end of the concentrator and is a variable aperture that controls the size of the light beam into the concentrator. It is arranged by a combination of more than 10 pieces of metal sheet, with a small handle on the outside, which can make the aperture of aperture larger or smaller to adjust the intensity of the light.

Reflector: Located below the condenser, it can rotate in all directions, and can reflect light from different directions into the concentrator. The reflector has two faces, one side is the plane mirror, the other side is concave, concave has the concentrating function, is suitable for the weak light and scatters the light to use, the light is strong when chooses the mirror (now some new optical microscope all has the own light source, but has not the reflector;