The construction of a microscope and its use
Microscope is an optical instrument consisting of a lens or a combination of several lenses. It is a symbol of mankind's entry into the atomic age. Instruments used to magnify tiny objects become visible to the human eye. Microscope is divided into optical microscope and electron microscope. Optical microscope is in 1590 by the Dutch Janssen father and son of the first. Nowadays, optical microscopes can magnify objects 1500 times, and the minimum limit of resolution is 0.2 microns.
There are many types of optical microscopes, in addition to the general, there are: ① dark-field microscope, a dark-field spotting mirror, so that the illumination of the beam does not come from the central part of the specimen, but from the four sides of the microscope to the specimen. ② fluorescence microscope, ultraviolet light as a light source, so that the irradiated object emits fluorescence microscope. The electron microscope was first assembled in 1931 in Berlin, Germany by Knorr and Haroska. This microscope uses a high-speed electron beam instead of a light beam. Because the wavelength of the electron stream is much shorter than that of light waves, the magnification of the electron microscope can reach 800,000 times, and the minimum limit of resolution reaches 0.2 nm. The scanning electron microscope, which began to be used in 1963, can enable people to see the tiny structures on the surface of objects.
■ Main Uses
Microscopes are used to magnify the image of tiny objects. Generally used in biology, medicine, microscopic particles and other observations.
Structure of an optical microscope
The structure of an ordinary optical microscope is mainly divided into three parts: mechanical part, illumination part and optical part.
Mechanical part
(1) Mirror base: It is the base of the microscope, which is used to support the whole mirror body.
(2) Mirror column: It is the upright part above the mirror base, which is used to connect the mirror base and the mirror arm.
(3) Mirror arm: one end is connected to the mirror column and the other end is connected to the mirror tube, which is the part of the hand grip when taking and placing the microscope.
(4) Mirror tube: attached to the upper front of the mirror arm, the upper end of the mirror tube is equipped with an eyepiece, the lower end of the mirror tube is equipped with an objective lens converter.
(5) Objective converter (rotator): connected to the bottom of the prism shell, can be freely rotated, there are 3-4 holes on the disc, is the installation of the objective part, turn the converter, you can switch to different multiples of the objective lens, when you hear the sound of touching the knocking sound, before you can observe, at this time the optical axis of the objective lens is exactly aligned with the centre of the through-hole, the optical path is connected.
(6) mirror stage (carrier stage): below the barrel, the shape of a square, round two kinds, to place the slide specimen, the centre of the light hole, the microscope we use is equipped with a slide specimen propeller (pusher), the propeller on the left side of the spring clip, used to clamp the slide specimen, the mirror stage under the propeller adjustable wheels, the slide specimen can be moved for the left and right, forward and backward direction.
(7) Adjuster: It is a spiral of two sizes mounted on the mirror column, which moves the mirror table up and down when it is adjusted.
(1) Coarse regulator (coarse spiral): large spiral called coarse regulator, moving the mirror stage for rapid and large-scale lifting, so it can quickly adjust the distance between the objective lens and the specimen to make the object presented in the field of view, usually in the use of low magnification, the first use of coarse regulator to quickly find the object.
② fine adjuster (fine spiral): a small spiral called fine adjuster, moving the mirror stage can be slowly raised and lowered, mostly used in the use of high magnification, so as to get a clearer image, and to observe the different levels of the specimen and the different depths of the structure.
