What are the optical parts of a microscope
(1) Eyepiece
It usually consists of two sets of lenses, the upper set is also called the "eyepiece" and the lower one is called the "field lens". A field diaphragm (metal ring device) is installed between the two or below the field lens, and the intermediate image enlarged by the objective lens falls on the plane of the field diaphragm, so an eyepiece micrometer can be added on it. The magnification is engraved on the top of the eyepiece, such as 10×, 20×, etc. According to the size of the field of view, eyepieces can be divided into ordinary eyepieces and wide-angle eyepieces. Some microscope eyepieces are also equipped with a diopter adjustment mechanism, and the operator can adjust the diopter for the left and right eyes respectively. Another camera eyepiece (NFK) can be used for shooting.
(2) Objective lens
It consists of an array of lenses and is installed on the converter, also known as the objective lens. Usually each microscope is equipped with a set of objective lenses with different magnifications, including:
①Low magnification objective lens: refers to 1×～6×;
②Medium magnification objective lens: refers to 6×～25×;
③High magnification objective lens: refers to 25×～63×;
④Oil immersion objective lens: refers to 90×～100×.
Among them, when the oil immersion objective lens is used, it needs to fill the liquid with a refractive index of about 1.5 (such as cedar oil, etc.) between the lower surface of the objective lens and the upper surface of the cover glass, which can significantly improve the resolution of microscopic observation. Other objectives were used directly. During the observation process, the selection of objective lenses generally follows the order from low to high, because the field of view of the low-power lens is large, and it is easy to find the specific part to be inspected. The magnification of a microscope can be roughly regarded as the product of the magnification of the eyepiece and the magnification of the objective lens.
(3) Concentrator
Consisting of a condenser lens and an iridescent aperture, it is located under the stage. The function of the condenser lens is to focus the light within the field of view; the iridescent aperture under the lens group can be enlarged or reduced to control the light transmission range of the condenser, adjust the light intensity, and affect the imaging resolution and contrast. When using, it should be adjusted according to the purpose of observation and the intensity of the light source to obtain the best imaging effect.
(4) Light source
The earlier ordinary optical microscope used the reflector on the mirror base to reflect natural light or light to the center of the condenser lens as a light source for mirror inspection. Reflectors are composed of a mirror with a flat surface and another concave surface. Use a concave mirror when no concentrator is used or when the light is strong, and the concave mirror can play the role of converging light; when a concentrator is used or the light is weak, a plane mirror is generally used. The newly produced microscopes generally install the light source directly on the mirror base, and have a current adjustment screw for adjusting the light intensity. The light source types include halogen lamps, tungsten lamps, mercury lamps, fluorescent lamps, metal halide lamps, etc.
