How to use the microscope concentrator
①, the reason for the use of concentrator
When the magnification increases, on the one hand, because the higher the magnification, the higher the number of lenses, the more light is absorbed by the lens; on the other hand, because the field of view (refers to the scope of the specimen can be seen) of the brightness of the magnification and the magnification of the square is inversely proportional to the magnification of the magnification, that is, the higher the magnification, the darker the field of view. In order to get enough brightness, must be installed with a concentrator, to focus the light on the specimen to be observed.
②, the height at which the concentrator should be located during observation
Observation, to ensure that the * good observation results, the focus of the spotlight concentrator should fall exactly on the specimen. To achieve this condition, it is necessary to adjust the height of the concentrator. When illuminated by parallel light, the focus of the concentrator is about 1.25 mm above the centre of its upper lens plane, so it is often required to raise the concentrator to a height where its upper lens plane is only slightly below the plane of the carrier table, so that the focus of the concentrator may fall on the specimen located on a standard-thickness slide. When using thinner than the standard thickness of the slide to bear the specimen, the position of the concentrator to correspondingly lower some, and when using too thick slides, the focus of the spotlight can only fall below the specimen, not conducive to fine observation.
③, with the objective lens with the concentrator
Here the so-called cooperation, is to make the concentrator and objective lens of the two values of the aperture to obtain the same, in order to better carry out more detailed observation. If the numerical aperture of the concentrator is lower than that of the objective lens, then part of the numerical aperture of the objective lens will be wasted, thus failing to achieve its * high resolution. If the numerical aperture of the concentrator is greater than the numerical aperture of the objective lens, on the one hand, can not improve the resolution of the provisions of the objective lens, on the other hand, the reverse will be due to the illumination beam is too wide, so that the clarity of the object image is reduced. Concentrator and objective lens with the operation method is: in the completion of the illumination, focusing operation, remove the eyepiece directly to the lens barrel, the concentrator under the variable diaphragm closed to the minimum, and then slowly open large. Open it until its aperture is exactly as large as the diameter of the field of view seen, and then press on the eyepiece to observe. Each time the objective lens is switched, it is necessary to carry out this matching operation in turn. Some condenser variable diaphragms have a scale engraved on the rim indicating the opening aperture, which can be fitted according to the scale.
