Adjustment of Microscope Illumination Optical System
In order to ensure that the field of view of the microscope can be evenly and fully illuminated, the illumination optical system must be adjusted when the microscope is first installed and debugged. requirements. In addition, correctly mastering the adjustment of the illumination optical path system is a necessary step after replacing the light source bulb during the use of the microscope, and it is also a necessary means to check the performance of the microscope from time to time during daily use. The adjustment of the microscope illumination optical path system mainly includes the following four items:
(1) Preliminary adjustment of the lighting source lamp house in the microscope
① First open the shell of the lamp chamber, press the spring clip to install the halogen bulb into the socket, and avoid direct contact with the bulb with your fingers during installation (you can use soft cloth or paper to separate it), so as not to leave fingerprints and other dirt on the bulb, which will affect the bulb. service life.
② Put the lamp house on the table, after turning on the power, use a special screwdriver to adjust the focus knob hole of the lamp (marked with "←→"), so that the filament is projected on the wall 1-2m away, and the filament image is adjusted. Then adjust the height of the lamp and adjust the thread hole (marked with "──") to make the position of the filament appropriate; then adjust the left and right position of the lamp to adjust the screw hole (marked with "──") to make the left and right position of the filament appropriate .
(2) The purpose of the inspection and correction of the position of the light source illuminant (filament) in the microscope is to adjust the image end of the illuminant correctly into the field of view of the objective lens, and to ensure that the field of view of the microscope is fully protected from the perspective of the light source. And uniform lighting, which is a prerequisite for adjusting the Kuhler lighting system. Basic tools needed: The centering telescope is equipped when the microscope is purchased.
① Unplug the frosted glass sleeve in the lamp house, and put the lamp house back on the microscope;
② Select the 10× objective lens, turn on the light source program to find the sample and focus it clearly, and then switch to the 40× objective lens to focus the sample clearly (the 40× objective lens can see the whole picture of the filament);
③ Open the aperture diaphragm and field diaphragm of the condenser to the maximum;
④ Unplug one of the eyepieces, replace with a centering telescope, grab the white part, stretch the black eyepiece with the other hand, and you can see the filament image in the field of vision;
⑤ If the position of the filament is not suitable, adjust the "──" hole to adjust the filament image in the horizontal direction, and adjust the "──" hole to adjust the filament image in the vertical direction until the filament image is adjusted to just fill the aperture of the objective lens round image of light;
⑥ After the adjustment is completed, insert the frosted glass sleeve back to its original position, unplug the centering telescope, and replace the eyepiece for the next adjustment. The above-mentioned adjustment of the illumination light source lamp chamber outside the microscope and the verification of the position of the light source luminous body inside the microscope only need to be carried out when the microscope is first installed and debugged and when the bulb is replaced, and the microscope cannot be adjusted randomly when using the microscope. In case of confusion, it can be adjusted back to the original state according to the above steps.
(3) Correct adjustment of the Kohler illumination system One of the main tasks of the correct adjustment of the microscope is the adjustment of the illumination optical path system, and the key is the adjustment of the Kohler illumination system. For every person who uses a microscope, especially those who do photomicrographs, they should have a certain understanding and mastery of the principle of the Kuhler illumination system and its adjustment steps in order to give full play to the functions of the microscope and take pictures. The photos that come out can be more consistent and perfect in effect. The principle of the Kohler illumination system is simply: the light emitted by any point on the light source illuminant can illuminate the field of view of the microscope, and the light emitted by each point on the light source illuminant is collected, and in the field of view of the microscope A very full and uniform illumination is achieved. The purpose of adjusting the Kuhler lighting system is to obtain uniform and sufficient illumination for the observed field of view, and to prevent stray light from affecting or interfering with the imaging system, so as to avoid fogging on the film during photography. Necessary components for a high-adjustment Kohler illumination system: field diaphragm, condenser lens system that can be adjusted on-axis.
① Use 10× objective lens and 10× eyepiece;
② Put the lens at the front end of the condenser into the optical path, adjust the aperture diaphragm to a moderate position (not too big or small), then raise the condenser to the top position, and adjust the condenser turntable to the bright field "J" position;
③ Adjust the field diaphragm to the minimum (0.1);
④ Put the sealed biological sample on the stage, turn on the light source, and focus clearly;
⑤ There will be a partially illuminated area or bright spot in the field of view, which is the blurred image of the field diaphragm, in which the details of the sample can be clearly seen; outside it is a darker field of view, which may not necessarily See the details of the sample clearly;
⑥ Slightly adjust the condenser downwards, so that the bright spot in the field of view gradually shrinks and gradually becomes a clear polygonal image, which is the clear image of the field diaphragm;
⑦ In general, the polygonal image is not in the center of the field of view, and it is necessary to adjust a pair of centering screws of the condenser to adjust the polygonal image of the field diaphragm to the central position;
⑧ Open the diaphragm of the field of view gradually, so that the polygon image becomes the inscribed polygon of the field of view, and further check the alignment status. If the alignment is not ideal, continue to fine-tune the alignment screw;
⑨ Open the diaphragm of the field of view slightly wider, so that its polygonal image just disappears on the edge of the field of view. At this point, the adjustment of the Kohler illumination system is completed. After the Kohler lighting system is adjusted, the entire field of view is evenly illuminated, and the micrographs taken are bright and clear with normal contrast. In the future use, special attention should be paid to: a. The field diaphragm cannot be opened arbitrarily, but the field diaphragm can be narrowed with the increase of the multiple of the objective lens, and can be enlarged with the decrease of the multiple of the objective lens; b. Condenser The high and low positions of the condenser are not allowed to be adjusted randomly, otherwise it will destroy the adjusted Kohler illumination system; c. When using an objective lens below 10×, the front lens of the condenser should be placed out of the optical path, and when using an objective lens of 10× or above, the front end lens should be placed The lens is placed into the optical path; d. Regarding the problem of matching the multiple of the objective lens with the size of the field diaphragm, in actual use, it is not necessary to close or open the field diaphragm as a general observation, but when doing microphotography, in order to To avoid the interference of stray light on the camera system, in order to take more perfect photos, the field diaphragm should be adjusted to just disappear on the edge of the observed field of view when using an objective lens of each multiple. More complicated work, but it must be done. The simpler method is to adjust the field diaphragm corresponding to each multiple objective lens in advance, and mark it, and then directly adjust it to the corresponding position according to the mark when using it later.
