How to use the optical microscope correctly

Several points for attention when using the optical microscope correctly: 1. The problem of correct installation Before using the microscope, first install the eyepiece and objective lens of the microscope. The installation of the eyepiece is relatively simple. The main problem lies in the installation of the objective lens. Since the objective lens is more expensive, if the thread is not closed when the student installs it, it is easy to fall to the ground and cause the lens to be damaged. Therefore, to be on the safe side, use the lens of the optical microscope correctly. Points to note: 1. The problem of correct installation Before using the microscope, first install the eyepiece and objective lens of the microscope. The installation of the eyepiece is relatively simple. The main problem lies in the installation of the objective lens. Since the objective lens is more expensive, if the thread is not properly installed when the student installs it, it is easy to fall to the ground and cause the lens to be damaged. Therefore, for the sake of safety, it is emphasized that the student should install the objective lens Hold the objective lens with the index and middle fingers of your left hand, and then attach the objective lens with your right hand so that it will not fall to the ground even if it is not installed properly. 2. The problem of correct light alignment Light is a very important step when using a microscope. When aiming light, some students randomly turn an objective lens to face the light hole instead of using a low-power lens as required. I like to use one hand when turning the mirror, and I often pull the mirror down. Therefore, when instructing students, teachers must emphasize the use of low-power lenses to point the light. When the light is strong, use a small aperture and flat mirror, and when the light is weak, use a large aperture and concave mirror. The mirror should be rotated with both hands. Until the uniformly bright circular field of view. Do not move the microscope randomly after the light is aligned, so as to prevent the light from accurately passing through the reflector and entering the light hole. 3. The problem of using the quasi-focus spiral correctly. Using the quasi-focus spiral to adjust the focal length and finding the object image can be said to be the most important step in the use of the microscope, and it is also the most difficult step for students. Students are prone to make the following mistakes during the operation: one is to adjust the focus directly under the high-power lens; the other is that the eyes are always looking into the eyepiece regardless of whether the lens barrel rises or falls; the third is that they do not understand the critical value of the object distance. When the distance is adjusted to 2 to 3 cm, it is still being adjusted upward, and the speed of turning the collimating screw is very fast. The first two errors often cause the objective lens to interfere with the mounting and damage the mounting or lens, while the third error is the most common phenomenon when students use a microscope. In response to the above errors, the teacher must emphasize to the students that the focal length must be adjusted under a low-power lens. First, turn the coarse collimation screw to slowly lower the lens barrel. The objective lens is close to the glass slide, but be careful not to let the objective lens touch the glass slide. During this process, the eyes should look at the objective lens from the side, and then look into the eyepiece with the left eye, and slowly reversely adjust the coarse collimation screw to make the lens barrel rise slowly until the object image is seen. At the same time, explain to the students Generally, the object distance of the microscope is about 1 cm, so if the object distance is far more than 1 cm, but the object image is still not seen, it may be that the specimen is not in the field of view or the rotation speed of the coarse focus screw is too fast, and it should be adjusted at this time. Set the film position, and then repeat the above steps. When a blurred object image appears in the field of view, it is necessary to switch to the fine focus screw adjustment. Only in this way can the search range be narrowed and the speed of finding the object image can be increased.