Microscope best use technology sharing
1. The accuracy consideration of the conversion plate of the microscope is based on the positioning accuracy and parfocal accuracy as the standard
1. Positioning accuracy: It means that when the objective lens is in working condition, the converter (converter disk) must be clear and stable. Its field of view center must be equal to the offset of the field of view center when other objectives are in the same working state. Divergent. In other words, whichever lens is converted, it should be at the same position without any offset.
Positioning accuracy adjustment and observation: After the objective lens is converted by the converter, use objective lenses with different magnifications to observe the misalignment of the optical axes of the objective lens. After focusing with the 10× objective lens, take its center as the reference, and then switch to the 40× objective lens, the center shift must not exceed 2/3 of the radius of the field of view, and use the 40× objective lens as the reference to switch to the 100× objective lens , the center displacement shall not exceed 3/4 of the radius of the field of view. The higher the precision of the microscope, the smaller the displacement. Advanced research microscopes are even different. This is one of the standards for considering the quality of the microscope, and it is also a standard for considering the user's level. Why? You say that? 80% of our users twist the lens with their hands to change the magnification. This operation has been done many times for a long time, resulting in damage and loosening of the connecting thread of the lens, which destroys the effect of its precision. The correct use is to change the lens by holding the conversion plate (with stripes engraved on it), so as to maintain the positioning accuracy of the microscope.
2. Parfocal accuracy: refers to a microscope objective lens, after adjusting it in a working position, and then switching to another lens, you should be able to see the object image without readjusting the focal length. For example, when observing from a low magnification lens to a high magnification lens, the outline of the specimen can still be seen, and the accuracy is within 0.03mm. It can be observed clearly when the focus is allowed, otherwise the parfocal accuracy is not enough. The observation of the oil lens can not be parfocal with its lens. Due to the different media, one is a dry system and the other is an oil immersion system. But be careful not to let the lens touch the cover when changing the oil lens. If it does, it means that the thickness of the cover exceeds the specified thickness, which is a substandard product. The cover thickness requirements should be clearly written on the oil lens. ,
3. The connection between the design of the objective lens and the transfer disc, and the error is considered based on the contour conversion: it is also an indicator to consider whether the user's operation is correct or not.
Contour conversion: when switching from a low magnification lens to a high magnification lens, assuming that the objective lens is the original configuration of the microscope, and all slides and coverslips fully meet the standard requirements. Free "contour conversion" can be aborted. That is to say, the converter is used to directly rotate the high-magnification lens into the optical axis, and only need to adjust the micro-adjustment slightly to observe the object clearly. If this state cannot be reached, it is necessary to check whether the thickness of the cover glass and slide glass exceeds the standard. If there is no problem with these two items, the design of the microscope must be considered, and it must be dealt with by contacting the manufacturer. The author found similar problems in the inspection and acceptance of 130 Japanese microscopes in the China-Japan Hospital under construction. If the user is using the microscope, when changing the lens, instead of holding the conversion disc, he usually holds the objective lens to change the observation magnification. For example, if a low-magnification lens is switched to a high-magnification lens, he should twist the lens to stop the conversion. In fact, it is a kind of It is a common operation error. Long-term use of this method will lead to deviations in the matching accuracy of the threaded thread of the lens and the conversion plate, which will cause the deviation of the contour conversion, which not only affects the observation but also makes the microscope unusable. The author has conducted a survey of users on this issue, and about 90% of them use it in this way, which shortens the service life of the microscope. I bought a microscope myself, and I still use it every day after retirement. After 30 years, the microscope is still working at its maximum effect.
4. Fine-tuning, focusing and indexing calculation: We cannot do without the use of microscopes every day, and we turn a blind eye to fine-tuning when looking at specimens, and never think about indexing calculations. The total adjustment distance of the fine-tuning is generally 1.8~3 mm, often 2 mm (on the fine-tuning handwheel, you can see the scale), controlled by the fine-tuning handwheel, rotating the handwheel, the optical system can move very slowly. If the adjustment distance of rising or falling is 2 mm, assuming that the hand wheel rotates 15 times, 50 divisions per week, then each adjustment division, the distance of rising or falling of the optical system is: 2 mm ÷ (15 × 50 )=0.0027mm=2.7μm. This allows the thickness of tissue specimens to be measured using fine-tuning graduations.
5. The error of fine-tuning: the fine-tuning is within the range of focusing. When turning the handwheel, the object image should not shake or shake. Even if it exists, the maximum swing angle should not be >1; Within the range of depth of field, rotate the fine-tuning handwheel, and the plane position displacement of the object is 0.05 mm; the fine-tuning is rising and falling, and the handwheel rotation should allow continuous and uniform movements, and there should be no stagnation, pause or beating attacks. If it occurs, it means that the microscope has a defect. In the gear part, if the newly purchased microscope shows that the precision error is large, it is a substandard product.
6. Coaxial adjustment is the central adjustment: it is an important indicator to consider the operator's understanding of microscope knowledge and whether he can operate it; it is an important element to maximize the performance of the microscope; it is also a standard for checking whether a microscope is qualified.
Alignment adjustment: Make the main optical axis of the eyepiece, objective lens and condenser and the center of the iris diaphragm coincide completely on a straight line, which is called optical alignment. If the optical axis does not match or is not correct, it will increase the aberration and coma of the object image, resulting in a decrease in the resolution and clarity of the observed object.
Coaxial adjustment is mainly to adjust the position of the condenser, because the eyepiece and objective lens have been adjusted before leaving the factory. There is no optical axis adjustment screw on the condenser on some microscopes (old-fashioned microscopes), you can twist the condenser to adjust the optical axis. In modern microscopes, there is an optical axis correction screw on both sides of the condenser bracket. The right and left hands can screw these two screws to adjust the alignment, so that the condenser, objective lens, and eyepiece can be adjusted on the same optical axis. Axis adjustment. In addition, some microscopes have three top screws at an angle of 120 degrees apart on the bracket of the condenser, one of which is equipped with a spring and can be stretched, and the other two are screws that can be rotated. Adjust the three screws to make the condenser The position of the device moves in the horizontal plane, so as to stop the adjustment of the optical axis and stop the alignment. If the alignment is not good or the alignment is not on, it is necessary to check whether the fixing screws of the grating are loose and the positioning of the converter is out of order.
Adjustment method: put the specimen on the stage, and focus with a 10× objective lens. Open the condenser grating completely, adjust the angle of the beam splitter to make the brightness of the field of view the brightest, close the grating to the minimum, move the condenser up and down, and narrow the field of view to focus on the specimen. Assuming that the contraction image of the field of view is not in the middle, you can adjust the optical axis correction screw of the condenser to make the matching concentric. Change the objective lens to 40×, adjust the size of the grating, so that the original shrinkage image in the field of view is almost equal to the field of view. If it is still in eccentricity, it is necessary to turn the screw of the condenser to achieve the correct alignment. In addition, it can also be used to unplug the eyepiece and observe directly from the top of the lens barrel. When the grating is closed to the minimum, the image of the grating hole only needs a bright spot, which just falls on the center of the objective lens, and it can be qualified. If not, you can adjust the following condenser adjustment, observe the light deviation and stop the adjustment.
Explanation: 1. Shaft adjustment makes the field of view images overlap; 2. Adjusts the size of the light of the condenser to be consistent.
7. Pupillary distance adjustment: most hospital microscopes are currently binocular microscopes, and you must first adjust the pupillary distance when using them. Some students asked me: "Mr. Cao, why do I have a headache after reading the microscope? I feel very uncomfortable?" I told him, "It's because you didn't adjust your pupillary distance properly. I will teach you how to adjust the pupillary distance. !"
There is an adjustment device on the microscope, because the pupillary distance of each observer is different, so the pupillary distance must be adjusted first when using it. The picture is just like the pupillary distance must be measured for you when configuring glasses. When we look at a microscope, we must first adjust the pupillary distance. The distance between the two eyepieces can be adjusted by extending the parallel line. Generally, the number 53~73 is engraved on the frame supported by the eyepiece, which is the symbol number for adjusting the interpupillary distance. During the adjustment process, the position of the image plane of the object image changes. Some microscopes can automatically compensate for this change, and most of them need to be compensated manually. That is, read the value of your pupil distance from the scale value engraved on it, and then Turn the sleeve of the right eyepiece so that the reading on it is consistent with the value of the interpupillary distance, then use the right eye to focus and find the object, and then rotate the sleeve of the left eyepiece so that the images of the left and right eyes overlap and the focus is different. After this adjustment, not only can the parfocal accuracy of the objective lens be guaranteed, but also the observer will not look beautiful after long-term use, and it can protect eyesight.
