Biological microscope eyepiece micrometer formulae
When using a biological microscope, it is sometimes necessary to measure the length of the observed object. Since the object under observation is very small, it is impossible to measure it directly with conventional measuring tools, which is why we need to use a microscope-specific micrometer. To measure the length of the object to be examined, you need to use two tools, one of which is mounted in the eyepiece, known as the eyepiece micrometer; a piece of the carrier stage, is a special coverslip, you can see in the middle of a small circular area, which is engraved with a very small scale, the general total length of 1mm, a total of 100 cells, that is, the distance between each cell is 10um, it is the role of determining the length of the object. It is used to determine the length of the eyepiece micrometer under the biomicroscope.
In use, we need to first eyepiece micrometer into the eyepiece tube, the specific operation is: first pull the eyepiece from the microscope down, away from the lens (that is, we usually look at the place of observation) at the end of a gear-shaped circular structure, unscrewing it, and then the eyepiece micrometer into which, pay attention to the front side of the field of view should be put on the diaphragm, and then screwed back to the eyepiece will be put back. Some microscopes are not allowed to be disassembled due to their precise structure, and need eyepieces specially equipped with micrometer rulers. Then put the micrometer ruler on the carrier stage, adjust the focus of the microscope to know that you can see the clear scale of the ruler. At this point, adjust so that one end of the two rulers in the whole scale overlap, and then look for the other end of the overlap in what place, count the number of their overlap part of the grid will be able to calculate the eyepiece microscope micrometer in the case of magnification of the actual magnification.
The specific formula is as follows:
Eyepiece micrometer per frame = (number of overlaps of the table ruler X 10) ÷ number of overlaps of the eyepiece ruler. As shown above, the overlap of the table scale is 4 frames, and the overlap of the eyepiece micrometer is 10 frames. From this, you can calculate the length of the eyepiece micrometer per grid: (4X10)/10 = 4um.
After determining the length represented by each cell of the eyepiece micrometer, remove the table ruler and use it later to determine the actual length of the object being examined. Since the biological microscope has several objective lenses, each with a different magnification, the actual length represented by the eyepiece micrometer is different at different magnifications, so it should be recalibrated when switching the magnification.
