First, the match on the category. That is, all flat field objectives must be used with a special flat field eyepiece .
Second, a reasonable match of magnification. At a certain magnification, the objective lens and the eyepiece can be arbitrarily combined, but the premise of the combination is mainly to consider the effective magnification, which is an important rule for the correct use of the microscope ( Microscope ). The effective magnification of the microscope ( Microscope ) is 500 to 1000 times the numerical aperture of the objective lens, that is, the product of the magnification of the objective lens and the eyepiece is equal to 500 to 1000 times the numerical aperture of the objective lens.
If you use a 40X objective with a numerical aperture of 0.65 to observe the specimen, how big should you choose?
First, the effective total multiple is determined according to the effective magnification, and then divided by 40 , that is , the multiple of the eyepiece should be selected. The calculation process is: ( 0.65 × 500 ~ 0.65 × 1000 ) ÷ 40 ≈ 8 ~ 16 . That is to say: an objective lens with a numerical aperture of 0.65 should be matched with an eyepiece of 8 to 16 times in the range of effective magnification ( 500 to 1000 times) . If the eyepiece magnification is too low, the total magnification is too small, the resolution of the objective lens cannot be fully utilized, and the details that could have been identified, because the total magnification is too small, it is difficult to distinguish when squeezed together. The magnification obtained by the eyepiece above 16 times is called “empty magnificationâ€. The resolution of the influence details is not improved at all, but the depth of clarity is small and cannot clearly reflect the structure of different levels.
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