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White light consists of electromagnetic waves, the period lengths of which total 400 to 700 nm.
It is important to know that:
1 mm = 1000 µm
1 µm = 1000 nm
Light of green color has a wavelength of 550 nm which
corresponds to 0.55 µm.
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| Aperture | Increasing Resolution (1) |
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| Increasing Resolution (2) |
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To enable two objectives to be compared, the “numerical aperture” has been defined: this is a measure of the solid angle covered by an objective.
The following definition is made:
N.A. = n · sin α
N.A. is the Numerical Aperture, α is half the opening angle of the objective and n the refractive index of the immersion medium used between the objective and the object. (n = 1 for air; n = 1.51 for oil or glass)
continue with: Measurement
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