Glossaire
A-D
- Abbe number
The Abbe number, also known as the V-number or constringence evaluates the material dispersion. It is measured with the Abbe number, which can vary between 20 and 90. The smaller this number and the more dispersive the material.
- Coverslip
Thin glass slide placed on top of a preparation in order to protect it. It has a normalized thickness of 0.170mm.
- Diascopic light microscopy
Transmitted light microscopy, used to observe transparent object (with transmission illumination).
E
- Episcopic light microscopy
Reflected light microscopy, used to observe opaque objects (with a reflected illumination).
- Eye relief
Distance between the microscope exit pupil and the ocular surface closest to the eye.
- Eyepoint or Ramsden disc
Exit pupil of the microscope, located at one or two centimeters behind the last surface of the eyepiece, and where the eye pupil has to be placed.
F-Z
- Objective
Converging optical system forming a magnified image of the object under observation. It usually has a large numerical aperture (in the object space) so that the microscope can resolve details of size close to the wavelength.
- Ocular or Eyepiece
Converging optical system that transforms the intermediate image formed by the objective into a virtual image located at the infinity to be observed by the eye.
- Resolution Power
Capacity of an optical instrument to distinguish between two objects that are really close to each other. The higher the resolution power, and the smaller the resolution limit (the distance between the two objects).
- Working Distance
Distance between the object under observation and the frontal lens of the objective. It is usually of several tenths of millimeters for the current high magnification objectives.