Dioptre

Sciences > Physical > Optical

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In Optical, the dioptre is a homogeneous unit of Vergence contrary a length. The symbol of dioptre is the Greek letter $\backslash \; delta$ (delta).

Thus, a lens of a vergency of $20\; \backslash \; delta$ will have a focal distance image of 5  centimetres (one twentieth of meter).

The interest of dioptre lies in the simplification of certain calculations, for example with the formula of Descartes making it possible to find a relation between the distance object p, the distance image p' and vergency C of a thin lens, given by: $\backslash \; frac\; \{1\}\; \{p\text{'}\}\; -\; \backslash \; frac\; \{1\}\; \{p\}\; -\; C\; =\; 0$

It is also in this unit that the Ophtalmologue S characterize the defects of vision of their patients.

See too

• Optical geometrical

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