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Physics · 术语表

什么是 Vergence?

又称: diopter

Definition 10.3 High School Physics · 第 10 章 — Lenses, Images, and the Eye

The vergence of a lens of focal length f′f' (in meters) is C=1/f′C = 1/f', measured in diopters (symbol D): 1 D=1 m−11~\text{D} = 1\,\mathrm{m}^{-1}; diverging lenses have C<0C < 0. Opticians prescribe in diopters: vergences of thin lenses in contact simply add (admitted here; derived in the Year 1 volume).

示例

Example 10.4 (Reading a prescription)

A lens with f′=0.50 mf' = 0.50\,\mathrm{m} has C=1/0.50=+2.0C = 1/0.50 = +2.0 D: converging. A −4.0-4.0 D prescription means f′=−0.25 mf' = -0.25\,\mathrm{m}: diverging, focal length 25 cm25\,\mathrm{cm}.

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