阿貝數 (abbe number) - 眼鏡

Abbe Number

In physics and optics, the Abbe number, also known as the V-number or
constringence of a transparent material, is a measure of the material's
dispersion (variation of refractive index with wavelength). It is named for
Ernst Abbe (1840-1905), the German physicist who defined it.

The Abbe number V of a material is defined as:

V=(nD-1)/(nF-nC)

where nD, nF and nC are the refractive indices of the material at the
wavelengths of the Fraunhofer D-, F- and C- spectral lines (589.2 nm, 486.1
nm and 656.3 nm respectively). Low dispersion materials have high values of V.

Abbe numbers are used to classify glasses. For example, flint glasses have
V<50 and crown glasses have V >50. Typical values of V range from around 20
for very dense flint glasses, up to 65 for very light crown glass, and up to
85 for fluor-crown glass. Abbe numbers are only a useful measure of
dispersion for visible light, and for other wavelengths, or for higher
precision work, the group velocity dispersion is used.

以上摘取自 http://www.answers.com/topic/abbe-number

文中提到螢石的阿貝數極高，對相機有些興趣的，知道Canon對於
自家高檔鏡頭L鏡都會用fluorite來減低色散，那一般市面上的鏡
片有使用這種材質來製造嗎?如果沒有是因為價錢的因素無法量產
還是本身技術無法實行呢?
感謝回答

※ 引述《TOUCH99 ( )》之銘言：
: 前幾篇那個推文講到一些有關阿貝數(ABBE NUMBER)的事情
: 發現板上好像沒有相關文章,我根據我的認知拋磚引玉的大家來討論一下!!
: 阿貝數和折射率都是光學上兩個相當的重要的參數!!
: 折射率大家有學過國中理化的應該都清楚,折射率對你的眼睛會產生什麼作用
: 阿貝數就是對同一個眼睛對於不同頻率的光會產生不一樣的折射率
: 大家常說的色散就是因此而產生的!!另外阿貝數越大越不容易產生色散
: 一般說來樹酯鏡片有很多曲折率,曲折率越大,阿貝數越小
: 這個問題一直是目前各大光學廠想要努力改進的目標,一般說來阿貝數40以上就算很好了!
: 玻璃鏡片的阿貝數通常也比安全鏡片高一些 XD

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