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 文中提到萤石的阿贝数极高，对相机有些兴趣的，知道Canon对於 自家高档镜头L镜都会用fluorite来减低色散，那一般市面上的镜 片有使用这种材质来制造吗?如果没有是因为价钱的因素无法量产 还是本身技术无法实行呢? 感谢回答 ※ 引述《TOUCH99 ( )》之铭言： : 前几篇那个推文讲到一些有关阿贝数(ABBE NUMBER)的事情 : 发现板上好像没有相关文章,我根据我的认知抛砖引玉的大家来讨论一下!! : 阿贝数和折射率都是光学上两个相当的重要的参数!! : 折射率大家有学过国中理化的应该都清楚,折射率对你的眼睛会产生什麽作用 : 阿贝数就是对同一个眼睛对於不同频率的光会产生不一样的折射率 : 大家常说的色散就是因此而产生的!!另外阿贝数越大越不容易产生色散 : 一般说来树酯镜片有很多曲折率,曲折率越大,阿贝数越小 : 这个问题一直是目前各大光学厂想要努力改进的目标,一般说来阿贝数40以上就算很好了! : 玻璃镜片的阿贝数通常也比安全镜片高一些 XD -- 爱钱的女人只给凯子摸 不懂得用保险套的人别嫌孩子多 金钱力量虽大　却生不带来死不带走 --

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