何謂阿貝數??

Question

想知道阿貝數跟鏡片的關係~~~~
何謂阿貝數~~~~~~~
阿貝數大是好是壞~~~~~~

Answer 1

阿貝數 ( Abbe Number) 是用來評估一個光學系統色散能力好壞的數值他和折射率 ( Refration Index ) 可以說是光學設計上兩大重要的參數如果你有耐心, 英文不錯..就看看下面轉貼的資料吧                 (From:http://www.answers.com/topic/abbe-number)如果你只是想要簡單的知道....那就稍微聽聽小弟敘述吧....    簡單的說....就是不同頻率的光線對同一個光學系統而言,    會有不一樣的折射率, 這就是色散的來源.....    為了評估色散問題, 德國的科學家 Ernst Abbe (1840-1905)    就定義了系統在三個波長下光線的折射率    分別為 859.2nm , 486.1nm, 656.3nm 時的折射率    並定義了下面那個公式來評估這折射率差    一般來說, Abbe Number越大, 表示系統越不容易產生色散    因此系統算是越好了.....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). Named for Ernst Abbe (1840-1905), German physicist.The Abbe number V of a material is defined as:
圖片參考：http://content.answers.com/main/content/wp/en/math/18356858292e4b2389c6f075f8cd9893.png
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 60 for very light 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.