Re: [閒聊] 阿貝數 (abbe number)

看板optical (眼鏡)作者cokecolass時間18年前 (2006/06/19 13:38)推噓2(2推 0噓 3→)

留言5則, 3人參與討論串2/2 (看更多)

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 -- 愛錢的女人只給凱子摸不懂得用保險套的人別嫌孩子多金錢力量雖大　卻生不帶來死不帶走 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 210.85.106.222