crown glass

短语

[化] 冕玻璃; 冕牌玻璃

词形变化

crown glasses 复数 crown glasses

释义与例句

n.
  1. 1.

    An early type of window glass made by blowing glass into a hollow globe (crown) and then flattening it on a punty, reheating and spinning out into a flat disk by centrifugal force.

    不可数
  2. 2.

    A variety of glass used in lenses and other optical components due to its low refractive index and dispersion. Originally crown glass was made from alkali-lime silicates with approximately 10% potassium oxide, but similar properties may be attained with other recipes.

    不可数 工程 物理

    The convex half of an achromatic lens is composed of crown glass.

词汇关系

名词

上位词 2

glass optical glass

词源

So called from a crown-like shape given to it in the process of blowing.

来源：wiktionary