crown glass

名词 n.
中文释义

英文释义

名词 n.
  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. uncountable,usually
  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. uncountable,usually
    — The convex half of an achromatic lens is composed of crown glass.

词形变化

crown glasses plural

词源

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