crown glass
English edit
Etymology edit
So called from a crown-like shape given to it in the process of blowing.
Noun edit
crown glass (usually uncountable, plural crown glasses)
- 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.
- (optics) 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.
- The convex half of an achromatic lens is composed of crown glass.
Translations edit
type of window glass
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variety of optical glass
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See also edit
Further reading edit
- Crown glass (window) on Wikipedia.Wikipedia
- Crown glass (optics) on Wikipedia.Wikipedia