crown glass


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crown glass

a compound of lime, potash, alumina, and silica; commonly used in lenses; has a low dispersion (52.2) relative to index of refraction (1.523).
References in periodicals archive ?
Lens material Abbe Number Crown Glass 58 CR39 58 Trivex 43 1.
53--is closer to that of crown glass than other thermoplastics; thus, their use in place of glass requires minimal design changes.
Extreme made its mark by producing some of the most respected target scopes in the business, employing German-engineered crown glass with world-famous Zeiss multilayer, non-reflective coatings for scratch resistance, crystal-clear target image and superior low-light performance.