| 释义 |
crown glass
crown glassn.1. A soda-lime optical glass that is exceptionally hard and clear, with low refraction and low dispersion.2. A form of window glass made by whirling a glass bubble to make a flat circular disk with a lump left in the center by the glass blower's rod.crown glass n 1. (General Physics) another name for optical crown 2. (Building) an old form of window glass made by blowing a globe and spinning it until it formed a flat disc crown′ glass`
n. 1. an optical glass of low dispersion and generally low index of refraction. 2. an old form of window glass formed by blowing a globe and whirling it into a disk. [1700–10] Thesaurus| Noun | 1. | crown glass - a glass blown into a globe which is later flattened and spun to form a diskglass - a brittle transparent solid with irregular atomic structure | | 2. | crown glass - optical glass of low dispersion and low refractive indexoptical crown, optical crown glassoptical glass - clear homogeneous glass of known refractive index; used to make lenses |
Crown glass
crown glass[′krau̇n ‚glas] (materials) A soda-lime glass, typically having 72% SiO2, 13% CaO, and 15% Na2O, which is hard and will take a simple polish; highly transparent for visible light. Crown glass1. An early form of window glass, cut from blown disks.2. The glass made by blowing a mass of molten material, which is then flattened into a disk and spun into a cular sheet. See also: glasscrown glassA handmade glass of soda-lime composition, used for windows; manufactured in the early 19th century by a now-obsolete process in which a hollow sphere of glass was blown while still very soft, then spun to form a large, nearly flat circular disk. During the spinning process, ripple lines were formed in a pattern of concentric circles, with their center at the center of the spun disk; this central area was used in a bull’s eye window. Also see glass.crown glass
crown glassa compound of lime, potash, alumina, and silica; commonly used in lenses; has a low dispersion (52.2) relative to index of refraction (1.523).crown glass
Synonyms for crown glassnoun a glass blown into a globe which is later flattened and spun to form a diskRelated Wordsnoun optical glass of low dispersion and low refractive indexSynonyms- optical crown
- optical crown glass
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