a type of low density glass.
One of the most suitable and common types of glass used in optics and often used in conjunction with flint glass (they are of different refractive indices) to make up achromatic lenses. Lighter plastic equivalents of crown glass used for spectacle lenses are Perspex acrylic and CR39.
a method of producing glass in which a globe is transferred from the blowpipe to a pontil or punty, reheated and then spun until it opened up into a large flat plate - a table of crown glass. It often has a greenish tinge, curves slightly and can have small radial imperfections, all of which can give the glass a wonderful reflective quality. While more costly to produce through the wastage associated with its circular shape, because it does not come into contact with any surface during manufacture, it is more transparent than cylinder glass.
Sheet glass made by blowing a parison, cutting it open, and rotating it rapidly, with repeated reheating, until the centrifugal force has caused it to become a flat disk. After annealing, the disk is cut into panes of the required shape and size. " Bull's eye" panes come from the centers of the disks and preserve the thickened area where the parison attached to the pontil.
Rotating the glass as it is blown, a by product is a disk shape with a crown, in the center. This is also called a Roundel.
A source of most window glass, produced by blowing and then spinning molten glass into a large flat disc.
Usually refers to ophthalmic glass of refractive index 1.523.
low dispersion optical glass.
Crown glass is glass that contains no lead oxide. Some fake rhinestones are made from crown glass.
Crown glass was an early type of window glass. In this process, glass was blown into a "crown" or hollow globe. This was then flattened by reheating and spinning out the bowl-shaped piece of glass (bullion) into a flat disk by centrifugal force, up to 5 or 6 feet (1.5 to 1.8 metres) in diameter.
Crown glass is type of optical glass used in lenses and other optical components.