Flinting Glass
Flinting Glass is referred to as F glass. One of the two major types of colorless optical glass has greater dispersion than the other type of crown glass (K glass). It is customarily divided into light flint, flint, heavy flint, barium flint, heavy barium flint, lanthanum flint, heavy lanthanum flint, titanium flint and special flint according to density or composition characteristics. Most of them contain PbO. The narrowly defined flint glass belongs to the Na2O-K2O-PbO-SiO2 system, and the mass fraction of PbO is between 40% and 55%. The refractive index and density increase with the increase of PbO content. Mainly used as a material for optical parts in optical instruments, such as Spherical Lenses and Cylindrical lenses.
By modifying the glass formula, the optical glass without lead, arsenic and cadmium and other radioactive elements is expressed by a prefix "H-" indicating its envioronment-friendly characteristics, for example: H-F4
