Optical Glass with Low Refraction Index

摘要

A glass is described containing by weight, SiO2, 26 to 80%; Al2O3, 7 to 40%; KF, 4.5 to 36% and in excess of 100% by introduction of F up to 6% by weight. This provides a glass of a lower refraction index of 1.4273 to 1.5000, and having a medium dispersal of 0.00600 to 0.00805 with a dispersal coefficient in a range of 71 to 62. A glass of this type may contain a small quantity of other substances which do not materially affect its basic properties. The glass in question is cooked by the ordinary technological process and its manufacture is accomplished by pressure, blowing, bending and other known methods. (Author)