GLASS COMPOSITION FOR A LAMP, GLASS PART FOR A LAMP, LAMP, AND ILLUMINATION DEVICE

摘要

A glass composition contains the following constituents expressed in terms of oxides: 65wt% to 75wt% of SiO2; 1wt% to 5wt% of Al2O3; 0.5wt% to 5wt% of Li2O; 5wt% to 12wt% of Na2O; 3wt% to 7wt% of K2O; 12wt% to 18wt% of Li2O + Na2O + K2O; 2.1wt% to 7wt% of MgO; 2wt% to 7wt% of CaO; 0wt% to 0.9wt% of SrO; 7.1wt% to 12wt% of BaO; and substantially no PbO. The glass composition for a lamp is substantially lead-free, has an electrical insulation suitable for an illumination purpose, and further reduces the risk of devitrification.