| abstract |
An envelope used for producing an external electrode fluorescent lamp which has a structure wherein an electrode is formed on the external surface is characterized by being composed of a glass having a dielectric loss tangent of not more than 0.02 at 40 KHz and 250°C and a strain point of not more than 650°C. Specifically, the glass is composed of an aluminoborosilicate glass having a chemical composition including, in mass percent, SiO 2 : 35-65%, B 2 O 3 : 0.1-25%, Al 2 O 3 : 2-20% and Li 2 O + Na 2 O + K 2 O: 0.1-5%, or a chemical composition including, in mass percent, SiO 2 : 35-65%, B 2 O 3 : 0.1-25%, Al 2 O 3 : 2-12.5% and Li 2 O + Na 2 O + K 2 O: from 0% to less than 0.1%. |