| 摘要 |
PURPOSE:To prevent the generation of cracks by adding Al2O3, CaO, and SrO in the constituents of sealing glass frit, sealing them at a high temperature, and forming the sealing section of an alumina luminous tube so that the maximum diameter of a crystal in glass and a sealing gap can have a specific relationship. CONSTITUTION:Sealing sections are provided at the respective specified locations between an alumina luminous tube 1 and caps 2 fit on both ends of said tube and between both caps and electrodes 4 and electric induction terminals 3 that are inserted in the caps. In addition, when Al2O3, CaO, and SrO are added to the constituents of sealing glass frit and they are sealed at a high temperaure and then the maximum diameter of a crystal in glass is (d) and the sealing gap is D, the sealing section is formed so that both relationships are set to d<=D/2 and D<=0.4m/m. As a result, a discharge lamp with long life span can be obtained without damaging the life span caused by the generation of cracks in the sealing section. |
