| 摘要 |
PURPOSE:To provide a solenoid magnetic field type double tube discharge lamp wherein an inner edge of a high frequency exciting coil can be brought close to an outer tube to enhance magnetic connection. CONSTITUTION:A luminous substance is enclosed in a luminous tube 10 which is also housed in an outer tube 1 to form a double tube structure, a high frequency exciting coil 20 is arranged around the outer tube 1 and plasma discharge is generated by this high frequency exciting coil 20 in the luminous tube 10 so as to emit light. In this solenoid magnetic field type double tube discharge lamp, an end of the outer tube 1 is crushed for sealing and a width dimension (w) of this sealing part 2 is set smaller than an outer diameter D of the outer tube 1. Since the width dimension (w) of the crushed sealing part 2 formed at the end of the outer tube 1 is set smaller than the outer tube diameter D, the outer tube l can be easily passed through the high frequency exciting coil 20, an inner periphery of the high frequency exciting coil 20 can be brought into proximity of the outer tube 1 to enhance magnetic connection between the high frequency exciting coil 20 and the plasma discharge and efficiency can be improved. |
