| 摘要 |
<p>PURPOSE:To prevent the occurrence of strong discharge in a base and the damage an outside power supply means due to the discharge, by providing the base with a hole to connect the inside and outside of the base to each other. CONSTITUTION:The hole 10 is opened through the circumferential wall of and insulator cylinder 8 to connect the inside and outside of the base 3 to each other. If the fall in the degree of vacuum in the outer tube 1 due to the damage of a luminous tube 2, the discharge in the outer tube due to the vacuum degree fall or the rupture of a sealed-up part 5 of the outer tube 1 due to the discharge has occurred, the external air enters into the base 3 through the hole 10 to prevent the pressure in the base 3 from drastically falling. Thus, the discharge which might occur in the base 3 or be transferred from the outer tube 1 into the base 3 is suppressed low and the damage is limited very low.</p> |
