| 摘要 |
PURPOSE:To stabilize the characteristic of a metal vapor electric-discharge lamp without using any heat-insulating metal belt by making the outer diameter of at least one end of a ceramic emission tube to be smaller than the outer diameter of the central side of the emission tube. CONSTITUTION:Each end part of a ceramic emission tube 1, the central side of which has an outer diameter of (D), has an outer diameter of (D1) and a length of (L1). The above diameter (D1) and the above length (L1) are adjusted so that they satisfy the relationships of D1/D<=0.8 and L1/L<=0.2, that are within the range of the critical point of the emission tube 1. As the result, a stable characteristic of the lamp can be achieved without using any heat-insulating metal belt. |
