| 摘要 |
PURPOSE:To prevent abnormally narrow distance between the electrodes and the wall of the emitter tube and achieve improved characteristics of a small-type high pressure metallic vapor discharge lamp by restricting angles of the inner end surfaces of the sealing sections of the emitter tube seen from two directions. CONSTITUTION:Angle (theta1) of the inner end surfaces 6 of the sealing sections 1A and 1B of an emitter tube seen from the expanded surface (1Aa) of the sealing sections 1A and 1B and angle (theta2) seen from the side surface (1Ab) of the sealing sections 1A and 1B are adjusted according to the formula (I). As angle (theta1) is large, it is possible to avoid too narrow distance between the electrode and the tube wall. The small magnitude of angle (theta2) is advantageous to temperature increase of the coldest area. Furthermore, the large magnitude of angle (theta1) prevents the sealing sections 1A and 1B from becoming as large as those of a conventional lamp. As a result, it is possible to reduce the loss of heat from the sealing sections 1A and 1B, thereby increasing the temperature of the coldest area and achieving improved characteristics of the lamp. |
