| 摘要 |
PURPOSE: To temporarily avoid or completely eliminate blackening of a glass bulb which limits the lamp life by forming a fine particle structure by forging and compressing the front part of a truncated cone of an anode element in the axial direction. CONSTITUTION: An anode element is heated at about 1400 deg.C in an electric furnace and hit by a forging hammer. The applied deformation and compression is carried out from the outer face in the outer face and following the degree of the compression, heat resistant creeping property and heat conduction function are decreased toward the rod center from the outer face of a material rod. Consequently, in the center region of an anode end face which forms an arc center part and where the maximum temperature is observed, the degree of the compression has the minimum in the center region. As a result, intense W evaporation and blackening of a glass bulb which is caused by evaporated W and limits the lamp life are temporarily avoided or completely eliminated. |
