| 摘要 |
PURPOSE:To prevent any cracks which might be caused around a sealing area due to the phenomenon that the temperature of a stem becomes higher than that of an outer tube by causing compressive strain to remain in the outer tube during its formation before the stem is fused to the outer tube to make a tubular bulb. CONSTITUTION:A lamp bulb is made by fusing a disk-like stem 2 to the opened end of an outer tube 1 formed by glass. In the lamp bulb, an inner tube 3 one end of which is open and filaments 4 fixed to the stem 2 through sealed wires are installed, thereby constituting a compact fluorescent lamp. During the time when the outer tube 1 is gradually cooled after it is formed at high temperature, the inner area is caused to cool more rapidly than the outer area so as to cause compressive strain to remain in the outer tube 1. As a result, during the ignition of the lamp, the temperature of the stem 2 becomes higher than that of the outer tube 1 causing temperature difference around a sealing area (A). The tensile strain of the outer tube 1 caused due to the temperature difference can be absorbed by the compressive strain, thereby preventing any generation of cracks or the like. |
