| 摘要 |
PURPOSE:To avoid generation of a flaw and improve strength against break of glass by interposing an impact absorbing film on at least a contact portion between the seal portion of an electric bulb and metallic case. CONSTITUTION:A part of a seal portion 4 is concave and there are a few projections 6 to 6''' which are roundish inside in a part of a metallic inside case 3. And these projections are fitted into concave portions of a seal portion 4 respectively, thereby fixed by a metallic outside case 2. And an impact absorbing film 7 such as a silicone is interposed between the concave portion of the glass seal portion 4 and the projections 6 to 6''' of the metallic inside case. As an impact absorbing film 7, it is desirable to have fast drying performance. And other than silicone, a plastics system available in the daily market is good as well. Efficient thickness of the film is greater than 0.05mm.. The area in which the impact absorbing film 7 is provided can be arranged at other than the fitting portion. Further, it is preferable that the film 7 is previously provided in the concave portion of the glass seal portion 4 or on the surface of the projections 6 to 6''' of the metallic inside case 3 or in both of them. |
