| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve a mechanical strength of end walls on a glass tube being self-sealed, and to reduce failure rates of lamp in manufacturing processes and in market places. SOLUTION: A portion 4, which is to be cut, of a glass tube 1 is heated and softened while a straight shape of a glass tube is rotated, and then the glass tube 1 is moved toward the portion 3 during the heating of the portion 3 such that a thicker portion 8 is formed at the portion 3, and thereafter, the portion 3 of the glass tube 1 is cut while the glass tube 1 is starched in a direction opposed to the portion 3. Therefore, one end of the glass tube 1 is self- sealed and formed.</p> |
