| 摘要 |
PURPOSE:To remove swelling of the sealing part by gradually heating to perform sealing process so as not to produce difference in the condition of gas expansion inside of a box due to heating temperature by using pressure inside of a pressure vacuum box. CONSTITUTION:An outer cylindrical bulb 1 having a round or lens-shaped head is mounted on a bulb holding jig 11 furnished with a large number of holes while setting a sealing bead fixed by a filament inside of the opening part of an outer cylindrical bulb 1 and arranging outside a heating carbon jig 5. While housing this inside of a pressure vacuum box 6 and vacuumizing the inside of the box, the carbon jig is electrically heated in order to promote gas generation while closing the vacuum bulb 16 when the vacuum degree is followed by leading-in sealing gas in order to obtain the prescribed gas pressure. Next, a flow of current in the carbon jig 5 is gradually intensified in order to seal with raised temperature while making not to produce difference between the gas pressure inside of the box and the gas pressure inside of the bulb and after finishing the sealing, the current flow is stopped to finish heating. |
