| 摘要 |
PURPOSE:To manufacture an excellent electron tube by enabling foreign substances to be almost completely removed from the said tube by performing both a tapping carried out in an vacuum and a tapping carried out in a leak. CONSTITUTION:A plural number of stem-seal-completed bulbs 23, each of which is assembled by fitting only an electron gun structure inside an outer tube 1 without sealing a face plate 12 of an image pickup tube, are set by fixing their exhaust pipes 18 to the peripheral part of a base plate 22. Next, a manifold 21 and a bell jar 20 are evacuated by driving a diffusion pump 24 and a rotary pump 25. At the same time, the bulbs 23 are heated to a high temperature by heating the inside of the bell jar 20 to a given temperature by means of a high-frequency coil 30, and a shaft 32 is rotated in the direction indicated by the arrow by driving a tapping-rotation motor 33. As the result, foreign substances adhering to the inner walls of the bulbs 23 and to the electron gun structures fitted inside the bulbs 23 are dropped onto the inner bottom of the bell jar 20 and removed. |
