| 摘要 |
PURPOSE:To obtain an image-pickup tube in which a proper distance is maintained between a negative electrode and the first electrode even if the opening of the first electrode is small and which is equipped with the electron gun whose negative electrode and the first electroe are connected to each other. CONSTITUTION:After inserted into a cylindrical spacer 10, a negative electrode structure is further inserted in it until the top part of the spacer 10 makes contact with the first dummy electrode 11 which is equipped with a sufficiently large opening 11a electrically insulated and which is connected to the second electrode 12 by a means not shown in the figure. The first dummy electrode 11 and the spacer 10 are grounded in this state, and the distance between the second dummy electrode 12 and the negative electrode 1 is set to obtain a proper electrostatic capacity through the capacitance method or the air-micro method, by taking in and out the abovementioned negative electrode structures 1-5 into the spacer 10, and then the spacer 10 and a ceramic holder 4 are fixed. Then, the negative electrode structures 1-5 are taken-out from the first dummy electrode 11, and inserted in the first electrode 6 until the spacer 10 makes contact with its ceiling and then the first electrode 6 and the spacer 10, or the ceramic holder 4 are fixed together. |
