| 摘要 |
PURPOSE:To prevent any convergence shifts by stabilizing the electric potential of the inner surface of the neck and electric charges existing on the surface of a bead glass by providing two conductive films near a gap between electrodes which form a main electron lens in such a manner that said conductive films face each other. CONSTITUTION:The third to the fifth grids 23, 24 and 25 are used to form an auxiliary electron lens. The fifth and the sixth grids 25 and 26 are used to form a main electron lens. The auxiliary electron lens and the main electron lens are called a main electron lens system and focus an electron beam on the picture screen of a picture tube. On an area of the inner surface of the neck corresponding to the fifth grid 25, a neck conductive film 32 is formed which is extended to around an area of the inner surface of the neck corresponding to a gap between the fifth and the sixth grids 25 and 26. Facing the neck conductive film 32, a bead-glass conductive film 31 is formed on the surface of a bead glass 27 near the gap between the fifth and the sixth grids 25 and 26. The bead-glass conductive film 31 is electrically connected to a conductive lead wire 30, which is wound around the bead glass 27 and connected to the fifth grid 25, such as a stainless weire for example. |
