| 摘要 |
PURPOSE:To prevent the deterioration of a picture by making a transmission light and a slit of other electrode provided on the way of passing of an electron beam corresponding to one or both of a prescribed vertical position and a prescribed horizontal deflection position to attain the correction of a deflection data. CONSTITUTION:Oblique slits SB, ST are provided to both ends of an effective screen of a vertical focus electrode 3', that is, a position at the outside to the right and left of the passing region of the electron beam reaching the screen. Electrodes BL, BU, TL, TU catching the electron beam are provided corresponding to the slits SB, ST at the screen side of the slits SB, ST, grounded by common resistors RL, RU so as to detect the flowing electron beam. The potential generated at the resistors RL, RU is compared, the result discriminating the level of both the potentials is inputted to a CPU to increase/decrease a vertical data memory 27 and the scanning line is controlled to be a prescribed position to be present substantially. |
