| 摘要 |
PURPOSE:To correct the raster distortion by partially emphasizing the barrel form of a horizontal deflection magnetic field by providing each of magnetic pieces installed facing the upper and the lower inner surfaces of a vertical deflection coil with a convex area protruding toward the central axis of a deflection york. CONSTITUTION:Magnetic pieces 6 are installed facing the inner surfaces of an upper and a lower vertical deflection coil 3. The central area of each magnetic piece 6 corresponding to an area free of a horizontal deflection coil 2 is provided with a convex area 18 protruding toward the central axis of a deflection york. Owing to the effect of convex areas 18, the barrel shape of a horizontal deflection magnetic field is emphasized and vertical deflection force 17 also works during the horizontal deflection of electron beams 11. Accordingly, as compared to the time when the magnetic pieces 6 have no convexes, pin-cushion distortion increases by a degree corresponding to the lateral raster. Therefore, by either achieving a field shape having an intensified pin-cushion form on the picture screen side of a horizontal deflection coil 3 or by installing permanent magnets at the right and the left ends of the picture screen side of the deflection york, the pin-cushion distortion and the barrel distortion can be canceled each other and the raster distortion can be eliminated. |
