| 摘要 |
PURPOSE:To provide an image with good convergence characteristic by forming a barrel type magnetic field as a whole using two sets of deflection coils, forming a barrel mag. field by one of these sets of deflection coils, and by forming a pin cushion mag. field by the other set of deflection coils. CONSTITUTION:A horizontal deflection coil is formed from a saddle type coil, while a vertical deflection coil is composed of a trocoidal coil 15 and saddle type coil 16, wherein the trocoidal coil generates a pin cushion mag. field while saddle type coil produces barrel mag. field. When deflecting in the central part of the screen, the current flowing through the saddle type vertical deflection coil 16 is greater than the current flowing through the trocoidal vertical deflection coil 15, and positive cross pattern is corrected. When deflecting in the perimeter of the screen, the current flows oppositely situated, and negative cross pattern is corrected. This accomplishes good convergence characteristic over the whole screen. |
