| 摘要 |
PURPOSE:To cancel the trapezoidal distortion on a screen by forming the vertical deflection coil of a deflection yoke with two pairs of coil unit while making the number of turn of them different thereby providing the trapezoidal distortion on the raster on the phosphor face. CONSTITUTION:The horizontal deflection coil 9 in the deflection yoke 8R of a projection tube is sadle type while the vertical deflection coil 10 wound around the core 11 is troidal type. The vertical deflection coil 10 is divided into coil units 10a, 10d, and 10b, 10c and the winding angles alpha1, alpha2 or the number of the windings n1, n2 are made different then wound symmetrically against the center line 13. Consequently the vertical deflection of the electron beam is made different at the left and the right of the center line 13 to produce the raster formed on the phosphor face of the projection tube 8R such as that shown by the dashed line 14 having the trapezoidal distortion, thereby the trapezoidal distortion to be produced when projected on the screen can be cancelled resulting in a good rectangular raster. |
