| 摘要 |
PURPOSE:To dissolve the over-correction of the coma error in the vertical direction near the middle section of the vertical axis by providing sub-coils on the neck side of a deflecting yoke to function in the direction to decrease the coma error and applying the super-linear characteristic to this function with the action of a pair of diodes. CONSTITUTION:Upper and lower sub-coils 2a, 2b generate the pin cushion magnetic field in the same direction as the main deflecting coil magnetic field and perform the positive correction in the same direction as the coma error correction in the vertical direction of a field controller. A pair of diodes 4 in reverse parallel are connected in series to the sub-coils 2, and a resistor 5 is connected in parallel with them. The coma error correction in the vertical direction by the sub-coils 2 is made super-linear. When this is combined with the coma error correction in the vertical direction by the field controller, the over-correction of the coma error near the middle section of the vertical axis on a screen can be prevented.
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