DEFLECTING UNIT PROVIDED WITH RING-SHAPED SUPPORT BODY FOR FIELD-CORRECTION ELEMENT AND CATHODE-RAY TUBE PROVIDED WITH SAID DEFLECTING UNIT

摘要

PURPOSE: To provide an electromagnetic deflection unit for a cathode-ray tube equipped with a field correction element capable of improving image quality over the entirety of a screen. CONSTITUTION: This electromagnetic deflection unit includes a coil holder having a flange. (Line) deflection coils for electron beam deflection are supported in the inside of the holder. A (magnetized) prefabricated correction element 14 on the flange side of the coil holder is arranged inside of the coils to exert an influence upon magnetic field generated by these coils. This can reduce errors of variations occurring in manufacturing over the entirety of a display screen. An annular support 13 having a prescribed accommodating position 12 is employed so that the correction element 14 can be automatically attached. The correction elements 14 are attached to a plurality of supports 13 in the accommodating position 12. If the correction element 14 is made of permanent magnetic material, the magnetic field having a strength of l to 1000μT is generated at a position separated by a few millimeter from the center of the element 14.