EARTH MAGNETISM CORRECTION DEVICE OF CATHODE RAY TUBE AND CATHODE RAY TUBE WITH CORRECTED EARTH MAGNETISM

摘要

PROBLEM TO BE SOLVED: To prevent purity of a luminescent light on a screen from being deteriorated, which results from mis-landing of an electron beam on the screen, whose orbit is affected by a magnetic field from an increase in an induction current flowing to a coil of an earth magnetism correction device of a cathode ray tube caused by interlinking with a magnetic field leaked from a deflection yoke. SOLUTION: Excitation of self-resonance of a loop coil 2 being a component of the earth magnetism correction device due to a magnetic field leaked from a deflection yoke is prevented. For this purpose, a damping resistance 3 is provided to the loop coil so as to reduce an inductive component of an impedance of the loop coil at self-resonance. Furthermore, a capacitor is added to the loop coil to bring a self-resonance frequency due to the inductance of the loop coil to a lower frequency sufficiently from a deflection current frequency.