INTERNAL MAGNETIC SHIELD AND CATHODE-RAY TUBE

PROBLEM TO BE SOLVED: To prevent landing mistakes of the electron beams caused by the tube axis magnetic field by reducing a magnetic field By, that is emitted to the tube axis side from the edge of the long sides side frame, where an internal magnetic shield is installed. SOLUTION: In the internal magnetic shield 100 for the cathode-ray tube, that is formed by joining a pair of long sides side plates 101a, 101b of a nearly trapezoidal form arranged facing opposite to each other and a pair of short sides side plates 102a, 102b of a nearly trapezoidal form arranged opposed to each other forming a part of a nearly quardrangular pyramid face, slits 111, 112 are formed along the lower side bottom side of the long sides side plate. The slits 111, 112 function as magnetic resistance with respect to the tube magnetic field, which passes in the internal magnetic shield, and reduce generation of magnetic field By. As a result, landing mistakes due to the tube axis magnetic field is suppressed and occurrence of color slippage is prevented.