JPS57208036A - High-voltage treatment of cathode-ray tube - Google Patents

Abstract

PURPOSE:To enable a high-quality cathode-ray tube with an excellent voltage- resisting characteristic to be obtained by subjecting the tube to high-voltage treatment by performing high-voltage ageing of the electrodes of an electron gun, without causing any spark flaw or goass separation of the inner wall of the neck of the tube. CONSTITUTION:A part of a focusing electrode group, a high-voltage-applied electrode group, which forms a main electron lens part is subjected to high- voltage treatment by developing compulsory discharge between the focusing electrodes by, for example, applying a high voltage of rectified half-waves across them, while applying a magnetic field across them by installing a cylinderical magnet onthe outer wall of the neck of a cathode-ray tube corresponding to the main electron lens forming part of the focusing electrode group. The spark flaw and the glass separation of the inner wall of the glass is widely reduced by applying a high voltage across the focusing electrodes 18, 19 ... forming the main electron lens part, while applying a magnetic field 22 extending along the axis (Z) of the tube across the electrodes 18, 19 ....