| 摘要 |
PURPOSE:To blacken extremely simply an explosion-proof band of an explosion- proof cathode-ray tube to be incorporated into a push-through type picture tube. CONSTITUTION:A holding metal fitting member is treated to be blackened in order to make it into the almost L-shaped holding metal fittings having punched hole parts. Said blackening treatment is performed by black chromating treatment of zinc-plated soft steel as a holding metal fitting member or by applying black coating varnish. Also a long metal band is cut into the fixed length and both ends are joined by welding points 28a at a junction part 28 to be made into a ring metal band whereby a thermally blackening material, for instance, zinc- plated iron for thermal blackening is used as said ring metal band 26. Further the holding metal fittings 25 and the ring metal band 26 are fixed by welding at the welding points 25a in order to finish an explosion-proof band 27. A high frequency coil 31 is provided inside of said explosion-proof band 27 to be heated up to about 500 deg.C and immediately after thermally blackening the surface of the ring metal band 26, a cathode-ray tube is inserted while shrink-fitting into the side wall part of a face plate of said cathode-ray tube in order to finish an explosion-proof cathode-ray tube. |
