METHOD FOR MANUFACTURING FUNNEL OF MICRO CATHODE RAY TUBE

PURPOSE:To provide a simple method for manufacturing the funnel portion of a micro cathode ray tube, by inserting a glass plate material between a male mold provided with an pyramidal pressing bulge and descending by its dead load and a femal mold provided with a pyramidal depression and by heating them. CONSTITUTION:A micro male mold 3 and a micro female mold 5 made from a carbon meterial are adapted such that a pyramidal space is formed between a pyramidal depression 15 in the female mold 5 and a pyramidal pressing bulge 11 on the male mold 3 descending by its dead load toward the femal mold and the thickness of the pyramidal space becomes gradually smaller as the male mold 3 descends. The male mold 3 and the female mold 5 with a plate glass material 'a' inserted therebetween are put in a heating furnace in a nitrogen atmosphere and the same is heated up to 980 deg.C-1,050 deg.C so that the plate glass materiall 'a' is melted and fills the space. In this way, a thin walled funnel for a micro cathode ray tube can be formed smoothly.