| 摘要 |
PURPOSE:To simplify the investigation of cracks and the like in the fused portion of a wafer portion where a plurality of welds are annularly planted passing through the wafer, and an exhaust tube fused to the opening in the wafer by forming the wafer and the exhaust tube with the glass of the same composition and different colors. CONSTITUTION:A cathode ray tube stem 15 is formed of a wafer portion 12 annularly planted with a plurality of welds passing through the wafer 12 and an exhaust tube 13, an end of which is fused to the periphery of an opening 121 provided in the center portion of the wafer 12. The wafer portion 12 and the exhaust tube 13 are made of a glass having the same composition and the wafer portion 12 is colorless and the exhaust tube 13 is blue to be different in the color. Such construction facilitates to nondestructively investigate the presence of cracks and the joint strength from the shade of the color obtained by photographing the fused portion 14 by means of such as a color distinguishing camera and to improve the work efficiency. |
