| 摘要 |
PURPOSE: A glass funnel and a process for its production are provided to obtain a tempered portion colored by local tempering and coloration of the glass funnel at the same time using a chemical method. CONSTITUTION: A glass funnel(1) for a cathode ray tube comprises a substantially rectangular opened end(5) at one end and a neck portion(4) at the other end and which constitutes, a glass panel having a substantially rectangular face portion, and a glass bulb to be used for the cathode ray tube. The glass constituting the glass funnel contains, by molar percentage, at least 60% of SiO2 and at least 7% of PbO, when the molar percentages of Na2O and K2O contained in the glass are represented by WNa and WK, respectively, 0.35<=WK/(WNa+WK)<=0.6. A compressive stress layer is formed by chemical tempering at least in the outer surface of a region(6) containing a position where the tensile stress formed when the interior of the glass bulb is vacuumed to produce the cathode ray tube, becomes maximum. Either one or both of the outer surface of the chemically tempered region and the inner surface opposite to the outer surface are colored by ion exchange coloration.
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