| 摘要 |
A method of manufacturing a color television display tube, the envelope of which comprises a conical portion (11) and a window portion (12) which are sealed together in a vacuum-tight manner by means of a sealing glass (18). Before these portions are sealed together, a gettering device (21) is positioned inside the envelope of the tube, for example by attachment to the internal magnetic screening cap (17) or to the high-voltage contact (26). The gettering device (21) comprises a source of evaporable gettering metal and a material releasing gas upon heating. The gas-releasing material (5) is protected from the influence of moist air at comparatively high temperatures by means of a layer of metal (6) provided on the grains of the material (5). As a result of this the gettering device (21) is suitable for being assembled in a television display tube before the window (12) and the cone (11) of the tube have been sealed together by means of a sealing glass (18).
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