METHOD OF MANUFACTURING A COLOUR TELEVISION DISPLAY TUBE HAVING A GAS-ABSORBING LAYER; COLOUR TELEVISION DISPLAY TUBE THUS MANUFACTURED, AND GETTERING DEVICE SUITABLE FOR SUCH A METHOD

摘要

The invention relates to a method of manufacturing a colour 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 said portions are sealed together, a gettering device (21) is assembled in a place inside the envelope of the tube, for example to the internal magnetic screening cap (17) or the high-voltage contact (26). The gettering device (21) comprises a source of evaporable gettering metal and at least one 25 as source of a material releasing gas upon heating. The gas-releasing material (5) is protected from the influence of moist air at comparatively high temperature by means of a layer of metal (6) provided on the grains of the gas-releasing 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).