Method of installing a color selection electrode in a color cathode ray tube

In the manufacture of a color cathode ray tube of the type having a phosphor screen and spaced therefrom a tensed color selection electrode, a method of installing the electrode such that under normal tube operating conditions, the electrode is held by a holder in a hypertensed state and is thus capable of withstanding an unusually high electron beam bombardment before relaxing, said method comprising:

• forming the electrode from a material which has a significantly higher coefficient of thermal expansion than that of the holder;
• externally heating the electrode and the holder while tensing the electrode and simultaneously effecting selective auxiliary heating of the electrode such that the holder is heated to a predetermined first elevated temperature and the electrode is heated to a predetemined second elevated temperature significantly greater than said first temperature, said holder and electrode thus being caused to thermally expand, but said electrode by a greater amount;
• affixing the electrode to the holder;
• and
• cooling the electrode and holder to room temperature so as to hypertense the electrode due to the greater coefficient of thermal expansion and temperature fall of the electrode than the holder.

In the manufacture of a color cathode ray tube of the type having a phosphor screen and spaced therefrom a tensed color selection electrode, a method of installing the electrode such that under normal tube operating conditions, the electrode is held by a holder in a hypertensed state and is thus capable of withstanding an unusually high electron beam bombardment before relaxing, said method comprising:

• forming the electrode from a material which has a significantly higher coefficient of thermal expansion than that of the holder;
• externally heating the electrode and the holder while tensing the electrode and simultaneously passing an electrical current through it such that the holder is heated to a predetermined first elevated temperature and the electrode is heated to a predetermined second elevated temperature significantly greater than said first temperature, said holder and electrode thus being caused to thermally expand, but said electrode by a greater amount;
• affixing the electrode to the holder;
• and
• cooling the electrode and holder to room temperature so as to hypertense the electrode due to the greater coefficient of thermal expansion and temperature fall of the electrode than the holder.

In the manufacture of the color cathode ray tube of the type having a phosphor screen and spaced therefrom a tensed color selection electrode, a method of installing the electrode such that under normal tube operating conditions, the electrode is held by a holder in a hypertensed state and is thus capable of withstanding an unusually high electron beam bombardment before relaxing, said method comprising:

• forming the electrode from a material which has a coefficient of thermal expansion which is no less than that of the holder;
• externally heating the electrode and the holder while tensing the electrode and simultaneously effecting selective auxiliary heating of the electrode such that the holder is heated to a predetermined first elevated temperature and the electrode is heated to a predetermined second elevated temperature significantly greater than said first temperature, said holder and electrode thus being caused to thermally expand, but said electrode by a greater amount;
• affixing the electrode to the holder;
• and
• cooling the electrode and holder to room temperature so as to tense the electrode due at least to the greater temperature fall of the electrode than the holder.