| 摘要 |
PURPOSE:To obtain a color picture tube of good vacuum degree, with an efficient gas blacking furnace used where the automatization of process before and after can be easily performed, by changing the blacking temperature from 500 to 570 deg.C. CONSTITUTION:In the method of blacking a support frame of the shadow mask, with a blacking temperature set to 500 to 570 deg.C, by using a continuous gas blacking furnace of mesh belt type to make a heating in the atmosphere of DX gas efficient with the automatization of process before and after easily performed, can be obtained a black film layer of two-layer construction of Fe2O3, Fe3O4. In this way, the vacuum degree, as shown by a curve B in the drawing, equally as good as that made blacking in the atmosphere of H2O, can be obtained. And, for instance, before the blacking of gas, a prior treatment in a range of temperature 300 to 600 deg.C within a shadowed portion, as shown in the drawing, in the atmosphere of H2O, then to perform the gas blacking at 600 deg.C can provide also a black film layer of good vacuum degree. |
