| 摘要 |
The aperture mask of a color cathode-ray tube is formed of a blank of annealed steel which has a multiplicity of apertures disposed in a rectangular field. The opposed surfaces of the blank have etchant resistant oxide layers and the walls of the apertures are lined with a flash coating of a material which is resistant to oxidation but is subject to attach by the same etchant that attacks the material of the blank. The apertured blank is used for photographic printing of the screen of the color tube after which it is subject to an etch bath which first removes the liner and then, by attacking the walls of the apertures, enlarges them to a size exceeding the phosphor deposits of the screen. With the apertures enlarged, and with the oxide layers retained, the mask is installed in operative position relative to the screen.
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