| 摘要 |
PURPOSE:To obtain an image with a very good contrast and high clearness having almost no faded or blurred light spot consisting the image by providing illuminants such as phosphor, and the like on one side of an image transmission face plate corresponding to each lens part in a cathode-ray tube face plate. CONSTITUTION:A masked substrate 10 is floated in liquid salt 13 containing ions of thallium (Tl) and cesium (Cs) largely contributing to increase a refractive index while keeping a lens formative face downward and the upper side (a light absorbing layer formative face) thereof is surrounded liquidtight by side plates 14 while the inside thereof is filled with salt 15 containing glass colored ions such as Ag, Cu and Au ions, for instance, silver sulfate liquid salt. In this way, lens parts with crescent sections having refractive index distribution corresponding to the distribution of thallium ion concentration are formedon a glass face on the anode side. Further at the same time, Ag ions are doped to substrate glass at the part not covered by the mask 12 on the other surface of the substrate 10. Thereby the sectional shape 4A of the lens parts becomes nearly semicircular thus improving the refractive index distribution thereof. |
