| 摘要 |
<p>1451211 Colour television tubes RCA CORPORATION 2 Oct 1973 [18 Oct 1972] 45925/73 Heading H1D An optical lens for use in the manufacture of the phosphor screen of a colour television tube has a first effective surface divided by boundaries of surface discontinuity into a plurality of elements, each of which is separately contoured to reduce misregister in the finished phosphor screen, and a second effective surface similarly divided and surface contoured to additionally reduce misregister. The first surface may be divided into parallel strips, Fig. 1, or sectors (Fig. 13, not shown) the second surface being divided into parallel strips, oriented perpendicular to the strips on the first face, if present, Figs. 1 and 2, or into annuli, (Fig. 12, not shown). The lens may be constructed from a single piece of glass or plastics material, or from a plurality of individual parts, e.g. strips, rings, or sectors Reference is made to the possibility of forming the two surfaces one on each of two discs, which are thereafter bonded together, or may be spaced apart.</p> |
