| 摘要 |
427,090. Cathode-ray tubes. HUDEC, E., 17, Potsdamerstrasse, S³dende, Berlin. July 13, 1933, No. 19781. Convention date, July 13, 1932. [Class 39 (i)] In Braun tubes operating with a single ray of electrons, one pair of plates for deflecting the ray to scan the screen is so formed that the deflecting field is much stronger at all points near one plate than near the other. The plates P1, P<1>1, Fig. 2, may be cylindrically curved to give the non-uniform field shown. The plate P1 is connected to the anode A and the undeflected ray is nearer the negative plate P<1>1. As the deflection increases, the deflecting field decreases to compensate for the decrease in the speed of the electrons and so to keep the deflection proportional to the deflecting voltage. In modifications, flat plates of different length or width are used or one plate may be divided to form a main part d, Fig. 4, and small parts b, b<1> at one or each end or side of the part d, the parts b, b<1> being connected to the opposite plate P or to a fixed potential. The part b may shield the other pair of deflecting plates from the variable field of the plate d to avoid trapezoidal distortion of the image. Instead of maintaining the ratio of deflection to deflecting voltage constant, the usual increase in the ratio with increasing voltage may be exaggerated, for example, if the potential does not increase linearly with time. Specification 380,381 is referred to. |
