GB521637A - Improvements in the deflection of cathode-ray beams - Google Patents

Abstract

521,637. Television ; cathode-ray tubes. RADIOAKT.-GES. D. S. LOEWE. April 25, 1938, No. 12314. Convention date, April 26, 1937. Addition to 423,427.' [Classes 39 (i) and 40 (iii)] Relates to systems in which the deflecting plates are energized in opposite phase, as in the parent Specification. To secure a sharp focus of the cathode ray, even on wide deflection, the deflecting plates 1, 2 have an instantaneous average potential which increases with the instantaneous value of the deflecting voltage. The plate which is relatively negative is connected to the anode 3. The average potential of each deflecting plate is positive relatively to the anode by about half the value of the deflecting voltage. A bias, varying up to this amount, is obtained by integrating the deflecting voltage 23, Fig. 6, by charging a condenser 14 through a resistance 34. The voltage to be integrated is obtained from the secondary of a transformer 12, the primary of which is in series with the primary of the transformer 8 and a pentode 15 controlled by the relaxation oscillator. The electron lens 26 is also corrected simultaneously by the correcting voltage so that the focal length of the lens is increased with increasing deflection of the ray. Specification 456,717 also is referred to. The Specification as open to inspection under Sect. 91 also describes circuits in which the deflecting voltages 23, Fig. 3 (Cancelled), are applied through a transformer 8 with a centretapped secondary and each plate is connected to the anode by a rectifier 10a, 10b which conducts during the negative half cycle. Alternatively, the deflecting voltage from a relaxation oscillator is applied to each plate by a Class-B amplifier, Fig.. 4 (not shown). This subject-matter does not appear in the Specification as accepted.