GB521638A - Improvements in or relating to the deflection of cathode-ray beams - Google Patents

Abstract

521,638. Television ; cathode-ray tubes. RADIOAKT.-GES. D.S. LOEWE. Oct. 17, 1938, No. 29980. Convention date, Oct. 20, 1937. Addition to 423,427. [Classes 39 (i) and 40 (iii)] Relates to scanning systems of the kind desscribed in the parent Specification and Specifications 456,717 and 521,637 in which, in order to improve the marginal sharpness of the image, push-pull potentials are applied to the deflecting plates together with a fluctuating positive bias, which increases with the deflecting voltage and is impressed on the plates in parallel and also on the electron lens electrodes. According to the present invention, a common transformer 8 with two secondary windings 9, 9<SP>1</SP> is used for deriving from the saw-tooth deflecting voltage 1, the fluctuating bias which is applied to the electron lens 7 and, over resistance 6, to the deflecting plates 4, 4<SP>1</SP>. The primary of the transformer is shunted by a resistance 10, and the secondaries are connected to condensers 11, 11<SP>1</SP>, this arrangement producing a voltage which increases with the square of the deflecting voltage by integrating the saw-tooth voltage. The condensers 11, 111 are preferably unequal in size. The Specification as open to inspection under Sect. 91 also describes (1) a system with pushpull deflecting voltages in which a magnetic lens is used, the saw-tooth voltages being applied by a triode to the lens coil without integrating, Fig. 3 (not shown) ; (2) a system in which the rapid line deflection is effected electrically and the slow field deflection magnetically. The magnetic iron deflecting plates are made in two parts insulated from each other, the parts 4a, 4a<SP>1</SP>, Fig. 4 (Cancelled), being connected to the anode, and the parts 4b, 4b<SP>1</SP> to the deflecting potential. This subjectmatter does not appear in the Specification as accepted.