GB434111A - Method of and arrangement for producing image points of defined form in braun tubes - Google Patents

Abstract

434,111. Cathode-ray tubes. RADIOAKT.-GES. D. S. LOEWE, 10, Wiesenweg, Steglitz, and SCHLESINGER, K., 39, Friedrichstrasse, Friedrichshagen, both in Berlin. Dec. 18, 1933, No. 35510. Convention date, Dec. 20, 1932. [Class 39 (i)] . In a television tube in which a concentrated and modulated cathode - ray is deflected at right angles by two deflecting plate systems to cause it to scan the picture screen, the two plates of at least one of the systems are both biassed positively or negatively to the same extent with respect to the anode adjacent the systems, the bias being so great that a constant substantial deformation of the cross-section of the ray results. The biassed systems may also act to concentrate the ray. If both systems are biassed negatively, a ray of rectangular or square crosssection is obtained, the image point on the screen being of height h/Z where hand Z are the height of the picture and the number of lines therein. If three-plate deflecting systems as described in Specification 432,209 are used, .the two outer plates are biassed relatively to the anode. The centre plate is biassed positively relatively to the outer plates and has a wide slot to avoid changes in the crosssection of the ray at the slot. The bias voltages are obtained from potentiometers. The Specification as open to inspection under Sect. 91 comprises also the deformation of the cross-section of the ray by other transverse "attraction or pressure" fields. In one modification, the ray is passed between knife edges at the ends of biassed strips 31 .. 34, Fig. 1 (Cancelled), transverse to the ray. In other modifications, the cross-section is deformed by passing the ray through biassed slotted diaphragms. The central slotted diaphragm of the three-plate system described in Specification 432,209 may be used by making the slot narrow and of length at least equal to the width of the outer plates, or special diaphragms 26, 28, Fig. 5 (Cancelled), are connected respectively to the first anode and to the centre plate 9 of the deflecting system and are screened by large-aperture diaphragms 27, 29 connected to the second anode 6. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specification 423,427.