GB501179A - Cathode ray device - Google Patents

Abstract

501,179. Cathode ray tubes. STANDARD TELEPHONES & CABLES, Ltd. March 4, 1938, No. 6851. Convention date, May 29, 1937. [Class 39 (i)] In a cathode-ray device comprising means for causing a beam of electrons to trace a continuous path over one side of a target so as to lay dowii electrostatic charges on successive portions thereof, and means for causing a second beam to trace a continuous path over the other side of the target so as to remove successively the charges laid down a predetermined time interval before by the first beam, the target comprises a plate of insulating material which is pierced by a number of conductive elements or electrodes passing from one side of the plate to the other, and these elements are associated with a common conductor or counter electrode, insulated from the elements so as to form'a number of condensers. The cathode-ray tube is divided into compartments 11, 12 by a target 13 comprising an insulating plate, through which are inserted plugs 46 of nickel or other conducting metal, arranged in a circle and which may be coated on the side 11 with carbon or on the side 12 with alkaline earth oxide. A ring 45 surrounds the target. In the tube 11 a cathode ray is produced by a heated cathode 18 and modulated by an element 34, in the input circuit of which are a resistance 25 and biassing battery 26, and condenser 23. The accelerating and focusing electrodes, 15, 16, and 17 are successively at higher potentials and a further potential difference is maintained between the lining electrode 17 and the ring 45. In the tube 12 the arrangements are the same except that a collecting electrode 60 is biassed positively with respect to the ring 45. In series with the electrode 60 is a resistance 38, across which is connected the primary of an output transformer connected to the first stage of an output amplifier. The deflecting plates 58, 59 and 51, 52 for the input and output cathode rays respectively, are connected across capacities and resistances 57, 56 and 53, 54 respectively, and these are supplied with a sinusoidal current so that the two cathode rays traverse a circular or elliptical path. A settable phase shifter 55 permits the phase difference between the sweeps of the two rays to be altered up to 360‹. Charges corresponding to the modulated input current are laid down on the elements 46 by the input ray, and are successively discharged to the electrode 60 by the secondary emission excited by the output ray. The elements may be arranged in an elliptical formation, or in rows in the meshes of a conducting grid which is embedded in insulator, the deflecting potentials being correspondingly altered.