GB604249A - An improved cathode-ray tube device for generating ultra high-frequency oscillations - Google Patents

Abstract

604,249. Cathode-ray tubes. PHILIPS LAMPS, Ltd. Nov. 24, 1945, No. 31766. Convention date, July 11, 1940. [Class 39 (i)] For generating ultra-high-frequency oscillations, a concentrated beam of electrons moving at a uniform velocity is deflected by changes in a transverse field and travels towards a plurality of electrodes, relatively spaced in the direction of movement of the electrons, the first electrode being apertured to pass the beam intermittently to impinge on the last electrode, two of the electrodes being united to form a hollow resonator tuned to the frequency of the oscillations set up by the intermittent flow of electrons through it. In one form a beam of electrons generated by cathode 1, Fig. 1, modulator 3, anode 5, focusing coil 7 and magnetic screen 8 is deflected by plates 9 in a plane so that it passes over opposite parts of an annular gap 25 in an electrode 17 which forms a resonator with collecting electrode 19 and annular box 23. The beam enters the resonator four times in one cycle of deflection and thus excites it at the frequency of four times the deflection frequency. The oscillation is conveyed to a dipole 35 by coaxial line 31, 33. A grid 27 midway between electrodes 17, 19 dynamically connected by condensers to earth and to a nodal point of the resonator suppresses secondary emission from electrode 19, which is coated with soot to reduce such emission. In a modification, the electron beam is ribbon-shaped. In another form, the beam is rotated in circle by pairs of plates 9, 10, Fig. 6, fed in quadrature, and strikes a number of apertures 26 arranged in a circle on electrode 17. In this case electrodes 17, 19 do not form the resonator which is formed by two intermediate apertured plates 47, 49. The nodal point of the resonator 51 thus formed is raised to a much higher potential than electrodes 17, 19 so as to reduce the electron transit time through them, which should not exceed one half cycle of the generated oscillation. The subject-matter of this Specification is identical with that of Specification 555,790.