GB500090A - Improvements in electric discharge tubes and circuit arrangements incorporating such tubes - Google Patents

Abstract

500,090. Discharge apparatus; electron beam valves and circuits therefor. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. May 11, 1938, No. 14041. Convention date, May 14, 1937. [Classes 39 (i) and 40 (v)] In a discharge tube, such as a mixer tube for superheterodynes, employing double control over an electron system, the electrons from an indirectly-heated cathode 17, Fig. 3, pass through a control grid 18 and a screen grid. 19 and are formed by electrodes 21, at cathode or negative potential, into beams which pass along curved paths 22 to other electrodes collecting primary or secondary electrons, all the electrodes being surrounded by a control electrode 30 of solid material; the first control is exerted by control grid 18 adjacent the cathode and the second control by electrode 30 acting in a part of the discharge space from which electrons cannot substantially return to the first control electrode, the paths over which the electrons are affected by the second control electrode being considerably longer than the paths over which they are affected by the first control electrode. The electrodes 21 may bo replaced by solid portions of the control grid, which may be entirely of rods. The beam may be deflected to strike one or the other of the two electrodes 25, 29; the output circuit may be connected between these electrodes or to one of them. Alternatively the electrode 25 may be coated with secondaryelectron-emissive material and provided with apertures 26, behind which is a positive collector electrode 27. The deflected electron beam either strikes the electrode 25, dislodging secondary electrons which pass to anode, 29, or passes through apertures 26 to electrode 27. In a modification, the electrode 27, Fig. 3, is kept at cathode or negative potential so that electrons passing through the apertures 26 are driven back to the electrode 25. In this case the valve may be used as a self-oscillator, as shown in Fig. 6, in which the control electrode 30 and the electrode 25 form the oscillator section, the output circuit being connected to electrode 29. Magnetic or electrostatic fields may be employed to assist the second control electrode to deflect the electrons into curved paths. The Specification as open to inspection under Sect. 91 includes also a modification, Fig. 4 (Cancelled), in which four beams issue from the cathode and pass to two gauze electrodes 29 behind which are secondary-emissive electrodes 25. The beams either pass through the apertures in anode 29 to the electrode 25, from which secondary-electrons are returned, or strike the support rods 27 of the anode 29. The focusing electrodes 21 are, in this case, outside the screen grid. This 'subject-matter does not appear in the Specification as accepted.