Patent GB-500005-A (GB)
Title: Multi-cathode ray discharge device
IPC: H01J29/50
Filed: 1938-02-18
Abstract: 500,005. Cathode-ray tubes. STANDARD TELEPHONES & CABLES, Ltd. Feb. 18, 1938, No. 5172. Convention date, May 29, 1937. [Class 39 (i)] In cathode-ray tubes with several rays in one tube, as for multiple scanning in television or for reproducing different phases of electrical phenomena, parallel electron gun units are consolidated into a rigid unitary structure supported at one end of the tube from a stem and provided with a common accelerating electrode. The tube, which maybe provided with a fluorescent screen and used with a photographic film for making permanent records, comprises a glass vessel provided with a tubular extension 13, Fig. 2, having a re-entrant stem 16 and an inner tubular wall 17 Three parallel gun units 19.. 21 are provided, each comprising a platform 22 on which is mounted a cylindrical indirectly-heated cathode 23, Fig. 6, surounded by a cylindrical modulating electrode 24 and a tubular anode 25 having an internal collimating element 26 and fitting over an abutment 27 on the platform 22. The gun units are united by transverse connecting members 32, having flanged portions 33 through which pass rods 35 attached to collars 36, 37 embracing the stem 16. Leads for the application of suitable potentials to the gun units pass from a cap at the end of the tube through the press 40, the anode potential lead being connected to one of the rods 35. The end of the tube 17 is closed by a disc 51 having apertures 52 coincident with the openings of the gun units, this disc being secured to a metallic sleeve 53 which is sealed to the glass by a knife edge seal 54. The disc 51 serves as an accelerating electrode and the electron beams are shielded from the sleeve 53 by an apertured metallic block 55; alternatively the anode tubes may be extended up to the disc 51. To support the three sets of beam deflecting plates an apertured insulating platform 56 is provided which is supported from the disc 51 by posts 57. The time-sweep plates are arranged above the platform and the others are suspended below it; The upper outer plates such as 69 fit in slots in the platform and are provided with extensions 74 which pass through slots in the platform and are bent over on the opposite side. The. middle upper plates 80, 81 and shields 84, 85 between the plate pairs also fit in slots in the platform, the shields being provided with bent-over extensions similar to the extensions 74, and all the upper plates and shields being united together by locking bars 78, 79 which are grooved to engage recesses in the shields and fit in channel members 76 attached to the plates. The lower plates such as 58 are supported from the platform by fitting into slots therein, extensions 60 on the plates passing through the platform and being bent over on the far side. Each of the twelve deflector plates is provided with a lead, brought out through the tube wall 13, these leads being connected to terminals arranged circularly. round a base which is fixed round the tube immediately below the part F. To this base is also brought out a lead which is connected to a post 57 and which serves by means of springs 96, 97 engaging the graphite coating on the wall of the vessel and by means of strips 94, 95 connected to the shields 84, 85, to apply earth potential to these parts.