GB453496A - Improvements in cathode ray tubes, for use, for example, in television - Google Patents

Abstract

453,496. Cathode-ray tubes. GENERAL ELECTRIC CO., Ltd., Magnet House, Kingsway, London, and SEAGER, G. W., c /o General Electric Co., Ltd., Wembley, Middlesex. March 11, 1935, No. 7536. [Class 39 (i)] All electrodes requiring alignment are mounted rigidly on insulating members, such as steatite or mica plates 3..6, aligned by metal rods or tubes 8, 81 extending along the length of the tube and each passing through closely fitting holes or sleeves in or attached to the plates 3 .. 6. The plates are located along the rods 8, 8<1> at least in part by spacing sleeves 9 . . 12. As shown, the electron gun 23 is carried by a cylinder 22 fitting into or over a sleeve 21 carried by the accelerator electrode 17 itself supported by the two plates 3, 4. A more positive accelerator 18 and deflecting plates 19 are carried by the plate 5, and the second deflecting plates 20 are carried by the plate 6. The deflecting plates are secured to the plates 5, 6 by eyelets which may also hold spring fingers 29 bearing against the envelope to centre the assembly. An insulating plate 2 at the end of the assembly is held against the re-entrant end 14 of the envelope by leads 15 passing through an annular seal 16. The tubes 8, 8<1> may serve as or contain electrode leads. The tube is evacuated through an extension 25. To repair the tube by replacing the cathode structure 22, 23, the glass is cracked at 24 and the electrode assembly is removed, a new seal 16 being finally made. One or more of the pinches 31 described in Specification 378,994 may be provided. The deflecting plates nearer the screen may permit a less maximum deflection than the other plates. A guard ring at fixed potential may be mounted between the two pairs of deflecting plates or between the plates and the screen. Electrodes may be divided into groups, each group containing electrodes of similar potential being mounted on one insulating member. Leads 15 to electrodes at greatly differing potentials are on opposite sides of the pinch 16. Sheaths round the leads and shields over the insulating members prevent short-circuits due to loose fluorescent powder. Specifications 420,538, 435,690, 437,594, and 437,624 also are referred to.