GB431327A - Improvements in or relating to discharge devices such as cathode ray tubes - Google Patents

Abstract

431,327. Cathode-ray tubes. ELECTRIC & MUSICAL INDUSTRIES, Ltd., Blyth Road, Hayes, Middlesex, CONDLIFFE, G. E., Thorncombe, Fulmer Road, Gerrards Cross, Buckinghamshire, SHOENBERG, I., 203, Willesden Lane, and TEDHAM, W. F., 267, Woolwich Road, Abbey Wood, both in London. Oct. 3, 1933, Nos. 27199/33 and 20960/34. [Class 39 (i)] In a cathode-ray tube arrangement of the hard type having a cathode, a first accelerating electrode, a decelerating electrode with an apertured diaphragm, and a second accelerating electrode so arranged that the ray passes through them to a screen and is focused by electrostatic or electromagnetic means, a potential equal or nearly equal to that of the cathode is applied to the decelerating electrode, and positive potentials to the accelerating electrodes, these potentials and the shape and disposition of the electrodes being such that increases of potential of the decelerating electrode in a negative sense produce increases of current to the first accelerating electrode. As shown, the first accelerator 7, the decelerator 8, and the second accelerator 9 are mounted with an apertured shield 6 for an indirectlyheated cathode 5 on a glass tube 4 extending from the foot. The decelerator 8 consists of a cylinder with an apertured disc mounted about half way along it, and the accelerators 7, 9 consist each of a cylinder with an apertured disc at one end. A second apertured disc 23 may be arranged inside the accelerator 9. An anode 15 overlaps the accelerator 9. Dimensions and values of the potentials are given. For example, the accelerator 7 may be at 200 volts positive, the decelerator 8 at 20 volts negative, the accelerator 9 at 1000 volts positive, and the anode 15 at 3600 volts positive with respect to the cathode ; or the accelerators may be at the same potential. Modulating potentials may be applied to the decelerator. The shield 6 may be omitted. The ray is focused to a spot on the screen by the electrodes 9, 15, or a magnetic electron lens may be used. In another arrangement three accelerators and two decelerators are provided so as to produce two deceleration regions ; a third deceleration region may be produced by two additional electrodes.