Patent GB-770047-A (GB)
Title: Improvements in or relating to electric circuits and discharge tubes for storing andtransmitting elements of information
IPC: G06F7/38
Filed: 1953-04-02
Abstract: 770,047. Electric digital data storage and calculating apparatus. PHILIPS ELECTRICAL INDUSTRIES, Ltd. April 2, 1953 [April 5, 1952], No. 9208/53. Class 106 (1). [Also in Group XL (a)] In a storage tube of the kind in which one or more electron beams impinge on secondary emission target electrodes, the secondaries being drawn off by a suction electrode, there are one or more controlling electrodes and one or more controlled electrodes the controlling electrodes at least partly surrounding the controlled electrodes, the controlling electrodes can be at cathode potential or at a more positive potential and on application of a positive pulse to the controlled electrodes while they are simultaneously being struck by the beam, the controlled electrodes which are secondary emissive in a ratio greater than unity go to cathode or to suction electrode potential according as to whether the controlling electrodes are at cathode potential or positive (the secondary emission from the controlled electrodes being suppressed if the controlling electrodes are at cathode potential) and a plurality of changes in the potential of the controlled electrodes can be effected without changing the beam direction. In the simplest case, Fig. 1A, if one or both control electrodes B, C are at zero potential the secondary emission electrode A is always driven to zero potential, while if B, C are both positive electrode A is always driven to collector potential. The control pulse may be rectangular, or may vary from Vg initially to 0.4Vg at the end (Vg is collector voltage) in which case it may be used as an erasing pulse to bring all electrodes to Vg (condition 1). There may be more than two electrodes B, C for each electrode A in which case Va=O or Vg depending on whether one or a few of the control electrodes are positive or whether all of them are positive. In one embodiment, Fig. 5, an insulating support carries secondary emission electrodes E 1 , E2 ... on one side and impulse electrodes 1, 2 on the other side. The electrodes E 1 , E 2  may be formed by vaporization through a templet or by vaporizing directly and removing the unwanted parts by scratching or etching, or by photographic methods, and may have parts of different secondary emissivities. The support is of mica or an oxide layer on a metal surface, and the secondary emissive material is coated on the vaporized layer. Parts liable to be struck by stray electrons may have a coating of material whose secondary emissivity is unity. The beam is swept over parts A, E is made equal to 0 or Vg by an external pulse (0 or 1 on the binary system) and this indication is transmitted along the row of electrodes by alternately pulsing electrodes 1, 2. The indication can be read off by further pulses to 1, 2 or brought back to the left by sweeping the beam over parts B while pulsing 1, 2 as before. For a number with more than one digit, E 1  is given successively the voltages corresponding to successive digits while the impulse electrodes 1, 2 are alternately given a pulse between the application of successive digits to E 1'  To record arbitrary indications it is necessary to provide erasing pulses between the control pulses. The erasing and control may be achieved by a single scanning beam or separate scanning beams. A separate flooding beam striking all the electrodes simultaneously holds them in condition 0 or 1. Alternatively the even electrodes may be simultaneously controlled by the odd electrodes and subsequently vice versa. In a modification, Fig. 6 (not shown), the secondary emission electrodes are  - |<SP>-</SP> -shape and strip control electrodes (corresponding to B, C, Fig. 1A) are provided on either side of the row of secondary emission electrodes. A number of strip-shaped impulse electrodes are used. The number of indications stored can be increased by connecting a number of rows of electrodes in parallel, Fig. 7 (not shown), deflecting plates being provided for deflecting the beam from one row to another, and such a tube can be used in decimal computers. In another form, Fig. 8, the secondary emission electrodes E are " forkshaped " as shown. The beam which is not deflected strikes parts A and C and impulses are supplied alternately to strip-shaped impulse electrodes 4, 41. To avoid collection of electrons by parts B, rods 6, Fig. 9, which preferably constitute a grid, at low or zero potential focus the electrons on to the centre of parts A. If parts A are in condition 0 (zero potential) the primary electrons are reflected to slotted plate collector 5 which replaces grid g of Fig. 1B (not shown), while for condition 1 (collector potential) secondaries are produced by primaries striking A and pass to electrode 5. In a double unit tube the cathode 9,- Fig. 11, is of rectangular cross-section and is surrounded by positive space charge grid 10, electrode 6 comprising two flat grids wound on screens 11, and two slotted collectors 5; two separate secondary emitting and impulse electrode structures 3 are also provided. The impulse electrodes of each unit are separately energized so that the units operate in parallel. The rows of secondary emission electrodes of each target may be connected in series so that the indications pass over from the end of one row to another row and the fork-shaped parts of electrodes of adjacent rows may point in opposite directions. In other embodiments, each secondary emission electrode can control or be controlled by a plurality of other electrodes, for example in a binary multiplication arrangement, Figs. 12-15 (not shown). An impulse travelling along a row of electrodes may be branched at given points. The secondary emission electrodes may control a further electron beam, e.g. by deflection, which can be used to give an optical or electrical indication of their voltage condition. Alternatively an optical indication can be obtained by coating the secondary emission electrodes with luminescent material.