US2591981A - Circuit arrangement, including a cathode-ray tube comprising cathode-ray beam deflecting means - Google Patents

Description

April 3, 1952 A. J. w. M. VAN OVERBEEK ETAL 2,591,981

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATl-IODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1947 7 Sheets-Sheet 1 A.J.W-M.VAN OVERBEEK,

Z-VANGELDER5\JJ H.JONKER INVENTORS aw Q .fl ff' AGENT April 1952 A. J. w. M. VAN OVERBEEK ETAL 2,591,981

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1947 7 Sheets-Sheet 2 Lil- April 8, 1952 A. J

W. M. VAN OVERBEEK EI'AL 'CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS 7 Sheets-Sheet 3 Filed Dec. 10, 1947 AGENT Aprll 1 A. J. w. M. VAN OVERBEEK ETAL 2,591,931

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1947 7 Sheets-Sheet 4 A.J.VV- VAN OVERBEEK Z.VAN GELDER & J.L.HJONKER INVE NTORS AGENT l 1952 A. J. w. M. VAN OVERBEEK ETAL 2,591,981

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1947 7 Sheets-Sheet 5 5 .135 A,J.VV.M:-VAN OVERBEEK ZIVAN GELDER8.J.L.H.JONK\ER INVENTORS Y B AGENT M Ap 1952 A. J. w. M. VAN OVERBEEK ETAL 2,591,981

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1947 v 7 Sheets-Sheet 6 A'.J.W- VAN OVERBEEK Z.VAN GELDER & J.L.H.JONKER I NVENTORS Aprll 52 A. J. w. M. VAN OVERBEEK ETAL 5 L 1.

CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Filed Dec. 10, 1-947 7 Sheets-Sheet 7 g E A .J.W VAN OVERBEEK Z.VAN GELDERa. JL.H.JONKER AGENT Patented Apr. 8, 1952 UNITED STATES PATENT OFFICE CIRCUIT ARRANGEMENT, INCLUDING A CATHODE-RAY TUBE COMPRISING CATHODE-RAY BEAM DEFLECTING MEANS Application December 10, 1947, Serial N 0. 790,874 In the Netherlands October 23, 1946 Section 1, Public Law 690, August 8, 1946 Patent expires October 23, 1966 .11 Claims.

The invention relates to a circuit-arrangement comprising a cathode-ray tube provided with means for deflecting the cathode-ray beam and to a cathode-ray tube'ior use in such an arrangement.

With circuit-arrangements of this kind it has often been found desirable for various uses to utilize means which make it possible in a simple manner to fix the cathode-ray beam in definite positions and to displace the beam from a position of this kind to another. Such a circuit-arrangement is suitable, for example, for use as a line selector or a group selector in an automatic telephony system, as a counting tube in a calculating machine, as a control circuit for emitting voltage pulses at regulartime intervals, as a control tube vfor barring mechanisms, for frequency division.

The circuit-arrangement according to the invention is characterized in that, atone or more positions of the cathode-ray beam, current distribution occurs to at least two collecting electrodes and in that the current passing through at least one of the circuits connected to one of these electrodes acts upon the deflection of the cathode-ray'beam so as to keep the beam in the position concerned.

It may be noted here that for example in telephony it-is known to use an automatic telephone selector which comprises a cathode-ray tube having a plurality of anodes and in which deflecting means enable direction of the beam to each of these anodes, the beam being, however, not held on a definite anode with the aid of current distribution, so that stabilizing the desired position involves a comparatively complicated circuitarrangement.

In the circuit-arrangement according to the invention-provision is made for one or more positions of the beam which are-stable by nature, :so that such a circuit-arrangement is of simple nature.

In order that the invention may be more clearly understood and readily carried into eiiect, it will now be described more fully with reference to the accompanying drawing.

In the drawing: Y 2

Fig. 1 is a schematic diagram of a circuit in accordance with the invention;

Fig. 2 is a curve explanatory of the operation of the circuit in Fig. 1;

Fig. 3 is a perspective view of the tube struc ture in Fig. 1;

Fig. 4 is an electrode structure in accordance with the invention,

Fig. .5 is a schematic diagram of a circuit in accordance with the invention;

Fig. 6 is a schematic diagram of a circuit in accordance with the invention;

Fig. 7 is a schematic diagram of a circuit in accordance with the invention;

Fig. 8 is a schematic diagram of a circuit in accordance with the invention;

Fig. 9 is a curve explanatory of the operation of the circuit in Fig. 8;

Fig. 10 is a schematic diagram of a circuit in accordance with the invention;

Fig. 11 is acurve explanatory of the operation of the circuit in Fig. 10;

Fig. 12 is a curveexplanatory of the operation of the circuit in Fig. 5;

Fig. 13 is a curve explanatory of the circuit in Fig. 1 when the electrodes therein are secondarily emissive;

Fig. 14 is a schematic diagram of a circuit in accordance with the invention;

Fig. 15 is a schematic diagram of a circuit in accordance with the invention;

Fig. 16 is a schematic diagram of a circuit in accordance with the invention;

Fig. 17 is a schematic diagram of a circuit in accordance with the invention;

Fig. 18 is a curve illustrative of the behavior of a circuit including a tube having bi-directional deflecting means;

Fig. 19 is a circuit in accordance with the invention;

Fig. 20 is a circuit in accordance with the invention;

Fig. .21 is a circuit in accordance with the invention;

Fig. 22 is an electrode structure in accordance with the invention;

Fig. '23 is a circuit in accordance with them vention;

Fig. 24 is an electrode structure in accordance with the invention;

Fig. 25 is an electrode structure in accordance with the invention; 1

Fig. 26 is an electrode structure in accordance with the invention;

Fig. 27 is an electrode structure in accordance with the invention; and

Fig. 2 8 is an electrode structure in accordance with the invention.

The cathode-ray tube I of Fig. 1 comprises means known per se and diagrammatically shown for producing a cathode-ray beam I I, a set of plates .2 for deflecting the beam and, in addition, two co1lecting electrodes 3 and 4. The electrode 3 is constructed in such manner that, upon deflection, at least part of the beam impinges either on the electrode 3 or on the electrode 4. For this purpose it may, for example, comprise separate conductively interconnected plates or it may be constituted by one plate in which properly chosen recesses are provided.

The electrode 3 is connected through a conductor 6 to the positive terminal of a voltage source, the negative terminal of which is connected to the cathode of the cathode-ray tube. The positive terminal of this voltage source is connected, in addition, through a resistance 1 and a conductor 8, to the collecting electrode 4, the end of the resistance I which is remote from the voltage source being connected to one of the defleeting plates.

In such a circuit-arrangement the current is. passing through the circuit 8 as a function of the deflection produced which is determined by the voltage difi'erence V between the deflecting plates exhibits a plurality of maxima and minima, as shown in Fig. 2 by curve II. The value of these maxima and minima and their relative position are largely determined by the dimensions and the arrangement of the two electrodes 3 and 4 and by the shape and size of the sectional area of the cathode-ray beam. The voltage V set up across the deflecting plates and obtained from the resistance I, linearly varies with the current is passing through this resistance, this relation being shown in Fig. 2 by the resistance line l2. In this case the resistance 1 is such that the line I2 intersects the curve II at a number of points. The points of intersection designated I3, I4, I5 and I6 yield stable,positions for the cathode-ray beam. If, for example, the voltage V increases from point I 4, this involves an increase of 2 2. along the curve I I, but, in accordance with the relation represented by the line l2, this increase of is results in a decrease of V, so that the increase of V is thus counteracted and return to the position I4 will be effected.

It is furthermore often found to be favourable if the maxima and minima of Fig. 2 vary monotonously and in the same sense as functions of deflection. Thus for example, in Fig. 2 at an increasing deflecting voltage V both the minima and the maxima decrease in value more and more. This is advantageous if it is desired to do away with the points of intersection by turning and displacement of the straight line I2, since inthis case a smaller rotation of this line will generally be required than in the case of arbitrary variation of the values of the maxima and minima as functions of V.

This will be more obvious with reference to Fig. 3 which shows diagrammatically the arrangement of the electrodes in accordance with the circuit-arrangement shown in Fig. 1. The reference numerals of this figure correspond to those of Fig. l. V

If the centre of the sectional area of the beam II impinges upon, for example, the centre I8 of one of the sections of electrodes, the current is passing to the electrode 4 is a minimum, which corresponds, for example, with point I9 of Fig. 2. This causes the voltage across the end 20 of the resistance I to differ only little from the battery voltage, so that the beam moves to the right and, owing to the current distribution which occurs, the current is. is increased with the result that the voltage across point 20 is decreased and the movement of the beam comes to a standstill if point I4 in Fig. 2 is reached, the beam falling in 4. part on to the electrode 3 and in part on to the electrode 4.

With regard to the circuit-arrangement referred to above it may be noted that as an alternative the deflecting voltage may be obtained from a resistance included in the conductor 6; in this case the beam is not adjusted on the righ-hand edge of the electrode 3 shown in Fig. 3 but on the left-hand edge. As an alternative, deflection may be eflected in such manner that the voltage for the one deflecting plate is taken from a resistance included in the conductor 6, whereas the voltage set up across the resistance 1 is fed to the other deflecting plate; in this case the stabilizing elfects will support one another. It will also be obvious that the electro-static deflection may be replaced by electromagnetic deflection, if a deflecting coil is included in the circuit 6 and/or 8.

In addition, it is not necessary that the beam as a whole should take part in the current distribution, in which case the centre of the sectional area of the beam traverses the dotted lines which in Fig. 3 are indicated on the electrode. The path of the beam may, for example, be such that the path described by the centre of the sectional area lies higher than is indicated in the figure, so that only part of the beam assists in current distribution, whereas the remaining part of the beam may be used for other purposes, the first-mentioned part of the beam thus ensuring stable adjustment to a given position as required in view of further use.

In addition, the electrodes need not be arranged one behind the other in the direction of the oathode-ray beam but may be arranged alternatively side by side, as long as the arrangement is such that at a number of beam positions current distribution to the electrodes occurs. Such a set of electrodes may, for example, be constructed as the electrodes 20 and 2| shown in Fig. 4. Both electrodes have projecting parts which partly interengage one another. The centre of the beam 23 describes the line 22 during deflection and in order to obtain current distribution, the distance d between the projecting parts of the electrodes is smaller than the largest dimension a of the beam-section chosen in the direction of movement. In the circuit-arrangements shown it may furthermore be useful, in addition, slightly to vary the positions of the beam, which may be effected by varying the resistance 1, with the result that rotation of the resistance line I2 of Fig. 2 is brought about so that the intersections [3, I4, I5 and I6 change places.

For displacing the beam from one position to another a voltage of suitable value and suitable polarity may be fed to the deflecting plates, for example through the conductor II]. If the beam originally occupies, for example, the position corresponding to point I6 in Fig. 2, a voltage V16 being set up between the deflecting plates, this voltage will have to be reduced finally to V15 in order that the beam may reach a position corresponding to point 15. Seeing the stable condition of each adjustment, it is obvious that a certain tolerance of the voltage to be supplied is allowed, since the current partition results in a reaction which repels the beam to the point I5 if the voltage supplied differs slightly from V16 and V15. If the plates 2 have supplied to them, through the conductor ID, a voltage of the approximate value of V16, V15, there will be set up across the resistance 1, owing to the change in position of the beam, a Voltage drop which, owing to the permanent presence of the capacity 9, approaches comparatively slowlyto the value viii-V15. In order :ilnally to obtain the desired deflecting voltage Visit is therefore desirable to supply-through the conductor Illa positive voltage :impulse which abruptly attains the value V1e-V15 and then decreases with a speed which is equal to the speed :with which the voltage drop across the resistance 1 taiies3place, so that the deflecting voltage .is abruptly altered to the extent of the required voltage and consequently exhibits a characteristic response curve. This may be achieved, for example, by supplying a rectangular voltage .impulse'to a :network, the time constant of which is :equalto the time constant of resistance! and'capacity 9, the output voltage of this network being then supplied to the conductor l0. Such a circuit-arrangement is shown inFig. '5 and comprises a resistance :21 and-a condenser 26. They havegsupplied to them a rectangular impulse 28 fordisplacement of the beam. If several of such impulses are fed to the deflecting plates, the "beam. moves, .for example, from the position associated with the highest deflecting voltage, point in Fig. 2, in a stepwise manner to the position with the lowest deflecting voltage, point 13 in Fig. 12'. The beam may becaused to return to point l-B either stepwise or at a stretch by'rsupplying negative impulses of suitable value to the network 26, 21 or by temporarily short-circuiting the resistance 7, but for various usesof 'the ci-rcuit-arrangement it is desirable that means should be available which ensure that after a definite position is reached displacement of the beam to a iurther position is automatically achieved.

This may be effected, ior eigample, by means of the circuit-arrangement,shown diagrammatically in Fig. 5, there being-connected in parallel with the resistance 1 a 'gasfilled discharge tube 24, the anode ofwhich is connected to that end of the resistance 1 which is connected to the positive terminal of the voltage source. With decreasing deflecting voltage the voltage difierence across resistance 1 increases and the i nition voltage may be chosen to be such, if necessary with the aid of a suitably chosen voltage of the control-grid 25 that at a definite position of the beam, for example corresponding to point I3 of Fig. 2, the tube ignites; This causes a material reduction of the resistance of the parallel combination-of resistance -1 and-tube 24,, which means in Fig. 2 that the resistance line l2 tends to occupy a considerably steeper position, so that intersections with the curve N no longer occur. The volta e across resistance is decreased and the beam --moves to the right until the tube 24 .extinguishes and 'thezresistance line 12 ire-appears. "I'he 'beammoves-tofthe nearest stableposition so that, if the extinction voltage of the tube is .so low that itdoes :not extinguish until the beam, movingiromleft'to right, has passed position 16, the beam will return to position [6 after extinction.

In a further embodiment the =cathoderay tube is provided with :a supplementary collecting :electrode, on which the beam impinges when occupying a position associated with a definite deflecting voltage, a pulse lbein'g abstracted from the circuitsconnected to this collecting electrode for the-purpose of displacing the :beam to a further position. Figs. 6 and '7 diagrammatically show two circuit-arrangements of this kind. In both circuit-arrangements the supplementary collecting electrode 29 is arrangedfin such manner that, if the beam finds its way to the position 'associated with the lowest deflecting volta e. this being position J3 in .Fig. 2, it impinges on this supplementary electrode. In the circuit-arrangement shown in Fig. '6 this electrode is connected through a condenser tothe anode of a discharge tube 30 whichisincluded in a blocking oscillator circuit 'known perse. This tank circuit is adjusted in .such manner that not until the beam reachesthe electrode 29 it becomes operative .owing to the positive voltage impulse occurring across the grid circuit of the oscillator. This causes a positive voltage impulse occurring with asmalltime-lag to -be setup, through a coupling condenser at the right-hand deflecting plate, so that :the .beamis moved to the right. By correct proportioning the beam is moved by the impulse voltage to the first stable position or even farther back, after which the beam, at the end of the impulse, occupies that position.

If, in the circuit-arrangement shown in Fig. '7, the beam strikes the electrode 29, a voltage drop occurs .across the resistance 3| so that, in a slightly delayed manner, owing to the pres- 'ence of the resistance 32 and the condenser 33 the'voltage of the electrode 34 is-also decreased; this electrode acts as the anode for the cathoderay tube. .The strength of the beam current is thus reduced, so that the curve II in Fig. 2 as a whole becomes located so much lower that intersections with the .line [2 no longer occur and the beam moves to the point 36 located entirely-at the right of the figure.

A further circuit-arrangementis shown in Fig. 8,:a voltage-pulse being repeatedly supplied-across theresistance ,2! and the condenser 26 for the stepwise displacement of the beam. As soon as the beam has gained the position in which the supplementary suppressor-electrode 29 is struck, the voltage across the resistance 2'! decreases, so that the deflecting voltage prevailing between the plates 2 .is reduced and the curve ll of Fig. 9 shifts relatively to the resistance line I2 to a position l I, in which intersections with the line l2 no longer occur. This results in the beam returning to point 36.

.In a further circuit-arrangement set out more fully with reference to Figs. 10 and 11 the circuit 8 which comprises the resistance 1 from which a deflecting voltage is obtained is fed through a potentiometer, which comprises a discharge tube 31 and a resistance 38. The control-electrode of the discharge tube has supplied to it a voltage from 'a potentiometer 39, 49 which is connected on the one hand to :one of the deflecting plates land ontheother hand to the negative terminal of .a battery 42. Aslongasthe cathode-ray beam occupies one of .the positions which .correspond to a comparatively high deflecting voltage the voltage of .thecontrol-electrode of the discharge tube is positive and the total .resistance of the reacthre circuit 8 is in which R1 designates the resistance of the discharge tube 31, the relation between the current strength is, in the circuit 8 and the deflecting voltage V occurring being represented by the line 43 of Figpll. 'If, after the required voltage'impulses have been supplied to the network 26, 21 in succession, the cathode-ray beam occupies the position corresponding to point 44 .of F'ig. l -L'the'voltage occurring on a control-electrode of the tube '31 has become substantially zero. If the beam is then moved into position corresponding to point 45, the voltage '61: the controlelectrode becomes negative to such an extent that the tube 31 is disabled. This causes the current passing through the resistance 38 to decrease and the line 43 to be replaced by the line 46, which does not yield any intersections with the curve 41, so that the beam will move to point 48 and then, after the tube 31 has again been made conductive, occupy the position corresponding to point 49. In order that tube 31 may be kept for some time in cut-off position provision is made of a condenser 4|, which is proportioned such that the time constant C41R4o C9R7=C2sR2m It is, in general, advisable to choose the dimensions and the arrangement of the collecting electrodes to be such that the value of the maxi mum of current strength which occurs for the position at which the beam is desiredto be returned to another position is much higher than the value of the other maxima. If the current ia exhibits, for example, the shape 50 (Fig. 12) and if position is that at which the beam is moved back to position 5'2, it is favourable if the maximum 53 considerably exceeds the other maxima. The use of, for example, a circuit arrangement as shown in Fig. 5 results in the occurrence of the resistance line 54, for example during the displacement of the beam from position 52 to position 5|. When the position 5! is gained, the said resistance line changes, for example, to the line designated 55, but the potential of the left-hand deflecting plate does not vary and variation of the potential of the right-hand deflecting plate due to theoccurrence of the time constant R109 requires a certain amount of time. 'I'his'results in the passage of an alternating current in the circuit 8, so that an alternating voltage is set up across condenser 9 which is lower according as C9 is higher and R709 lower. If the maximum 53 of the current strength (Fig. 12) is high, the position variation of the resistance line 54 to the position 55 is large, so that the latter line is caused to be spaced a comparatively large distance away from the other maxima. This is particularly important in the proximity of the maxima 56, 51 and 58, where the speed of the beam becomes low, so that a comparatively high alternating voltage is set up across the condenser 9 and this enhances the possibility of obtaining an erroneous position of the beam.

In one favourable embodiment of the circuitarrangement according to the invention one or more of the said collecting electrodes with which the current that passes through the circuit connected thereto acts on the deflection of the cathode-ray beam are constructed in the form of secondary-emission electrodes. Secondaryemission electrodes of this kind permit of readily obtaining a current strength in the circuits connected to the said electrodes which exceeds that of the above described circuit-arrangement and owing to which the sensitiveness of the circuit-arrangements is enhanced.

A circuit-arrangement of this kind, which may otherwise be, for example, of the kind shown in Fig. 1, will be explained more fully with reference to Figs. 1 and 13, it being assumed that the electrode 4 of Fig. 1 is constructed to operate as a secondary-emission electrode having a secondary-emission factor exceeding 1. If the current in passing in the circuit Sis assumed to be positive if it flows in the direction designated by the arrow, the relation between this current and thdeflecti'ng voltage and, 'in'addition,'the re-- sistance lines are representedby the curve 60 and the straight line Bl respectively in Fig. 13. For the stepwise displacement of the beam use may again be made of the circuit-arrangement as shown at the left of Fig. 5. Even for displacing the beam after it has gained a definite position use may furthermore be made of the recognition underlying the circuit-arrangement shown in Fig. 5 so long 'asthe connections of the anode and the cathode of the tube 24 to the resistance 1 are interchanged.

Fig. 14 shows the circuit-arrangement for the recurring movement of the beam, in which a discharge tube is connected in parallel with the series combination of aresistance 62 and a supply battery 63. The battery 65 and the anode 66, which is connected to the right-hand deflecting plate 61, have connected between them a potentiometer 68, 69, from which a control voltage for the discharge tube is obtained. on displacement 'of the beam from the position 10 in Fig. 13 to the position 1|, the current is. increases in a negative sense, so that the voltage of point 12, Fig. 14, increases; The potentiometer 68, 69 and the voltage of the battery 65 are chosen to be such'that the tube 64 continues to be disabled. At the next position of the beam 13 in Fig. 13 the anode voltage of the discharge tube continues to increase, so that the tube passes current with the result that the resistance from which the deflecting voltage is taken decreases and the line 6| of Fig. 13 consequently assumes a steeper course and no longer intersects the curve 60 whilst at the same time the voltage of poin't 12 is reduced. This causes the beam to move to the left and to find its way to point 10. Also in this circuit-arrangement a condenser 14 is arranged between the control-electrode and the cathode of the discharge tube, in order to keep the resistance line 61 for some time in the steeper position by maintaining the tube 64 to be conductive. For obtaining an adequate amplification factor use is preferably made of a tetrode or a pentode as to constitute the discharge tube.

In the case of secondary-emission collecting electrodes use may also be made of a circuit-arrangement of the kind shown in Fig. 10 for the purpose of displacing the beam. In this case, however, care has to be taken by proper choice of the resistances 39, 40 and the battery voltage 42, to make sure that the tube is continuously disabled, except in that position from which the beam is required to be moved back. As long as the beam has not yet gained the position 13 in Fig. 13, the tube is consequently disabled. On the beam gaining the position 13, so that the tube becomes conductive, the external resistance in the circuit 8 de'creasesand the deflecting voltage is reduced. Similar t'o'the circuit-arrangements comprising non-secondary-emission electrodes, which permitof using a supplementary electrode'which is struck by-the beam in one definite position of the latter, a circuit-arrangement having one or more collecting electrodes constructed as secondary-emission electrodes permits the use of a supplementary electrode which is also constructed to have a secondary emission. Such a circuit-arrangement, the operation of which is similar to that of Figs. and 8 and in which again displacement of the characteristic curve takes place, is shown in Fig. 15.

Here the electrodes 11 and 18 are realised as 9" secondary-emission electrodes. After the beam has moved farther and farther to the right under the action of several voltage impulses supplied at 83, it impinges at the last stage on the electrode 18, with the result that the voltage across the resistance 82 increases and the displacement of the characteristic curve is obtained.

In the circuit-arrangement shown in Fig. 16 use is also made of a supplementary secondaryemission collecting electrode. If the beam impinges on this electrode 84, a resistance 85 has set up across it a positivevoltage; impulse which is supplied through a potentiometer 86 to the control grid of a discharge tube 81 included in a blocking oscillator circuit. The voltage across this control-grid is adjusted such that the tube does not ignite until this impulse occurs. Consequently, a moment afterwards the control-grid circuit of this tube has set up across it anegative voltage impulse which is fed to the right-hand deflecting plate and displaces the beam to a further stage in accordance with the value of the negative impulse.

Fig. 17 shows a circuit-arrangement in which reduction in current strength of the cathode-ray beam is again utilized. Connected in parallel with a resistance 89 included in the supply circuit of the anode 8-8 is a discharge tube 93. This tube is normally disabled by means of a battery 9E and a potentiometer 9|, 92. When a definite position of the beam is gained, the voltage at the end 96 of the resistance 30 included in the circuit of the secondary-emission collecting electrode 91 is, however, increased to such a value that the tube 93 ignites, with the result that the voltage of the anode 88 is reduced. This causes the current strength of the beam to decrease to such an extent that intersections no longer occur and the beam moves to the position with the lowest deflecting voltage.

In the examples hitherto described there was always available for the sake of simplicity a cathode-ray tube in which the beam, under the action of the deflecting means, was only subjected to a deflection in one plane so that the end of the beam performed a one-dimensional movement. It is known that a two-dimensional movement of the end of the beam may be obtained in a simple manner by the use of suitabledeflecting means. Even in the case of such a' movement of the beam adjustment to a plurality of positions may be obtained in a simple manner, as will be explained more fully with reference to Fig. 18. Under the action of two de flecting systems, for example, deflection coils, the terminal point of the beam is adapted tomove in the plane XY, one coil influencing the deflection in X-direction and the other coil the deflection in the Y-direction. The coil influencing the deflection in the X-direction is included in the circuit of a collecting electrode which takes part in the current distribution. Consequently, there is a relation between the current i1 passing in the coil and plotted in a vertical direction and the point X of the beamend, this relation not being indicated by a line, but, as a result of a potential displacement in the Y-direction, by the plane 11. Due to the current distribution occurring and the shape and spacing of the electrodes there is also a relation between the current is. passing in the coil and the position of the end of the beam, represented, for example, by the plane B. These two planes exhibit one or more lines of intersection L1 which corre-' sponds to the potential stable adjustments of 10' the beam. Now, if a coupling is realized between the coil controlling the deflection in the Y-direction and a further electrode participat ing in the current distribution, a similar figure is produced, which exhibits one or more lines of intersection Lz, only the intersections of the projection's'of the line systems L1 and L2 on theXY- plane corresponding with stable adjustments of the beam.

It is obvious that there are many circuit-arrangements which permit of realizing this twodimensional stabilization of the beam in a plu-- tion. On the beam striking the electrode 98,

deflection is produced in the direction of the arrow indicated in this electrode, whereasin the case of the electrode 99 being struck de-- flection is produced in the opposite sense. The electrodes I60 and Ifil are connected in a similar push-pull arrangement to the coil I03, with the resultv that deflections also indicated by arrows are produced in a horizontal direction. If then, by suitable deflection, the beam is moved into the proximity of a position in which current distribution to the four electrodes occurs, adjustment of the beam in a stable manner will ensue between these four electrodes in one of the positions I04, I05 or I06.

As analternative, such a circuit-arrangement may be realized with electrostatic deflection, asis shown in Fig. 20, in which the plates I01 ensure horizontal and the plates I08 vertical deflection. For the sake of simplicity only one position I09 is shown here in which current distribution to the four electrodes HG, III, H2 and H3 occurs, but like indicated in Fig. 19 for three positions, this circuit-arrangement may also be extended in an analogous manner to a plurality of positions. If the beam strikes the electrode H0, the potential of point H4 is reduced and the beam moves to the right according to the arrow. Similar considerations apply to the other electrodes. Thus the beam is ultimately adjusted in the stable position I09.

Fig. 21 shows a circuit-arrangement in which of each pair of electrodes one electrode, in this case H5 and H6, is constructed so as to have secondary emission. If the beam strikes the electrode l I 5, the potential of point I I1 increases owing to which the potential of the left-hand deflecting plate H8 for the horizontal deflection increases and the beam moves in the direction of the arrow shown in the electrode H5. If the beam strikes the electrode H9 the potential of point H1 decreases and the beam moves in the opposite direction. Displacement in a vertical direction is similarly effected with the aid of the deflecting plates I 20.

It is not only possible to cause the beam to occupy a definite position as in the case of the above circuit-arrangements, but the position of the beam may even be limited within a definite space angle.

- 'This may be realized, for example, withthe aid of a circuit-arrangement in which use is made of the electrodes shown in Fig. 22. In this case current distribution to at least one of the electrodes associated with two pairs of collecting electrodes and a fifth electrode occurs, it being possible for the pairs I22, I24 and I23, I25 again to be included in a push-pull circuit, similarly to those of Figs. 19, and 21. If the beam strikes, for example, the electrode I25, it is driven'to the right according to the direction of the arrow until it occupies a stable position, in which it partly strikes the electrode I and partly the electrode I2I. This allows adjustment of the beam anywhere on the edge of the electrode I2I.

The circuit-arrangements shown in Figs. 19, 20, 21 and 22 permit, by the supply of suitable deflecting voltages or currents, of the beam being shifted from one stable adjustment to another, either in a horizontal or in a vertical direction. If, for example, the coil I03 of Fig. 19 has supplied to it a suitable current, for example across a transformer, the beam is adapted to be moved horizontally from position I04 to I05 and vertical displacements may be effected in an analogous manner with the aid of currents passing through the coil I02.

In addition, Fig. 23 shows a circuit-arrangement for limiting the position of the beam within a definite space angle. In this case current distribution occurs to at least one of the four electrodes I26, I21, I28 and I29 and a further electrode I30 which is shown located behind the four first-mentioned electrodes. These four electrodes each consist of two parts, for example, I26 I and I25 II; these parts are arranged in such manner that, viewed from the cathode of the tube, they form two concentric rings. This, consequently, does not mean that these electrodes must necessarily be located in one plane, since they may be spaced at different distances from the cathode. The figure shows the connection between two of these electrodes and one set of deflecting plates I3I for horizontal deflection. The connection of the other electrodes to the plates for vertical deflection is similar. Owing to the reaction thus produced the beam upon impingement on one of the electrodes moves according to the arrow indicated therein, so that the position of the beam is limited to the space determined by the concentric rings.

Fig. 24 shows an electrode arrangement in which current distribution to at least one of six electrodes I32 to I31 inclusive arranged in a ring and a further electrode (not shown) arranged behind these six electrodes takes place. In order to ensure that adjustment of the beam for example on the outside of one of the electrodes takes place, these electrodes may be coupled, for example individually, to a deflection coil, these coils being arranged with a relative displacement of As an alternative, two opposite electrodes, for example I34 and I3! may jointly be coupled to one coil, the three coils thus provided being arranged at 120 relatively to one another. Such a circuit-arrangement may be readily extended to ten or more electrodes, each of which is connected to a tapping of a deflection coil which is wound in a manner as applied to rotor windings of an electric motor.

A similar circuit-arrangement may, as an alternative, be realized with electrostatic deflection, as will be seenby reference to Fig. 25. Also in this case current distribution occurs to at least one of twelve electrodes I38 arranged in accordance with the sides of a regular dodecago'n and a further electrode (not shown) arranged behind them. Each of the electrodes I38 is connected to a junction between two resistances of twelve resistances I39 included in a ring circuit. This ring circuit is supplied at four points through resistances I40, four symmetrically located points being connected to two pairs of deflecting plates I4I. Also in this case adjustment of the beam to the edge of one of the electrodes I38 takes place. It may be noted here that adjustment of the beam to the opposite edge of the electrode will ensue if there is a difference of between the connecting point of a deflecting plate and the arrangement of this plate. A similar result may be obtained if the electrodes I38 are constructed to have secondary emission.

In the case of an electrode arrangement as shown in Fig. 26 the beam becomes adjusted in one of the re-entrant angles of the regular figure formed by the electrodes. Each of the electrodes, for example I42, comprises two parts I42-I and I42-II. Upon impingement on such an electrode a displacement of the beam again occurs in the direction of the arrows shown. Also in this case current distribution occurs with a further electrode located behind the electrodes shown. The beam will become adjusted, for example, to a position designated I43.

Referring to Fig. 27 there is also obtained a reentrant angle, in which the beam becomes adjusted, such with the aid of five electrodes which are subdivided into four partial electrodes, such for example as electrode I44, the outer edges of these partial electrodes forming together a regular figure exhibiting alternately re-entrant and salient angles. For displacing the beam from one position I45 to position I46 use is made of a coil, the axis of which coincides with the connecting line between the cathode and the centre 41 of the electrode pattern. If a voltage impulse is supplied to this coil, the beam moves along a circular arc in the arrow direction shown. The connecting line between the points I45 and I41 is the centre line of this arc. If in this case the beam strikes the electrode I48, it is moved to position I46.

Finally Fig. 28 shows the electrode pattern for a circuit-arrangement, in which the beam again becomes adjusted in the re-entrant angles formed by the external edges of an electrode system, but in which displacement from one position to another is effected by means of electrostatic deflecting means. The external boundaries of the internal ring of the electrodes I again form alternately re-entrant and salient angles and these electrodes are connected to deflecting plates in a manner which is sure to be obvious after the foregoing, such that the beam becomes adjusted in the re-entrant angle, for example at I50. If the beam is given a radially-directed impulse towards the centre it finds its way to electrode I5I and is moved to position I52. The internal ring of electrodes is surrounded by a second ring of electrodes I53 which are coupledjo electrostatic deflecting means in such manner that the beam, upon impingement on these electrodes, performs a tangential movement in the direction of the arrows. With the aid of these electrodes and radial impulses the beam may be moved from the position I52 back to the position I5I.

It may in addition be noted that in the latter embodiments a regular arrangement of the electrodes has always been indicated which, however, is not indispensable, since in the case of an electrode which is spaced from the centreof the electrode pattern farther away than other electrodes such coupling to the deflecting element concerned may be provided that the reaction on the position of the beam is greater-than with the other electrodes.

What we claim is:

1. An electronic systemcomprising. a cathoderay tube provided with an electron beam source, means for deflecting said beam in a. given plane, a first collecting electrode, a second. collecting electrode interposed between said deflecting means and said first electrode and. having spaced Openings therein whose cross sectional dimensions relative to that of said beam efiect distribution of beam current betweensaid first andsecnd electrodes atevery position of said beam, a resistance, means to impress an accelerating. potential on said second electrode. and through said resistance on said first electrode; means coupling said first electrode to said deflecting means, and means to apply an external voltage impulse to said deflecting means to displace said beam.

2. An electronic system comprising a cathoderay tube provided with a source generating an electron beam having predetermined cross sectional dimensions, means to deflect said beam within a given plane, first and second collecting electrodes mounted at, spaced positions intersecting said plane, said second electrode being disposed in front of said first collecting electrode with respect to said source and having a plurality of spaced openings therein whose cross sectional dimensions are smaller than that of said beam whereby at every position of said beam its current is distributed between said first and second electrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima which vary progressivey in the same sense as a function of beam deflection, a resistance, means to impress an accelerating potential on said second electrode and through said resistance on said first electrode, means coupling said first electrode to said deflecting means, and means to apply an external impulse to said deflecting means to displace said beam.

3. An electronic system comprising a cathoderay tube provided with a source generating an electron beam having predetermined cross sectional dimensions, a pair of deflecting elements to deflect said beam within a given plane, first and second collecting electrodes mounted at spaced positions intersecting said plane, said second electrode being disposed in front of said first collecting electrode with respect to said source and having a plurality of spaced openings therein whose cross sectional dimensions are smaller than that of said beam whereby at every position of said beam its current is distributed between said electrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima which vary progressively in the same sense as a function of beam deflection, a resistance, means to impress an accelerating potential on said second electrode and through said resistance on said first electrode, means connecting said first electrode to one of said elements, and means to apply an external impulse to the other of said elements to displace said beam.

4. An arrangement, as set forth in claim 3, wherein one of said collecting electrodes is constituted by material which emits secondary electrons and has a secondary-emission factor exceeding one.

5. An electronic system comprising a cathode- '14 ray tube provided with a. source. generating an electron beam having predetermined cross. sectional dimensions, apair'of deflecting elements.

to deflect said beam within a given plane, first and second. collecting. electrodes mounted at spaced positions intersecting said plane, said second electrode being disposed infront of' said first: collecting electrode With respect to. said source and having a plurality of; spacedopenings therein whose cross sectional. dimensions are smaller than that of said beam whereby at every position. of said beamits current is distributed between saidlelectrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima whichvary progressively in thesame sense as a funtcion of beam deflection, a. resistance, means to impress an accelerating potential on. said second electrode: and through said resistance on said first electrode, means connecting said first electrode. to one of said elements, means to apply an. external impulse to the other of said elements to displace said beam, and a gaseous discharge tube connected across said resistance and having an ignition voltage response corresponding to a predetermined: voltage value across said resistance.

6. An. arrangement, as. set forth in claim 5, further including a capacitance shunted across said resistance.

'7. An electronic system comprising a cathoderay tube. provided with a. source generating an electron beamv having predetermined cross. sectional dimensions, first and second deflecting elements for deflecting saidbeam within a given plane, first and second collecting electrodes mounted at spaced positions intersecting said plane, said second electrodev being disposed in front of said first electrode with respect to said source and having spaced openings therein whose cross sectional dimensions; are smaller than that of said beam whereby at every position of said beam its current is distributed between said electrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima which vary progressively in the same sense as a function of beam deflection, and a supplemental electrode disposed adjacent one end of said first collecting electrode, a resistance, means to impress an accelerating potential on said second electrode and through said resistance on said first electrode, means connecting said first electrode to said first element, means to apply an external voltage impulse to said second element to displace said beam, a blocking oscillator including an electron discharge device having a cathode, a grid and an anode and circuits therefor, and feedback means coupling said anode to said grid, means coupling the anodecathode circuit of said device across said resistance, means to derive a control impulse from said supplemental electrode when impinged on by said beam, and means to apply said control impulse to the grid-cathode circuit of said device.

8. An arrangement, as set forth in claim 7, further including an additional resistance, and means to apply an accelerating potential to said supplemental electrode.

9. An electronic system comprising a cathoderay tube provided with a source having a cathode,

and an anode for generating an electron beam having predetermined cross sectional dimensions, first and second deflecting elements for deflecting said beam Within a given plane, first and second collecting electrodes mounted at spaced positions intersecting said plane, said second electrode being disposed in front of said first electrode with respect to said source and having spaced openings thereon whose cross sectional dimensions are smaller than that of said beam whereby at every position of said beam its current is distributed between said electrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima which vary progressively in the same sense as a function of beam deflection, and a supplemental electrode disposed adjacent one end of said first collecting electrode, a resistance, means to impress an accelerating potential on said second electrode and through said resistance on said first electrode, means connecting said first electrode to said first element, means to apply an external voltage impulse to said second element to displace said beam, means to derive a control impulse from said supplemental electrode when impinged on by said beam, a delay network, and means to apply said control impulse through said network to the anode of said source.

10. An arrangement, as set forth in claim 9, wherein said network is constituted by a resistor interposed between said anode and said supplemental electrode and a condenser connected between said anode and ground.

11. An electronic system comprising a cathoderay tube provided with a source generating an electron beam having predetermined cross sectional dimensions, first and second deflecting elements for deflecting said beam within a given plane, first and second collecting electrodes mounted at spaced positions intersecting said plane,,said second electrode being disposed in front of said first electrode with respect to said source and having spaced openings thereon whose cross sectional dimensions are smaller than that of said beam whereby at every position of said beam its current is distributed between said electrodes, beam current flowing to said first electrode exhibiting a plurality of maxima and minima which vary progressively in the same sense as a function of beam defiectiomand a supplemental electrode disposed adjacent one end of said first collecting electrode, said supplemental electrode and said first collecting electrode having secondary-emission factors exceeding one, a resistance, means to impress an accelerating potential on said second electrode and through said resistance on said firstelectrode, means connecting said first electrode to said first element, means to apply an external voltage impulse to said second element to displace said beam, a blocking oscillator including. an electron discharge device having a cathode, a grid and an anode and circuits therefor, and feedback means coupling said anode to said grid, means coupling the anode-cathode circuit of said device across said resistance, means to derive a control impulse from said supplemental electrodefwhen impinged on by said beam, and means to apply said control impulse to the grid-cathode circuit of said device to render said device conductive.

ADRIANUS J OHANNES WILI'IELMUS MARIE VAN OVERBEEK.

ZEGER VAN GELDER.

J OHAN LODEWIJK HENDRIK J ONKER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,011,920 Terry Aug. 20, 1935 2,107,410 Dreyer, Jr. Feb. 8, 1938 2,204,055 Skellett June 11, 1940 2,224,677 Hanscom Dec. 10, 1940 2,361,766 Hadekel Oct. 31, 1944 2,404,106 Snyder July 16, 1946 2,417,450 Sears Mar. 18, 1947 2,436,677 Snyder Feb. 24, 1948 2,446,945 Morton et a1. Aug. 10, 1948

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