US2561057A - Circuit arrangement comprising a cathode beam tube provided with means for deflecting the cathode beam - Google Patents

Description

July 17, 1951 J. L. H. JONKER ETAL 2,561,057

- CIRCUIT ARRANGEMENT COMPRISING A CATHODE BEAM TUBE PROVIDED WITH MEANS FOR DEFLECTING THE CATHODE BEAM Filed April 50, 1949 IIIII jau- 12 AA1AAA IIIIIII Allllll III III INVENTORY. I WHMIWWW Amuwwmms mmuwjazm K07 Patented July 17, 1951 CIRCUIT ARRANGEMENT COMPRISING A CATHODE BEAM TUBE PROVIDED WITH MEANS FOR DEFLECTING THE CATHODE BEAM Johannes Lodewijk Hendrik J onker and Adrianus Johannes Wilhelmus Marie Van Overbeek, Eindhoven, Netherlands, assignors to Hartford National Bank and Trust Conn., as trustee Company, Hartford,

Application April 30, 1949, Serial No. 90,602 In the Netherlands May 5, 1948 Claims.

The instant application i a continuation-inpart of the copendin patent application Serial Number 790,874, filed December 10, 1947.

The above-identified copending application describes and claims a circuit-arrangement comprising a cathode-ray tube provided with means for deflecting the cathode-ray beam, wherein at one or more positions of the cathode-ray beam current distribution occurs to at least two collecting electrodes and wherein the current passing in at least one circuit connected to at least one electrode which takes part in the current distribution acts upon the deflection of the cathode-ray beam so as to keep the beam in the position concerned.

According to embodiments described in the said prior patent specification, the current strength in at least one circuit connected to an electrode which takes part in the current distribution exhibits a plurality of maxima and minima as a function of deflection of the beam, and means are provided for displacing the cathode-ray beam from one position to another. Furthermore, on the beam reaching a definite position, a voltage impulse is supplied to one of the electrodes in the deflection means of the cathode-ray tube such that only one adjustment of the beam is possible and that the beam is displaced in accordance with this adjustment.

This voltage impulse is taken from a supplementary collecting electrode which is struck by the beam at a position of the beam associated with a definite deflection voltage.

Consequently, by means of this circuit-arrangement the beam may be displaced successively from one stable position to another, and if subsequently the means for displacing the beam remain operative in the same sense, the beam will strike the supplementary collecting electrode on leavin the last stable position and resume, for example, the first possible stable position.

The present invention has for its object to provide a circuit-arrangement which permits the beam to resume the first stable position, also on traversing the stable positions in the opposite direction, upon reaching and being displaced beyond the last stable position.

The circuit-arrangement according to the invention is characterized in that the cathode-ray tube comprises a second supplementary collecting electrode which in a position of the beam corresponding to a dilferent definite deflecting voltage is struck by the beam, from which second supplementary collecting electrode a voltage impulse is taken under the action of which the beam is displaced to only one other possible position.

In order that the invention may be clearly understood and readil carried into effect, it will now be described more fully with reference to the accompanying drawing, given by way of example.

In the drawing:

Figure 1 is a schematic diagram of a cathoderay tube circuit in accordance with the invention,

Figure 2 is a graph illustrative of the invention, and

Figure 8 is another graph illustrative of the invention.

In this drawing Fig. 1 represents one embodiment of the circuit-arrangement according to the invention, Figs. 2 and 3 representing currents and voltages appearing in thi arrangement.

The circuit-arrangement shown in Fig. 1 comprises a cathode-ray tube (not represented) which contains a cathode l, diagrammatically represented means producin a cathode-ray beam, deflection plates 2 and 3 and collecting electrodes 4 and 5.

The collecting electrode 4 is placed in front of the collecting electrode 5 and provided with apertures or composed of separate plates which are coupled electrically in such manner that the current in. in the output circuit of the electrode 5 exhibits a number of maxima and minima as a function of the deflection voltage V at the plates 2. 3, as is shown by the curve b in Fig. 3.

Both the collecting electrode 5 and the deflection plate 2 are connected to the end 6 of a resistance 1, of which the other end is connected to the positive terminal of a voltage supply.

Consequently, a linear relation represented by the straight line 0 in Fig. 3 exists between the deflection voltage V and the current is traversing the resistance.

If this resistance 1 has a suitable value, the curve b and the straight line 0 exhibit a plurality of intersections, the intersections A, B, C and D corresponding to stable positions of the cathodebeam.

Fig. 2 substantially corresponds to Fig. 3. but

curve b in Fig. 3 on the right of point D exhibits a maximum which is greater than the case with curve (1 shown in Fig. 2.

The circuit-arrangement described in the said prior patent specification will now be more fully explained with reference to Fig. 2. It is described in the said prior patent specification that the beam i adapted to be displaced from one posi tion to the next by means of suitable voltages which aresupplied to the deflection plates. If, for example, the beam occupies the position corresponding to point D in Fig. 2, the beam may be displaced to a position corresponding to point C by supplying, by way of the input circuit 8, 9, a suitable voltage increase of short duration to the deflection plate 3, with the result that the totally operative deflection voltage is reduced to a volt age substantially corresponding to that at point C.

By means of further voltage impulses the beam may ultimately reach the last stable position A.

If the supply of voltage to plate 3 remains operative in the same sense, and consequently a subsequent voltage impulse is supplied, the beam strikes a collecting electrode l also housed in the cathode-ray tube, which electrode is con nected, across resistance II, to the positive terminal of a voltage supply.

Due to this, the potential of this collecting electrode decreases, which decrease is transferred to the deflection plate 2 by way of a capacity l2, so that the total active deflection voltage is further reduced. As a result thereof the beam moves further to the left, which movement is contributive to the terminationof the voltage drop at 6, since the beam leaves the collecting electrode I0. On the other hand, however, no further current flows to the collecting electrode 5, owing to which the potential considerably increases at 6 and the beam is swiftly shifted to the right.

Though the said fiy-back of the beam may be explained by a shift of the resistance line c with respect to the curve a, since a diiferent straight line relationship occurs when the beam strikes the collecting electrode Ill, use will be made, for

the sake of clearness, of an explanation according to which the disappearance of the stable points A to D inclusive is ascribed to a shift of curve a with respect to the straight line 0. This explanation is exactly equivalent to the explanation involving the shift of the line a and clearly illustrates the phenomena described hereinafter.

Owing to the further drop of the total active deflection voltage the curve a in Fig. 2 is dis placed, with respect to line 0, to a position a indicated by a broken line in Fig. 2. This curve a does not intersect the straight line 0, so that the beam is adapted to move to the right and reaches the point E, whereafter the stable position D is reached.

In order to cause the beam, on traversing successively the stable positions in the sequence A, B, C and D, to resume automatically the position A, the cathode-ray tube comprises a second supplementary collecting electrode I3 at the other side of the system 4, 5, which electrode is likewise fed across a resistance l4 and connected to the deflection plate 3 by way of a condenser l5.

If, consequently, starting from position A, a voltage drop of short duration is every time supplied to the input circuit 8, 9 with the result that the deflection voltage is every time increased, the position D is ultimately reached;

Upon the next voltage variation, the beam strikes the collecting electrode l3, as a result of 4 which voltage drop is transmitted to the deflection plate 3 by way of the capacity l5. Due to this, the total active deflection voltage increases and curve a is displaced to the position a" (partly represented) with respect to the straight line 0 in Fig. 2.

Since, however, curve a exhibits a considerable decrease at the lefthand side of the stable point A, which decrease extends beyond the last preceding minimum P of the curve, not all intersections are eliminated by this displacement, so that a stable position A" remains and the beam ultimately reaches point A.

In the absence of this intersection A" the beam would move further to the left, strike the next collecting electrode l0 and subsequently be displaced again to the right.

If, however, the curve has the shape a shown in Fig. 2 a difliculty will be experienced, since, if the beam is successively displaced from position D to position A, it strikes the collecting electrode [0 upon the next voltage impulse, with the result that curve a is displaced to position a and the beam moves to the right. Since there are no intersections with the straight line 0, it is dis placed entirely to the right, strikes the second supplementary collecting electrode l3 and so eventually reaches point A under the aforesaid action.

To prevent this, the position of the electrode 4 with respect to the electrode 5 is so chosen and the apertures in the electrode 4 are provided in such manner that the current fed to the electrode 5 is a function of the deflection voltage, as is shown by curve b in Fig. 3.

In this event, consequently, this current ex hibits a considerable increase at the right hand side of point D, which decrease attains a value exceeding that of the last preceding maximum 'l between points A and D.

When the beam moves from position D to position A and the supplementary collecting electrode I0 is struck, the curve 12 is displaced to position b and one point of intersection D remains. In this manner the beam reaches point D and is prevented from striking the collecting electrode l3 and from resuming position A.

If the two supplementary collecting electrodes l0 and I3 are secondary emission electrodes, the deflection plate 2 is connected, by way of a condenser, to the collecting electrode l3, the deflection plate 3 being connected to the collecting electrode l0 through a capacity.

which the voltage set up at this electrode drops, 76

What we claim is:

1. In an impulse counting system, the combination comprising a cathode-ray tube provided with an electron beam source, first and second deflecting electrodes for deflecting said beam within a given plane, first and second collecting electrodes mounted at positions intersecting said plane, and a reset collecting electrode'disposed adjacent one side of said first collecting electrode, said first and second collecting electrodes having respective shapes and having positions relative to said plane at which beam current flowing to the first collecting electrode exhibits a plurality of maxima and minima as a function of beam deflection, first and second resistances, means to apply a constant voltage to said second collecting electrode and through said first resistance to said first collecting electrode, means to apply a constant voltage through said second resistance to said reset collecting electrode, means connecting said first collecting electrode to said first deflecting electrode, whereby the voltage drop developed across said first resistance is impressed on said first deflecting electrode, said first resistance having an ohmic value at which at a number of resultant voltage values on said first deflecting electrode the current flowing to said first collecting electrode and the current through said first resistance are equal to each other, at which voltage values the beam assumes a stable position, means to apply an external voltage impulse to said second deflecting electrode to displace said beam from one stable position to another whereby said reset collecting electrode is struck by said beam after departing from the last stable position on the side of the first collecting electrode to which the reset electrode is adjacent upon application of a votlage impulse displacing said beam in the direction of said side, and a capacitance coupling said reset electrode to said first deflecting electrode, whereby the potential on said reset electrode when struck is applied to said first deflecting electrode to displace the beam to the stable position on the other side of said first collecting electrode. 2. An arrangement, as set forth in claim 1,

wherein said second collecting electrode is disposed in front of said first collecting electrode with respect to said beam source and is provided with spaced apertures through which said beam impinges on said first collecting electrode.

3. An arrangement, as set forth in claim 1, wherein said reset electrode is formed of material which is emissive of secondary electrons.

4. An arrangement, as set forth in claim 1, wherein said cathode-ray tube is further provided with a second reset collecting electrode disposed adjacent the other side of said first collecting electrodes, and further including capacitive means coupling said second reset electrode to said second deflecting electrode.

5. In an impulse counting system, the com- W bination comprising a cathode-ray tube provided with an electron beam source, first and second deflecting electrodes for deflecting said beam within a given plane, first and second collecting electrodes mounted at spaced positions intersecting said plane, said second collecting electrode being disposed in front of said first collecting electrode relative to said source and having spaced apertures therein and a pair of reset collecting electrodes disposed on either side of said first collecting electrode, means connecting said first collecting electrode to said first deflecting electrode, first and second capacitances connecting said reset electrodes to said first and second deflecting electrodes respectively, and means to apply external voltage impulses to said second deflecting electrode.

JOHANNES LODEWIJK HENDRIK JONKER. ADRIANUS JOHANNES WILHELMUS MARIE VAN OVERBEEK.

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

UNITED STATES I PATENTS

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