US2657330A - Electric circuit comprising a cathode-ray tube - Google Patents

Description

Oct. 27, 1953 e. HEPP 2,657,330

ELECTRIC CIRCUIT COMPRISING A CATHODE-RAY TUBE Fil-ed June 20, 1950 IN V EN TOR.

GERARD HEPP WWW AGENT Patented Oct. 27, 1953 UNIT ED STATES PAT EN T OFF ICE Thisinvention' relates to" ci'rcuit's comprising a; catliode--ra-y-- tube having means for producing and deflecting a cathode ray beam, in which a collecting electrode-system is conn'ectedt'o' a de fiection electrode such'th'at the beam i's'a'dapt'ed" 5 to occupy any of aplurality ofnaturally stable positions, and in which means areprovided for displacing the'beam from-onestable positionto a subsequent-position.

In' aknowncircuit of this kind the beam" is 10 held fast in the various stable positions in'that in each position thebeam current is divided between afirst collectingel'ectrode and a further collecting electrode. The first collectingel'ect'r'ode is; on'

theme hand; connecteddire'ctly to-adeflection electrode and, on the other hand; by way of a resistanceto'a source-of supply; In-a position of equilibrium '2; current flows to the first collecting electrodeand through theresistance soas to p'ron di1cesuch deflection" voltage as" is required to maintainthe beam atthisposition';

If, for some reason or other; the beam" is slightly deflected from'a position of equilibrium and ifit moves;- for example; toward's'thafi'rst collecting" w electrode; the current flowihgtlirough this ele'ctrode'and the; resistance-increases. The deflectiorr voltage is thus "varied in suchasense that the movement is counteractedandth'e'beani'is di'iven back to the position of" equilibrium concerned; w

m a: further" known circuit" the cathode-way" tubecomprises a plurality ofcolle'cting electrodes connected to taps'on' a potentiometer," on'e'eri'd of Which'is coupled toa' defiectionelectrodez The" taps" are chosen to be such that; if the bean 1 strikes one 'collectingelectrodey a" defl'ection voltage is produced such as is required to direct the" beam to the 'electrode' concerned;

In a modified' 'form of this circuitthe-poten tiometer= also servesas a collect'in'g electrode, which in' this case" is constructed -asa resistance electrode having a resistance varying: in astep Wiserm'anner in'the': direction of deflection In these circuits different deflection: voltages correspondto-therespective stablepositionsa The beamwmay beimovedzfrom onevstable position to asubsequentiposition bysupplying a pulse toi the deflection system. This object maybe attained in known manner by deflectingthe beamnwith the: use of separate,deflectiomelectrodes inw a direction such that the beam leaves thestable'position and-moves. automatically: to a subsequent position; As :an' ialternative a pulse-:may be=super-- poserlaon'the stabilizing'defl'ectionavoltage so-that thi voltage; is: suddenly. atteredito zhaveeagivaluei 2. which; at Ieast approximately, corresponds to that associated with a subsequent position of equilibriumi Such circuits are particularly suitable to be used for counting purposes, for examplein-a' carcula'tingmaichine; since the position of thebeani provides an indication of thenumb'e'r ofpuise's suppliedto'thfe circuit.

As a rule, thenumbefof stable position'sis t'en", so that the number of pulses ma bere'cordedin a de'cinialsystern.

In" order to move th'ebe'ani' back, tdafpred'e termine'di'n'itial position after allthe"stable positions" have" been traversed successively," use made of an auxiliary"collectingelectrodewhich is struck by the" beam in an" ext're ne position and which has derived from it aomsewhith'is"sup: plied" to the deflectiorisyst'eni" or"to' ariihtensitycontrol electrode of the" tube and which' brin s" about fly-b'ack" of the" seam. Duriifg fly-back; the deflection" voltage varies in sucnmahner th'a't the b'ea'ni' automaticauymoves to its" initlalpo sition. 1 l

Inpractice a" need is "felt" fo'ra tii'bedesighed to recordiri' a givewnumeiicaisystem a'hdeic hibitiii' for example; ten stable positions; which" may a1so-heuseu with" a difirent numerical si tem such that tit-steamismoved'back to the" initial position" after, for eXarhpl'e; every 9'" or 8 puls'esi According" t'o'the" invention, this object is at-' tained" in that the deflection" electrode 1 which stabilizes" thebeani' is coupled by way of a rec: tifie'r to" a source" of Voltage whose magnitude is adjustable.

Diiri'ng fly-back, the deflection vo'ltage varies and'th'e beam moves'towar'dsthe"natural" initial osition oftl'iebeam.

When a predetsrmmed deflection voltage is" exceeded; the" rectifier becomes conductive; so" that theidefi'ction voltage" c'annotva-ry tosuch extentthat the" beam'" can fall Within" the at traction" sphere of the natural initial position? The beam" then f alls -withih the attraction sphere" of another stable' position which then" fulfillsthe function of "an initial position. I

In order that the invention" may be" clearly" understoodand" readily carried into eifecti it Will IiOW be"dSC'Iibd iIT detail by IEflfib't6" I the accompanying drawing, wherein:

Fiig'i 1" showsa" circuit in which the beam is" Sta biI i Zd bY ruean's"-- of" division Of'hiliiilt, anli Fig. 2 shows a diagram witlftlieusebfwhich' the operation oFthe-circu-it" will be explained.

The cathode 'r'ay tube I in Fig. 1 comprises cathode and focussing electrode means 2 and 3 known per se and shown here only diagram matically, for producing a cathode-ray beam, 2. set of deflection plates 4 and 5 for deflecting the beam, and collecting electrodes 5, 1,12. The electrode 6 is arranged in front of the electrode I and has a number of apertures such that the beam upon being deflected alternately strikes an element of the electrode 6 and, through an aperture of this electrode, an element of the electrode 1.

The current flowing to the electrode I then varies as a function of the deflection voltage at the deflection electrode 5, as shown by curve 2| in Fig. 2. If the beam falls through an aperture of the electrode 6, the full beam current flows to the electrode 1. If, however, the beam is intercepted by the electrode 6, the current flowing to the electrode 1 is zero.

The electrode 7 is connected through a conductor 8 to the deflection electrode 5, which is furthermore coupled by way of a resistance ID to the positive terminal of a battery I l.

The negative terminal of the battery is connected to the cathode 2 of the cathode-ray tube. The collecting electrode 6 is directly connected to the positive terminal of the battery. A suitable voltage is supplied to the deflection electrode 4, which co-operates with the electrode 5 in a manner which is not shown.

The relation between the current traversing the resistance Ill and the Voltage of the electrode 5 is shown by the straight resistance line 20 in Fig. 2. If the resistance is not traversed by current, the. voltage equals the battery voltage Vb. Upon increasing current the voltage at the point 9 decreases.

In a position of equilibrium the current traversing the conductor 8 equals the current traversing the resistance H], which implies that the positions of equilibrium of the beam are required to correspond to intersections of the curves 26 and 2! in Fig. 2.

The intersections 22, 23, 24, 25, 26, 21 correspond to stable positions of the beam, whereas the intersections 28, 29, 30, 3!, 32 provide unstable positions of equilibrium of the beam. This may be appreciated from the following:

It is assumed that at a given moment the voltage at point 9 is V2. The current flowing through the conductor 8 then exceeds the current flowing through the resistance I 0. Gwing to the difference in current, the natural capacity or condenser coupled to the point 9 and designated C in Fig. 1 is discharged. The voltage of point 9 will thus decrease and the beam moves towards the stable position of the beam corresponding to the intersection 26. Similar reasoning applies if the voltage is slightly lower than the voltage V1 corresponding to the intersection 25. Consequently, the beam will automatically move to this stable position if the voltage of the point 9 lies within the interval between the voltages V3 and V4 corresponding to the metastable positions of equilibrium 3! and 32. This interval thus constitutes the attraction sphere of the stable position 26. Similarly, the voltages exceeding the voltage V5 corresponding to the metastable position 29 are associated with the attraction sphere of the natural initial position 22. The figure shows, by way of example, only 6 stable positions. It is evident that the number may also be greater or smaller.

As already mentioned before, in practice use is mostly made of ten positions. The beam may be moved from a stable position to a subsequent position by supplying to the point 9 a pulse such that the voltage of point 9 is abruptly varied to have a value which lies within the attraction sphere of the desired subsequent stable position.

As an alternative, a pulse may be supplied to the deflection electrode 4 in a manner as described in the copending U. S. application S. N. 790,874, filed December 10, 1947.

It is assumed that the beam originally occupies the initial position 22. The first pulse then moves the beam to position 23 and after five pulses the beam has reached the position 27. The beam is moved back to the initial position by the sixth pulse. This process is accomplished as follows.

In the tube an auxiliary collecting electrode I2 is arranged at the side of the collecting system 6, 1 in such manner that this electrode is struck by the beam after the sixth pulse. This results in the electrode I 2 being charged in a negative sense. The negative voltage pulse is transferred by way of a condenser I3 and the conductor 8 to the deflection electrode 5, with the result that the beam in first instance is even further driven onto the electrode l2. After a short time the electrode I2 is charged and the capacity C, which is coupled with the point 9, starts to discharge so that the beam will move in the opposite direction, that is to say in the direction of the collecting system 6, 7.

As soon as the beam leaves the electrode l2, this electrode is discharged by way of a resistance l4, which is attended with a strong positive voltage pulse. This positive pulse is transferred by way of the condenser l3 to the deflection electrode 5, so that the voltage of the point 9 is abruptly increased to a value higher than that of the voltage V5 so that the beam comes within the attraction sphere of the initial position 22 and will move to this position.

In the example here given, the beam thus returns to the initial position after every six pulses.

In order to permit fly-back of the beam after an arbitrarily smaller number of pulses, use is made of a diode I5 which, if desired, may form part of the cathode-ray tube.

The anode of this diode is connected to the point 9, whereas the cathode is connected to a tap on a potentiometer l6, which is connected across the battery II.

The diode becomes conductive if the voltage at the point 9 exceeds the voltage V5 at the tap on the potentiometer. The latter voltage may be varied according to requirements by shifting said tap.

If the beam flies back after having struck the electrode I2, the operation of the diode has the effect of limiting the positive pulse supplied by way of condenser [2 to the deflection electrode 5. Consequently, the voltage at the point 9 cannot in practice exceed the voltage Vs, which is shown by curve 33 in Fig. 2.

After this pulse has ceased, the voltage at the point 9 thus equals V6, which in the example shown lies Within the attraction sphere of the stable position Vs.

What I claim is 1. An electronic circuit comprising a cathoderay tube provided with an electron beam source, a collecting electrode system, deflecting electrodes for deflecting said beam along said system and a reset collecting electrode disposed to be struck by said beam in an extreme position thereof, means coupling said system to one of said deflecting electrodes whereby said beam is adapted to occupy any one of a plurality of naturally stable positions along said system, means for displacing said beam from one stable position to a subsequent position means coupling said reset electrode to one of said deflecting electrodes whereby a pulse derived from said reset electrode displaces said beam to an initial position, a direct voltage source, a rectifier, and voltage adjusting means coupling said one of said deflecting electrodes to said voltage source through said rectifier.

2. An arrangement, as set forth in claim 1, wherein said rectifier is constituted by a diode having an anode and a cathode, and said voltage adjusting means is constituted by a potentiometer having a movable tap, the potentiometer being connected across said voltage source, said cathode being connected to said tap and said anode being connected to said one of said deflecting electrodes.

3. An electronic counting circuit comprising a cathode-ray tube provided with an electron beam source, first and second deflecting electrodes for deflecting said beam, first and second spaced collecting electrodes disposed in the path of the defiected beam and a reset collecting electrode disposed adjacent one end of said first collecting electrode, 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 electrode, means connecting said first collecting electrode to said first deflecting electrode whereby said beam is adapted to occupy any one of a plurality of naturally stable positions along said collecting electrodes, means to apply an external voltage impulse to said second deflecting electrode to displace said beam from one stable position to another, a rectifier, means coupling said reset electrode to said first deflecting electrode whereby a pulse derived from said reset electrodes displaces said beam to an initial position, and means to apply a voltage of adjustable magnitude to said reset electrode through said rectifier.

4. An electronic counting circuit comprising a cathode-ray tube provided with an electron beam source having a cathode, first and second deflecting electrodes for deflecting said beam, first and second spaced collecting electrodes disposed in the path of the deflected beam and a reset collecting electrode disposed adjacent one end of said first collecting electrode, first and second resistances, a direct voltage source having its negative terminal connected to said cathode and its positive terminal connected to said second collecting electrode and through said first resistance to said first collecting electrode, said positive terminal being also connected through said second resistance to said reset electrode, means connecting said first collecting electrode to said first deflecting electrode whereby said beam is adapted to occupy any one of a plurality of naturally stable positions along said collecting electrodes, means to apply an external voltage impulse to said second deflecting electrode to displace said beam from one stable position to another, means coupling said reset electrode to said first deflecting electrode whereby a pulse derived from said reset electrode displaces said beam to an initial position, a potentiometer having a tap and connected across said source, and a rectifier connected between said first deflecting electrode and the tap on said potentiometer.

5. An arrangement, as set forth in claim 4, 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 openings through which said beam impinges on said first collecting electrode.

GERARD HEPP References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,224,677 Hanscom Dec. 10, 1940 2,446,945 Morton et al Aug. 10, 1948 2,463,535 Hecht Mar. 8, 1949 2,477,008 Rosen July 26, 1949 2,498,081 Joel, Jr. et a1 Feb. 21, 1950 2,532,747 Van Gelder et al. Dec. 5, 1950

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