US2532747A - Circuit arrangement comprising a cathode-ray tube - Google Patents

Description

Dec. 5, 1950 2. VAN GELDER ETAL 2,532,747

CIRCUIT-ARRANGEMENT COMPRISING A CATHODE-RA Y TUBE Filed Feb. 11, 1949 I N VEN TORS ZEGER VAN'GELDER ADRIANUS J. W.M. VAN OVERBEEK BY 7 AGENT Patented Dec. 5, 1950 STATES PATENT OFFICE CIR U GE OM I G CATHODE-RAY ,TUBE

-Zeger van Gelder and Adrianus Johannes Wil- -helmus lvlarie van overbeek, Eindhoven,=-Netherlands assignors to Hartford National Bank a and Trust Company, Hartford, Conn; astrustee Application February 11, 1949,;Serial No. 15,916

"In the Netherlands March 16, 1948 54 Claims. 1 'ii'lhe invention *relatesto a circuit-arrangement rncludi-ngtacathode-ray tube comprising means tor ideflectingthe: cathode ray beam, said I tube .ofgcathodeeray tubes comprising a. group of collcctin ielectrodeseach of which may beprovided with itsqzowmoutput circuit. ,If the cathode-ray beam scans these collecting electrodes with a constant angular speed in .succession,.,difierent c nnections areestablished. This has a limitaition-in that between the scanning of two collect ing electrodes some period of,time elapses use- ;lessly. In orderto reduce this period, the distanceabetweenthese collecting electrodes may be made: smaller but this entails the necessity ;of usinga-beam of small section so that the current strength of z the beam is relatively low.

If thecathode-ray tube comprises, in known mariner thelabove further collecting electrode, whichconsequently is struckiby the beam every time. between, the scanning of each pair of successive collecting electrodes of the group, the circuit arrangement according to the invention permits offobviating the above disadvantages.

IIhe circuitarrangement according to the inyjentio'nf'exhibits thefeature that the deflecting means are coupled to the further collecting electrode in suchmanner that, owing to this coupling, at a deflection of the cathode-ray beam effected perse with the use of 'thedeflecting means with substantiallyconstant angular speed the angular speed "of "the beam during impingement on the further'collecting electrode difiers' from the angular speed-f the beam during impingement on the collectingelectrodes of the group.

-Sta-rting with -a deflection voltage or current which-imparts a constant or substantially constant'anguiar speed to the cathode-ray beam, the

"coupling between the deflecting means and the further collecting electrode consequently ensures that the'angula'r speed of the beam during-impingement-one collecting electrode of the system difiers-from-that speed during impingement onthe further collectingeleotrode.

:kIn order thatthe invention-may be more clearly understood and readily carried into effect, itwill now be described-more fullywithreference to the accompanyingmdrawing inwhich Fig. l -shows-an embodiment of the circuitarrangement according to the invention, the operation of which will be set out with reference to Fig. 2 and fFigp3 'showsan alternativeembodiment of the 'circuit arrangement according to the invention.

:The. cathode-ray tubel iir Fig. 1, i which comprises. means for producing a cathode-ray beam 2=u(shown idiagrammatically) contains deflectin platesi3 and l. The tubefurthermore comprises agroupof collecting electrodes of which four, numbered- '5 to'8, are shown. .These electrodes, each ofuwhich is. provided with. its own voutput circuit, have arrangedbehind them a further collecting "electrodeizfl which. is, connected. by way ofg-a resistance lfl'to, a voltagexsource. The. lefthand deflecting p1ate53 is connected througha resistance I l 1tov the positive terminal l2.,,of,-a battery; the other end of :which is earthed. In the present case the terminal voltage of this battery is chosen to be. such, forexample, that the beam precisely, strikes the left-hand, collecting electrode 5 of thegrou if the right-hand deflecting plate 4 hasearth potential. If the right-hand deflecting plate has applied to it through a resistance l3 a sawtooth voltage produced by a generator Hi, the beam will move to the right with a substantially constantangular speed during the time thesawtooth voltage increases linearly or substantially linearly. The beam consequently moves away from the electrode 5, passes through the first-aperture 15 on to the further collecting electrode 9, then strikes the next following. collee-ting! electrode. 6 of the group, subsequently again impinges on the collecting electrode 9,'and so forth.

If the time during which the beam. strikesone of the collecting electro'desfi to'8jis usedjfor example, for communication purposes, the time during which the beam falls between the collect- 'ing electrodes is to be looked upon as a loss.

In order to re'duce'this loss of time, the further electrode!) is coupled by way'of acondenser; IE to the deflecting plate 3.

- When inthese circumstances the beam moves from the-collecting electrode 5 to the collecting electrode 5, the voltage drop occurring "across resistance'lil in the supply conductor of the further collecting electrode Swill be passed on to the deflecting plate-3. This voltage drop across the plate 3 shows itself in the total efiective deflecting voltage as a voltage increase with the result that the rate atwhich the beam is-displaced' is increased.

-if thebeam then stifilxes-the-cbllectin'g electrode- 6 the positiom of-=thebeam-wi11 againxbe substantially determined by the deflecting voltage produced by the generator I4.

In Fig. 2 the deflection angle a. of the beam, measured from the left-hand side of the electrode 5 in Fig. 1, is plotted as a function of the time t.

The positions of the electrodes 5 to 8 cor responding to definite deflection intervals are plotted in Fig. 2 along the ordinate in thicl; lines. The deflecting voltage produced by the generator [4, which increases substantially linearly and consequently corresponds to a substantially linear relationship between the deflection u. and the time t, is indicated by a straight line ll. If there is no coupling between the further collecting electrode 9 and the'deflecting plate 3 and if the extension of the collecting electrodes 5 to 8 in the direction of deflection is, for example equal to that of the intermediate spaces, the cathode-ray beam moves from i= to t=t1 over the electrode 5, then for an equal period of time from t=t1 to t=t2 over the intermediate space 15, and so forth.

However, if the coupling is made with the use of condenser 66, the angle a increases linearly with time during the impingement on the collecting electrode, that is to say during the period from t=to to t tl but the voltage across the deflecting plate 3 is decreased during the impinge ment on the further collecting electrode 9 and thus the total eirective deflecting voltage is increased, as indicated by the curved part it? in Fig. 2. Thus, the beam does not strike the collecting electrode 8 at an instant is, as would be the case if the coupling were not provided, but at a prior instant t5 and then during impingement on the electrode 6 moves again with a substantially constant angular speed. The ineflective period from 151 to t2 is thus materially restricted and reduced to the period from 151 to its.

' It should be noted here that the variation of the deflecting voltage as a function of time, after a subsequent electrode is struck, for example the form of the part lSa of the curve in Fig. 2, de-

pends on the time constant of the deflecting system together with the condenser l6 and a capacity 160. that may be connected in parallel with the resistance 1 I and, for example, is slightly variable by varying or providing capacity 560..

Obviously the substantially linear deflecting ment shown in Fig. l, which only differs in that .1

the further collecting electrode is is arranged in front of the group of collecting electrodes 20, 2| and 22 and exhibits suitably chosen apertures 23, 24 and so forth to allow the passage of the cathode beam.

It should furthermore be noted that if it is desirable that the beam should move rapidly over the group of collecting electrodes and slowly during the intervals, this may be achieved, for example, by connecting in Fig. 1, the further collect:

Owing to the time coning electrode 9 to the deflecting electrode 4 instead of connecting it to the deflecting electrode 3.

As an alternative, a similar effect may be achieved by realizing the further collecting electrode Q or E9 of the circuit-arrangement shown in Fig. 1 or 3 respectively as a secondary emission electrode. Owing to the resulting secondary emission of electrons, with a secondary emission factor 5 1, the voltage across the supply resistance I0 or 25 respectively will increase during impingement of the beam on this electrode. This increase in voltage is passed on to the deflecting plate and shows itself as a decrease of the total effective deflecting voltage with the result that the speed of the beam is reduced.

What we claim is: I

1. An electrical circuit arrangement, comprising a discharge tube having a source of an electron beam, a plurality of collecting electrodes spaced apart and spaced from said source, means to deflect said beam and an electrode member having conductive portions arranged in the path of said beam between the spacings of said collecting electrodes, means to apply a signal of given phase to said deflecting means to deflect said beam in a given direction and with a given velocity thereby to cause said beam to impinge successively on said collecting electrodes and said conductive portions, and means to accelerate the deflection of said beam between adjacent of said collecting electrodes comprising an impedance element intercoupling said electrode member and said deflecting means and applying an auxiliary signal voltage to said deflecting means in the same phase as said given phase.

2. An electrical circuit arrangement, comprising a discharge tube having a source of an electron beam, a plurality of collecting electrodes spaced apart and spaced from said source, a pair of deflecting electrodes arranged to deflect said beam and an electrode member having conductive portions arranged in the path of said beam between the spacing of said collecting electrodes, means to apply a signal of given phase to said deflecting electrodes to deflect said beam in a given direction and with a given velocity thereby to cause said beam to impinge successively on said collecting electrodes and said conductive portions, and means to accelerate the deflection of said beam between adjacent of said collecting elec trodes comprising an impedance element intercoupling said electrode member and one of said deflecting electrodes and applying an auxiliary signal voltage to said one deflecting electrode in the same phase as said given phase.

3. An electrical circuit arrangement, comprising a discharge tube having a source of an electron beam, a plurality of collecting electrodes spaced apart and spaced from said source, a pair of deflecting electrodes arranged to deflect said beam an an electrode member having conductive portions arranged in the path of said beam between the spacing of said collecting electrodes, means to apply a signal voltage varying substantially linearly with time and having a given phase to said deflecting electrodes to deflect said beam in a given direction and with a given velocity thereby to cause said beam to impinge successively on said collecting electrode and said conductive portions, and means to accelerate the deflection of said beam between adjacent of said collecting electrodes comprising a capacitive ele-:- ment intercoupling said electrode member andone of said deflecting electrodes andapplying an auxiliary signal voltage to said one deflecting electrode in the same phase as said given phase.

4. An electrical circuit arrangement, comprising a discharge tube having a source of an electron beam, a plurality of collecting electrodes spaced apart and spaced from said source, means to deflect said beam and an electrode member having conductive portions comprising secondary electron emissive surfaces arranged in the path of said beam between the spacing of said collecting electrodes, means to apply a signal of given phase to said deflecting means to deflect said beam in a given direction and with a given velocity thereby to cause said beam to impinge successively on said collecting electrodes and said conductive portions, and means to accelerate the deflection of said beam between adjacent of said collecting electrodes comprising an impedance .6 element intercoupling said electrode member and said deflecting means and applying an auxiliary signal voltage to said deflecting means in the same phase as said given phase.

ZEGER VAN GELDER.

ADRIANUS JOHANNES WILI-IELMUS MARIE VAN OVERBEEK.

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

UNITED STATES PATENTS Number Name Date 2,250,528 Gray July 29, 1941 2,417,450 Sears Mar. 18, 1947 2,477,008 Rosen July 26, 1949

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