US2608674A - Multicathode glow discharge device - Google Patents

Description

2 SHEETSSHEET l BA me Aug. 26, 1952 w. A. DEPP MULTICATHODE GLOW DISCHARGE DEVICE Filed Feb. 9, 1951 F I6. I C A6 in 20 I 20 20 INVENTOR m A. DE PP BY A T TOR/VEV Patented Aug. 26, 1952 UNITED STATES PATENT orrlcE 2,608,674 lvinn'riori'rnonn GLOW DISCHARGE nnvroa -Wallace A. Depp, Mountainside, N. J assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application February 9; 1951, Serial No. 210,183

Claims.

This invention relates to gaseous discharge devices. and more particularly to multielectrode glow discharge devices of the general type disclosed in theapplication Serial No. 101,322, filed June 1949 of M. A. Townsend, now Patent 2,575,370, granted November 20, 1951. Devices of this type comprise an array of glow cathodes connected electrically in two groups with the cathodes of the two groups in alternate relation, and an anode opposite the cathodes and biased with respect thereto at a positive potential sufficient to sustain a discharge across any cathode-anode gap. I The cathodes of one group may have individual load circuits; connected thereto.

In the operation of the device, a discharge is initiated atone of the cathodes in the one group mentioned and the discharge is stepped along the array by applying signal pulses to the oathodes of the other group to drive these cathodes negative with respect to those of the first group. The discharge is shifted two cathodes for each applied pulse. Thus, the number of cathodes requis'iteforany desired number of output circuits is double this number of circuits.

One general object of this invention is to simplify multicathode gaseous discharge devices of the general type above described. More specifically, one object of this invention is to reduce the number of cathodes necessary. to provide a given number of rest, positions for the discharge or, stated in another Way, to increase the number' of individual output circuits which can be controlled by a device having a given number of cathodes. 'In accordance with one-feature of this invention, in a discharge deviceof the general construction above described, means are provided for applying pulses alternately to the two groups of cathodes to'drive each group negative with respect to the other, whereby to shift the discharge from one cathode to the next in response to one pulse. Each cathode defines a rest position for the'discha-rge so that the number of output circuits which can be utilized or controlled is equal to the number of cathodes. I

' The invention and the above noted and other features-thereof will be understood more clearly and fully from the following detailed description with reference to the accompanying drawing in which:

Fig.1 is a diagram illustrating the principal components and the association thereof in a gaseous discharge device constructed in accordance with this invention;

Fig. 2 illustrates one embodiment of this invention wherein individual relay controlled output circuits are coupled to the several cathodes, and shows one manner in which the signal pulses may be applied to the two groups of cathodes;

Fig. 3 illustrates another embodiment of this invention wherein the cathodes are disposed in circular array, and shows another way in which the signal pulses for stepping may be provided; and

Fig. 4 is a diagram illustrating another em bodiment of this invention, specifically the application of the invention to a binary translator or counter of the general type disclosed in the application Serial No. 168,227, filed June 15, 1950 of A. Townsend.

Referring now to the drawing, the discharge device illustrated in Fig. 1 comprises an enclosing vessel It! having therein anionizable atmosphere, such as a rare gas or mixture of rare gases. Mounted in linear array and equally spaced within the vessel ID are a plurality of glow cathodes H to I5 inclusive. Each of these cathodes, which may be of the constructions disclosed in the application Serial No. 101,322 referred to hereinabove, comprises two portions of difierent efiiciencies as glow discharge sustaining elements the portions of higher efliciency being designated in the drawing by the letter A and the lower efficiency portions by the letter B. As shown in Fig. 1, the cathodes are arranged with the lower effi'ciency portion B of each toward and in juxtaposition to the high efficiency portion of the next preceding cathode, i. e. the cathode to the left in the figure. At one end of the row' of cathodes is a normal or reset cathode l6. Opposite all of the cathodes is an anode H.

The anode H is biased positive with respect to all of the cathodes by a'source 18, through resistor 19, at a potential sufiicient to sustain a discharge between any cathode and the anode. The cathodes H to l5ginclusive, are connected together in two groupswith the cathodes of the two groups inalternate relation each. cathode having in' circuit therewith a resistor 20. Sources 2| andZZ of negative input pulses are connected to the two groups of cathodes respectively as shown. Another source 23 of negative pulses is connected to the normal or reset cathode l6.

Certain principles involved in the operation of the device will be understood from the following considerations. Assume that adischarge is sustaining at one .of the cathodes, say the cathode 12. Because of the cathode construction, the dischargeconcentrates upon the higher efliciency portion thereof, the portion I2A in the case noted. The discharge can be shifted to an adjacent cathode by driving such adjacent cathode sufiiciently more negative, relative to the anode, than the cathode at which the discharge sustains. If two cathodes adjacent the one at which a discharge is sustaining are so driven negative simultaneously, the discharge will transfer to the one of these adjacent cathodes having the lower transfer voltage. As described in detail in the application Serial No. 101,322 referred to hereinabove, the cathode construction and arrangement as in the device disclosed in Fig. 1 hereof provides a preference mechanism whereby stepping of the discharge to a prescribed one of two such adjacent cathodes is effected. Specifically,

for the case here under consideration, that is with the discharge sustaining at cathode l2, if the cathodes II and I3 are driven negative simultaneously, the discharge will shift or step to the cathode I3, the transfer voltage from cathode I2 to cathode I3 being much smaller than that from cathode I2 to cathode II because of the preference mechanism above referred to.

The discharge will stay upon cathode I3 so long as this cathode remains sufficiently negative with respect to the adjacent cathodes I2 and I4, particularly the latter. This condition may be realized by maintaining an appropriate bias upon the cathode I3 for the duration of the period for e which it is desired that the discharge remain at cathode I3. It can be realized also by utilizing negative pulses to eifect the stepping and by making the resistor such that with the discharge sustaining at any cathode, and even aftercessation of the pulse, the voltage drop across the resistor 20 associated with that cathode is less than the transfer voltage between that cathode and the next succeeding one. For example, if the discharge is stepped from cathode I2 to cathode I3 by a negative pulse applied to cathode I3, the discharge will remain at cathode I3 after cessation of the pulse provided that the resistor 20 associated with the cathode I3 is such that the voltage drop thereacross is less than the transfer voltage requisite to step or shift the discharge to cathode l4; 7

The discharge, sustaining at any of the oathodes II to I5, can be transferred to the normal or reset cathode I6 by application of a large negative pulse or bias to the cathode I6.

It will be noted that when the discharge sustains at any of the cathodes II to I5, a voltage appears across the respective resistor 2|]. Such voltage may be utilized to control a respective load or output circuit.

The device illustrated in Fig. 1 may be operated in one way as follows: A negative pulse is applied to'the normal or reset cathode I5 from the source 23 to cause breakdown of the anode II-cathode I6 gap and, thus, establish a discharge thereacross. Then negative pulses are applied alternately to the cathodes I I, I3 and I5 and thecathodesI2 and I4 from thesources 2 I. and 22 respectively. In response, to application ofv the first pulse from the source 2 I, the discharge transfers from cathode I6 to the cathode II, concentrates upon the portion I IA and remains. at this cathode even after the pulse terminates. In response to the first pulse from source 22, the discharge transfers from cathode II to cathode I2 and sustains at the latter. In like manner, in response to successive pulses, applied alternately, from the sources 2| and 22, the discharge steps or transfers from cathode I2 to cathode I3, then from the 4 latter to cathode I4 and finally from cathode Ii to cathode I5. A strong pulse applied to normal or reset cathode I6 will return the discharge to cathode Hi.

It will be noted that the discharge sustains at any cathode to which it is stepped even after the pulse which resulted in the stepping of the discharge thereto terminates. Thus, each of the cathodes I Ito I5 is a rest cathode and utilizable for control of an individual load circuit associated therewith, as through the respective resistor 20. Hence, it will be appreciated that the number of output or load circuits which can be controlled is equal to the number of cathodes, omitting the normal or reset cathode I6. Of course, any such circuit may be controlled by application of a prescribed number of pulses to the device. For example, three pulses, two from the source 2I and one from the source 22 will step the discharge from cathode I6 to cathode I3 and the discharge will sustain at this cathode after termination of the third pulse.

It will be understood, of course, that although the device illustrated on Fig. 1 and described hereinabove includes five rest cathodes, a greater or lesser number of cathodes may be employed.

Fig. 2 illustrates one manner in which the stepping pulses may be applied to the two groups of cathodes, and also in which the load or output circuits may be controlled. As shown, each of the cathodes II to I4 has in circuit therewith a respective relay 25 the contacts 26 of which are to be connected in a load circuit. The anode I1 is biased through a pair of resistors I9 and 21, the resistor 21 being arranged to be short circuited by a switch 28.

Negative signals are applied alternately to the two groups of cathodes l I, I3 and I2, I4 by operation of the two relay switching system 29. The latter, which is of conventional configuration, comprises a'pair of relays 30 and 3| 'connectedas shown with resistors 32 and 33 and to the source 34and having their armatures 36 and 3'! respectively'conn'ected to a ground pulse terminal-'38. Briefly, this system operates as follows: When a ground pulse is applied to terminal 38. relay 30 operates and upon termination of this pulse'relay 3| operates. Operation of the relay 3| causes application of a negative potential from source 39 over armature 40 and contact ll to the cathodes II and I3. When a second ground pulse is applied to terminal 38, relay 30 releases and at the end of this pulse relay 3I releases. Release of relay 3| results in application of a negative potential from source 39 over armature 40 and contact 42 to cathodes l2v and I4. This cycle of operations isrepeated for successive ground pulses applied to the terminal v38. Thus, negative signals are applied alternately to the two groups of cathodes and the discharge is stepped from cathode to cathode in the same manner as described heretofore with reference to Fig. l.

The discharge current during the stepping of the discharge may be limited by the resistors I9 and 21- to a value below that necessary to cause operation of the relays 25 When the discharge has been stopped to a desired cathode, the switch 28 is closed-whereby the discharge current rises to a value sufiicient to operate the relay associated with that cathode. a

The stepping of the discharge by the application of pulses alternately to the two groups of cathodesmay be effected also as illustrated in Fig. 3. As there shown, the device wherein the discharge is stepped comprises a plurality -of cathodes IIU andIZO, which may' be of the same construction as those in the device of Fig. 1, mounted in circular array and connected electrically in twogroups by bus wires 45Jand' 46. Thedevice includes-also the normal orreset cathode I6 and the anode I1. s Stepping pulses are applied alternately to. the two groups of cathodes by pulsing of. a flip-flop gaseous discharge device 50. The latter includes four glowcathodes 5! to 54, which may beof thesameconstruction. as the cathodes I I and I20, and an anode 55 opposite the four cathodes. Each of the cathodes and 52 is connected to a respective group of the cathodes H0 and [23 as shown. The cathodes 5 31 and 54 aresconnected together to a source 50 of pulses for driving these cathodes negative with respect to the cathodes 5| and :52. The latter normallyare biased negative relativeto the'cathodesutfi and 54bythesoui'ce5l.

The operation of the device illustrated inv Fig. 3will-be understood from the following: :A discharge is initiated in the stepping device by-applying-a negative pulse to the normal or reset cathode It, as in the other embodiments ofthis invention-described hereinabove. Similarly, a discharge is initiated in the pulsing device-55 by'applying a negative-pulse tooneoi' the oath: odes 5| or 52. Assume that dischargesare sus taining at' the cathodeEI and thecathode 1H0 nearestreset cathode Hi. When anegative'pulse from the source 56 is applied to the cathodes. 53 and'i'll, the discharge shifts first from cathode 51* to cathode 54 and thenuponcessation of the pulse .tocathode 52. 'As a result, the potential of cathodes: III) will change from negative to positive withrespectto ground and the potential of cathodes I changes from positive to negative with respect to ground. Consequently, the discharge in the stepping device transfers from the cathode III) at which it was initially to the next adjacent cathode I20 in the counterclockwise direction and will rest at the latter cathode. In like manner, each successive pulse from the source 56 causes the discharge in the stepping device to step one cathode in the counter-clockwise direction.

An output pulse may be obtained by way of the normal or reset cathode I6 for each completion of transfer of the discharge around the circular array of the cathodes in the stepping device. Alternatively, individual load circuits may be associated with the cathodes H0 and I20 as in the devices illustrated in Figs. 1 and 2.

The invention may be utilized to particular advantage also in binary translators of the general type disclosed in the application Serial No. 168,227 referred to hereinabove. One illustrative embodiment, shown in Fig. 4, comprises the gasfilled enclosing vessel I0, a normal or reset cathode IB and an anode I1. Mounted in order are preceding cathodes B0 and GI and three rows of cathodes 63, 64 and 65, the number of cathodes 64 being double the number of cathodes 03 and half the number of cathodes 65. Each of the cathodes, similarly to those in the devices shown in Figs. 1, 2 and 3 has two portions of different efficiencies as glow discharge elements and has its lower efliciency portion toward and in juxtaposition to the higher efliciency portion of a preceding cathode. It will be noted that both the cathodes 63 have their lower efiiciency portion in juxtaposition to the cathode BI and their higher efiiciency portion in juxtaposition to the lower efiiciency portions of a respective pair of the cathodes 64. Similarly, each of the cathodes 64 is ccooperatively. associated witha respective pair of the cathodesfifi. The latter constitute the output electrodes of the device. and have indlvidualload. circuits, represented by the re sistors 66, coupled thereto. 2

Because of the construction and relation of the cathodes, itxwillbeappreciated that a discharge sustaining at either of the cathodes 53 may be steppedto either of therespective pair of .cathodes Ei-lv and that a discharge sustaining at any of the cathodes 04 may be trans-@- ferredto eitherof ,therespective pair of. cathodes, E5. lhus, adischarge sustaining at cathode .51 may bestepped to any one of :thecathodes 65 by application of, an; appropriate group. of pulses to thecathodes.

The-:pulse grouping may be in accordance with a binary code and involve permutations of ,0' and l pulses- Forthe eightoutput electrode devices'illustrated in Fig. l, groups of five. pulses areutilized; The permutation, of ,pulses requisite to bring the discharge; to each of-the cathodes 65 is indicated opposite these cathodes in the drawing. The pulses, which are negativeQmay 1 be appliedirorn a'source 6,! over switches. S-|-,

S t, :34 and S- l connected to bus bars. I., 0, I'.- and 0' respectively, which are grounded, as shown, through resistors B8, a'nd connected to theseveral cathodes as shown in. Fig; 4. It will be noted. that in the; device of Fig. 4. as in those illustrated in Figs. l, 2 and 3-, thecathodes are electrically interconnected in groups sothat along arow, alternate cathodes are tied together. and a discharge can be steppedalong such row pp n ne ative p lse al e na e y o l hate cathodes. For; examplaa discharge can be steppedzfrom thexnormal cathode- I G to the lowermost cathode 1 by alternately closing; the switches 3-2 and S 5, thereby to stepthe discharge from cathode it to cathode 60, then to cathode 5|, to lower cathode G3, to lowermost gathode 64 and thence to the lowermost cathode As another example, the discharge may he stepped from cathode It to the output cathode 65 corresponding to code group 00101 in the followmg manner:

Apply pulse to cathode I6 thereby initiating a discharge thereat;

Close S 2 thereby stepping the discharge to cathode 60;

Close S4 and open S2, thereby stepping the discharge to cathode 6|;

Close S1 and open S2, thereby stepping the discharge to upper cathode 63;

Close S4 and open S1, thereby stepping the discharge to next to top cathode 64;

Close S1 and open S4, thereby stepping the discharge to cathode 65 (00101);

Open S1. The discharge remains on cathode 65 (00101).

When a discharge obtains at any of the oathodes 05, a potential appears across the resistor 06 associated with that cathode and this may be utilized as the output signal. This potential is positive with respect to ground and thus is readily distinguishable from the negative potentials which may appear across the resistors during the stepping in response to the pulses applied to the buses 0, 0, I and I. Although some potential may appear across other of the resistors 66 these may be made negligible for practical purposes by making the resistors 68 small in comparison to the resistors 66.

Although specific embodiments of the inven- 7 tion' have been shown and described, it will be understood that they are but illustrative and that various modifications may be made therein without departing from the scope and spirit of this invention.

n What is claimed is: .1.- A gaseous discharge device comprising an array of two groups of cathodes, the cathodes of the two groups being in alternate relation and said cathodes being constructed and arranged to provide a discharge transfer preference from cathode to cathode inv one direction along the array, an anode opposite said cathodes, means biasing said .anode positive with respect to said cathodes at a potential suificient to sustain a discharge between said anode and any of said cathodes, means for establishing a discharge at one of said cathodes, and means for stepping the discharge from cathode to cathode along the array comprising means for applying alternate- 1y to said two groups signals of polarity to drive said groups individually more negative relative to said anode. 2. A gaseous discharge device comprising an array of two groups of cathodes, the cathodes of the two groups being in alternate relation, each of said cathodes having two portions of different efiiciencies as glow discharge elements and said cathodes being disposed with the lower efficiency portion of each injuxtaposition to the higher efliciency portion of the next preceding cathode in the array, an anode oppposite said cathodes, means biasing said anode positive with respect to said cathodes at a potential sufflcient to sustain a discharge-between said anode and any of said cathodes, means for establishing a discharge at one of said cathodes, and means for steppingthe discharge from cathode to cathode along the array comprising means for applying negative signal pulses alternately to the two groups of cathodes.

3. A gaseous discharge device in accordance with claim 2 wherein said pulse applying means comprises a pair of pulse sources each connected between said anode and a respective one of said groups, the device comprising also a resistor individual to and in circuit with each of said cathodes.

4. A gaseous discharge device in accordance with claim 2 wherein said pulse applying means comprises a signal source and means for connecting said source alternately to the two groups of cathodes.

5. A gaseous discharge device comprising a plurality of glow cathodes mounted in an array composed of one cathode followed by a series of rows with the number of cathodes in successive rows increasing by a tractor of two andeach cathode in each but the last row being'in co: operative relation with a respective pair of cathodes in the next succeeding row, there being two cathodes in the first row and saidvone cathode being in juxtaposition thereto, an anode opposite said cathodes, said cathodes defining a plurality of individual paths each extending from said one cathode to a respective cathodein said last row, an anode opposite said cathodes, means biasing said anode relative to said cathodes at a potential suiiicient to sustain a ,dischargebetween said anode and any cathode, means for establishing a discharge at said one cathode,- and means for stepping said discharge selectively along any one of said paths comprising means for applying negative pulses in succession to the successive cathodes defining the one path.

WALLACE A. 'DEPP.

No references cited.

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