US2607015A

US2607015A - Multicathode glow discharge device

Info

Publication number: US2607015A
Application number: US202284A
Authority: US
Inventors: Mark A Townsend
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1950-12-22
Filing date: 1950-12-22
Publication date: 1952-08-12
Anticipated expiration: 1969-08-12

Description

1952 M. A. TOWNSEND MULTICATHODE GLOW DISCHARGE DEVICE Filed Dec. 22, 1950 FIG. 3

IN VE/V 70/? A. TOWNSEND A T TORNEV Patented Aug. 12, 1952 MULTICATHODE GLOW DISCHARGE DEVICE Mark Townsend, Berkeley: Heights, N. J assignor to Bell Telephone'Lahoratories, Incorporated, New York, N. Y., acorporation of New York . Application December 22, 1950, serial No. 202,284

,disclosed in. the application Serial No. 101,322

filed-June 25, 1949 of M. A. Townsend, now Patent 2,575,370, granted November 20, 1951.

Devices of the type disclosed in the above-identified application comprise, in general, two groups of cathodes mounted in alternate relation and in cooperative relation with a common anode. The several cathodes are constructed and arranged to provide what has been termed a preference mechanism whereby in response to directcurrent signal pulses applied between the two groups of cathodes the discharge is stepped or shifted in one direction from one cathode-anode gap to the next adjacent one, the number of steps being in accordance with the number of pulses applied.

One general object of this invention is to improve gaseous discharge devices of the type above described. More specific objects of this invention are to enable stepping of the discharge from cathode to cathode in such devices, directly in accordance with alternating-current signals, and to simplify the structure of multicathode, glow discharge, stepping and counting devices. I In one illustrative embodiment of this invention, a discharge device comprises anarray of electrodes each capable of .acting'as a glow. cathode. Each electrode is ,constructed'to havetwo portions ofdifierent efficiencies as glow discharge sustaining elements and the several electrodes are mounted with the portion of higher efficiency of each in juxtaposition to the lower efficiency portion of a next adjacent electrode. An output circuit may be connected to one or more of the electrodes or a plurality of output circuits may be connected individually to severalrespe'ctive electrodes;

In accordance with one feature of this invention, the electrodes in the array are'electrically grouped and energized in accordance with alterhating-current signals so that each electrode acts alternately'as a cathode and an anode, whereby in response to such signals a discharge, sustaining between any two adjacent electrodes, is stepped along the array, advancing two gaps for each cycle of the applied signals;

More specifically, in accordance with one feature of this invention, alternate electrodes are connected electrically in two groups and the alternating-current input signals, of amplitude sufficient to sustain a discharge between adjacent electrodes; rem in d be are 'PW een Claims. (Cl. 313-188) The invention'and the above-noted and other features thereof will be understood more clearly and fully fromthe following detailed description with reference to the accompanying drawing in which:

Fig. 1' is in part a diagram and in part a circuit schematic illustrating the principal elements and the organization thereof in a gaseous discharge device constructed in accordance with this invention;

Fig. 2 is a diagram showing a multistage discharge device illustrative of one embodiment of this invention, wherein a plurality of output circuits individual to alternate electrodes are provided; and

Fig. 3 is a perspective viewshowing details of construction of a discharge device illiis'trative'of this invention.

, Referring now to the drawing, the discharge deviceillustr-ated in Figs. 1 and ,2 comprises an enclosing vessel It having therein an ionizable atmosphere, such as a rare gas or a mixture of rare gases.' Mounted within the vessel is'a group of electrodes HA, H3 and HC each of which has a hollow or channel-shaped portion 2, a tail portion [3 anda stem or support portion, 1 4. The several cathodes constituting this group are con- 'nected together electrically by aftie wire 'I 5. Also "mounted within the vessel and in alignment and in alternate relation with the electrodes l I are a plurality of electrodes .lG'A, NE and [60. Each of the electrodes l6, likev the electrodes ll, includes a hollow or channel-shaped portion, a tail portion and a stem or support portion. The electrodes 16 "are connected together electrically by a tie wire l'l.

The electrodes H and'lG advantageously are formed'of sheet refractory metal, suchas molybdenum or tantalum. As shown clearly in Fig. 1, each of the electrodes It is mounted with its hollow' or channel-shaped portion in juxtaposition to the tail portion tothe next succeeding. electrode I l. and with its own tail in juxtaposition to the hollow or channel-shaped portion of the next preceding electrode ll. When a discharge sustains at any of the electrodes, the discharge will concentrate and highest ionization will obtain at the channel-shaped portion of that electrode the respective resistor.

sustaining at electrode HB and the electrodes I6 are pulsed positive relative to the electrodes H the tail portion of the electrode 16B will be adjacent a region of high ionization density whereas the electrode [6A will be adjacent a region of low ionization density. Consequently, the discharge will beshifted'from electrode 1 M3 to electrode ISB rather than in the opposite direction. Thus, by virtue of the preference mechanism noted, stepping or shifting of the discharge occurs to the right in Fig. 1.

Adjacent the electrode I [A is an auxiliary electrode [8 which may be connected to a pulse source not shown by way of resistor 22. The electrodes l6 are connected to a source of alternating-current input signals through series connected resistors l9 and 28 having associated therewith a condenser 21 as shown.

In the operation of the device, a positive starter pulse, indicated at P1, is .applied to the auxiliary electrode l8'whereby a discharge is initiated between the electrodes HA and I8, the electrode HA acting asa cathode. On the first positive 'half cycle of the input signal, indicated at P2, a discharge is established between electrodes HA and 16A with the electrode l IA acting as a cathode and the electrode 16A asan anode. On the succeeding negative half cycl of the inputsignal the polarity of the electrode relative to the electrodes II is reversed and breakdown occurs to the electrode ISA acting as a cathode. At first because of residual ionization from the first positive half cycle of the input signal, electrode HA will act as an anode. However, because of the construction of the electrode I 6A as above described, ionization will be high or intense in the region between the electrodes 16A and HB and the discharge obtains between electrode |6A acting'as a cathode and electrode HB acting as an anode. .On the next succeeding positive half cycle of the input signal, electrode IEA becomes an anode and'electrode HB acts as a cathode. On the next succeeding negative half cycle of themput signal electrode 1 IB becomes the cathode and electrode 16B functions as an anode.

Thus for each half cycle of the input signal the discharge is moved one position along the row of "electrodes advancing in effect from one cathode to the next succeeding one.

Although in the construction illustrated in Fig. '2 six discharge sustaining electrodes are shown, it will be understood, or" course, that a greater number may be employed. For example, as shown in Fig- 1, the device may comprise twenty such electrodes and be capable of counting ten complete. or twenty half cycles. Each of the electrodes l I may have associated therewith a suitable output'or indicating circuit indicated generally by resistors 23 whereby when a discharge sustains at any of these electrodes a pulse is produced across These pulses may be recorded; for example in' the manner described in the 3 application of M. A. Townsend heretofore identified.

ltwi'llibe-understood, of course, that theinput signal "should be of amplitude sufiicient to sustain --spective tie rings l5 and I1.

4 nal. Specifically, the parameters of these impedances are correlated so that with a neon filled tube a delay of the order of 50 to 200 microseconds occurs in the process of reversing the voltage across the tube. The delay must of course be less than the deionization time of the gas involved.

One physical embodiment ofa discharge device constructed in accordance with this invention is illustrated in Fig. 3. As there shown, the several electrodes H and 16 in alternate relation 'aremounted'in a circle, the electrodes 1 I and electrodes 16 being interconnected electrically by re- These tie rings in turnare connected to leading-in conductors 24, in turn connected to terminal prongs 25 upon a base 26 to which the enclosing vessel H1 is afiixed. .It will beunderstood, of course, that if in the device illustrated in Fig. 3 individual outputs for the several electrodes l8 are desired, respective leading-in conductors for these lectrodes will be provided as in themanner indicated in Fig. 2.

Itwil-l be appreciated that inasmuch as in the device illustrated in Fig. 3 the several electrodes l i and I6 are mounted in circular array, frequency dividing maybe btained one output pulse being realized at one-electrode for each ten complete cycles of an alternating-current input signal.

Although specific embodiments of this invention 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 in- 'vention.

What is claimed is:

l. A gaseous discharge device comprising an array of similar electrodes each capable of functioning as a glow cathode, means electrically connecting said electrodes in two groupswith the electrodes of the two groups in alternate relation, said electrodes including'means'defining a directional preference mechanism, and means for impressing between said two groups alternatingother alternate electrodes alternately positive and negative relative to said one group sufficientlyto sustain a discharge between adjacent electrodes.

3. A gaseous dischargedevice in accordance with .claim.2 comprising load circuits individual to the electrodes in said one group.

4. A gaseous discharge device comprising a plurality of refractory metal electrodes each having a channel portion and a tail portion, said electrodes being mounted in a row with the channel portion of each adjacent the tail portion of the next succeeding electrode, means electrically connecting said electrodes in two groups with the electrodes of the; two groups in alternate relation, and means for impressing between said two groups alternating-current signals of amplitude sufiicient tosustain a glow dischargebetween any two adjacent electrodes.

'5.A gaseous discharge device comprising a plurality ofrefractommetal electrodes each having trode, and means for stepping the discharge along 10 Number said row comprising means for applying alternating-current signals between said two groups.

MARK A. TOWNSEND.

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

UNITED STATES PATENTS Name Date 2,524,213 Wales Oct. 3, 1950