US2529233A - Gaseous-discharge device - Google Patents

Description

Nov. 7, 1950 P. w. sTUTsMAN GAsEous DISCHARGE manon Filed June 24, 1947 Patented Nov. 7, 1350 "GAsEoU's-DISCHARGE DEVICE Paul W. Stutsman, Needham, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application June 24, 1947, Serial N0. 756,683

6 Claims. (Cl. Z50-27.5)

This invention relates to gaseous-discharge devices, and more particularly to a cold-cathode gas tube with a collector electrode. Y

An object of this invention is to devise a socalled sub-miniature type bulb with a flat pinch press having a plurality of vitreous insulating sleeves sealed thereinto in order to provide shielding means for a plurality of leads extending into said bulb. I p 'I 1 Another object is to provide a gas-discharge tube having-anelectrode positioned in the path of the discharge between ,the anode and cathode, from which electrode a voltage may be obtained for utilization in a separate circuit, the voltage of said electrode being controllable by said discharge. v

A further object is to provide a cold-cathode gas tube with a collector electrode. v

A still further object is to devise a collectorelectrode type gas tube which will be fired in response to a certain'predetermined voltage difference between its anode and cathode, but will not be iired by a comparable voltage difference between the collector electrode and the cathode.

An additional objectl is to provide a collectorelectrode gas Ytube which will not be iired when either its anode or its cathode is at zero or ground potential, but will be fired when the anode potential and the cathode potential diiIer from' zero in opposite directions by equal predetermined amounts.

The foregoing and other objects of the invention will `be best understood from the following description of an exemplification thereof, reference being had to the accompanying drawing, wherein: I v

- Fig. 1' is a central vertical cross-section, on an enlarged scale, of a gas-discharge tube according to this invention;

Fig. 2 is a horizontal cross-section taken along line 2--2l of Fig. 1;

Fig. 3 is a horizontal cross-sectiontaken along line 3-3 of Fig. 1; y e

Fig. 4 is a partial horizontal cross-section taken along line 4-4 of Fig. l; and

` Fig. 5 is. a diagram illustrating a circuit in which my tube may be utilized. Y

Now referring to the drawing, and particularly to Figs. 1-4 thereof, a .vitreous envelope I of the fiat-bulb type has a flat external pinch press 2 at its lower endand a tipped-0E exhaust tubulation 3 at its upper end. Said envelope is designed to house or contain the electrode structure of the tube of this invention, and is evacuated and supplied with gas through tubulation 3 and thereafter sealed in accordance with the usual practice. Leads 4, 5, 6, and 'I are sealed throughv press 2 and are utilized to convey energy t0 the various electrodes and to assist `in supporting'such electrodes in position inthe envelope. Lead 4 Vis the starting anode lead, lead 5 is the main anode lead; lead E in the collector A electrode lead, and leads] is the cathode` lead, In order to properly shield the leads 4, 5, and Ifrom each other and from the space through which the discharge is intended to take place inside the envelope, three upstanding vitreous insulating sleeves 8, 9, and Ill are provided, each of these sleeves being fused into press 2 at the lower end of such sleeve. Sleeve 8 is concentricl with but spaced from lead 4, sleeve 9 is concentric with but spaced from lead 5, while sleeve III is concentric with but spaced from lead 1. Leads 4, 5, 6, and Tall extend in straight lines, vertically and substantially parallel to each other, as shown. v

Inside bulb or envelope I, near the upper end thereof, there is provided a flattened tubular hollow metallic cathode member or electrode II which is open at its lower end but isv closed at its upper end by a metallic disk member I2 which is welded at its edges to the ycathode I I. Cathode II is of such a size that it substantially lls the interior of envelope I. The upper end of cathode II is held in the center of bulb I by means of a mica spacer I3 which resiliently engages, at portions of the peripherythereof, the inner wall of said bulb and which is fastened to cathode II by any suitable means, for example by a tab I4 integral with the cathode, which tab extends upwardly through an aperture `in spacer AI3 Vand is bent over to firmly engage the top surface offsaid spacer. In order to more firmly support cathode I I in position, a metallic bracket member I5 is wrapped firmly around sleeve |0 near the upper end thereof, and is also welded to the inner wall of cathode II. Sleeve IIJ is terminated immediately above the upper end of bracket I5, and the upper end of lead 'I extends slightly above the upper end of said sleeve. In order to electrically connect-cathode lead 'I to cathode II, a horizontally-extending lead wire I6 is provided, said lead wire .being welded to lead 'I at one end and to the inner wall of cathode II at its opposite end. Hollow iron ywire members II are suitably secured to the inner wall of cathode I-I, near the upper end thereof, these members containing therein an electronemissive material (not shown). Meansv for readily releasing said material is provided by regustructure I9.

Inside bulb I, a substantial distance below cathode II, there is provided a substantially horizontally-extending starting anode electrode As shown in Figs. 2 and 3,- this structure consists of a substantially U-shaped horizontal metallic frame 20 having xed. thereto a metallic wire screen 2I which covers approximately two-thirds of the area of the U, from the base thereof toward the free ends of the legs of the Us VIn order to support starting anode.l9 in position, the free l'endsof the legs of the Uv are attached', as by welding, to the respective opposite ends of a double-ended transversely-extending metallic bracket member 22, the central por-` tion of which is wrapped tightly Yaround sleeve I'.v In order to assist in supporting` starting anode I9, and also to provide el'ectricalconnection thereto, theupperend of startinganode lead 4 is welded to theV centralportion'of 'the base bf the U-frame 29. Y .Avnode electrode 23 is a metallic wire which is secured, as by a. butt-weld, to the upperendcf anode lead 5 and which'extends vertically toa point a. substantial distance below starting electrode ,I9 but somewhat above the upper end of sleeve 9. Y VV Surrounding the upper exposed end of anode 23 isa collector electrode structure generally designated by 24. Structure 24 consists of a hollow metallic tube 25 open at its lower end and having a metallic wire screen 26 extending entirely over its, upper end, said screen being attached to said tube. Tube 25 .is coaxial with anode 23 and sleeve 9, the lower end of said tube tightly engaging the outer surface of sleeve 9 in an area at the upperend of said sleeve. Tube 25 extends upwardly above the upper end of anode 23, so that screen 26` is above the upper end of said anode, but is spaced therefrom by only a rather small distance, on the order of 0.06 inch, for example, while the distance from the upper end of anode 23 to the upper end of sleeve 9 is also rather small, `on the order of 0.04 inch, for example. Therefore, collector electrode'24 is spaced very closey to anode 23, both radially and also longitudinally (by screen 26). ScreenZB, and therefore also collector electrode 24, are positioned in the path of the discharge which can occur between anode 23 and cathode II K In orderv to assist in maintaining collector electrode 24 in position, as well as to provide electrical connection thereto, a metallic bracket member 21, which has arcuate portions at its ends, has Vthe top edge of' one end thereof welded to the lower edge of tube 25; the arcuate end portionsofgsaid bracket member are wrapped tightly around the two sleeves 9 and ID. The

upperend of collector electrode lead' is Welded tothe central portion of bracket member 21 to provide electrical connection to collector electrode 24.

It should be made clear, at this point, that in Fig. 2 the collector electrode structure 24 has not been shown for reasons of clarity, as it is felt that the showing of such structure in the middle of screen 2l in this figure would be confusing. In Fig. 3, the screen 26 has been omitted for the `same reason.

The upper end of sleeve 8 lies in substantially the same horizontal plane as the upper Vend of tube 25. As is shown in Figs; 3 and 4, the longitudinalV axes of leads 4,v 5,:.a'nd 'Land of sleeves 3, 9, and I0, all lie onthefmaorv axis of bulb I, with that of lead 5 and sleeve 9 near the interi section of the major and minor axes of said bulb.

As. may be seen in Figs. 1,3, and 4, both screens 25 and 2I are positioned in the anode-cathode l In gas-discharge' tubespthe total tube voltage Y drop. is made up of the cathode drop, the positive column drop, and the anode drop. In the tube of this -finvention, the collector electrode 24 is spaced from anode 23 a distance approximately `'corresponding to that representing. theA anode drop or anode fall of potential inthe cathodeanode discharge. s

Nowreferring to, Fig. 5, which.V illustrates a circuit invwhich the tube. of this invention could bev used, cathode lII is connected through a resistor 28, having a value on the order of 100,000 ohms', to the movable contact 29 of asingle-pole double-throw switch, one xed contact 30 of which is connected to groundfor a Zero potential point and the other3xed contact. SI' of which is connected to the negative terminal of a source 32 of direct voltage, the positive terminal lof said source being grounded as shown; source 32 may have an electromotive. force of volts, for

example. Y

Starting anode I9 is connected, through a current-limitingresistor v33, to anode 23 and to the movable contact 34 of arsingle-pole doublethrow switch. One xed contact 35 of this lastnamed switch is connected to ground, while theother fixed contact 36 is connected to the positive terminal of a source 31 of direct voltage, the negative terminal of said source being grounded as shown; source 3l may also have an electromotive force' of 100 volts, for example.

Collector electrode 24 is connected through a high resistance'38, on the order of 10 megohms for example, to ground. The collector electrodeV voltage may be abstracted from the tube by leads 39 and 4D and applied thereby to any suitable voltage utilization circuit, suchas in a comput- `ing machine, for example; lead 39 is connected on contact 30 and contact 34 is on contact 35.V

Under these conditions, both kanodes and the cathode are grounded or aty zero potential, so the discharge in the tube is not started.

" If,fn'ow, either contact 29 .is moved to'contactl 3l or' contact 34 is moved to contact 36,Y but not both-either the cathode or the anode will still be at zero potential, 'there will be a potential.

difference of only 100 volts` between starting anode f'l9 and cathode II, and` the` discharge inY the tube will still not be started.

.If both contacts 29 and 34 are moved to theV right (Contact 29 to contact 3| and contact 34 to contact '36), either simultaneously or successively, a voltage of plus 1GO volts is applied to anode 23 andstarting anode I9, and a voltage of minus 100 volts to cathode H. There will then exist the required 200 volts potential difference betweenstarting anode I9 and cathode II; a glow discharge will be initiated between said starting anode and said cathode, causing the main glow discharge between anode 23 and cathode I I to begin, thus firing the tube, since anode 23 has sufcient positive voltage with re-v spect to cathode VII to sustain the discharge. Resistor 33 limits the ilow of current through the starting anode branch circuit when the gaseous discharge is initiated. From the above, it may be seen vthat the tube of this invention is red when and only when its anode voltage and its cathode voltage differ from zero, in'opposite directions, by equal predetermined amounts. This firing, discharge of the tube, or conduction of the tube, is caused to occur independently of the voltage on collector electrode 24, as will be brought out subsequently.

When the cathode-anode discharge begins, the potential of collector electrode 24 rises, substantially instantaneously, to one which is relatively close to that of the anode 23. This rise of potential, in response to conduction in the tube, appears between leads 39 and 40 'and may be utilized in a suitable voltage utilization circuit. It is not necessary to understand exactly why this change of potential occurs, but presumably this rise or increase of positive potential of the collector electrode results from the collection of positive ions by such electrode. The electrode 24 is positioned in the path of the main glow discharge.

It has been found that, for any given gas or mixture of gases in envelope I, the Vparticular collector electrode structure disclosed, consisting of both the solid-walled metal tube 25 and the wire screen 26, gives the closest possible approach to a minimum potential difference between anode 23 and collector 24 during the discharge.

The provision of screen 26 over the end of tube 25, rather than entirely closing the end of said tube, allows the discharge to pass between anode 23 and cathode II through said screen.

It has been found that different gases have different anode falls of potential (which falls are approximately equal to the potential diierence between anode 23 and collector 24 during the discharge, as noted above), and that the various anode falls of potential are of the same order of magnitude as the rst ionization potential of the corresponding gas. With the kryptonxenon mixture described above, it has been found that there will be a potential diierence of approximately volts between anode 23 and collector 24 during the discharge, while with the neon-argon mixture there will be a potential diierence of approximately 20 volts, and with helium a potential difference of approximately 24 volts. Thus, with a neon-argon mixture and with a voltage of 100 volts on anode 23, as above described, the potential of the collector 24 will be approximately plus volts during the discharge.' and'thisrise of potential of said collector from zero to 'approximately 80 volts willr occur substantially simultaneously with the initiation of the cathode-anode discharge.

It has been found that the resistor 38 in series with the collector electrode must have a high value of resistance; if this resistance is made to'o low, the power necessary to hold the collector electrode at a high potential will be beyond the capacity of the tube.

By the inclusion in starting anode I9 of wire mesh or screen, and also by the placing of said starting anode between collector electrode 24 and cathode I I, I have in effect provided a shield between the collector electrode and the cathode. As a result, no discharge will be initiated even if the collector 24 has a potential comparable to that at which the starting anode would cause the tube to rire, as long as the anode has a potential less than its required starting potential. In other words, the collector is not capable of starting the discharge at a voltage equal to that at which the starting anode would cause a discharge to occur. The tube will not conduct, Vin the vexample given, if Vthere is a potential of zero or plus volts on the collector, if the voltage on either the anode or the cathode is zero, but thev tube will conduct, independent of the voltage on the collector, if there is plus 100 volts on the anode and minus 100 volts on the cathode. Thus, premature or improper firing of the tube is prevented.

'At' this point, it is desired to be brought out that the tube of this invention is extremely small in size. For example, in a tube constructed according to this invention, the major external diameter of the bulb was approximately 0.36 inch, the minor external diameter was approximately 0.3125 inch, while the overall length of the bulb (from the bottom of press 2 to the top of tubulation 3) was approximately 11/2 inches.

Sleeves B, 9, and I0, which are vitreous or madeV of insulating material, are for the purpose of shielding the lead wires which they respectively surround, so as to prevent discharges occurring between portions of the electrodes where such discharges are not desired, or in regions of the space where discharges are n'ot desired or where, if they occurred, they would interfere with proper functioning or operation of the device.

Of course, it is to be understood that this invention is not limited to the particular details as described above, as many equivalents will suggest themselves to those skilled in the art. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of this invention within the art.

What is claimed is:

1. A gaseous discharge device comprising an envelope containing an ionizable gas, a metallic cathode and anode inside said envelope spaced from said cathode to provide a path therebetween in which a glow discharge may be established, means for establishing a glow discharge between said cathode and said anode, and a collector electrode positioned in said path at a distance from said anode substantially equal to that corresponding to the anode fall of potential of said glow discharge.

2. A gaseous discharge device, comprising an envelope containing an ionizable gas, a metallic cathode, a main anode inside said envelope spaced from said cathode to provide a path therebetween in which a glow discharge may be established, a

amazes; `Y

electrode being caused to assume;apositivepotential-with'frespect to *said cathode by theestab-f,

lishrnentof'saide` glow discharge; andastarting anode positioned adjacent said cathode: between said electrode and: said cathodexto, establish said glow'discharge, said starting anode having a perforatedaportion extending j across the :discharge path between said cathodeand electrode and intercepting all straight line discharge pathsY therebetween to shield said cathode from said electrode,;thereby to prevent establishment of said glowdischarge by said electrode.

l 3. A gaseous discharge device, comprising an envelope containing an ionizable gas, a metallic cathode and. anode inside said envelope spaced from said cathode to provide a path therebetween in which a gl'ow discharge may be established, a collectorelectrode positioned in said path at adistance from said anodeV substantially equal to that corresponding to the anode fall of potential ofsai'd discharge, and a perforated shielding elec-I trode intercepting all'straightline paths between saidcathode and' said electrode for shielding said cathode from said electrode, thereby to prevent establishment of saidrglow discharge by said elec- 4. A gaseous discharge device, comprising an envelope containing an ionizable gas, a metallic cathode, a wire main anode inside said envelope spaced from said cathode to provide a path therebetween in which a glow discharge maybe established, a collector electrode positioned in said path at a distance ,from saidan'ode substantially edual to that corresponding tothe anode fallof potential ofsaid'discharge; anda starting anode positioned adjacent said cathode'to establish said glow discharge.

'52 A gaseous discharge device, comprising "an envelope containing an ionizable gas, a metallic cathode, a main anode inside said envelope spaced from said cathode to provide a path therebetweenV inwhich a glow discharge may be established, a collector electrode` positioned in said path at a distance' from said anode substantially equal to that corresponding to theA anode fall ofpotental of said'dischargaanda starting anode positionedl adjacent said;cathode betweenzsaid electrodeand said cathode toest'ablish saidglow discharge, said starting" anode having a perforated portionxextending. across theA discharge -path between; saidzV cathode and' electrode andV intercepting all straight lineA discharge paths therebetween'to shield said cathode from Said electrode, thereby` to prevent establishmentlof said glow dischargeby said electrode. f

6. A.. gaseous discharge device, comprising a.:

glass envelopey containing an ionizable gas,V a,

metallic cathode, a wire'anode inside said en.-v

velope spaced from said cathode to'provide a path therebetweenY in which "a glow discharge maybe;

established, va collector-electrode positionediinf said path at a distance from said anode sube'.

stantially 'equal to that corresponding to the anode fall-of :potentialof saiddischarge, and a perforated shielding lelectrode* "fintcrceptingf alli straight line paths between said cathodeandLsaid" electrode for shielding said cathode .iromlsaid7 electrode,thereby to prevent establishment ofisaid' giov/discharge by said electrode, vsaid cathoda;

anode, collector electrode, and shielding electrode having lead-in wires sealed through one end of:

" *nare-names CITED v The fourmngM le of this patent:

v UNITED STATES PATENTSv Number Narnle Date 1,939,063 Knowles Dec. l2, 1933 2,053,501 Spencer Sept. 8, 1936 2,106,847 Knipekarnp Feb.v l, 1938 2,435,246 Stutsman Feb. 3, 1948 V'PAUL w. sTUTsMAN.

references are of record in the'V

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