US2603758A - Ultrahigh-frequency triode - Google Patents

Description

D. W. POWER ULiTRAHIGH-FREQUENCY TRIODE Filed on. 26, 1946 July 15, 19 52 Patented July 15, 1952 ULTRAHIGH-FREQUENCY TRIODE Donnell W. Power, New Providence, N. J., assig'nor to Radio Corporation of America, a corporation of Delaware Applicationctober26, 1946, Serial No. 705,951

llClaims. or. 313-252) The present. invention relates to electron disa charge devices, and more particularly to electron discharge devices useful at ultra high frequen-- cies, and to a method of manufacture .andassembly of such devices. 7

Electron discharge devices designed for ultra high frequency operation aremore limited as to structure than devices foruse atlower frequencies. I For example, the electrode elements in an ultra high frequency electron discharge device must observe closer tolerances in spacings relative to each other and must maintain such critical spacings during operation of the device. In

:addition the electrode leads for such devices must be characterized by critical dimensions and spacings to avoid undesired capacity effects therebetween. Although these factors require recog- 'nition,.to a lesser or greater extent, in all types of electron discharge devices they become more critical as the frequency at which the devices operate is increased. .These structural limitations present obvious problems in the manufacture of such devices, particularly by mass production methods. One ofthe problems concerns the selection of the most desirable type of electrode elements. Thus,

.in some types of electron discharge devices useful at ultra high frequencies, planar type electrodeelementshave been utilized; for example,

in triodes: a flat grid is interposed between a flatsurfaced cathode and a flat surfaced anode, both closely. spaced from the grid. In other types ofsuch devices. concentric electrode elements have been proposed. In certain respects concentric electrode elements are more advantageous than planar. electrodes. :For example, less heater power is required for devices using concentric electrodes than for those having planar electrodes, since in the former heat in. all radial directions is utilized for producing electron emission whereas in the latter the heat in one plane only is made use of for thispurpose. Furthermore, it is possible to more effectively maintain the desired alignmentand spacing of concentric electrode elements during operation, once these have been fixed in manufacture, for the reason effects between leads to the input and output electrodes of an ultra high frequency electron discharge device, they should be as short as 'posthe structure of the I improved electron discharge device tra high frequencies; v

. 2' sible and spaced from each other as far as possible. This has resulted in the practice of taking the leads from spaced apart locations on the device envelope. One expedient" has been to make these leads integral with the envelope,,one lead being contributed by an end portion of the envelope and the other lead being formed by a disc sealed through the envelope well. 'However, this arrangement is accompanied by the danger that unless-the disc is sealed to the envelope prior to the fixing of the electrodes'therein, the greater quantity of heat'required for the larger disc envelope seal will harmfully affect the mounting of the electrodes, and any other seals previously made in assembling the device. It is, therefore, desirable in the manufacture of the device that the steps followed in assemblybe characterized by a descending order of heat quantity required therein to safeguard the seals produced by such heat.

Another matter that requires consideration in the manufacture of an electron discharge device placement of the electrodes in the envelope'of the device prior to effecting the various seals for com'pletingthe envelope, there is danger that the heat required for such seals might harmfully oxidize the previously sprayed electrodes. It is obviously desirable therefore, that the manufacturing procedure involve completion of the seal for forming the envelope prior to insertion -of the electrodes therein. 1 I

It is an object of my invention to provide an useful at ul- Another object of my invention is to provide 7 a structure for and a method of assembling an that heat produced during operation affects conelectron discharge device which will facilitate assembly. and insure good seals.

A .furtherobject" is to provide a method of fabricating. electron dischargedevices useful at ultra high frequencies in which spacing of the electrode. elements is determined in a positive manner. by elements previously assembled and sealed. "f

.An additional object is to provide a methodof making anelectron discharge device useful at ultra high frequencies, having-hollow electrodes which-follow 'an order in manufacture assuring good seals and aminimum oxidation of the electrodes thereof Another object is to provide a method of makingan electrondischarge device from previously prepared parts formed :to permit the .use. 'ofcendrawings which show embodiments of'm'y inven tion for purposes of illustration only and not by velope and disc [6 with opposite ends of the envelope open for subsequent insertion and mounting of the electrodes therein. This completes the larger seals I1, I 8, l9 and 25! before the other seals, closing the ends of the envelope and requiring a lesser quantity of heat, are made. This feature-permits the use of disc 18 as an electrode way of limitation, in which:

,Figure 1 shows a triode, in section, made-ac.- cording to my novel method wherein the anode is supported in the central aperture of 'the'disc' '15 lead-in conductor, the electrodes and'envelo'pe being cylindrical;

Figure 2 is an exploded View; partly in section;

. impair other seals of the device.

also provides for insertion'of the electrodes with' in the'envelopeafter the larger seals have been support'and as a-lead-infconductor without danger that the sealing thereof to the envelope might This feature completed, thus preventing oxidation of the elecof the relationship of the parts employed in my novel method of fabricating the ultra high ire-' fication wherein the chambersfor passagewaysin V the end portions offthe envelope are formed by tapered walls and the centering pin is-p'rovided Within certain longitudinal sections of tapered elevation.

Referring now to the drawing in more detail, there is shown in Figure l an ultrahigh fre quencyt'riode made in accordance'with the meth od ofm'y invention which includes an envelope and electrodes mounted therein. The envelope includes a tubular metallic flanged end section I a tubular glass section 2, a second tubular glass section 3 and a tubular metallic flanged end sectionA. Each of these envelope sections defines an open-ended chamber or passageway. electrodes, which in thisem-bodiment are cylind-ric'al in shape, comprise an anode 5, a cathode *6, 'ahda grid 1, which are concentrically: disposed and have equal lengths. Supports are prov'ided for each of the electrodes.

Cathode support 8 has a hollow interior affording accommodations for cathode heater leads 9 and getter 10. This support 8 is mounted with a portion thereof in snug engagement with -'-the The trodes by the heat-required for such larger seals.

'Ar'io'ther feature of the invention is the pro- 7 vision of previously prepared parts for forming the envelope and. the electrode assembly, which are correlated in shape and dimensions to a cent'e'ring'and spacing means employed in the manufacture of the device. -This feature of the invcntion requires that the parts for forming the envelope sidewall be first assembled and sealed, leaving end portions open for insertion of.elec trodes and their-supports into the envelope in predetermined locations for forming snug fits'between-the electrode supports and interior. wall portions-of the envelope j;-;' r The open ended-chambers or passageways 34., 36 in fi'ar'ed e'nd sections '4 and |,.shown in Figure '2, have dimensions for receiving in snugfits portion 12d 'of grid support I2 'andp'ortion 'Baof cathode support 8, respectively. The end chambore '34, 35 are accurately aligned axiallyby a jig orcentering pin to be described. The grid land cathode 6 are also accurately"alignedaaxiallyswith respect to their supports l2 and 8,: which. alignment may be "accomplishedin themannershown inFigu're '4. As will bemore fully described, the

anode E'is' alsoaccurately aligned axially with respect to chambers 34,35 by the centering-pin referred to. The supports 12a. and aa for the grid and cathode are of a length to dispose the grid! andcathode 6 in concentric relation with respect to each otherandwith respect to 3.110(1855 when the supports referred :to are extended'int the end chambers 34, 36.

' In a modification to be described and as shown in Figure 5' the centr-alap'erture-in disc 15 is prointerior wall of tubular end section-l and fixed:

in position thereon by brazing 14 The open end of cathodesupportt is sealed by a'vitreous closuremember H.

'Tne grid "su port 12 has a channelled in'ter ior afiording communication between the interior of the envelope and exhaust tube 13, shown pinched off after exhaust. A portion of support l-2 forms a snugifit with theinteriorwall of the tubular end section 4 and is fixed in positionthere'on by being brazen thereto at .151 Both the cathode support 8 and grid support l2 abut end surfaces of the tubular end portions l and '4fof the euvelope to fix their longitudinal spacings;

The anode support comprises. a disc .l Shaving trodes results in an electrode arrangement wherein the electrodes are spaced from each other a-central aperture in whichanode '5' is mounted.

This disc is sealed across the tubular glass, seclarger side wall sections I, 2, 3 and 4 of the en sides infirstassemblingiajnd sealing togetherithei vided with Walls that define a chamber that is aligned with respect-'tothe end chambers :tforme'd ine'ndmembers I and 45in this .modification therefore three axially aligned chambers ar-e Iprovided for receiving electrode supports for disposing "the-electrodes in coaxial and concentric relation."

It will be noted that my mom providesfor an electrode arrangement wherein the electrodes are of different diameter to permit a first electrode to telescope into a second electrodepand to permit the first and second electrodes to telescope into a third electrode. All' the electrodes are thereforecoextensive axially of the device and in registering relationaround a common axis. The requirement for a common axis for the electrodes and co'extensive'fdisposition of the elecradially of said axis; and in {all directions jnonnai to said axis.

Therefore, the feature of my inventionjwhich requires thatthe side walls ofthe envelope 'ofjthe device be first assembled and sealed, is fadvantageous from the several standpoints' of preserving the seals of the device, avoidmg the danger of oxidation of the electrodes, and properly alignrings I4, I and 22..

- cylindrical glass members 2 and 3.

5 in'ga and spacing the-electrodes within the en- Vefop.;:. v z' Figure: 2 shows an exploded view of the relationship'of the previously prepared parts. which whenassembled and sealed together form .the structure ofmynovel electrondischarge device. -In this modification. of ,my invention the previously preparedparts, with the exception of the cathodeheater, are cylindrical inform and,in=- clude cathode 6, mounted on thesupport 8 and energized by cathode heater 2I having 1eads19 sealed through insulating closure .member II, .whichseals the open end of cathode support-:8. The envelope sidewall portionsinclude; metallic end portions I and 4 and cylindrical glassmembe'rs 2 and .3; The anode structure, includesdisc li-supporting anode. 5. The grid structure includes grid support I2 and grid 1. Exhaust tube -I3 :is in position to .be sealed over the opening in gridsupport I2 for communicating withthe interior of the envelope. I. They 'metallic'parts -8,.ZI,.4,'.1I2 and I3 aresealed together by brazing The dimensions'and shapes of each. of these previously prepared parts are predetermined in relation to dimensions and shapes of predetermined portions of'a centering pin 23 shown in Figure 3. This figure shows the parts forforming the envelope assembled. on centering pin 23 prior to scaling. member I forms a snug fit with the offset portion 23a of pin 23 and rests on a shoulder 24-thereoi. The cylindrical anode 5 forms a tight fit around another portion 23b of pin 2-3. and is limited in downward movement by shoulder 25 on this pin. Envelope member 24 forms a snug fit around a still further offset portion 230 of pin.23 and is limited in downward. movement by shoulder 26 on the pin. Since the offset'portions referred to of pin 23 are accurately centered, a snug enagement therewith of' envelop members and 4 and anode 5 results. in an alignmentof these members and anode 5. Since anode 5 is mounted in the center of disc I.6,.the alignmentof anode l 5 with members I and '4, also results in the alignvided with a flange having annular ribs-'or'guides 21 and 28' for engagement with end portions of I Such engagementof cylindrical glass members 2 and 3 with the annular ribs orguides 2'I-28 results in analignment of these glass cylinders .with

' envelope end portions I and 4. The alignment of these cylindrical glass members 2 and 3 with envelope portions I and 4 completes the align- -ment of all the parts entering into the structure of the device envelope.

. Thenext step involves the sealing together of the envelope parts referred to while maintaining their aligned relationship. The desired longitudinal spacing of the parts referred to is accomplished during the seal operation to be described. The sealing operation involves the application of heat to form glass-to-metal seals between cylindrical glass member 2, the envelope end member I and the disc I6. When the seal is eflected betweenthese members, anode 5 rests on shoulder 25 of pin 23. Each of the offset portions 23a, 23b and 230 is characterized by a predetermined length. Therefore when anode5 "rests on shoulder 25 of pin 23 there is a predeterm'in'ed longitudinal spacing between the lower.

The cylindrical interior space of edge of. anode 5 and the lower end of "envelope end portion; L1 .The next step istthe sealing of theglass member 3 to disc I6 and the envelope end 'portionxi4'. When these seals are 3.000111? plished the envelope end portion 4 rests on shoul der' 26 of pin 23., The longitudinal-spacing betweentheupper edge of anode-5 andtheupper end of envelope endportion. 4 is, therefore, of a .predeterined magnitude. The steps thus far described have an. accurate alignment of the parts forming the envelope of my, device and a proper longitudinal spacing. therebetween. The next step involves the. mounting of electrodes and electrodesupports within the envelope wherein the aligned and appropriately spaced parts-referred to auto 'matically align and properly space the electrodes -or.'passageways defined by envelope end mem hers I and 4. The'cathode and grid electrodes are. each suitably centered on their supports so that when these supports engage the interior walls of the envelope end members I andfi these electrodes are, accurately aligned. The cathode andgrid supports are also provided with portions thereof which limit their longitudinal movement within said end portions I and 4. This limitation of longitudinal movement of the cathode and grid supports results in an accurate longitudinalspacing of the cathode and grid with respect to each other as well as with respect to the-anode 5. g

. Figure 4' shows a jig which I may employ for centering the grid I on its support I2. Thisjig includes an outer member 29 for holding the grid" support I2 and an inner member 30 fitting snuglyinto the outer member 29 for holding the grid 1 in appropriately aligned and spaced relationship with respect to support I2.. Members 29 and 30 may be made of metals having difierent coefiicients of expansion, so that the inner memberexpands more than the outer member when similarly heated to accomplish atight fit between these: members to more accurately alignthem. Members 29 and 30 are given longitudinal movement relative to each other until the upper end of grid 1 abuts the lower end of grid support I! as viewed in Figure 4. Sufficient clearance around grid 1 is provided for brazing ring 32; which is heatedthrough aperture 3| in member 29 to fix grid I to its support. Jig members 29 and 30 are so constructed that they hold the grid I and the grid support I2 in accurate alignment and longitudinal spacing during the brazing step. A jig employing similar principles may be used to center cathode 6 on its support 8.

' After the cathode and grid electrodes are thus accurately mounted on their supports. they. are inserted into the envelope. Grid I and grid support I2 are inserted in the envelope and section 4 with shoulder 33 of grid support I2 abutting against the upper end of end portion 4 and sealed thereto by brazing ring [5. During. this brazing step, a cooling clamp may be employed to absorb the heat required for the brazing. The portion I2-a of the grid support fitssnugly within the cylindrical space 34 of envelope endporresulted in I tion 4'; This results in anaccurate alignment and spacingof grid -1 with respect to anode 5." V

' 'Cath'ode 6 and ,catho'desupport 8-are next 'insertedin envelope end portion I with the shoulder35 of the cathodesupport abutting against the lower end for this portion. The portion 8a of the cathode support fits snugly within' thecylindricalspace -36 in-"th'e' envelope end portion I. This results in an accurate alignment and spacing of cathode'fiwith respect to grid "land anode 5. As has been stated before herein, the longitudinal dimensions of the cathode and grid and their supports are predetermined, whereby the cathode and'grid each-may have a-length equal to that of the anode. The'cathode and grid supports'are each provid'ed-witha length from their shoulders 33 and'35 totheir-ielectrode supporting ends which accurately positions the cathode and gridwithin the cylindrical space defined by anode 5. The electrodes, therefore, are accurately aligned'and may -be characterized by a displacemerit that extends o'nly-in a radial or'late'ral' sense.

'- Cathode heater 2l"is 'nex'tiinserted into the cathode 6 and the open end of-the cathode sup -port is sealed by sealing member I I. l

- The grid 1 and grid support 'l'zareprovided with a channel communicating with theinterior of the device envelope. Exhaust tube I3is next brazed to the upper end'of this channel as .viewed iii-Figures 1 and 2 by brazing ring 22 and the envelope is evacuated. The exhaust tube is .then closed as by pinching and the device is complete. r I 1 I It will be seen, therefore, that according to the novel method of my invention electrodes are mounted in critically 'aligned'and spaced relationshipswithin an envelope, the resultant structure being characterized by many advantages. Moreover this method inherently provides;a=procedure which permitsthe desired type of "leads for ultra high frequency use to be employed while assuring good seals, freedom .from oxidation of the electrodesby theiheat required for such'seals,

of glass cylindrical members 2 and 3.; It does,

however, require a modification of the structure of cathode support Aland anode support 38. The

, exhaust tube is shown brazed tothe end of anode support 38,:thev support and, anode having interior channels communicating with the "interior or the envelope. v m I f m Figure '6 shows'a further'modificationwherein a centering pin 4| has tapered portions and '43iwhich engage correspondingly tapered interior wall portions of envelope end members 44 and. Phil! is provided with a cylindrical portion 46 'which" receives anode 5 inia 'snugfit; Int-his modification anode 5 ,7 and envelope end portion M'areac'curately centered by engaging cylindri- In this-modification the anode, 5 occupies the largercylindricalspace-dli in end 'memberd whilethecathode support occupies the smaller cylindrical spacein end'memher 4. This modification requires-no change-in "the structure of;envelope end members land 4, or

cal portion and tapered portionfl, respec; tively, of the pin. Envelope end portion 45 --becomes centered only during the sealing. operation when this member is brought into snug engage:

ing stepsifor the. completion of" the device are similar to those referred to in connection with previously described j'modification ofiEigures i1 and 2. v. .2 While the invention has been described by treferen'ce to severalembodiments' thereof it is to be clearly understood it is not limited thereto: While these embodiments involve-the use. of cylindrical and tapered parts, it is obvious that parts of other configuration may be used without departing from theinvention; and although the useof the invention in 'adtriode has been described itzcan with equal advantage-be employed in a diode or in a' device having more than three electrodes. It is, therefore, desired toinclude these and other modifications which maysuggest themselves to persons'skilled in the art within the scope of the appended claims.

"I claim: v i 5, I 1. An ultra high-frequency electron" discharge devicehaving an envelopeand electrodes mounted therein,i end portionsof said envelope defining end chambers therein"of'predetermined dimensions; said portions being in alignment with" each other, and supports for said electrodes extending into said chambers, said supports having predetermined dimensions for snug engagement with vthe side wallsyof said :endchambers and for supporting said electrodes in predetermined spaced relation within said envelope, and includingportions having larger transverseareas thanvsaid electrodes, 'and'ot-her portions transversely coextensive witlirespect'to said electrodes.

2. An ultra high frequency electron discharge device having an envelope andat least two electrodes mounted therein, wall portions of said envelope atcpposite'rendsther-eof defining chamberstherein of predetermined dimensions said Wall portions being inalignment in predetermined spaced relation, supports for said electrodes extending; 1 into ;said chambers and hav- 'ing predeterminedJdimensions'for snug engagement with the Walls {Of said chambers and for supportingsaid electrodes in predetermined registering spaced relation, said electrodes being-automatically aligned and accurately p'ositionedin said envelope whenssaid supports are received determined dimensions, supports for two other of :said. electrodes extending. into said end portions, said supports having predetermined dimensions for forming a snug fit with said walls, and for supporting said two other of said electrodes in telescoped and concentric relation with respect to each other and with respect to said one oi! said electrodes.

4. An ultra high frequency electron discharg device having an envelope and two electrodes mounted therein, said envelope having a metallic end portion and a glass portion, said end portion having walls defining a chamber of predetermined dimensions, a metallic disc sealed to said glass portion, a hollow electrode supported on said disc within said envelope, and a support for the other of said electrodes extending into said chamber and having dimensions for forming a snug fit with said walls of said chamber, and for supporting said other of said electrodes in alignment with said first-mentioned electrode and in predetermined radially displaced relation thereto.

5. An ultra high frequency electron discharge device having an envelope and electrodes mounted therein, said envelope defining two aligned spaces at opposite ends thereof, two supports for two of said electrodes extending into said spaces and having a predetermined cross sectional configuration for forming a snug fit. in said spaces, a support for a third of said electrodesv disposed intermediate the ends of said envelope, said last named support defining a space aligned with said two aligned spaces for receiving said third of said electrodes, said two supports extending axially of said envelope to the third or said electrodes, said electrodes having cylindrical forms of different diameter and being substantially equal in length, whereby said electrodes are disposed in telescoped relation around a common axis.

6. An ultra high frequency electron discharge device having an envelope and electrodes mounted therein, said envelope defining one passageway therein, supports within said envelope for said electrodes, one of said supports extending into and forming a snug fit in said passageway, one of said electrodes being centered on said one of said supports, another of said supports defining a passageway therein aligned with said first-mentioned passageway, an electrode cen-- tered in said another of said supports, one of said electrodes being hollow, and the other of said electrodes entering said one of said electrodes, whereby said electrodes are disposed concentrically in telescoped relation. 1 1

7. An ultra high frequency electron discharge.

device having an envelope and electrodes mounted therein, supports within said envelope for said electrodes, end portions of said envelope and one of said supports defining aligned passageways, electrodes of equal length centered on said supports and having hollow interiors, one of said elecenvelope for receiving said supports in alignment with each other, said means comprising aligned interior portions of said envelope, and means for determining the longitudinal displacement of said supports forcausing said electrodes to observe a registered relationship, said last named means comprising stops on said supports.

9. Anultra high frequency electron discharge device having an envelope including longitudinally joined end and intermediate sections, said sections having passageways extending longitudinally of the envelope and in alignment with each other, a disc-shaped lead-in conductor sealed across the intermediate section of said envelope and supporting an electrode at its central portion, at least two other electrodes within said envelope, supports in said end section on which said two other electrodes are centered, said supports hav ing dimensions permitting the entry thereof in snug fits in the passageways in said end sections, and stop means on said supports for determining the longitudinal displacement of the support and the longitudinal relationship of said electrodes.

10. An ultra high frequency electron discharge devicehaving an envelope and electrodes mounted therein, said. envelope having longitudinally aligned interior portions, supports in said envelope for said electrodes, said electrodes and said supports being longitudinally aligned, said supports being received in snug engagement by said interior portions to align said supports with each other, and means for fixing the longitudinal displacement of said supports from each other, whereby said electrodes are aligned in registering relationship, at least two of said supports serving as lead-in conductors for two of said electrodes.

11. An ultra high frequency, electron discharge device having an envelope and electrodes mounted therein, said envelope having-longitudinally aligned interior portions, said portions defining passageways therethrough, supports within said envelope for said electrodes engaging said passageways for supporting said electrodes in mutually aligned and registering relationship, said aligned relation being determined by snug fit engagements between said passageways and said supports, stop means on said supports,'said registering relation being determined by said stop means.

DON'NELL W. POWER.

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

UNITED STATES PATENTS Number Name Date 2,353,743 McArthur 1 July 18, 1944 2,402,119 Beggs June 18, 1946 2,391,927 Segerstrom Jan. 1, 1946 2,405,915 Vansant Aug. 13, 1946 2,411,184 Beggs Nov. 19, 1946 2,411,522 Chevigny Nov. 26, 1946 2,422,324 Watrous June 17, 1947 2,444,281 Chamberlin June 29, 1948 2,446,017 McArthur et a1. July 27, 1948 2,446,269 Drieschman Aug. 3, 1948 2,446,270 Eitel et al Aug. 3, 1948 2,458,693 Drieschman et al. Jan. 11, 1949

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