US2383925A - Electron discharge device - Google Patents

Description

Aug. 28, 1945. J. w; wEsT 2,383,925

ELECTRON DISCHARGE DEVICE vFiled Nov. 1, 1944.

F/aa /7 6 /NVENTOR J. W WEST er.

ATURNEY Patented Aug. '28, 1945 U N [TED STATES PATEN lF11' I C E t i2,383,925 y ELVECTRON *DISCHARGE DEVICE Jenn w. west, .reeksen Heights, N. Y., signoria i Bell Telephone Laboratories, IncorporatecLNew York, N. Y., a corporation of New York Application November 1, 1944, Serial No. 561,393

(ci. 25o-27.5)

8 Claims.

This invention relates to electron discharge devices and Vmore particularly to the 'terminal base 'for such devices.

In the mounting 'of electron vdischarge `dn-:vices especially vdesigned for use in ultra-high sfrequency radiation and reception usually has been .the practice to eliminate the metallic shell cemented 'to the `stem of the device which supports the terminal base to `overcome capacitance effects introduced intothe operating vcircuit `by the shell. (.'tertain present 'forms of `such devices have a molded glassl stem vwith the electrode conductors sealed in individual bosses 'on the lstern vand in `order to protect the fragile conductors Vand facilitate the insertion and removal of the device from associated apparatus it has been 'the custom to apply 'a ceramic disc 'having rigid terminals to the boss end of the device.

This construction has proved satisfactory provided the device 'is not subjected to excessive shocks and concussions, such as are experienced on 'board ship during storms or under battle conditions. Such forces strike the large mass ofthe bulb of the device above the base and may either fracture the fragile conductors or cause cracking of the seals in the boss portions of the stem thereby rendering the device useless. Similar effects result lunder excessive vibration occurring in other mobile craft, such as land and sea vehicles and airplanes.

An object of this invention is to protect the seals and conductors of such devices against destructive effects of vibrationandshock.

Another object of the invention .is to provide a. cushion coupling between the device and the base which does not introduce ycapacitance effects in the operating circuit. l n y A further object ofthe invention is to facilitate the assembly of the device to the base whereby strains on the seals are prevented.

A still further object of the inventionfis toprevent distortion of the fragile conductors during insertion and removal of the device `from asocket mounting thereby Aavoiding damage to the seals of the conductors.

These objects .are `attained in .accordance with the various aspects of this .invention ,by incorporating one .or more sockets v4or cups onor in the base toreceive the .boss seals of .they device .and providing `a .cushion material .inthe cup toprotout the :seals :and conductors coupled to the terminaison the base.

In one specific embodiment of the: invention individual metallic cups 4,are securedto the .base miimgwiththe the hossesiextcnding fromthe stem o'f the device are embedded in the cup by cushion'material, suchas plastic 'ce'- ment, the 'conductors projecting from 'the boss 'seals being extended Ainto the terminals on the base'and'anchoredin the ends thereof. l

VThe advantages of this construction are' more solid coupling of the device tothe base and the protection of the fragile conductors fromirupture strain caused "by concussion forces directed at the large'mass :of the device yabove the base.

A feature of the cushion' coupling of the bosses and lconductors in the base is the distribution of the effects 'of lthe forcey over a larger area of the stem away from -the immediate vicinity of the seals sot'hat'theforce is dissipated without harm'- ful results. Furthermore, `the conductors areentirely enclosed and protected -by the cement .encasement so that .strains are eliminated at, the `point 'of the sealin'the glass boss of the device.

'The invention also contemplates various modiiications ofthe 'above construction such -as integral recessed projections on the base or hollow cavitiesformed in a flush type base wherein the boss seals of Ithe conductors are embedded .bythe cushion cement for protecting the coupling of the device to the ibase.

These and other features o'f the invention will become apparent from the .following `detailed description and the accompanying drawing.

Fig. l1 is a v'iew in relevation of a three-electrode device .embodying ,the base `of .this invention shown in cross-section;

Fig. 2 is a top -plan view ofthe base of this invention showing `.the 'line I-i from which `the sectional view of the base of lis taken;

Fig. 3 shows a similar device and base with a single cup for fthe .mounting assembly;

Fig. 4 illustrates .in .cross-section `another form of 'the base vin which fthe bosses of the device, shown ,partially in dotted line, are seated in integral sockets 4extending from the top of the disc base; .n 5 .shows-a top lplan view-of the base illustrated .in Fig. 4 with lthe line 4 4 indicating thedrectionofcross-sectioniof the .baseiof Fig. 4,; and

Fig. v6 is ,another form of fthe'base =0f this invention, partly broken away, to illustrate fthe` 4of -the device in the base. i

' Referring yto Fig. i, an embodiment of `une invention is .illustrated in connection with a `threeelectrode -or amplifier type electrondischarge device especially adapted :for ultrahigh frequency operation which comprises `an :enclosing vessel I0 :sealed tofa .molded glass stem H which is )proheating conditions in the seals of the conductors. v

The electrodes supported by the conductors in the stem are a thoriated tungsten lament or cathode, not shown, and a Vhelical grid I4 with i the lament supported by three vconductors in the stem, namely, two conductors being attached to the terminations of the filament and the other.

being connected to the center point of the filament to facilitate various operating require-- ments. The helical grid I4 is supported and attached to the remaining conductor in the stem. A cylindrical anode I5 is coaxially mounted about the cathode and grid within the vessel and is connected to a bent wire I6 sealed in the top of the vessel I0, the conductor I6 being connected to a terminal cap Il extending from the top of the vessel. The stem of the device is also provided with a central tubulation I3 which is sealed off after the device is completely evacuated. The discharge device is provided with a ceramic disc base I9 having a central aperture 20 for the depending tubulation I8 and a plurality of terminal pins or prongs 2l corresponding to the number of conductors sealed through the stem II, the conductors I3 extending through the hollow terminals and being soldered in the ends thereof.

The rigid tungsten conductors sealed in the Ibosses I2 and soldered in the ends of the terminals 2I being formed of highly refractory metal are brittle or fragile and may be fractured'when subjected to intensive percussive strain occasioned by concussion forces striking the large mass of the enclosing vessel I0' and concentrating the effect of the forces at the weakest points of the conductors where they'arev sealed in the glass bosses I2. Even if oneor more conductors are not fractured the strains produced by the forces are apt to cause cracking of the seals in the glass bosses thereby causing leakage of air into the highly evacuated container with a resulting loss of efticiency in the operation of the device and the complete deterioration of the internal electrodes which can only be remedied by replacing the device.

In accordance with this invention these difficulties are overcome by surrounding the individual glass bosses I2 with metallic cups orsockets 22 which are secured to the top of the base I9 in alignment with the terminals 2I. These cups enclose the protruding glass boss seals I2 and the conductors I3 extending into the terminals 2I and the individual boss seals are rigidly fixed in the cups by a basing cement 23, for example of marble flour, rosin and shellac, which solidifies in the cups and completely embeds the boss seals and conductors within the cups so that the cups and cement form a cushion absorption coupling between the stem and the base to dissipate the percussive force directed toward the device and prevent or cut ol further transmission of the force to endanger the junction of the'glass seals or damage the fragile conductors protectedy Fig. 3 shows a modification of the base as ap plied to a form of device such as a half wave rectier having an internal electrode assembly similar to Fig. 1 except that the grid is omitted. In this form of construction the mounting of the device on the base I9, in which the three conductors of the cathode extending into the terminals 2I would provide an unbalanced support of the device, is strengthened by a dummy lead-in wire 24, which is sealed in the remaining glass boss I2 to equalize the supporting connections of the device on the base. In this construction it may be desirable to anchor the device tothe base by a single metallic cup 22 which surrounds the boss seal having the dummy leadinV Wire 24 so that the cement filling 23 within the cup firmly anchors the device to the base. It will be noted in this construction that the mounting of the device on the base I9 exposes the remaining conductors I3 extending into the terminals 2I. However, the localized anchoring provided by the single Cup 22 and the cement around the dummy seal of the device provides suicient rigid coupling of the'device and base so that excessive strains do not endanger the exposed conductors connected .to the other terminals in the base. The four seals are spaced away from the end surfaces of the terminals 2l in the base to prevent frictional contact between the glass and metal which would be apt to cause cracking of the glass at the sealing point if the device were subjected to sudden jars impacting the device in a downward axial direction.

While the construction shown vin Fig. 3 utilizes a single cushion coupling member surrounding a dummy lead-in wire, it is, of'course, understood that a similar constructionmay be applied to the amplier type of device, 'shown in Fig. 1, in which the single coupling member would surround an active conductor extending through the stem. Furthermore, while 'the invention has been described with respect to fragile conductors, such as tungsten, sealed in high melting point glass with the depending boss seals, it should be understood that the invention is not limited to such a construction since the protective coupling cups may embrace the boss seals oi dierent types of devices in which the conductors for the internal elctrodes are formed of other materials than tungsten, for example, alloys or composite conductors which are readily sealed in various compositions oi glass.-y

A modification of the inventionl lis shown in Fig. 4 m which the individualY boss'seals are embedded in cups or sockets formed integral with the base and separate cup components are eliminated. In this form the base is provided with a disc portion 25 and a plurality of upwardly extending cup portions or sockets 26 which are formed integral with the disc portion either by molding or machining an linsulating mass having high dielectric properties such as possessed, for example, by `phenolic resins, ceramics and silicate compositions. After the base is molded or machined the only operation necessary is to aix the terminal pins 2l to the disc portion in alignment with the sockets formedon the opposite side of the disc and the boss seals of the device will be completely protected in the cup portions 2B of the base by the cement filling therein to attain the same advantages as described heretofore in connection .with Fig. 1. ,i

Similar results can be achieved with the modiiication of the base, as shown in Fig. 6, in which a thick block of moldable or machinable insulat.

ing material 21 is provided with a plurality of cylindrical recesses 28 to receive the boss seals of the device and anchor them therein by the cement filling so that the top of the base is substantially` flush with the bottom wall of the stem Il.

While the invention has been described in various aspects and specific constructions of types of bases utilized in protecting the delicate seals and conductors of discharge devices against damage due to shock or excessive strainit will be apparent that various modications may be made in the detailed construction of the base of this invention without departing from the scope of the invention as denned in the appended claims.

What is claimed is:

1. A base for a discharge device having a plurality of boss seals projecting from one end and conductors extending through the boss seals, comprising an insulating disc member, a plurality of terminals secured to said member for coupling to said conductors, a cup portion on said disc member associated with one of said terminals and embracing the boss seal of the respective conductor attached-to the terminal, and a filling of cushion material in said cup portion embedding said boss seal and conductor therein.

2. A base for an electron discharge device having a plurality of boss seals projecting from one end and conductors extending through said boss seals, comprising an insulating disc member, a plurality of terminals secured to said member for coupling to said conductors, said boss seals and conductors being `positioned in alignment with said terminals, a metallic cup interposed between one of said terminals and the stem of the device and surrounding the respective boss seal and conductor, and a cement filling in said cup -afxing said boss seal therein.

3. A base for an electron discharge device having a plurality of boss seals projecting from one end and conductors extending through said boss seals, lcomprising an insulating disc member, a plurality of terminals secured to said member for coupling to said conductors, a plurality of metallic cups individually mounted on said disc member and coupled to the respective terminals, said cups enclosing said boss seals and conductors, and a cement filling in said cups securing said boss seals therein.

4. A disc type base for an electron discharge device having a plurality of conductors sealed through individual boss seals on one end thereof, comprising an insulating disc spaced from the boss end of said device and having a plurality of terminals to accommodate said conductors, and a cup portion on said disc base embracing one of said boss seals and being rigidly aiiixed thereto.

5. An electron discharge device comprising an enclosing vessel having a molded stem including a plurality of boss seals projecting therefrom, a

plurality of parallel conductors extending through said seals, electrodes in said vessel supported by said conductors, a ceramic disc base adjacent said boss seals, terminals carried by said base and accommodating said conductors, metallic cup members between said base and said stem and surrounding said boss seals, and a filling of cement material rigidly afxing said boss seals within said cup members. A

6. An electron discharge device comprising an enclosing vessel having a molded stem including a plurality of boss seals projecting therefrom, a plurality of parallel conductors extending through said seals, a cathode and anode supported in said vessel, said cathode being connected to a plurality of said conductors, one of the remaining conductors being a dummy and wholly insulated from the electrodes in said vessel, a disc base having terminal pins secured to said conductors, said base being located substantially ush with the ends of said boss seals, a metallic cup secured to said base and surrounding said dummy-conductor, and a cement filling embedding said dummy conductor and the respective boss seal therein.

7 A base for an electron discharge device having conductors extending through boss seals, comprising a disc member having integral cup portions extending from one of the surfaces thereof, a plurality of terminal pins extending from the opposite surface in line with said cup portions, said cup portions and terminal pins accommodating said boss seals and conductors respectively, and filler means axing said boss seals within said cup portions.

8. A base for an electron discharge device having conductors extending through boss seals, comprising a molded insulating disc having a plurality of depressions therein a plurality of terminal pins extending from said disc and coaxial with said depressions, said boss seals being located Within said depressions and substantially enclosed by said base, and a lling of cement in said depressions embedding said boss seals therein.

JOHN W. WEST.

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