US2186127A

US2186127A - Electron discharge device

Info

Publication number: US2186127A
Application number: US155018A
Authority: US
Inventors: Arthur L Samuel
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1937-07-22
Filing date: 1937-07-22
Publication date: 1940-01-09
Anticipated expiration: 1957-01-09

Description

Jan. 9, 1940. A. L. SAMUEL ELECTRON DISCHARGE DEVICE Filed July 22, 1957 F/c. 2 l,

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ELECTRON DISCHARGEA DEVICE y Arthur L. Samuel, Summit, N. J., assignor to Bell Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application July 22,

10 Claims.

This invention relates to electron discharge devices and more particularly to such devices, for example of the general construction disclosed in my Patent 2,063,341 granted December 8, 1936J especially suitable for the generation and ampliiication of ultra-high frequency impulses.

In electron discharge devices adapted for the generation and translation'of ultra-high frequency currents, for example currents of frequencies corresponding to wave lengths of one meter or less, the various electrodes, such as the cathode, control grid and anode, usually are spaced very closely inv^` order that very short transit times may be obtained, and the control grid, therefore, is of small dimensions. Consequently, during the outgassing treatment of the electrodes and the operation of the device, the control grid may become heated to unduly high temperatures. As a result, undesirable secondary emission from the grid Amay occur or the grid may be destroyed.

One object of this invention, therefore, is to prevent deleterious heating of electrodes in electron discharge devices so that the devices will be capable of handling safely relatively highv power.

Another object of this invention is to expedite the fabrication and assembly of electron discharge devices.

In one illustrative embodiment of this invention, an electron discharge device comprises an enclosing vessel including a vitreous portion and a metallic portion constituting the anode of the device, a cathode, and a control electrode assem- 35 bly. The control electrode assembly may include a grid between the cathode and the anode and a metallic tuning member forming an inductance and a capacitance of predetermined magnitude with the anode.

In accordance with one feature of this invention, the control electrode structure is provided with a relatively large surface metallic portion exposed or thermally coupled to the atmosphere whereby the heat dissipation from the control electrode assembly is increased and the grid thereby maintained at a safe temperature during the Voutgassing treatment of the electrodes and the operation of the device.

In accordance with another feature of this invention, the cathode and the control electrode structure are fabricated as a unitary assembly which may be inserted as a unit into the enclosing vessel and mounted therein! The invention and the foregoing and other features thereof will be understood more clearly and.

1937, serial No. 155,018

fully from the following detailed description with reference to the accompanying drawing, in which:

Fig. 1 is an elevational view in perspective of an electron discharge device illustrative of one embodiment of this invention, portions of the device being broken away to show details of construction more clearly; y

Fig. 2 is an elevational View mainly in crosssection of an electron discharge device illustrative of another embodiment of this invention;

Fig. 3 is a fragmentary view in cross-section showing a modification of the embodiment of the invention illustrated in Fig. 2; and

Fig. 4 is a fragmentary view in cross-section of a modification of the structure illustrated in Fig. 3.

Referring now to the drawing, the electron discharge device shown in Fig. 1 comprises an evacuated enclosing vessel having a vitreous portion I and a cup-shaped metallic portion Il hermetically sealed to the vitreous portion Il) and provided with an external annular flange I2 by means of which the device may be supported. Mounted upon and secured to the metallic portion II is an anode element having an extended cylindrical portion I3 and a generally annular portion I4 provided with diametrically opposite, parallel U-shaped recesses I5. The annular portion I4 of the anode element abuts a shoulder I6 in the inner wall of the metallic portion II and may be affixedv to this portion as by solder Il contained initially in an annular groove in the outer wall of the annular portion I4.

A control electrode structure is cooperatively associated with the anode and includes a metallic cylinder or sleeve l'coaxial with the annular portion I4 and provided at its inner end with diametrically' opposite slots in which a metallic plate I9 is fitted. The metallic plate may be locked in vposition by a plurality of cross members or wires 2| extending therethrough and through the cylinder I8, and carries a pair of grids 22, each disposed inone of the channels or grooves I5 and preferably coaxial therewith. Each of the grids may be composedv of a plurality of parallel U- shaped wires having their ends alxed, as by welding, to opposite faces of the plate I9 and further held in position by backing wires 23 also aiiixed, as by welding, to the plate I9. The mel tallic cylinder I8 is provided at its outer end with a. flared portion 24 hermetically sealed to a vitreous dished member 25, and is encompassed by a cylindrical metallic member 26 coaxial with and adjacent the cylindrical portion I3 of the anode member. The cylindrical member 26 is provided with a. flaring end 21 sealed hermetically to the vitreous portion I8 and is joined to the cylinder I8 by a metallic disc 28, rigidly aiiixed to both the cylinders I8 and 26, as by welding.

As described in my Patent 2,063,341 aforementioned, the members I8, 26 and 21 may be so dimensioned and disposed that they constitute an inductance with the anode, the inductance being of such magnitude, for example, as to form with the interelectrode capacitances a circuit resonant to the frequency at which the device is intended to operate. The cylindrical members I8 and 26 may be spaced to dene a blocking condenser of desired magnitude. A-suitable potential may be impressed upon-the control grids through a leading-in conductor 28.

As will be seen, the disc 28 and the members 24 and 21 arel exposed to the atmosphere and provide relatively large area heat radiating surfaces. Consequently, heat generated in the control electrode structure during operation of the device, and which might be retained because of the mass of this structure and particularly of the

tuning member

26, 28, will be dissipated rapidly so that this structure will be maintained at a relatively low and safe temperature and secondary emission from the grids 22 will not occur. The rate of heat dissipation may be further increased, if desired, by circulating a cooling medium, such as a stream of air, over the outer surfacesof the disc 28 and the end portions 24 and 21 so that the power capacity of the device may be increased accordingly.

Disposed within each of the grids 22 is a cathode 38, which may be a linear thoriated tungsten filament coaxial with the corresponding grid.

'I'he cathodes are supported and maintained in proper position to the anode and the grids by a structure which includes a pair of insulating blocks or discs 3| and 32 fitted within the metallic cylinder I8. The blocks or discs'3l and 32 are mounted on and spaced by a pair ofmetallic rods 88 supported by rigid leading-in conductors 34 sealed in the vitreous member 25, the blocks or discs being locked to the rods 33 as by metallic stubs 35 embedded in the blocks or discs and affixed to the rods. Mounted upon the rods 33 at the inner ends thereof are metallic strips or bands 36 which extend through oversized apertures 81 in the cylindrical member I8 -and are aiiixed to the cathodes 38 at one end thereof.

The cathodes 88 are supported at the other end by a rigid cross-arm or rocker member 38 which is pivotally mounted upon a4 pin 38 extending through and between a pair of rigid supports or uprights 48.` The supports or uprights 48 extend slidably through metallic bushings or bearings 4I in the blocks or discs 3i and 32 and are ernbedded at the lower end thereof in an insulating carrier or platform 42 to which they may be locked by metallic stubs or `wires 43. The carrier or platform 42 is supported by a helical spring 44 which is fitted at one end about a reduced hub 45 on the carrieror platform and is seated at the other end upon an insulating block 48 having a reduced portion 41 tted within the spring 44. In the fabrication of the device, the spring 44 is placed under compression so that it exerts an upward -force upon the carrier or platform 42, the force being transmitted to the cathodes 88 through the rods or uprights 48 and rocker member 38 so that the cathodes are maintained under tension during operation of the device.

'cal portion 58.

As will be apparent, the control grid and cathode structures constitute a unitary assembly which may be inserted into the anode as a unit and likewise removed as a unit to allow repair or replacement thereof.

In the embodiment of this invention illustrated in Fig. 2, the cathodes 38 are supported upon the metallic cylinder I8 of the control grid'structure. As shown in this figure, the grids 22 are mounted upon individual fins or plates 48 suitably afiixed, as by welding, to the outer surface of the cylinder I8. The cylinder I8 is provided with an internal annular flange 49 having sealed thereto a metallic disc 58 upon which the insulating block 46 is seated, the disc 58 being provided with a central recess for receiving a reduced portion I of the block. 'I'he platform 42 carried by the spring 44 is slidably fitted in the cylinder I8 and mounts the rods or uprights 48 supporting the rocker member 38.

The'leading-in conductors 52 for the cathodes 38, provided with insulating sleeves 53, extend through metallic eyelets 54 projecting from the,

cylinder I8, and are sealed thereto hermetically by vitreous beads 55.

The flared portion 21 of the'tuning cylinder, the

discs

28 and 58 and the cylinder I8 constitute walls of the enclosing vessel and provide relatively large heat radiating surfaces so that the heat developed in the control electrode structure during operation of the device will be dissipated rapidly and the grids 22 thereby maintained at a relatively low temperature. If desired, a cooling medium, such as a stream of air, may be circulated through the chamber formed by the members 21., 28, 58 and I8.

In a modification of the structure shown in Fig. 2, the vitreous portion I8 of the enclosing vessel may have sealed thereto a metallic member which, as illustrated in Fig. 3, includes a base portion 56 having a flange 51 sealed to the vitreous portion I8, and an inwardly extending cylindrical portion 58. 'I'he cylinder I8 of the control grid structure is frictionally fitted about the cylindrical portion 58 and the disc 28 engages and rests upon the base 58. 'I'he inner end of the cylindrical portion 58 may be sealed by a vitreous member 58 fused to an inwardly extending annular ila'nge 68 integral with the cylindri- Embedded in and extending through the'vitreous member 58 are the cathode leading-in conductors 52 which extend through apertures 6I in the cylinder i8 and are secured to the lower ends of the cathodes 38.

As shown in Fig. 4, the cylindrical portion 58 may have, alternatively, an upstanding, knifeedged annular projection 62 to which the vitreous member 58 is hermetically sealed.

Although specific embodiments of the invention have been shown and described, it will be understood of course, that various modifications may be made therein without departing from the scope and spirit of this invention as dened in the appended claims.

What is claimed is:

1. An electron discharge device comprising an enclosing vessel, a cathode, an anode, a control electrode, a metallic member connected to said including a grid in cooperative relation with said cathode and said anode, a hollow member supporting said grid and a cylindrical member integral with said hollow member, having a portion in juxtaposition to said anode and forming a condenser therewith, and an enclosing vessel portions of which are constituted by said hollow member and another portion of saidcylindrical member.

3. An electron discharge device comprising an enclosing vessel having a dished portion and a cylindrical metallic wall at one end of said dished portion, a metallic disc within the' confines of said wall and joined thereto, a cylindrical metallic member extending into said disc and sealed thereto,l said member having an exposed heat radiating portion, andan electrode mounted on said cylindrical member. i

4. An electron discharge device comprising an enclosing vessel having a vitreous portion, a metallic cylinder within and sealed to said vitreous portion, an annular disc member intermediate the ends of said cylinder and sealed thereto, a hollow member extending through said disc member, and an electrode mounted on said hollow member, said hollow and disc members and portions of said cylindrical member constituting walls of said enclosing vessel.

5. An electron discharge device comprising an enclosing vessel including a cylindrical metallic member at one end thereof one surface of which constitutes an external wall of said vessel, and an electrode structure mounted on said metallic member comprising a metallic sleeve iltted to the other surface of said metallic member and an electrode carried by said sleeve.

6. An electron discharge device comprising an enclosing vessel having a metallic wall adjacent one end thereof, a metallic annulus carried by said metallic wall, a metallic cylinder mounted on said annulus and having an open end in communication with the aperture therein, a grid electrode supported by said cylinder, a disc within said cylinder and sealed thereto intermediate the ends thereof. a cathode in cooperative relation with said grid electrode, and means mounted on said disc supporting said cathode.

7. An electron discharge device comprising an enclosing vessel having a dished metallic portion and a vitreous portion, an anode element mounted on said metallic portion and having a cylindrical portion, a metallic cylinder within said cylindrical portion and sealed to said vitreous portion, said cylinder having a part constituting a wall of said enclosing vessel, a metallic disc within and sealed to said cylinder, a metallic sleeve ailixed to said disc, a grid carried by said sleeve, a cathode, and means supporting said cathode supported by said sleeve.

8. An electron discharge device in accordance with claim 7 wherein said sleeve has a heat radiating portion extending outwardly from said disc.

9. An electron discharge device comprising an enclosing vessel including a cup-shaped metallic portion and a vitreous portion, aninwardly extending metallic cylinder sealed to said vitreous portion, an anode element having a cylindrical portion encompassing said cylinder and having also an annular portion, a hollow member supportedby said cylinder, a pair of grids moimted on said hollow member, a pair of cathodes each in cooperative relation to one of said grids, leading-in conductors extending through said hollow member and connected to said cathodes at one end thereof, and supporting means mounted on `said hollow member and engaging said cathod at the other end thereof.

10. An electron discharge device in accordance with claim 9 wherein said supporting meam comprises a platform slidably molmted within said hollow member, a rocker member carried by said platform and having its ends aihxed to said other end of said cathodes, and a helical spring sup-` ported by said hollow member and supporting said 40 platform.

ARTHUR L. SAMUEL.