US2063341A

US2063341A - Electron discharge device

Info

Publication number: US2063341A
Application number: US756591A
Authority: US
Inventors: Arthur L Samuel
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1934-12-08
Filing date: 1934-12-08
Publication date: 1936-12-08
Anticipated expiration: 1953-12-08
Also published as: FR796386A

Description

D 1936. A. SAMUEL 2,063,341

ELECTRON DISCHARGE DEVICE Filed Dec. 8, 1934 2 Sheets-Sheet l INVENTOR A. L. SAMUEL A T TORNEV 2 Sheets-Sheet 2 INVENTOR A. L. SAMUEL Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE Telephone Laboratories,

Incorporated, New

York, N. Y., a corporation of New York Application December 8, 1934, Serial No. 756,591

14 Claims.

This invention relates to electron discharge devices and more particularly to such devices capable of generating and amplifying ultra-high frequency impulses.

One object of the invention is to decrease the losses, particularly dielectric, conduction, and radiation losses, in electron discharge devices and thereby to obtain a high operating efficiency.

Another object of this invention is to expedite the control of the oscillating frequency of ultrahigh frequency electron discharge devices.

In one embodiment illustrative of this invention, an electron discharge device, which may be of the general construction disclosed and claimed in my Patent No. 2,044,369, granted June 16, 1936,

comprises an enclosing vessel having vitreous end portions and an intermediate metallic portion adapted to serve as the anode of the device. The intermediate portion includes a cylindrical wall sealed at opposite ends to the vitreous end portions of the enclosing'vessel, which is provided with inwardly extending portions having grooves in which cathode and control electrode or grid elements are disposed. Leading-in conductors for the cathode extend through one of the vitreous end portions and a leading-in conductor for the control electrode or grid extends through the other of the end portions.

In accordance with a feature of the invention, the anode-control electrode circuit is completely within the enclosing vessel whereby dielectric losses are substantially reduced and a high operating efliciency is obtained. To these and other ends, a metallic member is mounted on the leading-in conductor for the control electrode and in proximity to the cylindrical wall and inwardly extending portions of the anode. The juxtaposed surfaces of the inwardly extending portions and of the metallic member are curved in opposite directions to form a substantially toroidal cavity. The walls of the member and of the inwardly extending portions bounding the toroidal cavity constitute an approximate toroid, the inductance of which together with the interelectrode capacities forms a tuned circuit. the cavity, of course, may be made such that this circuit is resonant at the frequency at which the device is intended to operate.

The metallic member is provided also with a cylindrical flange coaxial with the cylindrical wall of the anode and disposed thereadjacent to form a blocking condenser in the anode-control electrode circuit. Preferably, the capacity of this condenser is made large in comparison with the interelectrode capacities so that it will not be a disposed. The dimensions of 1 this invention, partly broken away and partly in 10 2 section to show details of construction more clear- Fig. 2 is an elevational view in cross-section of the device shown in Fig. 1;

Fig. 3 is a view in cross-section along line 3-4 of Fig. 1;

Fig. 4 is a detail view in cross-section showing the configuration of the juxtaposed portions of the anode and the metallic member in the device shown in Fig. 1, forming a substantially toroidal 20 inductance;

Fig. 5 is an elevational view in cross-section of another illustrative embodiment of this invention; and

Fig. 6 is a view in cross-section along line 6l of Fig. 5.

Referring now to the drawings, the electron discharge device shown in Fig. 1 comprises an enclosing vessel including vitreous end portions l and II having inwardly extending stems l2 and I3 respectively, and an intermediate metallic portion I4 hermetically sealed to the end portions Ill and l I. The metallic portion M which serves as the anode of the device, includes cylindrical walls I and I6 and inwardly extending portions", the surfaces [8 and IQ of which are curved or dished. The inwardly extending portions [1 are provided with diametrically opposite'substantial- 1y cylindrical grooves or cavities (see Fig. 3) and also with other diametrically opposite substantially cylindrical grooves or cavities 2| in which cathode and control electrode elements are The cathode elements may be linear filaments 22, for example of thoriated tungsten, which are disposed coaxial with the cavities or grooves 2| and are secured at opposite ends to resilient V-

shaped wires

23 and 24 secured to metallic sup ports or

rods

25 and 26, respectively, extending from the stem l2.

Each of the filaments 22 is encircled by a hellcal control electrode or grid element 21, the two grid elements 21 being secured to opposite edges of a fin formed of two metallic plates 28 secured together and fixed in a slot in a metallic support or rod 29 extending from the stem l2.

The corresponding electrode elements preferably are positioned as closely together as is mechanically and electrically feasible so that the electron transit times are exceedingly small and the device may be utilized for the generation and amplification of ultra-high frequency impulses. The metallic plates 28 and metallic portion ll of the enclosing vessel provide relatively large heat radiating surfaces so that the device may be operated at relatively high powers without deleterious heating of the control grid elements and anode.

When a device of the type described hereinabove is operated at ultra-high frequencies, the inductance and capacitance of the leading-in conductors are of material import and may be 7 of such magnitude as to prevent the facile and accurate tuning of circuits in which the device is utilized. Furthermore, at such ultra-high frequencies, it has been found that if the .tuned circuit includes the electrode supports or leading-in conductors material dielectric losses occur at the points where these supports pass through the. vitreous portions of the enclosing vessel.

In accordance with a feature of this invention, the foregoing difliculties are circumvented by enclosing the tuned circuit within the vessel of the device. To this end, a metallic member-is provided within the enclosing vessel and designed and associated with the electrodes so that it forms with the interelec'trode capacitances a circuit resonant to a desired frequency.

In one embodiment of this invention shown in Fig. 1, the metallic member may comprise a hub 30 provided with an axial bore 3| for receiving the inner end 32 of the support or rod 23 and having a threaded portion for receiving a support or rod 33 extending from the stem I3 and serving as the leading-in conductor for the control electrode or grid. The surface 34 of the metallic member toward the surface l9 of the anode is curved or dished and forms with the surface l9 a substantially toroidal cavity 35. The surfaces l3 and. 34 may be so designed that they form an inductance of a desired magnitude. For example, they may be designed so that, as shown in Fig. 4, they follow a circleof radius a, the center of the circle being a distance 6 from the axis of the toroidal cavity35. The inductance, then, may be ascertained from the relation microhenries where L is the inductance and a and b are the radii, shown in Fig. 4, expressed in centimeters.

The interelectrode capacities may be ascertained in waysflknown to those skilled in the art. Hence,-the electrodesa'nd the surfaces l9 and 34 .may be so constructed and arranged that a cirvanode-control electrode circuit within the enclosing vessel of the device; Preferably the flange 36 and wall It are spaced so that the capacitance therebetween is large in comparison with the interelectrode capacitances so that it will not materially affect the tuning of the anode control electrode circuit.

or grid, and the metallic portion ll Alternately, it may be coupled to the internal tuned circuit through the metallic portion I3 and one of the cathode leading-in

conductors

25 and 26.

In another embodiment of this invention illustrated in Fig. 5, the metallic member may in- .clude a right cylindrical portion 33 uniformly spaced from the wall it and forming a blocking capacitance therewith, and an elongated cylindrical portion 40 coaxial with the-wall I8 and having a flat end ll in juxtaposition to the flat surface 42 of the anode IT. The inductance of a the toroid of rectangular section formed by the

portions

39 and 40, the wall l6 and the anode I! may be made such that together with the inter- "electrode capacitances it forms a tuned circuit resonant to the frequency at which the device is intended to operate. inductance may be ascertained from the relation:

L is the inductance in henries,

Z is the distance between the surface l2 of the I anode and the wall of the cylindrical portion v 39 toward the surface 42, in centimeters, dzis the inner diameter of the wall i6, and d; is the diameter of the elongated cylindrical portion 40.

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

What is claimed is:

1. An electron discharge device comprising a highly evacuated enclosing vessel, a plurality of electrodes, anda metallic member within said vessel, disposed remote from one of said electrodes and in juxtaposition to another of said electrodes, said metallic member being electrically connected to said one electrode and forming an inductance with integral portions of said another electrode.

2. An electron discharge'device comprising a highly evacuated enclosing vessel, a'plurality of electrodes, and a metallic member within said vessel, electrically connected to one of said electrodes, said metallic member and another of said electrodes having juxtaposed surfaces bounding a substantially toroidal cavity. I

3. An electron discharge device comprising a highly evacuated enclosing vessel housing a cathode, an output electrode, an input electrode, and a metallic member electrically connected to said input electrode and disposed remote therefrom, said output electrode and said metallic: member having juxtaposed coaxial annular surfaces forming an inductance which together with the capacitances between said input and output electrodes constitutes a tuned circuit.

4. An electron discharge device comprising a highly evacuatedenclosing vessel housing a cylindrical electrode, another electrode within said first electrode, and a metallic member electrically connected to said second electrode; said metallic member and'said first electrode having juxtaposed surfaces bounding a substantially toroidal cavity.

5. An electron discharge device comprising'a plurality of electrodes, one of said electrodes having an annular surface and a cylindrical surface, and a metallic member electrically connected to another of said electrodes, said member having an annular portion in juxtaposition to said annular surface and forming an inductance therewith and having another portion in juxtaposition to said cylindrical surface and forming a capacitance therewith.

"6. An electron discharge device comprising a highly evacuated enclosing vessel, a plurality of electrodes, and an annular metallic member electrically connected to one of said electrodes, said member and another of said electrodes having integral juxtaposed portions bounding a substantially toroidal cavity and having other integral juxtaposed portions forming a condenser.

7. An electron discharge device of the high vacuum type comprising an electrode having a cylindrical wall and a portion extending inwardly from said wall, another electrode adjacent said first electrode, and a metallic member electrically connected to said second electrode, said metallic member having a portion in juxtaposition with said inwardly extending portion and forming an inductance therewith and having a cylindrical portion in juxtaposition to said wall and forming a condenser therewith.

8. A high vacuum electron discharge device comprising a cylindrical anode, an incandescible cathode, an electrode within said anode, and a member electrically connected to said electrode, said member and said anode having juxtaposed coaxial portions forming an inductance which together with the interelectrode capacitance forms a circuit resonant to the frequency at which said device is intended to operate.

9. An electron discharge device comprising an anode, a control electrode, a cathode, anda metallic member electrically connected to said control electrode, said metallic member and said anode having juxtaposed coaxial annular portions forming an inductance which together with the interelectrode capacitances forms a circuit resonant to the frequency at which said device is intended to operate, and said metallic member and said anode having other juxtaposed portions forming a blocking condenser in said circuit.

- 10. An electron discharge device comprising an enclosing vessel including a metallic portion serving as an electrodeof the device, another electrode within said first electrode, and a, metallic member within said vessel and electrically connected to said second electrode, said first electrode and said metallic member having juxtaposed annular arcuate portions bounding a substantially toroidal cavity.

11. An electron discharge device comprising an enclosing vessel including a metallic portion serving as the anode of the device, a cathode and a control electrode adjacent said metallic portion, a leading-in conductor for said control electrode, and a metallic member mounted on said leading-in conductor, said metallic member having a portion in juxtaposition to a part of said metallic portion and forming an inductance therewith and having a flange portion in juxtaposition to another part of said metallic portion and forming a condenser therewith.

12. An electron discharge device comprising an enclosing vessel including a metallic portion serving as the anode of the device, said metallic portion having a cylindrical wall and a portion metallic member having a portion in juxtaposition to said inwardly extending portion and forming an inductance therewith, and having another portion in juxtaposition to said cylindrical wall and forming a condenser therewith.

13. An electron discharge device comprising an enclosing vessel including a metallic portion serving as the anode of the device, said metallic portion having a cylindrical wall and a substantially circular portion extending inwardly from said wall,v a cathode and a control electrode adjacent 'said circular portion, and a metallic member electrically connected to said control electrode, said circular portion and said metallic member having juxtaposed surfaces bounding a substantially toroidal cavity, and said metallic member having a cylindrical portion coaxial with and in juxtaposition to said cylindrical wall.

14. An electron discharge device comprising an enclosing vessel including vitreous end portions and an intermediate metallic portion having a cylindrical wall and a portion extending inwardly from said wall, said inwardly extending portion having a plurality of grooves therein, cathode and grid elements in said grooves, means supporting said grid elements from said vitreous portions and serving as a leading-in conductor therefor, and a metallic member mounted on said means, said metallic member and said inwardly extending portion having juxtaposed surfaces forming a substantially toroidal cavity, and said metallic member having a cylindrical portion in juxtaposition to said cylindrical wall and forming a condenser therewitln AR'I'HUR L. SAMUEL.