US2111625A - Electron discharge device - Google Patents

Description

R. A. HEisuNG ,H l L25' ELECTRON DISCHARGE DEVICE Filed 0013. I5, 1955 OUTPUT A TTORNEY Patented Mar. 22, 1938 PATENT OFFICE ELECTRON DISCHARGE DEVICE Raymond A. Heising, Summit, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application October 3 8 Claims.

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

As is known inthe art, in electron discharge devices including at least a cathode, an anode and a control electrode or grid, the electrons emanating from the cathode are subjected to the potential on the control electrode or grid in their passage to the anode. In present devices the electrons are under the influence of the grid potentials throughout a relatively large distance in the path the electrons traverse in passing to the anode. At ultra-high frequencies, the timerequired for the electrons to traverse the distance in which they are acted upon by the grid potentials may become too great a part of the cycle at which it is desired to operate the device. To overcome this, it has been proposed to make the electrode spacings extremely small. However, the attainment of such small spacings involves mechanical and electrical diiculties and, furthermore, may necessitate the use of relatively small electrodes so that the power output obtainable from devices so constructed is relatively o small.

In electron discharge devices of conventional construction, at ultra-high frequencies the rapidly reversing grid potentials cause a large proportion of the electrons emanating from the cathode to -execute a to and fro or oscillating motion between the grid and the cathode, which motion results in a power loss. Also, 'as a result of this motion, the passage of some of the electrons from the grid to the anode is not iniitiated until late in the cycle so that these electrons extract energy from the grid circuit which y is not compensated for by movement of the electrons away from the grid and to the anode. The

resulting loss of energy, which is commonly` known as the active grid loss, becomes of appreciable magnitude at ultra-high frequencies,

One object of this invention is to amplify and to generate impulses of ultra-high frequencies. Another object of this invention is to reduce the active grid losses in electron discharge devices whereby the efficiency of such devices, particularly at ultra-high frequencies, is increased.

A further object of this invention is to enable the use of relatively wide electrode spacings and relatively large electrodes in electron discharge devices adapted for the generation and amplification of ultra-high frequency impulses.

In one illustrative embodiment of this invention, an 'electron discharge device comprises an 1935, Serial No. 43,298

(Cl. Z50-27.5)

incandescible cathode, a plurality of anodes having juxtaposed end portions, andv a plurality of control electrode elements disposed between the cathode and the anodes and adapted to influence electron beams from the cathode so that each of the beams impinges alternately upon two of the anodes.

In accordance with one feature of this invention an accelerating electrode is provided between the cathode and control electrode, the accelerating electrode having openings or slits in alignment with the juxtaposed end portions of two of the anodes and with the corresponding opening or space between two of the control electrode elements. This accelerating electrode preferably is operated at a positive potential greater than that of the anodes so that electrons passing in the region between the control electrode and anodes will be subjected to a retarding field and will have a low velocity when reaching the anodes, whereby a high operating efficiency is obtained.

In accordance with another feature oi this invention an auxiliary electrode is provided between the cathode and the accelerating electrode for focussing electron beams upon the openings or slits in the accelerating electrode. In one form, this auxiliary electrode may comprise elements on opposite sides of normals extending from the cathode to the openings or slits, and

these elements may have either a negative o1' positive potential relative to the cathode.

In accordance with a further feature of this invention another auxiliary electrode is provided for focussing the electron beams upon the anodes. This electrode may comprise a plurality of elements disposed between the control electrode elements and the anode and on opposite sides of lines extending from the openings or slits in the accelerating electrode to the juxtaposed end portions of the corresponding anodes.

The various electrodes may be arranged in parallel planes or may be arranged in coaxial cylindrical boundaries.

At ultra-high frequencies, a time delay may I occur between the potential changes on the control electrode elements and the corresponding deflections of the electron beams at their points o-f focus upon the anodes. In accordance with still another feature of this invention the deleterious effects of such time delay are prevented by a shifting in phase of the variable potentials appearing upon the control electrode elements and upon the anodes. For example, either the input or output circuit of the device may be de- Cil tuned slightly to provide the proper phase shift. If the device is utilized as an oscillation generator, the input and output circuits may be connected by a transmission line or other delay circuit to provide the proper phase shift in the potentials upon the control electrode elements and the anodes. This feature is claimed in my application Serial No. 79,485, iiled May 13, 1936, which is a division of the present application.

it will be apparent that in devices constructed in accordance with this invention the electrons iiowing to the anodes are subjected to the influence of the control electrode throughout but a small portion of the path they traverse in passing to the anodes. The small change of direction of motion of the electrons produced in the vicinity of the control electrodes is multiplied because of the movement of the beams analogous to levers so that a large displacement of the electron beams occurs at their points of focus upon the anodes. Hence, the electrodes may be relatively widely spaced and the difficulties attendant upon the extremely small electrode spaclngs used heretofore in ultra-high frequency de vices are obviated.

Furthermore, inasmuch as in devices constructed in accordance with this invention the electrons have a very high velocity as they come through the openings in the accelerating electrode, the electrons will be under the influence of the control grid for but a small portion of a cycle at the operating frequency. The movement of the electrons under the influence of the potentials upon the control grid will be small and a correspondingly small energy loss will obtain.

The invention and the several features thereof will be understood more clearly and fully from the following detailed description with reference to the accompanying drawing in which:

Fig. 1 is a diagrammatic view showing the form and arrangement of the electrodes in an electron discharge device illustrative of one embodiment ofthis invention;

Fig. 2 is a diagrammatic view illustrating another embodiment of this invention wherein the electrodes are arranged coaxially;

Fig. 3 shows a typical amplifier circuit including an electron discharge device constructed in accordance with this invention; and

Fig. 4 illustrates a typical oscillator circuit including an electron discharge device constructed in accordance with this invention and including also a time delay element for providing a phase sluit between the potentials upon the control electrode elements and the anodes.

Referring now to Figs. 3 and 4 of the drawing, the electron discharge devices shown therein comprise, generally, a cathode I Il, a plurality of anodes II, and a control electrode I2 disposed between the cathode and the anodes. Disposed between the cathode i0 and the control electrode I2 is a focussing electrode I3. Another focussing electrode I4 is positioned between the control electrode I2 and the anodes II. An auxiliary or accelerating electrode I5 is arranged between the focussing electrode I3 and the control electrode i2.

As shown in Fig. 1, the cathode Iii may comprise a plurality of filaments I6, which may be connected in series or in parallel, arranged in a plane. The anodes il may be fiat plates I1 disposed at a very small angle to the cathode plane, with adjacent end portions overlapping. The control electrode i2 may include a plurality of pairs of linear metallic wires or rods I8 and I8a positioned parallel to the cathode plane and on opposite sides of normals I9 extending from the cathode plane to the overlapping end portions of the plates Il. The wires or rods I8 are electrically connected together, as by a conductor 60, and the wires or rods I8a are similarly connected together, as by a conductor 50a.

If the anodes II are operated at a positive potential, electrons will iiow from the cathode I0 to the anodes II in substantially linear paths and some of the electrons will pass between the wires or rods I8 and I8a of the control electrode and be subject to potentials upon the control electrode. Thus, if the potentials upon the wires or rods I8 and I8a are varied, the electron beams passing therebetween will be defiected in accordance with such potential variations and may be caused to impinge alternately upon two of the anode plates I1 as indicated by the broken lines 20 in Fig. 1.

The accelerating electrode I5 may be composed of a plurality of fiat plates 2| disposed parallel to the cathode plane and spaced to form openings or slits 22 in alignment with the normals I 9. Alternatively, the accelerating electrode l5 may be a single fiat plate having suitable openings or slits therein. Preferably the electrode I5 is operated at a greater positive potential, relative to the cathode I0, than the potential on the anodes II so that the electrons are subjected to a retardlng force between' the control electrode I2 and. the anodes il and, therefore, will have a relatively low velocity when reaching the anodes, whereby a high operating eiclency is obtained.

The electrode I3 may include a plurality of pairs of metallic rods or Wires 23 electrically connected togethenas by a conductor 5I, and positioned parallel to the cathode plane and on opposite sides of the normals I9. The rods or wires 23 may be operated at either a positive or negative potential, the vpotential preferably being such that the electron beams are focussed upon the dagenings or slits 22 in the accelerating electrode The electrode I4 similarly may be composed of a plurality of pairs of metallic rods or wires 24 electrically connected together, as by a conductor 52, and arranged parallel to the cathode plane and on opposite sides of the normals I9. PreL- erably the electrode I4 is operated at a negative potential of such magnitude that the electron beams are vfocussed upon the overlapping end portions of the anode plates I'I.

As indicated by the dotted lines 25 in Fig. 1, electrons emanating from the cathode I0, under the inuence of the positive potentials upon the anode plates I'I and the plates 2| of the accelerating electrode I5 travel toward the accelerating electrode I5. The electrons are subjected to the field of the elements 23 of the electrode I3 and are focussed thereby upon the openings or slits 22 and, because of their high velocities, pass through the openings or slits and between the elements I8 and I8a, of the control electrode I2. If the elements I8 and Illa are at the same potential, the electrons tend to spread uniformly after passing the control electrode. This tendency to spread is counteracted by the field of the elements 24 of the electrode I4 and the electrons are concentrated to form beams each focussed upon the overlapping end portions of the anode plates Il. If an alternating potential is applied between the elements I8 and I8a each of the electron beams will be deiiected in accordance with the potential variations and impinge alternately upon two of the anode plates I1, as indicated by the dotted lines 20, the plates I1 being so connected that the electrons flowing thereto from the several beams are in phase. For example, if a device includes four anode plates I1, as shown in Fig. 1, alternate plates I1 may be electrically connected together, as by conductors 53.

As shown in Fig. 2, the invention may be embodied also in electron discharge devices having coaxially arranged electrodes. In this embodiment, the cathode I may be a single linear iilament or a plurality of laments arranged in a cylindrical boundary, and the focussing electrode I3 may comprise a plurality of metallic linear Wires or rods 23 which are equally spaced, parallel to each other and to the cathode I0, and are arranged in a cylindrical boundary about and coaxial with the cathode. The accelerating electrode I5 may include a plurality of arcuate plates 26 arranged in a cylindrical boundary coaxial with the cathode I0. The control electrode elements I8 and I8a, which may be Wires or rods disposed parallel to each other and to the cathode I0, are disposed-in a cylindrical boundary coaxial with the cathode I0, the elements I8 lbeing electrically connected together, as by a conductor 50, and the elements I8a being similarly connected together, as by a conductor. 50a. Likewise, the elements 24 of the focussing electrode I4 may be linear Wires or rods disposed parallel to each other` and to the cathode I8 and arranged in a cylindrical boundary coaxial with the cathode I0. The anodes II may be arcuate plates 21 having overlapping end portions and VA typical amplier circuit incorporating an electron discharge device constructed in accordance with this invention is illustrated schematically in Fig. 3. As shown in this figure, the corresponding elements'l and I8a of the control electrode I 2 are connected to opposite ends of the secondary 2B of an input transformer T1, the midpoint of the secondary 28 being connected to the positive terminal of a source, suc'as a battery 29. The anodes II are connected to opposite ends of the primary 30 of an output transformer T2, the midpointrof the primary being connected to a suitable positive tap on the battery 29.

Another source, such as a battery 3| is provided for applying suitable negative potentials to the focussing electrodes I3 and I4. The accelerating electrode I5 may be connected to the positive terminal of the battery 29. Y

Appropriate condensers 32, 33 and 34 may be connected between the cathode I0 andthe focussing electrode I3, accelerating electrode I5 and anodes II as shown. i

In the typical oscillator circuit illustated in Fig. 4, the anodes II are connected to opposite ends of an inductance 35 which is shunted by a suitable variable condenser 36. Similarly, corresponding elements of `the control electrode I2 are connected to opposite ends of an inductance 31, which is in parallel with a variable condenser 38. The midpoint of the inductance 31 is connected to the negative terminal of the source 3| through a resistance 39 shunted by a condenser 40 At ultra-high frequencies, because of the electron transit times, a time delay may occur between the potential changes on the elements I8 and I8a of the control electrode I2 and the corresponding deections of the electron beams at their points of focus upon the anodes II. This time delay may be counteracted by slightly detuning either the control electrode or anode circuits by varying the condenser 38 or 36, respectively. The requisite shifting in the phase of the alternating potentials upon the control electrode I2 and anodes II to counteract the time delay may be obtained also by coupling the inductances 35 and 31 by a suitable time delay circuit such as a short transmission line 4I, suitable stopping condensers 42 being connected in series with the line 4I.

Although specific embodiments of this 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 a cathode, a plurality of anodes having juxtaposed end portions, control electrodes between said cathode and said anodes forming an opening in alignment with said cathode and said end portions, and means for focussing an electron beam fromsaid opening upon said anodes including electrode elements disposed between said control electrodes and said anodes.

2. An electron discharge device comprising a cathode, a pair of anodes having juxtaposed end portions, an eccelerating electrode between said cathode and said anodes having an opening in alignment with said cathode and said end portions, means for focussing an electron beam from said cathode upon said opening, and control electrodes on opposite sides of said opening.

3. An electron discharge device comprising a cathode, a pair of anodes'having juxtaposed end portions, an accelerating electrode between said cathode and said anodes and having an opening in alignment with said cathode and said end portions, means including an electrode between said cathode and said accelerating electrode for 'focussing an electron beam from said cathode upon said opening, means including an electrode between said accelerating electrode and said anodes for focussing said beam upon said anodes, and means including a control electrode between said accelerating electrode and said anodes for delecting said beam alternately to said anodes.

4. An electron discharge device comprising a cathode including a plurality of filaments arrangedin a plane, a plurality of pairs of anodes disposed substantially parallel to said plane, adj'acent anodes having overlapping end portions, control means including a plurality of pairs of members disposed in a plane parallel to said cathode plane, the members of each pair being disposed on opposite sides of lines extending from cathode plane to said overlapping end portions, and an electrode between said members and said anodes for focusing electron beams upon said overlapping end portions.

5. An electron discharge device comprising a cathode having a plurality of laments disposed in a plane, a plurality of pairs of anodes disposed substantially parallel to saidv plane, adjacent anodes having overlapping end portions, control means between said cathode and said anodes including a plurality of pairs of members disposed in a plane parallel to said cathode plane and on opposite sides of normals extending from said cathode to said overlapping end portions, an accelerating electrode between said cathode and said control electrode having openings in alignment with said normals, an electrode between said cathode and said accelerating electrode for focussing electron beams upon said openings, and another electrode between said control electrode and said anodes for focussing said beams upon said overlapping end portions.

6. An electron discharge device comprising a cathode. a plurality of pairs of anodes disposed about said cathode and having juxtaposed end portions, control means including a plurality of pairs of members arranged in a cylindrical boundary coaxial with said cathode, the members of each of said pairs being positioned on opposite sides of radii extending from said cathode to said juxtaposed end portions, means directly connecting alternate anodes in electrical parallel, and means directly electrically connecting said members in two groups such that the electron beams impinging upon each of said anodes are substantially in phase.

7. An electron discharge device in accordance with claim 6 comprising an electrode 'between said members and said anodes for focussing electron beams upon said 'juxtaposed end portions, said focussing electrode including a plurality of members disposed on opposite sides of said radii and in a cylindrical boundary coaxial with said cathode.

8. An electron discharge device comprising a cathode, a plurality of pairs of arcuate anodes having overlapping end portions, arranged in a substantially cylindrical boundary coaxial with said cathode, control means including a plurality of pairs of members between said cathode and said anodes, lying in a cylindrical boundary coaxial With said cathode and disposed on opposite sides of radii extending from said cathode to said overlapping end portions, a cylindrical accelerating electrode between said cathode and said control electrodes and coaxial therewith, said accelerating electrode having openings in alignment with said radii, and an electrode for focussing elcetron beams from said openings upon said overlapping end portions including a plurality of members on opposite sides of said radii and lying in a cylindrical boundary coaxial with said cathode.

RAYMOND A. HE'ISING.

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