US2000990A

US2000990A - Electron discharge device

Info

Publication number: US2000990A
Application number: US695407A
Authority: US
Inventors: Arthur L Samuel
Original assignee: Bell Telephone Laboratories Inc
Current assignee: AT&T Corp
Priority date: 1933-10-27
Filing date: 1933-10-27
Publication date: 1935-05-14
Anticipated expiration: 1952-05-14

Description

May 14, 1935. A. L. SAMUEL ELECTRON DISCHARGE DEVICE Filed Oct. 27, 1933 lNVENTOR ALSAMUEL 04am 6. flTTOR/VEY Me ia i935 I I V l I I: 2,000,990-

- N TE STATES PATENT orrlce ELECTRON DISCHARGE DEVICE Arthur L. Samuel, Orange, N. J., assignonto Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of York Application October .27, 193:, Serial No. 095.401 16 Claims. (01. 250-275) This invention relates to electron discharge de- 2, showing clearly the position oi. the insulating vices and more particularly to such devices coating on the wires constituting the output adapted for the generation of ultra-high freelectrode. quency oscillations. Referring to the drawing, the device shown is In one form of electron discharge devices com of the type adapted for the generation of ultra- 5 monly known as Barkhausen oscillators, the curhigh frequency oscillations and commonly known rent to the output electrode, which may be in as a Barkhausen oscillator. It comprises an the form of a grid and is at a positive potential evacuated enclosing vessel It having a reentrant relative to the cathode, comprises a. constant comstem II which terminates in a press l2. A pair ponent due to electrons which flow to this elecof bent or substantially inverted L-shaped Wires 10 trade directly from the cathode, and a variable l3 are embedded at one end in the press l2 and component due to electrons which flow to the have c red th a P Of Parallel resilient electrode after passing between the wires thereof metallic rods or members l4. A single linear andinto the region between this electrode and a. filament l5 of tanta um, tungsten other third electrode, which may be at zero or at a small terial having good electron emitting character- 5 negative potential, on the side of this electrode istics, is secured at its end to the rods i4 and remote from the cathode. It is desirable for eiliserves as-the cathode of the device. The heatcient operation, that the variable component be ing current for the cathode may be supplied a large part of the total current to the output through leading-in conductors it connected to electrode. the wires I3. 0

One object of this invention is to reduce the con- A bent wire H is embedded at one end in the stant component of the current to the output elecpress l2 and at the other end in an insulating trode in electron discharge devices and thereby to bead 18, the wire I! being disposed in a plane increase the efficiency of such devices. at substantially right angles to the plane of the.

In one embodiment of this invention, an elecwires l3. A metallic ribbon i9 is secured at one 25 tron discharge device of the Barkhausen oscilend to a rod 20 embedded in the insulating bead lator type comprises a cathode, an output elecl8, and at the other end to another rod 2| sealed trode including a plurality of parallel wires disin the end of the enclosing vessel as shown at 22. posed in a cylindrical boundary about the cath- The ribbon I9 is preferably flexible and bowed to ode, and a third electrode encircling the cathallow longitudinal expansion and contraction of 30 ode and the output electrode. the rods 20 and 2| with temperature variations.

In accordance with a feature of this invention, A cylindrical electrode 23 having a longitudinal the portions of the wires of the output electrode flange 24 is supported from rigid L-shaped wires directed toward the cathode and toward the 25 secured to the rod 20 and to the flange 24. A

5 third electrode are coated with an insulating mareenforcing rod or wire 60 may be secured on the terial, for example, beryllium oxide, so that no flange. The electrode 23 may be of sheet molybelectrons can flow in a linear path from the denum, the surfaces of which are roughened by cathode to the output electrode wires, or from the carborundum blasting to increase the heat rathird electrode to the output electrode wires, and diation therefrom, and is disposed about and oothe constant component of the current to the axially with the filament I5. 40 output electrode is thereby reduced. A bent wire 26 is embedded at one end in the The invention and the features thereof will be press l2 and carries an insulating bead 27. A understood more clearly and fully from the folbowed, flexible metallic ribbon 28, similar to the lowing detailed description with reference to the ribbon I9, is connected between a rod 29 emaccompanying drawing in which: bedded in the insulating bead 21 and a rod 30 45 Fig.v 1 is a perspective view of an electron dissealed in the enclosing vessel III as shown at 3l-. charge device of the general type comprehended A U-shaped wire or support 32 is secured to the by this invention, portions of the enclosing vesrod 29 and is rigidly held in position by braces or sel being broken away to show the internal strucrods 33 secured thereto and to the rod 29.

ture more clearly; An output 01'' grid electrode assembly'is carried 50 Fig. 2 is an enlarged detail view in longitudinal by the support 32 and comprises a pair of cylincross-section of the electrode structure of the drical metallic collars 34 connected to the arms device shown in Fig. 1; and of the support 32 by short, rigid wires 35, only one Fig. 3 is'an enlarged view of the cathode and of which is shown in Fig. 1. The collars 34 enoutput electrode as viewed from line 33 in Fig. circle the ends of the filament l5 and have secured thereto a plurality of equally spaced parallel wires 38, which may be of tungsten and are disposed parallel to the filament II and arranged in a cylindrical boundary coaxial with the filament.

In order to dissipate the heatirom the grid or output electrode, a pair of fins or annular discs 31 of relatively large area, and of a material having good heat radiating characteristics, for example, molybdenum or nickel roughened by carborundum blasting, are disposed adjacent the ends oi. the grid wires 36 and are thermally coupled thereto. The discs 31 may be disposed in contact with the collars 34 and may be connected to the collars by a plurality of bent wires 38 of good thermal conductivity.

The end portions 01' the filament ll within the collars 34 may be surrounded by tubular sleeves 3! of nickel or the like, secured to the rods ll by tabs 4|. The sleeves I! serve to substantially prevent the fiow of electrons to the collars and thereby confine the electrons emitted from the filament ii to paths embracing the wires I or the output electrode.

In utilizing the device described, for the generation of ultra-high frequency oscillations, thev grid or output electrode is operated at a relaJvely high positive potential with respect to the filament or cathode II, and the outer electrode 23 is operated at zero potential or at a low negative potential with respect to the filament or cathode.

Although the exact field conditions and electron action in the device during operation are not known with certainty, it is known that electrons emitted irom the filament or cathode travel outwardly from the filament or cathode under the influence of a positive potential on the grid or output electrode. some of the electrons pass directly to the wires 36 and impinge thereupon, while other 01' the electrons pass between the wires 3' into the region between the wires and the outer electrode II. Some or theglatter electrons may impinge upon the electrode 23, and, since this electrode is at a zero or at a negative potential, are repelled from the electrode and attracted to the wiresllandadsorbedthereby. Otherotthe electrons may be sufiiciently retarded by the positive potential on the output electrode, after they have passed into the region between the output electrode and the outer electrode 23, and may oscillate between the wires 10 beiore finally impin ins upon and being adsorbed by the wires I6.

From this it will be apparent, and experiments have substantiated the result, that the output current comprises at least two components, one of which is substantially constant and results from the electrons which fiow directly from the filament or cathode II to the wires 80 and 01' the electrons which pass to the wires 38 after being reflected from the electrode 23, and a variable or oscillatory component resulting from the electrons which oscillate between the wires 3 before finally impinging upon the wires and being adsorbed thereby. For emcient operation, it is desirable that the constant component of the output current be small and that the variable or oscillatory component of the output current be large. In accordance with this invention, a small constant component of the output current is insured by providing means substantially preventing the flow of electrons directly from the filament or'cathode I! to the wires 36 and directly from the outer electrode 23 to the wires. This insures the passage of a large number of the electrons one or more times between the wires 8 whereby a large variable or oscillating component in the output current is obtained.

In a specific embodiment of the invention, the surfaces 01' the wires 36 in radial alignment with the filament or cathode I5 and with the outer electrode 21 are covered with insulating coatings ll which prevent the adsorption by the wires It or those electrons which impinge upon the insulating coating and insure the passage of these electrons into the region between the wires 36. The coatings 4| are preferably of a material which is stable'at the temperatures extant in the device during operation and which will retain its insulating properties for an appreciable time. Beryllium oxide, for example has been found to be satisfactory, although other materials which meet the requirements set forth above may be used.

Although the invention has been described as embodied in a specific structure, it will be under-,

stood, 01' course, that it may be embodied equally well in structures of other designs without departing from the scope and spirit or the invention as defined in the appended claims. For example, the output electrode may comprise a plurality of circular wires encircling the cathode or it may comprise a helical wire disposed about the cathode and coaxial therewith. Portions of the circular wires or of the helical wire directed toward the cathode andtoward the outer electrode may be coated with an insulating material substantially the same as described in the specific embodiment oi the invention shown in the drawing.

What is claimed is:

1. An electron discharge device comprising an electron emitting electrode, an electron receiving electrode in cooperative relation with said first electrode, said electrodes being disposed one within the other, and insulating means intermediate all aligned portions of said electrodes for preventing the flow of electrons in a rectilinear path between said electrodes.

2. An electron discharge device comprising an electron emitting electrode, an electron receiving electrode in juxtaposition to said first electrode, and an insulating coating on all portions or said electron receiving electrode in alignment with said first electrode.

3. An electron discharge device comprising a cathode capable of emitting electrons when heated, an output electrode in cooperative relation with said cathode, and a coating of beryllium oxide on portions of said output electrode directed toward said cathode.

4. A Barkhausen oscillator comprising a cathode, an electrode in juxtaposition to said cathode, an electron receiving electrode intermediate said cathode and said first electrode, and insulating means adjacent said electron receiving electrode for preventing the fiow of electrons thereto in a rectilinear path from said cathode.

5. An electron discharge device comprising an electron emitting electrode, an electron receiving electrode, a third electrode outside 01' said elec-- tron receiving electrode, and an insulating shield intermediate said electron emitting electrode and all portions of said electron receiving electrode in alignment with said electron. emitting electrode.

6. An electron discharge device comprising a cathode, an electrode in juxtaposition to said cathode, a grid electrode having a plurality of spaced wires intermediate said cathode and said electrode, and an insulating coating on all the portions of said wires directed toward said cathode.

7. An electron discharge device comprising a cathode, an electrode in juxtaposition to said cathode, a grid electrode having a plurality of spaced wires intermediate said cathode and said electrode, and a coating of beryllium oxide on the portions of said wires directed toward said cathode.

8. An electron discharge device comprising an output electrode, a cathode on one side of said output electrode, an electrode on the opposite side of said output electrode, insulating means intermediate said cathode and said output electrode for preventing the flow of electrons in a rectilinear path from said cathode to any portions of said output electrode in alignment with said cathode, and additional insulating means between all aligned portions of said output electrode and said second electrode.

9. An electron discharge device comprising a cathode, an electrode in juxtaposition to said cathode, an output electrode intermediate said cathode and said electrode, and insulating shielding means intermediate juxtaposed surfaces of said cathode and said output electrode and of said first electrode and said output electrode, said means being disposed to prevent the flow of any electrons in a linear path from said cathode and said first electrode to said output electrode.

10. An electron discharge device comprising an output electrode, a cathode on one side of said output electrode, an electrode on the opposite side of said output electrode, and insulating coatings on all portions of said output electrode in align ment with said cathode and said second electrode.

11. An electron discharge device comprising a cathode, an outer electrode in cooperative relation with said cathode, a perforate electrode intermediate said cathode and said outer electrode, and coatings of beryllium oxide on portions only of said perforate electrode directed toward said cathode and said outer electrode.

12. An electron discharge device comprising a cathode, an electrode including a plurality of wires mounted in a cylindrical boundary about said cathode, and an insulating coating on portions only of said wires in radial alignment with said cathode.

13. An electron discharge device comprising a linear cathode, an electrode including a plurality of wires disposed parallel to one another and to said cathode and mounted in a cylindrical boundary about said cathode, and insulating shielding means between aligned portions ,of said cathode and said wires.

14. An electron discharge device comprising a linear cathode, an output electrode including a plurality of wires disposed parallel to one another and to said cathode, and mounted in a cylindrical boundary about said cathode, and an insulating coating on portions only of said wires in radial alignment with said cathode.

15. An electron discharge device comprising a linear cathode, a cylindrical electrode encompassing said cathode and coaxial therewith, an electrode including a plurality of spaced wires disposed parallel to one another and to said cathode and mounted in a cylindrical boundary intermediate said cathode and said cylindrical electrode and coaxial-therewith, and insulating shielding means intermediate radially aligned portions of said wires and said cathode and cylindrical electrode.

16. A Barkhausen oscillator comprising a linear cathode, an output electrode including a plurality of wires disposed parallel to one another and to said cathode and mounted in a cylindrical boundary coaxial with said cathode, a cylindrical electrode encompassing said cathode and said wires and coaxial with said cathode, and coatings of beryllium oxide on portions only of said wires in radial alignment with said cathode and said cylindrical electrode.

ARTHUR L. SAMUEL.

DISCLAIMER 2,000,990.-Arthur L. Samuel; Orange, N. J. ELECTRON DISCHARGE DEVICE. Patent dated May 14, 1935. Disclaimer. filed May 9, 1936, by the assignee, Bell Telephone Laboratories, Incorporated. Hereby enters this disclaimer to the subject-matter of claims 1, 4, 5, and 13 of said Letters Patent, to wit:

'. Your petitioner disclaims from the scope of claim-1 any electron discharge device as therein defined except such electron discharge device wherein the insulating means 18 in close proximity to the electronreceiving electrode and relatively remote from the electron emitting electrode. e

Your petition'erdisclaims from the scope of claim 4 any Barkhausen oscillator as therein defined except such Barkhausen oscillator wherein the insulating means is immediately adjacent and in contact with the electron receiving electrode.

Your petitloner disclaims from the scope of claim 5 any electron discharge device as therein defined except such electron discharge device wherein the insulating shield is disposed in immediate proximity to the electron receiving electrode and is carried thereby.

Your petitioner disclaims .from the scope of claim 13 any electron discharge device as therein defined except such electron discharge device wherein the insulating shielding means is in close. proximity to the wires of. the electrode and is supported thereby.

' [Oflicz'al Gazette June 2, 1986.]