US2161005A - Electron discharge device - Google Patents

Description

June 6, 1939.

C. A. BIELING ELECTRON DISCHARGE DEVICE Filed Sept. 4, 1937 III /NVEN TOR C14.B/EL//VG AT TORNEY Patented Junefi, 1939 t UNITED STATES PATENT OFFICE 2,161,005 ELECTRON DISCHARGE DEVICE Carl A. Bieling, Westfield, N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 4, 1937, Serial No. 162,418

7 Claims. (01. 250-275) This invention relates to electron discharge features thereof will be understood more clearly devices and more particularly to such devices esand fully from the-following detailed description pecially suitable for the generation and amplifiwith reference to the accompanying drawing, in cation of ultra-high frequency impulses. which One object of this invention is to expedite the Fig. 1 is an elevational view in perspective of 5 fabrication of electron discharge devices and esan electron dischar dev e st u ted in acpecially such devices having a plurality of grid cordance with this invention, portions of the enelectrodes. closing vessel and of the electrode structure being Another object of this invention is to maintain broken away to show details of construction more accurately the desired form and geometrical disclearly; 10 position of the electrodes inelectron discharge de- 2 is a lo di a sec ional View Of the vices. 1 electrode assembly embodied in the device shown A further object of this invention is to obtain n substantially uniform electron distribution from Fi 3 is a lateral ect nal V ew f t e electhe cathode of electron discharge devices. trodes in the device shown in Fig. 1 along lines 15 Still another object of this invention is to inof i illustrating h m and p icrease the power capacity of electron discharge tiOn thereof and showing the eXtent 0f e t erdevices having closely spaced electrodes. m n c Coating po the de;

In one illustrative embodiment of this inven- Fig. 4 is an enlarged detail view in section illus- 2 tion, an electron discharge device comprises a trat t e a soc at o a d and a ati cathode, an anode encompassing the cathode, one spacerin the device rat in F or more cylindrical grids disposed between the 5 is a perspective View illustrating a medicathode and the anode, and insulating members fied grid constructed in accordance with this inat opposite ends of and spacing the several elec- Vention; and

trodes, Fig. 6 illustrates a method of fabricating grids 25 The grids may be formed of sheet metal tubing, in accordance with this invention. for example tubing of tungsten, tantalum or mo- Referring now to the drawing, the electron dislybdenum, portions of the tubing being removed, charge dev shown in 1 Comprises a enas by abrasive wheels, to form'a plurality of parclosing vessel n h v n an inwardly ex ndin 3o allel circular grid elements integral with one or stem II that terminates in a press l2 fromwhich o more supporting or upright portions, The insuthe electrodes are supported. A suitable base, l3, lating spacer members are provided with concenfor example of insulating material, is secured to tric annular grooves for receiving the ends of the enclosing vessel and carries a plurality of the grids. terminal prongs or pins l4 through which elec-' 5. In accordance with one feature of this inventrical connection to the electrodes may be estabtion, the insulating spacer'members are positioned lished. by the anode and means are provided for resil- A unitary electrode assembly is supported from iently holding one of the insulating members the press l2 and comprises a central cathode, a against the grid or grids so that the grid or grids plurality of grids l5, l6 and H, a cylindrical an- 40 may expand and contract freely in a longitudiode I 8, and insulating spacer members or discs 40 nal direction. I9 and 20 at opposite ends of the electrodes. As

In accordance with another feature of this inillustrated in Fig. 3, the several electrodes prefvention, the annular grooves in the insulating erably are arranged concentric with one another. spacers are V-shap'ed in section so that lateral The innermost grid l5 may be utilized as the shifting of the grid or grids is prevented and control electrode, the next grid l6 as a screen or 5 accurate spacing and alignment of the electrodes shield electrode and the outermost grid I! as a is thereby maintained. suppressor electrode.

In accordance with still another feature of this Each of the grids is a rigid, self-sustaining unit invention, only those portions of the cathode efimplising a plurality of Parallel circular opposite the reticulated portions of the grid nearmerits 2| joined by and integral with diametrically 5 est the cathode are coated with thermionic maopposite supporting or upright portions 22. As ilterial whereby a uniform electron distribution lustrated in Fig. 6, the grids may be formed of through the reticulated portions of the grid is sheet metal tubing 60 held in suitable clamps 61, obtained. portions of the tubing being removed by paral- The invention and the foregoing and other 1e1 abrasive wheels 23, the width of which determines the spacing of the circular elements 2! and the spacing of which determines the size of the elements 2!. Any burrs formed by the abrasive grinding may be removed by a bufiing operation. Grids thus constructed, it will be apparent, may be manufactured expeditiously in quantity and at low cost. Such grids, furthermore, obviate the use of welds in the grid structure and thereby allow the use of materials such'as tungsten, tantalum and molybdenum having high melting points. Consequently, grids constructed as above described may be operated at high temperatures and the devices of which they form a part are capable of handling large powers.

As shown clearly in Fig. 2, the anode is provided at one end with an inwardly extending flange 2d upon which the insulating spacer member or disc 59 is seated. This insulating spacer I9 is provided with concentric annular grooves in each of which a corresponding one of the grids i5, i6 and ii is seated. The other insulating spacer member or disc 20 is slidably fitted within the anode i8 and, similarly to the member i9, is provided with concentric annular grooves 25 for receiving the grids, It is held in intimate engagement with the several grids by a resilient, annular, dished metallic member or spring 23 which is held in position by an inwardly extending flange 2'! on the anode. The spring member 26,

it will be seen, allows longitudinal expansion and contraction of the grids, occasioned by temperature variations therein during operation of the device, so that the cylindrical form of the several grids is preserved. By its action, however, the spring member 26 holds the insulating disc 20 in contact with the several grids so that the grids are held in spaced relation.

As shown clearly in Fig. 4, the grooves 25 preferably are V-shaped in section so that the two surfaces thereof engage opposite edges of the grids. Hence, lateral shifting of the grids is prevented and the requisite spacings between the grids and the cathode and anode are accurately maintained. This, it will be appreciated, is highly desirable in ultra-short wave devices, wherein the electrode spacings not only are very small but also must be accurately constant during operation of the device to assure uniform electron transit times and constant operating characteristics.

The cathode may be of the equipotential type and comprises a cylindrical metallic sleeve 28 extending through aligned central apertures in the insulating discs l8 and 20 and frictionally engaged by chamfered edges 29. Disposed within the cathode sleeve 28 and insulated therefrom by a ceramic body 62 is a suitable heater filament 39. The cathode sleeve 28 has thereon coatings 3! of a thermionic material, such for example as barium and strontium oxides. As shown clearly in Fig. 3, the portions 32 of the cathode sleeve 28 in the shadow of the supporting or upright portions 22 of the control grid !5 are not coated with thermionic material so that concentration of electrons adjacent the supporting or upright portions 22 is prevented and a uniform dispersion of electrons through the control grid i5 is obtained.

The unitary electrode assembly above described may be supported from the press 12 by a pair of rigid supports 33 embedded in the press and afiixed, as by welding, to the anode I8, one of the supports being connected electrically to a corresponding one of the terminal prongs I4 by a conductor 34.

One of the supporting or upright portions 22 of each of the grids may be extended through and below the lower insulating spacer l9, as shown clearly in Fig. 2, and have afllxed thereto a leading-in conductor 35, each of which is electrically connected to a corresponding one of the terminal prongs M. Electrical connection to the cathode may be established by a suitable con-- ductor 36 afixed to the cathode sleeve 28 and heating current for the filament 30 may be supplied through conductors 31.

It will be understood that each of the several grids may be utilized to perform one of a number of functions. If desired, the grid utilized as the control electrode may be provided with a leadingin conductor extending through a suitable aperture in the ring member 26 and sealed in the vessel it at the top thereof, to minimize the capacitance between this grid and the other electrodes.

As shown in the drawing, the circular portions 2! of the several grids may be in alignment and of the same thickness. For example, these portions may be of the order of 5 mils in thickness and may be spaced of the order of 10 mils. Of course, the portions 2! of the several grids need not be in alignment and, if desired, these portions of each grid may be spaced non-uniformly to provide variable rnu characteristics.

As illustrated in Fig. 5, each of the grids i5, i6 and i! may have but a single supporting or upright portion 22.

Although specific embodiments of the invention have been illustrated 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 defined in the appended claims.

What is claimed is:

1. An electron discharge device comprising a plurality of cooperatively disposed electrodes, an insulating member spacing said electrodes at one end, a second insulating member spacing said electrodes at the other end, and resilient means bearing against said second insulating member for urging it toward said first insulating member.

2. In an electron discharge device, an electrode assembly comprising an insulating spacer having a plurality of annular grooves therein, a plurality of rigid tubular electrodes each seated at one end in a corresponding one of said grooves, an insulating member engaging said electrodes at the other end thereof, and means including a resilient member for holding said spacer and insulating member in engagement with said electrodes.

3. In an electron discharge device, an electrode assembly in accordance with claim. 2 wherein said annular grooves are V-shaped in section.

4. In an electron discharge device, an electrode assembly comprising a rigid electrode having a flange at one end thereof, a spacer member seated upon said flange, a second electrode seated at one end upon said spacer member, and means including a resilient member positioned by said first electrode and engaging the other end of said second electrode for holding said second electrode in engagement with said spacer member.

5. In an electron discharge device, an electrode assembly comprising a hollow anode having flanges at the ends thereof, an insulating spacer seated upon one of said flanges, an electrode within said anode and seated upon said insulating spacer, an insulating member slidably mounted within said anode and engaging said electrode, and resilient means engaging the other of said upon one of said flanges, said disc having a plurality of concentric annular V-shaped grooves therein, a plurality of coaxial tubular grids having one end seated in said grooves, a second insulating disc slidably fitted in said anode and 5 engaging the other end of said grids, said second insulating disc having concentric, annular, V-shaped grooves for receiving the other end of said electrodes, and an annular resilient member between and engaging said second disc and 10 the other flange on said anode.

CARL A. BIELING.

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