Ode 3, 1946- ' H. c. THQMPSON ‘ 2,409,165 ELECTRON DISCHARGE DEVICE Filed Jan. 25, 1945 2 Sheets-Sheet l "III/Ill i - 0.‘? arrow/5y H. c. THOMPSON 2,409,165 ELECTRON DISCHARGE DEVICE Filed Jan. 25, 1945 2 Sheets-Sheet 2 IN VEN TOR. #91947 A’ 7i/0/77F5’0/7 BY Patented Oct. 8, 1946 2,409,165 UNITED STATES PATENT OFFICE 2,409,165 ELECTRON DISCHARGE DEVICE Harry C. Thompson, Princeton, N. J ., assignor to Radio Corporation of America, a corporation of Delaware Application January 25, 1945, Serial No. 574,472 9 Claims. 1 (Cl. 250-462) . 2 The invention covered herein may be manu factured and used by or for the Government of the United States for any governmental purpose Without payment to me or assigns of any royalty between which the beam is directed and by which the beam is de?ected. In the aperture assembly there are four ele ments which must be made with a high degree of thereon. precision to provide a successful device of the My invention relates to electron discharge de kind under consideration, particularly with ref vices, more particularly to such devices suitable erence to the maintenance of the dimensions and for use at ultra high frequencies and utilizing a alignment effecting these four elements. The beam of electrons which is periodically de?ected four elements of the apertured assembly include for varying the output current of the device. 10 two beam forming apertures, an electron lens, a Electron discharge devices to which the pres base for mounting the de?ection plates and a slot ent invention is directed are used as mixers and for locating the intercepting wires. A solid uni- ampli?ers, particularly at high frequencies Where .tary structure for determining the relationship the advantages of low input conductance and ca— between the above four elements is required. In pacity are important, 15 practice it was found, however, that the aperture One form of beam de?ection tube includes a openings varied and that the pressure to which cathode and associated elements for providing a directed beam of electrons of rectangular cross section, which beam is directed toward a collector through a beam focusing and beam de?ection 20 the elements were subjected caused variations which could not be tolerated and careful inspec tion and adjustment were necessary to bring system, the electron beam being de?ected across about the required accuracy. It is. therefore, an object of my invention to an apertured element to determine the amount of current to the collector. The aperture may be provide an electron discharge device of the type described in which greater accuracy of aperture bisected by a rod-like element, thus producing in width and of aperture alignment with cooperat eiiect a double aperture. Positioned between the 25 ing members can be had by inexpensive and prac collector and apertured element may be a sup tical means. pressor which may be aligned with the aperture A more speci?c object of my invention is to in the apertured element. make a device of the kind described in which the In the copending application of Charles W. aperture openings are made dependent upon and Mueller, Serial No. 561,339, filed November 1, 30 equal to just one readily controllable dimension of 1944, and assigned to the same assignee as the the structure. present application, there is shown and described A further object of my invention is to provide a beam de?ection tube of the general type de— such a device in which the aperture openings can scribed above. This tube utilizes a flat plate type be located automatically and symmetrically about of construction for insuring accurate alignment the mid-plane of the structure. I of the various electrodes. ‘In this arrangement A further object of my‘ invention is to provide a cathode provides a rectangular shaped beam of a structure of the kind described which eliminates electrons directed toward a collector. The beam the need for di?usion welding. focusing and de?ecting electrode system com A further object of my invention is to provide prises a pair of oppositely disposed plates, each 40 a device in which the number of parts is mini having a pair of rod-like elements welded to the mized and in which the processing can be made inside surface and extending transversely of the more routine. beam path. They are oppositely disposed from A further object of my invention is to provide each other to provide a pair of successively posi such a device in which a short radius of curvature 45 tioned apertures. To maintain these plates in of the aperture edges can be obtained,-thus im spaced relationship and to de?ne the rectangu proving aperture action. lar apertures, separating members extending par A still further object of my invention is to pro allel to the beam path and providing supporting vide a device of the kind described in which arms are positioned at the top and bottom of the changes of aperture openings can be made by plates. Each comprises three superimposed 50 one change in one element of the assembly. spacer elements, the middle one of which is A further object of my invention is to provide shorter than the other two to provide a ‘slot at such a device in which ?rst and second apertures a the end of the spacer element adjacent the col may be made of varying widths, and which can be lector. These longitudinally extending arms also less than the spacer thickness separating the support oppositely disposed de?ecting electrodes 5 apertured plates. , 2,409,165 3 A still further object of my invention is to pro vide such a device in which the aperture openings have the same mid-plane the spacer and the whole assembly, whereby the slot for the inter cepting wire and the deflecting plates subse quently located and positioned by the assembly legs are located symmetrically with respect to said mid-plane. The novel features which I believe to be char acteristic of my invention are set forth with par ticularity in the appended claims, but the inven~ tion itself will best be understood by reference to the following description taken in connection with the accompanying drawings in which Figure 1 is a side elevation with parts broken away to show i details of construction of an electron discharge device made according to my invention, Figure 2 is a transverse section taken along the line 2——2 of Figure 1 and showing a top view of the elec trode assembly, Figure 3 is a‘transverse section 20 taken along the line 2—3 of Figure 1, Figure 4 is an exploded perspective of the mount assem~ bly of the tube shown in Figures 1 to 3, inclusive. Figures 5 and 6 show details of construction of the aperture plate, Figure 7 shows details or" con struction of the de?ecting electrode assembly, Figures 8 and 9 show details of the spacer strip and Figures 10, 11 and 12 show partial sections of modi?cations of the aperture plate assembly. Brie?y, the device made according to my inven- 1 tion is housed within a non-magnetic metallic envelope provided with leads so that the device may be plugged into a proper socket or circuit. It includes a cathode assembly at one end of the envelope for providing a directed beam of elec trons and a collector at the other end of the en velope for receiving the electrons with a beam focusing and de?ecting electrode assembly posi~ 4 by the slot at the ends of the arms 21 and 26 as shown. Mounted at the end of the assembly is a pair of shields 32 and 33 which are supported by the header and are secured to the arms 25 and 21. These shields in turn support the apertured suppressor electrode 34 having the aperture 34’ by means of the glass bead assemblies such as 35 and 35'. A lead 35" is provided for the sup pressor. The end of the aperture and deflecting electrode assembly adjacent the cathode I2 is provided with a pair of transverse shield mem bers 48 and ill. These shield members provide a linear accelerating field for the electron beam and prevent stray electrons from striking the de ?ecting plates. Electrons from cathode 12 pass through the aperture l5’ through the aperture assembly 25 be tween the deflecting electrodes 28 and 2d and are deflected across the intercepting wire 30 passing through the aperture 34' to the collector 2| . The cathode end of the assembly is supported by the bracket 38’. A getter wire or trough 31 is mounted at the top of the envelope at the ends of the conductors and leads 38 and 39. A shield 38 is provided be tween the getter and the top of the electrode as sembly. The header is provided with a glass press 42 through which the leads 0,3 and 44 extend, these being in turn connected to de?ecting electrodes 29 and 28 by means of clips. The leads 43 and M extend parallel to each other through the press so that a coaxial line or Lecher wire system may be conveniently connected to the same externally of the envelope. The details of the aperture, lens and de?ecting electrode assembly are shown in Figures 4 to 6, inclusive. The aperture assembly comprises a pair of oppositely disposed U-shaped elements 50 tioned between the cathode assembly and col and Si having on their inner surfaces spring aper lector. ture elements to be described having ribs extend As shown in Figures 1 to 3, inclusive, the metal ing transversely of the beam path and toward each envelope ill of oval shape is provided with a me other to form apertures. These U-shaped ele tallic header ll through which the various leads ments are spaced by means of spacer elements 53 and supports for the electrodes extend, these leads being insulatingly sealed through the header 45 and 54 at the top and bottom of the assembly and will be described more in detail below. member. The envelope and header may be made of non-magnetic material such as stainless steel. Mounted within the envelope is a cathode elec Supported on the arms 25 and El are the de flecting electrode assemblies 28 and 29 including a mica element such as 55, reference being had to trode assembly comprising the indirectly heated cathode 12 provided with heater-cathode leads 50 Figure 7, including tabs or ear-like extensions such as 45 and ll? at its ends. A spacer element l3 and ill. The cathode is surrounded by means is mounted in contacting relationship with the of the shielding member l5 having a front cover mica and a thin foil 49, preferably gold, wrapped member I6 provided with elongated aperture around these elements to provide the deflecting 16' through which the electrons from the cathode l2 are directed. This electrode assembly is 55 electrode. The wrapped foil produces a smooth lens edge eliminating any burrs. These deflect mounted between a pair of insulating spacer ing electrodes are assembled on the arms 26 and members I‘! and i3 and clamped to the same by 2‘! so that the tabs or lugs, such as 46 and 4'5 means of the strap l5 and positioned between the register with the arms and are secured thereto micas by means of the ears such as 29-2ii'. Mounted at the other end of the envelope is a 60 by straps such as 28’ fastened by welding, for collector 2! in the form of a 1001?) supported by means of the support and lead 22. F example, to the arm. The aperture plate as sembly and de?ecting electrodes provide an elec tron lens as described in a co-pending application Positioned between the cathode and the col of George Ross Kilgore, Serial No. $12,625 ?led lector is the aperture, lens and beam de?ecting electrode assembly. The aperture, lens and beam 65 June 27, 1940 and assigned to the same assignee as the present application. This construction de?ecting electrode assembly is formed as a unit eliminates any surfaces between the de?ecting and includes the aperture portion, designated electrodes and the intercepting wire and on which generally at 25 and which will be described in any surface charges could exist. greater detail below, provided with horizontally Because all parts are held against flat surfaces extending arms 26 and 2'! which support the de 70 tilting of electrodes is avoided. The aperture ?ecting electrodes 23-29 and the intercepting plate ‘assembly is simple to make and the lens wire 30 anchored at its lower end and maintained edge easier to control. in tension by means of the spring anchor SI per The aperture assembly made according to my mitting expansion and contraction of the wire but always assuring alignment. The wire is guided 75 invention is shown in greater detail in Figures 5 2,409,165 5 6 and 6. In accordance with my invention, I pro vide a pair of elongated U-shaped elements 50 in producing a tube which functions in the de siredv manner. While I have indicated the preferred embodi ments of my invention of which I am now aware offset portion, such as 55 and 55'. Spot welded and have also indicated only one speci?c applica to the inside surfaces of these portions are the tion for which my invention may be employed, spring aperture elements 56 and 51 provided with it will be apparent that my invention is by no spring ribs 58 and 59, 6!! and (ii. The U-shaped means limited to the exact forms illustrated or members and 5| are separated by means of the use indicated, but that many variations may separator elements 53-54 which are provided with lugs, such as 5G’ and 53’, which extend down 10 be made in the particular structure used and the purpose for which it is employed without depart between and separate the spring members 56 and ing from the scope of my invention as set forth in 51, the rib portions 58 and 59, 50 and 6! contact the appended claims. ing the opposite surfaces of the lug, thus deter What I claim as new is: mining the width of the opening of the aperture 1. An electron discharge device having a cathode formed by the ribs. The inserts are so dimen 15 means for supplying electrons, and an electrode sioned that the ribs are held against the spacer in the path of said electrons, and beam de?ning lugs and spring tensioned. In practice these means positioned between said cathode means apertures may be .004 inch and the die-formed and said electrode and through which the path spring members may be formed from rectangular blanks of sheet Nichrome .002 inch thick. As 20 of the beam of electrons lies, said beam de?ning means including a pair of oppositely disposed shown in greater detail in Figure 10 the portion conducting members spaced apart to provide a between the ribs is formed ?at and parallel to the ribs to permit proper seating in the recess portion passageway therebetween, registering spring-like 55, for example, of the U-shaped elements. The elements mounted on said conducting members and having ribs extending transversely of the ribs of the insert are thus supported on portions offset from the web and these portions consti beam path on opposite sides of the beam path, tute ?exible members or springs carrying the ribs. and extending toward each other to provide an The aperture openings as above described are, aperture therebetween, and means at opposite therefore, substantially equal to the lug thickness edges of said spring-like elements for maintaining and are independent of variations of two or three ‘ said ribs in spaced relationship for positively de thousandths of an inch in the dimensions of other termining the aperture width. parts. Thus the correctness‘ of the aperture 2. An electron discharge device having a cathode and 5 I, each of which is provided with a recess or opening within a few ten-thousandths of an inch depends upon one easily controlled dimension, namely the lug thickness, while the dimensions means for supplying electrons, and an electrode in the path of said electrons, and beam de?ning means positioned between said cathode means and said electrode and through which the Path of the beam of electrons lies, said beam de?ning means of the other parts may be held only to the ordi nary tolerances of tube manufacture. By the arrangement shown in Figure 10, for including a pair of oppositely disposed conduct example, the spacer member 65 may have two ing members spaced apart to provide a passage recessed portions permitting the width of the 40 way therebetween, registering spring-like ele apertures to be less than the width of the spacer ments mounted on said ?at surfaces and having and also to have different widths. For this pur elongated ribs extending transversely of the beam pose the spacer may be provided with coined de path on opposite sides of the beam path and ex pressions in its lug with which inserts cooperate. tending toward each other to provide an aperture In Figures 8 and 9 are shown the method em 45 therebetween. ployed for manufacturing a coined spacer. A 3. An electron discharge device having a cathode continuous strip of thin metal 65, shown ?atwise means for supplying a beam of electrons and an in Figure 8 and edgewise in Figure 9, has narrow electrode in the path of said electrons, and a beam depressions 66 and B7 stamped or coined across de?ning and de?ecting means positioned between it at predetermined intervals so that, when the 50 said cathode means and said electrode and strip is cut along the dotted lines, spacers, each through which the path of the beam of electrons with two embossed depressions in its lug, are passes, said beam de?ning and deflecting means formed therefrom. The order of procedure is including a pair of oppositely disposed elongated important. The coining of the depression is done U-shaped members, spring inserts mounted at the after the strip is cut to width whereby the cutting 55 closed end of said U-shaped members and having burrs at the inner edge of the lug are coined ribs extending transversely of the beam path and down so as not to interfere with the seating of toward each other to provide an aperture through the insert ribs against the bottoms of the coined which the beam path passes, and means carried depressions. by said U-shaped members and extending be In Figures 11 and 12 are shown alternate forms 60 tween said spring inserts for maintaining said ribs of rib-bearing spring inserts in relation to sec in spaced relationship for determining the width tions of the U-part webs appropriate thereto. of the aperture between said ribs. In Figure 11 for example the spring elements 5'?’ 4. An electron discharge device having a cathode and 58’ have their lugs extending through aper means for supplying a beam of electrons and an tures provided in the U-shaped members 50 and 65 electrode in the path of said electrons, and a beam 5|’ and abut the spacer 65’. In Figure 12 as in defining and de?ecting means positioned between Figure 11 the ribs of the aperture elements 58" said cathode means and said electrode and through which the path of the beam of electrons and 57" merely constitute the turned up edges of the spring which abut directly on the spacer lies, said beam de?ning and de?ecting means in 70 cluding a pair of oppositely disposed elongated element 55'. U-shaped members, the legs of which lie parallel Thus with my improved form of device I ac to the beam path, spring inserts mounted at the complish the objects enumerated above in a sim closed end of said U-shaped members, each hav ple and effective manner, reducing the parts re ing a pair of ribs extending transversely of the quired, the operations required and insuring greater accuracy of the various elements involved 75 beam path, the ribs of each pair registering with 2,409,165 7 8 the opposite pair of ribs and providing a pair of U-shaped elements, the closed ends of which are positioned adjacent the cathode and the ends of the legs of which are positioned adjacent the electrode, said U-shaped members having offset 5. An electron discharge device having a cathode means for supplying a beam of electrons and an b portions providing recesses in the closed end thereof and spring-like inserts mounted within electrode in the path of said electrons, and a beam said recesses, each or said inserts having a pair de?ning and de?ecting means positioned between apertures successively positioned along the beam path. ‘ said cathode means and said electrode and through which the path of the beam of electrons of ribs extending transversely of the beam path and toward the opposite pair and providing a pair passes, said beam de?ning and de?ecting means 10 of successively positioned apertures, and spacer including a pair of oppositely disposed elongated U-shaped members, the legs of which lie parallel members clamped between oppositely disposed legs or said U-shaped member for spacing said U -shaped members and each provided with a lug to the beam path, spring inserts mounted at the extending between and in contact with said op closed end of said U-shaped members and having -- itely disposed pairs of ribs of said spring-like ribs extending transversely of the beam path and sarts for determining the aperture width be in registry with each other to provide an aperture, en said ribs. said spacer members being and spacing means carried by said U-shaped shorter than the legs of said U-shaped members members, said spacing means including spacer and providing slots, and a rod-like element posi elements between the legs of said U-shaped mem bers for maintaining said U-shaped members in 20 tioned within said slots, and deflecting electrodes mounted between each pair of legs of each U spaced relationship and each having a lug inter shaped member and on opposite sides of the beam posed between the ribs of said spring inserts and path for de?ecting the electron beam. in contact with the ribs for maintaining a pre 8. An electron discharge device having cathode determined spacing bctween said ribs for deter means for supplying a beam of electrons, and an mining the width of the aperture between said electrode in the path of said electrons, and a beam ribs. de?ecting electrode assembly positioned between 5. An electron. discharge device having a cathode means for supplying a beam of electrons and an said cathode means and said electrode and electrode in the path of said electrons, and a beam de?ning and de?ecting means positioned between said cathode means and said electrode and through which the path of the beam of elec through which the beam path lies and including a pair of oppositely disposed members, spring-like inserts supported on said members, each having a pair of ribs extending transversely of the beam _ trons passes, said beam de?ning and deflecting path, the ribs on one insert extending toward the ribs on the other and providing a pair of succes means including a pair of oppositely disposed elongated U-shaped members having legs extend sively positioned apertures and spacers positioned between said oppositely disposed members and ing parallel to the beam path, spring inserts having portions of di?erent thicknesses positioned mounted at the closed end or” said U-shaped between each pair of oppositely disposed ribs at members and having registering ribs extending the ends thereof, whereby the aperture Widths transversely of the beam path and providing an aperture, spacing means carried by said U 40 differ from each other. An electron discharge device having cathode shaped members including spacer elements be means for supplying a beam of electrons, and an tween said legs for maintaining said U-shaped electrode in the path of said electrons, and a beam members in spaced relationship and having a d iecting electrode assembly positioned between lug interposed between the ribs of said spring in said cathode means and said electrode and serts and in contact with the ribs for maintaining through which the beam path lies and including a predetermined spacing between said ribs for a pair of oppositely disposed conducting members determining the width of the aperture between having ?at surfaces, spring-like inserts supported said ribs, said spacing elements being shorter on said ?at surfaces, each having a pair of ribs than the legs of said U-shaped members whereby extending transversely of the beam path, the ribs a slot is provided at the ends of the legs of said U-shaped members and a rod-like element re ceived’ within said slot. 7. An electron discharge device having cathode means for supplying a beam of electrons and an electrode toward which said beam of electrons is directed, a beam focusing and de?ecting electrode assembly positioned between said cathode means and said electrode and through which the beam path extends and including a pair of elongated on one insert extending toward the ribs on the other and providing a pair of successively posi tioned apertures and a spacer positioned between said conducting members and having portions of different thicknesses positioned between each pair of oppositely disposed ribs at the ends thereof, whereby the aperture widths di?er from each other, HARRY C. THOMPSON.