Oct. 15,1946. " 5. w. HEROLD 2,4@9,485 ELECTRON DISCHARGE DEVICE i-"ned Jan. 24, 1945 2 Sheets-Sheet 1 ./ INVENTOR. HERWD 2,409,485 E w H s RQL D ELECTRON mscmmus DEVICE Filad Jan. 24, 1945 I z‘sheets-shaat 2 INVENTOR. +300 EDWARD W. HEROLD-I @www ATTORNEY 2,409,485 Patented Got. E5, 3946 _ er ‘I: B. ". - i vPATENT OFFICE 2,d09,d85 EEECTRON DISCHARGE DEVICE Edward W.',Eerold, ‘Kingston, N. 3., asslgnor to Radio Qorporation of America, a corporation of Delaware 1 Application January 24, 1945, Serial No. 574,263 7 Glalma. (171. 315-717) l 2 The invention covered herein may be manufac tured and used by or_ for the Government of the United States for' any governmental purpose normal standards some require adjustment by means of correcting magnets. Although some of the trouble was probably due to surface poten tial variations on various parts of the electrode mount, other dimculties appeared to be due to without payment tome or assigns of any royalty thereon. My invention relates to electron discharge de misalignment of the tube elements. In this re~= vices, more particularly to such devices suitable spect, de?ection plates, which also comprise part for use at ultra high frequencies and utilizing a of the main electrostatic focusing lens, present beam of electrons which is periodically de?ected the greatest problem since their alignment is for varying the output of the device. 10 critical, and possibly are ‘the chief cause of sub Electron discharge devices to which the pres‘ standard operation, and yet alignment can be ent invention is directed are used as mixers and maintained only by extreme care in mounting. ampli?ers, particularly at high frequencies where It was believed'the chief disadvantages of de the advantages of low input conductance and ca ?ection plate misalignment could be overcome pacity are important. - " 15 if these plates were operated at the same poten- , One form of beam de?ection tube includes a . cathode and associated elements for providing a directed beam of electrons of rectangular cross section, which beam is directed toward a col lector through a, beam ‘focusing and beam de?ec 20 tion system, the electron beam being de?ected tial as surrounding electrodes, since then no electric ?elds would be present to distort the beam in case of misaligned parts. However, in this event focusing of the beam, which is essen tial in a tube whichlis to have high sensitivity, must be done in some other way. across an apertured element to determine the In the present type of beam de?ection tube ‘ ' amount of current to the collector. The aperture the centering of the beam is accomplished by a may be bisected by a rod-like element, thus pro differential bias applied'to the de?ecting elec ducing in effect a double aperture. Positioned 25 trodes. This requires troublesome blocking con between the collector and apertured element may densers and D.-C. separation of the de?ection be a suppressor which is aligned with the aper plates. The de?ecting electrodes are also relied ture in the apertured element. upon in combination with the apertured ele In the copending application of Charles ‘W. ments to provide a focusing action on the elec-_ Mueller, Serial No. 451,339 ?led November 1, 1944, 30 tron beam, thus necessitating the use of the de and assigned to the same assignee as the present ?ection plates for two functions with the at-, application, there is shown and described a beam tendant mechanical and electrical dimculties. de?ection tube of the general type described It is, therefore, a. principal object of my inven- . above. This tube utilizes a ?at plate type of tion to provide an electron discharge device of construction for insuring accurate alignment of v 35 the beam de?ection type of improved design in the various electrodes.‘ In this arrangement a ‘which normal performance can be substantially cathode provides a rectangular shaped beam of assured. . electrons directed toward a collector. The beam Another object of ‘my invention is to provide focusing and de?ecting electrode system 'com such a device in which the disadvantages of prises a pair of oppositely disposed plates,,each 40 misalignment of de?ection plates are eliminated. having a pair of' rod-like elements welded to the or reduced to a minimum. inside and opposing surfaces of the plates, and ex Another object of my invention is to provide tending transversely of the beam path. They are . an electron discharge‘ device of the beam de?ec oppositely disposed from each other to provide a ' tion type having an electrode system in which no pair of successively positioned apertures. To 45 bias is needed on the de?ection plates so as to maintain these plates in spaced relationship and eliminate the troublesome blocking condenser to de?ne the rectangular apertures, separating and D.-C. separation of the de?ection plates. A further object of my invention is to provide ‘ members, extending parallel to the beam path an electron assembly in which the focusing and and providing supporting arms, are positioned at the top and bottom of the plates. These lon 50 de?ection portions can be separated whereby gitudinally extending arms also support opposite tubes can be built which will have better elec tron beam alignment on the average than previ ly disposed de?ecting electrodes between which ously obtained. the beam is directed and by which the beam‘ is deflected. The novel features which I believe to be char— While many tubes of this type perform up to 55 acteristic of my‘invention are set forth with par 2,409,485 . exploded perspective showingv the arrangement ' between the de?ecting electrodes 28 and 29 and are deflected across the intercepting wire 30 pass an elevation of an electron discharge device made according to my invention with parts re moved to show details of construction, Figure 2 is a transverse section taken along the line 2-2 of Figure 1, Figure 3 is a transverse section taken along the line 3-3 of Figure 1, Figure 4 is an 4 aperture l6’ through the aperture assembly 25 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 10. ing through the aperture 34’ of suppressor 34 .to the collector M. 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 36 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 43 and 44 extend, these of the parts 'of a mount assembly of the electron being in turn connected to de?ecting electrodes discharge device shown in Figures 1 to 3 inclu 29 and 28. The leads‘ 43 and 44 extend parallel sive, Figures 5, 6 and 7 show details of construc to other through the press so that a coaxial tion of the focusing portion of the assembly made 15 lineeach or Lecher wire system may be conveniently according to my invention, and Figure 8 is a _ connected to the same externally of the enve schematic diagram showing the lens effect pro lope. duced by the arrangement shown in Figures 5, .The details of the aperture and focusing ar 6 and 7. As shown in Figures 1 to 3 inclusive, the evac uated metal envelope in of oval shape is pro vided with a metallic header 1 i through which rangement made according to my invention are shown in Figures 5, 6 and '7. This assembly in cludes a pair of plate members such as 50 and Ii having rectangular apertures such as 50'. These the various leads and supports for the electrodes plates are oppositely disposed to each other and extend, these leads being insulatingly sealed are maintained in spaced relation by arms 28 through the header member. The envelope and 25 and 2'! as described above. Adjacent the oathheader may be made of non-magnetic material ode side of the plates and mounted on the inner such as stainless steel. ' opposed surfaces .of the plates are a plurality of Mounted within the envelope is a cathode elec ‘rod-like elements 52, 53, 54 and 55. These ele trode assembly comprising the indirectly heated ments may be secured to the inner surfaces of cathode i2 provided with the cathode and heat 30 the plates by fusion welding, for example, and er-leads l3 and I4. The cathode is surrounded oppositely disposed to each other to provide a by means of the shielding member i5 having a front cover member 16 provided with an elon pair of successively positioned apertures through which the beam of electrons is directed. Mounted over the apertures, such as 50', in from the cathode l2 are directed. This electrode 35 these apertured plates are a pair of mica mem assembly» is mounted between. a pair of insulat bers 51 and 58 upon which and registering with ing spacer members I’! and I8 and clamped to ‘the apertures are’ focusing electrode members the same by means of the strap i9 and positioned 55 and 56, which are provided as best shown in between the spacer members which may be mica Figures 2 and 3 with leads 55' and 5B_' for permit gated aperture l6’ through which the ‘electrons by ‘means of the ears such as 20-40’ on member 40 ting the application of proper biasing voltages. it. Mounted at the other end of the envelope is _ As shown in Figure 8 by applying a low or zero a collector 2| in the form of a loop supported by potential to the focusing plates 55 and 5B and a means of the support and lead 22. high positive potential, for example in the neigh Positioned between the cathode and the col lector is the aperture, lens and beam. de?ecting 45 borhood of 300 volts, to'the apertured plates 50 and ii, a lens effect may be produced as indi electrode assembly. The aperture, lens and cated. The de?ecting electrodes may also be beam de?ecting electrode assembly is formed as maintained at a high positive potential, for ex ample 300 volts, whereby no D.-C. potential dif tion, designated generally at 25 and which will be described in' greaterdetail below, provided 50 ference exists between the apertured plates and the deflecting plates, the focusing electrodes with horizontally extending arms 26' and 21 being utilized also as centering electrodes by a -which support the de?ecting electrodes 28, 29 biasing voltage differential ,on these two plates and the intercepting wire 30 anchored at its lower _ a unit and includes the aperture and lens por end and maintained in tension by means of the spring anchor 3| permitting expansion and con traction of the wire but always assuring align ment. The wire is positioned in and guided by the slots 26' and 21' at the ends of the arms‘ 26 and 21. Mounted at the collector end of the assembly is a pair of shields 32 and 33 which are supported by the header'and are secured to the arms 26 and 21. These shields in turn sup- port the apertured suppressor electrode 34 having the aperture 34' by means of the glass bead as- if this is necessary. Thus with my arrange 55 ment the electron beam starts from the cath ode, is accelerated by the 300 volt aperture-plate potential and then passes through two fine col limating apertures formed» by the rods on the aperture plate. Instead of entering the de?ect 60 ing electrode region, the beam then passes through‘ an electrostatic lens region formed by the rec tangular apertures in the'aperture-plates and the ' focusing electrodes. The correct focal length is given this lens by means of adjustment of the _ semblies such as 35 and 35'. A lead 34" is pro 65 potential on the focusing electrodes. In a prop erly designed device this potential can be made vided for the suppressor. The end of the aper . zero, so that the only potentials on the tube are ture and de?ecting electrode assembly adjacent zero and the accelerating voltage. The tube then the cathode I2 is provided with a pair oftrans becomes inherently a fixed focusing device in verse shield members 40 and M. These shield members provide a linear accelerating ?eld for 70 dependent of the applied accelerating voltage. the electron beam and prevent stray electrons _ from striking the de?ecting plates. The cath ode end of the assembly is supported by the bracket 38'. , “ The principle utilized here is described by H. Iams in the Proceedings of the I. R. E., volume 27, pages 103-105, February 1939. While I have indicated the preferred embodi Electrons from cathode 12 pass through the 75 ments of my invention of which I am now aware 5. 2,409,4135 and have also indicated only one speci?c appli cation for which my invention may be'employed, it will be apparent that my invention is by no 'means limited to ‘the exact forms illustrated or the use indicated, but that many variations may be made in the particular structure used and the 6 for providing an aperture between said cath ode means and said focusing electrodes, said means on the facing surfaces of said plates in cluding rod-like elements extending transverse ly of the beam path. . ‘ 5. An electron dischargedevice having cath purpose for which it is employed without depart- , ingfrom the scope of my invention as set forth ode'means for supplying a beam .of electrons, and an electrode in the path of said electrons, an electron lens assembly positioned between said What I claim as new it: 10' cathode means and said electrode and through 1. An electron discharge device having a cath which the path of the beam of electrons lies, said ode means for supplying a beam of electrons and lens assembly including a pair of plate members an electrode in the path of said electrons, and having oppositely disposed ~apertures . therein, means positioned between said cathode means means for maintaining said plate members in and said electrode and including an electron lens spaced relationship, focusing electrodes mount , in the appended claims. system comprising oppositely disposed apertured plates adapted to have a biasing potential ap plied thereto and between which the beam path extends, and electrode elements mounted in reg istry' with said apertures on the outside of and out of contact with said plates and adapted to have a lower biasing potential applied thereto than to said plates. 2. An electron discharge device having a cath ed on the outside surfaces of said plate mem bers and insulatingly supported thereon in reg istry with said apertures, a plurality of pairs of oppositely disposed rod-like elements positioned on the facing surfaces of said plate-like members ' and positioned between the cathode and the aper tures for providing a pair of successively posi tioned apertures. ' 6. An electron discharge device having cathode ode means for supplying a beam of electrons and 25 means for supplying a beam of electrons, and an an electrode in the path of said electrons, and means positioned between said cathode means and said electrode and including an electron lens system comprising oppositely disposed apertured plates adapted to have a biasing potential ap plied thereto and between which the beam path extends, and electrode elements mounted in reg-. istry with said apertures on the outsideof and;v out of contact with said plates and adapted to " electrode in the path of said electrons, an} elec tron lens assembly positioned between said cath ode means and said electrode and through which the path of the beam of electrons lies, said lens assembly including a pair of plate members hav ing oppositely disposed apertures therein, means for maintaining said plate members in spaced relationship and including a pair of elongated‘ members extending from one side thereof, focus ing electrodes mounted on the outside surfaces of said plate members and insulatingly supported thereon in registry with said apertures, and a have a low biasing potential applied thereto than to said plates, and a pair of de?ecting electrodes between said lens system and said electrode and between which the path of said electrons lies. ‘ plurality of pairs of oppositely disposed rod-like 3. An electron discharge device having cath “elements positioned on the facing surfaces of ode means for-supplying a beam of electrons and 40 said plate-like members and positioned between an electrode in the path ‘of said electrons, and ‘the cathode and the apertures for providing ‘a means positioned between said cathode means and said electrode and including an electron lens pair of successively positioned apertures, and de ?ecting electrodes mounted on said elongated members between said focusing electrodes and the electrode in the path of said electrons. system comprising a pair of oppositely disposed plate-like members having registering apertures 45 and spaced apart and between which the beam ' '7. An electron discharge device having cath path lies, focusing electrodes insulatingly sup - ode means for supplying a beam of electrons, and ported on the outside of said plates in registry an electrode in the path of said electrons, an with said apertures and means on the facing electron lens assembly positioned betweensaid surfaces of said plates extending toward each 50 cathode means and said electrode and through other for providing an aperture between said which the path of the beam of electrons lies, said cathode means and said focusing electrodes. lens assembly including a pair of plate members 4. An electron discharge device having cathode having. oppositely disposed apertures therein, means for supplying a beam ‘of electrons and an means for maintaining said plate members in electrode in the path of said electrons, and means spaced relationship and including a pair of elon positioned between said cathode means and said ‘gated members extending from one side there electrode and including an electron lens system ‘of, focusing electrodes mounted on the outside comprising a pair of oppositely disposed plate surfaces of said plate members and insulating like members having registering apertures and ly supported thereon in registry with said aper spaced apart and between which the beam path 60 tures and de?ecting electrodes mounted on said lies, focusing electrodes insulatingly supported elongated members ‘between said focusing elec on the outside of said plates in registry with trodes and the electrode in the path of said elec-» said apertures and means on ‘the facing sur trons. faces of said plates extending toward each other EDWARD W. HEROLD.