US3197666A - Electron tube having a novel electrode support arrangement - Google Patents

Description

J ly 1965 J. w. GAYLORD ETAL 3,197,655

ELECTRON TUBE HAVING A NOVEL ELECTRODE SUPPORT ARRANGEMENT Filed Oct. 9. 1961 m0 4 mM M. mm M J w 5 1 MM 4 JJ W B K Z 5 ml M conductors.

United States Patent 3,197,666 ELEQTRON TUBE HAVING A NOVEL ELEC- TRODE SUPPORT A'GEMENT John Wallen Gaylord and John B. Pyle, both of Lancaster,

Pa, assignors to Radio Corporation of America, a corporation of Delaware Filed Oct. 9, 1961, Ser. No. 143,846 Claims. (Cl. 313-255) Our invention relates to electron tube-s and particularly toa novel method of manufacture thereof.

One tube type has a structure comprising an envelope formed by a. stacked array of alternately disposed insulating rings usually made of ceramic, and annular lead-in Such envelope structure is characterized by several problems.

One problem arises as a consequence of the relatively large number of ceramic-to-metal seals required in tube structures of this type. ,In a tetrode, for example, at least three insulating rings are usually required, for insulating four flange-like lead-in conductors from each other. This involves six ceramic-to-metal seals. Such large number of seals increases the hazard of envelope leaks.

Other problems involve the cost of tube manufacture by virtue of complicated jigging techniques usually required, and the relatively large amount of material necessary to provide the large number of insulating rings and annular lead-in conductors.

Accordingly it is an object of the invention to provide an improved electron tube.

Another object is to provide an improved method of making an electron tube.

A further object is to provide an improved sub-assembly of electrodes and an electrode support, for ec onomical manufacture and to provide an improved structure, of an electron tube.

In one example of the invention, a sub-assembly for a tetrode type of electron tube includes a screen grid having an annular lead-in conductor. A tubular control grid and a cathode support are insulatingly fixed to the screen grid lead-in conductor by means avoiding the need for annular lead-in conductors for the control grid and cathode support. Leads for the control grid and cathode support are so oriented that not only is it feasible to connect wire or pin-type lead-in conductors to these leads, but a portion of the annular lead-in conductor for the screen grid within the tube envelope is exposed for also aflixing thereto wire lead-in conductors.

In a tube structure incorporating the aforementioned sub-assembly, the wire lead-in conductors are satisfactorily insulated from each other by passing through an insulating header in spaced relation. Consequently, the header serves the insulating function of several of the insulating rings heretofore required.

While some support of the screen grid control grid and cathode support is provided by the wire lead-in conductors fixed thereto as aforementioned, the major support is realized by the annular lead-in conductor of the screen grid, which is sealed through the tube envelope.

In the tube structure described, only one insulating ring is required. This ring is disposed between an anode leadin flange and the annular flange-like lead-in conductor of the screen grid. Effective insulation among the screen grid, control grid and cathode support is afforded by the insulating header aforementioned.

A feature of the invention involves an annular lead-in conductor for the screen grid having a structure affording access to the control-grid and cathode-"support leads, thereby permitting a convenient fixing of the leads to their respective wire lead-in conductors.

The novel sub-assembly referred to contributes to fa- 3,197,666 Patented July 27, 19x35 ice cility in manufacture, in that the major assembling operation may be performed by self-jigging techniques.

Further objects and advantages will become apparent from the following detailed consideration of an embodiment of the invention.

In the accompanying drawings,

FIG. 1 shows an elevation partlyin section of an electron tube incorporating the invention;

FIG. 2 is sectional view, taken along the line 2-2 of FIG. '1 and shows the electrode complement of the tube of FIG. 1;

FIG. 3 is an exploded view, partly in section, of the several sub-assemblies constituting the tube of FIG. 1;

FIG. 4 is a bottom view of the screen grid, control grid and cathode support sub-assembly shown in FIG. 3;

FIG. 5 is a top view of the sub-assembly including the annular lead-in conduct-or for the screen grid,.shown in FIG. 3;

FIG. 6 is a sectional view taken along the line 66 of FIG. 3; I 7

FIG. 7 is a bottom View of the electron tube shown in FIG. 1, and depicts the array of wire or pin lead-inconductors extending through the header of the tube;

FIG. 8 illustrate the-relatively simple jigging required in assembling the parts constituting the screen grid, control grid and cathode support sub-assembly shownin FIG. 3, and shows these parts assembled for brazing; and

FIG. 9 shows the completed screen grid, control grid and cathode support sub-assembly, assembled with a tubular cathode on suitable jigs in a bell jar for brazing the cathode to the sub-assembly referred to.

An example of an electron tube in which the invention may be used is shown in FIG. 1. The tube includes an exposed tubular anode 10, closed at one end by a pinchedoff exhaust tubulation 12, and fixed at the other end to an annular flange 14 which may serve as a lead-in conductor.

Coaxially within the anode 10, is a complement of electrodes, as shown more clearly in FIG. 2, comprising (in order from outside in) a screen grid 16, a control grid 18, a tubular cathode 20 and a coiled heater 22 supported on a conducting rod 24. The screen grid 16 and the control grid 20 may comprise tubular structure perforated by a process of electrical discharge machining to provide, respectively, relatively Wide stiffening ribs '26, and 28 in radial register, and to form a plurality of wires 2), 31 between the ribs, also in accurate radial register. The cathode 2i includesa metal sleeve, made of nickel for example, and having thereon the usual electron emitting oxides of barium, strontium and calcium; The heater 22 may comprise a tungsten wire having thereon an insulating coating of aluminum oxide, for example. As shown in FIG. 3, one end of the heater is-fixed to the top of the conducting rod 24, the lower end portion of which is fixed at 30 to wire conductor 34 which seal-ingly passes through a header 32 of insulating material, such as aluminum oxide. The other end of the heater is connected to a wire conductor or prong 36 also sealingly passing through the header 32.

' A feature of the invention is characterized by the fact that only one insulating ring 38 (FIG. 1) is utilized in the envelope structure of the tube; Consequently, the

likelihood of air leaks through the tube envelope is considerably reduced. The ring 38, as shown in FIG. 3, is incorporated in the-anode sub-assembly 40. Also included'in this sub-assembly is a metal sealing ring 42.

A further feature of theinvention concerns the header sub-assembly 44. This sub-assembly .as shown in FIG. 3 includes the header 32 and a metal sealing ring 46. The diameters of the sealing rings 42 and 46 aresuch that sealing ring 42 fits snugly within sealing ring 46, thus rendering self-jigging of these pants feasible.

The novel screen-grid, control-grid and cathode-supanemone port sub-assembly 48 is illustrated in FIG. 3. This subassembly requires only one annular lead-in conductor 50, which in the assembled tube of FIG. 1, is fixed to metal ring 46 associated with the header sub-assembly 44. The annular lead-in conductor 50 is suitably fixed to or may be integral with one end of the screen grid 16 and defines a partly closed region. The control grid 18 has one end terminating in said region and provided with a plurality of radially extending tabs 52, 54, 56, 58, 60 shown in FIGS. 3 and 4. A ring-like cathode support 62 is provided with a cylindrical flange 64 and a plurality of tabs 66, 67, 68,70 and 72. Diametrically opposed tabs 52, 54 (FIG. *3) of the control grid are coextensive respective'ly with diametrically opposed tabs 66, 63 of the cathode support. These tabs serve to fix the control grid and the cathode support to the screen grid flange 58 in a manner to be described.

Between radially extending control grid tab 52 and the radially extending portion of the screen grid flange 50, are disposed two pins 74, 76 (only one of which, 74, is visible in FIG. 3 both being visible in FIG. 6) made of an insulating material such as aluminum oxide, and suitably metalized at their ends to facilitate brazing of the ends to the inner wall of flange 350 and an upper surface (as oriented in FIG. 3 or 6) of tab 52. Second group of two pins 78, 81 (FIG. 6, only pin 78 being visible in FIG. 3) also made of an insulating material such as aluminum oxide. These two pins, suitably metalized at their ends, are brazed to facing surfaces of tabs 52, 66. The tabs 52, 66 are appreciably wider than the other tabs as shown in FIG. 4, .and coextensive in this view, to contribute ruggedness to the support of the control grid 18, (FIG. 3) and cathode support 62, by the screen grid flange 50. Tab 54 on the control grid and tab 68 on the cathode support also serve to fix the control grid and cathode support to the screen grid flange 5,0. These tabs, however, are appreciably narrower than tabs 52, 66, and are coextensive in the view of FIG. 4 and 'insulatingly fixed to the screen grid flange 50, by an additional set of two insulating pins 79, 80, ('FIG. 3) also made of aluminum oxide, for example. It has been found by applicants that this combination of tabs and pins affords a relatively rugged support of the control grid 18 and cathode support 62 on the screen grid flange 50.

The tabs extending from the control grid and cathode support, other than the four tabs 52, 54, 6 6, 68 refer-red I to for mounting purposes, are utilized to engage wire or rod-like lead-in conductors extending through the header 32. The tabs on the control grid serving this function, are tabs 56, 58, and 60, while those on the cathode support are tabs 67, 70 and 72, as shown in FIG. 4,

It will be noted from FIGS. 3 and 4 that the radially extending portion of flange 50, and the tabs associated with the control grid 18 and the cathode support 62 are spaced axially of the sub-assembly 48. This requires wire lead-in conductors of different length in order to engage the differently spaced flange and tabs. To this end one group of three angularly spaced wire lead-ins, one of which is shown at 84 in FIG. 3 is adapted to engage the tabs 67, 70 and 72 serving the cathode support, and another group of three angularly spaced wire lead-in conductors, one of which is shown at 86, in FIG. 3, is adapted to engage the tabs 56, 5,8, 60, extending from the control grid .18. Another group of three wire lead-ins one of which is shown at 87 is adapted to be fixed to the inner surface of the radially extending portion or flange 50. I

Only one lead-in conductor of each group of conductors serving the several tube elements is shown in FIG. 3 in the interests of simplicity. The full complement of lead-ins is shown in FIG. 7. As shown in these figures, lead-in conductors 84, 84a, 8411 have free ends terminating in a plane relatively close to the inner surface of header 32. The free ends of these conductors engage tabs 67, 70 and 72 of the cathode support 62, which is the lowermost of the elements to be engaged by lead-in conductors as shown in FIG. 3. Lead-in conductors 86, 86a, 86b have free ends terminating in a plane farther spaced from the header 32, than the plane of conductors 84, 84a, 34b and are adapted to engage tabs 56, 58 and 60 of the control grid .18. Conductors 87, 87a, 87b have free ends terminating in a plane more remote from that of conductors .86, 86a, 86b, and are adapted to engage the inner surface of the radially extending portion of annular lead-in conductor 50 As shown in FIG. 7, each group of lead-in conductors, with the exception of header conductors 34, 36, has the conductors therein spaced substantially equidistantly in a circle concentric with the header 32.. This provides a relatively rugged tripod type of support for the cathode 20 control grid .18 and the screen grid 16. This support for the screen grid supplements the relatively rugged support thereof provided by the annular lead-in conductor 50.

The aforementioned engagement between the groups of lead-in conductors represented by conductors 84, 86 and 87, and the tabs extending from the control grid and cathode support and inner surface of flange 50, occurs when the sub-assembly '48, after a fixing of cathode 20 thereto in a manner to be described, is positioned over the header sub-assembly 4-4 with the flange 5t) telescoped over flange 88 of the sealing ring 46. The lead-in conductors or wires 84, 86 and 87 are sufficiently long to contact their respect-ive'tabs and the flange 50, when the flange 50 is telescopingly seated on the flange 88, for self-jigging purposes.

If desired, the flange 88 may have a diameter to permit it to be 'telescoped ove-r annular lead-in conductor 50. In this example, a desired position of the conductor 50 with respect to the flange 88 will occur when the free ends of the wire lead-in conductors abutt-ingly engage their respective electrode elements, as aforementioned. Self-jigging of sub-assemblies 48 and 44, is thus feasible in either of the two ways discussed and contributes to facility in assembling the electron tube shown in FIG. 1.

To assure the desired contact between the lead- inconductors 84, 86 and the .tabs on the control grid and cathode support, the sub-assembly 48 is axially rotated with respect to sub-assembly 44 after seating on the flange 88 and the positions of the tabs and the upper ends of the lead-in wires 84, 86 are observed through openings, shown in FIG. .5, in the radially extending portion of screen grid flange 50. Six holes or openings 90, 92, 94, 96, 98, 1% are provided in the radially extending portion referred to. The holes are spaced from each other in an array similar to the array of the lead-in tabs on the control grid and cathode support. It will be noted that the lead-in conductors 84, 86 are also spaced in this array. It can readily be determined, by looking through the holes referred to, when a desired angular orientation of the sub-assembly 48 with respect to subassembly 44, is secured, in which the upper ends of the wire lead ius referred to engage appropriate tabs.

After such orientation and contact, relatively thin welding electrodes are extended into the holes 90 to 100, and engage and heat the tabs to a sufliciently high temperature, to produce a weld between the tabs and upper ends of lead-in wires 84, 36. A welding electrode contacting the outer surface of the radially extending portion of flange 50, serves to weld the flange to the upper ends of the three lead-in wires represented by wire 87.

It is to be noted that prior to the step of welding the wires of groups 84, 86, 87 to their respective lead-in tabs of the control grid, cathode support and flange 50, the subassembly {38 and cathode 20 (FIG. 3) have been assembled and fixed. The assembling operation to provide sub-assembly 48 involves first mounting the screen grid, control grid and cathode support on a mandrel 102, in a position inverted from that shown in FIG. 8. In such inverted position of the mandrel 102, it will be convenient to mount thereon first the cathode support 62 shown in FIG. 3. Thereafter the three insulating pins 78, 81, 80 (FIGS. 3 and 6) are placed on the tabs 66, 68. The control grid is positioned so that its tabs 52, 54 engage the previously positioned insulating pins 78, 8G, 81. Thereafter the three insulating pins 74, 76, 79 are placed on the control grid tabs 52,54 The flange 50 of the screen grid 16 is then telescoped over the elements so rfar mounted while angularly orienting the same so that the lead-in tabs 56, 58, 60, 67, 78 and 72 are visibly oriented through holes 98 to over the ends of the wire condoctors as shown in FIG. 5. It should be noted that when mounting the cathode support 62 and the control grid 18 on the mandrel 102, these parts are angularly oriented so that tabs 52, 54 of the control grid are in coextensive register with the tabs 66, 68 "on the cathode support 62. When this register occurs, the lead-in tabs 56, 58, 68, 67, 78 and 72 automatically assume the orientation depicted in FIG. 4.

It will be seen in FIG. 8, that the control grid 18 and screen grid 16 have openings 184, 106 at the ends thereof remote from flange 58 and tabs 52, 54. The mandrel 102 includes a pin-like portion 107 adapted to enter the afore mentioned openings, snugly. The mandrel also includes two progressively wider portions 108, 110, adapted to snugly engage the inner surface of control grid 18 and the cylindrical portion of flange 50, respectively. The portion 188 is also adapted to engage snugly the inner wall of cathode support 62.

The mandrel 102 may be positioned in an oven 112 either in the position shown. in FIG. 8 or in the inverted position assumed during the mounting of the parts thereon. The oven contains a reducing gas such as hydrogen and is heated to a temperature of about 800 C. for brazing the ends of the insulating pins to their engaged tabs and to the inner surface of flange 58. To permit such brazing the ends of the pins are coated with a metal such as molybdenum.

After the sub-assembly 48 has been completed in the manner described and before this sub-assembly ,is mounted on the header sub-assembly 44, the cathode 28, is mounted on and fixed to the cathode support 62. The cathode is provided with a structure to facilitate its mounting on support 62. Thus, one end portion 114 of the cathode is appreciably of larger diameter than the other portions 116, 118 thereof. The outer diameter of portion 114 is such as to afford a snug fit into the cylindrical portion 64 of the cathode support. The

diameters of the cylindrical portion 64 of the cathode support 62 and the control grid 18 are substantially the same so that in addition to facilitating jigging, a convenient reference means comprising the difference between the outer diameters of portions 114 and 118 of the cathode is provided to determine the spacing between the cathode and the control grid. The wall of portion 116 of the cathode is relatively thin for service as a heat dam.

In assembling the cathode 20 in the subassembly 48, two jigs 122, 124 (FIG. 9) are employed. Jig 122 comprises a cylindrical portion adapted to enter the cathode 20 snugly and to abut against the lower end wall of the cathode as viewed in FIG. 9. Jig 124 includes a relatively thick portion 126 adapted to enter holes 184, 186, in the end walls of control grid 18 and screen grid 16, respectively, of sub-assembly 48. Jig 124 also includes a relatively thin portion 128 adapted to enter a relattively small hole 130 in the end wall of the cathode 28. When the jig portion 18 is extended into the hole 130 and the cathode extended through the cathode support 62 so that the support engages the relatively thick cathode portion 114, the cathode and sub-assembly 48 are in correct relative positions for fixing the cathode to its support 62.

Such fixing may be effected by disposing the cathode 20 and sub-assembly 48 assembled as aforementioned, in a bell jar 132 containing a reducing gas such as hydrogen. A coil 134 is then positioned around the flange 64 of the cathode support and connected by leads 136, 138, to a suitable source of RF. power for heating the support flange 64 and the relatively thick portion 114 of the cathode to a brazing temperature. In view of the relatively large magnitude of power required to energize the coil 134, the coil and its leads 136, 138 may be tubular to accommodate a cooling fluid circulated therethrough.

After the cathode 28 has been added to sub-assembly 48 in the manner indicated, sub-assembly 48 may be mounted on the header sub-assembly 44 with the cylindrical portion of the screen grid flange 58 telescoped lover or within the cylindrical portion 88 of flange 46, and welded thereto. It is to be noted that when the flange 58 is seated in telescoped relation over flange 88, or when the flange 50 is disposed within flange 88 and the lead-in conductors 84, 86, 87 serve as top means, the elements of subassembly 48 are in accurate coaxial relation with respect to the elements of the header sub-assembly 44, and appropriately axially spaced.

Thereafter, the anode sub-assembly 48 in mounted on the header sub-assembly 44 with the sealing flange 42 on the former snugly received within the sealing flange 46 of the header. When seated relation of flange 42 in flange 46 occurs, the anode sub-assembly is coaxial with the combined assemblies 48, 44, and the assemblies are desirably spaced axially.

The extensive self-jigging that is thus feasible contributes to economy in manufacture as well as to an improved tube structure.

It will be noted that in the complete tube, cylindrical flanges 42 and 46 constitute an annular lead-in conductor serving the screen grid 16. While the screen grid is also served by wire lead-ins, as explained in the foregoing, the added provision of an annular lead-in conductor is of advantage not only in affording self-jigging and support for the control grid and cathode, but in widening the utility of the tube. Thus its output electrodes, (the anode and screen grid) may be associated at will with either lumped or tank cicruits. The flange lead-in conductor for the screen grid, moreover, serves advantageously as a heat dissipating means, thereby contributing to a reduction in the operating temperature of the screen grid and to improved tube operation.

A feature of particular significance in the manufacture of the tube involves the order in which the ribs 26, 28 and the Wires therebetween in the control grid 18 and screen grid 16, are formed in relation to assembling of the parts constituting sub-assembly 48. In this connection, it should be noted that the ribs and grid Wires in the'two grids should be accurately aligned radially of the grid structures. It is diflicult to secure such alignment during the step of assembling the parts of this sub-assembly. Therefore, in accordance with the invention, the parts forming sub-assembly 48 are first assembled and the control grid 18 and the cathode support 62 are angularly oriented to dispose the tabs 56, 58, 68, 66, 67, 68, 70, 72, in the pattern shown in FIG. 4. After such assembling step and a fixing of the parts in their assembled positions,

the two grids are subjected to an operation of forming the ribs 26, 28 and the grid wires therebetween. This operation may involve electrical discharge machining utilizing a breach electrode of a shape to form accurately radially aligned axial slots in the'two grids between desired accurately radially aligned bars and wires as described in Patent 2,980,984. It is thus apparent that the step of angularly orienting the control grid and the screen grid to form the tab pattern shown in FIG. 4 is not critical and is satisfactory if the mounting tabs 52, 54,-and 66, 68 are approximately in coextensive relation to accommodate the insulating pins aforementioned therehetween. The angular spacing between the other tabs employed as con- 3,197,eee

doctors, is sufficiently large to permit of some variation therein without harmful results.

It is apparent from the foregoing that we have provided an improved electron tube structure and a novel and advantageous method of making the same.

We claim:

1. An electron tube having an envelope, a first elongated electrode within said envelope, an annular conductive structure connected to one end of said electrode and sealed through the wall of said envelope, said structure defining a cup-shaped portion within said envelope, and a second electrode insulatingly fixed to spaced portions only, of said annular structure and within said cup-shaped portion.

2. An electron tube having an envelope an elongated screen grid within said envelope, an annular flange extending through the wall of said envelope and conductive- 1y engaging one end of said screen grid, and a control grid in coaxial relation with respect to said screen grid, said control grid being insulatingly fixed to one face only, of said flange and extending beyond the opposite face of the flange.

3. An electron tube having an envelope, an annular metallic member extending through the wall of said envelope and including a portion extending inwardly of said envelope, and an electrode sub-assembly within said envelope, said electrode sub-assembly comprising a plurality of electrodes, and a metallic support for one of said electrodes. fixed to said inwardly extending portion, the other electrodes being insulatingly supported on said support.

4. An electron tube having an envelope, a conductive electrode support extending through the Wall of said envelope and having a fiat surface portion, and a plurality of electrodes supported on said flat surface portion only, in insula'tedrelation with respect to each other and said surface portion.

5. An electron tube having an envelope, a conductive annular electrode support extending through the Wall of said envelope, said support including a cylindrical flange entirely within said envelope and defining a partly closed space, a first electrode conductively mounted on said support at a region thereof outside of said space, and a second electrode insulatingly mounted on said support and within said space.

6. An electron tube comprising an envelope, a plurality of electrodes within said envelope, an insulating header, a plurality of lead-in conductors extending through said header and electrically connected to said electrodes, and an annular metallic support conductively engaging one of said electrodes and extending through a wallof said envelope, the other electrodes being insulatingly en gaging on said support within said envelope.

7. An electron tube having an envelope, an annular conductive support structure extending through a Wall .of said envelope, a first electrode conductively fixed to said structure, a second electrode having a first group of radially extending tabs insulatingly fixed to said structure and a second group of radially extending tabs angularly spaced from said first group, and a plurality of wirelike conductors connected -to said tabs of said second group.

8. An electrode mount comprising a first tubular electrode, an electrode support having a tubular portion coaxial with said first electrode, said first electrode and said tubular portion having substantially the same inner diameter, a second tubular electrode having an end portion thereof fixed to the inner surface of said tubular portion, and another portion extending within said first electrode, the wall of said second electrode at said end portion being thicker than the wall of said another portion to provide a desired spacing between said another portion and said first electrode, a common conducting support for said first electrode and said electrode support,

and means electrically insulating said second electrode from said common support.

9. An electron tube comprising an envelope, a header forming a wall portion of said envelope, a metallic flange coaxial with said header and sealed through another wall portion of said envelope, an electrode supported on said flange, said flange having a radially extending portion normal to the axes of said header and flange, and a lead-in conductor extending through said header along an axis normal to and in register with said radially extending portion, whereby said conductor is adapted to be fixed to said radially extending portion.

10. An electron tube comprising an envelope, a metal support within said envelope and extending through a wall thereof, a first tubular electrode within said envelope and conductively supported on said metal support, a second tubular electrode within said first electrode and having an end portion adjacent to but spaced from said metal support in a direction away from said first electrode, a third tubular electrode within said second electrode and having an end portion adjacent to but spaced from said first named end portion in said direction, said end portions each having a plurality of conductive tabs extending radially therefrom, two of said tabs on each of said second and third electrodes being in facing relation, the others of said tabs being oifset angularly, and a plurality of leadin conductors extending in a direction normal to said tabs and fixed thereto.

11. An electron tube having an envelope, a header in the wall of said envelope, an annular metallic structure in coaxial relation to said header and extending through the wall of said envelope, a first electrode conductively supported on said annular structure, a second electrode extending through said annular structure and having an end portion adjacent thereto, a plurality of angularly spaced tabs extending radially from said end portion, insulating =means fixing two of said tabs to said structure, others of said tabs being free from contact with said structure, a first group of wire-like lead-in conductors extending through said header and fixed to said others of said tabs, and a second group of wire-like lead-in conductors extending through said header and between said others of said tabs into contact with said annular structure.

12. An electron tube comprising an envelope, an annular metallic support structure sealed through an annular portion of said envelope, a first tubular electrode fixed at one end thereof to said structure, a second tubular electrode extending into said first electrode and having an end portion extending beyond said first electrode and adjacent to said structure, two tabs extending in a radial array from said end portion and substantially oppositely disposed in said array, one of said tabs having an appreciably greater arcuate extent in said array than the other tab, an insulating pin sealed to one face of said other tab and to said structure, and two spaced insulating pins sealed to one face of said one'of said tabs and to said structure, whereby said second electrode is ruggedly supported on said structure.

13. An electron tube having an elongated envelope closed at one end by an anode and at the other by an insulating header, said envelope including an insulating sleeve intermediate said anode and header, a first annular metal flange connected to said anode and sealed to one end of said sleeve, a second annular metal flange sealed to said header and to the other end of said sleeve, an electrode within said envelope mounted in conductive relation on said second metal flange, a plurality of electrodes mounted in insulating relation on said second metal flange,

and a plurality of lead-in conductors extending through said header and in contact relation with said plurality of electrodes.

14. An electron tube having an envelope comprising an insulating sleeve, a tubular anode structure supported on one end of said sleeve, and an electrode mount supported 9 on the other end of said sleeve, said mount including a metal flange and an insulating header, said metal flange being sealed between said other end of said sleeve and said header, said metal flange including a portion extending within said envelope, a plurality of electrodes insulatingly mounted on said portion, and a plurality of lead-in conductors extending through said header and electrically connected to said electrodes.

15. An electron tube comprising an envelope, an electrode assembly within said envelope, said assembly including a plurality of electrodes and comprising an annular conductor extending through the wall of said envelope and conductively supporting one of said electrodes, said conductor having a planar surface, and

means within said envelope insulatingly supporting the others of said electrodes on said planar surface.

Reierences Cited by the Examiner UNITED STATES PATENTS 2,428,661 10/47 Fitzmorris 313-265 X 2,469,331 5/49 Eitel etral 313-247 X 2,527,127 10/50 Gormley et a1 313-265 X 2,808,528 10/57 Martin 3133 17 X 2,916,649 12/59 Levin 3l3-257 X 2,935,783 5/60 McCullough et al 2925.16 2,996,637 8/61 Garner et a1. 313--265 3,068,548 12/62 Hergenrother et a1. 2925.16

GEORGE N. WESTBY, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 3,197,666 July 27, 1965 John Wallen Gaylord et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 3, line 25, for "Second" read A second column 5, lines 68 and 69, for "relattively" read relatively line 70, for "18" read 128 column 6, line 24, for

"in" read is column 7, line 53, strike out "on".

Signed and sealed this 19th day of April 1966.

TEAL) ttest:

RNEST W. SWIDER nesting Officer Commissioner of Patents EDWARD J. BRENNER 7

Claims (1)

1. AN ELECTRON TUBE HAVING AN ENVELOPE, A FIRST ELONGATED ELECTRODE WITHIN SAID ENVELOPE, AN ANNULAR CONDUCTIVE STRUCTURE CONNECTED TO ONE END OF SAID ELECTRODE AND SEALED THROUGH THE WALL OF SAID ENVELOPE, SAID STRUCTURE DEFINING A CUP-SHAPED PORTION WITHIN SAID ENVELOPE, AND A SECOND ELECTRODE INSULATINGLY FIXED TO SPACED PORTIONS ONLY, OF SAID ANNULAR STRUCTURE AND WITHIN SAID CUP-SHAPED PORTION.

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