US3483349A - Process for assembling an electron tube electrode - Google Patents

Description

1.. R. WANNER 3,483,349

PROCESS FOR ASSEMBLING AN ELECTRON TUBE ELECTRODE Dec. 9, 1969 Original Filed July 11, 1966 INVENTOR.

ATTORNEY LOUIS R. WANNER BY d 7" United States Patent ()fiice 3,483,349 PROCESS FOR ASSEMBLING AN ELECTRON TUBE ELECTRODE Louis R. Wanner, Seneca Falls, N.Y., assignor to Sylvania Electric Products Inc., a corporation of Delaware Original application July 11, 1966, Ser. No. 564,205.

Divided and this application Apr. 8, 1968, Ser.

Int. Cl. B23k 9/02, 11/02, 11/04 US. Cl. 219107 3 Claims ABSTRACT OF THE DISCLOSURE CROSS REFERENCE This invention is a division of an application entitled: Electron Tube Electrode, filed July 11, 1966, US. Ser. No. 564,205, in the name of the applicant of the present application.

BACKGROUND OF THE INVENTION Conventional cathode ray tubes utilize at least one electron gun structure which usually comprises a plurality of longitudinally arrayed electrodes in spaced axial alignment. In certain types of electron guns, a two member electrode structure is utilized; as for example the doubleend anode commonly employed in the low focus voltage electron gun. A double-end structure of this type is usually comprised of two similarly formed cup-like elements, such as an inner and an outer member, each having an open end, an inwardly turned flange portion in the form of a partially closed opposite end with a terminally formed aperture therein, and a substantially cylidrical body or skirt portion integral to the flange portion. The two members differ diametrically in substantially the skirt and flange portions to facilitate the compatible telescoping of the skirt portion of the inner member Within the skirt portion of the outer member to thereby provide a doubleend electrode having a terminally formed aperture at either end. As these apertures aid in forming the focusing lenses of the gun, it is very important that they be in axial alignment with the other gun electrodes. Any displacement of the apertures or unintentional tilt of the electrodes causes the formation of electrostatic fields which are not axially symmetrical to the axis of the electron beam. Such aggravating fields distort the shape of the electron beam and result in degradation of picture quality.

The fabrication of the described substantially cylindrical inner and outer members is usually accomplished by a drawing operation wherein it is necessary to have a slight longitudinal diametrical divergence in the parts to facilitate withdrawal of the male die portion. Parts formed in this manner evidence a slightly larger diameter at the open end than at the inwardly turned flange portion of the aperture end. Thus, the achievement of accurate alignment through the telescopic assembly of such parts is a diflicult operation due to the presence of diametrical divergences and manufacturing tolerances.

A conventional bonding procedure for joining the telescoped members is one wherein transverse welding is 3,483,349 Patented Dec. 9, 1969 utilized diametrically across the assembly. The diametrical pressure necessary, in this welding procedure, to bond the assembled members aggravates the misalignment situation. If, on the other hand, the transverse Welding pressure is insufficient to effect electrical contact between the assembled member, inadequate jointure of the assembly results. Because of the normal tolerances of the telescoped members, the first weld tends to tilt the inner member in an off-axial direction and subsequent welds sequentially applied promote out-of-roundness of the assembled structure. Thus, misalignment of the two-member double-end electrode has been a troublesome problem in eletcron gun construction resulting in a considerable number of alignment rejects.

OBJECTS AND SUMMARY OF THE INVENTION It is an object of the invention to reduce the af0rementioned disadvantages and to improve the fabrication of telescoped two-member electrode assemblies.

Another object is to provide means for improved alignment and jointure that are integral to the parts assembled.

Further objects are to reduce the number of alignment and jointure rejects occurring from the critical construction of the two-member, double end electrode assembly.

The foregoing objects are achieved in one aspect of the invention by the provision of a double-end electrode structure formed of two compatibly formed cup-like members each having a leading edge, a skirt portion and an inwardly turned flange portion with a related aperture axially oriented therein. The leading edge and skirt portion of the cup-like inner member are telescoped within the skirt portion of the cup-like outer member. The telescoping movement therebetween is limited by abutment of the leading edge of the inner member with a plurality of spaced-apart like protnberances extending interiorly from the inwardly turned flange portion of the outer member whereat jointure is effected to provide desired alignment of the two members and the respective apertures therein.

For. a better understanding of the present invention, together with other and further objects, advantages, and capabilities thereof, reference is made to the following specification and appended claims in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a diagrammatic view showing an electron gun as utilized in a cathode ray tube;

FIGURE 2 is a sectional view showing one embodiment of the invention;

FIGURE 3 is a sectional view showing another embodiment of the invention; and

FIGURE 4 is a sectioned view showing means for assembling the two member electrode structure of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGURE 1 there is shown a typical electron gun 11 as utilized in a conventional cathode ray tube wherein a plurality of cooperating electrodes are spaced and electrically energized to form and control desired electron beam 15. Electron generators of this construction may be incorporated individually or plurally within many types of cathode ray tubes depending upon the nature of the display function desired.

In greater detail, the electron gun 11 is shown as comprising an electron beam source 17 having electron emissive material 19 deposited thereon in a manner that the electrons emitted therefrom will form electron beam 15. Spaced from the electron source 17 and positioned in sequential concentrical array along the path of electron travel are a number of cooperating electrodes such as: a

first apertured grid 21, a second apertured grid 23, an electron accelerating anode 25 having a first lens cup 27 with an axial aperture 29 therein and a second lens cup 31 with an axial aperture 33 therein, an electrostatic focusing electrode 35, and a fiinal anode structure 37 having a lens cup 39 with an aperture 40 therein.

Accurate coaxial alignment of the respective apertures of the several electron gun electrodes is essential for desired operational efiiciency. The electron beam 15, which is directed and made convergent to provide a spot of minimum diameter on a cathodoluminescent screen, not shown, is focused by the electron lens formed by the focusing assembly 47 which comprises the final anode lens cup 39 and the second anode lens cup 31 spacedly encompassed by the focusing electrode 35. Partial prefocusing and beam acceleration is furnished by the anode first lens cup 27 in cooperation with apertural configurations and spacings of the preceding first and second grids 21 and 23 respectively.

With reference to FIGURE 2, the accelerating anode 25, in this instance, is a two-member double-end apertured electrode structure wherein the first or outer member 26, containing the first lens cup 27, must be properly mated with the second or inner member 30, containing second lens cup 31, to produce the desired coaxial alignment of the respective apertures 29 and 33 therein.

It will be noted that the outer member 26 has a skirt portion 45 having a leading edge 47 and an oppositely disposed integral inwardly turned flanged portion 49 merging to a diametrically reduced first lens cup portion 27 having the related aperture 29 therein. Extending interiorly from the flanged portion are a plurality of at least three spaced-apart like protuberances 51. Extending exteriorly from the skirt portion are a plurality of electrode support studs 52, of which two are shown. These are bonded to the skirt portion, such as by Welding, and are utilized to support the completed anode in the electron gun 11 by means not shown.

Telescoped Within the aforementioned outer member 26 is a compatibly formed inner member 30 having a skirt portion 53 with a leading edge 55 therearound and an oppositely disposed integral inwardly turned flange portion 57 having a diametrically reduced second lens cup portion 31 with the related aperture 33 therein. The telescoping movement of the skirt portion 53 of the inner member 30 within the skirt portion 45 of the outer member 26 is limited by portions of the leading edge 55 of the inner member abutting the interiorly extending protuberances 51 of the outer member. It has been found that the discrete plural-point contact of the inner member with the several interior protuberances of the outer member markedly improves the desired axial alignment of the two members comprising the dual apertured anode structure 25. In addition, jointure between the two telescoped members at the abutment areas is achieved in an improved manner to promote and preserve the desired alignment provided by the aforedescribed abutment.

In referring to FIGURE 4, there is shown the accelerating anode assembly 25 whereof the inner member 30 is compatibly telescoped within the outer member 26 from which outwardly extends a plurality of support studs 52. With the leading edge 55 of the inner member abutting the interior protuberances 51 of the outer member, the anode assembly is suitably positioned in a bonding device 61. In this instance, bonding is effected by welding, and the device utilized comprises a first 'Welding electrode structure 63 of a suitable electrically conductive material, such as copper or an alloy thereof, having a welding surface 65 with a recess 67 therein formed to diametrically accommodate the first lens cup portion 27 of the outer member 26 by a sliding fit therein. In this manner the outer member is suitably oriented in the first welding electrode with the flange portion 49 being in contact with the electrode welding surface 65.

The bonding device has an insulative shell-like member 69, as of hard nylon, conjunctively associated with the first electrode structure 63, with an upstanding wall 70 formed to define a cavity 71 which is dimensioned to spacedly accommodate the anode assembly 25 and its outwardly extending support studs 52.

A second electrode structure 75 of a suitable electrically conductive material, such as copper or an alloy thereof, is dimensioned to slidably fit within the upstanding insulative wall 70. This second electrode has a welding surface 77 with a recess 79 formed therein to diametrically accommodate the second lens cup portion 31 of the inner member 30 by a sliding fit therein. Thus, the inner mem her is oriented in the second welding electrode with the flange portion 57 being in contact with the welding surface 77. The second electrode structure also has cut-out or recess provisions to spacedly accommodate the support studs on the outer member of the anode assembly.

With the telescoped anode assembly so positioned in the welding device 61, axial pressure is applied to the first and second electrode structures in the directions as indicated by arrows A and B in FIGURE 4, by means not shown. It will be noted that the axial pressure is transferred to the flanged portions of the respective telescoped members. This axial pressure effects positive abutment contact between portions of the leading edge of the inner member with the inwardly extending protuberances of the outer member.

When suflicient pressure is applied in an axial manner to make the desired alignment and abutment contact between the two members, a welding potential is supplied to the respective first and second welding electrode structure 63 and 75 by a connected welding power supply 81 through the activation of electrical switching means 83. Thus, multi-point juncture is consummated, and the desired axial alignment of the apertures in the telescoped two-member double-end electrode assembly is achieved in an improved fabrication manner.

Another embodiment of the invention utilizing pressured abutment is shown in FIGURE 3 wherein the outer member 26' has an inwardly turned flange portion 49' with no protuberances extending interiorly therefrom; instead, the inner portion 30' has a plurality of spacedapart like projections extending linearly from the leading edge 55' to be in discrete abutment and jointure with portions of the inwardly turned flange portion 49 of the louter member. Such projections are at least three in num- Use of the alignment and jointure means of this invention, along with the method of assembling the two member electrode structure, results in a vastly improved double-end anode that has desired apertural alignment, and one that is not diametrically deformed during fabrication. Positive alignment and multiple-point bonding effect an electron gun electrode structure that is definitely superior to prior art telescoped electrodes that have been transversely welded diametrically across the assembly.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

I claim:

1. A process for assembling a two-member electron tube electrode structure having apertures at both ends thereof wherein an apertured inner cup-like member having a skirt-portion, an inwardly turned flange portion, and a leading edge, has the skirt-portion telescoped within a compatibly formed apertured outer cup-like member also having a skirt portion and an inwardly turned flange portion, said process comprising the steps of:

positioning said inner and outer members with said skirts thereof in telescoped relationship with the telescoping movement therebetween being limited by at least three spaced apart portions of said leading edge 5 6 of said inner member'abutting on at least three 3. The assembling process according to claim 1 Wherespaced apart portions of the interior surface of said in said jointure is consummated at the respective forward inwardly turned flanged portion of said outer memedges of at least three spaced-apart like projections extendber; ing linearlyv from the leading edge of said inner member applying axial pressure against substantially only the skirt portion to make discrete seating contact on portions exterior surface of each of said inwardly turned of the interior surface of said inwardly turned flange porflange portion of said telescoped members to effect tion of said outer member. positive seated abutment on said discrete areas of contact therebetween; and References Cited making electrical contact with the exterionsurface of 10 UNITED STATES PATENTS each of sald lnwardly turned flange portion of said pressured telescoped members to complete a welding cf g circuit to consummate jointure of said members at 04540 11/1908 L chona "T substantially said discrete abutment contact areas to 3 2 7/1909 is gi 2 provide correct alignment of said electrode members 15 3 1 5/1967 Burdick et a1. 31382 and said apertures therein.

2. The assembling process according to claim 1 Wherein said jointure is consummated at points Where the lead- JOSEPH TRUHE Pnmary Exammer ing edge of the skirt portion of said inner member makes L. H. BENDER, Assistant Examiner discrete seating contact on at least three spaced-apart like 20 protuberances extending interiorly from said flange portion of said outer member. 21993

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