US3725712A

US3725712A - Triple electron gun assembly having units attached by glass beads to protrusion from convergence electrode

Info

Publication number: US3725712A
Application number: US00184776A
Authority: US
Inventors: S Sawagata
Original assignee: Tokyo Shibaura Electric Co Ltd
Current assignee: Toshiba Corp
Priority date: 1970-10-20
Filing date: 1971-09-29
Publication date: 1973-04-03
Anticipated expiration: 1990-04-03
Also published as: JPS4922845Y1

Abstract

A triple electron gun assembly comprising three stacks of electrodes so arranged as to have their axes slightly inclined for convergence and a cup-shaped convergence electrode secured to the forward ends of the three electron gun units, said cup-shaped convergence electrode being provided with a protrusion having cylindrical walls corresponding in size and shape to the forward ends of the three electron gun units.

Description

O Umted States Patent 1 1 Sawagata [4 1 Apr. 3, 1973 [54] TRIPLE ELECTRON GUN ASSEMBLY [56] References Cited HAVING UNITS ATTACHED BY GLASS BEADS TO PROTRUSION FROM UNITED STATES PATENTS v CONVERGENCE ELECTRODE 3,250,935 5/1966 Johnson ..313/69 c x e 3 603 829 9/1971 Tsuneta et al. [7 5] lnventor. Shmlchl Sawagata, Nerlma-ku,

Tokyo Japan 3,643,121 2/1972 Sawagata et a1. ..3l3/70 C [73] Assignee: Tokyo Shibaura Electric Co., Ltd., primary Examine,- Robert Sega] Kawasakishi1 Japan Attorney-Flynn & Frishauf [22] Filed: Sept. 29, 1971 i R C 57 ABST A T [21] Appl. No.: 184,776 l A triple electron gun assembly comprising three stacks of electrodes so arranged as to have their axes slightly [30] Foreign Apphcamm Pnonty Data inclined for convergence and a cup-shaped conver- Oct. 20, 1970 Japan ..45/l03549 gence electrode secured to the forward ends of the three electron gun units, said cup-shaped convergence U-S- CL C, electrode being provided a protrusion having 3.13/262 cylindrical walls corresponding in size and shape to [51] Int. Cl. ..H0l 29/02, H01 29/50 the f d ends f the three electron gun units [58] Field 0i Search ..3l3/70 C, 69 C, 92 B 5 Claims, 4 Drawing Figures TRIPLE ELECTRON GUN ASSEMBLY HAVING UNITS ATTACHED BY GLASS BEADS TO PROTRUSION FROM CONVERGENCE ELECTRODE BACKGROUND OF THE INVENTION This invention relates to a triple gun assembly. With the prior art triple electron gun assembly, the convergence electrode is formed into a cup-shape whose bottom is provided with locating strips and three apertures whose centers are positioned at the apices of an equilateral triangle. To the bottom of said convergence electrode are glass fused three assembled electron gun members with the forward ends defined in position by said locating strips. Said assembly consists of three electron gun units prepared from stacks of electrodes and integrally fixed at the prescribed convergence angle. With such conventional electron gun assembly, there are required complicated assembling jigs to secure the convergence electrode to the three combined electron gun members in coaxial relationship and with high precision. Moreover, the assembling operation is accompanied with considerable difficulties, most likely causing the assembled electron gun members to be undesirably ill matched or damaged with the resultant occurrence of many disqualified products.

SUMMARY OF THE INVENTION It is accordingly the object of this invention to improve the construction of the convergence electrode and three electron gun members being assembled, thereby providing a triple electron gun assembly which can be integrally set up with high precision by a simple assembling operation.

In a triple electron gun assembly according to this invention, the convergence electrode is provided at the bottom with a protrusion, to which there are fitted the forward ends of the three combined electron gun members. The protrusion corresponds in size and shape with the top ends of the three electron gun units constituting the three combined electron gun members. On the edge of the protrusion are preferably formed three tongue members at an equal interval. The forward ends of the three electron gun units are also preferably provided with tongue members corresponding to those of the protrusion. The convergence electrode is fixed to the forward ends of the three assembled electron gun members by welding the tongue members of the protrusion of the convergence electrode with those of the gun members.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of the triple electron gun assembly of this invention;

FIG. 2 is a perspective view of the convergence electrode ofFIG. 1;

FIG. 3 is a perspective view of a shield member fitted to the convergence electrode of FIG. 2; and

FIG. 4 is a perspective view of the three assembled electron gun members of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates a triple electron gun assembly prepared by fitting to a convergence electrode 1 1 three electron gun members 30 consisting of three electron gun units 36 integrally put together. The convergence electrode 11 is formed into a cup-shape, and has its peripheral wall bored with three pairs of slits 12, each pair being disposed at an equal interval. Into each slit 12 is inserted a substantially L-shaped magnetic strip 13. The cup-shaped convergence electrode 11 has a protrusion 14 formed at the bottom in coaxial relationship. The protrusion 14 has three cylindrical walls 15 the axial centers of which are positioned respectively on the apices of an equilateral triangle. The protrusion 14 further has three through holes 16 bored coaxially with the cylindrical walls 15 and tongue members 17 extending outward preferably from those parts of the peripheral edge of the bottom surface 15 of the protrusion 14 which face the through holes 16 as viewed from the center of the protrusion 14. The concave portions defined by the adjacent cylindrical walls 15 have a plain surface 19, from the center of which there are cut out two mutually facing upright pieces to constitute a pair of support members 20. In that portion of the bottom of the convergence electrode 11 which faces the interspace between said support members 20 is formed a notch 21. In that portion of the peripheral edge of the forward end of the convergence electrode 11 which is disposed opposite to said notch 21 is formed a notch 22. Into the convergence electrode 11 of the aforesaid construction is inserted a shield electrode 25 illustrated in FIG. 3 consisting of three shield plates 26, which define an equal interior angle between the adjacent ones, that is, are formed in a generally Y-shape. Each shield plate 26 is formed at one end into a stepped portion, in one side of which there is cut out a notch 27. -At the outer corner of the opposite end of said shield plate 26 is integrally provided a protrusion 28 at right angles to the plane of said plate 26.

Referring to FIG. 4, a triple electron gun assembly 30 is formed of three electron gun units 36 integrally put together by glass beads 37 at a prescribed slight convergence angle to each other, each of said units 36 comprising a first cylindrical grid electrode 31 containing a cathode (not shown) and second, third, fourth and fifth

cylindrical grid electrodes

32, 33, 34 and 35 arranged coaxially with said first grid electrode 31. The outer ends of the fifth grid electrodes 35 are provided with tongue members 38 corresponding to those of the aforementioned convergence electrode 11. This triple electron gun assembly 30 is fitted to the bottom 18 of the protrusion 14 of the convergence electrode 11, in such a manner that the outer ends of the fifth grid electrodes 35 are brought into contact with said bottom 18 with the tongue members 17 of the protrusion 14 superposed on the tongue members 38 of said fifth electrodes 35. Both

groups

17 and 38 of the tongue members are welded together so as to secure the triple electron gun assembly 30 to the convergence electrode 11. The top ends of the glass beads 37 are fused jointly to fix the forward ends of the shield plates 26 disposed in the interspaces of the three pairs of the support mem-' bers 20 formed on the plain surfaces 19 of the concave portions of the protrusion 14.

There will now be described the assembling operation of the three electron gun units. The cup-shaped convergence electrode 11 shown in FIG. 2 is press molded in advance. Into said convergence electrode 11 is inserted a shield electrode 25 illustrated in FIG. 3.

One end of the stepped portion of each shield plate 26 of the shield electrode 25 is inserted between the paired support members of the convergence electrode 11. The protrusion 28 at the outer corner of the forward end of the shield plate 26 engages the notch 22 formed in the peripheral edge of the forward end of the convergence electrode 11. The convergence electrode 11 into which the shield electrode 25 has been inserted is supported by an assembling jig having three rods with said rods inserted into the through holes 16 bored in the protrusion 14 of the convergence electrode 11. Each rod of the assembling jig is made to pass through the fifth, fourth, third, second and first grid electrodes in turn with a spacer interposed therebetween. Between the adjacent stacks of electrodes into which the rods of the assembling jig have been inserted are provided glass beads 37, which integrally fix the electrode stacks by being fused to the outer ends of mounting brackets 39 attached to the respective grid electrodes 31 to 35. At this time the glass beads are also fused to the support strips 20 formed on the plain surfaces 19 of the protrusion 14' to support the convergence electrode 11 and part of the rear end of each shield plate 26 as well as to said mounting brackets 39. After the assembling jig is removed, there is inserted a magnetic strip 13 into each of the three pairs of slits 12 formed in the peripheral walls of the convergence electrode 11, and there is received a cathode in the first grid electrode, thus completing a triple electron gun assembly.

What is claimed is:

1. A triple electron gun assembly comprising:

three electron gun units, each including a plurality of coaxially arranged grid electrodes, the central axes of said gun units being arranged to form the apices of an equilateral triangle;

glass beads provided between the adjacent electron gun units so as to integrally fix said electron gun units together;

a cupshaped convergence electrode having a protrusion at the bottom thereof which has a surface mating with the top end of the three electron gun units and locating the three electron gun units so as to provide convergent electron beams, said protrusion having three apertures therein located along the central axes of respective ones of the electron gun units for passing the electron beams from said respective electron gun. units, said protrusion including three substantially cylindrical walls corresponding substantially to the outline of the mating surfaces of said three electron gun units and three substantially flat surfaces formed in the three concave portions defined by the adjacent walls of said cylindrical walls, said glass beads being attached to the respective substantially flat surfaces, the lower surface of said protrusion being fitted to the top mating ends of the electron gun units so as to facilitate accurate positioning and attaching of said electron gun units to said convergence electrode.

2. The triple electron gun assembly according to claim 1 wherein upright support strips are formed in said substantially flat surfaces.

3. The triple electron gun assembly according to claim 1 wherein the cylindrical walls have tongue members formed on the peripheral edge; the electron gun units have tongue members formed at the forward ends in corresponding relationship to those of the cylindrical walls; and the protrusion and electron gun units are so arranged that respective tongue members of the former are superposed on those of the latter, both groups of tongue members being welded together to secure said electron gun units to said cupshaped convergence electrode.

4. The triple electron gun assembly according to claim 2 wherein said grid electrodes have mounting brackets, and the glass beads are fused to the support strips of the convergence electrode and to said mounting brackets of said grid electrodes so as to jointly support them.

5. The triple electron gun assembly according to claim 2 wherein said three substantially flat surfaces have cut-out portions, the remaining portion of each of said substantially flat surfaces defining said upright support strips.

Claims

1. A triple electron gun assembly comprising: three electron gun units, each including a plurality of coaxially arranged grid electrodes, the central axes of said gun units being arranged to form the apices of an equilateral triangle; glass beads provided between the adjacent electron gun units so as to integrally fix said electron gun units together; a cupshaped convergence electrode having a protrusion at the bottom thereof which has a surface mating with the top end of the three electron gun units and locating the three electron gun units so as to provide convergent electron beams, said protrusion having three apertures therein located along the central axes of respective ones of the electron gun units for passing the electron beams from said respective electron gun units, said protrusion including three substantially cylindrical walls corresponding substantially to the outline of the mating surfaces of said three electron gun units and three substantially flat surfaces formed in the three concave portions defined by the adjacent walls of said cylindrical walls, said glass beads being attached to the respective substantially flat surfaces, the lower surface of said protrusion being fitted to the top mating ends of the electron gun units so as to facilitate accurate positioning and attaching of said electron gun units to said convergence electrode.