US2821644A - Mountings for picture tube grids - Google Patents

Description

Jan. 28, 1958 K, MI HENRY E 2,821,644 I MOUNTINGS FOR PICTURE TUBE GRI DS 4 Sheet-Sheet 1 Filed Nov. 10, 1954 INVENTORS KENETH M.HENRY HARVARD B.V|NCENT ATTORNEYS 1958 K. M. HENRY ET AL 2,821,644

MOUNTINGS FOR PICTURE TUBE cams 4 Sheets- Sheet 2 Filed Nov. 10, 1954 Ill I i 3 m I INVENTORS I KENETH M. HENRY BY HARVARD BfiVlNC ZEN'T mw7 ATTORNEYS Jan. 28, 1958 K. M. HENRY ETAL MOUNTINGS FOR PICTURE TUBE GRIDS 4 Sheets-Sheet 4 Filed Nov. 10, 1954 INVENTORS KENETH M. HEN RY BY 7 HARVARD B.V|NCENT ww ATTORNEYS United States Patent C) MOUNTINGS FOR PICTURE TUBE GRIDS Kenneth M. Henry and Harvard B. Vincent, Toledo, Ohio, assignors to Owens-Illinois Glass Company, a corporation of Ohio Application November 10, 1954, Serial No. 467,960

11 Claims. (Cl. 313-78) Our invention relates to picture tubes. It provides new and improved means for mounting grids in cathode ray tubes and in certain forms thereof is particularly adapted for use in color television.

In picture tubes for color television as they are commonly constructed at the present day, the grid structure which controls the color registry is supported on a frame of substantial width which must be contained within the envelope, thereby making the area in which the picture may be produced substantially smaller than the face of the tube. If the width of the frame is decreased its stiffness becomes inadequate for end use.

An object of the present invention is to provide an improved construction by which the area available for the picture is increased to substantially the full area of the face plate of the picture tube.

The invention provides a construction in which. relatively thin metal frame members or strips of sheet material are extended along the inner marginal surfaces of the face plate and bonded thereto. Such strips provide a frame or support for the fine wires forming the grid. Owing to the method of attachment of the strips to the envelope of the tube, they are of adequate stifiness to serve the requirements of end use and at the same time provide for a comparatively large picture area. the purpose of attaching the grid wires to the supporting strips the latter may have an edge portion offset or bent to U-form and slotted to form rows of lugs or hooks for holding the grid wires or strands, the lugs and spacing slots being of a width corresponding to the required spacing of the grid wires.

In one form of our invention the grid supporting strips overlie and are adhered to the inner wall surfaces of the marginal flange of the face plate. strips may be attached to the enclosing envelope by means of either solid or tubular studs sealed in the walls of the picture tube, the grid frame or strips being anchored to the studs.

For

In other forms the The grids as mounted in the tubes or envelopes are Fig. 3 is a fragmentary perspective view showrng a grid supporting strip mounted on the face plate of the tube;

Fig. 4 is a view similar to Fig. 2, showing .a modified form of grid supporting strip;

Fig. 5 is a fragmentary diagrammatic plan view ofthe grid and supporting strips;

ing strips as seen in side elevation;

Fig. 7 is a fragmentary perspective view of the grid supporting strips shown in Figs. 46;

Fig. 8 is a view similar to Fig. 4 showing a further modification of the means for mounting the grid;

Figs. 9, 10, and 11 are fragmentary views illustrating various alternate means for attaching the grid supporting strips to the face plate;

. Fig. 12 is afragmentary view Showing a further modification comprising a solid stud by which the grid frameis anchored to the face plate;

Fig. 13 is a fragmentary perspective view of a metal form or strip for carrying the grid;

Figs. 14 and 15 are fragmentary views similar to Fig. 12 showing further modifications of the grid mounting means; and

Fig. 16 is a view of a plural strip supporting frame for the grids.

Referring to Figs. 1, 2 and 3, which illustrate one form of our invention, the picture tube comprises a funnel-shaped body 20, stem 21 and a face plate 22 made of glass and sealed to the body along the line 23. The face plate may be of conventional, substantially rectangular, elongated form as viewed in plan. The face plate is convex and formed with a marginal flange 24 to which Each strip 26 has its upper marginal portion bent or curved inwardly in the form of an inverted U. Slots 28 divide this margin into a multiplicity of narrowly spaced lugs or hooks 29 which anchor the screen wires and hold them in narrowly spaced parallel relation.

The means for securing the strips 26 to the face plate includes a sheet or layer 31 of felt or the like cemented to the rear surface of the strip 26. A sheet or layer 32 of suitable bonding material between the felt 31 and the face plate provides a means for securing the strip 26 to the face plate. The layer 32 may consist of a frit.

A further specific method of bonding the thin metal strips to the wall surface of the face plate consists in coating one or both of these parts, over suitable areas, with a brazing glass which melts and adheres at a temperature below the temperature at which distortion of the face plate becomes a serious problem. This brazing glass should be one which will not soften and permit the metal to pull away'from the glass at a temperature of 750 F., to which temperature the assembly may be heated by the tube manufacturer during his processing.

Brazing glass as herein referred to includes any compound of metallic oxides suitable for this purpose. Following the application of the brazing glass the face plate and the thin metal strips are assembled in a fixture which serves to locate and seat the metal strips as the assembly is heated in an oven to a temperature at which the brazing glass melts and adheres.

As a further modification of the strip attaching means,"

the inner face of the side wall or flange 24 may be metallized by the use of a silvery compound such as may be obtained on the open market. This area may then be electroplated and the grid supporting strip 26 attached thereto by soldering. A solder having a high softening point .should be used to withstand the high temperature to which the tube is subjected during manufacturing or assembling operations. Such softening point should prefr'erably be above 750 F.- f I Patent ed Jan. 28, 1958 Figs. 4-7 illustrate a modified construction for mounting two insulated grids in the face plate. These are adapted for use in tubes employing chromatic color design. In this construction upper and lower mounting strips 35 and 36 are attached to the inner face of the flange 24. These strips are separated by a baresurface strip 37 of the glass face plate which forms an insulating area. The grid frames 35 and 36' may be attached to the face plate in the same manner as above described in connection with Fig. 3, including the layers 31 and 32. The lower grid frame or strip 36 may be substantially similar to the structure shown in Fig. 3, the upper portion of the strip being bent to U-forrn and comprising downwardly extending lugs or hooks 37 spaced apart by slots 38. The upper grid plate 35 has its lower portion offset inwardly and is slotted to provide downwardly'extending lugs or hooks 39 spaced apart by slots 40. As shown diagrammatically in Fig. 5, the upper lugs 39 may be offset laterally with respect to the lower lugs 37 so that the wires 42 forming one of the grids alternate with the wire 43 (shown in broken lines) forming the other grid, the alternate wires being equally spaced apart. The lower ends of the upper lugs 39 are formed with upwardly curved surfaces 44 which may assist in holding the wires 43 in the uniformly spaced position between the wires 42. The two grids or sets of wires 42, 43 are held in the same plane or at a common level by the interwoven wires or strands 46 of glass or other insulating material.

The grid wires are narrowly spaced. For example, they may have a spacing of .030". The screen plate behind them (not shown) is provided, forv example, with stripes of phosphor .015" wide fluorescing in the colors .in the usual sequence, red, green, blue, green, red.

Figs. 9, 10 and 11 illustrate various alternate structures for attaching the grid supporting strips to the face plate. Referring particularly to Fig. 9, a cylindricalmetal tube 50 is mounted in the flange portion 24 of the face plate, a bolt 51 extends through a restricted opening in the inner end of the cylinder 50, the head 52 of the bolt being within the cylinder and bearing against the end wall of the cylinder. The bolt has a screw-threaded connection with the strip 26. Thismay comprise a nut 53 welded to the strip and in which the bolt is threaded. The cylinder 50 is mounted within a cylindrical opening 54 extending through the wall of the face plate. The cylinder is preferably attached by fusion to the wall surface of the opening 54. The screw head is provided with a kerf 56 to receive a tool extended through the open cylinder for attaching and adjusting the bolt to the nut 53. Following the installation of the grid the outer end .of the cylinder is closed by a disk 57 which is soldered in place. Theisolder should have a softening point, preferably higher than 750 F. which is the usual baking temperature at which the assembly will be heated by the tube maker during processing. A,plurality of these tube assemblies arerused for the attachment of .each of the strips 26. These attachments may be located at intervals lengthwise of the strip as indicated diagrammatically on Fig. 8, at the intersecting points of the broken line 58 extending 'lengthwiseof the strip and the cross lines 59.-

Fig. 10 illustrates a modification of-the structure shown in Fig. 9, adapted for use with two grids .such; as heretofore described in connectionwith Figs. 4-7. Intthisistructure the nut 53 is attached to the frontfaceofatheastrip 26. A second strip 26* is mounted behind the strip. 26 for attachment of the wiresforming'the secondgrid. The strip 26 may be made-of. insulating material.

In Fig. 11 a grid supportingstrip 26! is weldedor brazed tothe front face of thenut -3 andinsulatedfromthe:strip 26. 'In each of the structures shown inEigs. 9., and '11, the boltserves asa tension :and takeupmeans between the tubes and strips 26 :for applying tension to the grid wires.

Figs. 12-16 illustrate further modified constructions 4 in which solid, cylindrical metal studs 60 are employed for attaching the grid frames or strips to the face plate. The studs 60 consist of a metal matching the glass for expansion characteristics, the studs being soldered by fusion at suitable intervals along the two opposite sides of the face plate 26. As shown in Fig. 12 the opening in which the stud is mounted extends only part way through the glass wall. Each stud is formed adjacent to its exposed end with a groove 61. The strip 26 is formed with slots 62 to receive the studs 60, with the side walls of the slots in the grooves 61. The, slots'are spaced to correspond with the spacing of the studs. Slotted spring washers 63 are mounted, on the strips 26 and serve to hold the strips in position on the studs.

Fig. 14 illustrates a mounting for plural grids. Such mounting includes the strips 26 and 26 In this construction the slots are formed in the strip 26 for attaching the assembled strips to the studs60. The strips 26 and 26 may be spacedapart and insulated from each other by an interposedstr'ip 64" of insulating material. As shown in Fig. 14 the face plate is formed with openings 54 extending entirely through the glass wall.

Figs. 15 andl6illustrate a mounting for plural grids in which the strips 26 and.2 6 are both formed with slots permittingthem to be mounted on the studs 60. In this structure the strip 26 is positioned behind the strip 26, that is, interposed'between the strip 26'and the glass wall. A sleeve 65 'of insulating material is mounted on the stud 60. Insulating strips or washers 66 may be interposed'between the strips 26' and 26 The spring washers 63 in this form of mounting are positioned in front of the grid supportingstr'ips. The lugs .37'and 39 on the strips 26 and 26 may be arranged in staggered relation as above described in connection with Figs. 5-7.

Modifications may be resorted to within the spirit and scope of our invention.

We claim:

1. A picture tube comprising an envelope, a grid therein and means for attaching the grid to the walls of the envelope, the attaching means comprising strips of thin sheet material extending along the said walls with a major portion of each strip lying flat against the side walls, and means for anchoring'said strips to said walls, the grid comprising a multiplicity of narrowly spaced fine strands anchored to said strips, the said major portions of said strips being substantially perpendicular to the grid strands.

2. The picture tube definedin claim 1, the said attaching strips each having a marginal portion thereof offset and slotted to form a multiplicity of spaced lugs in a row extending lengthwise of the strip and by which the gridstrands are held.

3. The picture tube defined in claim 2, the said marginal portions of the strips being bent to substantially U-form, the said lugs and slots being of approximately equal width and holding the said grid strands narrowly and equally spaced.

4; The picture tube defined in claim 1, the envelope consisting ofglass, the said strips consisting of'sheet metal, and a layer of bonding material interposed between the said strips andthe wall surfaces of the envelope and forming a bondhetween said strips and envelope.

5. Theapparatus defined in claim 4, said bonding material comprising a frit.

6. The combination set forth in claim 1, the said strips consisting 'of metal welded to theinner wall surfaces ofthe envelope.

7. A picture tube comprising a body and a face plate formed with a peripheral flange, a grid mounted within the tube, means for attaching the grid to the face plate comprising sheet metal strips extending lengthwise along opposite wall surfaces of said flange, means for anchoring said strips tosaid flange, each said strip having a marginal portion extending lengthwise thereof and offset inwardly from the body 'of the strip, the saidbody of the strip lying flat against the flange throughout its area, said offset portion being slotted to form a multiplicity of lugs with interposed spaces substantially equal in width to the lugs, the grid comprising a multiplicity of fine wires anchored to said lugs.

8. A picture tube comprising an envelope, grids mounted therein, each grid comprising a multiplicity of parallel strands, means for attaching the grids to the walls of the picture tube, said attaching means comprising pairs of parallel strips of sheet metal extending along and parallel with inner wall surfaces of the envelope, the strands forming one of said grids being attached to one pair of said strips, the strands forming the other grid being attached to another pair of said strips, each of the strips being formed with a multiplicity of narrow, narrowly spaced lugs to which the grid strands are anchored and by which the strands are held uniformly and narrowly spaced apart, and means for holding the strands of the two grids in the same plane, said plane being perpendicular to the body portions of said strips.

9. The apparatus defined in claim 8, the said lugs on one pair of said strips being in staggered relation to the lugs on the other pair of strips, the strands of one grid alternating with those of the other.

10. The apparatus defined in claim 8, the said attaching strips being in parallel relation to the adjoining surfaces of the envelope and a layer of bonding material between each strip and the envelope by which said strips are bonded and rigidly adhered to the wall of the envelope.

11. The apparatus defined in claim 8, the said walls of the envelope consisting of glass, the said strips consisting of metal, the strips to which the strands of one grid are attached lying substantially in the same plane as the corresponding strips to which the strands of the other grid are attached, the said strips being spaced apart with an interposed bare strip surface of the glass envelope insulating the strips of one grid from those of the other.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,735 Olson Nov. 10, 1953 2,540,835 Anderson Feb. 6, 1951 2,546,828 Levy Mar. 27, 1951 2,682,620 Sanford June 29, 1954 2,695,372 Lawrence Nov. 23, 1954 2,711,493 Lawrence June 21, 1955

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