US3543071A - Electrode with wing-shaped brackes for cathode ray tubes - Google Patents

Description

Nov. 24, 1970 J. H. JOHNSON ELECTRODE WITH WING-SHAPED BRACKETS FOR CATHODE RAY TUBES Filed Oct. 14, 1968 INVENTOR JAY H. JOHNSON ATTORNEY United States Patent US. Cl. 31382 8 Claims ABSTRACT OF THE DISCLOSURE A cylindrical electrode is provided for cathode ray tube electron guns with two normally disposed bracket members adapted to enter a mounting bead and which extend from a rolled over edge of cylindrical tubing bent back to form a coaxial skirt about the cylindrical electrode body.

This invention relates to cathode ray tube electrodes and more particularly to color tube cylindrical electrodes having brackets affixed thereto.

In the development of electron gun assemblies for color picture tubes having three separate electron gun assemblies it has been customary to retain electrodes of three separate guns in fixed position by holding the electrodes in three separate glass beads by means of mounting straps welded onto the cylindrical electrode structures. A single strap curved about each electrode and welded thereto similar in principle to that of the US. Pat. No. 2,909,689 has been employed with extending end clamps oriented to permit side by side electrodes to be mounted into a single glass bead. However, such construction requires critical shaping of the strap to conform exactly with the outer cylindrical curvature of the cylindrical electrode. Since the straps are formed and tempered in large quantities and metal has elastic properties not always retaining its shaped form, and because such straps are exposed both in tempering and in use to high heats that tend to warp or twist the metal it has been almost impossible to conform the shape of the strap exactly with that of the cylindrical electrode. In consequence, when spot welding techniques are used, a strap that is forced into place and held by three or more spot welds tends to fail when put under thermal and mechanical stresses. The choice of more than one Welding point about the circumference of the cylindrical surface requires almost perfect fit to prevent some sort of stress during the spot welding operation. Gaps of spacing of brackets, weld splashes in mounting them and distorted electrode cylinder surfaces contribute to corona and arcing in high voltage CRT electrodes. Yet in the prior art for color guns it has been customary to employ these contoured strap configurations, because they have been less susceptible to failure through welding puddles and splashes than pin type brackets or those butt welded onto an electrode cylinder.

Other electron gun structures for cathode ray tubes combining several beams within a single electrode and also plate like substantially planar electrodes are known. In these electrodes there is a similar problem of mounting firmly and exactly in an immovable position by extending a bracket into a glass mounting bead. Not always are these structures adaptable to the use of straplike brackets. Thus a single technique useful for improved mounting in a variety of electrode configurations is not generally available in the prior art.

Another factor desirable in multiple beam guns is to provide a mounting configuration which prevents arcing between electrodes in the various guns. It has been ice difficult with some configurations to separate the brackets from each other by any significant distance, and large close parallel surfaces can introduce enough capacitance to provide limitations in electrical performance.

Any bracket configuration provided must be firm and affixed to the electrode in such a manner to hold the electrode in precise position without movement in the presence of significant thermal and physical stresses, such as that permitted by weld failures and surface flexing.

Accordingly it is a general object of this invention to provide a new article of manufacture comprising a cathode ray electrode of novel configuration solving the foregoing problems of the prior art.

A more specific object of the invention is to provide suitable mounting brackets for color television electrodes which are integrally formed to extend from exterior surface of the cylindrical electrodes.

A further object of the invention is to produce mouning brackets for color television electrodes of integral construction in such form to make them less critical in construction and at the same time improving their functional performance and strength by holding the electrodes in the mounting bead in two dimensions.

Another object of the invention is to provide mounting brackets for multiple beam electron gun electrodes affording less reaction between electrodes in the separate guns.

Still another object of the invention is to provide universal type mounting brackets useful on a variety of different electrode configurations.

In particular it is an object of this invention to produce mounting brackets for high voltage cathode ray electrodes which reduce possibilities of failure through arcing, corona or electrical leakage.

Thus, in accordance with the invention, a cylindrical electrode structure is provided with integral mounting tabs in the form of at least two wing members extending from and integral with the electrode structure. They may extend from a rolled over skirt portion disposed coaxially alongside a narrow portion at one end of the cylindrical electrode tubing to form a claw member for protruding into a glass mounting head. The claw member is shaped to enter the glass bead in two normal planar sheets, one of which extends a significant distance along the axial length of the electrode, and is preferably disposed to mount the electrode substantially symmetrically about the center of gravity of the electrode. The bracket is so located on the circumference of the electrode to extend outwardly generally radially toward one edge of the bead and shaply deviates at an angle into the bead to thereby space adjacent portions of bracket members from different electrodes entering the same bead at greater distances than conventional with prior art strap structures.

The foregoing objectives together with further features and advantages of the invention are set forth hereinafter by reference to the embodiment of the invention shown in the accompanying drawing, wherein:

FIG. 1 is an elevation fragmentary view, in section of a CRT grid electrode structure as positioned in an electron gun with mounting brackets engaging a glass bead member.

FIG. 2 is a plan view of the electrode structure of FIG. 1, and

FIG. 3 is an elevation view in section of a further CRT grid structure embodying the invention.

As may be seen from the embodiment of FIGS. 1 and 2, a CRT first grid electrode 5 is formed of a cylindrical tubing 7 with a closed end, cup shaped member 6 having a single beam passageway along axis 8 passing through aperture 9. The cylinder is rolled over at end to form a narrow skirt portion 11 outside of and generally coaxial with the cylinder tubing 7.

Extending from the skirt portion 11 substantially normally with the axis 8 is a first planar member 12 of a mounting bracket bent to form a perpendicular planar claw member 14 extending alongside the electrode generally parallel with the axis 8. The claw member has an indentation 15 for grasping the glass bead member 16 to hold the electrode in place in a gun assembly (not shown) in a critical position relative to the other adjacent electrodes.

In order to precisely mount and hold a cathode ray tube electrode without tilting or moving during any physical stresses caused by fields, beams, heat changes or mechchanical forces encountered after manufacture of the electron gun, the wing-shaped claw member 12-14 is integral with the electrode and extends beyond the electrode to engage the glass head 16 in two substantially normal planes, one of which extends in a plane normal to the beam axis and the other of which is disposed a significant length parallel to the axis 8 of the cylindrical electrode 5. This gives firmness and removes the tendency to twist and warp that results when a bracket claw is disposed along a single plane.

Furthermore there are no welds, and the narrow skirt portion 11 is strong and firm to hold the claw members 12-14 in perfect registration from one electrode to the next. In order to alleviate any tendency for the electrode to move or twist on its axis, the planar claw member 14 having indentation 15 is disposed on opposite sides of the plane of center of gravity 20 of the electrode.

The criticality of dimensioning is even more important in the case of three gun color picture tubes, since all three guns must register with each other to form a set of beams commonly swept by a deflection system (not shown). In such guns two planar members are disposed at angles of substantially 120 as indicated by angle x, and adjacent electrodes noted by primed reference numbers are mounted in common glass beads 16 by their wing-shaped claw bracket members 12-14 as indicated in FIG. 2.

As may be seen, the planar extension 12 integrally connected to the electrode extends beyond its confines in a substantially radial direction at positions such that the general orientation of the planar portion 12 changes its direction to dispose face-to-face the axial end plate members 14 in the region of the bead. This construction keeps the capacitance between the brackets low and the distancesparticularly in air-between two adjacent brackets remote to improve functional performance by reducing feed through discharges due to arcing, etc.

This mounting structure is useful in the various other tubular electrodes of an electron gun, as for example in the third grid structure shown in FIG. 3. The use of common reference characters here identifies corresponding portions of the electrode structure which is substantially different in that the cylindrical electrode has its tubing portion formed with two different diameters 26 and 27.

Typical inner diameters of cylindrical electrodes constructed in this way may range in the order of .250 to .400 inch, and the overall lengths range in the order of .220 to 1.000 inch, but other dimensions may also be used if desirable. In these ranges the skirt may have a radius of .015 inch and the axial length of the claw member 14 may be in the range of .150 to .300 inch.

It is clear that the foregoing construction is novel and provides advantageous performance in the critical environ- 4 ment encountered in electron gun assemblies. Therefore those features of novelty believed descriptive of the spirit and nature of this invention are defined with particularity in the appended claims, for which Letters Patent are petitioned.

What is claimed is:

1. An electrode for a cathode ray tube electron gun with a mounting bead holding a series of beam processing electrodes in precisely spaced positions comprising at least one aperture for passing an electron beam along an axis and affecting its eletcrical characteristics, at least a pair of wing-shaped plate members extending integrally from the electrode substantially normally with the beam axis, each being formed at one end with a member adapted to grip said electron gun mounting bead and forming an angle with two components normal to each other and extending respectively generally perpendicular to and generally parallel with the axis of the beam, wherein each said wing-shaped member is so dimensioned and disposed to engage with said two components a mounting head to support in two substantially normal planes one of which extends a significant length parallel to the axis of the beam.

2. An electrode as defined in claim 1 having a closed cylindrical cup configuration with at least one axial aperture therein.

6. An electrode as defined in claim 2 wherein the cylindrical electrode is generally formed to have two different diameters along the axial dimension.

4. An electrode as defined in claim 1 wherein the wingshaped plate members are limited to two with a planar member generally extending at intervals about the electrode.

5. An electrode as defined in claim 4 wherein the two wing-shaped members are spaced about the electrode at positions where a portion of the plate member near the electrode extends substantially radially from the beam axis and its remote end changes direction toward the position of a glass bead in its mounted position.

6. An electrode as defined in claim 1 wherein a planar claw member extends alongside said electrode disposed on opposite sides of the center of gravity of the electrode and oriented to enter a mounting bead generally parallel to said beam axis.

7. An electrode as defined in claim 1 wherein the electrode is a generally cylindrical tubing with one end thereof rolled over to produce a narrow skirt portion outside of and generally coaxial with said cylindrical tubing, and said plate members extend normally to the beam axis from the skirt portion to project the component of the plate member which is parallel with the axis of the beam alongside the electrode body for a substantial portion of its length.

8. An electrode as defined in claim 7 wherein the component parallel to the axis of the beam is disposed to mount the electrode at its center of gravity.

References Cited UNITED STATES PATENTS 2,909,689 10/1959 Case 3l3-256 X 2,942,128 6/1960 Johnson 3 l382 3,239,708 3/1966 Johnson 31'382 3,265,920 8/1966 Fiore 3l382 X JAMES W. LAWRENCE, Primary Examiner V. LAERANCHI, Assistant Examiner U.S. Cl. X.R. 313-256, 289, 356

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