US3394279A - Support and electrical connection for grid cup in electron gun - Google Patents

Description

July 23, 1968 YORNS ETAL 3,394,279

SUPPORT AND ELECTRICAL CONNECTION FOR GRID CUP IN ELECTRON GUN Filed March 23, 1967 INVENTORS EDWARD E.YORNS JAY H. JOHNSON BY Wm May ATTORN United States Patent 3,394,279 SUPPORT AND ELECTRICAL CONNECTION FOR GRID CUP IN ELECTRON GUN Edward E. Yorns and Jay H. Johnson, Owensboro, Ky., assignors to Kentucky Electronics, Inc., Owensboro, Ky., a corporation of Delaware Filed Mar. 23, 1967, Ser. No. 625,529 2 Claims. (Cl. 313-82) ABSTRACT OF THE DISCLOSURE A cathode ray tube electrode structure is disclosed, which comprises a cup-shaped electrode with a connection tab extending from a rim to engage a lead in the glass stem of the cathode ray tube which usually is a round wire. The tab is typically shaped as a split cylinder, preferably affording a tight fit upon the stem for engaging a portion thereof to hold it firmly and mechanically in place. The stem and tab are welded as the various electrodes are aligned along the electron beam axis.

This invention relates to electrode structure and, more particularly, it relates to structure for electrically connecting electronic circuits to an electrode disposed within a cathode ray tube.

Within a cathode ray tube it is customary to support electron guns on stem leads extending through a glass stem or base which closes the tube envelope at the end of a long neck in which the gun resides. These stem leads serve both the purpose of mechanically supporting the gun and electrically connecting the various electrodes to external electronic circuits. In tube operation there are thermionic heaters disposed close to the stem which provides significant thermal stresses to mechanical joints, generally simple spot welds, between the stem leads and the electrodes.

Conventionally, various schemes of interconnecting the stem leads with the electrodes have been used, and for this purpose a tab is generally welded to the electrode for disposing adjacent to and spot welding to the stem wire. This causes a series of several welds in the electrical connections which can cause excessive resistance if the welding is faulty, and may furthermore cause a disengagement of the spot welds because of thermal and mechanical stresses. In addition, the spot welds are generally manually done so that uniformity may not be good in either the placement of the weld for best electrical or mechanical operation. For these reasons conventional electrode assemblies are expensive to make, result in occasional rejects, and give a risk of failure during operation.

It is therefore an object of the present invention to provide improved electrode structures in cathode ray tubes.

A more specific object of the invention is to produce better mechanical and electrical connections between the electrodes and the stern assembly of a cathode ray tube.

Another object of the invention is to produce electrode structure for an electron gun which requires fewer welding operations.

Accordingly, the present invention provides a cylindrical electrode within an electron gun that has an integral connection tab extending therefrom which is welded to the glass stem lead to support the electron gun assembly and make electrical connections therewith. Preferably, the integral connecting tab has a clamping structure such as a split cylindrical sheath for elastically encompassing a portion of the stern lead in good mechanical contact, and which may be welded in place to firmly establish a permanent gun positioning.

3,394,279 Patented July 23, 1968 The foregoing features and objects are supplemented in the more detailed description of the invention as illustrated by the specific embodiments referred to in the accompanying drawings, in which:

FIGURE 1 is a fragmentary view in perspective of an electron gun incorporating the invention,

FIGURE 2 is a plan view of an electrode constructed in accordance with this invention, and

FIGURE 3 is an elevation view of a further embodiment of the invention.

As seen in FIGURE 1, an electron gun 5 is generally mounted upon the glass stem or base 6 by means of mechanical coupling between at least the first grid electrode 7 and the stem lead 8. The electron gun 5 has a series of other electrodes 9, 10, etc. mechanically aligned by means of brackets 11 extending into a glass head 12 for a unitary electron gun assembly sitting upon several of the stern leads such as 8.

The first grid electrode 7, which is a generally cylindrical cup-shaped electrode having an aperture 15 for passing an electron beam along axis 16, is constructed by this invention to have extending from its rolled over external rim 17 a connection tab 18. In this embodiment the tab is formed to extend parallel to the axis 16 up alongside the body of the first grid electrode 7. It is further shaped to provide a generally split cylinder clamp structure 20 for receiving and holding the round wire stem 8 with a firm mechanical coupling. For this purpose, preferably the inside diameter of the split cylinder 20 is slightly less than the diameter of the stem wire 8.

The tab extension clamp 20 is spot welded to the stem lead 8 at one or more points 22 depending upon optimum electrical and mechanical requirements. The stem 8 may be bent or shaped to fit the position of the grid 7 as desired, and in the case of a three gun color tube, at least three firm first grid mounting positions are provided to produce substantial support for holding the gun in mechanical alignment.

As may be seen from the plan view of grid electrode 7' in FIGURE 2, the tab 18' extends radially from rim 17. Preferably it is formed with clamping structure such as shown in FIGURE 1 which permits the gun to slip onto stem leads disposed generally axially alongside the electrode body. However, other structures: may be desirable such as that shown in FIGURE 3, where the stem 8' is bent normally to engage the rolled over tab 25 which provides an alternative form of the generally split cylinder clamp to extend generally normally from the axis 16 of the electron beam.

The tabs may be either preformed in substantially final form, or they may be partially formed for final shaping during the welding operation if desired. In this case, the electrode structure would be either a generally fiat tab or would be partially formed to loosely enclose or clamp the stem lead. In general, a single welding operation is all that is required, since no tab need be welded on the electrode structure.

It is evident that some variations may be made from the embodiments shown which do not depart from the spirit or the scope of the invention which is represented in the appended claims.

What is claimed is:

1. A grid cup electrode assembly for the electron gun of a cathode ray tube comprising in combination, a generally cylindrical single piece cup-shaped electrode with an axial aperture for passing an electron beam, a rim extending externally about the open mouth of said cup-shaped electrode, a mounting bracket affixed to said electrode for positioning and holding it in an electron gun assembly, said cup-shaped electrode being the first grid 3 in said electron gun assembly, an integral lead connecting tab extending from the rim of said cup-shaped electrode and having a longitudinal portion in the form of a slitted cylinder disposed axially in a direction parallel to said electron beam, a glass stem having at least one conductive lead extending therethrough, said lead being a circular Wire Whose end remote from said stem is enclosed within and secured to said slitted cylinder by a single conductive connection.

2. An assembly as defined in claim 1, wherein the shaped structure is disposed alongside the exterior of said electrode.

References Cited UNITED STATES PATENTS ROBERT SEGAL, Primary Examiner.

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