DE2840211A1 - Convergence and purity control for colour TV CRT - has two pairs of U=shaped magnets in cup, magnetised from outside, to control beams from three electron guns - Google Patents

Abstract

The picture tube has three electron guns in a plane and a convergence cup common to all three electron beams. Permanent magnets in the tube neck and magnetised from the outside to certain intensities and act on the electron beams. Their fields adjust the three beams individually and independently from each other. Two pairs of U-shaped permanent magnets (3, 4, 6, 7) are mounted in the convergence cup. They are positioned on the horizontal axis (5) connecting the three electron beams, and on the vertical axis (8) passing through the middle beam in a vertical plane perpendicular to it.

Description

Device for setting convergence and color purity

called a color picture tube.

The invention relates to a device for adjusting convergence and color purity of a color picture tube according to the preamble of the first claim.

Such devices currently consist of on the Tube neck arranged, firmly magnetized rings, which are used to adjust convergence and color purity are twisted against each other. However, efforts are now being made the deflection system to increase the deflection sensitivity over a large part of the Neck at about the center of the electron gun. The device for setting convergence and color purity must then either above the deflector or in the tube neck.

Accommodation arrangements in the tube neck are from DE-OS 26 12 607 known and others are in the older German patent application P 27 22 1177.7 has been proposed. In DE-OS 26 12 607 one is on the electron gun Fixed metallic permanent magnet ring with air gap used. Because this ring surrounding all three electron beams in common with relatively large girth, it is with this arrangement it is not possible to separate the electron beams individually and essentially to be influenced independently of each other. This makes it difficult to adjust the convergence considerable.

If, for example, an outer ray and the central ray have already converged, so this outer ray loses its convergence again when the other outer ray is corrected. An approximation in many setting steps is necessary.

In the German patent application P 27 22 477.7 a device with eight permanently magnetic, externally magnetizable, in the electron beam generation system attached pieces of wire described. This device allows the electron beams individually influencing.

However, it has been found that it is very difficult to do this To secure pieces of wire stably against later changes in position to parts of the system. However, it is imperative that once magnetization is not carried out only in the strength but also in the position of their poles is preserved.

The object is therefore to provide a device for the rapid adjustment of To create convergence and color purity with a single influence of the electron beams is possible and at the same time ensures a mechanically very stable structure.

The solution to the problem can be found in the claims.

This solution not only ensures a very stable structure of the Device and a largely independent setting of the external jets, but through the two permanent magnets arranged in the vertical axis is beyond that a very simple joint shifting of all beams for color adjustment is possible.

The invention is explained below using the example in FIGS and 2 explained in more detail. They show: FIG. 1: The setting of the convergence figure 2: The adjustment of the color purity Figure 1 shows a section by an electron beam generating system arranged in a tube neck 1 at the level of the convergence pot 2 common to the three electron beams R, G, B U-shaped permanent magnets 3.4 according to the invention in the horizontal axis 5 and the corresponding permanent magnets 6 and 7 in the vertical axis 8 are with their legs inserted through holes 9 in the wall of the convergence pot and with from the wall of the Convergence pot set punched out tabs (10) and so positionally stable with the System connected.

The permanent magnets are activated by the magnetizing device 11 from the outside magnetized.

In the example shown, the permanent magnet 3, on the right, is magnetized so that the legs have the same polarity and the middle piece the opposite polarity This means that at the location of the electron beam surrounded by the U-shaped permanent magnet 3 B generates a field approximately parallel to the legs of the U and the horizontal axis 5, which the electron beam in the direction of the vertical axis, in Figure 1 e.g. down, distracts.

When the left U-shaped permanent magnet 4, the legs are opposite Poles magnetized. The magnetic field generated thereby runs approximately in the direction of vertical axis 8 and directs the electron beam R parallel to the horizontal axis 5, in this example away from G.

With the permanent magnets 3 and 4, it is possible as described, the External rays independently of one another in the direction of vertical and horizontal To move the axis and thus to converge on the center beam.

For the common movement of all three beams in the horizontal direction, i.e. permanent magnets 6 and 7 are used to adjust the color purity. This is in Figure 2 illustrates.

The legs of the upper permanent magnet have the opposite polarity like the legs of the lower permanent magnet. This creates a magnetic field in the vertical axis which the electron beams in common in the horizontal axis distracts. The distance between the two U-shaped permanent skimmers lying in the vertical axis (6,7) is chosen so that all three electron beams have the same magnetic Forces work.

In the exemplary embodiment, the distance is approximately 40 greater than the mutual Distance of the electron beams shown at this point.

Thick permanent magnetic metal bracket 3, lot and 6.7 are appropriate made from pieces of wire or ribbon material. Of course, the Arrangement also with electron guns with oval instead of - as drawn circular Grids are used.

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Claims (2)

Device for setting the convergence and color purity of a Color picture tube. Claims 1. Device for adjusting convergence and Color purity of a color picture tube with three electron guns lying in one plane and a convergence pot common to all three electron beams, with an or several effects on the electron beams and on certain values from the outside magnetizable permanent magnets arranged in the neck of the color picture tube, through their Fields the beams of the three electron guns individually and essentially independently can be adjusted from each other, characterized in that two U-shaped Permanent magnets (3, 4 and 6,7) in the horizontal axis connecting the three electron beams (5) and in the vertical axis (8) passing through the central beam in a perpendicular attached to the plane standing in the middle of the electron beam in the convergence pot are. 2) Device according to claim 1, characterized datlurch that the distance the legs of the two U-shaped permanent magnets lying in the vertical axis (6,7) is chosen so that all three electron beams have the same magnetic Forces act.