KR800000927B1 - Convergence apparatus for in-line beams - Google Patents

Abstract

A first magnetic field producing member has it poles oriented for producing an initial predetermined movement of the two outside ones of three in-line beams of a cathod ray tube. The second and third field producing members are adjustable for producing variable strength and direction of magnetic fields for moving the two outside beams in opposite and the same directions, respectively, for converging the three beams.

Description

In-line beam convergence device

1 is a partial schematic plan view of a display system comprising a cathode ray tube and a non-convergence device according to the present invention;

2 is an exploded view of the beam convergence of FIG.

3-10 illustrate the beam convergence action of various members of the first and second beam convergence devices.

The present invention relates to an apparatus for converging three inline beams of a cathode ray tube.

Color display systems, such as those used in color television receivers, contain cathode ray tubes in which three electron beams are modulated by a color representative video signal. The beams impinge on the color fluorescence region on the inside of the tube image screen to reproduce the color image when the beams are deflected to scan the raster. In order to reproduce color images nicely, the three beams must be actually converged on the screen at every point on the laminator. The beams can be converged at points away from the center of the raster using a dynamic convergence device or magnetic converging technique or a combination of both. Although a device may be used to achieve convergence when the beam is deflected, there must be some provision to statically converge the unbiased beam at the center of the screen. Static convergence devices are essential because the tolerances in manufacturing the assembly of the electron beam gun assemblies and the tank gun into the neck of the imaging tube often result in a static misconvergence state.

U.S. Patent Nos. 3,725,831 and 3,808,570 describe a static convergence assembly for use with cathode ray tubes producing three inline beams. The assembly provides four-pole and six-pole magnetic fields for moving the outer two beams in opposite and same directions, respectively, with no effect on the central beam. The intensity of the generated magnetic field and the direction of beam movement are determined by rotating the pair of 4-pole members, respectively, around the neck of the cathode ray tube in the same direction relative to each other in the same movement as the pair of 6-pole wide members with equally spaced poles. Controlled.

The device can satisfactorily and statically converge the three inline beams of a color television image tube. However, despite having polarities of several magnetic elements positioned to generate a magnetic field force in a predetermined direction when mounted on the neck of the tube, as described above, the first observed beam landing pattern from one tube to another tube can be Variation prevents the operator from taking effective steps to statically converge the beams. This composition problem occurs whether the magnetic members are manually controlled or mechanically controlled by the motor drive gears that engage the gear teeth on the members. The motor is controlled by appropriate switches that the operator can control. The problem is prominent when the beams are very light misconverged because they can produce a very large misconvergence of the members even in the wrong direction. Eventually, manufacturing costs can be increased because of relatively long adjustment times, sub-optimal convergence conditions, or both.

The convergence device for the three inline beams at the tip of the cathode according to one embodiment of the present invention includes a first magnetic field generating member positioned to move two of the three beams outside of the first predetermined beam. The second and third magnetic field generating members can be adjusted to generate a variable strength and directional magnetic field for moving the two outer beams in opposite or identical directions, respectively, to converge the three beams.

In FIG. 1, a color television receiving tube is not shown but includes a glass seal 11 having a front surface of the screen having a colored fluorescent region on its inner surface. Slightly isolated from the rear of screen 12 on the inside of the tube is shadow mask 13 which includes a number of openings through which three electron beams impinge on the color fluorescence. Around the neck of Enclosure 11, there is an appropriate deflection yoke 14 that allows three electron beams to be scanned on the screen when energized. Electron gun 16 placed in the neck of the tube generates three horizontal inline beams, green and blue. Placed above the electron gun area around the neck of enclosure 11 are static convergence and purity devices 15.

In FIG. 2 a static convergence and purity device 15 is shown having a through-cylindrical member 17 suitable to fit over the neck of the water pipe as shown in FIG. At one end of the member 17 is an outwardly extending shoulder 18 and at the other end is a penetrating portion 19 and a plurality of individual fingers 20. Ring member 21 fits snugly over member 17 and is indexed appropriately to prevent the first member from rotating around member 17 when assembled.

A thin washer 22 of suitable material, such as paper, separates the pair of four-pole magnetic ring members 23 and 24 from the member 21. The quadrupole ring members 23 and 24 can be rotated around the member 17. Another washer 22 separates the six-pole magnet ring members 25 and 26 from the four-pole member 24. Ring members 25 and 26 can also be adjusted by rotating around member 17. Another washer 22 separates the first purity ring magnet 27 from the member 26 and then separates it from the second purity ring magnet 28 by another washer 22. The locking joint 29 fits into the cylindrical member 17 and engages with the thread 18 to lock the rotatable magnetic members in place when they are properly adjusted. The clamp 30 is then assembled around the fingers 20 to clamp the cylindrical member 17 firmly to the neck of the glass seal 11 of the water pipe. Each ring member 23, 24, 25, 26, 27 and 28 has at least one protruding tab 30 to facilitate rotation of the respective rings.

With the exception of the stationary 4 and 6 pole ring members 21, the remainder of the static convergence and purity assembly is similar to the assemblies described in the aforementioned patent. The ring members 23 and 24 have a pair of southern magnetic poles separated by 90 ° oppositely from the oppositely opposite northern magnetic poles. Rotation of the 4-pole ring members 23 and 24 with respect to each other changes the strength of the 4-pole mother-of-pearl, rotation of the ring members 23 and 24 changes the strength of the 4-pole field, and rotation of the ring members 23 and 24 causes the neck of the sealing 11 Change the direction of the 4-pole magnetic field together to moderately affect the beams in the part. Ring members 23 and 24 move two of the three in-line beams in opposite directions without actually giving effect to the central beam.

The ring members 25 and 26 are each isotropically isolated from each other by 60 ° including three arctic poles and three antarctic poles, respectively. The ring members 25 and 26 are rotated relative to each other to control the strength of the six-pole mother tongue and the ring members 25 and 26 are rotated together around the neck of the tube to control the direction of the six-pole magnetic field in the neck of the water pipe. This six-pole magnetic field moves two out of three inline beams in the same direction without actually affecting the center beam.

Purity ring magnets 27 and 28 are of the conventional type, each having a pair of oppositely opposite arctic south poles. Rotating the purity rings 27 and 28 will move all three inline beams in the same direction.

FIG. 3 shows a view from the screen of the water tube into the neck of glass enclosure 11 which includes an electron gun that produces three horizontal inline beams blue, green and red positioned successively as shown for the horizontal and vertical axes X and Y. Cross-section.

4 illustrates the converging of the beams on the screen where the blue and red outer beams are converging on the central green beam. Ideally this is the state of the beams produced by the ideal electron gun fully mounted in the tube. As a practical matter as described above, this state cannot be realized in the absence of static convergence forces. As a practical matter as described above, this state cannot be realized in the absence of static convergence forces. The representative misconvergence state of the beam at the center of the screen may be as illustrated in FIG. In FIG. 5, the green beam is shown at the center of the screen, the red beam is at the upper right and the blue beam is at the lower left to some extent. It should be noted that representative misconvergence patterns in the center of the screen may be an array of misconverged beams before the appearance of true convergence. As mentioned above, the operator performing the positive convergence correction does not know how to adjust the 4-pole and 6-pole adjustable magnetic ring members.

6 and 7 illustrate the effect on the beams by the first non-rotating magnetic ring member device 21a and 21b. FIG. 6 shows the magnetic ring member 21a with the north and south poles positioned about 45 ° from the vertical and horizontal deflection axes as viewed from the screen of the water pipe. The effect of this four-pole magnetic field is to move the lateral lateral beams in opposite directions by a predetermined amount that is larger than the misconvergence of the beams shown in FIG. By shifting the right adjustment method to determine the forces acting on the beams, it can be determined that the four member 21b positions the beams as described in FIG. 6 from the starting position as described in FIG. It is important that the 4-pole magnetic field causes the blue and red beams to overlap in the horizontal direction.

7 shows the effect of the six-pole magnetic field produced by the non-rotating six-pole ring member 21 with its poles positioned as described for the deflection axis. By adjusting to the right, the effect of the six-pole magnetic field can again be determined by moving the red and blue beams in the same direction to the right relative to the green beams as illustrated by the differences between the beam positions within the sixth and seventh degrees. The strength of the 4 and 6 poles produced by the magnetic members 21a and 21b shifts the red and blue beams and their beams in a horizontal crossover state, even if there is the first misconverged beam landing type in FIG. It is chosen to be large enough to allow. Thus, ring members 21a and 21b always result in a predetermined offset in the direction of the red and blue beams as generally described in FIG.

Although the effects of the 4 and 6 pole stationary magnetic field are shown separately in FIGS. 6 and 7, the magnetic ring members 21a and 21b are illustrated by member 21 in FIG. 2 and are made of a magnetic material such as barium ferrite and quadrupole And a single member magnetized as a six-pole combined magnetic field.

For the beams in the position illustrated in FIG. 7, positive convergence adjustment is now made by the device according to the aforementioned patent. 8 illustrates two overlapping quadrupole magnetic ring members 23 and 24. Members 23 and 24 are initially positioned to rotate relative to each other as illustrated by the polar device in the point source. Such overlap of the north and south poles of the two rings results in a cancellation of the quadrupole field. From this position the magnetic rings are rotated in the opposite direction as indicated by the arrows near the tab members 30 of each ring to produce a magnetic pole arrangement illustrated by the north and south pole marks not enclosed in the circle of FIG. This device increases the intensity of the 4-pole magnetic field by moving the red and blue beams from the position they occupy in FIG. 7 to the position illustrated in FIG.

It is important that this intensity adjustment of the 4-pole mother tongue with polarities positioned as indicated in FIG. 8 is provided for the horizontal convergence of the red and blue beams.

The next step in the constant convergence adjustment is to simultaneously rotate the two four-pole ring members 23 and 24 in the same direction from the position occupied in FIG. For the particular beam form shown in FIG. 8, the counterclockwise rotation of the rings 23 and 24 is made through the same angle as half of the angle between the points a and c in FIG. . The effect of this rotation of the two rings is to move the red beam from point a to arc a 'and the blue beam from point c to arc c'. Points a and c in FIG. 8 coincide with the positions of the red and blue beams, respectively, as illustrated in FIG. As the red and blue beams move along their respective arcs, the red and blue beams converge at the point where the arcs a 'and c' meet each other. Thus the red and blue beams are converged as illustrated in FIG.

The next step is to move the ring member 25 in a manner similar to that described for the 4-pole magnetic field if desired to move the red and blue beams converged in the same direction as indicated by the arrows in FIG. This is for changing the strength and direction of the six-pole magnetic field generated by 26. As a result, as shown in FIG. 4, the three beams are brought into a converging state. Although not illustrated, the starting positions for the two six-pole rings 25 and 26 were similar to those shown for the eighth-pole four-pole rings with one ring's north poles superimposed on the other south poles so that no initial six-pole magnetic field existed. . For reference, the overlapping polarities are located with the two upper polarities separated 30 ° from the Y axis. For red and blue beams positioned as illustrated in FIG. 10, the two six-pole ring members 25 and 26 are then in opposite directions to each other until their polarities are in the position as indicated in FIG. Is rotated. This provides the necessary direction of the six-pole field to move the red and blue convolved beams as indicated in FIG. 10 by the arrows to converge on the green beam. Only when horizontal movement is required do the two six-pole rings need to be rotated simultaneously with the beam shape illustrated in FIG.

In the illustrated examples, the rotation of the 4-pole and 6-pole magnet rings 23-26 results in a magnetic field of maximum strength to simplify many of the individual polarities illustrated in the figures. In practical use, it is necessary to move each 4-pole or 6-pole ring pair from the magnetic field canceling position only in a partial direction toward a sufficient magnetic field strength position.

By using the invention described above, the magnet rings can be moved by hand by the illustrated tabs and they can be moved by another suitable device or mechanically as described above. In all cases, the advantages of the present invention can be appreciated. because. The operator must detect the proper direction to move the rings, but even if there is any initial misconvergence pattern, the predetermined set of beams caused by the magnetic fields generated by the fixed 4-pole and 6-pole magnet members 21 This is because the position can be preceded by the original orientation position as illustrated by the belief that the beam is moved in the proper direction to affect its convergence.

Claims (1)

As described herein and shown in the figures, the first device, the two outer beams, may be used to generate a magnetic field for moving two outer beams of the beams in a predetermined direction relative to the center beam of the three beams. A second device for generating a magnetic field suitable for converging, and a third device for generating an adjustable magnetic field for converging said two converged outer beams on said central beam. A beam convergence device for converging three inline electron beams.

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