FI57332C - MAGNETIC ANCORDER FOR ADJUSTMENT OF STATIONARY POSITION TO ETHER EQUIPMENT - Google Patents

Description

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Wa W (11) utlAqgninqsskrift 573 32 ζδτΐ? ^ Patent, 'ri.lelut ^ τ ^ (51) Kv.ik.' / Int.a. · H 04 · H 9/28 FINLAND —FINLAND (21) 13/13 (22) Hak «ml« ptlvft - Aittöknlnpdtf 0U.01.T3 ^ ^ (23) Starting line — CUtlghcttd ·! 0U. 01.73 (41) Interpreters julklMlui- Blivlt offantHc 13.07-73

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Patent- och ragisterstyralsan Anekin utUgd ochutUkrUtw pubUurad iL.uj.ou (32) (33) (31) Rockefeller Plaza, New York, NY 10022, USA (72) Robert Lloyd Barbin, Lancaster, Pennsylvania, USA (7U) Oy Kolster Ab (5U) Magnetic arrangement for adjusting the position of rays in a color television tube - Magnetic anordning för justering av strälpositionen i ett färgtelevi sionsrör This the invention relates to a magnetic arrangement for adjusting the position of rays in a three-beam color television tube having a cylindrical neck surrounding three in-line beams, the middle of which substantially coincides with the longitudinal axis of the neck and both outer beams are substantially symmetrically on opposite sides of said axis; located along the neck of the picture tube concentric with the axis of the picture tube.

In a three-beam color picture tube using an in-line arrangement (straight electron beam guns), the electron beam sources are directed to provide beam paths whose axes are substantially in a common plane, with the center beam path aligned with the tube neck axis and the outer beam paths aligned symmetrically sides.

For proper image reproduction, it is desirable that the three rays hit uniform areas on the phosphor surface of the picture tube. Although the electron-gun structures of the picture tube are ideally designed to provide such convergence of rays to the center of the image surface in the absence of beam deflection, the practical manufacturing tolerances of the picture tube and related components require the picture tube to be equipped with

Adjustable magnetic fields are commonly used to provide the necessary static convergence arrangement, and a typical commercially used arrangement, in both row and triangular cannon form, has involved the use of adjustable magnets associated with field-directing pole piece structures outside and inside the picture tube neck. The presence of magnetic pole piece structures for convergence purposes in the immediate vicinity of the neck region surrounded by the deflection coil unit brings with it a dilemma which implies an undesired interaction between the fields associated with the structures in question. s

The present invention thus relates to an adjustable magnetic arrangement which promotes the achievement of static convergence of in-line rays without the use of internal field-directing pole piece structures. In accordance with the principles of the present invention, it is provided to provide adjustable magnetic fields of two different characteristics to axially spaced areas of the tube neck, the nature of the second field being such as to intersect the respective outer radii while having an insignificant magnitude in the vicinity of the central radius. the nature of the second field is such that it intersects in parallel the relevant outer radii while also having an insignificant magnitude in the vicinity of the middle radius. By appropriately setting the orientation, polarity, and magnitude of the respective fields, with the opposite direction shifting the positions of the outer rays and / or the parallelism shifting the positions of the outer rays, the outer rays can be aligned with the center beam in the center of the image surface, if desired.

The present invention is thus characterized in that said system has a first multipole magnetic field generating portion adapted to provide a quadrupole field pattern to cause mutually opposite displacements of said outer beams in two opposite directions. a six-pole field pattern to cause parallel displacements of the outer beams in said area without substantially disturbing the middle beam path. Adjustably placed permanent magnet (PM) structures and adjustable energy electromagnetic (EM) structures are both possible for the implementation of four-pole and six-pole magnet systems.

A typical permanent magnet arrangement has a pair of juxtaposed four-pole magnetic rings and a pair of juxtaposed six-pole magnet rings rotatably mounted axially spaced on areas of the ring at the ring neck (which is free of internal magnetizable structures). alternating in polarity; i. compared to the given position of the north pole on the ring, the other poles are located S-90 °; N-I8O0; S-2700. Each comb six-pole ring has six symmetrically arranged hubs on the circumference of the ring with alternating polarities; rings relative to a given north pole position on the ring, the other pole positions are t S-60 °; N-120; S-180; N-240 °; and S-3000 · Combined rotation of a pair of rings changes the direction of the radius displacements while different rotation of the rings of the pair changes the magnitude of the radius displacement.

Using the FM arrangement described above, an additional pair of rotatable magnetic rings, bipolar in shape, can be conveniently supported on a common mounting portion with other pairs of rings, providing the additional ring pair with the property of jointly moving all three beams for conventional cleanliness correcting purposes. Or the exact positions of the respective pairs of rings on the axis of the tube neck behind the deflection coil unit do not appear to be critical, the order of position with hexagonal rings in the middle, four-pole rings in front and bipolar rings at the rear seems advantageous to easily achieve sufficient layout sensitivity for all other fields; rankings found to be possible.

It is desirable that in the FM magnetic arrangement described above, the implementation of the desired four-pole and six-pole magnetic systems be performed using a low permeability magnetic material (such as barium ferrite) in order to minimize interference or other interaction with the deflection coil unit. This may be particularly important in a designed embodiment of the present invention where the design of the color picture tube and associated deflection coil unit is such that substantially maintaining (i.e., within tolerances tolerated by the average viewer) the center of convergence conditions of the image surface throughout the raster sweep. The described arrangements of the present invention are particularly suitable for applications by providing means for easily achieving accurate convergence of the center of the image surface with structures that have little or no effect on the deflection field and in turn cause little or no interference in generating accurate deflection fields suitable for maintaining convergence.

In the above-mentioned embodiment of the present invention, the arrangement of bipolar, hexagonal and quadrupole magnetic ring pairs forms the only 57332 tube neck components (excluding the deflection coil unit) required for the construction and operation of a color picture tube *

It is an object of the present invention to provide a new magnetic arrangement for positioning beam positions in multi-beam cathode ray tubes *

Other objects and advantages of the present invention will be readily apparent to those skilled in the art from the following detailed description and accompanying drawings.

Figure 1 shows a side view of a color bar assembly comprising a permanent magnet type beam positioning apparatus formed in accordance with one embodiment of the present invention *

Fig. 2 shows a section along the line 2-2 in Fig. Lt so simplified that the structure inside the neck of the picture tube is not shown.

Figure 3 is an exploded perspective view of a plurality of magnetic ring elements in the beam alignment apparatus of Figure 1 *;

Figures 4a, 4h and 4o are diagrams illustrating possible different directions of beam position transfers at different Kieft room positions of the four-pole magnetic ring elements in the apparatus of Figure 1.

Figures 5 * »5b and 45c are diagrams illustrating different directions of radial position transfer at different rotational positions of the six-pole magnetic ring elements of the apparatus of Figure 1.

Figures 6a, 6b and 6c are diagrams illustrating the different directions achievable in radial position displacements at different rotational positions of the bipolar magnetic ring elements of the apparatus of Figure 1 *

Figures 7a and 7b are diagrams illustrating how the differential rotation of the four-pole magnetic ring elements from their positions shown in Figure 4a affects the magnitude of the beam displacement.

Figs. 8a and 8b are diagrams illustrating four-pole electromagnetic structures that can be used in the electromagnetic transducer 88a of the embodiment 8 of Fig. 1 of the present invention.

The side view of Fig. 1 shows a color image tube 20 with three radii and a perforated plate in a row, with a cylindrical neck portion 21 at the base side and a funnel portion 23 at the viewing end, with its outer neck components assembled therein. The latter include a deflection coil assembly 27 (not shown) surrounding the front end of the neck 21 of the picture tube and the associated widening portion of the funnel portion 23.

Behind the deflection coil unit 27 are other neck components, six rotatable magnetic rings 30A, 30B, 40A, 40B, 50A and 50B mounted on a common (non-magnetic) support member 70 surrounding the neck 21. As better seen in the cross-sectional view 50 of Figure 2 illustrating the front ring 50

5 57332, two protruding strips (e.g., 51B, 52B) are formed in each ring to facilitate manual rotation of the ring by the support member 70. Details of the internal structure of the tube neck are not shown in the cross-sectional view of Figure 2 for simplification, but the positions of the axes I and III are nominal. shown inside the neck of the tube to indicate the in-line shape of the paths of the beams) the axis II of the middle beam is depicted substantially coincident with the axis of the neck of the tube. The interior surrounded by the magnetic rings of the tube neck 21 is free of magnetic pole pieces or other magnetizable structures.

The inner diameter of the support member 70 is large enough to allow the support member to slide over the neck 21 of the tube. The tensioning strip 80 provides a means for securing the support member 70 in the desired fixed position on the neck 21. Axially spaced (non-magnetic) drive rings 60 suitably attached to the support member 70 form three suitably spaced lengths of the support member 70 for the respective rotatable ring pairs 30A. 30B) 40A 40B; and 50A 50B) for placement. Thin spacers (not shown) of a suitable material (e.g. paper) may be placed between the rings of each pair to facilitate their independent rotation.

In the simplified fragmentary view shown in Figure 3, only the magnetic rings (minus their strips) are shown to show the magnetization method associated with each ring. Each ring of the narrowest pair 30A, 30B has a bipolar magnetization mode in which the position of the north pole is diametrically opposite the position of the south pole. Each ring of the middle pair of rings 40A, 40B has a hexagonal magnetization mode in which the poles are evenly spaced (60 ° apart) on the circumference of the ring with alternating polarity. Both rings 50A and 50B of the front pair have a four-pole magnetization mode in which poles of alternating polarity are evenly spaced (90 ° apart) on the circumference of the ring.

The diagram of Figure 4 illustrates the nature of the radial position displacements caused by the fields of a pair of four-pole rings (50A, 50B) with a certain orientation thereof. In the orientation of Figure 4a, the ring 50A is positioned so that its north poles are located directly above and below the axial beam position II) the ring 50B is not positioned in the same way (whereby the fields of the two rings are parallel and completely complementary). With the described orientation, the field in the beam position I is oriented horizontally with such polarities as to cause the electron beam of the beam position I to move downwards (with the movement of the electrons in the plane of the paper in Figs. 4a, etc.). The field beam mass III is also horizontally oriented but of opposite polarity, 6,57332, causing the electron beam of position III to move upwards.

In the orientation of Figure 4b, the rings 50A and 50B are both rotated 45 ° counterclockwise from their positions illustrated in Figure 4a. In the positions of Figure 4b, the direction of the field in the beam position I is vertically downwards while the field in the beam position III is vertically upwards; the resulting radial position displacements are horizontally right at position I and horizontally left at position III. Figure 4c illustrates that rotating both rings further counterclockwise (approximately 22.5 °) results in opposite oblique displacements of the beam positions (up and to the right in position I and down and to the left in position lii). It should be noted that no beam position transfer is depicted anywhere in Figure 4a, 4b or 4c for the electron beam in axial position II. This is because the center of the aperture of the quadrupole rings is substantially fieldless, as a result of which the radius in the axial position II is not substantially affected by the quadrupole rings regardless of their orientation. The four-pole field formed by the rings 50A and 50B thus allows equal or opposite displacements of the outer rays from the three in-line rays in any direction without interfering with the central axial beam (which can thus serve as a reference beam for the desired point alignment on the picture tube image surface).

The diagrams shown in Figure 5 illustrate the nature of the displacements of the beam stations resulting from the fields of the six-pole ring pair (40A, 40B) with a certain orientation thereof. In the orientation shown in Fig. 5a, the ring 40A is located so that the two opposite poles are located in a horizontal diameter and in the same line as the row stations I, II and III in a row, with the north pole of the pair adjacent to station I; the ring 40B is similarly positioned. In the described orientation, the direction of the field at position I is horizontal and of such polarity as to cause the electron port of position I to move upwards; the direction of the field at position III is also horizontal and of the same polarity, in this case causing the electron beam of position III to move upwards. Fig. 5b illustrates the case where the rings 40A and 40B are rotated 50 ° counterclockwise from the position of Fig. 5a, resulting in a horizontal shift to the left at both radial positions I and III. Figure 5c illustrates that a smaller counterclockwise rotation (15 °) causes a similar oblique displacement at positions I and III.

As in the case of the four-pole ring described above, no transfer to the radius in the axial position II has been shown in this case as well, and again the reason is that the central area of the openings of the six-pole rings is substantially fieldless. The hexagonal field formed by the rings 40A and 40B thus makes it possible to achieve in any desired direction 7 57332 a simultaneous and simultaneous transmission to the outer rays of the three rows in a row without disturbing the middle, reference beam.

Contrary to what was explained above for four-pole and six-pole rings, bipolar rings 30A and 30B have an effect on all three radii. This is illustrated in Figure 6a, where the common horizontal displacement of all three radii results from the vertical orientation of the poles of the bipolar rings, Figure 6bf where the common vertical displacement of all three radii results from the horizontal orientation of the poles of the bipolar rings, and Figure 6c, where the common oblique displacement of all three radii results. oblique orientation of bipolar tires.

With the indicated common displacement at all three radii, the bipolar field provided by the bipolar rings 30A and 30B makes it possible to set the angle of incidence of the three beams on the picture tube perforated plate to ensure that each beam hits the appropriate phosphor range (i.e., optimum purity).

In all Figures 4, 5 and 6, the same location of the pair of rings is assumed. Such a location provides the maximum magnitude for the relevant beam displacements. Figures 7a and 7b illustrate how the relative rotation of the rings of a pair relative to each other away from direct alignment causes a reduction in the beam transfer effects associated with the pair. To illuminate this, quadrupole rings 50A and 50B have been selected. In Fig. 7 &, the quadrupole ring 50A is rotated 15 ° clockwise from the position of Fig. 4a while the quadrupole ring 50B is rotated 15 ° counterclockwise from the position of Fig. 4a. As shown by the directions and lengths of the arrows in Fig. 7 *, the directions of the radial displacements at positions I and III are the same as in Fig. 4a, but the magnitudes of the displacements of both radii are reduced. This size-reducing effect, jokfc-related to the "disintegration" of a pair of magnetic rings, is familiar to those familiar with the use of previously known purity ring pairs or interrupt ring pairs, and * need no further explanation here.

Or, as permanent magnet structures have been described above to form the desired field shapes, it should be noted that such field shapes can also be produced by electromagnetic structures. Figures 8a and 8b illustrate a pair of four-prong electromagnet structures 50A 'and 50B1, each of which has four coils symmetrically arranged so that adjacent coils (coils) are wound in opposite directions. The ring 50A 'illustrated in Figure 8a is fixedly mounted so that its poles have the orientation of Figure 4a to provide opposite vertical displacements to the radii I and III. The ring 50B * illustrated in Fig. 8b is fixedly positioned so that the ringing poles have the orientation described in Fig. Β 57332 ea 4b to provide opposite horizontal displacements to beam positions I and III * By setting the polarity and magnitude of the current in the coils of the respective rings 90 100 by arranging the taps), any of the effects obtained by rotating the permanent magnet rings 50A and 50B can be repeated. It is observed that a comparable technique can be used in hexagonal electromagnetic rings to simulate the rotation of permanent magnet rings 40A and 40B *

As previously explained above, the order of the bipolar, hexapodine, and quadrupole fields in question is advantageous because it places the hexagonal field in the center to maximize its efficiency. It can also be seen that there is a uniform preferred field layout arrangement to minimize correction requirements. * It is preferred that the bipolar field be set first to optimize purity, thereby providing a reference beam position. A six-pole field is then set to provide the necessary common displacements of the outer rays with respect to the axial radius. * Finally, a four-pole field is set to provide the opposite displacements of the outer rays necessary to achieve final alignment. This layout order (in order along the radius path) has the advantage that a particular field layout did not change the position of the radii in the area of the previously set field.

A low permeability material, such as barium ferrite, can be used to form the various magnetic rings depicted in Figure 1 to minimize the undesired interaction between the deflection field and the convergence and purity fields. However, with the described sequence of ring pairs placing the purity rings JOA and JOB away from the deflection coil 27, this precaution may be omitted in the case of a purer purifier, such as a suitable steel, to be used on the purity rings JOA and JOB with only minor adverse consequences.

It should be noted that in practice there may be conditions where no four-pole and / or six-pole field correction is required. The transfer effect of any pair of rings can be reduced or the transfer effect can be eliminated by placing the rings of the pair in a position that cancels the effect of each other, as exemplified in Figure 7b.

Claims (5)

57332 A magnetic arrangement for adjusting the position of rays in a three-beam color television tube (20) having a cylindrical neck (21) surrounding three in-line beams (I, XI, III), the middle of which substantially coincides with the longitudinal axis of the neck and both outer beams are substantially symmetrically on opposite sides of said axis, the arrangement comprising a magnetic field generating system (30, 40, 50) located along the neck of the picture tube concentrically with the axis of the picture tube, characterized in that said system has a first multipole magnetic field generating part (50A, 50B) which is adapted to provide a four-pole field pattern to cause mutually opposite displacements of said outer beams (I, III) in my two opposite directions without substantially disturbing the middle beam path, and at least a second multipole magnetic field generating portion (^ 0A, UOB) adapted to provide six a pressure field pattern to cause parallel displacements of the outer radii in said region without substantially disturbing the central radius path. An arrangement according to claim 1, characterized in that said quadrupole field pattern generating part comprises a pair of quadrupole magnetic rings (50A, 50B) surrounding a part of said region; and said hexagonal field shape generating portion includes a pair of hexagonal magnetic rings (UOA, 40B) surrounding the second portion of said region and axially spaced from said region. Arrangement according to Claim 2, characterized in that the magnetic rings are individually rotatable permanent magnetic rings. An arrangement according to claim 2 or 3, characterized by a cylindrical support member (60) surrounding the neck (21) of the picture tube and a pair of bipolar magnetic rings (30A, 30B) each magnetized across the diameter of the ring to extend the same row in said four-pole magnetic ring. the poles of alternating polarity in each ring are located 90 ° on the circumference of the ring, that in said pair of six-pole magnetic rings (UOA, 4θΒ) the poles of alternating polarity in each ring are located at 60 ° on the circumference of the ring, and that said pairs of rings are rotatably mounted around longitudinally spaced points. An arrangement according to claim k, characterized in that the deflection coil unit (27) is mounted on the neck, the quadrupole magnetic rings (50A, 50B) are mounted on a support member adjacent the deflection coil unit, the bipolar magnetic rings (30A, 30B) are mounted on the support member further from and that the six-pole magnetic rings (UOA, UOB) are mounted on the support member at a point between the bipolar magnetic rings and the quadrupole magnetic rings.