US3609607A - Lateral magnet assemblies - Google Patents

Abstract

A lateral magnetic assembly adapted to be mounted on the neck of a color cathode-ray tube to adjust color electron beams is comprised by a first magnetic member having three equally spacedapart radial projections, a second magnetic member having two radial projections each interposed between adjacent radial projections of the first magnetic members, inner ends of all radial projections terminating on a circle, a permanent magnet and clamping members formed on the first and second magnetic members to rotatably support the permanent magnet.

Description

United States. Patent [72] Inventor Takeyoshi Sohma Funabashi, Japan [2]] Appl. No 41,470 [22] Filed ,May 28, 1970 [45] Patented Sept. 28, 1971 Denki Onkyo Company, Limited Nishirokuzo, Ohota-ku, Tokyo, Japan [73] Assignee [54] LATERAL MAGNET ASSEMBLIES 3 Claims, 3 Drawing Figs. [52] US. Cl 335/212, t 313/77 [51] lnt.Cl H01! 1/00 [50] Field of Search 335/212; 313/76; 1/77 [56] References Cited UNITED STATES PATENTS 2,813,212 ll/l957 Grundmann FOREIGN PATENTS 208,818 3/1956 Australia Primary ExaminerJ. V. Truhe Attorney-Chittick, Pfund, Birch, Samuels & Gauthier ABSTRACT: A lateral magnetic assembly adapted to be mounted on the neck of a color cathode-ray tube to adjust color electron beams is comprised by a first magnetic member having three equally spaced-apart radial projections, a second magnetic member having two radial projections each interposed between adjacent radial projections of the first magnetic members, inner ends of all radial projections terminating on a circle, a permanent magnet and clamping members formed on the first and second magnetic members to rotatably support the permanent magnet.

PATENTED SEP28 I9?! FIG. 2

FIG.

FIG. 3

TAKEYOSHI SOHMA INVENTOR BY W H MQM BACKGROUND OF THE INVENTION This invention relates to improvements of a lateral magnet assembly adapted to be mounted on a three-beam-type color cathode ray tube.

As is well known in the art in the three-beam-type color cathode-ray tube, one of three electron beams, particularly a blue beam is required to be adjusted in the lateral direction (horizontal direction) with respect to red and green beams. The lateral magnet assembly is utilized to attain this object. Among various types of lateral magnet assemblies, a lateral magnet assembly utilizing six-pole magnets was found most suitable. The lateral magnet assembly utilizing six-pole magnets comprises two magnets each having alternate N and S poles at positions corresponding to apices of a regular hexagon, said magnets being made of annular magnetic members rotatably mounted like a centering magnet assembly. When such a lateral magnet assembly including six-pole magnets is used the red beam and green beam can be shifted a little in opposite directions by the lateral movement of the blue beam. This is extremely advantageousfor the adjustment of color television tubes.

However, since the six-pole magnet is difficult to magnetize with equal intensity accurate areas of the ring shaped mag netic member, or to provide accurate symmetrical magnetization it is difficult to manufacture it. For this reason, the lateral magnet assembly is extremely expensive. Further, in order to attain the desired object over a long period it is necessary to mount the center of the six-pole magnets of the lateral magnet assembly at a position somewhat displaced from the center of the neck of the cathode-ray tube so that assembling of the lateral magnet assembly is troublesome. Further in order to shift blue, red and green beams only in the lateral direction it is necessary to rotate two six-pole magnets by means of gears and the like thus complicating the construction.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide an improved lateral magnet assembly which is simple in construction and can be readily mounted on the neck of a color cathode-ray tube.

Another object of this invention is to provide a novel lateral magnet assembly for color cathode-ray tube capable of moving a blue electron beam in one lateral direction and green and red electron beams in the opposite direction by a single operation.

Briefly stated, in accordance with this invention there is provided a lateral magnet assembly for use in a color cathoderay tube, comprising a first magnetic member having three equally spaced apart radial projections acting as magnetic poles, the inner ends thereof terminating on a circle, a second magnetic member having two radial projections, each inter posed between adjacent radial projections of the first magnetic member, the inner ends of the projections of the second magnetic member also terminating on a circle, a permanent magnet having diametrically opposite N and S poles, and magnetic clamping members formed on the first and second magnetic members to rotatably support the magnet.

BRIEF DESCRIPTION OF THE DRAWING The invention can be more fully understood from the following description when taken in conjunction with the accompanying drawing in which:

FIG. 1 shows a front elevation of a lateral magnet assembly embodying this invention and mounted on the neck of a color cathode-ray tube;

FIG. 2 shows a side elevation of the lateral magnet assembly shown in FIG. I and FIG. 3 is a diagram to explain the operation of the novel assembly.

2 DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 and 2 showing the manner of mounting the novel lateral magnet assembly on the neck 10 of a color cathode-ray tube, blue, red and green electron beams are designated by reference letters B, R and G respectively. The lateral magnet assembly comprises a first magnetic member 11 of an annulus with one portion cut away and with three radial projections 11a, llb and at a substantially middle portion and at opposite ends. As shown in FIG. 2, the inner end of each projection is bent at right angles to extend in the axial direction of the cathode-ray tube. Bent portions of the projections 11a, llb and 11c are arranged on a circle having a center on the axis of the cathode-ray tube. The lateral magnetic member further comprises a second magnetic semicircular member 12 with radial projections at the opposite ends. The inner ends of these projections are also bent at right angles to extend in the axial direction of the cathoderay tube. These bent portions are also on a circle having a center on the axis of the cathode-ray tube. As best shown in FIG. 2 first and second magnetic members 11 and 12 are disposed in parallel and spaced apart a predetermined distance along the axis of the tube so that bent portions of projections 11a, llb, 11c and 12a, 12b of magnetic members 11 and 12 extend in the opposite direction, that projection 12a of the second magnetic member 12 is positioned between projections 11a and 11c of the first magnetic member 11 and that projection 12b of the second magnetic member 12 is positioned between projections 11b and 110 of the first magnetic member 11. At substantially the middle portions of magnetic members 11 and 12 are integrally formed clamping members 11A and 12A to rotatably support therebetween a cylindrical magnet 13 with diametrically opposite N and S poles. Clamping members 11A and 12A have integral fingers 14 to firmly hold magnet 13.

Although not shown in the drawing these first and second magnetic members are held in position by a suitable shoulder so as to be readily mounted on the neck of a cathode-ray tube.

When magnet 13 clamped between clamping members 11A and 12A is rotated to the position shown in FIG. 2 wherein N pole faces clamping member 12A and S pole clamping member 11A, projections 11a, llb and 110 of the first magnetic member 11 will act as S poles whereas projections 12a and 12b of the second magnetic member 12 as N poles. The field intensities of respective N and S poles are substantially the same. As diagrammatically shown in FIG. 3 the magnetic flux of respective poles acts upon blue, red and green electron beams B, R and G. More particularly blue electron beam B is acted upon by the flux between projection llc of the first magnetic member 11 and projections 12a and 12b of the second magnetic member 12, red electron beam R by the flux between projection 12b of the second magnetic member 12 and projection 11b of the first magnetic member 11, and green electron beam G by the flux between projection 12a of the second magnetic member 12 and projection 11a of the first magnetic member 11. Assuming that electron beams B, R and G travel from the rear side to the front side of the sheet of drawing then blue electron beam Bwill be subjected to a force acting to the left as viewed in FIG. 3 whereas red and green electron beams to substantially the equal force acting to the right. As can be clearly noted from FIG. 3, since the force acting upon blue electron beam B is larger than that acting upon red and green electron beams R and G, blue electron beam B is moved horizontally over larger distance. This action of the magnetic flux is substantially equal to that of a conventional lateral magnet assembly utilizing sixpole magnets. Consequently, when blue electron beam B is moved laterally, red and green electron beams R and G are moved in the opposite direction over the same small distance, as required.

In this manner, since in accordance with this invention, magnet 13 functions to magnetize respective projections Ila, 11b, 11c and 12b of the first and second magnetic members 11 and 12, respective projections will have the same field intensity. Moreover, rotation of magnet 13 results in uniform change in the field intensity of respective projections or magnetic poles and even upon reversal of the polarities thereof similar change of the field intensities can be obtained. In other words, it is possible to reverse the direction of the force acting upon respective electron beams. Thus, adjustment of color beams can be effected very easily. Moreover, irrespective of which one of two magnetic members is positioned closer to the face plate of the cathode-ray tube, the effects upon the beams are the same. Since it is not always necessary to coincide the axis of the cathode-ray tube with centers of respective projections 11a, 1 lb, llc and 12a, 12b of the first and second magnetic members 11 and 12 it is very easy to construct and mount the assembly. Although parallel arrangement of the first and second magnetic members 11 and 12 creates some amount of leakage flux, as the direction of the leakage flux is in parallel with the direction of travel of electron beams (in some case in the opposite direction), such leakage flux does not affect the electron beams.

While this invention has been shown and described in terms of a preferred embodiment it will be clear that the configurations of magnetic members, of the projections thereof acting as magnetic poles and of the clamping members are not limited to those illustrated. Projections may be disposed in such positions that to produce magnetic force to move laterally the blue electron beam and to move the red and green electron beams in the opposite direction over a small distance.

What is claimed is:

l. A lateral magnet assembly comprising a first magnetic member having three equally spaced-apart radial projections acting as magnetic poles, the inner ends of said projections terminating on a circle, a second magnetic member having two radial projections, each interposed between adjacent radial projections of said first magnetic member, the inner ends of the radial projections of said second magnetic member also terminating on a circle, a magnet having diametrically opposite N AND S poles, and magnetic clamping members formed on said first and second magnetic members to rotatably support said magnet.

2. The lateral magnet assembly according to claim 1 wherein said first and second magnetic members are disposed in parallel and are spaced apart along the axis of a cathode-ray tube on which said assembly is to be mounted.

3. The lateral magnet assembly according to claim 1 wherein the inner ends of said radial projections of said first and second magnetic members are bent substantially at right angles to extend in the direction of the axis of a cathode-ray tube on which said assembly is to be mounted.

Claims (3)

1. A lateral magnet assembly comprising a first magnetic member having three equally spaced-apart radial projections acting as magnetic poles, the inner ends of said projections terminating on a circle, a second magnetic member having two radial projections, each interposed between adjacent radial projections of said first magnetic member, the inner ends of the radial projections of said second magnetic member also terminating on a circle, a magnet having diametrically opposite N and S poles, and magnetic clamping members formed on said first and second magnetic members to rotatably support said magnet.

2. The lateral magnet assembly according to claim 1 wherein said first and second magnetic members are disposed in parallel and are spaced apart along the axis of a cathode-ray tube on which said assembly is to be mounted.

3. The lateral magnet assembly according to claim 1 wherein the inner ends of said radial projections of said first and second magnetic members are bent substantially at right angles to extend in the direction of the axis of a cathode-ray tube on which said assembly is to be mounted.

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