US3516038A - Convergence device - Google Patents

Description

June 2, 1970 HIRONORI HISAMOTO ETAL CONVERGENCE DEVICE Filed May 20, 1968 INVENTORE flironarl fll'samatv Mane a Nl'slr 'mar' Kan)! maahida 1') p BY @ifimli ATTORNEYS United States Patent 3,516,038 CONVERGENCE DEVICE Hironori Hisamoto and Muneo Nishimura, Hirakata-shi, and Kanji Machida, Moriguchi-shi, Japan, assignors to Matsushita Electric Industrial Co., Ltd., Osaka, Japan, a corporation of Japan Filed May 20, 1968, Ser. No. 730,291 Claims priority, application Japan, May 22, 1967, 42/ 43,777, 42/ 43,778 Int. Cl. H011? 7/00 U.S. Cl. 335-212 1 Claim ABSTRACT OF THE DISCLOSURE A frame constituting the convergence device is provided with a large-diameter portion, a recess is formed in said large-diameter portion, and a disk-like blue-lateral convergence magnet is supported in said recess so that the adjustment of blue-lateral convergence can be satisfactorily effected by the rotation of said magnet.

BACKGROUND OF THE INVENTION This invention relates to a convergence device for use with a color television receiver, and more particularly it pertains to such device in which a blue-lateral convergence magnet can be mounted easily, thereby achieving convergence very easily and accurately.

In conventional convergence devices as shown in FIG. 7, a blue-lateral convergence magnet 20 configured in the form of a cylinder is supported by a U-shaped fitting 22 attached to a frame 21, and it is freely rotated through a thumb 23. With such a cylindrical blue-lateral convergence magnet 20, however, there has been a tendency that the magnetic poles are incorrectly positioned in the axial direction of the cylinder or enlarged. Furthermore, incorrectness of the position of the magnet 20 to the frame 21 tends to be superimposed upon incorrectness of the mangetization. Due to the fact that such a incorrectness is further increased by the fitting 22, there occurs such disadvantageous tendency that the blue beam is radially displaced although it should be laterally adjusted by means of the blue-lateral convergence magnet, and that an unwanted field causes deterioration in the beam focusing and has great adverse effect on the red and green beams. Even if such incorrectnesses are not taken into consideration, a complex magnetic field is established by a magnetic flux emanating from the ends of the magnet because of the cylindrical configuration of the magnet 20. This constitutes such an inconvenience that the function of lateral adjustment cannot be achieved by the geomet rically linear deflection of the electron beams so that there tends to occur unbalanced interference with respect to the red and blue beams, thus requiring a complex color adjustment.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of this invention to eliminate the foregoing conventional drawbacks.

Another object of this invention is to provide a convergence device in which a recess for accommodating a blue-lateral convergence magnet is formed in the frame itself to greatly facilitate the attachment of the blue-lateral convergence magnet, and the magnet is configured in a disk-like shape, thereby minimizing irregularities of mag netization and attachment thereof.

Other objects, features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings.

Patented June 2, 1970 BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the reference numeral 1 represents a cylindrical frame including a large-diameter portion 2 and a small- diameter portion 3, 4 radially extending flanges provided on the periphery of the large- diameter portion 2, 5 axially extending notches formed in the largediameter portion at suitable positions, and 6 projections provided in the end portion of the large-diameter portion 2. The reference numeral 7 denotes a purity magnet held between the flanges 4 and the projections 6, '8 a recessed portion formed in the large-diameter portion 2 and having an axial groove 9' formed in the inner surface thereof, 10 a through-aperture formed in a corner portion of the recess 8, and 11 a leaf spring mounted in the recessed portion 8 with a bent portion 12 at the fore end thereof inserted in said through-aperture 10 and a curved portion 13 at the rear end thereof disposed in engagement with the end portion of a side wall 14 defining the recessed portion 8. The reference numeral 15 indicates a projection provided on the leaf spring, 16' a disk-like blue-lateral convergence magnet having a through-aperture formed in the center portion thereof, and 18 a cap-like magnet support provided in such a manner as to cover the magnet 16.

A shaft 19 provided at the center of the support 18 is inserted in the groove 9, and the projection 15 of the leaf spring 11 is disposed in engagement with the through-aperture 17 formed in the center portion of the magnet.

As described above, in the convergence device embodying the present invention, the blue-lateral convergence magnet is configured in disk-like shape, thus minimizing the possibility that the magnetic poles are dislocated during the magnetizing operation. Further, the device can be easily and economically manufactured since the recessed portion for holding the magnet can be formed integrally with the frame. In addition, the attachment of the bluelateral convergence magnet is extremely simple. The position where the magnet is supported can be accurately controlled by means of the leaf spring which is fixed with the bent portion provided on the fore end thereof being inserted in the through-aperture formed in one corner of the recessed portion. Thus, the magnet can be rotated in the recessed portion in a plane which is precisely perpendicular with respect to the axis thereof, so that the direc tion of the resulting electric field becomes parallel to that of the electron beams, whereby a geometrically balanced adjustment can be achieved resulting in a greatly improved blue-lateral convergence.

With the foregoing arrangement, the magnetic force can be utilized efiiciently so that the magnetization may be effected to the minimum required extent. Thus, it is possible to avoid adverse effect of the magnetic field such as deterioration in focusing, increased interference with respect to the red and green beams, etc. Furthermore, a smaller quantity of material is used such as in the fitting for attaching the magnet which tends to disturb the magnetic field produced by the latter, so that there is little or no possibility that the purity magnetic field is disturbed and the focusing is deteriorated.

Because of the disk-like configuration of the magnet, miniaturization of the magnet attaching portion as Well as the magnet itself can be achieved which in turn results in the convergence device being miniaturized. Thus, the adjustment of the purity magnet can be facilitated by virtue of the miniaturization of the blue-lateral convergence portion. 1

From the foregoing, it will be appreciated that the convergence device according to the present invention can produce the various foregoing effects and therefore it is extremely advantageous in respect of utility.

We claim:

1. A convergence device comprising a stepped cylindrical frame having a recessed portion in the larger diameter part thereof, a disc-like blue lateral convergence magnet having a central axially extending through aperture, a caplike magnet support covering said magnet and having a protruding portion in registry With one end of said aperture, said recessed portion having a groove along one surface thereof, said magnet being rotatably supported in said net support being engaged in said groove, an elastic leaf spring engaged with another surface of said recessed portion opposite to said one surface, said spring having a projection engaging said magnet at the end of said aperture opposite to said one end whereby said magnet is elastically supported by said spring in said recessed portion.

References Cited UNITED STATES PATENTS 2,500,455 3/1950 Fisher 313 77 XR 2,717,323 9/1955 Clay 335-212 XR 2,897,390 7/1959 Jensen 313-77 3,191,104 6/1965 Mak 335-210 GEORGE HARRIS, Primary Examiner US. Cl. X.R.

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