JPH062191Y2 - Convergence device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a convergence device for a color television receiver or a display.

(Prior Art) A conventional convergence device is,
As shown in No. 9481, a ring-shaped ferrite plastic magnet made of ferrite and plastic is attached to a holder attached to the neck portion of the color cathode ray tube.
The structure in which they are incorporated as one set is common.

(Problems to be solved by the invention) However, in the case of a convergence device using ferrite plastic magnets for all ring-shaped magnets, the temperature of the saturation magnetic flux density can be reduced if a degaussing material for temperature compensation is not provided. It has a coefficient of -0.18% / ° C, which makes it unsuitable for displays and cathode ray tubes of large color television receivers.

On the other hand, when a pair of plastic magnets having a temperature coefficient smaller than that of a ferrite plastic magnet, for example, an alnico plastic magnet having a general ring shape as shown in FIG. As shown in the magnetic flux density pattern of FIG. 5 (A) along the inner circumferential surface, the magnetic flux density in the neutral region (neutral zone) is not completely zero. Thus, if some magnetic flux density remains in the neutral region, it causes uncorrectable eccentricity of the beam of the cathode ray tube.
In other words, the minimum beam movement amount becomes large.

In view of the above points, the present invention uses alnico plastic magnets as at least one pair of magnets and has a temperature coefficient of the convergence device of ± 0.03 to 0.4% / ° C.
The present invention aims to suppress the following and also solve the problem of the magnetic flux density in the neutral region when the Alnico plastic magnet is adopted.

(Means for Solving the Problems) The present invention is a convergence device in which a plurality of pairs of ring-shaped plastic magnets are attached to the neck portion of a cathode ray tube, and at least one pair of ring-shaped plastic magnets is composed of alnico plastic magnets. At the same time, a notch is formed in the neutral region between the magnetic poles on the inner peripheral edge of the alnico plastic magnet, which solves the problems of the conventional technique.

(Operation) In the convergence device of the present invention, at least one pair of plastic magnets among a plurality of pairs of plastic magnets is configured by an alnico plastic magnet (temperature coefficient 0.03% / ° C) having excellent temperature characteristics. , The temperature characteristics can be better than the case where all magnets are composed of ferrite plastic magnets (temperature coefficient -0.18% / ° C), and the temperature coefficient of the convergence device is ± 0.03 to 0.04%. / ° C or less can be suppressed. Further, the problem of the magnetic flux density in the neutral region due to the adoption of the alnico plastic magnet is that a notch is formed in the neutral region between the magnetic poles at the inner peripheral edge of the alnico plastic magnet to reduce the influence of the residual magnetic flux density. Solvable. Further, it is not necessary to add another member for temperature compensation, which is suitable for downsizing.

Embodiment An embodiment of the convergence device according to the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of an embodiment of a convergence device,
FIG. 2 is a side view of the same, and FIG. 3 is a front view showing a ring-shaped four-pole alnico plastic magnet.

In these figures, 1 is a plastic holder, which is formed in a cylindrical shape and has a screw portion 2 at one end thereof. Further, the ring-shaped support 3 is integrated with the middle part of the holder. For the holder 1, a pair of ring-shaped two-pole plastic magnets (purity magnets)
4, ring-shaped non-magnetic plate 5, one pair of ring-shaped 6-pole plastic magnet (static magnet) 6, ring-shaped non-magnetic plate 7, one pair of ring-shaped 4-pole plastic magnet (static magnet) 8 and ring-shaped non-magnetic The plates 9 are fitted in this order, and finally the fixing plate 10 is attached to the screw portion 2
Each magnet is fixed by being screwed on. When the fixing plate 10 is loosened, the two-pole, four-pole, and six-pole plastic magnets are held in the holder 1 so that their rotations can be adjusted. Further, each non-magnetic plate 5, 7, 9 is engaged with the groove 12 of the holder 1 so as not to rotate.

Here, a pair of ring-shaped 4-pole plastic magnets 8
Is an Alnico plastic magnet (Alnico 8 and Alnico 5 are available, but Alnico 8 is particularly preferable) and is configured to have the shape shown in FIG. Ie 1
The pair of 4-pole Alnico plastic magnets 8 is 1 μm
Approximately 20 wt% of Alnico powder with a particle size of about 500 μm
% To 80 wt%, and plastic molding is performed. At the same time, notches 20 are formed in the inner peripheral edge portions of the neutral areas between the magnetic poles, and magnetized after molding (each magnetic pole is the inner circumference of the ring). Located in).

The remaining 2-pole and 6-pole plastic magnets 4 and 6 may be ferrite plastic magnets or other magnet materials.

The convergence device as described above is attached to the neck portion 15 of the color cathode ray tube, and is fixed to the neck portion 15 by tightening the tightening ring 11 to narrow the elastic end of the holder 1.

According to the configuration of the above embodiment, a pair of four-pole plastic magnets 8 (having a function of centering the red and blue beams), which have a great influence on the temperature coefficient of the convergence device, have a higher temperature than a ferrite plastic magnet. Since it is composed of an alnico plastic magnet whose characteristics do not change significantly, the temperature characteristics can be greatly improved. Further, the problem of the magnetic flux density in the neutral region between the magnetic poles that accompanies the alnico plastic magnet can be alleviated by forming the cutout portion 20 in the neutral region. That is, when the cutout portion 20 is formed, the magnet surface in the neutral region is separated from the inner circumference circle by the depth of the cutout portion 20, so that it follows the inner circumference circle of the 4-pole Alnico plastic magnet 8. The magnetic flux density pattern is as shown in Fig. 5 (B), which is equivalent to the existence of a neutral region where the magnetic flux density is substantially zero between the peaks of the magnetic poles. It is possible to minimize the minimum movement amount. In this way, the temperature characteristic of the convergence device and the minimum movement amount of the beam can be improved, and it can be suitably used for a large color cathode ray tube for display.

In the above embodiment, only one pair of ring-shaped quadrupole plastic magnets 8 are composed of alnico plastic magnets having the cutouts 20, but the three beams of red, green and blue of the color cathode ray tube are combined into one. If the pair of ring-shaped 6-pole plastic magnets 6 that play a role as well are also composed of alnico plastic magnets having a notch formed in the neutral region between the magnetic poles at the inner peripheral edge, the temperature characteristics can be further improved.

Further, the structure of a holder or the like for holding the two-pole, four-pole, and six-pole plastic magnets for rotation adjustment can be changed as appropriate.

(Effects of the Invention) As described above, according to the present invention, at least one pair of rings is provided in the structure in which a plurality of pairs (for example, 2 poles, 4 poles and 6 poles) of plastic magnets are attached to the neck portion of the cathode ray tube. -Shaped plastic magnet is composed of alnico plastic magnet, and notches are formed in the neutral area between the magnetic poles on the inner peripheral edge of the alnico plastic magnet, so the temperature characteristics are good and the minimum movement amount of the beam of the cathode ray tube is reduced as much as possible. Further, it is possible to obtain a high-performance convergence device applicable to displays and large-sized cathode ray tubes.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of a convergence device according to the present invention, FIG. 2 is a side view of the same, FIG. 3 is a front view showing a ring-shaped four-pole alnico plastic magnet in the embodiment, and FIG. A front view showing a general ring-shaped four-pole plastic magnet, FIG. 5 (A) is a waveform diagram showing a magnetic flux density pattern of a conventional ring-shaped four-pole alnico plastic magnet, and FIG. 5 (B) is an embodiment of the present invention. It is a wave form diagram which shows the magnetic flux density pattern of the ring-shaped 4-pole alnico plastic magnet in an example. 1 ... Holder, 1 ... Screw part, 3 ... Ring support, 4 ...
2-pole plastic magnet, 5, 7, 9 ... Ring-shaped non-magnetic plate, 6 ... 6-pole plastic magnet, 8 ... 4-pole alnico plastic magnet, 10 ... Fixed plate, 15 ...
Neck, 20 ... Notch.

Claims (1)

[Scope of utility model registration request] 1. A convergence device in which a plurality of pairs of ring-shaped plastic magnets are mounted on a neck portion of a cathode ray tube, wherein at least one pair of ring-shaped plastic magnets are made of alnico plastic magnets, and at the inner peripheral edge of the alnico plastic magnets. A convergence device having a notch formed in a neutral region between magnetic poles.