JPH0370335B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for magnetizing a neck magnet of a color cathode ray tube, which magnetizes a neck magnet attached to the outer periphery of a neck portion housing an electron gun. .

[Prior Art] Conventionally, in-line type color cathode ray tubes in which multiple (usually three) electron guns are arranged in the same plane are often used. It requires a two-pole magnet used for power adjustment and a four-pole or six-pole magnet for static convergence adjustment.

This device is designed to eliminate errors associated with the assembly of color cathode ray tubes. In other words, when the three electron beams deviate from their predetermined positions relative to the phosphor screen, It has a correction function to ensure a perfect match. Usually, the above-mentioned magnet is made by stacking two ring-shaped magnetized two-pole, four-pole, and six-pole magnets so that the magnetic poles are in opposite directions, and attaching these to the outer periphery of the neck. The adjustment method is to have the magnetic poles completely overlap each other and cancel out their magnetization, while a pair of two
You can shift the two magnets from a completely overlapping state to adjust the opening angle and set the strength of the magnetic field generated at that opening angle, or you can rotate the magnets together while keeping the opening angle constant. This changes the direction of the magnetic field. Then, the three electron beams are moved by the same amount in the same direction using a bipolar magnet, and each electron beam accurately strikes a predetermined phosphor dot to cause it to emit light, thereby performing so-called purity adjustment.

In addition, a quadrupole magnet can give the same amount of change to the electron beams on both sides in opposite directions without affecting the center one of the three electron beams. electron beams can be overlapped at the center of the phosphor screen. Furthermore, 6
Polar magnets can also make the same amount of change in the same direction on both sides without affecting the central electron beam, thereby superimposing the electron beams on both sides onto the central electron beam. becomes possible. Static convergence adjustment is performed using the 4- and 6-pole magnets mentioned above.

In the above-described in-line type color cathode ray tube, before the first operation starts, it is necessary to rotate a total of six magnets of the three types described above on the neck portion and fix them at the best points.

This adjustment is normally done individually while looking at the color cathode ray tube screen, but it is difficult to fully automate it, and in addition, six magnets are made to be rotatable on the neck during adjustment, and fixed after adjustment. This requires a complicated holding mechanism, which increases the cost of color cathode ray tubes. As a countermeasure for this,
In recent years, a ring-shaped magnet member (for example, a sheet-shaped magnetic material fitted around the outer periphery of the neck part) is placed in the neck part, and this is magnetized according to the characteristics of each color cathode ray tube. A method has been proposed.

According to this method, a magnet member that has not been magnetized is attached to the neck portion, and then a magnetizing device is brought close to the magnet member, and a current is passed through the magnetizing device to magnetize it.

This type of magnetization method will be explained below.

FIG. 1 is a diagram showing a color cathode ray tube equipped with a net magnet, and the color cathode ray tube 1 includes a panel 2 provided with a fluorescent screen, and a funnel 3 joined to the panel 2 to form an approximately pyramidal shape. , and a cylindrical neck portion 4 connected to the funnel 3 are integrated, and an electron gun 5 for emitting a plurality of electron beams is installed on the same straight line inside the neck portion 4. Further, a deflection yoke 6 is attached near the connecting portion between the funnel 3 and the neck portion 4, and on the other hand, a neck magnet 10 for adjusting the orbit of the electron beam is attached to the outer periphery of the neck portion 4 behind the deflection yoke 6. . The net magnet 10 is made of a magnetic material with a large coercive force, such as a so-called plastic magnet or a rubber magnet formed by mixing barium ferrite into a resin.

As a method of magnetizing the net magnet 10, for example, in the static magnetization method, as shown in FIG.
The conductor 21 is wound around the core 24, and
Using a magnetizing head 30 consisting of a coil 20 connected to a variable power source 23 via a switch 22, this magnetizing head 30 is connected to a plurality of (generally 8 to 12 or more) net magnets 10. They are set and magnetized accordingly. That is, the color cathode ray tube is operated to determine the necessary correction amount of the electron beam, the amount of partial magnetization of the net magnet 10 is calculated by an appropriate method, and the current necessary for this magnetization is made to flow. Variable power supply 23 connected to individual coils 20
is set and current is applied for an appropriate time using the switch 22 to obtain the required magnetization.

However, the biggest drawback of the above method is that the net magnet must be magnetized over the entire axial direction of the net magnet, so the magnetic flux used for magnetization must be extremely large, and a magnetizing device is required. This means that it will become larger. Also, the magnetizing head 3
0 is used repeatedly, the temperature of the coil 20 and core 24 due to the current increases, and although a constant current value is required, the current value changes with the temperature, making it difficult to obtain an accurate amount of magnetization. I couldn't get it. Furthermore, since the magnetic field of the core 24 disturbs the magnetic field around the color cathode ray tube, such as the earth's magnetism, the magnetization head is 30 must be placed quite far away from the color cathode ray tube. Therefore, a plurality of magnetizing heads 30
It also had the disadvantage of requiring a large-scale mechanism to move it.

On the other hand, in the conventional method using the so-called rotational magnetization method, as shown in FIG.
and has a gap 25,
Using a magnetizing head 30 that can go around the neck part 4, the magnetizing head 30 is maintained at a constant distance from the neck magnet 10, and the gap 25 is
The central plane T (meaning the central plane perpendicular to the main magnetic flux generated in the gap 25) is set so as to always pass through the central axis of the neck portion 4. In this state, while circulating around the neck magnet 10, the amount of current supplied from the variable power source 23 is increased or decreased in accordance with the required magnetization distribution.

In this method, the magnetization distribution of the neck magnet 10 in the vicinity of the gap 25 is microscopically very complicated, but when the neck magnet 10 is moved around in one direction, each part of the neck magnet 10 is , the magnetization received just before passing through the gap 25 and losing its influence will ultimately remain. For example, as shown in FIG. 3, if you want to magnetize with the magnetization vector pointing outward from the center of the neck part 4, you can fix the current flowing through the coil 27 in an appropriate direction and move the magnetization head 30. , where the gap 25 is approaching, the magnetization is directed toward the center, contrary to the desired direction, and on the other hand,
Immediately below the gap 25, the desired perpendicular magnetization occurs, and after the gap 25 has almost passed, the desired outward magnetization occurs. Here, in order to reliably change the magnetization from the desired direction perpendicular to the desired direction, the material of the neck magnet 10 must have a magnetic anisotropy in which the axis of easy magnetization is in a radial direction from the center of the neck portion 4. It is preferable to use a flexible material.

In the above-mentioned rotary magnetization method, since the magnetic flux for magnetization can be concentrated in the gap 25, there is an advantage that the magnetization device itself can be relatively small. However, the disadvantage of this method is that undesired magnetization remains near the position where the magnetization head 30 was last stopped, with the magnetization vector not reversing, making it difficult to obtain the necessary correction completely thereafter. There are many things that can be mentioned. In addition, with this method, when the distribution of the amount of magnetization is inappropriate for the same reason, it is difficult to partially correct the net magnet 10, and the magnetization cannot be corrected completely. Another drawback is that it is necessary to re-magnetize the entire circumference.

[Summary of the Invention] The present invention has been made in order to eliminate the above-mentioned conventional drawbacks, and the present invention is made by making the center plane of the gap perpendicular to the main magnetic flux generated in the gap perpendicular to the central axis of the neck part and making the gap close to each other. By moving the magnetizing head parallel to the central axis while applying current to the coil, it is possible to reliably obtain the desired magnetization of the neck magnet even with a magnetizer with a relatively simple structure, and to improve the magnetization. It is an object of the present invention to provide a method for magnetizing a neck magnet of a color cathode ray tube, which can automate correction and adjustment work after the operation of the color cathode ray tube.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. In FIG. 4, the magnetizing head 30 is
Similar to the conventional example shown in FIG. 3, the coil 27 is wound around a core 26 and has a gap 25. However, the gap 25 of the magnetizing head 30 is
Its central plane T is perpendicular to the central axis of the neck portion 4 and is disposed close to the neck magnet 10.
Here, it goes without saying that the gap 25 may be in close contact with the neck magnet 10.

In magnetizing according to this embodiment, the magnetizing head 30 is attached to the coil 27 in the longitudinal direction of the neck portion 4 over a range larger than the width W of the neck magnet 10, for example, from A to B. Move it while applying an appropriate current. That is, the movement of the magnetizing head 30 ends with the gap 25 starting from behind the neck magnet 10 and moving forward in the direction of the arrow. The process of magnetization on the magnetizing head 30 due to this is the same as that explained in FIG. Accurate magnetization distribution can be obtained without residual magnetization.

At this time, as a matter of course, the magnetizing head 30 can only magnetize, for example, a width portion indicated by D in FIG. 4B. Therefore, magnetization over the entire circumference is carried out by moving the magnetizing head 30 little by little in the circumferential direction above the neck magnet 10 and repeating the movement several times.

Therefore, according to the above method, the net magnet 1
Not only can you avoid an undesired magnetized state at the end of magnetization above 0, but you can also re-magnetize only one magnetized part along the central axis of the network part 4, depending on the screen situation. The amount of magnetization can be easily corrected accurately. Furthermore, if necessary, the part where the magnetizing head 30 was run previously and the part where the magnetizing head 30 was moved may be
It is also possible to increase the degree of freedom in correction by slightly shifting the part where 0 is run.

In addition, in the above embodiment, one magnetizing head 30
However, the present invention is not limited to this, and a plurality of magnetizing heads 30 of the same shape may be arranged surrounding the neck magnet 10. In this case, even if a large number of magnetizing heads 30 are used, the magnetic flux generated by each magnetizing head 30 is concentrated in the gap 25, so that
The magnetizing head 30 is the magnetizing head 3 explained in FIG.
It never becomes larger than 0.

Further, as the material for the neck magnet 10, it is preferable to use a magnetically anisotropic material whose axis of easy magnetization is in a radial direction from the central axis of the neck portion 4. As a result, an integrated neck magnet 10 can be used, and cost reduction can also be realized.

Furthermore, a typical procedure for magnetizing the net magnet 10 is to attach the color cathode ray tube to a color television (not shown) and then magnetize it. Part 4
It may be difficult to secure sufficient space around the In such a case, if the core 26 of the magnetic head 30 is bent in the opposite direction to the direction A of the phosphor screen, as shown in FIG. The space can be used for magnetization.

[Effects of the Invention] According to the present invention, it is possible to accurately obtain the desired magnetization of the net magnet with a magnetization machine having a relatively simple structure, and it is also possible to correct the magnetization and make adjustments after the operation of the color cathode ray tube. Work can be automated.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing a conventional color cathode ray tube.
Fig. 2 is an explanatory diagram showing a conventional method of magnetizing the neck magnet of a color cathode ray tube, Fig. 3 is an explanatory diagram illustrating another conventional magnetizing method, and Fig. 4 is an explanatory diagram showing an embodiment of the present invention. The method of magnetizing the neck magnet of a color cathode ray tube is shown, FIG. 4A is a side view, FIG. 4B is a cross-sectional view,
FIG. 5 is a side view showing another embodiment of the invention. 4...Network portion, 5...Electron gun, 10...Network magnet, 25...Gap, 26...Core, 27
... Coil, 30 ... Magnetizing head (magnetizing device).
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. In a method for magnetizing a neck magnet of a color cathode ray tube, which magnetizes a neck magnet attached to the outer periphery of a neck portion housing an electron gun, the magnetization is performed using a coil wound around a core. Using a magnetizing head configured with a gap at the top, the center plane of the gap, which is perpendicular to the main magnetic flux generated in the gap, is made perpendicular to the central axis of the neck part, and the gap is brought close to the neck magnet, A method for magnetizing a neck magnet for a color cathode ray tube, which comprises moving a magnetizing head parallel to the central axis while passing a current through the coil. 2. A method of magnetizing a neck magnet for a color cathode ray tube according to claim 1, wherein the moving distance of the magnetizing head is set to be larger than the width of the neck portion of the neck magnet in the direction of the central axis.