JPH0574368A - Color picture tube - Google Patents

Abstract

PURPOSE:To magnetize a magnetic body from the outside of a neck and correct static convergence and color purity, or the orbit of electron beams by forming the magnetizable magnetic body to be mounted on an electron gun into a cylin der having a length capable of forming a plurality of magnetic fields along a tube axis, with the magnetic poles being divided. CONSTITUTION:On an electron gun 4 in a neck 3, a magnetizable magnetic body 12 is formed into a cylinder having a length capable of forming magnetic field areas 14a, 14b along a tube axis Z, with the magnetic poles being divided. After sealing and exhausting, a magnetizing device is provided on the outside of the neck 3, and the magnetic body 12 is magnetized to provide the areas 14a, 14b. In this case, the area 14a is first provided, and an electron beam 5a shifted from the axis Z is curved in the axial direction. Thereafter, a picture tube is operated, and the intersection of the beam 5b to the axis Z is calculated from the result of measuring the point where the curved electron beam 5b reaches a phosphor screen 8 to determine the area 14b. Thus, static convergence and color purity or the orbit of the electron beam can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and in particular, a magnetic body is attached to an electron gun, and the magnetic body is magnetized from outside the neck to correct the orbit of an electron beam. Regarding picture tubes.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a color picture tube has an envelope composed of a panel 1 and a funnel 2 integrally joined to the panel 1, and is arranged in a neck 3 of the funnel 2. The three electron beams 5B, 5G, 5R emitted from the emitted electron gun 4 are deflected by the magnetic field generated by the deflection yoke 6 mounted on the outside of the funnel 2, and the panel 1
A phosphor screen 8 formed on the inner surface of the panel 1 through a shadow mask 7 arranged inside the
A structure for displaying a color image on the phosphor screen 8 is formed by vertical scanning.

In order to improve the quality of the color image drawn on the phosphor screen 8, the three electron beams 5B, 5G and 5R emitted from the electron gun 4 are concentrated on one point on the phosphor screen 8 ( It is necessary that the three-electron beams 5B, 5G, and 5R properly land the three-color phosphor layers constituting the phosphor screen 8 so that the desired color purity can be obtained. However, the actually manufactured color picture tube has three electron beams 5B, because of the assembly error of the electron gun 4 and the assembly error of the color picture tube itself.
The concentration of 5G and 5R and the landing on the three-color phosphor layer are deviated, and the screen quality deteriorates.

Therefore, a normal color picture tube is shown in FIG.
As shown in FIG. 5, a magnet 9 for correcting static convergence and landing deviation is attached to the outside of the neck 3. Usually, this magnet 9 is composed of three sets of permanent magnets, each set of two magnets having two poles, four poles and six poles along the periphery of a thin annular magnetic body. By rotating one set of two magnets and shifting their magnetic poles in the circumferential direction as appropriate, the trajectory of the electron beam is corrected, and static convergence and color purity are adjusted.

However, the adjustment of static convergence and color purity by three sets of permanent magnets having two sets of magnets as one set requires skill and considerable time is required for the adjustment, and the adjustment work is experienced. However, it is difficult to make accurate and sufficient adjustment.

As a means for compensating for the problem caused by the external magnet, Japanese Patent Laid-Open Publication Nos. 52-117512 and 55-1 have been proposed.
In Japanese Patent No. 8235, one or more magnetizable annular magnetic bodies are attached between the neck and the electron gun, and the magnetic bodies are provided with 2 poles, 4 poles, 6 poles, 8 poles from the outside of the neck. There is shown a color picture tube in which the polarities are polarized and magnetized and the orbit of the electron beam is similarly corrected to adjust the static convergence and color purity. However, this magnetic material has a short length in the direction along the tube axis, and therefore forms a multi-pole magnetic pole on the same plane, and each magnetic pole has a predetermined amount of magnetization without affecting other magnetic poles. It is difficult to magnetize. for that reason,
It is difficult to accurately and sufficiently correct static convergence and color purity.

Further, there is a color picture tube in which two or more magnetic bodies are arranged in the vicinity of the electron gun on the inner side of the neck so that they have different functions to correct the orbit of the electron beam.

As a color picture tube of this type, for example, in Japanese Patent Publication No. 1-38343, a first one is provided at the bottom of a convergence cup arranged at the electron beam emitting end of an electron gun.
In the color picture tube in which the second magnetic body is arranged in the opening, the color purity is corrected by the first magnetic body, and the static convergence is corrected by the second magnetic body. Also,
In Japanese Patent Laid-Open Publication No. 50-138734, in order to return the electron beam deviated from the tube axis (or the electron beam axis) onto the tube axis, two magnetic bodies are separated from each other in the direction along the tube axis. It is provided that the first magnetic body bends the electron beam deviated from the tube axis in the tube axis direction, and when the electron beam reaches the tube axis, the second magnetic body bends along the tube axis. ing.

However, it is disadvantageous to separately provide the two magnetic bodies in this manner because the manufacturing cost becomes high.
Particularly in the latter case (Japanese Patent Laid-Open No. 50-138734),
Since the arrangement positions of the first magnetic body and the second magnetic body are determined depending on the type of the electron gun, even if the electron beam is bent in the tube axis direction by the first magnetic body, it is the second magnetic body. It is difficult to adjust the positions of and so that they match the tube axis.

[0010]

As described above, in order to adjust the static convergence and color purity of the color picture tube, one or more magnetizable annular magnetic materials are provided outside the electrodes of the electron gun. There is a color picture tube in which this magnetic body is attached to the outside of the neck to form a predetermined magnetic pole. However, this magnetic material has a short length in the direction along the tube axis, and forms a multi-pole magnetic pole on the same plane.
There is a problem that it is difficult to magnetize each magnetic pole to a predetermined amount of magnetization without affecting other magnetic poles, and static convergence and color purity cannot be accurately and sufficiently corrected.

Further, two or more magnetic bodies are provided separately in the direction along the tube axis, and the electron beam diverged from the tube axis is bent by the first magnetic body in the tube axis direction and reaches the tube axis. Some of them are bent by the second magnetic body so as to be along the tube axis. However, if the two magnetic bodies are provided so as to be separated from each other, even if the electron beam is bent in the tube axis direction by the first magnetic body, That is the second
However, there is a problem that it is difficult to adjust the position of the magnetic body so that it is aligned with the tube axis.

The present invention has been made in view of the above problems, and a collar for attaching a magnetizable magnetic body to an electron gun and magnetizing the magnetic body from outside the neck to correct the electron beam trajectory. It is an object of the present invention to easily form a predetermined magnetic pole on the magnetic body of a picture tube so that the trajectory of an electron beam can be accurately and sufficiently corrected.

[0013]

An electron gun including a cathode and a plurality of electrodes arranged adjacently to the cathode is disposed in the neck, and at least one electron gun is provided in the electron gun.
In a color picture tube that has magnetizable magnets attached and that magnetizes the magnets to correct the trajectory of the electron beam emitted from the electron gun, there are several types of magnets in the direction along the tube axis. The magnetic body is formed in a cylindrical shape having a length capable of forming the magnetic field, and magnetic poles for generating a plurality of types of magnetic fields are sectioned in the magnetic body in the direction along the tube axis.

[0014]

As described above, when the cylindrical magnetic body having a length capable of generating a plurality of magnetic fields is arranged in the electron gun in the direction along the tube axis, the trajectory of the electron beam can be corrected. It is possible to easily form the required plural kinds of magnetic fields by dividing them in the direction along the tube axis.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

FIG. 1 shows a color picture tube which is an embodiment of the present invention. This color picture tube has an envelope composed of a panel 1 and a funnel 2 integrally joined to the panel 1, and an inner surface of the panel 1 is provided with a three-color phosphor layer which emits blue, green and red light. A phosphor screen 8 is formed, and a shadow mask 7 having a large number of electron beam passage holes formed therein is arranged so as to face the phosphor screen 8. An electron gun 4 that emits three electron beams 5B, 5G, and 5R is arranged in the neck 3 of the funnel 2. In addition, 6 is a 3 electron beam 5B, 5G emitted from the electron gun 4,
It is a deflection yoke that generates a magnetic field that deflects 5R.

As shown in FIG. 2, the electron gun 4 has three cathodes K (only one is shown), a heater H for individually heating these cathodes K, and a cathode H on the cathode K in the phosphor screen direction. A plurality of adjacent electrodes (first to fifth grids G1 to G5 in the illustrated example) are integrally fixed by a pair of insulating supports 11, and a convergence cup is attached to the fifth electrode G5 which is the final electrode. C is attached. In this electron gun 4, the cathode K and the first to third grids G1 to G3 control an electron emission from the cathode K and constitute an electron beam forming unit that focuses the emitted electrons to form an electron beam, The third and fifth grids G3 to G5 finally form a main lens portion for accelerating and focusing the electron beam toward the phosphor screen, and the fourth grid G4 serves as its focusing electrode.

In this color picture tube, one cylindrical magnetic body having a predetermined length along the tube axis (or electron gun axis) is provided outside the fourth grid G4, as described later.
Twelve are arranged. The magnetic body 12 is arranged inside the pair of insulating supports 11 in the illustrated example, but may be arranged inside the neck so as to surround the pair of insulating supports 11 together with the fourth grid G4.

This magnetic body 12 is mounted coaxially with the fourth grid G4 when the electron gun 4 is assembled,
After twelve attached electron guns 4 are sealed in a neck 4 of an envelope obtained by integrally joining (sealing) the panel 1 and the funnel 2, and exhausted to manufacture a color picture tube, By arranging and magnetizing a magnetizing device corresponding to the magnetic body 12 attached to the electron gun 4 outside the neck 4, the electron beam 5 based on the assembly error at the time of assembling the electron gun 4 and the color picture tube 5
It is used to correct the B, 5G, and 5R orbits.

Electron beams 5B, 5G, 5R by this magnetic body 12
3 (a), the magnetic field 12 is divided into two magnetic field regions 14a and 14b in the direction along the tube axis (Z axis), as shown in FIG. 3 (b). So that the electron beam 5a deviated from the tube axis is directed to the first magnetic field region on the cathode side.
The bending is performed by bending the electron beam 5b in the tube axis direction at 14a and along the tube axis in the second magnetic field region 14b on the phosphor screen side.

Such a correction method is disclosed in the above-mentioned Japanese Patent Laid-Open No. 50-
Although it is the same as the method disclosed in Japanese Patent No. 138734, the correction method in the color picture tube of this example is different in that one magnetic body 12 is provided with two magnetic field regions 14a and 14b.

That is, the conventional Japanese Patent Laid-Open No. 50-13873.
In the case of the publication No. 4, two magnetic bodies are provided apart from each other along the tube axis, and the electron beam deviated from the tube axis by the first magnetic body is bent in the tube axis direction. The method is to bend the second magnetic material along the tube axis when it reaches the tube axis. However, since the positions of the two magnetic materials are determined with respect to the electron gun, the electron beam deviated from the tube axis. Even if the first magnetic material is bent in the tube axis direction, the bent electron beam
Does not always coincide with the tube axis at the position where the magnetic body is arranged, and the first magnetic body may be magnetized so that the electron beam coincides with the tube axis at the position where the second magnetic body is arranged. difficult.

On the other hand, as in the color picture tube of this example, the length of the magnetic body 12 in the direction along the tube axis is increased to 1
When two magnetic field regions 14a and 14b are provided in one magnetic body 12,
The electron beam 5a deviated from the tube axis by the first magnetic body is bent in the tube axis direction, and then the color picture tube is operated to measure the point where the bent electron beam 5b reaches the phosphor screen 8, The second magnetic field region 14b can be determined by calculating the point where the electron beam 5b intersects the tube axis from the measurement result. Therefore, it is possible to solve the problem that occurs because the position of the magnetic body is fixed as in the conventional case. That is, the length of one magnetic body 12 is defined so that two magnetic fields can be formed in the direction along the tube axis.
If the magnetic poles are arranged outside of, the magnetic poles that correct the trajectory of the electron beam can be easily formed.

In this example, for the sake of simplification of description, the correction method for the single electron beam has been described, but it goes without saying that the correction is similarly performed for the correction of three electron beams.

Next, another embodiment will be described.

FIG. 4 shows one cylindrical magnetic body 12 having two poles, four poles and six poles in order to adjust the static convergence and color purity of the color picture tube which emits the three electron beams 5B, 5G and 5R. This is the case of magnetizing the magnetic pole. Regarding the adjustment of the static convergence and the color purity, in the conventional method, 8 magnetic poles or 12 magnetic poles are formed as a total magnetic field of 2 magnetic poles, 4 magnetic poles and 6 magnetic poles in one magnetic body. However, since the conventional magnetic material has a short length in the direction along the tube axis, if an attempt is made to adjust the total magnetic field by forming 8 or 12 magnetic poles, the static convergence and color purity can be adjusted. It is difficult to independently magnetize the required two-pole, four-pole, and six-pole magnetic poles without affecting each other, and it is difficult to form a magnetic pole that accurately and sufficiently adjusts the static convergence and color purity. It was

However, the magnetic body 12 of this example is long in the direction along the tube axis, and therefore is formed by dividing the first to third three magnetic field regions 14a, 14b, 14c in the direction along the tube axis. , 2 poles, 4 poles, and 6 poles are formed respectively. In this case, before magnetizing the magnetic body 12, by irradiating a laser from the outside of the neck in advance to the position where the magnetic pole is to be formed, locally heating the magnetic material to a temperature below the magnetic transformation point or to the extent that spontaneous magnetization disappears, After that, the position may be magnetized by a magnetizing device. As a result, the magnetic poles can be independently magnetized without affecting each other, and the magnetic poles that accurately and sufficiently adjust the static convergence and the color purity can be easily formed.

In the second embodiment, before the magnetization, the laser is irradiated to the position where the magnetic pole is to be formed, and the laser is locally heated below the magnetic transformation point or to the extent that the spontaneous magnetization disappears. After that, the magnetic pole was formed by magnetizing with a magnetizing device, but the magnetizing method of this magnetic body is not limited to this, and the magnetic pole may be formed by another magnetizing method.

In the second embodiment, in order to adjust the static convergence and color purity of the color picture tube,
Although three magnetic field regions are formed in one magnetic body along the tube axis, magnetic poles for adjusting static convergence and color purity can be formed in two magnetic field regions. For example, a two-pole magnetic pole for mainly adjusting the color purity is formed in the first magnetic field area on the cathode side, and an eight-pole magnetic pole for mainly adjusting the static convergence is formed in the second magnetic field area on the phosphor screen side. Once formed, the magnetic poles required for static convergence and color purity adjustment can be formed very quickly.

The shape and position of the magnetic material are not limited to those in the above embodiments.

Further, in each of the above-mentioned embodiments, the case where one magnetic body is arranged has been described. However, instead of this one magnetic body, two or more magnetic bodies may be arranged closely. 1
The same effect as in the case of individual magnetic bodies can be obtained.

[0032]

When the magnetic body attached to the electron gun has a cylindrical shape having a length capable of forming a plurality of magnetic fields in the direction along the tube axis, the static convergence and color purity of the color picture tube are corrected, or the It is possible to easily form a plurality of types of magnetic fields necessary for correcting the beam trajectory by dividing them in the direction along the tube axis.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube which is an embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of magnetic bodies with respect to the electron gun.

FIG. 3 (a) is a diagram showing the arrangement of magnetic field regions formed in the magnetic body when adjusting the trajectory of the electron beam;
FIG. 3B is a diagram for explaining a method of forming the magnetic field region.

FIG. 4 is a diagram showing an arrangement of magnetic field regions for adjusting static convergence and color purity of a color picture tube.

FIG. 5 is a diagram showing a configuration of a conventional color picture tube.

[Explanation of symbols]

 3 ... Neck 4 ... Electron gun 5B, 5G, 5R ... 3 Electron beam 8 ... Phosphor screen 11 ... Insulating support 12 ... Magnetic material 14a ... First magnetic field area 14b ... Second magnetic field area C ... Convergence cup G1 ... 1st grid G2 ... 2nd grid G3 ... 3rd grid G4 ... 4th grid G5 ... 5th grid K ... cathode

Claims (1)

[Claims] 1. An electron gun comprising a cathode and a plurality of electrodes arranged adjacently to the cathode is arranged in the neck, and at least one magnetizable magnetic material is attached to the electron gun. In a color picture tube that magnetizes this magnetic body to correct the trajectory of an electron beam emitted from the electron gun, the magnetic body is a tube having a length capable of forming a plurality of types of magnetic fields in the direction along the tube axis. A color picture tube characterized in that the magnetic body is formed into a plurality of magnetic poles that generate a plurality of types of magnetic fields in a direction along the tube axis.