JPH0554823A - Quadrupole magnetic field generator and method of centralized adjustment using the same generator - Google Patents

Abstract

PURPOSE:To decrease the focal difference between a center and an outside electron gun by forming a quadrupole magnetic field generator of a ring-shaped magnet the two N poles of which are formed at a predetermined angle interval to each other and another ring-shaped magnet the two S poles of which are formed at a predetermined angle interval to each other. CONSTITUTION:A quadrupole magnetic field generator 8 is formed by ring-shaped magnets 8a, 8b which are magnetized in such a way that the two N (or S) poles of the magnet 8a (or 8b) are opposite at their insides to each other at an angle interval of 180 deg.. N-pole magnetons 25, 26 are provided at an angle interval of 180 deg. to each other on the magnet 8a and S-pole magnetons 27, 28 are provided at the same angle interval on the magnet 8b. The angle theta of adjustment of the generator 8 is limited within the range of either 0<theta<90 deg. or 90 deg.<theta<180 deg. so that outside electron beams 11r, 11b are subjected to centralized correction. Therefore, forces that the magnetic flux of the generator 8 exerts on the beams differ and the effect of improving resolving power through the centralized correction can be intensified for either a central electron beam or an outside electron beam and the difference in the focus characteristic between the center and outside electron guns can be decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quadrupole magnetic field generator for performing concentrated correction of an in-line type color cathode ray tube, and a concentrated adjustment method using the quadrupole magnetic field generator.

[0002]

2. Description of the Related Art FIG. 6A shows, for example, Japanese Patent Publication No. 2-13.
It is sectional drawing which shows the in-line type color cathode ray tube shown by No. 36. In the figure, 1 is a cathode ray tube, 2 is a fluorescent screen,
3 is a panel, 4 is a shadow mask, 5 is a funnel, 6
Is a neck, 7 is an in-line type electron gun structure, and 8c is a quadrupole magnetic field generator, which is supported by a frame 9 mounted around the neck 6. 10 is a deflection yoke, 11r, 1
1b is an outer electron beam of red and blue, 11g is a central electron beam of green, and 12 is a tube axis of the cathode ray tube 1.

Usually, in an in-line type color cathode ray tube,
Although the horizontal deflection magnetic field formed by the deflection yoke 10 is set to the pincushion type and the vertical deflection magnetic field is set to the barrel type, a self-convergence method for correcting the concentration deviation of the three electron beams in the entire scanning screen is realized. , By passing through such an inhomogeneous magnetic field and being deflected, the electron beam spot undergoes so-called deflection distortion and is horizontally distorted for a long time.
Aberration called halo is likely to occur. In particular, this tendency is large in the peripheral portion of the scanning screen, and there is a drawback that the resolution is greatly deteriorated.

The invention of Japanese Examined Patent Publication No. 2-1336 is made in view of such drawbacks. For example, three electron beams are radiatively focused by the in-line type electron gun structure 7 and the quadrupole magnetic field generator 8c. When there is no concentration correction action due to, the three electron beams 11r, 11g, and 11b never intersect on the shadow mask 4 or the phosphor screen 2, but are almost on the tube axis 12 and on the panel 3 side from the phosphor screen 2. The outer electron beams 11r and 11b are set to intersect each other, that is, to be insufficiently concentrated so that the three electron beams 11r, 11g, and 11b are concentrated on the phosphor screen 2 by the quadrupole magnetic field generator 8c. The centralized correction is made in the direction of the electron beam 11g.

At this time, since each electron beam receives a horizontal pressure and a vertical attractive force from the magnetic field generated by the quadrupole magnetic field generator 8c, the electron beam spot shape at the central portion of the scanning screen becomes vertically long, while the peripheral portion of the scanning screen becomes vertical. Then, the deflection distortion and the halo are improved, and if the vertical length ratio (ratio of the vertical diameter to the horizontal diameter) of the electron beam spot in the central portion of the scanning screen is set to 1.1 to 2.0, high resolution can be obtained over the entire scanning screen. It is to be obtained.

FIG. 6B shows a conventional quadrupole magnetic field generator 8c.
In the exploded perspective view of FIG. 1, it is composed of a pair of four-pole magnetized annular magnets 8d and 8e, and each annular magnet 8d and 8e includes
As shown, the N-pole magnets 13, 14, 1 are arranged at 90-degree angular intervals.
9, 20 and S pole magnets 15, 16, 17, 18 are arranged alternately.

FIG. 7 is a diagram for explaining the action of each electron beam when concentrated correction is performed using such a conventional quadrupole magnetic field generator 8c, and a pair of annular magnets 8d. , 8e are rotated relative to each other by an appropriate angle to generate magnetic fluxes 23a, 23b, 24a, 24b, and these magnetic fluxes 23a-24b cause the outer electron beam 1 to be insufficiently concentrated with respect to the central electron beam 11g.
1r and 11b are concentratedly corrected, but at the same time, the three electron beams are subjected to horizontal pushing force and vertical pulling force by the magnetic fluxes 23a to 24b as shown by arrows in the figure, and the center of the scanning screen. In, the electron beam spot becomes vertically long, which improves the deflection distortion and halo around the scanning screen.

[0008]

Although the conventional in-line type color cathode ray tube is constructed as described above, the concentrated correction amount by the quadrupole magnetic field generator is unique to one in-line type color cathode ray tube. However, there is a drawback that it is difficult to make the resolution improving effect by the centralized correction the same between the outer electron gun and the central electron gun.

The reason for this will be described with reference to FIG. The conventional quadrupole magnetic field generator 8c rotates the outer ring-shaped magnets 8d and 8e to each other to rotate the outer electron beams 11r and 1e.
1b is concentratedly corrected, but the magnetic poles of the quadrupole magnetic field formed at this time are the same magnetic elements close to each other between the annular magnets 8d and 8e, for example, 13 and 20, 16 and 18 in the figure. 1
They are located exactly in the middle of 4 and 19, and 15 and 17 to form N pole, S pole, N pole and S pole, respectively. Then, among these, the straight lines 21 and 22 connecting the same magnetic poles intersect substantially on the tube axis 12, and the three electron guns are arranged in the direction (hereinafter, referred to as "X").
The angle (hereinafter, referred to as “adjustment angle”) θ formed in a direction (hereinafter, referred to as “Y-axis direction”) perpendicular to the “axial direction” is 1
There can be only one, approximately 90 degrees.

The strength of each magnetic pole of the quadrupole magnetic field formed on the straight lines 21 and 22 is determined by the mutual rotation angle of the annular magnets 8d and 8e, which is also the outer electron beam 11
It is uniquely determined by the amount of insufficient concentration of r and 11b. That is,
When the conventional quadrupole magnetic field generator 8c is used to intensively correct the insufficiently concentrated outer electron beams 11r and 11b, the distribution of the quadrupole magnetic field formed is uniquely determined. The resolution improving effect by the correction is uniquely determined for both the outer electron gun and the central electron gun.

Further, the horizontal pushing force and the vertical pulling force which are normally received from the quadrupole magnetic field are different between the outer electron beam and the central electron beam due to the difference in the positional relationship between the three electron beams and the magnetic poles. Therefore, when attempting to improve the resolution using the conventional quadrupole magnetic field generator 8c, in order to make the resolution improving effects of the outer electron gun and the central electron gun the same after the concentrated correction is completed, It is necessary to accurately set the insufficient concentration amount of the beams 11r and 11b to a predetermined value.

However, in the in-line type electron gun assembly, due to variations in the assembly accuracy of the electrode portion (not shown) that electrically or mechanically concentrates the outer electron beam, variations in the dimensional accuracy of the electrode parts, etc., It is difficult to set the amount of insufficient concentration with high accuracy, and even if the amount of insufficient concentration can be set to a predetermined value with high precision, an electrode unit (not shown) that forms an electrostatic or magnetostatic focusing lens. Since there is a variation in the assembly precision of (1) and a variation in the electrode dimensions thereof, the conventional method for improving the resolution by concentrated correction of the quadrupole magnetic field generator 8c causes a difference in effect between the outer electron gun and the central electron gun. This often results in a difference in resolution between the outer electron gun and the central electron gun.

That is, in the outer electron gun and the central electron gun, one has good deflection distortion and halo as shown in FIG. 8A, and the other has the electron beam spot as shown in FIG. 8B. Although 29 is almost a circle in the center of the scanning screen, the deflection distortion and the halo 30 are large around the scanning screen.
There is a problem in that it is difficult to compromise the focus characteristics between the electron guns.

Further, regarding the definition of the vertical ratio of the electron beam spot at the center of the scanning screen to 1.1 to 2.0 (meaning that it is long in the Y-axis direction), the shape of the electron beam spot is the above-mentioned concentration. In addition to correction, it is affected by various resolution improvement measures applied to the in-line type electron gun structure,
The concentrated correction does not always make the image vertically long, and it is not desirable that the electron beam spot becomes vertically long with respect to the resolution at the center of the scanning screen. Therefore,
In addition to the portrait ratio, an index that is a guideline for resolution improvement was needed.

The present invention has been made in order to solve the above-mentioned problems, and the outer electron gun and the central electron generated during the concentrated correction are left while the resolution improving effect of the concentrated correction by the conventional quadrupole magnetic field generator is left. It is an object of the present invention to obtain a quadrupole magnetic field generator capable of reducing the difference in focus characteristics between guns, and to obtain a convergence adjusting method using this quadrupole magnetic field generator.

[0016]

An in-line type color cathode ray tube according to the invention of claim 1 is formed so that two N poles face inward at an angle of 180 degrees around a neck of the cathode ray tube. And a second annular magnet in which two south poles are formed so as to face each other inward at an angular interval of 180 degrees. It is characterized by having a polar magnetic field generator.

According to a second aspect of the present invention, when the quadrupole magnetic field generator according to the first aspect is used for concentrated adjustment, an in-line type electron gun structure for minimizing the lateral diameter of the electron beam spot in the X-axis direction at the center of the phosphor screen. When the value obtained by subtracting the applied voltage to the focusing electrode that minimizes the longitudinal diameter in the Y-axis direction from the applied voltage to the focusing electrode of is defined as the aberration coefficient, the aberration coefficient of each electron gun is 0 to 300.
In the case where the aberration coefficient becomes smaller in the outer electron gun than in the central electron gun when the outer electron beam is concentratedly corrected by using the conventional quadrupole magnetic field generator while being set to be within the range of v, Concentration correction of the outer electron beam is performed so that the adjustment angle θ of the quadrupole magnetic field generator is 90 ° <θ <180 °, and conversely, the outer electron beam is concentrated using the conventional quadrupole magnetic field generator. When the aberration coefficient becomes smaller in the central electron gun than in the outer electron gun after the correction, the adjustment angle θ of the quadrupole magnetic field generator is set to 0 ° <θ <90 °, and the outer electron beam concentration is corrected. It was designed to do.

[0018]

According to the invention of claim 1, the adjustment angle θ of the quadrupole magnetic field generator is set to 0 ° <θ <90 ° or 90 ° <θ <1.
Since the outer electron beam is concentratedly corrected by limiting it to a range of 80 °, the force exerted by the magnetic flux of the quadrupole magnetic field generator on the electron beam is different. It becomes stronger with either the central electron gun or the outer electron gun.

Further, according to the invention of claim 2, the aberration coefficient, which is an index for the resolution of each electron gun of the in-line type electron gun structure, is set to 0 to 300 v for each electron gun. Excessive vertical length of the beam spot and deflection aberration and halo around the scanning screen can be suppressed in a good balance, and good resolution can be obtained over the entire scanning screen.

[0020]

【Example】

Example 1. An embodiment of the present invention will be described below. Figure 1
1A is a sectional view of an embodiment of the present invention, and FIG. 1B is an exploded perspective view showing the configuration of the quadrupole magnetic field generator.
12 to 12 are the same as the conventional example shown in FIG. In the figure, 8 is a quadrupole magnetic field generator, which is composed of annular magnets 8a, 8b in which two north or south poles are magnetized so as to face inward at an angular interval of 180 °,
On the ring-shaped magnet 8a, there is N inward at 180 degree angular intervals.
The pole magnets 25, 26 are provided on the annular magnet 8b by 18
S-pole magnets 27 and 28 are formed on the inner side at an angle interval of 0 degree, and these two annular magnets 8a and 8b are formed.
Rotate each other to generate a quadrupole magnetic field generator,
It is configured to collectively correct the outer electron beam.

In the in-line type color cathode ray tube 1 constructed as described above, in order to concentrate and correct the outer electron beams 11r and 11b which are previously set to be insufficiently concentrated, an appropriate quadrupole magnetic field is applied around the electron beam. Although it is necessary to generate the magnetic poles of the quadrupole magnetic field formed by the quadrupole magnetic field generator 8, the magnetic poles of the ring-shaped magnets 8a and 8b are the magnetic poles themselves. Is constant, and unlike the conventional quadrupole magnetic field generator, the magnetic pole strength cannot be changed by the mutual rotation angle of the annular magnets. Therefore, in order to form the quadrupole magnetic field corresponding to the insufficient concentration amount of the outer electron beams 11r and 11b by the quadrupole magnetic field generator 8, each magnet of the annular magnets 8a and 8b is converted into the outer electron beams 11r and 11b. On the other hand, it is necessary to position it at an appropriate position.

Next, the action of each electron beam when the outer electron beams 11r and 11b are concentratedly corrected by the quadrupole magnetic field generator 8 will be described with reference to FIGS. 2 (a) and 2 (b). The straight lines 21 and 22 connecting the same magnetic poles are equal to the straight lines 21 and 22 connecting the same magnetic elements of the quadrupole magnetic field generator 8,
The straight lines 21 and 22 substantially intersect with each other on the tube axis 12 and form an adjustment angle θ in the Y-axis direction.

In FIG. 2A, the adjustment angle θ1 is 0 °.
In the range of <θ1 <90 °, the magnetic elements 25, 26, 27, 28 of the quadrupole magnetic field generator 8 generate magnetic fluxes 23c, 23d, 24.
c and 24d are generated. Of these, the magnetic fluxes 23c, 2 are responsible for the concentration correction of the outer electron beams 11r, 11b.
3d, and by adjusting the adjustment angle θ1 within the above range, the magnetic flux 23 with respect to the outer electron beams 11r and 11b can be adjusted.
The strengths and positions of c and 23d can be optimized, and as a result, the outer electron beams 11r and 11b can be concentratedly corrected. That is, there is an adjustment angle θ capable of collectively correcting the outer electron beam in the range of 0 ° <θ <90 °.

At this time, each electron beam is vertically elongated at the center of the scanning screen by receiving a horizontal pushing force and a vertical attractive force as shown by arrows, but the magnetic fluxes 24c and 24d are emitted from the outer electron beams 11r and 11b. Since the outer electron beams 11r and 11b are located far away from each other, the vertical attractive force of the outer electron beams 11r and 11b is smaller than that of the central electron beam 11g.
The central electron beam 11g is more likely to be vertically elongated at the center of the scanning screen than the r and 11b. That is, the central electron gun has a larger effect of improving the resolution by the centralized correction than the outer electron gun.

In FIG. 2B, the adjustment angle θ2 is 90.
In the range of ° <θ2 <180 °, the magnetic elements 25, 26, 27, 28 of the quadrupole magnetic field generator 8 generate magnetic fluxes 23e, 23f,
24e and 24f are generated. Of these, the magnetic flux 23 controls the concentration of the outer electron beams 11r and 11b.
By adjusting the adjustment angle θ2 within the above range, the strength and position of the magnetic fluxes 23e and 23f with respect to the outer electron beams 11r and 11b can be optimized.
The outer electron beams 11r and 11b can be concentratedly corrected. That is, there is an adjustment angle θ capable of collectively correcting the outer electron beam in the range of 90 ° <θ2 <180 °.

At this time, each electron beam is vertically elongated at the center of the scanning screen due to the horizontal pushing force and the vertical attractive force as shown by the arrow, but the magnetic fluxes 23e and 23f are far from the central electron beam 11g. Since the central electron beam 11g is positioned, the horizontal pushing force received by the central electron beam 11g is
Since it is smaller than that of 11b, the central electron beam 11g
The outer electron beams 11r and 11b are more likely to be vertically elongated in the center of the scanning screen. That is, the outer electron gun has a larger effect of improving the resolution by the centralized correction than the central electron gun.

As described above, according to the in-line type color cathode ray tube of this embodiment, the range of the adjustment angle θ of the quadrupole magnetic field generator 8 is 0 ° <θ <90 ° or 90 ° <θ <180 °.
By limiting to either of the above, the resolution improvement effect by the centralized correction of the outer electron beam can be strengthened for one or both of the central electron gun and the outer electron gun, and the conventional quadrupole magnetic field generator can be used. In this case, the difference in focus characteristics between the central electron gun and the outer electron gun that would otherwise occur can be reduced.

As described above, the vertical length ratio of the electron beam spot is not suitable as an index of the focus characteristic of the electron gun. In the first place, the phenomenon that the electron beam spot becomes vertically long at the center of the scanning screen is synonymous with the fact that the focal point positions are different in the X and Y axis directions of the electron beam, that is, the electron beam has astigmatism. Therefore, it is appropriate to express the amount of astigmatism as an index of the focus characteristic, and this is defined as the aberration coefficient as described above.
The larger the aberration coefficient, the larger the amount of astigmatism in the direction of improving the deflection aberration and the halo around the scanning screen.

Further, in order to have the amount of astigmatism that improves the deflection aberration and the halo, the aberration coefficient must have a positive value from its definition. The index of the aberration coefficient can be used not only when the electron beam spot at the center of the scanning screen is vertically long, but also when the electron beam spot is not vertically long by various resolution improving measures.

In the in-line type color cathode ray tube 1 in which the outer electron beams 11r and 11b are insufficiently concentrated, the electron beam spot at the center of the scanning screen is vertically elongated by the concentration correction by the quadrupole magnetic field generator. For example, the concentration correction is to increase the aberration coefficient of the electron gun. The focus difference between the central electron gun and the outer electron gun, which is likely to occur in the conventional quadrupole magnetic field generator 8c, is no different from the difference in the aberration coefficient between them.

Therefore, in the in-line type color cathode ray tube 1 of the above-mentioned embodiment, when the conventional quadrupole magnetic field generator 8c is used to perform the concentrated correction of the outer electron beams 11r and 11b, the aberration coefficient of the outer electron is larger than that of the central electron gun. When the size is reduced by the gun, the quadrupole magnetic field generator 8 of this embodiment is used to set the adjustment angle θ to 90 ° <θ <180 ° and the outer electron beam 1
By performing the concentrated correction of 1r and 11b, the aberration coefficient of the outer electron gun can be increased, and as a result, the difference in the aberration coefficient between the central electron gun and the outer electron gun is reduced, that is, the focus difference is reduced.

On the contrary, if the central electron gun has a smaller aberration coefficient than the outer electron gun when the outer electron beams 11r and 11b are concentratedly corrected by using the conventional quadrupole magnetic field generator 8c, the present embodiment is performed. Using the quadrupole magnetic field generator 8 of the example, the adjustment angle θ is set to 0 ° <θ <90 ° and the outer electron beam 11
By performing the concentrated correction of r and 11b, the aberration coefficient of the central electron gun can be increased, and thus the focus difference similarly decreases. 3 (a) and 3 (b), a conventional quadrupole magnetic field generator when a 16-inch in-line type color cathode ray tube is operated under conditions of a high voltage of 25 kv and a cathode current of 0.3 mA per single electron gun. 8c and aberration coefficients when the outer electron beam is concentrated and corrected using the quadrupole magnetic field generator 8 of the present embodiment.

The aberration coefficient needs to have a positive value in order to improve the deflection aberration and halo around the scanning screen, but if the aberration coefficient is too large, the electron beam spot at the center of the scanning screen becomes excessive. It becomes vertically long and the resolution at the center of the scanning screen deteriorates. According to the experimental results, it is suitable that the range of the aberration coefficient that makes the resolution of the entire scanning screen good and well-balanced is 0 to 300 v.

FIG. 4 shows electron beam spot diameters at the center and the periphery of the scanning screen when a 20-inch in-line type color cathode ray tube is operated under the conditions of a high voltage of 26 Kv and a cathode current of 0.3 mA per single electron gun. The relationship of an aberration coefficient is shown. As can be seen from this figure, when the aberration coefficient is negative, the electron beam spot diameter around the scanning screen suddenly increases, and conversely, when the aberration coefficient exceeds 300 v, the electron beam spot diameter at the center of the scanning screen increases. Too much.

Example 2. In the first embodiment, the quadrupole magnetic field generator 8 is composed of a pair of annular magnets 8a and 8b.
As shown in FIG. 3, a strip member 8f made of a low magnetic material is provided around the neck 6, and the outer electron beam 11r,
The same effect can be obtained by using a quadrupole magnetic field generator 8g which is configured to form a permanent magnetic region having a magnetism corresponding to the insufficient concentrated amount of 11b and a magnetic pole strength.

Example 3. Although the first and second embodiments have been described with a focus on reducing the focus difference between the central electron gun and the outer electron gun of the in-line type electron gun assembly 7, the present invention may intentionally provide the focus difference. Is.
That is, in the in-line type color cathode ray tube 1 in which the outer electron beams 11r and 11b are insufficiently concentrated,
Using the conventional quadrupole magnetic field generator 8c, the outer electron beam 11
Even when the central electron gun and the outer electron gun have substantially the same aberration coefficient when r and 11b are collectively corrected, that is, the focus difference is small, for example, the quadrupole magnetic field generator 8 described in the first embodiment is used.
If the adjustment angle θ is set to 90 ° <θ <180 ° and the outer electron beams 11r and 11b are concentratedly corrected, the aberration coefficient of the outer electron gun can be made larger than that of the central electron gun.

In general, the deflection aberration and halo around the scanning screen are stronger in the outer electron gun than in the central electron gun. Therefore, it may be desirable to intentionally increase the aberration coefficient of the outer electron gun in this way. In any case, the present invention is effective.

[0038]

As described above, according to the first aspect of the present invention, the in-line type color cathode ray line having the in-line type electron gun structure is set so that the outer electron beam is insufficiently concentrated with respect to the central electron beam. The quadrupole magnetic field generator used for the concentrated correction of the tube has a first annular magnet formed so that two N poles face inward at an angular interval of 180 °, and also two S poles. Is composed of a second annular magnet formed to face inward with an angular interval of 180 °, the resolution of the electron gun due to the concentrated correction when the outer electron beam is concentratedly corrected. There is an effect that the improvement effect can be enhanced by either the central electron gun or the outer electron gun.

According to the second aspect of the present invention, as the index of the focus characteristic of the electron gun, the focusing voltage that minimizes the lateral diameter of the electron beam spot at the center of the phosphor screen is changed to the focusing voltage that minimizes the longitudinal diameter. When the voltage value obtained by subtracting is defined as the aberration coefficient, if the aberration coefficient of the outer electron gun becomes smaller than that of the central electron gun when the outer electron beam is concentratedly corrected by the conventional quadrupole magnetic field generator, The outer electron beam is concentrated and corrected within the range of 90 ° <θ <180 ° in the adjustment angle θ of the quadrupole magnetic field generator of item 1, and conversely, the outer electron beam is concentrated by the conventional quadrupole magnetic field generator. When the aberration coefficient is smaller in the central electron gun than in the outer electron gun when corrected, the adjustment angle θ of the quadrupole magnetic field generator of claim 1 is 0 ° <θ.
The outer electron beam is concentratedly corrected within the range of <90 °, and the aberration coefficient of each electron gun is set in the range of 0 to 300 v. Therefore, while the effect of improving the resolution of the electron gun by the concentration correction remains, In this quadrupole magnetic field generator, it is possible to reduce the focus characteristic difference between the central electron gun and the outer electron gun, and suppress the vertical overshoot of the electron beam spot in the center of the scanning screen and the deflection aberration and halo around the scanning screen. There is an effect that the resolution of the entire scanning screen can be well balanced and good.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an in-line type color cathode ray tube according to an embodiment of the present invention and an exploded perspective view showing a configuration of a quadrupole magnetic field generator according to this embodiment.

FIG. 2 is a cross-sectional view of a portion attached to a neck for explaining the operation of the quadrupole magnetic field generator of this embodiment.

FIG. 3 is a diagram showing experimental data showing the relationship between the quadrupole magnetic field generator of this example and the aberration coefficient.

FIG. 4 is a diagram showing experimental data showing the relationship between the aberration coefficient and the electron beam spot diameter in this example.

FIG. 5 is a sectional view of a portion in which a quadrupole magnetic field generator according to another embodiment of the present invention is attached to a neck.

FIG. 6 is a cross-sectional view showing a configuration of a conventional in-line type color cathode ray tube and an exploded perspective view showing a configuration of the conventional quadrupole magnetic field generator.

FIG. 7 is a cross-sectional view of a portion attached to a neck for explaining the operation of a conventional quadrupole magnetic field generator.

FIG. 8 is a schematic diagram showing the shape of an electron beam spot on a scanning screen.

[Explanation of symbols]

 1 In-line type color cathode ray tube 2 Phosphor screen 3 Panel 6 Neck 7 In-line type electron gun structure 8 4-pole magnetic field generator 8a, 8b Annular magnet 25, 26 N-pole magnet 27, 28 S-pole magneton

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] January 10, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

That is, one of the outer electron gun and the central electron gun has an electron beam spot as shown in FIG.
No. 29 is vertically long at the center of the scanning screen, but deflection distortion and halo are good at the periphery of the scanning screen . On the other hand, as shown in FIG. 8B, the electron beam spot 29 is almost at the center of the scanning screen. Although it is a perfect circle, there is a problem that deflection distortion and halo 30 are large around the scanning screen, making it difficult to compromise the focus characteristics among the electron guns.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

The present invention has been made in order to solve the above-mentioned problems, and the outer electron gun and the central electron generated during the concentrated correction are left while the resolution improving effect of the concentrated correction by the conventional quadrupole magnetic field generator is left. It is an object of the present invention to obtain a quadrupole magnetic field generator capable of reducing the focus characteristic difference between guns, and to obtain a convergence adjustment method using this quadrupole magnetic field generator.

Claims (2)

[Claims] 1. A quadrupole which is mounted on a neck portion of a color cathode line equipped with an in-line type electron gun structure configured so that an electron beam is concentrated on a panel side with respect to a center of a phosphor screen and corrects the concentration characteristic. A quadrupole magnetic field generator for generating a magnetic field, wherein a first annular magnet in which two N poles are formed so as to face inward at an angular interval of 180 °, and two S poles are 180 A quadrupole magnetic field generator comprising a second annular magnet formed to face inward at an angular interval of °. 2. The focusing voltage of the electron gun assembly in which the lateral diameter of the electron beam spot in the center of the phosphor screen in the electron gun array direction is minimized when the quadrupole magnetic field generator according to claim 1 is used for concentrated adjustment. Therefore, when the value obtained by subtracting the focusing voltage that minimizes the longitudinal diameter of the electron beam is used as the aberration coefficient, the aberration coefficient of each electron gun is set to be in the range of 0 to 300 V, and at the same time, the conventional 90 ° When the quadrupole magnetic field generator in which the N poles and the S poles are alternately formed at angular intervals is used to correct the outer electron beam so that it is concentrated in the center of the phosphor screen, the aberration coefficient of the outer electron gun is the center electron. When it is smaller than the aberration coefficient of the gun, the adjustment angle θ of the quadrupole magnetic field generator according to claim 1
Is adjusted within the range of 90 ° <θ <180 °,
On the contrary, when the aberration coefficient of the outer electron gun is larger than that of the central electron gun, the adjustment angle θ is 0 ° <θ <90 °.
Centralized adjustment method characterized by adjusting to be within the range of.