JP2002056788A - Electron gun for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electron gun for a cathode-ray tube which can raise degree of freedom of a design and can secure hardness of an electrode. SOLUTION: The electron gun 10 for cathode-ray tubes is constituted so that both of holes in which electron beam passes, of opposite electrodes 15A, 15B may have an oblong astigmatic shape, in the electrodes 15A, 15B which constitute four-fold electrode lens QL2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun for a cathode ray tube having electrodes constituting a quadrupole lens.

[0002]

2. Description of the Related Art In a color cathode ray tube, a demand for a high definition cathode ray tube has been increasing.
High accuracy is also required for electron guns.

For this reason, a quadrupole lens has been formed in an electron gun in order to correct the deflection distortion at the peripheral portion of the screen.

[0004] As an electrode constituting a quadrupole lens, an electrode having a rectangular or eave-shaped electron beam passage hole is used. FIG. 9 shows a case where a quadrupole lens is formed by making rectangular electron beam passage holes face each other. The electrode 101 on the cathode (cathode) side is formed with a vertically long (V1> H1) rectangular electron beam passage hole 101A. The electrode 102 on the anode side has a horizontally long (V2 <H2) rectangular electron beam passage hole 102A. A quadrupole lens can be formed by making the vertically elongated rectangular electron beam passage hole 101A and the horizontally elongated rectangular electron beam passage hole 102A face each other. In this case, V1 / H1> V2 / H2.

FIG. 10 shows a case where a quadrupole lens is formed using an eaves-shaped electron beam passage hole. In this case, the electrode 112 on the anode side has an electron beam passage hole 112A provided with eaves 112B vertically. The electrode 111 on the cathode (cathode) side is formed with an I-shaped electron beam passage hole 111A having an opening 111B into which an eave 112B enters. By making these electron beam passage holes 111A and 112A face each other, a quadrupole lens can be formed.

In addition, a configuration in which eaves are provided in both opposing electron beam passage holes, and a configuration in which a rectangular electron beam passage hole and an electron beam passage hole provided with an eave are opposed to each other are also possible.

Here, an example of an electron gun incorporating the configuration of the electrode shown in FIG. 10 is shown in FIG. 11 and FIG. FIG.
FIG. 2 is a perspective view in which essential parts of each electrode such as an electron beam passage hole are extracted. FIG. 12 is a block diagram showing the configuration of the electrode.

This electron gun has red, in-line arrangement,
Three cathodes K corresponding to green and blue (KR, KG, K
B) and a plurality of electrodes, that is, the first electrode 11 and the second electrode 1 so as to be common to the cathodes KR, KG, and KB.
2, third electrode 13, fourth electrode 14, fifth electrode 15, sixth electrode
It has an electrode 16. The third electrode 13 is divided into a third A electrode 13A on the cathode K side and a third B electrode 13B on the anode side. The fifth electrode 15 is divided into a fifth A electrode 15A on the cathode K side and a fifth B electrode 15B on the anode side. A shield cup 20 integral with the sixth electrode 16 is provided at a subsequent stage. Also, the fifth B electrode 15B and the sixth electrode 16 constituting the main lens ML
And an intermediate electrode 17 (GM).

The second electrode 12 and the fourth electrode 14 are electrically connected, and are supplied with the same voltage. Third B electrode 1
For example, a fixed focus voltage is supplied to the 3B and fifth A electrodes 15A as the first focus voltage Ef1. The third A electrode 13A and the fifth B electrode 15B have the second
For example, a dynamic focus voltage is supplied as the focus voltage Ef2.

Then, as shown in FIG. 11, a first quadrupole lens QL1 is constituted by the third A electrode 13A and the third B electrode 13B. The electron beam passage hole of the third A electrode 13A is I-shaped, and the electron beam passage hole of the third B electrode 13B is provided with eaves above and below the circular hole. Further, the cathodes K of the fifth A electrode 15A and the fifth B electrode 15B
The second surface 51 forms a second quadrupole lens QL2. The electron beam passage hole of the fifth A electrode 15A has an I-shape, and the electron beam passage hole of the cathode K side surface 51 of the fifth B electrode 15B is provided with eaves above and below the rectangular hole. That is, the two electrodes 111 and 112 shown in FIG. 10 constitute the second quadrupole lens QL2.

By providing the quadrupole lenses QL1 and QL2 in this manner, a quadrupole, that is, an electrostatic quadrupole is formed by an electric field generated by the electrodes constituting the quadrupole lenses QL1 and QL2. Can be corrected, and the deflection aberration can be corrected.

[0012]

In FIG. 9, the width B of the so-called blitch between the horizontally long electron beam passage holes 102A, which connects the upper and lower portions, is narrow.
In FIG. 10, an eave-shaped electron beam passage hole 1 is shown.
In 12A, a margin is provided beside the eaves 112B in order to form the eaves 112B by bending the member, and the width B of the blitch becomes narrower as the width of the electron beam passage hole 112A becomes wider. When the width B of the blitch is reduced in this way, the strength of the parts is insufficient and the parts are easily deformed.

Further, in order to secure sufficient strength in this blitch, design restrictions are imposed on the size of the electron beam passage hole and the like. Therefore, 4 formed by the electrodes
Attempts to optimize the dipole lens may not be possible due to design constraints.

In order to solve the above-mentioned problems, the present invention provides an electron gun for a cathode ray tube, which can secure sufficient strength of electrodes and can improve design flexibility.

[0015]

In the electron gun for a cathode ray tube according to the present invention, in the electrodes constituting the quadrupole lens, the electron beam passage holes of the opposing electrodes are both vertically elongated astigmatic shapes. .

According to the configuration of the present invention described above, since the electron beam passage holes of the electrodes facing the electrodes constituting the quadrupole lens are both vertically elongated astigmatic shapes, the lateral width of the electron beam passage holes is reduced. And the width of a portion (blitch portion) between the electron beam passage holes can be increased.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is an electron gun for a cathode ray tube in which electrodes forming a quadrupole lens have electron beams passing holes of the opposing electrodes in a vertically long astigmatic shape.

FIG. 1 is a perspective view showing the essential parts of each electrode of an electron gun for a color cathode ray tube according to an embodiment of the present invention.
FIG. 2 shows a block diagram of the electron gun for a color cathode ray tube of FIG. The electron gun 10 for a color cathode ray tube has three cathodes K (K) corresponding to red, green and blue, which are arranged in-line.
R, KG, KB) and a plurality of electrodes, that is, a first electrode 11,
It has a second electrode 12, a third electrode 13, a fourth electrode 14, a fifth electrode 15, and a sixth electrode 16. The third electrode 13 is divided into a third A electrode 13A on the cathode K side and a third B electrode 13B on the anode side. The fifth electrode 15 is divided into a fifth A electrode 15A on the cathode K side and a fifth B electrode 15B on the anode side. A shield cup 20 integral with the sixth electrode 16 is provided at a subsequent stage. Further, an intermediate electrode 17 (GM) is provided between the fifth B electrode 15B and the sixth electrode 16 constituting the main lens ML.

The second electrode 12 and the fourth electrode 14 are electrically connected, and are supplied with the same voltage. Third B electrode 1
For example, a fixed focus voltage is supplied to the 3B and fifth A electrodes 15A as the first focus voltage Ef1. The third A electrode 13A and the fifth B electrode 15B have the second
For example, a dynamic focus voltage is supplied as the focus voltage Ef2. Although not shown, an intermediate voltage between the anode voltage and the focus voltage is supplied to the intermediate electrode 17 (GM).

The first quadrupole lens QL1 is constituted by the third A electrode 13A and the third B electrode 13B. FIG.
Similarly to the electron gun described above, the electron beam passage hole of the third A electrode 13A is I-shaped, and the electron beam passage hole of the third B electrode 13B is provided with eaves above and below the circular hole.

The fifth A electrode 15A and the fifth B electrode 15
The surface 51 on the cathode K side of B constitutes a second quadrupole lens QL2. In the present embodiment, the electron beam passage hole of the fifth A electrode 15A is a vertically long rectangle, and the
The electron beam passage hole in the surface 51 on the cathode K side of the electrode 15B is also a vertically long rectangle. That is, the fifth A electrode 15A and the fifth B
Each electron beam passage hole in the cathode-side surface 51 of the electrode 15B is a vertically long rectangle. However, as shown in FIG. 1, the electron beam passage hole of the fifth A electrode 15A has a large aspect ratio, while the electron beam passage hole of the fifth B electrode 15B has a small aspect ratio.

By providing the quadrupole lenses QL1 and QL2 in this manner, a quadrupole, that is, an electrostatic quadrupole is formed by an electric field generated by the electrodes constituting the quadrupole lenses QL1 and QL2. Can be corrected, and the deflection aberration can be corrected.

Each of the electrodes 15B, 17 and 16 constituting the main lens ML has a total of three electron beams of a large elliptical electron beam passage hole on both outer sides and a small elliptical electron beam passage hole at the center. Electrode plates 52, 72, and 62 provided with through holes are provided.

Here, the electron gun 1 for a color cathode ray tube shown in FIG.
5A constituting the second quadrupole lens QL2 at 0
The surface 51 on the cathode K side of the electrode 15A and the fifth B electrode 15B
FIG. 3 shows an enlarged view of a main part of the electrode. Electrode 31 on the cathode side, that is, electron beam passage hole 31 of fifth A electrode 15A
A is a vertically long rectangular shape, and V1> H1. The electrode 32 on the anode side, that is, the electron beam passage hole 32A on the surface 51 on the cathode side of the fifth B electrode 15B is also a vertically long rectangular shape, and V2>
H2.

The electron beam passage hole 31A of the electrode 31 on the cathode side has a larger aspect ratio than the electron beam passage hole 32A of the electrode 32 on the anode side. That is, V1 /
H1> V2 / H2> 1 holds.

As described above, in the two electrodes 31 (15A) and 32 (51) constituting the quadrupole lens, the electron beam passage holes 31A and 32A of the opposing electrodes are each formed into a vertically long astigmatic shape. And the width B of the blitch portion can be increased. In particular, the width of the anode side electrode 32 (51), in which the width B of the blitch portion was narrow in the past, is considerably wider than in the past. As described above, since the width B of the blitch portion is increased, the strength of the electrode can be increased.

The electron beam passage holes 31 of the opposing electrodes
A and 31B both have a vertically long astigmatic shape, which is compared with the case where the vertically long astigmatic electron beam passing hole and the horizontally long astigmatic electron beam passing hole are opposed as shown in FIG. The direct astigmatism effect is reduced. In this regard, the quadrupole lens effect equivalent to the conventional one can be obtained by adjusting the aspect ratio of the electron beam passage holes 31A and 31B, the interval between the opposing electrodes 15A and 51, and the magnitude of the voltage supplied to the electrodes. It is possible to get. Therefore, the same function as that of the related art can be realized even when the width of the rich portion is wider than that of the related art.

Also, the electrode 15 constituting the quadrupole lens
If the size of the electron beam passage holes of A and 51 is made extremely small, aberration due to the quadrupole lens increases. For this reason, the size of the electron beam passage hole should be at least a certain size so as to reduce the influence of the aberration.

Here, the strength when the width B of the blitch portion of the electrode was actually changed was examined. A load of 3 kg weight was applied to the center of the blitch portion perpendicularly to the electrode surface, and the amount of deformation of the blitch portion was measured. The width B of the blitch portion is 1.2 mm and 1.
The measurement was performed as two types of 7 mm.

As a result, the width B of the blitch portion is set to 1.2 mm
It was found that when the magnification was increased by about 1.5 times from 1.7 to 1.7 mm, the deformation amount was reduced from about 400 μm to about 200 μm to about 1/2, and the strength was improved.

According to the above-described embodiment, since the electron beam passage holes 31A and 31B of the opposing electrodes are formed in a vertically long astigmatic shape, the width B of the rich portion can be increased. The strength of the electrode can be improved.

Therefore, although the size of the electron beam passage hole is limited in design in order to secure the strength, the limitation is relaxed and the degree of freedom in design is improved. This also allows the electrodes to be designed to further optimize the lens effect of the quadrupole lens.

By the way, in a color cathode ray tube for a display or a TV receiver, demands for high definition, high brightness and low driving voltage are increasing. In recent years, in order to achieve higher definition, it has been attempted to reduce the spot size by reducing the diameter of the electron beam passage holes of the first electrode and the second electrode using a conventional electron gun. However, if the diameters of the electron beam passage holes of the first and second electrodes are reduced, a sufficient amount of current (intensity of the electron beam) must be ensured so that the luminance required for display can be obtained. Need to be larger. When the drive voltage increases, a problem arises in that high-frequency driving deteriorates signal followability and makes display difficult.

In order to reduce the spot size by reducing the diameter of the electron beam passage holes in the first and second electrodes without increasing the drive voltage, a so-called multiple beam electron gun has been proposed. In the conventional electron gun, one electron beam passage hole is formed for one cathode.
A plurality of, for example, two electron beam passage holes are formed for each.

When a quadrupole lens is further formed in the multiple-beam electron gun, a quadrupole lens function for correcting deflection distortion and a lens for converging a plurality of beams emitted from one cathode are provided. There is a demand for a quadrupole lens that simultaneously realizes the function and has no compound function.

For example, when a multi-beam electron gun that emits two electron beams in a horizontal direction from one cathode is applied to an electron gun for a color cathode ray tube, a total of six electron beams exist in the horizontal direction. 4 for these 6 electron beams
In order to achieve the effect of the dipole lens, six electron beam passage holes are required independently for each electron beam.

However, when applying the quadrupole lens having the electrode configuration shown in FIGS. 9 and 10 to a multiple beam electron gun, for example, the width of the electron beam passage holes 102A and 112A provided with horizontally long rectangles or eaves is required. Is large,
It is difficult to form six electron beam passage holes in a horizontal direction.

Therefore, the present invention is applied to construct a quadrupole lens in a multiple beam electron gun. An embodiment in this case will be described below. FIG. 4 is a perspective view of a main part of each electrode of a color cathode ray tube electron gun according to another embodiment of the present invention. The electron gun 30 for a color cathode ray tube has three cathodes K (K) corresponding to red, green and blue arranged in line.
R, KG, KB) and a plurality of electrodes, that is, a first electrode 11,
It has a second electrode 12, a third electrode 13, a fourth electrode 14, a fifth electrode 15, and a sixth electrode 16.

The fifth electrode 15 is divided into a fifth A electrode 15A on the cathode K side and a fifth B electrode 15B on the anode side. A shield cup 20 integral with the sixth electrode 16 is provided at a subsequent stage. Also, the main lens M
An intermediate electrode 17 (GM) is provided between the fifth B electrode 15B and the sixth electrode 16 constituting L.

The first electrode 11 and the second electrode 12 are formed with a total of six small circular electron beam passage holes, two for each of the cathodes KR, KG, and KB. On the surface 131 of the third electrode 13 on the cathode K side, three circular electron beam passage holes are formed.

Since two electron beam passage holes are formed for each of the cathodes KR, KG, and KB, two electron beams can be emitted from one cathode.

The quadrupole lens QL is constituted by the surface 152 on the anode side of the fifth A electrode 15A and the surface 153 on the cathode K side of the fifth B electrode 15B. In the present embodiment, the electron beam passage holes on the anode side surface 152 of the 5A electrode 15A are vertically long rectangles, and the electron beam passage holes on the cathode K side surface 153 of the 5B electrode 15B are also vertically long rectangles. . That is, each electron beam passage hole is a vertically long rectangle. However, as shown in FIG. 4, the electron beam passage hole on the anode side surface 152 of the 5A electrode 15A has a large aspect ratio, while the electron beam passage hole on the cathode K side surface 153 of the 5B electrode 15B. Has a small aspect ratio.

Each of the electrodes 15B, 17, 16 constituting the main lens ML has an electrode plate 15 having six elliptical electron beam passage holes arranged in line.
4, 172, 162 are provided.

On the anode-side surface 132 of the third electrode 13 and the cathode-side surface 151 of the 5A-th electrode, a total of four electron beam passage holes, two circular and two elliptical, are formed. Six circular electron beam passage holes are formed in the fourth electrode 14 therebetween. And these third electrodes 1
3, the anode-side surface 132, the fourth electrode 14, and the cathode-side surface 151 of the 5A-th electrode form the orbit correction lens CL.
Is composed.

The trajectory correcting lens CL includes the first electrode 11
The trajectory is provided so that the electron beam passing through the second electrode 12 passes through the electron beam passage hole of the quadrupole lens QL or the main lens ML. The trajectory correction lens CL causes the electron beam to be shifted by two for each cathode at the first electrode 11 and the second electrode 12, but the electron beam is incident on the quadrupole lens QL. It is corrected to a state close to the interval.

Here, the electron gun 3 for a color cathode ray tube shown in FIG.
5A electrode 15 constituting the quadrupole lens QL at 0
FIG. 5 is an enlarged view of an essential part of the electrode of the surface 152 on the anode side of A and the surface 153 on the cathode K side of the fifth B electrode 15B.
Shown in The electron beam passage hole 152A on the anode-side surface 152 of the fifth A electrode 15A has a vertically long rectangular shape.
The electron beam passage hole 153 in the cathode side surface 153 of the B electrode 15B is also a vertically long rectangular shape. The aspect ratio of the electron beam passage hole 152A on the surface 152 on the cathode side is larger than that of the electron beam passage hole 153A on the surface 153 on the anode side.

As described above, in the two electrodes 152 and 153 constituting the quadrupole lens, the electron beam passage holes 152A and 153A of the opposing electrodes are both formed in a vertically long astigmatic shape. Compared with the case where the astigmatic shape or the eaves are provided, the blitch portion can be made wider. In particular, in this embodiment, the electron beam passage hole 15 is used.
Although two 2A and 153A are formed in an in-line arrangement, the strength of the electrodes 152 and 153 can be ensured because the blitch portion can be widened. Therefore, an electrode provided with six electron beam passage holes arranged in line can be realized.

In the electron gun 30 for a color cathode ray tube according to the present embodiment, the quadrupole component, that is, the astigmatism of the electron beam is reduced by the above-described configuration, so that the electron beam passage holes 152A, It can be adjusted at an aspect ratio of 153A, and the convergence of two electron beams emitted from one cathode can be adjusted by the horizontal distance between electron beam passage holes through which the two electron beams pass.

Further, since there is no interaction between the astigmatism and the convergence, the electron beam passage holes 152 of the electrodes 152 and 153 constituting the quadrupole lens QL are formed.
By changing the size and shape of A and 153A, they can be adjusted independently.

A simulation was performed to confirm this effect. FIG. 6 is a perspective view of the electrodes constituting the quadrupole lens of the model used for the simulation. Two vertically elongated electron beam passage holes 81A and 82A are formed in the anode 81 and the cathode 82, respectively.
The illustrated two electron beam passage holes 81A, 81A and 82A, 82A are for the passage of two electron beams emitted from the same cathode of a multiple beam electron gun.

As the index, the astigmatism and the direction of the electron beam shown in FIG. 7 were employed. As shown in FIG. 7A, the circular electron beam EB1 before passing through the quadrupole lens is
The electron beam EB2 after being deformed by passing through the dipole lens
, The ratio V / H of the vertical length V to the horizontal length H is defined as astigmatism. That is, the astigmatism = 1 in the original circular electron beam EB1. As shown in FIG. 7B, two electron beams (hereinafter, referred to as small beams) SB1 and SB2 emitted from the same cathode pass through an extension line parallel to the central axis (Z direction) and the quadrupole lens QL. The direction of the trajectory of the small beam is indicated by an angle θc formed with the trajectory after the movement. In the figure, θc is a positive value (divergence direction), but can take a value of 0 ° (same as the trajectory before passing through the quadrupole lens QL) or a negative value (convergence direction).

Then, assuming that all other conditions are the same,
Regarding the electron beam passage hole 81A of the electrode 81 on the cathode side,
Its horizontal dimension H1 and pitch (horizontal distance between the center axis of the electron beam of each color and the center of the electron beam passage hole) P
1. The vertical dimension V2, the pitch P2, and the horizontal dimension H2 of the electron beam passage hole 82A of the anode-side electrode 82 are respectively changed to obtain the astigmatism (V / H) and θc.
(゜) was obtained. The thickness D of the electrode is 0.5 mm
The electrode 81 on the cathode side has 5 kV and the electrode 8 on the anode side
The calculation was performed assuming that each voltage of 6 kV was supplied to 2.
FIG. 8 shows the results. A mark indicates astigmatism, and a mark indicates θc.

The following can be seen from FIG. By changing the interval between the two electron beam passage holes of each color, the pitches P1, P
When 2 is changed, the change of the trajectory (θc) of the electron beam is large, but the effect of astigmatism (the degree of astigmatism V / H) does not change much. On the other hand, dimensions H1, V2, H2 of the electron beam passage holes
Changes the trajectory of the electron beam.
The effect of astigmatism changes greatly. The same applies to V1 not shown. Therefore, the stigmatic effect and the correction of the trajectory of the electron beam can be independently performed by respectively changing the interval and the size of the electron beam passage holes.

According to the above-described embodiment, since the electron beam passage holes 152A and 153A of the electrodes 152 and 153 constituting the quadrupole lens QL are both vertically long rectangles, the blit portion is widened. be able to. This allows a sufficient space, so that it is feasible to arrange six electron beam passage holes 152A and 153A in an in-line arrangement.

That is, also in the multiple beam electron gun, a quadrupole lens satisfying the same performance as the quadrupole lens of the conventional electron gun can be formed, and the strength of the electrode can be improved. Therefore, the characteristics of the color cathode ray tube can be improved.

According to the present embodiment, adjustment of the quadrupole component of the small beam (adjustment of astigmatism) and adjustment of the convergence of two small beams of the same color (orbit adjustment)
Can be independently adjusted by changing the design of the electrodes 152 and 153 constituting the quadrupole lens QL without receiving any interaction.

In the present embodiment, a multiple-beam electron gun that emits two electron beams per cathode can be formed, so that the size of the electron beam passage holes in the first electrode and the second electrode and the drive Under the same voltage condition, the current amount can be increased to twice that of the single beam electron gun. Thus, by reducing the electron beam passage holes of the first electrode 11 and the second electrode 12, it is possible to compensate for the decrease in the current amount of one electron beam by that amount, so that the drive voltage is not increased. However, the amount of current required for display can be secured.

Therefore, the spot size of the electron beam can be reduced by reducing the electron beam passage holes of the first electrode 11 and the second electrode 12. At this time, since the drive voltage is not increased, the followability of signals in high-frequency driving is improved. That is, it is possible to form a cathode ray tube having high definition, high brightness, and high resolution, and a high quality image can be obtained with the cathode ray tube.

In each of the above embodiments, the present invention is applied to an electron gun for a color cathode ray tube. However, the present invention can be applied to an electron gun for a cathode ray tube having another configuration. In a cathode ray tube in which an electron gun generates a plurality of electron beams, such as a color cathode ray tube, the above-described blitch portion is formed on an electrode constituting a quadrupole lens of the electron gun.
The present invention has a remarkable effect. Therefore, for example, in the case of an electron gun for a monochromatic cathode ray tube, a configuration in which a plurality of electron beams are emitted from the cathode and a case where the electron gun has a quadrupole lens formed by electrodes are similarly applied by applying the present invention. Has a remarkable effect.

Further, in each of the above-described embodiments, the electron beam passage holes of the electrodes constituting the quadrupole lens are all vertically long rectangular electron beam passage holes. Has the same effect. For example, the shape may be a vertically long ellipse or a shape in which four corners of a rectangle are rounded.

The present invention is not limited to the above-described embodiment, but may take various other configurations without departing from the gist of the present invention.

[0062]

According to the present invention described above, the width of the portion (blitch portion) between the electron beam passage holes can be increased by forming the electron beam passage holes in a vertically long astigmatic shape. In addition, the strength of the electrodes constituting the quadrupole lens can be improved.

In addition, since the design constraint for securing the strength is relaxed, the degree of freedom in design is improved. This also makes it possible to design the electrodes to optimize the lens effect of the quadrupole lens.

Therefore, according to the present invention, the strength of the electrode can be sufficiently ensured, and the degree of freedom in designing the electrode can be increased. Further, for example, a quadrupole lens using electrodes can be realized for a multiple-beam electron gun, similarly to a single-beam electron gun.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of each electrode of an electron gun for a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a block diagram of the color cathode ray tube electron gun of FIG.

FIG. 3 is an enlarged view of a main part of an electrode constituting a second quadrupole lens in the electron gun for a color cathode ray tube of FIG. 1;

FIG. 4 is a perspective view of a main part of each electrode of an electron gun for a color cathode ray tube according to another embodiment of the present invention.

5 is an enlarged view of a main part of an electrode constituting a quadrupole lens in the electron gun for a color cathode ray tube of FIG. 4;

FIG. 6 is a perspective view of electrodes constituting a quadrupole lens of a model used in the simulation.

FIG. 7 is a diagram illustrating indices used in the simulation. A is a diagram for explaining the astigmatism. B is a diagram illustrating the directions of the orbits of two small beams.

FIG. 8 is a diagram showing a result of a simulation.

FIG. 9 is a perspective view showing one configuration of an electrode constituting a conventional quadrupole lens.

FIG. 10 is a perspective view showing another configuration of the electrodes constituting the conventional quadrupole lens.

FIG. 11 is a perspective view in which main parts of each electrode of the electron gun incorporating the electrode configuration shown in FIG. 10 are extracted.

FIG. 12 is a block diagram showing a configuration of an electrode of an electron gun incorporating the configuration of the electrode shown in FIG. 10;

[Explanation of symbols]

10, 30 Electron gun for color cathode ray tube, 11 first electrode, 12 second electrode, 13 third electrode, 13A 3A electrode, 13B 3B electrode, 14 fourth electrode, 15th electrode, 15A 5A electrode, 15B 5B electrode, 16
6th electrode, 17 intermediate electrodes, 20 shield cups, 3
1,32 electrodes, 31A, 31B electron beam passage holes,
K, KR, KG, KB cathode, QL1, QL2, Q
L quadrupole lens, ML main lens, CL orbit correction lens

Claims (1)

[Claims] 1. An electrode constituting a quadrupole lens,
An electron gun for a cathode ray tube, wherein both of the electron beam passing holes of the opposing electrodes have a vertically long astigmatic shape.