JPH02189842A - Electron gun for color image receiving tube - Google Patents

Abstract

PURPOSE:To provide high resolution over the whole area of a fluorescent screen, accomplish good convergence, and embody an electron gun for color image recieving tube with easiness to assemble electrode by adopting a main lens in a new electrode constitution according to the invention. CONSTITUTION:A 4-polar lens electric field is formed from parallel flat plate electrodes (vertical plate) 34-37, which pinch the electron beam penetrating hole in No.1 convergence electrode 30, and parallel fat plate electrodes (horizontal plate) 44, 45 pinching the electron beam penetrating hole in No.2 convergence electrode 40. The heights of the vertical plates 34-37 shall be such that the outside of the electron beam penetrating holes on both sides is higher than the inside, and an inclined electric field for correction of misconvergence of the side electron beam is formed between the outer vertical plate and inner vertical plate. The distance at this time of side electron beam penetrating holes 51, 53 from the axis C of electron gun is the same in all of a control electrode 10, an accelerating electrode 20, and convergence electrodes 30, 40, while the shaft separating distance of the penetrating holes 51, 53 from the axis C in the anode 50 shall be greater than in the electrode at the foregoing stage, and thus convergence of the side electron beam is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an electron gun for a color picture tube, which is equipped with an electron lens configuration that provides high resolution and good convergence characteristics over the entire area of the phosphor screen of the color picture tube. Regarding.

[Conventional technology]

The resolution of a picture tube largely depends on the electron beam spot diameter and its shape. That is, high resolution cannot be obtained unless the electron beam spot, which is a bright spot generated on the phosphor screen surface by the impact of the electron beam, has a small diameter and is close to a perfect circle.

However, the electron beam trajectory from the electron gun to the phosphor screen surface becomes longer as the deflection angle of the electron beam increases, so the electron beam spot has a small diameter and a perfect circle at the center of the phosphor screen surface. If the focus voltage is maintained at the optimum focus voltage that yields the phosphor screen surface, the periphery of the phosphor screen surface will be in an overfocus state, making it impossible to obtain a good electron beam spot and high resolution in the periphery.

Therefore, the so-called Guinamisoku focus method is used, which increases the focus voltage and weakens the main lens electric field as the deflection angle of the electron beam increases.As explained below, this method is an in-line type. Not suitable for driving color picture tubes.

In other words, in an in-line color picture tube in which three electron beam emitting sections are arranged in a straight line in the horizontal scanning direction, the horizontal deflection magnetic field distribution is shaped like a binktion, and the vertical deflection magnetic field distribution is shaped like a barrel, in order to obtain a self-convergence effect. Since each of these is distorted, the cross-sectional shape of the electron beam that passes through this is distorted into a non-circular shape.

Since the phosphor screen surface is usually horizontally elongated, that is, has a rectangular shape with long sides in the electron beam arrangement direction (horizontal direction), distortion becomes particularly large at the horizontal peripheral portion.

FIG. 3 is an explanatory diagram of the relationship between the quadrupole lens magnetic field and the electron beam, ], 2. 3 is an electron beam, and 4 is a horizontal deflection magnetic field.

FIG. 4 is an explanatory diagram of the relationship between the horizontal deflection magnetic field of the binction magnetic field distribution and the electron beam, and 6 is a dipole magnetic field component;
7 is a quadrupole magnetic field component, and 9 is an electron beam.

FIG. 5 is an explanatory diagram of shape distortion of the beam spot, 9
C is a beam spot at the center of the phosphor screen, 9H is a high brightness part (part of the core) of the electron beam at the periphery of the phosphor screen, and 9L is a low brightness part (haze part).

In FIG. 3, three electron beams 1, 2, and 3, which have been traveling from the back side of the paper, are deflected in the direction indicated by an arrow 5 by being incident on a horizontal deflection magnetic field 4 having a binction-like distribution. That is, the horizontal deflection magnetic field 4 with a binction-like distribution consists of a dipole magnetic field component 6 as shown in FIG. 4(a) and a quadrupole magnetic field component 7 as shown in FIG. 4(b). It can be considered that the dipole magnetic field component 6 exerts a deflection effect on the electron beam 9 in the direction shown by the arrow 8.

The quadrupole magnetic field component 7 gives a self-convergence effect to the three electron beams, but when looking at one electron beam 9, it gives a diverging effect in the horizontal direction and a focusing effect in the vertical direction. , the cross-sectional shape is horizontally long and flat.

By the way, the above-mentioned divergence effect acts in a direction that cancels out the overfocus of the electron beam spot due to the elongation of the electron beam trajectory as the electron beam deflection angle increases. Regarding direction, it is kept in optimal focus during the deflection period. However, in the vertical direction, the degree of overfocus increases significantly due to the addition of the focusing effect.

As a result, the electron beam spot generated at the center of the phosphor screen surface becomes circular as shown at 90 in FIG. 5(a), whereas the electron beam spot generated at the horizontal periphery is , as shown in FIG. 2(b), the non-circular distortion consisting of the high-brightness core part 9H and the low-brightness haze part 9L, and especially the large elongation of the haze part 9L in the vertical direction, deteriorates the focus characteristics. Don't let your shadow reach you.

In such a case, if the conventional Guinamisoku focus method is applied, this method weakens the lens action of the main lens equally regardless of the horizontal and vertical directions, so the haze portion 9L is removed in the vertical direction. However, the horizontal direction, which is already in optimum focus, becomes under-focused, and the diameter in the horizontal direction increases.

As a result, the electron beam spot becomes significantly horizontally long, and the resolution in the horizontal direction decreases.

Japanese Patent Laid-Open No. 63-32837 discloses a picture tube device that solves these problems and makes it possible to obtain high resolution over the entire area of the phosphor screen surface.

FIG. 6 is an explanatory diagram of the electron gun of the picture tube device disclosed in the above publication.

In the same figure, three cathodes 10a, 10b, 10c arranged horizontally and in a straight line are a control electrode 1]0, an acceleration electrode 120. First focusing electrode 130. Together with the second focusing electrode 140 and the final accelerating electrode (anode) 150, an in-line electron gun is configured.

The first focusing electrode 130 has three circular electron beam passing holes 130a and 130 on the end surface on the second focusing electrode 140 side.
b, 130c, and four mutually parallel vertical plate portions 131, 132, 133, and 134 protruding from the region sandwiching these electron beam passage holes. Further, the second focusing electrode 140 has three circular electron beam passing holes 141, 141° 143 on the end surface on the first focusing electrode 130 side, and two holes protruding from a region sandwiching these electron beam passing holes from the vertical direction. It has two mutually parallel horizontal plate parts 144, 145 for generating an electric field, and three circular electron beam passing holes 146, 1, 47 on the end face on the anode 150 side.
．． 14.8. Three circular electron beam passing holes 151, 152, 1, and 53 are formed in the end surface of the anode 150 on the second focusing electrode 140 side.
Three main lenses are created between the focusing electrode 140 and the anode 150.

Note that the control electrode 110 and the acceleration electrode] 20 each have three electron beam passing holes 111.11.2113.1.
21, 122, and 123, and three circular electron beam passing holes 13], , 132, and 133 are formed on the end face of the acceleration electrode 120 example of the first focusing electrode 130.

In the above configuration, the first focusing electrode 130 has a constant first
The focus voltage (VrC) is applied to the anode 150 at a constant high voltage (V3), and the second focusing electrode 140 is changed to a value higher than the first focus voltage (vrc) as the deflection angle of the electron beam increases. A voltage applying means for applying a dynamic voltage (V6) is provided.

As a result, when the horizontal deflection becomes zero, that is, when the first focusing electrode 130 and the second focusing electrode 140 both have the same potential, even if the electron beam passing hole of the picture electrode is vertically or horizontally long, these The shape has little effect on the electron beam. Then, the second focusing electrode 140 and the anode 15
0, three main lenses are generated, and three electron beams are focused at the center of the phosphor screen surface with optimum focus. When the horizontal deflection angle is increased, the potential of the second focusing electrode 140 becomes higher than the potential of the first focusing electrode 130, and the electric field generating vertical plate part 13 is formed between the electrodes.
1, 132, 133, 1.34, and the electric field generating horizontal plate portions 144, 145, a quadrupole electric field is generated. Also,
Since the potential difference between the second focusing electrode 140 and the anode 150 is reduced, the lens action of the main lens is weakened.

FIG. 7 is a simple explanatory diagram of the lens action due to the quadrupole electric field in FIG. 6, and shows the V8. Horizontal plate portion of second focusing electrode 140], 4.4. , 145 with the potential of V2, V, <V2
The quadrupole lens electric field generated between both electrodes under these conditions is as shown in the figure.

The equipotential lines forming the quadrupole lens electric field are potential vectors indicated by arrows 54.

Due to this quadrupole lens electric field, a force FvF++ that diverges in the vertical direction and converges in the horizontal direction acts on the electron beam 55, so that the electron beam 55 has a vertically elongated cross-sectional shape. This is the opposite of the electron beam that passes through the deflection magnetic field, which has a horizontally long cross-sectional shape due to the four components shown in FIG. It is possible to prevent horizontal flattening of the image.

In addition, as the deflection angle increases, the convergence effect of the main lens becomes weaker as described above, so overfocusing due to beam spot deflection can be prevented at the same time. It is also possible to generate a beam spot with a small diameter and nearly a perfect circle.

[Problem to be solved by the invention]

-fG, in a color picture tube electron gun, it is necessary to converge three electron beams to an image point on the phosphor screen surface.

Various techniques have been proposed for this convergence method, one of which is the electron beam trajectory of the electron beam passing hole between the focusing electrode that forms the final main lens and the side beam passing hole of the final accelerating electrode (anode). It is a method that does not shift the axis (off-cellar 1~), and the size of each electrode is located on the line connecting the three cathodes to the phosphor screen.The electron beam passage hole and the center electron beam passage This method changes the off-axis distance from the hole. The former method arranges the off-axis distances of the side electron beam passage holes and the center electron beam passage hole from the three cathodes to the focusing electrode on the same axis, and The center of the electron beam is eccentrically outward from the front electrode, and the center electron beam and the electron beam are made to coincide with each other on the phosphor screen.

With this method, the three electron guns from the cathode to the focusing electrode can be assembled using a coaxial jig when assembling the electrodes.
It is widely used as a structure that is suitable for mass production.

However, when this structure is applied to the electron gun described in JP-A-63-32837, the lens magnification with respect to the final accelerating electrode changes due to the application of a dynamic voltage to the second focusing electrode. The disadvantage is that the force that causes the site electron beam to converge changes, resulting in a shift in convergence.

On the other hand, when trying to apply the latter method to the electron gun described in JP-A-63-32837, since the electron beam orbital axis and the lens center of each electrode are on the same axis,
Even if a dynamic voltage is applied to the second focusing electrode, no convergence shift occurs, but because the off-axis distance between the site electron beam passing hole and the center electron beam passing hole of each electrode from the cathode to the final accelerating electrode is different, a special It is extremely difficult to assemble, as it requires the use of a special electrode assembly jig.
The drawback is that it is not suitable for mass production.

An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, and by adopting a main lens with a novel electrode configuration, it is possible to obtain high resolution and good convergence characteristics over the entire area of a phosphor screen. Another object of the present invention is to provide an electron gun for a color picture tube whose electrodes can be easily assembled.

[Means to solve the problem]

The above purpose is to provide a cathode that emits three electron beams arranged in one direction (horizontal scanning direction or less, referred to as the horizontal direction), a control electrode, In an electron gun in which an accelerating electrode and a focusing electrode anode are arranged in this order, the focusing electrode is composed of a first focusing electrode and a second focusing electrode, and the first focusing electrode is provided with a vertically elongated or three-dimensional electrode according to the number of electron beams. a circular electron beam passing hole, and a plurality of parallel plate electrodes (vertical plates) planted in the direction of the second focusing electrode so as to sandwich the electron beam passing hole from the electron beam arrangement direction, and , an electrode with a vertical plate on the outside of the side electron beam passage hole set higher than the vertical plate on the side of the center electron beam passage hole, and a second focusing electrode with a horizontally long electrode or three circular electrodes according to the number of electron beams. A pair or three pairs of parallel plate electrodes (horizontal plates) are installed in the direction of the first focusing electrode so as to sandwich the electron beam passing hole from a direction perpendicular to the electron beam arrangement direction (vertical direction). This is achieved by

[Effect]

Parallel plate electrodes sandwiching the electron beam passage hole of the first focusing electrode (
A quadrupole lens electric field is formed by the parallel plate electrodes (horizontal plates) sandwiching the electron beam passage hole of the second focusing electrode.

In addition, by making the height of the vertical plate provided on the first focusing electrode higher on the outside of both side electron beam passage holes than on the inside, side electron beams can be formed between the outer vertical plate and the inner vertical plate. A gradient electric field is formed to correct the convergence shift.

At this time, the distance of the side electron beam passage hole from the electron gun axis is the same for the control electrode, acceleration electrode, first focusing electrode, and second collector electrode, and the anode is from the electron gun axis of the side electron beam passage hole. The off-axis distance of the electrode is set larger than that of the preceding electrode to achieve convergence of the side electron beams.

From the above two points, it is possible to make the off-axis distance of the side electron beam passing hole of each electrode the same, and it is possible to easily assemble an in-line type electron gun without axis deviation.
An electron gun for a color picture tube that exhibits high resolution characteristics and good convergence characteristics over the entire area of the phosphor screen surface can be obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of an embodiment of an electron gun for a color picture tube according to the present invention, in which (a) is a cross-sectional view showing the structure of the electron gun, and (b) is a cross-sectional view showing the structure of the electron gun. K1. K
2. In: l hot cathode (hereinafter simply referred to as cathode), 1
0 is a control electrode, 20 is an acceleration electrode, 30 is a first focusing electrode,
40 is a second focusing electrode, 50 is an anode (final acceleration electrode), 1
1', 12, 13. 31a, 32a, 33a, 31b,
32b, 33b, 4.1a, 42a, 43a, 41b,
42b, 43b, 51, 52.53 are electron beam passing holes, C is the electron gun axis, CB is the center electron beam, SBI
, SB2 are side electron beams.

In the same figure, cathodes arranged horizontally in a straight line,
, to 2. Kff, the control electrode 10, the accelerating electrode 20, the first focusing electrode 30, the second focusing electrode 40, and the anode 50 which is the final accelerating electrode constitute an in-line color picture tube electron gun.

The first focusing electrode 30 has three circular electron beam passing holes 31. ．． 32,. 33. 4, which is planted perpendicularly in the direction of the second focusing electrode 40, with the electron beam passing hole horizontally sandwiched from the end face facing the second focusing electrode 40 and forming the electron beam passing hole.
parallel flat plates 34, . It has a first flat plate electrode (vertical plate) consisting of 35.36.37. The height of this parallel plate is as follows, assuming that the height of the outer parallel plate 34.37 is hl and the height of the inner parallel plate 35.36 is h2.
hl > h2.

Further, the second focusing electrode 40 has three circular electron beam passing holes 41a, 42a and 43a on the end face of the first focusing electrode 30.
and a second flat plate electrode (horizontal plate) consisting of a pair of parallel flat plates 44 and 45 horizontally planted in the direction of the first focusing electrode 30 with this electron beam passing hole in the vertical direction. There is. These pairs of horizontal plates may be provided separately (ie, three pairs) for each electron beam.

Then, the parallel −゛1′− constituting the second flat plate electrode is
The tips 4.4.3.45a of the plates 44, 4.5 extend in the direction of the first focusing electrode 30, and are vertically vertical with respect to the parallel flat plates 34, 35, 36.37 of the first focusing electrode 30. It is set to be sandwiched at a certain interval from the beginning. Also,
A parallel plate 44 constituting a flat plate electrode of the second focusing electrode 40.
．． 45 tip 44245a and the flat plate electrode 34.35° 36.37 tip 34a, 35a of the first focusing electrode 30,
A constant interval may be set between 36a and 37a.

The end face on the anode 50 side has three circular electron beam passage holes 41b, 4.2b, and 43b.

Three circular electron beam passing holes 51, 5253 are provided on the end face of the second focusing electrode 40 of the anode 50, and the site electron beam 1ffll passing holes 51, . 5
The off-axis distance S2 from the electron gun axis C (aligned with the axis of the center electron beam CB) of No. 3 is 1. 2. 3. With respect to the off-axis distance S of the site electron beam passage hole of the control electrode 10, acceleration electrode 20, first focusing electrode 30, and second focusing electrode 40, there is a relationship of S2>St,
A main lens is formed between the second focusing electrode 40 and the anode 50 to focus the site electron beams SB+, SB2 onto the phosphor screen surface.

Note that the control electrode 10 and the acceleration electrode 20 each have 3
circular electron beam passing holes 11, 1213, 21, 22
．． 23, and three circular electron beam passing holes 31b, 32b,
33b is formed.

The applied voltage applied to each electrode during operation is 50~
170■, OV for control electrode, 400-800 for acceleration electrode
v is the voltage of the first focusing electrode (V[) from 5 to 8 kV,
The anode voltage (Eb) is 25 kV, and a dynamic voltage (DVf) that changes in synchronization with the vertical and horizontal deflection of the electron beam is applied to the second focusing electrode. This dynamic voltage (DVf) is given a potential of 5 to 8 kV, which is equivalent to the potential Vf of the first focusing electrode when the amount of electron beam deflection is 0, and gradually increases as the amount of electron beam deflection increases. When the amount is maximum, the potential becomes 0.4 to I, k, V higher than the first focusing electrode voltage Vf.

When the amount of deflection of the electron beam is 0, as described above, the first focusing electrode 30. Since there is no potential difference between the second focusing electrode 40 and the parallel flat plates (first flat plate electrodes: vertical plates) 34, 35, 37 inside the first focusing electrode and the parallel plates attached to the second focusing electrode 40, Flat plate (second flat plate electrode: horizontal plate) 4
4.45 has no effect on the electron beam, and the electron beam is focused with optimum focus at the center of the phosphor screen surface by the main lens between the second collecting east electrode 40 and the anode 50.

As the amount of deflection of the electron beam increases, the potential of the second focusing electrode 40 becomes higher than the potential of the first focusing electrode 30.
Parallel flat plates (vertical plates) 34, 35, 3 inside the focusing electrode 30
6.37 and a parallel plate (horizontal + Fi, > 4.4., 45) taken up by the second focusing electrode 40.
As the polar lens electric field is formed, the potential difference between the second focusing electrode 40 and the anode 50 decreases, and the focusing effect of the main lens becomes weaker.

The effect of the quadrupole lens electric field is similar to that described in the prior art section.

FIG. 2 is an explanatory diagram of the convergence system of the electron gun according to the present invention shown in FIG.

Fa', Fb are the forces given to the electron beam by the electric field,
The same parts as in FIG. 1 are given the same reference numerals, and (a) shows the deflection at the center of the phosphor screen surface, and (b) shows the deflection at the corner of the phosphor screen surface.

In the same figure (a), at the center of the phosphor screen surface, the potential Vf of the first focusing electrode 30 is different from the potential D of the second focusing electrode 40.
Since it is the same as Vf (Vf=DVf<<<Eb), the distance S2 from the electron gun axis of the site electron beam passage hole 51 at the anode 50 when the deflection amount of the electron beam I is O is the second focusing electrode 40. The side electron beam passage hole 4.1b is larger than the distance S from the electron gun axis of the side electron beam passage hole 4.1b, and the side electron beam passage hole is eccentric to the outside.
13 is a side electron beam passing hole 51.53 (
53 (not shown), the center electron beam CB is bent by the force of Fa toward the center electron beam CB side, and the center electron beam CB passes on the phosphor screen surface. converge with.

In addition, in FIG. 3B, as the amount of deflection of the electron beam increases, the potential DVf of the second electrode 40 changes to the first focusing electrode 3.
0 potential V[If it becomes higher than (Vf<DVf<<Eb)
, the potential difference between the second focusing electrode 40 and the anode 50 decreases, and the site electron beam passage hole 5 of the anode 50], 53(
53 is not shown) is weaker than Fa in FIG. 3(a) above.
Fa>l? a'), as the center electron beam is bent in the direction of CB by the force of Fa', the electron beam 1ζ is
The SBI no longer converges with the center electron beam CB at the phosphor screen surface. At this time,
From the tips 34 a 37 a (37 a not shown) of the outer vertical plates 34 37 (37 not shown) of the first focusing electrode 30 to the tips 35 a , 36 of the inner vertical plates 35 , 36
A gradient electric field directed inward toward the second focusing electrode 40 as shown in the figure is formed.

This inclined electric field gives a focusing effect to the electron beam and acts to bend the side electron beam S B + toward the center electron beam CB by the force of Fb.

the tip 34a of the vertical plate 34.37 of the first focusing electrode 30;
By changing the distance from 37a to the tips 35a and 36a of the vertical plates 35 and 36, the magnitude of the above-mentioned gradient electric field can be controlled from 1 to 1, and the change in the potential DVf of the second focusing electrode 40 , a side electron beam S B + passes through the side electron beam passing hole 5153 (53 is not shown) of the anode electrode 50.
Force Fa' in the direction of the center electron beam CB given to
The force Fb generated by the vertical plates 34.37 and 35.36 produces an effect similar to that of the force Fa in FIG. 3(a), and the side electron beam SB is It also converges with the center electron beam CB at the corners of the screen surface.

In this way, according to the above-mentioned embodiment, the electron beam 1 allows the center electron beam and the side electron beam to be spread over the entire surface of the phosphor screen while keeping the spot diameter small and almost perfectly circular, that is, without reducing the resolution. Beam convergence can be achieved.

Furthermore, as described above, the present invention is not limited to an electron gun having a single stage of focusing electrodes, but can also be applied to an electron gun having multiple stages of focusing electrodes.

Although the above embodiment describes an in-line three-electron beam type electron gun having three cathodes, the present invention is not limited to this, and may include an electron gun having a single cathode common to three electron beams, It goes without saying that the present invention can also be applied to various electron guns having multiple electron beams other than the three-dimensional electron beam.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible not only to obtain an electron gun for a color picture tube that has high resolution characteristics and good convergence characteristics over the entire area of the phosphor screen surface, but also to It is also possible to arrange the site electron beam passage holes between the electrodes on the same axis,
Since accurate axis alignment is easy, it is possible to provide an electron gun for color picture tubes with excellent functionality that greatly contributes to manufacturing yield and quality improvement through simplified assembly.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of an electron gun for a color picture tube according to the present invention, FIG. 2 is an explanatory diagram of the convergence system of the electron gun according to the present invention shown in FIG. 1, and FIG. 3 is a quadrupole lens magnetic field. FIG. 4 is an explanatory diagram of the relationship between the horizontal deflection magnetic field of the binction magnetic field distribution and the electron beam, and FIG. 5 is an explanatory diagram of the shape distortion of the beam spot.
FIG. 6 is an explanatory diagram of an electron gun of a conventional picture tube device, and FIG. 7 is a simple explanatory diagram of the lens action by the quadrupole electric field in FIG. 6. 10...control electrode, 20...acceleration electrode, 30...
...first focusing electrode, 34. 35. 36°37...
...First flat plate electrode (vertical plate), 40...Second focusing electrode, 44. ．． 45...Second flat plate electrode (horizontal plate)
, 50... Anode. Ku 3 or 1 ku ba) ↓Eyes

Claims (1)

[Claims] 1. A cathode for emitting three electron beams arranged in one direction, and facing this cathode, at least a control electrode, an accelerating electrode, a focusing electrode, and an anode. In the electron gun for a color picture tube, the focusing electrode has a beam passing hole through which three electron beams emitted from the cathode pass, and the first focusing electrode is arranged on the accelerating electrode side. It consists of an electrode and a second focusing electrode disposed on the anode side, and the first focusing electrode directs each of the electron beams passing through an electron beam passage hole formed on an end face opposite to the second focusing electrode in the electron beam array direction. comprising a plurality of parallel flat plates arranged in the direction of the second focusing electrode and sandwiched therebetween, the flat plates constituting the parallel plates disposed outside the side electron beam passage hole of the electron beam have heights in the tube axis direction as described above. The height is set higher than the height in the tube axis direction of the flat plate constituting the parallel flat plate planted across the center beam passage hole for the electron beam, and the second focusing electrode is formed on the end face opposite to the first focusing electrode. a first parallel plate and a tube axis, which are erected in the direction of the first focusing electrode and in the direction of the first focusing electrode, sandwiching the electron beam passing through the electron beam passage hole in a direction perpendicular to the arrangement direction of the electron beam; A second flat plate electrode consisting of a pair of parallel flat plates extended so as to face each other at a certain distance in the direction is provided, and the second focusing electrode is provided with a voltage that changes to a value higher than the focus voltage as the deflection angle of the electron beam increases. An electron gun for a color picture tube, characterized in that it is configured to apply a voltage. 2. A cathode for emitting three electron beams arranged in one direction, and facing this cathode, at least a control electrode, an accelerating electrode, a focusing electrode, and an anode in this order in the tube axis direction. In the electron gun for a color picture tube, the focusing electrode is arranged on the accelerating electrode side having a beam passing hole through which three electron beams emitted from the cathode pass, and the focusing electrode is arranged on the accelerating electrode side.
It consists of a focusing electrode and a second focusing electrode disposed on the anode side, and the first focusing electrode directs each of the electron beams passing through an electron beam passage hole formed on an end surface opposite to the second focusing electrode into the electron beam array. comprising a plurality of parallel flat plates placed in the direction of the second focusing electrode across from the direction, and the height of the flat plate in the tube axis direction of the flat plates constituting the parallel plates arranged outside the side electron beam passing hole of the electron beam is provided. The height is set higher than the height in the tube axis direction of the flat plate constituting the parallel flat plate planted across the center beam passage hole for the electron beam,
The second focusing electrode is planted on the first focusing electrode with the electron beam passing through the electron beam passing hole formed on the end face facing the first focusing electrode sandwiched therebetween in a direction perpendicular to the arrangement direction of the electron beam. The second focusing electrode is provided with a second flat plate electrode formed of a pair of parallel flat plates extended so as to overlap with each other so as to sandwich the first parallel flat plate from the perpendicular direction. An electron gun for a color picture tube, characterized in that it is configured to apply a voltage that changes to a value higher than a focus voltage.