KR20000055244A - electron gun in color cathode-ray tube - Google Patents

Abstract

PURPOSE: An electron gun for a color cathode ray tube is to improve a spot size of an electron beam discharged from an electron gun, thereby increasing a resolution of the color cathode ray tube. CONSTITUTION: An electron gun for a color cathode ray tube comprises a first accelerating/focusing electrode for focusing an electron beam, a second accelerating/focusing electrode for accelerating the electron beam, a first electrostatic field control electrode(15) which is disposed in the first accelerating/focusing electrode and has a plurality of electron beam passing holes(19), and a second electrostatic field control electrode which is disposed in the first accelerating/focusing electrode and has a plurality of electron beam passing holes. The electron beam passing holes of the first electrostatic field control electrode is longitudinally formed in the shape of a circle and a line. A protrusion(101) is formed at an upper and a lower portion of the first and second electrostatic field control electrode.

Description

Electron gun in color cathode-ray tube

The present invention relates to a color cathode ray tube, and more particularly to an electron gun for a color cathode ray tube.

A typical color cathode ray tube generally uses an in-line electron gun, and in the cathode ray tube using the in-line electron gun, three electron beams of red (R), green (G), and blue (B) are horizontally aligned. In order to converge the three electron beams in one place of the fluorescent surface, the deflection yoke of the CRT applies a self-convergence using a non-uniform magnetic field.

As shown in FIG. 1, the color cathode ray tube has a panel 1 mounted on the front surface of the color cathode ray tube, and graphite having electrical conductivity is applied to the inner side of the panel 1 while the inside thereof is coated. The funnel (2) is coupled to maintain the vacuum state, the panel (1) and the funnel (2) is formed of a glass (glass) material, and the panel (1) and the funnel (2) of the glass material It is called a glass bulb.

The inner surface of the panel 1 is provided with a fluorescent surface 3 coated with phosphors of red (R), green (G) and blue (B), and is incident on the fluorescent surface 3 behind the fluorescent surface 3. A shadow mask 4 having a color discriminating function of an electron beam to be provided is provided.

The funnel 2 is formed with a tubular neck portion 5 which is retracted to the rear of the funnel 2, and an electron gun 6 for emitting an electron beam is mounted inside the neck portion 5. A deflection yoke 7 is provided on the outer side of the funnel 2 to deflect the electron beam in a horizontal or vertical direction.

The electron gun 6 is composed of a triode and a main lens portion, as shown in FIG.

In the triode, a plurality of cathodes 8 each having a heater built therein and directly emitting hot electrons are arranged inline, and a control electrode for controlling the electron beam emitted from each cathode 8 in front of each cathode 8 is formed. A first grid electrode 9 is provided, and an acceleration electrode (second grid electrode) 10 for accelerating the electron beam sent in a controlled state is provided in front of the control electrode 9.

The main lens unit is provided with a plurality of main lens (electrostatic lens) forming electrodes for accelerating and focusing the electron beam generated at the triode, and the rear direction of the main lens forming electrode, that is, the tube axis direction (ZZ direction). The shielding electrode 13 which connects and weakens the leakage magnetic field of the deflection yoke 7 is connected.

The main lens forming electrode is provided so as to face the first acceleration / focusing electrode (focus electrode) 11 for accelerating and focusing the electron beam and the first acceleration / focusing electrode 11, and the second acceleration for finally accelerating the electron beam. And a focusing electrode (anode electrode) 12.

The control electrode 9 and the acceleration electrode 10 are formed in the shape of a plate, the first acceleration / focusing electrode 11 and the second acceleration / focusing electrode 12 is in the form of a non-cylindrical cylinder (cylinder) It is formed.

As long as the control electrode 9, the acceleration electrode 10, the first and second acceleration / concentration electrodes 11 and 12 and the shielding electrode 13 are arranged in a line in the tube axis direction ZZ, they are rod-shaped electrical insulators. It is fixedly fixed to the pair of bead glass 14.

Openings (a) through which the electron beam passes are formed in the control electrode (9), the accelerating electrode (10), and the first and second acceleration / focusing electrodes (11, 12), respectively. Perforations perpendicular to the advancing direction, that is, perpendicular to the advancing direction of the electron beam, are formed on the same plane, respectively.

In the color cathode ray tube of this structure, the panel 1 in which the fluorescent surface is formed on the inner surface of the cathode ray tube and the funnel 2 coated with graphite having electrical conductivity on the inner side are bonded to each other by fusion glass in a furnace at about 450 ° C.

When an image signal is inputted to the electron gun 6 mounted to emit an electron beam in the tubular neck portion 5 which is retracted to the rear of the funnel 2, each heater installed in each cathode 8 of the electron gun 6 The electron beam is emitted from each cathode 8 by the heat generated by heating and the voltage difference applied to the plurality of electrodes adjacent to each cathode 8.

The electron beam emitted from the cathode 8 is controlled by the voltage applied to each electrode of the electron gun 6, the acceleration electrode 10, the first acceleration / focus electrode (focus electrode) 11 and the first electrode. 2 through each opening through the opening (a) of the acceleration / focusing electrode (anode electrode) 12, controlled, accelerated and focused by the potential difference between the electrodes, and then shadowed in a state deflected by the deflection yoke (7). The image is reproduced by passing through the mask 4 and colliding with the fluorescent surface 3 applied to the inner surface of the panel 1 to emit light.

In this case, the shadow mask 4 has three in-line electron beams corresponding to red (R), green (G), and blue (B) emitted from the electron gun 6 and cross each other around the green in the shadow mask 4. It serves as a color screening function to cause each fluorescent screen 3 of red (R), green (G), and blue (B) of the screen to emit light.

The electron beam focused on the center of the fluorescent surface 3 by the deflection yoke 7 installed outside the funnel 2 and provided with horizontal and vertical deflection coils is deflected in the horizontal or vertical direction of the fluorescent surface 3 while being screened. In the entire region of the impingement hits the fluorescent surface (3).

As described above, the first acceleration / focusing electrode 11 of the non-circular cylinder installed in the electron gun 6 emitting the electron beam to accelerate and focus the electron beam and the second acceleration of the non-circular cylinder to finally accelerate the electron beam. As shown in FIGS. 3 and 4, the structure of the / condenser electrode 12 includes a first electrostatic field control electrode 15 which controls the electrostatic field to eliminate astigmatism. The second electrostatic field control electrode 16 is provided to be orthogonal to the traveling direction of the electron beam, and the second electrostatic field / control electrode 12 controls the electrostatic field to remove astigmatism. It is provided orthogonal to the advancing direction of an electron beam in the state opposed to (15).

The first and second acceleration / focus electrodes 11 and 12 each have a rim portion 17 formed of a semicircle and a straight line along an outer circumference at each one end thereof, and each rim portion 17 is formed. The inner wall 18 of predetermined length extending in the inside of the electrode is formed, respectively.

The rims 17 of the first and second acceleration / concentration electrodes 11 and 12 are opposed to each other with a predetermined distance therebetween, and the first and second electrostatic field control electrodes 15 and 16 are rims. At 17, the first and second electrostatic field control electrodes 15 and 16 are provided at a predetermined depth point.

The first and second electrostatic field control electrodes 15 and 16 are formed with first and second electron beam passing holes 19 and 20 through which electron beams pass, respectively, and the first and second electrostatic field control electrodes 15 are formed. Blade portions 21 are formed at both sides of the 16, respectively, and the first and second electron beam passing holes 19 and 20 are formed in a quadrangular shape.

Another embodiment of the first and second electrostatic field control electrodes 15 and 16 of the first and second acceleration / concentration electrodes 11 and 12 is shown in FIGS. 6A and 6B. A plurality of first electron beam through holes 19 through which electron beams pass are formed in the first electrostatic field control electrode 15 provided in the first acceleration / focus electrode 11, and each of the first electron beam through holes 19 It is formed in the shape of an ellipse.

The first electron beam through hole 19 is composed of a central beam through hole 19a formed at the center and side beam through holes 19b formed at both sides thereof.

The second electrostatic field control electrode 16 provided in the second acceleration / focus electrode 12 has a second electron beam through hole 20 through which an electron beam passes, and the second electron beam through hole 20 is an ellipse. It is formed into an elongate shape.

It is emitted from each cathode 8 of the electron gun configured as described above and passes through the control electrode 9, the acceleration electrode 10, and the first and second acceleration / concentration electrodes 11 and 12, respectively. It accelerates and proceeds to the screen side.

The first electrostatic field control electrode 15 is provided in the first acceleration / focusing electrode 11, and the second electrostatic field control electrode 16 is installed in the second acceleration / focusing electrode 11. In addition, since the rim portion 17 formed of a semicircle and a straight line is formed at one end of each of the first and second acceleration / focusing electrodes 11 and 12 along the outer periphery, the first and second electrostatic field control electrodes ( 15 and 16 are installed in each rim 17 so as to enter more than a predetermined depth into the first and second acceleration / concentration electrodes 11 and 12, and thus the first and second acceleration / concentration electrodes 11 and 12. As the potential of the electrode penetrates deeply into the respective electrodes, the size of each opening a formed in the first and second acceleration / focusing electrodes 11 and 12 is enlarged, and the first and second electrostatic field control electrodes are enlarged. By adjusting the dimensions of (15) and (16), positive convergence adjustment (OCV) of the cathode ray tube is made possible.

As described above, when the size of each opening (a) of the first, second acceleration / focusing electrodes (11) 12 is enlarged, it is sent from the acceleration electrode (10) to the first acceleration / focusing electrode (11) When the electron beam passes through the first acceleration / focusing electrode 11 through the opening a of the first acceleration / focusing electrode 11, and at the first acceleration / focusing electrode 11, the second acceleration / focusing electrode 11. When the electron beam sent to (12) passes through the second acceleration / focusing electrode 12 through the opening a of the second acceleration / focusing electrode 12, the electron beam becomes the first, second acceleration / focusing electrode ( 11) The main lens unit (main focus electrostatic force) is much stronger in the opening (a) formed by each of the rims 17 of the 12 (12) in the horizontal direction (XX direction) than in the vertical direction (YY direction) The effective lens diameter of the lens) becomes much larger in the horizontal direction than in the vertical direction.

Thus, as the electron beam focusing force of the main focusing electrostatic lens becomes weaker in the horizontal direction than in the vertical direction, the focusing force of the entire electron beam is significantly weaker in the horizontal and vertical directions, and thus the focal length is changed by the difference of the electron beam focusing force. As a result, astigmatism occurs.

As described above, the astigmatism generated in the main focusing electrostatic lens is controlled by the first and second electrostatic field control electrodes 15 and 16 installed in the first and second acceleration / focusing electrodes 11 and 12, respectively. As the focusing force of the electron beam passing through the first and second acceleration / focusing electrodes 11 and 12 is made the same in the vertical direction and the horizontal direction, it is removed.

That is, the electron beam sent to the first acceleration / focusing electrode 11 passes through the first electron beam passing hole 19 formed in the first electrostatic field control electrode 15, and the second acceleration / focusing electrode 12. The electron beam sent to the second electron beam passes through the hole 20 formed in the second electrostatic field control electrode 16.

At this time, the electrostatic field penetrating into the opening (a) when the electron beam passes through the opening (a) of the first acceleration / focusing electrode 11 is controlled by the first electrostatic field control electrode 15, the second When the electron beam passes through the opening a of the acceleration / focusing electrode 12, the electrostatic field penetrating into each opening a is controlled by the second electrostatic field control electrode 16.

Therefore, the astigmatism generated in the first and second acceleration / focus electrodes 11 and 12 is removed by the first and second electrostatic field control electrodes 15 and 16.

However, since the electron gun for the conventional color cathode ray tube is small in the main lens aperture, that is, the size of the opening (a) of the first and second acceleration / focusing electrodes 11 and 12 of the electron gun 6, the spherical aberration increases. The size becomes large, which causes the resolution of the color cathode ray tube to deteriorate, and as the diameter of the main lens becomes smaller, the spot size in the horizontal direction on the screen becomes larger and the manufacturability is poor.

Here, the lens size in the horizontal and vertical directions of the main lens is almost determined by the structure of the first and second electrostatic field control electrodes 15 and 16 of the first and second acceleration / focus electrodes 11 and 12. .

That is, it is difficult to manufacture the blade portion 21 because the thickness of the main lens can be increased when the thickness of the blade portion 21 of the first and second electrostatic field control electrodes 15 and 16 is formed to be large. .

In addition, as shown in FIG. 5, the equipotential of the electron beam has a steep curve in the horizontal direction (XX direction) by blade portions 21 formed on both sides of the first and second electrostatic field control electrodes 15 and 16, respectively. Therefore, there is an adverse effect of reducing the diameter of the entire main lens in the horizontal direction.

When the heights of the blade portions 21 of the first and second electrostatic field control electrodes 15 and 16 are not the same, the astigmatism and the positive convergence characteristics are red (R), green (G), and blue (B). As the electron gun changes, the correction electrode for correcting the above characteristics is provided at the bottom of the shielding electrode 13 so that the above characteristics can be corrected. The resolution of the becomes lower.

6A and 6B, the blade portion 21 is not formed in the electron beam passing holes 19 and 20 formed in the first and second electrostatic field control electrodes 15 and 16, and the first portion is formed. By forming the shape of the two electron beam through holes 19 and 20 in the shape of an ellipse, the first and second electrostatic field control electrodes 15 and 16 are plate-shaped (thickness). Is about 0.6 mm), so that the first and second electrostatic field control electrodes 15 and 16 are welded to the first and second acceleration / concentration electrodes 11 and 12, and In addition to a large change in characteristics, another correction electrode is required to simultaneously satisfy the astigmatism and the positive convergence characteristics of the electron beam through holes 19 and 20 of the first and second electrostatic field control electrodes 15 and 16. do.

The present invention has been made to solve the above-mentioned problems, and the electron beam passing holes of the first and second electrostatic field control electrodes installed in the first and second acceleration / concentration electrodes of the cathode ray tube electron gun are formed in different shapes, respectively. At the same time, protrusions are provided on the upper and lower portions of the first and second electrostatic field control electrodes, respectively, to enlarge the main lens aperture of the electron gun in the horizontal direction and to correct astigmatism of the cathode ray tube. The purpose is to improve the resolution of the color cathode ray tube by improving the spot size.

In order to achieve the above object, the present invention provides a first acceleration / focusing electrode for focusing an electron beam, a second acceleration / focusing electrode for accelerating the electron beam, and installed in the first acceleration / focusing electrode to pass through a plurality of electron beams A color cathode ray tube equipped with a first electrostatic field control electrode having a ball and a second electrostatic field control electrode provided in the second acceleration / concentration electrode and having an electron beam passing hole formed therein, wherein the first electrostatic field control electrode includes: Each electron beam passing hole is formed in an elongated shape consisting of a circle and a straight line, and an electron gun for a color cathode ray tube is provided by forming protrusions on the upper and lower portions of the first and second electrostatic field control electrodes, respectively.

1 is a cross-sectional view showing the structure of a general color cathode ray tube.

Figure 2 is a cross-sectional view showing the structure of a conventional electron gun for color cathode ray tube.

Figure 3 is a perspective view showing a state in which the first, second acceleration / focusing electrode structure of the conventional electron gun partially cut.

Figure 4 is a perspective view showing the structure of the first, second electrostatic field control electrode of the conventional first, second acceleration / focusing electrode.

5 is a graph illustrating an equipotential state of an electron beam generated by first and second electrostatic field control electrodes in a conventional first and second acceleration / focus electrodes.

6A and 6B illustrate another embodiment of the first electrostatic field control electrodes installed on the first and second acceleration / focus electrodes of the conventional electron gun, respectively.

7A and 7B are a perspective view and a front view showing a first electrostatic field control electrode installed on the first acceleration / focus electrode of the electron gun for the color cathode ray tube of the present invention;

8A and 8B are a perspective view and a front view showing a second electrostatic field control electrode installed on the second acceleration / focusing electrode of the electron gun of the present invention.

9A to 9C illustrate another embodiment of the electron beam through hole formed in the second electrostatic field control electrode of the second acceleration / focusing electrode of the present invention.

10A and 10B illustrate another embodiment of the second electrostatic field control electrode of the second acceleration / focusing electrode of the present invention in a perspective view.

11 is a graph showing an electron beam equipotential curve in a state in which the main lens diameter is enlarged by the first and second electrostatic field control electrodes of the electron gun of the present invention.

12 is a graph showing an equipotential curve of an electron beam formed by each protrusion of the first and second electrostatic field control electrodes of the present invention.

* Description of the symbols for the main parts of the drawings *

101, 101a: projection 102: weld

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 7A to 8B.

Since the structure of the electron gun for color cathode ray tubes is mentioned in the conventional structure, the overlapping part is abbreviate | omitted and the same code | symbol is attached | subjected to the conventional structure only.

7A and 7B are a perspective view and a front view showing a first electrostatic field control electrode installed on the first acceleration / focus electrode of the electron gun for a color cathode ray tube of the present invention, and FIGS. 8A and 8B are second acceleration / focus electrodes of the electron gun of the present invention. A perspective view and a front view of a second electrostatic field control electrode provided in the above.

The present invention is equipped with an electron gun (6) for emitting an electron beam, the electron gun (6) is provided with a first acceleration / focusing electrode (11) for focusing the electron beam, the electron gun (6) for accelerating the electron beam The second acceleration / focus electrode 12 is provided.

In the first acceleration / focusing electrode 11, a first electrostatic field control electrode 15 for controlling the electrostatic field penetrating into the opening a formed in the first acceleration / focusing electrode 11 is provided. In the second acceleration / focusing electrode 12, a second electrostatic field control electrode 16 for controlling the electrostatic field penetrating into the opening a formed in the second acceleration / focusing electrode 12 is provided.

7A and 7B illustrate a perspective view and a front view of the first electrostatic field control electrode 15 of the present invention, wherein the first electrostatic field control electrode 15 includes a plurality of first electron beam through holes 19 through which an electron beam passes. ) Is formed in an elongated shape consisting of circles and straight lines, and protrusions 101 protruding by a predetermined length are formed on upper and lower portions of the first electrostatic field control electrode 15, respectively.

A plurality of welds 102 are formed on upper and lower ends of the first electrostatic field control electrode 15 so as to be fusion-bonded with an inner surface of the first acceleration / focus electrode 11. 1 may be integrally formed with the electrostatic field control electrode 15, or may be manufactured by a plurality of members and coupled to the first electrostatic field control electrode 15.

The first electron beam through hole 19 of the first electrostatic field control electrode 15 has a longitudinal center beam through hole 19a having a cylindrical track shape in which the vertical direction consisting of circles and straight lines is larger than the horizontal direction, and the circle and straight lines. The vertical direction is made of a longitudinal side beam through-hole (19b) of the dock type (only) larger than the horizontal direction.

The vertical diameter of the center beam through hole 19a is smaller than the vertical diameter of the side beam through hole 19b.

8A and 8B illustrate a perspective view and a front view of the second electrostatic field control electrode 16 of the present invention, wherein a second electron beam through hole through which an electron beam passes through a central portion of the second electrostatic field control electrode 16 is formed. 20 is formed in a circular shape, and protrusions 101a having a predetermined height are formed on the upper and lower portions of the second electrostatic field control electrode 16, respectively.

Each of the protrusions 101a may be integrally formed with the second electrostatic field control electrode 16 or may be separately manufactured and coupled to the second electrostatic field control electrode 16.

The length l between the outer surface of the second electrostatic field control electrode 16 and the outer periphery of the second electron beam through hole 20 is formed by a predetermined length (about 0.5 to 0.7 mm).

Another embodiment of the shape of the second electron beam through hole 20 of the second electrostatic field control electrode 16 is formed in a square (square, rectangular, etc.) or circumferential track shape as shown in Figs. 9A to 9C.

Meanwhile, as another embodiment of the second electrostatic field control electrode 16, as shown in FIGS. 12A and 12B, the protrusion 101a may be formed only at one of the upper and lower portions of the second electrostatic field control electrode 16. Alternatively, the protrusion 101a is not formed on the second electrostatic field control electrode 16.

The operation of the present invention configured as described above is as follows.

First, the electron beam emitted from each cathode 8 of the electron gun and passing through the control electrode 9 and the acceleration electrode 10 is controlled and accelerated, and the electron beam accelerated by the acceleration electrode 10 is the first lens part. , Through the openings (a) of the two acceleration / focusing electrodes (11) and (12) through the first and second acceleration / focusing electrodes (11) (12), focusing and finally accelerating to proceed to the screen side.

At this time, when the electron beam passes through the opening a formed by the rim 17 of the first and second acceleration / focusing electrodes 11 and 12, the electron beam in the respective openings a is in the vertical direction (YY direction). Since the field penetration in the horizontal direction (XX direction) is much stronger than that of the effective lens diameter of the main lens portion (main focusing electrostatic lens), the horizontal direction becomes much larger than the vertical direction, and therefore the electron beam focusing force of the main lens portion is vertical. As the focus of the electron beam becomes weaker in the horizontal direction than in the direction, and the focus of the overall electron beam becomes significantly weaker in the vertical and horizontal directions, the focal length due to the difference in the focusing force of the electron beam is changed, thereby causing astigmatism.

Therefore, the electron beam passes through the first acceleration / focusing electrode 11 between the traveling axes of the electron beam to remove the astigmatism generated by the main lens unit (main focusing electrostatic lens) as shown in FIGS. 7A and 7B. The first electrostatic field control electrode 15 having a plurality of first electron beam through holes 19 having different shapes is provided, and the second acceleration / focus electrode 12 is shown in FIGS. 8A and 8B. By providing the second electrostatic field control electrode 16 having the second electron beam through hole 20 through which the electron beam passes, the first and second electrostatic field control electrodes 15 and 16 are provided with the first and second electrostatic field control electrodes 16 and 16. 2 Focusing force of the electron beam passing through the acceleration / focusing electrodes 11 and 12 is the same in the vertical direction and the horizontal direction, and each opening of the first and second acceleration / focusing electrodes 11 and 12 is performed (a). As the electron beam passes through, it penetrates into the first and second acceleration / focus electrodes 11 and 12 through the respective openings a). As the electrostatic sheets control the removal of the astigmatism of the main lens portion.

That is, the plurality of first electron beam through holes 19 formed in the first electrostatic field control electrode 15 are formed in a circle and a straight line, and have a longitudinal track type in which the vertical direction (YY direction) is larger than the horizontal direction (XX direction). Since the central beam through hole 19a and the vertical side are formed as a longitudinal side beam through hole 19b having a larger shape than the horizontal direction, the electron beam sent to the first acceleration / focusing electrode 11 receives the first acceleration / The electrostatic field penetrating into the aperture a when passing through the aperture a of the focusing electrode 11 is controlled by the first electrostatic field control electrode 15 so that the first acceleration / focus electrode 11 The generated astigmatism, that is, the astigmatism of the medium and side beam electrostatic lenses is eliminated, and the characteristics of the positive convergence (OCV) are improved.

In addition, since the second electron beam passing hole 20 of the second electrostatic field control electrode 16 is formed in a circular shape, the electron beam sent to the second acceleration / focusing electrode 12 receives the second acceleration / focusing electrode 12. As the electrostatic field penetrating into the opening (a) is controlled by the second electrostatic field control electrode 16, the astigmatism generated in the second acceleration / focusing electrode 12 is Removed.

Here, protrusions 101 are formed on the upper and lower portions of the first electrostatic field control electrode 15, and protruded by a predetermined length on the upper and lower portions of the second electrostatic field control electrode 16. By forming the protrusions 101a respectively, the lens aperture is enlarged in the horizontal direction (XX direction) of the main lens portion, so that the spot size in the horizontal direction of the screen becomes smaller and the equipotential curve of the electron beam becomes smooth as shown in FIG. The equipotential distribution formed by the protrusions 101 and 101a may be adjusted by adjusting the electron beam equipotential in the vertical direction (YY direction) of the electrostatic field control electrodes 15 and 16 as shown in FIG. Astigmatism of the main lens is corrected.

In addition, the equipotential curve varies according to the shape and size of each first electron beam through hole 19 of the first electrostatic field control electrode 15, that is, the center beam through hole 19a of the first electron beam through hole 19. ) And the vertical diameter of the side beam through-hole 19b is smaller than the horizontal diameter, thereby eliminating astigmatism between the central beam and the side beam electrostatic lenses, and improving the positive convergence characteristics.

In addition, the spot shape varies with the shape of the second electron beam through hole 20 formed in the second electrostatic field control electrode 16 of the second acceleration / focus electrode 12, and the second electron beam through hole 20 is formed. Since the amount of astigmatism also varies depending on the size of the astigmatism, the astigmatism can be removed by adjusting the size and shape of the second electron beam through hole 20 of the second electrostatic field control electrode 16.

On the other hand, if the protrusion 101a of the second electrostatic field control electrode 16 is formed only at one of the upper and lower portions, the same effect as described above can be obtained, and the first and second electrostatic field control electrodes 15 and 16 are provided. ) Is installed so as to enter a predetermined depth in the rim portion 17 of the first and second acceleration / focusing electrodes 11 and 12 so that the positive convergence (OCV) and astigmatism of the cathode ray tube can be adjusted.

Since a plurality of welding parts 102 are formed on upper and lower ends of the first electrostatic field control electrode 15, the first electrostatic field control electrode 15 is positioned in the first acceleration / focus electrode 11, respectively. Then, each welding portion 102 of the first electrostatic field control electrode 15 is fusion-bonded to the inner surface of the first acceleration / focusing electrode 11, so that the first electrostatic field control electrode 15 is the first acceleration / focusing electrode. It is fixed in (11).

As described above, the present invention provides a first electrostatic field control electrode in which a plurality of first electron beam passing holes having different shapes are formed in the first acceleration / focusing electrode, which is the main lens of the electron gun, and is circular in the second acceleration / focusing electrode. By providing a second electrostatic field control electrode having a second electron beam through hole of the first and second electrostatic field control electrodes, the diameter of the main lens portion is enlarged by each electron beam through hole of the first and second electrostatic field control electrodes. The astigmatism is removed and the positive convergence (OCV) characteristic is improved.

In addition, by forming protrusions on the upper and lower portions of the first and second electrostatic field control electrodes, respectively, the astigmatism is increased in the first and second acceleration / focus electrodes by improving the spot size of the electron beam emitted from the electron gun by the respective protrusions. The correction also increases the resolution of the color cathode ray tube.

Further, not only the fabrication of the first and second electrostatic field control electrodes is easy, but also the number of the first and second electrostatic field control electrodes can be reduced, thereby reducing the production cost of the color cathode ray tube.

Claims (5)

A first electrostatic field control electrode for focusing the electron beam, a second acceleration / focusing electrode for accelerating the electron beam, a first electrostatic field control electrode provided in the first acceleration / focusing electrode, and having a plurality of electron beam passing holes formed therein; In the color cathode ray tube provided with the electron gun provided with the 2nd electrostatic field control electrode provided in the 2nd acceleration / concentration electrode, and the electron beam passage hole formed, Each electron beam passing hole of the first electrostatic field control electrode is formed in a vertical shape consisting of a circle and a straight line, and the projections are formed on the upper and lower portions of the first and second electrostatic field control electrodes, respectively. Tolerance gun. The method of claim 1, An electron gun of a color cathode ray tube, wherein the center beam through hole has a smaller vertical diameter than the side beam through hole. The method of claim 1, Electron beam passing hole shape of the second electrostatic field control electrode is an electron gun of a color cathode ray tube, characterized in that formed in any one of a circular or square and circumferential track type. The method of claim 1, The projection of the second electrostatic field control electrode, the electron gun of the color cathode ray tube, characterized in that formed in any one of the upper, lower. The method of claim 1, The upper and lower portions of the first electrostatic field control electrode, a plurality of welding parts for fusion bonding with the inner surface of the first acceleration / focusing electrode, respectively, characterized in that the electron gun for a color cathode ray tube.