KR100335087B1 - electron gun for a cathode ray tube - Google Patents

Abstract

The present invention is to improve the electrode structure according to the wide angle cathode ray tube, to remove the eccentric distance due to the wide angle in advance and to remove the haze.

To this end, the present invention, the first electrode for controlling the R, G, B beam emitted from the cathode, the second electrode for accelerating the controlled R, G, B beam, and the accelerated R, G, B An electron gun for a color cathode ray tube including a third electrode for focusing a beam and a fourth electrode for accelerating the focused R, G, and B beams, wherein the electron gun is arranged around the R, G, and B beam passing holes of the second electrode. A long depression is formed, the depth of the depression formed on the R, B beam side is formed differently from the depth of the depression formed on the G beam side, R, G, B beam through hole is formed in the fourth electrode, R, B Provided is an electron gun for a color cathode ray tube, wherein the size of the beam through hole is formed to be relatively larger than that of the G beam through hole.

Description

Electron gun for a cathode ray tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube suitable for wide angle angle.

In general, a color cathode ray tube is a panel (1) having R, G and B fluorescent films coated on its inner surface as shown in FIG. 1, and a panel fused to a rear end of the panel to maintain a vacuum inside the CRT. (2), an electron gun 5 enclosed in the neck portion 3 of the panel to emit an electron beam 4, a deflection yoke 6 for deflecting an electron beam emitted from the electron gun, and the deflection yoke It consists of a dichroic electrode 7 having a dichroic function of the deflected electron beam.

As shown in FIG. 2, the electron gun 5 includes a cathode 10 that independently radiates an R beam, a G beam, and a B beam, and three cathodes disposed at a predetermined distance from the cathode. The first electrode 11, which is a common lattice, and the second electrode 12, the third electrode 13, the fourth electrode 14, the fifth electrode 15, and the sixth at a predetermined distance from the first electrode. Electrodes 16 are sequentially arranged, and the sixth electrode includes a shield cup 17 having a BSC (bulb space connector) (not shown) to shield external and magnetic fields.

The image reproduction process of the color cathode ray tube having such a configuration is as follows.

When an image signal is inputted to the electron gun 5 enclosed in the neck portion 3 of the panel 2, the electron beam 4 is emitted from the cathode (not shown) of the electron gun, and the emitted electron beam is each electrode of the electron gun. It is controlled, accelerated and focused by the voltage applied to it, and then passes through the dichroic electrode 7 in the horizontal and vertical direction by the static magnetic field of the deflection yoke 6 to the inner surface of the panel 1. By emitting the coated phosphor 8, an image is reproduced on the screen.

Meanwhile, the deflection yoke 6 attached to the panel 2 acts to deflect the electron beam 4 focused at the center of the screen to the entire screen area.

That is, in the color cathode ray tube using an in-line electron gun, since three electron beams 4 of red, green, and blue are arranged side by side horizontally, in order to converge the 3 electron beams in one place of the screen, they are nonuniform. A self-convergence deflection yoke 6 using a magnetic field is used.

The magnetic field generated in the deflection yoke 6 to which the self-focusing type is applied is distributed as follows.

The horizontal deflection magnetic field is distributed in a pin-cusion type as shown in FIG. 3A, and the vertical deflection magnetic field is distributed in a barrel shape as shown in FIG. 3B.

This prevents mis-convergence of the electron beam on the screen.

However, as illustrated in FIGS. 4A and 4B, the deflection magnetic field may be described by dividing into two-pole and four-pole components, which will be described in detail below.

First, the bipolar component serves to deflect the electron beam in the horizontal (H) and vertical (V) directions, and the quadrupole component focuses the electron beam in the vertical direction and diverges in the horizontal direction.

In other words, the quadrupole component distorts the spot of the electron beam as astigmatism occurs.

Therefore, even if the magnetic field is close to uniform, the electron beam is subjected to significant astigmatism at the periphery of the screen due to the fine pincushion or barrel magnetic component, which distorts the spot of the electron beam.

5A and 5B illustrate the distortion of the electron beam spot in more detail.

5A and 5B, the electron beam spot has the correct shape because no deflection magnetic field is applied at the center of the screen, but at the periphery of the screen, as mentioned above, the beam diverges in the horizontal direction and overconcentrates in the vertical direction, thereby distorting the high density. A horizontal core 20 and a haze 21, which is a phenomenon of low-density spreading up and down, are generated.

In short, it causes resolution deterioration at the periphery of the screen.

The problem is that the larger the cathode ray tube, or the larger the angle of deflection, the greater.

In other words, as the screen becomes larger, the resolution deterioration in the periphery of the screen becomes more and more wider as the angle of widening of the front and rear widths of the CRT decreases.

Therefore, in order to reduce the haze generated in the periphery of the screen as described above, the necessity of adjusting the electron beam by improving the structure of the electrode forming the lens is increasing.

In short, a number of patents have been issued according to the necessity, and only a few of them are listed, Japanese Patent Publication No. 60-34783, Japanese Patent Publication No. 7-29511, Japanese Patent Publication No. 1-194246, and Japanese Patent Publication No. 4- 249837, US patent usp 4,641,058, US patent usp 4,886,998, US patent usp 4,358,703, US patent usp 4,558,253, US patent usp 4,629,933, and the like.

First, in the case of the conventional electron gun as shown in Fig. 6A, before the electron beam is incident on the main lens, the electron beam is lateralized by the depression 12a of the second electrode 12.

As shown in FIG. 6B, when the fourth electrode 14 in which both the peripheral beam passage hole 14a and the central beam passage hole 14b are formed in a circular shape is added, as shown in FIG. 6C, before the main lens is incident. The trend of horizontalizing the electron beam is maintained.

That is, since the second electrode 12 diverges the electron beam horizontally and focuses it vertically, the deflection aberration in the vertical direction is reduced when the electron beam crosses the deflection center before the main lens is incident. As received, the peripheral hase (see 21 in FIG. 5A) is also reduced.

However, as shown in FIG. 6C, the shape of the electron beam is elongated at the center of the screen by the depressions 12a and 12b formed in the second electrode 12, which indicates the depression force of the second electrode. The harder it is, the longer it becomes.

Therefore, the vertical size (V-size) of the pixel is increased in the center of the screen, thereby reducing the resolution of the center of the screen. Accordingly, the design of the recesses 12a and 12b plays an important role in controlling the size of the pixel close to the circular shape.

Secondly, in the case of the conventional electron gun as shown by the dotted line shown in FIG. 6D, the electron gun has an eccentric distance S of a predetermined electron beam passing hole in the electron gun, but the distance is reduced at the center of the screen, thereby forming almost one point.

However, recently developed color cathode ray tubes are attempting to reduce the width of the front and rear of the receiving tube as much as possible.

Therefore, the deflection angle increases as the width of the front and rear decreases. For example, the amount of the deflection angle increases from 110 degrees to 124 degrees in the conventional 90 degrees, in which case, the distance from the main lens M to the screen (hereinafter referred to as "L dimension" Will be reduced).

As shown in the solid line shown in FIG. 6D, when the L dimension is reduced, the OCV (S2 × 2) at the center of the screen is increased, and thus, R, G, and B 3 electron beams cannot be formed at one point. This results in a convergence error.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and the object of the present invention is to improve the electrode structure according to the wide angled cathode ray tube, to remove the eccentricity caused by the wide angle, and to eliminate the haze.

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

2 is a cross-sectional view showing the structure of a general electron gun.

3A is a schematic diagram showing a horizontal deflection magnetic field generated in a general deflection yoke.

Figure 3b is a schematic diagram showing a vertical deflection magnetic field generated in a general deflection yoke.

Figure 4a is a schematic diagram showing a state in which the shape of the electron beam is changed by the horizontal deflection magnetic field generated in a general deflection yoke.

Figure 4b is a schematic diagram showing a state in which the shape of the electron beam is changed by the vertical deflection magnetic field generated in a general deflection yoke.

5A is a front view showing the shape of an electron beam spotted on a screen by a deflection magnetic field generated in a general deflection yoke;

5B is a schematic diagram showing a spot difference between a general screen periphery and a screen center.

Figure 6a is a front view showing the shape of the second electrode according to the prior art.

Figure 6b is a front view showing the shape of the fourth electrode according to the prior art.

6C is a schematic diagram showing a traveling state of an electron beam by a second electrode and a fourth electrode according to the prior art;

6D is a schematic diagram showing the relationship between the core and the OCV of the fourth electrode in the prior art.

7A is a front view showing a first embodiment of a fourth electrode according to the present invention.

FIG. 7B is a sectional view of FIG. 7A; FIG.

Fig. 7C is a schematic diagram showing the traveling state of the electron beam by the fourth electrode of the present invention.

8 is a cross-sectional view showing the shape of the second electrode according to the present invention.

9 is a schematic diagram showing an electron beam traveling state by the second electrode and the fourth electrode of the present invention.

10A is a front view showing a second embodiment of a fourth electrode according to the present invention;

10B is a sectional view of FIG. 10A.

Explanation of symbols for main parts of the drawings

4: R, G, B beam 10: cathode

11: first electrode 13: third electrode

24, 25: electrode body 120: second electrode

121a: R and B beam side depressions 122a: G beam side depressions

140: fourth electrode 141: R, B beam passing hole

142: G beam through hole

In order to achieve the above object, the present invention, the first electrode for controlling the R, G, B beam emitted from the cathode, the second electrode for accelerating the controlled R, G, B beam, and the accelerated R An electron gun for a color cathode ray tube including a third electrode for focusing G, B beams and a fourth electrode for accelerating the focused R, G, B beams, the R, G, B beams passing through the second electrode. A horizontal depression is formed around the ball, and the depth of the depression formed on the R and B beams is different from the depth of the depression formed on the G beam, and the R, G, B beam through holes are formed in the fourth electrode. To provide an electron gun for the color cathode ray tube, the size of the R, B beam through hole is formed relatively larger than the size of the G beam through hole.

Referring to the drawings to describe the above content in more detail as follows.

FIG. 7A is a front view showing a first embodiment of a fourth electrode according to the present invention, and FIG. 7B is a sectional view of FIG. 7A.

As shown in FIGS. 7A and 7B, the present invention provides a distance between a center of the peripheral beam through hole 141 that is the R and B beams formed in the fourth electrode 140 and a center of the central beam through hole 142 that is the G beam. As solved by reducing the eccentric distance (S), in more detail as follows.

The shape of the R, B beam passing hole 141, which is the peripheral beam passing hole of the fourth electrode, is eccentric to the G beam passing hole 142, which is the central beam passing hole, and the semicircle, which is the outermost part of the peripheral beam passing hole, is located at It is set to the same position where the semicircle, the outermost part of the existing peripheral beam passing hole, is located.

The semi-circle is moved from the center of the semi-circle to the predetermined amount of the central beam through hole 142, while removing the predetermined amount W while moving both ends of the semi-circle.

In detail, the distance between the center of the semi-circle located in the outermost part and the center of the center beam through hole 142 is set to S as in the past, and the center of the part removed by moving the predetermined amount (W) and the center beam passes. The distance from the center of the ball is S ', and the distance between the center of the semicircle formed after being moved and the center of the center beam passing hole is S ".

That is, the shape of the peripheral beam through-hole 141, the semi-circles are formed on both sides to have a predetermined size of R1 and R2, the outer convex shape, and R1 and R2 at this time may be the same or not the same.

The distance between the center of R1 and the center of the center beam through-hole 142 is the same as that of S of the other electrode, and when the distance between the center of R2 and the center of the center beam through-hole is S ", (S" The value of + S) / 2 becomes S '.

On the other hand, S 'is made smaller than S, so that the center of the circle drawn by R1 is the same as other electrodes, thereby eliminating the eccentricity caused by haze and wide angle that appear around the screen, as well as the mandrel used in the conventional beading process. Because you can use it, the production cost is reduced.

Further, the center beam through hole of the fourth electrode is circular, and the peripheral beam through hole is horizontally formed, and as shown in FIG. 7B, h2 < h1 is formed.

10A is a front view illustrating a second embodiment of a fourth electrode according to the present invention, and FIG. 10B is a cross-sectional view of FIG. 10A.

As shown in FIGS. 10A and 10B, the fourth electrode may be stacked in two sheets.

That is, one sheet is an electrode body 24 having an electron beam passing hole formed to have S, and the other sheet is an electrode body 25 having an electron beam passing hole formed to have S '.

Meanwhile, as illustrated in FIG. 8, the second electrode 120 has a depth of the recess 122a formed at the side of the central beam through hole 122 as tc and is formed at the side of the peripheral beam through hole 121. When the depth of the recessed part 121a is ts, it is made so that it may become a condition of tc> ts.

The reason for this is to overcome the structural limitations of the fourth electrode 140. As described above, the depth of the recess 121a formed at the peripheral beam passage hole side of the second electrode is formed at the central beam passage hole side. By making it shallower than the depth of 122a, an eccentric distance can be removed beforehand.

Therefore, in order to reduce Outer Convergnce Variance (OCV) (see solid line), which is an eccentric distance according to the wide angle of view shown in FIG. 6D, the fourth electrode (see 14 of FIG. 6B) is illustrated. ) Is reduced to S '.

When the electron beam passing hole is formed as S 'as described above, the electron beam is incident more inwardly than before, thereby reducing the OCV of the electron beam on the screen, thereby satisfying the convergence at the center of the screen.

However, as shown in FIGS. 7A and 7B, since the fourth electrode 140 is horizontally stretched, as shown in FIG. 7C, the diverging action (see arrow and solid line) and the vertical (V) are horizontally H. ), A focusing action (see arrow and solid line) is added to cause the electron beam horizontally enlarged by the second electrode 120 to be further horizontalized.

This phenomenon does not occur in the case of the center beam (G beam). This is because the center beam through hole 142 of the fourth electrode is formed in a circular shape.

Therefore, as the electron beam is lateralized by the peripheral beam through hole 141 of the fourth electrode, unbalance of the electron beam is generated at the center of the screen.

Also, the center beam (G beam) is close to a circle, but this is also a problem because the peripheral beams (R beam, B beam) become longitudinal electron beams.

To solve this problem, as illustrated in FIGS. 8 and 9, the electron beam lengthening may be solved by weakening the action of the second electrode 120.

That is, in the conventional second electrode (see 12 of FIG. 6A), the depth of the recess 121a formed at the peripheral beam passage hole side is formed to be shallower than the depth of the recess 122a formed at the center beam passage hole side. The depth of the depression formed on the peripheral beam through-hole side is 10 to 30% of the depth of the depression formed on the central beam through-hole side.

As such, when the depths of the central beam through hole side depressions 122a and the peripheral beam through hole side depressions 121a formed in the second electrode 120 are not different from each other, the peripheral beam through holes of the fourth electrode 140 ( In the same way as 141, the central beam through hole 142 should be made in the same way.

In this case, since the depths of the recesses 121a and 122a formed in the second electrode 120 are made thin as in the related art, the same depth of the recesses can be maintained as a whole.

As described above, the present invention changes the S value of the fourth electrode in order to prevent the OCV from growing wider, and adjusts the depth of the depression of the second electrode to prevent the growing of the electron beam. It is possible to reduce the OCV of the electron beam corresponding to the wide angle in addition to removing the haze caused by the electron beam lengthening.

Therefore, even if the width of the monitor and various image media in which the cathode ray tube is used can be reduced, accurate convergence and accurate focus can be obtained.

In addition, as the width of the cathode ray tube decreases, the space can be utilized as much and the material cost can be reduced.

And it includes all the effects mentioned in the detailed description of the invention.

Claims (6)

A first electrode for controlling the R, G, and B beams emitted from the cathode, a second electrode for accelerating the controlled R, G, and B beams, and a third electrode to focus the accelerated R, G, and B beams In the electron gun for a color cathode ray tube including a fourth electrode for accelerating the focused R, G, B beams, A horizontal recess is formed around the R, G, and B beam passing holes of the second electrode, and the depth of the depression formed on the R and B beams is different from the depth of the depression formed on the G beam. R, G, B beam through hole is formed in the fourth electrode, the size of the R, B beam through hole, the electron gun for a color cathode ray tube, characterized in that is formed larger than the size of the G beam through hole. The method of claim 1, An electron gun for a color cathode ray tube, characterized in that the depth of the depression formed on the R and B beam passage holes is smaller than the depth of the depression formed on the G beam through holes. The method of claim 2, An electron gun for a color cathode ray tube, characterized in that the depth of the depression formed on the R and B beam passage holes is 10 to 30% of the depth of the depression formed on the G beam passage holes. The method of claim 1, An electron gun for a color cathode ray tube, wherein the R and B beam passing holes of the fourth electrode are eccentric to the G beam passing hole side. The method of claim 4, wherein The electron beam for the cathode ray tube, characterized in that the R, B beam passing holes of the fourth electrode are laterally eccentric to the G beam passing hole side. The method according to claim 1 or 5, The fourth electrode; For a color cathode ray tube, the electrode body having circular R, G, B beam through holes and the electrode body having circular G beam through holes together with the transversely oriented R, B beam through holes are laminated together. Electron gun.