KR20000008878A - Electron gun for colored cathode ray tube - Google Patents

Abstract

The present invention relates to an electron gun that scans an electron beam toward the fluorescent surface applied to the inner surface of a panel in a large TV or high-definition industrial monitor, and improves the resolution at the periphery of the screen by correcting astigmatism according to the deflection force of the electron beam. .

To this end, a three-pole portion comprising an electron radiating means for radiating the electron beam 5, a control electrode 13 and an acceleration electrode 14 for adjusting the radiation amount of the electron beam, and a main lens for focusing the electron beam on the screen The condenser electrode 15 and the anode 16 for ultimately accelerating the electron beam are arranged inline, and the condenser electrode is divided to form a constant voltage on one of the divided focus electrodes, and a constant voltage is applied to the other focus electrode. In the electron gun for a color cathode ray tube in which the shape of the outer electron beam through-hole of the electrode in which the dynamic quadrupole lens is formed between the divided focusing electrodes when the variable voltage is synchronized with the deflection current is applied, the variable voltage focusing electrode 40 A single electron beam through hole 31 is formed in the fixed voltage focusing electrode 30 on the opposite surface, and outer electron beam through holes 33a and 33c are asymmetrical in the fixed voltage focusing electrode. A guide inner electrode 32 is fixed, and a plurality of electron beam through holes 41a, 41b, 41c are formed in the variable voltage focusing electrode 40 opposite to the fixed voltage focusing electrode 30, and the electron beam is formed. The horizontal flat electrode 42 of the correction electrode is fixed to the fixed voltage focusing electrode 30 by fixing the correction electrode 43 having the plate-shaped horizontal flat electrode 42 protruding in the vertical direction with respect to the flat surface above and below the through hole. Since it is inserted into the electron beam through hole 31 formed in the), it is possible to improve the dynamic voltage difference between the three electron beams at the periphery of the screen, which has been eliminated by applying a large amount of voltage in the conventional method, even with the conventional equivalent voltage alone.

Description

Electron gun for colored cathode ray tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to an electron gun that scans an electron beam toward a fluorescent surface applied to an inner surface of a panel in a large TV or high definition industrial monitor.

1 is a partial longitudinal sectional view showing a schematic configuration of a general color cathode ray tube, in which red, green, and blue phosphors are applied to an inner surface of a panel 1 to form a fluorescent film 2, and to the rear of the panel 1; The funnel 3 in which the electron gun 4 is sealed to the neck portion 3a is fused to maintain a high vacuum inside.

A shadow mask 6, which serves as color screening of the electron beam 5 emitted from the electron gun 4, is fixed to the support frame 7 at a portion adjacent to the fluorescent film 2 coated on the inner surface of the panel 1. And a deflection yoke 8 is installed on the outer circumferential surface of the funnel to deflect the electron beam emitted from the electron gun in a vertical or horizontal direction.

The stem 9 is fixed to the rear of the electron gun, that is, the end of the neck portion 3a to be exposed to the outside, so that a voltage is applied to each electrode of the electron gun through a plurality of stem pins 10 fixed to the stem. .

2 is a schematic view showing the structure of a conventional electron gun, wherein the electron gun is composed of a triode and a main lens unit.

The three poles include three cathodes 12 each having a heater 11 as a heat source and are arranged side by side horizontally independently of each other, and a control electrode 13 disposed to maintain a predetermined distance from the cathode to control hot electrons generated from the cathode. And an accelerating electrode 14 arranged to maintain a predetermined distance from the control electrode and to accelerate and accelerate hot electrons gathered on the electron emitting material surface (not shown) of the cathode.

The main lens unit is composed of a focusing electrode 15 and an anode 16 for focusing and finally accelerating the electron beam generated in the triode.

The control electrode 13 is grounded, a low voltage of about 500 to 1000 V is applied to the acceleration electrode 14, a high voltage of about 25 to 35 KV is applied to the anode 16, and a positive voltage is applied to the focusing electrode 15. An intermediate voltage corresponding to 25 to 35% is applied.

In the conventional electron gun configured as described above, an electrostatic lens is formed between them by a potential difference applied to the focusing electrode 15 and the anode 16 as a predetermined potential is applied to each electrode. The light is focused by the electrostatic lens while passing through the focusing electrode 15 and the anode 16 and then focused at the center of the fluorescent surface.

At this time, the deflection yoke 8 with horizontal and vertical deflection coils is operated to deflect the electron beam 5 focused on the center of the fluorescent screen in the horizontal or vertical direction of the entire area of the screen, that is, the fluorescent screen.

In a color cathode ray tube using an inline type electron gun, since blue, green, and red phosphors are regularly arranged on a fluorescent surface, a self-concentrating type using a non-uniform magnetic field to concentrate the three electron beams 5 at one of the fluorescent surfaces. The deflection yoke (8) of convergence type is applied.

As shown in FIGS. 3A and 3B, the distribution of the magnetic field generated in the deflection yoke 8 to which the self-focusing type is applied is a pin cushion type, and the vertical deflection field is a barrel. The shape prevents misconvergence at the periphery of the fluorescent surface and simultaneously deflects the electron beam in the horizontal and vertical directions by Fleming's left hand law.

However, as illustrated in FIGS. 3C and 3D, the above-described horizontal and vertical deflection magnetic fields can be described by dividing into two-pole and four-pole components, which serve to deflect the electron beam in the horizontal and vertical directions. In addition, the 4-pole component focuses the electron beam in the vertical direction and diverges in the horizontal direction, so that the vertical electron beam is focused at a shorter distance than the horizontal electron beam so that the vertical direction of the electron beam rises convexly on the screen. It causes a halo phenomenon, which leads to deterioration of image quality.

4A and 4B show more specifically how distortion of the electron beam spot appears on the screen.

4A and 4B, since the electron beam spot is exactly circular in the center of the screen because it is not influenced by the deflection magnetic field, it is diverged in the horizontal direction as described above, and overconcentrated and distorted in the vertical direction. Since the high-density horizontal core 17 and the up-and-down halo 18 which is a low density up-and-down phenomenon generate | occur | produce, it acts as a cause to reduce the resolution in the periphery of a screen.

FIG. 5A shows the principle that the electron beam spot represented by the deflection yoke generates astigmatism without being focused at the periphery of the screen.

Even if the magnetic field is close to the uniform magnetic field, the spot of the electron beam is distorted by astigmatism due to the minute pin cushion or the barrel magnetic field. Do.

This problem is more severe when the cathode ray tube is large or the deflection angle is larger, which is one of the problems that must be solved in consideration of the tendency of consumers who prefer large cathode ray tubes and the increasing deflection angle depending on the size of the cathode ray tube. .

In order to solve the above problems, the four-pole component is generated by the electron gun to cancel the four-pole component generated by the self-focusing deflection yoke 8 so that the electron beam components in the horizontal and vertical directions can be simultaneously focused at one point.

That is, in order to form a four-pole lens, the focusing electrode 15 is divided into a first focusing electrode 19 and a second focusing electrode 20, and a dynamic 4-pole electrode is provided between the electrodes to form a 4-pole electrode. Astigmatism can be corrected by generating a potential difference to form a quadrupole lens.

However, the electron beam 5 is focused in front of the screen at the periphery due to the difference in electron beam movement distance between the center of the screen and the periphery.

Therefore, to solve this problem, when the electron beam 5 is deflected to the periphery of the screen, the electrostatic lens is controlled by applying a dynamic voltage (variable voltage) synchronized with the deflection frequency to weaken the power of the main lens and to adjust the focusing distance of the electron beam. The method of correcting the astigmatism of is mainly adopted.

Referring to Figures 6 to 8 shown in a conventional embodiment briefly described astigmatism correction means as follows.

6 to 8 show astigmatism correction means disclosed in U.S. Patent No. 5,061,881 of Matsushita, Japan.

Looking at the configuration, three square electron beam through holes 19a, 19b, 19c are formed in the first focusing electrode 19 and three squares are formed in the second focusing electrode 20 in a horizontal shape. By forming electron beam through holes 20a, 20b, and 20c, and forming a quadrupole lens therebetween, astigmatism is corrected at the periphery of the screen.

That is, the electron beam 5 generated at the triode, which is the electron beam forming region, passes through the first focusing electrode 19 and the second focusing electrode 20, which are divided, and is focused on the main lens, thereby forming an image on the screen. .

In particular, when the electron beam 5 is deflected to the periphery, the voltage (static voltage) applied to the first focusing electrode 19 is fixed constantly, but the voltage (dynamic voltage) applied to the second focusing electrode 20 is Since it is applied in a changed state in synchronization with the amount of deflection of the electron beam, the 4-pole lens is operated by the 4-pole electrode.

In general, the larger the cathode ray tube or the larger the deflection angle, the higher the voltage applied to the second focusing electrode 20 is than the voltage applied to the first focusing electrode 19.

The voltage applied to the second focusing electrode 20 is supplied in a parabola waveform in a circuit of a TV or a monitor, and is generally applied at about 300 to 1000 V higher than the voltage applied to the first focusing electrode 19.

That is, when a voltage is applied to the second focusing electrode 20, a quadrupole lens is formed due to a difference between the voltage applied to the first focusing electrode 19 and the voltage applied to the second focusing electrode 20. Since the shape of the electron beam spot is changed into an elongated shape, it acts in the direction of improving the halo 18, which is the upper part of the periphery generated by the non-uniform magnetic field of the deflection yoke through the main lens.

5B is a conceptual diagram illustrating a principle in which the path of the electron beam is corrected to match the focal point of the peripheral part when the quadrupole lens is used, and astigmatism of the deflection yoke by the quadrupole electrode is maintained with the same focusing force of the main lens. Indicates the state of compensation.

The quadrupole lens focuses in the horizontal direction by the diverging force in the horizontal direction by the deflection yoke, and the quadrupole lens diverges in the vertical direction by the amount of focus in the vertical direction by the deflection yoke.

To this end, a main lens weakening component (dynamic voltage) is required, which serves to cause the electron beam to be focused at an arbitrary position of the periphery as shown in FIG. 5B to coincide in both horizontal and vertical directions.

In this way, the proper four-pole lens and the dynamic voltage can ensure that the electron beam has an optimal focusing force at the periphery of the screen.

However, such a conventional electron gun does not correct a fine halo phenomenon (Fig. 9B) due to a deflection force difference (Fig. 9A) between an electron beam deflected from the outside and an electron beam deflected from the inside of the three electron beams. Fine halo size: B 〈G 〈R, if left of screen Fine halo size: R 〈G 〈B)

In the case of a deflection yoke using a non-uniform magnetic field, the deflection force becomes stronger toward the periphery (FIG. 9A), whereby the three electron beams generate a difference in deflection force for each of them, thereby causing a path difference for each of them. Since it is impossible to correct, there was a problem that a fine halo is generated in the periphery.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem in the related art, and an object thereof is to improve a resolution at a periphery of a screen by correcting astigmatism according to a deflection force of an electron beam.

According to an aspect of the present invention for achieving the above object, a three-pole portion consisting of an electron radiating means for emitting an electron beam, a control electrode and an acceleration electrode for adjusting the radiation amount of the electron beam, and a main lens for focusing the electron beam on the screen A focusing electrode to be formed and an anode for ultimately accelerating the electron beam are arranged inline, and the focusing electrode is divided to form a constant voltage applied to a focusing electrode on one side of the divided focusing electrodes and synchronized with a deflection current to the focusing electrode on the other side. An electron gun for a color cathode ray tube having a symmetrical outer electron beam passing hole shape of an electrode in which a dynamic quadrupole lens is formed between the divided focusing electrodes when a variable voltage is applied, the fixed voltage focusing electrode on the opposite surface of the variable voltage focusing electrode. A single electron beam through hole is formed and an outer electron beam passes through the fixed voltage focusing electrode. The asymmetric guide inner electrode is fixed, and a plurality of electron beam through holes are formed in the variable voltage focusing electrode on the opposite side of the fixed voltage focusing electrode, and protrude in the vertical direction with respect to the flat surface above and below the electron beam through hole. An electron gun for a color cathode ray tube is provided, wherein a correction electrode having a plate-shaped horizontal plate electrode is fixed so that the horizontal plate electrode of the correction electrode is inserted into an electron beam through hole formed in the fixed voltage focusing electrode.

1 is a partial longitudinal cross-sectional view showing a schematic configuration of a general color cathode ray tube;

2 is a schematic view showing the configuration of a conventional electron gun

3A to 3D illustrate distortions of electron beam spots due to non-uniform magnetic field of the self-focusing deflection yoke.

3A is a distribution diagram of a pin cushion type horizontal deflection magnetic field

3b is a distribution diagram of a barrel-type vertical deflection magnetic field;

3C is an exploded explanatory diagram of the dipole and quadrupole components of the pincushioned horizontal deflection magnetic field;

3D is an exploded explanatory diagram of the dipole and quadrupole components of the barrel-type vertical deflection magnetic field;

Figure 4a is a view showing the shape of the distorted electron beam spot on the conventional color cathode ray tube screen

4B is a view showing a shape in which an electron beam spot is distorted by a deflection magnetic field.

5A is a schematic diagram showing astigmatism and electron beam trajectory caused by deflection yoke

5B is a schematic diagram showing an electron beam trajectory when a four-pole lens is applied.

6 is a longitudinal sectional view showing conventional astigmatism correction means;

FIG. 7 is a front view of the first focusing electrode shown in FIG. 6. FIG.

FIG. 8 is a front view of the second focusing electrode shown in FIG. 6. FIG.

9A to 9D are views illustrating fine halo phenomena due to a difference in deflection force of an electron beam.

10 is a longitudinal sectional view showing the main part of the present invention;

11 is a front view of a fixed voltage focusing electrode applied to the present invention;

12A and 12B are perspective views of a correction electrode applied to the present invention

13A to 13D are front views illustrating one embodiment of a guide inner electrode applied to the present invention.

14a to 14d is a front view showing another embodiment of a guide inner electrode applied to the present invention

Explanation of symbols for main parts of the drawings

13 control electrode 14 acceleration electrode

15: focusing electrode 16: anode

30: fixed voltage focusing electrodes 31, 33a, 33b, 33c: electron beam through hole

32: guide inner electrode 40: variable voltage focusing electrode

42: horizontal flat electrode 43: correction electrode

Hereinafter, the present invention will be described in more detail with reference to FIGS. 10 to 14 as an embodiment.

FIG. 10 is a longitudinal sectional view showing the main part of the present invention, FIG. 11 is a front view of a fixed voltage focusing electrode applied to the present invention, and FIGS. 12A and 12B are perspective views of a correction electrode applied to the present invention. Parts identical to those of the electron gun are omitted in the description and given the same reference numerals.

As shown in FIG. 11, a first focusing electrode 30 (hereinafter referred to as a “constant voltage focusing electrode”) 30 on the opposite surface of the second focusing electrode (hereinafter, referred to as a “variable voltage focusing electrode”) 40 is provided as a single unit. An electron beam through hole 31 is formed, and a guide inner electrode 32 having three electron beam through holes 33a, 33b, 33c is inserted and fixed inside the fixed voltage focusing electrode 30.

The outer electron beam through holes 33a and 33c formed in the guide inner electrode 32 have an elongated rectangular shape.

That is, the electron beam through holes 33a, 33b, 33c formed in the guide inner electrode 32 have a trapezoidal shape (FIG. 13A), a pentagonal shape (FIG. 13B), a polygonal shape (FIG. 13C), Keyholes formed in a trapezoidal shape (FIG. 13D) or the like including a circular shape, or extended in the horizontal direction in the center of each polygonal electron beam passing hole 33a, 33b, 33c as shown in FIGS. 14A to 14D shown in another embodiment. The same characteristics are exhibited even when configured in a shape.

In addition, a plurality of electron beam passing holes 41a, 41b, 41c are formed in the variable voltage focusing electrode 40 on the opposite surface of the fixed voltage focusing electrode 30, and a flat surface is formed on the upper and lower portions of the electron beam passing hole. A square plate correction electrode 43 having a horizontal flat electrode 42 protruding from the cathode 12 perpendicular to the is fixed.

The electron beam through holes 44a, 44b, 44c formed in the correction electrode 43 may be circular or quadrangular.

In one embodiment of the present invention, the correction electrode 43 has a cross-sectional shape of "C" as shown in FIG. 12A. However, as shown in another embodiment, the horizontal flat electrode 42 of the correction electrode 43 is It may be configured to be bent inward toward the electron beam through holes 44a, 44b, 44c.

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

The quadrupole lens is operated by a potential difference when the fixed voltage is about 300 to 1000 V lower than the variable voltage, and the quadrupole lens is corrected by the astigmatism generated when the electron beam emitted from the cathode 12 is deflected toward the periphery of the screen. A magnetic field is generated to correct astigmatism.

Therefore, the voltage of each part (Center, Top, Edge, Corner) of the screen is measured in a state where the astigmatism correcting means does not operate, that is, in a non-dynamic state.

Here, the non-dynamic state refers to a state in which voltages of the same magnitude are simultaneously applied to the fixed voltage focusing electrode 30 and the variable voltage focusing electrode 40.

In this way, when measuring the voltage of each part of the screen in the non-dynamic state, the horizontal focus voltage at each point remains almost constant, but the focus voltage in the vertical direction changes exponentially in the order of center, top, edge, and corner. It can be seen.

Therefore, a corresponding quadrupole lens should be constructed to improve the aberration component of the deflection yoke.

At this time, each of the electron beam through holes 33a, 33b, 33c of the guide inner electrode 32 of the fixed voltage focusing electrode 30 constituting the quadrupole lens has a close relationship in improving the aberration component of the deflection yoke. Have

In other words, the larger the vertical long hole, which is the electron beam passing hole, the stronger the quadrupole lens is, and the smaller the smaller, the proportionally weaker the smaller is.

However, since the path difference is generated between the three electron beams in the electron gun, deflection occurs between the deflections (Fig. 9C), the conventional quadrupole lens cannot control such fine astigmatism (Fig. 12B).

That is, when the electron beam is deflected in the right direction, the electron beam on the right side has a fine deflection yoke astigmatism under the action of a stronger deflection force (Fig. 12A).

Therefore, the present invention cancels the micro deflection yoke astigmatism generated when the electron beam is deflected outward by asymmetrically forming the electron beam through holes 33a and 33c through which the outer electron beam passes in the guide inner electrode 32 for the improvement. Since the quadrupole lens is configured by different amounts of symmetry, the astigmatism of the outer electron beam is canceled out.

In addition, when a voltage of 300 to 1000 V is applied to the variable voltage focusing electrode 40 more than the fixed voltage focusing electrode 30, the peripheral convergence error due to the convergence force of the outer electron beam generated may be prevented.

The greater the vertical width of the outer electron beam through holes 33a and 33c formed in the guide inner electrode 32, the greater the overconvergence, and in the opposite case, the overconvergence.

In order to improve the above problems, the action force is controlled by making the vertical widths of the outer electron beam through holes 33a and 33c formed in the guide inner electrode 32 asymmetric.

On the other hand, when the horizontal flat electrode 42 formed on the correction electrode 43 to be bent inward as shown in Figure 12b according to another embodiment of the present invention because the action force becomes larger in the vertical direction, the conventional fixed voltage focusing Stronger quadrupole lenses can also be constructed with electrodes.

As described above, the present invention provides an electron beam of the guide inner electrode 32 fixed to the fixed voltage focusing electrode 30 against the occurrence of minute astigmatism of the deflection yoke with respect to the outer electron beam of the variable voltage focusing electrode of the conventional electron gun. Since the through-holes 33a and 33c are longitudinally asymmetrical to improve the fine halo generated at the periphery of the screen, the same applied voltage can be maintained at each point of the three electron beams.

Accordingly, it is possible to solve the misconvergence of the periphery of the screen without any additional device, and the dynamic voltage difference between the three electron beams in the periphery of the screen, which is required to apply a large amount of voltage in a conventional manner in a shape suitable for reducing the dynamic voltage in recent years. Can be improved only by the conventional equivalent voltage.

Claims (4)

An electron radiating means for radiating an electron beam, a tripolar portion comprising a control electrode and an acceleration electrode for controlling the radiation amount of the electron beam, a focusing electrode forming a main lens for focusing the electron beam on a screen, and an anode for ultimately accelerating the electron beam. Arranged in-line, the focusing electrode is divided to form a constant voltage on one of the divided focusing electrodes and a variable voltage in synchronization with a deflection current is applied to the focusing electrodes on the other side. In an electron gun for a color cathode ray tube having a symmetrical outer electron beam through hole of an electrode on which a dynamic quadrupole lens is formed, a single electron beam through hole is formed in a fixed voltage focusing electrode on the opposite surface of the variable voltage focusing electrode, The inner inner electron beam through hole is fixed to the guide inner electrode asymmetrical, the fixing A plurality of electron beam through holes are formed in the variable voltage focusing electrode on the opposite side of the pressure focusing electrode, and a correction electrode having plate-like horizontal flat electrodes protruding in the vertical direction with respect to the flat surface above and below the electron beam through holes is fixed. Electron gun for color cathode ray tube, characterized in that the horizontal plate electrode of the correction electrode is inserted into the electron beam through hole formed in the fixed voltage focusing electrode. The method of claim 1, An electron gun for a color cathode ray tube, characterized in that the outer electron beam passing hole positioned asymmetrically to the left and right of the guide inner electrode has a polygonal shape having an area projecting toward the center electron beam passing hole side. The method of claim 2, The electron beam passing hole is a electron gun for a color cathode ray tube, characterized in that the central portion is formed in a keyhole shape extending in the horizontal direction. The method of claim 1, The horizontal flat electrode of the correction electrode fixed to the variable voltage focusing electrode is bent inward toward the electron beam through hole, the electron gun for color cathode ray tube.