KR0142849B1 - Electron gun for color cathode ray tube - Google Patents

Abstract

The present invention discloses an electron gun for a color cathode ray tube.

The present invention relates to an electron gun for a color cathode ray tube, comprising a cathode, a control electrode, and a screen electrode forming a transposition triode, and first, second, third, and fourth focus electrodes and a final acceleration electrode forming a main lens system. The eccentric distance between the three electron beam through holes of the focus electrode is shorter than the eccentric distance between the three electron beam through holes formed on the incident side surface of the third focus electrode, and a focus voltage is applied to the first and third focus electrodes. A constant voltage lower than a focus voltage is applied to the two focus electrodes, and a dynamic focus voltage synchronized with a deflection signal is applied to the fourth focus electrode when the focus voltage is a base voltage. It has the advantage of improving the characteristics.

Description

Electron gun for colored cathode ray tube

1 is a sectional view showing a conventional electron gun for a cathode ray tube, showing a method of applying a voltage to each electrode.

2 is a sectional view showing the electron gun for the color cathode ray tube according to the present invention, showing a voltage application method.

* Explanation of symbols for main parts of the drawings

21: cathode 22: control electrode

23: screen electrode 24: first focus electrode

27: dynamic focus electrode 28: final acceleration electrode

S1, S2: eccentric distance (of electron beam passing space)

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube with improved convergence characteristics for converging electron beams on both sides to a central electron beam side.

In general, a cathode ray tube forms a pixel by electron beams emitted from an electron gun enclosed in its neck portion being selectively deflected by deflection yokes according to the dice and landing on a fluorescent film formed on the inner surface of the panel. Will form. Therefore, in order to form a clearer image, it is important to ensure that the electron beam emitted from the electron gun is accurately landed on the fluorescent point of the fluorescent film.

However, the cathode ray tube emits three electron beams emitted from the electron gun in-line so that the electron beams on both sides may not be accurately landed in the electron beam passing holes of the shadow mask having color selection, and the electron beams are deflected by the deflection yoke. When it is deflected to the periphery of the fluorescent film, it is influenced by the uneven deflection magnetic field of the deflection yoke, and the electron beam spots landing on the fluorescent film are distorted by the geometric curvature of the inner surface of the panel, so that the fluorescent point of the fluorescent film cannot be accurately landed. There was a problem.

In order to solve such a problem, conventionally, the cross section of the electron beam emitted from the electron gun is distorted in the reverse direction of the nonuniform magnetic field effect of the deflection yoke, and the focal length of the electron beam is scanned into the center of the fluorescent film and when scanned into the periphery. In addition to varying the size of the three electron beams, a method of converging the electron beams on both sides of the three electron beams to the center electron beam side has been sought.

Figure 1 shows an embodiment of a conventional electron gun for color cathode ray tube to solve the above problems.

This forms the cathode 11, the control electrode 12, and the screen electrode 13, and the auxiliary and main lens systems forming the pre-triode, the focus electrode 14, the dynamic focus electrode 15, and the final acceleration electrode 16. And electron beam passing holes formed at both ends of the final acceleration electrode 16 in an outward direction from the center of both electron beam passing holes 15R and 15B formed at the emission side of the dynamic focus electrode 15. Eccentric

A predetermined potential is applied to each of the electrodes, and a constant voltage VS is applied to the screen electrode 13, and a focus voltage VF higher than the constant voltage VS is applied to the focus electrode 14. A dynamic focus voltage VD is applied to the dynamic focus electrode 16 as the base voltage and is synchronized with a deflection signal, and the final acceleration electrode 16 has a higher voltage than the voltages. Voltage VE is applied.

In the conventional cathode ray tube electron gun 10 configured as described above, the focus voltage VF and the same voltage are applied to the dynamic focus electrode 15 when the electron beam emitted from the cathode 11 is scanned to the center portion of the fluorescent film. A prefocus lens is formed between the 13 and the focus electrode 14, and a main lens is formed between the dynamic focus electrode 15 and the final acceleration electrode. The dynamic focus electrode 15 and the final acceleration electrode 16 are formed. The main lenses formed by the electron beam through processing 15R, 15B, 16R, and 16B on both sides thereof are asymmetrical because their centers are eccentric with each other.

Accordingly, the electron beam emitted from the cathode 11 is focused and accelerated in the prefocus lens and the main lens to be landed on the fluorescent film. The electron beam formed by the two electron beam passing holes 15R, 15B, 16R, and 16B is provided. Since is formed asymmetrically, the electron beams of both sides passing through it are converged to the electron beam side of the center. When the electron beam emitted from the cathode 11 of the electron gun is deflected to the periphery of the fluorescent film, a dynamic focus voltage VD in synchronization with the deflection signal is applied to the dynamic focus electrode 15, thereby causing the focus electrode 14 and the dynamic focus. The potential difference between the electrodes 15 becomes small and relatively weak. Therefore, the electron beam emitted from the cathode is finally focused and accelerated by the electron lens formed between each electrode, so that the fluorescent film is landed on the periphery.

However, the electron gun 10 may reduce the overall spherical aberration and improve the focus characteristic of the electron lens by applying the dynamic focus voltage VD to the dynamic focus electrode 15, but the dynamic focus may be applied to the dynamic focus electrode 15. As the voltage VD is applied, the potential difference between the final accelerating electrode 16 decreases and the strength of the main lens formed therebetween is weakened, thereby reducing the convergence characteristics of the electron beams on both sides.

In order to solve such a problem, conventionally, a control electrode constituting a triode and an outer electron beam passing hole of the screen electrode are shifted so as to converge both electron beams, but there is a problem in that the accuracy of assembly of the electron gun cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide an electron gun for color cathode ray tubes, which can prevent the intensity of the main lens from being deteriorated by the application of a dynamic focus voltage, thereby reducing the convergence characteristics of the electron beam. have.

Another object of the present invention is to provide an electron gun for a color cathode ray tube that can improve the precision according to the assembly of the electrode.

In order to achieve the above object, the present invention provides a cathode electrode for a color cathode ray tube comprising a cathode, a control electrode, and a screen electrode forming an anterior triode, and first, second, third, and fourth focus electrodes and a final acceleration electrode forming a main lens system. To

The eccentric distance between the three electron beam through holes of the second focus electrode is shorter than the eccentric distance between the three electron beam through holes formed on the incident side surface of the third focus electrode.

Another aspect of the present invention is a color cathode ray tube electron gun provided with a cathode, a control electrode and a screen electrode forming a pre-triode, a first, a second, a third focusing electrode and a final accelerating electrode forming a main lens system.

The eccentric distance between the three electron beam through holes of the second focus electrode is shorter than the eccentric distance between the three electron beam through holes formed on the incident side surface of the third focus electrode.

A focus voltage is applied to the first and third focus electrodes, a constant voltage lower than a focus voltage is applied to the second focus electrode, and a dynamic focus synchronized with a deflection signal when the focus voltage is a base voltage to the fourth focus electrode. Voltage is applied.

In the present invention, it is preferable to apply a constant voltage between the screen electrode and the coin to the second focus electrode.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows an electron gun for a color cathode ray tube according to the present invention, which comprises a cathode 21, a control electrode 22 and a screen electrode 23, and an auxiliary lens and a main lens. 1,2,3 focus 24,25,26, dynamic focus electrode 27, and final acceleration electrode 28 are comprised. Here, the eccentric distance S1 between the centers of the three electron beam through holes 25R, 25G and 25B formed in the second focus electrode 25 is three electron beam through holes 26R formed in the third focus electrode 26 ( 26G) is formed shorter than the eccentric distance S2 of 26B.

A predetermined voltage is applied to each electrode of the electron gun, which will be described below.

A constant voltage VS is applied to the screen electrode 23, a focus voltage VF higher than the constant voltage VS is applied to the first and third focus electrodes 25 and 26, and the dynamic focus electrode 27 is applied to the screen electrode 23. The focus voltage VF is a base voltage, and a dynamic focus voltage VD synchronized with a deflection signal is applied, and an anode voltage VE higher than the voltage is applied to the final acceleration electrode 28.

Referring to the operation of the electron gun for the color cathode ray tube according to the present invention configured as described above are as follows.

In the electron gun 20 for the color cathode ray tube according to the present invention, when a predetermined voltage is applied to each of the electrodes as described above, a prefocus lens is formed between the screen electrode 23 and the first focus electrode 24. An auxiliary lens is formed between the third focus electrode 26 and the dynamic focus electrode 27 according to whether a dynamic focus voltage VD is applied, and a main lens is formed between the dynamic focus electrode 27 and the final acceleration electrode 28. The electrostatic lens is formed.

Therefore, the electron beams emitted from the cathode 21 of the electron gun 20 are landed at each fluorescent point of the fluorescent film after passing through the electrostatic lenses, which will be described below.

First, when the electron beam emitted from the cathode 21 is scanned onto the fluorescent film, the dynamic focus voltage VD synchronized with the deflection signal is applied to the dynamic focus electrode 27 so that the electron beam is selectively applied according to the dice. An auxiliary electron lens is selectively formed between the focus electrode 24 and the dynamic focus electrode 27. Therefore, the electron beam emitted from the cathode 21 is preliminarily focused and accelerated by a prefocus lens formed between the screen electrode 23 and the first focus electrode 24, and then the dynamic focus electrode 27 It is finally focused and accelerated by the main electrostatic lens formed between the final accelerating electrodes 28 to be scanned at the center of the fluorescent film, and between the centers of the electron beam through holes formed on the emission side surface 25B of the second focus electrode 25. Since the two eccentric distances S1 are formed to be shorter than the eccentric distances S2 between the centers of the electron beam passing holes formed in the third focusing electrode 26, the kettle lenses on both sides formed therebetween are asymmetrically formed, Since many spherical aberrations are received, the electron beams on both sides are converged to the center electron beam side and landed at the best state in the entire fluorescent film. As described above, the electron gun for the color cathode ray tube of the present invention can prevent a convergence drift caused by the application of the dynamic focus voltage emitted from the cathode, and further improve the resolution of the cathode ray tube employing the same.

In addition, in the present invention, since the convergence of the three electron beams is made on the side adjacent to the cathode, the efficiency can be improved compared to the convergence in the main lens, and the eccentric distance between the centers of the electron beam passing holes of the focus electrode is different. As a result, the assembly precision of the electron gun can be improved.

Claims (3)

In the electron gun for a color cathode ray tube comprising a cathode, a control electrode and a screen electrode forming a pre-triode, a first, a second, a third focusing electrode and a final accelerating electrode forming a main lens system, the three focusing electrodes of the second focus electrode An electron gun for a color cathode ray tube, characterized in that the eccentric distance between the electron beam through holes is shorter than the eccentric distance between three electron beam through holes formed on the incident side of the third focus electrode. In the electron gun for a color cathode ray tube comprising a cathode, a control electrode and a screen electrode forming a pre-triode, a first, a second, a third focusing electrode and a final accelerating electrode forming a main lens system, the three focusing electrodes of the second focus electrode The eccentric distance between the electron beam through holes is shorter than the eccentric distance between three electron beam through holes formed on the incident side of the third focus electrode, a focus voltage is applied to the first and third focus electrodes, and a second focus electrode is applied to the second focus electrode. A constant voltage lower than a focus voltage is applied, and a dynamic focus voltage synchronized with a deflection signal is applied to the fourth focus electrode when the focus voltage is a base voltage. The electron gun for a color cathode ray tube according to claim 1, wherein the second focus electrode is applied on the screen electrode and the coin.