KR100255667B1 - Electron gun for color cathode ray tube - Google Patents

Abstract

PURPOSE: An electron gun is provided to improve a resolution degree by improving a convergence property and a focus property for landing three electron beams on one fluorescence point. CONSTITUTION: An electron gun(20) has a cathode(21), a care electrode(22), a screen electrode(23), the first to fourth focus electrodes(24,25,26,27), and the last acceleration electrode(28). Each of the first to fourth focus electrodes(24,25,26,27) consists of an electron lens of an uni-potential type and a tetrode lens. The last acceleration electrode(28) is installed adjacent to the fourth focus electrode(27) and consists of a main lens comprising a focus lens and a conveyer lens. A rim(30) is formed at an edge of an outer side of an electron beam transmitting hole of an electrode, which is placed at a cathode side among electrodes consisting of the tetrode lens. The rim is extended toward an electrode forming the main lens.

Description

Electron gun for colored cathode ray tube

1 is a cross-sectional view of an electron gun for a conventional color cathode ray tube.

FIG. 2 shows the electrodes forming the quadrupole lens shown in FIG.

2 (a) is a front view showing the emission side of the fifth focus electrode,

2 (b) is a front view showing the incident side surface of the sixth focus electrode.

3 is a view showing the horizontal lens of the quadrupole lens formed by the fifth and sixth focus electrodes shown in FIG.

4 is a sectional view showing a state in which an electron beam is converged by the electron gun shown in FIG.

5 is a sectional view showing a color cathode ray tube according to the present invention.

FIG. 6 illustrates an electrode forming a quadrupole lens among the electrodes shown in FIG.

6 (a) is a front view showing the emission side of the fifth focus electrode,

6 (b) is a front view showing the incident side surface of the sixth focus electrode.

7 (a) and 7 (b) are front views showing another embodiment of the electrode forming the quadrupole lens of the electron gun according to the present invention;

8 is a view showing the quadrupole lens formed by the electrode shown in FIG.

9 is a view showing the state in which the quadrupole lens is formed by the electrode shown in FIG.

10 is a sectional view showing a state in which an electron beam of an electron gun is converged according to the present invention.

* Explanation of symbols for main parts of the drawings

21: cathode 22: control electrode

23: screen electrode 24: first focus electrode

25: second focus electrode 26: third focus electrode

27: fourth focus electrode 28: final acceleration electrode

30: Rim VF: Focus voltage

VD: Dynamic Focus Voltage

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electron gun for an inline type cathode ray tube with improved convergence characteristics so that an electron beam emitted from each electron gun arranged in an inline type can be landed at one fluorescent point. will be.

Typically, the electron gun for the color cathode ray tube is installed in the neck portion of the cathode ray tube to emit hot electrons, and the performance of the cathode ray tube depends on the state in which the electron beam emitted from the electron gun is landed on the fluorescent film. Therefore, many electron guns have been developed so that the electron beam emitted from the electron gun can be accurately landed at the fluorescent point of the fluorescent film.

Figure 1 shows an example of such an electron gun.

This is the first, second, third and fourth focusing electrodes 5 and 6 which are sequentially arranged adjacent to the cathode 2, the control electrode 3 and the screen electrode 4, which form the front triode, and form an auxiliary electrostatic lens. (7) (8) and the final acceleration electrode (9) which is provided adjacent to the fourth focus electrode (8) to form a main electron lens, the emission side of the fourth focus electrode (8) The electrode constituting the final accelerating electrode 9 and the electrode member positioned in the outer electrode members 8a and 9a formed with the large-diameter electron beam passing holes 8H and 9H through which the three-electron beams pass together, and three independent electrodes And the inner electrode members 8b and 9b formed with the small-diameter electron beam passing holes 8H 'and 9H', and are shown on the incident side of the fourth focus electrode 8 as shown in FIG. 2 (a). As shown in Fig. 2, a horizontal electron beam through hole 8H ″ is formed, and on the exit side of the third focus electrode 7, the length is extended as shown in Fig. 2 (b). Of the electron beam passage hole (7H) is formed. And a predetermined potential is applied to each electrode constituting the electron gun, which will be described below. A constant voltage VS is applied to the screen electrode 4 and the second focus electrode 6, and a focus voltage VF relatively higher than the constant voltage VS is applied to the first and third focus electrodes 5 and 7. A dynamic focus voltage VD is applied to the fourth focus electrode 8 in synchronization with a deflection signal, and a high-voltage enowood voltage VE is applied to the final acceleration electrode 9. <VF≤VD <VE)

In the conventional color cathode ray tube electron gun configured as described above, a predetermined potential is applied to each electrode to form an electrostatic lens and scan each fluorescent point of the electron beam fluorescent film emitted from the cathode 2. When divided into when injected into the peripheral and when described as follows.

First, when the electron beam emitted from the electron gun is scanned to the center portion of the fluorescent film, the dynamic focus voltage VD which is approximately equal to the focus voltage VF is applied to the dynamic focus electrode 8. Therefore, a unpotential electrostatic lens is formed on the first, second, and third focus electrodes 5, 6, and 7, and the bi-potential auxiliary electron is formed between the fourth focus electrode 8 and the final acceleration electrode 9. A lens is formed. The bipotential electrostatic legs are formed of large diameter electron beam through holes 8H and 9H and independent small diameter electron beam through holes formed in the external electrodes 8a, 9a and 8b, 9b. 8H ') and 9H' form a convergence lens for landing the focus lens and the three electron beams on one fluorescent point.

Therefore, the electron beam emitted from the cathode 2 is pre-focused and accelerated by the unipotential auxiliary electron lens, and then focused and converged by the focus lens and the convergence lens of the main lens and landed at the center of the fluorescent film. Will be.

When the electron beam emitted from the electron gun is scanned at the periphery of the fluorescent film, the dynamic focus voltage VD is applied to the fourth focus electrode 8 as the base voltage and is synchronized with the deflection signal. An auxiliary electron lens is formed between the first, second and third focus electrodes 5, 6 and 7, and the quadrupole lens is formed on the third and fourth focus electrodes 7 and 8, as shown in FIG. 3. A main lens having a focus lens and a convergence lens is formed between the fourth focus electrode 8 and the final acceleration electrode 9. Therefore, the electron beam emitted from the cathode 2 is preliminarily focused and accelerated by the auxiliary electron lens and the quadrupole lens as shown in FIG. 4, and then the focus lens 110 and the converger of the main lens 100 are accelerated. The convergence and convergence of the final lens by the presence lens 120 is to be scanned to the periphery of the fluorescent film 200. The main lens including the focus electrode and the convergence lens has a small potential difference between the focus electrode 8 and the final acceleration electrode 9 as the dynamic focus voltage VD is applied to the fourth focus electrode 8. The intensity of the main lens becomes relatively weak, and as a result, the focus lens 110 and the convergence lens 120 of the main lens 100 become relatively weak. As a result, the electron beam passing through the beam does not have sufficient focusing and convergence as shown by the dotted line in FIG. 4, and thus the electron beam is not rendered to the best state of the periphery of the fluorescent film 200. There was a problem. As a result, since the size of the electron beam spot to be rendered on the entire fluorescent film is different at each portion of the fluorescent film, there is a problem that the resolution of an image obtained by being excited by the electron beam cannot be improved.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the color cathode ray which can improve the resolution and focus characteristic of the three electron beams emitted from the cathode to the one fluorescent point is improved, so that the image can improve the resolution. The purpose is to provide a light gun.

In order to achieve the above object, the present invention provides a cathode, a control electrode, and a screen electrode forming a transposition triode, and a plurality of focus electrodes, a focus lens, and a convergence lens forming a unipotential type electron lens and a quadrupole lens. In the electron gun for a color cathode ray tube having a plurality of electrodes constituting the lens, the electrode side for forming the main lens on the outer edge of the outer electron beam through hole of the electrode of the electrode constituting the quadrupole lens located on the cathode side or its It is characterized by the fact that the rim is formed to extend a predetermined length on the opposite side.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 5 shows a color cathode ray tube electron gun 20 according to the present invention, which includes a cathode 21, a care electrode 22, a screen electrode 23, a unipotential type electron lens, First, second, third and fourth focus electrodes 24, 25, 26 and 27 forming a quadrupole lens and adjacent to the fourth focus electrode 27 include a focus lens and a conveyor lens. And a final accelerating electrode 28 constituting the main lens. As shown in FIG. 4, an elongated electron beam through hole 26R, 26G, 26B is formed in the emission side 26a of the third focus electrode 26 constituting the quadrupole lens. On the incidence side surface of the four focus electrodes 27, horizontal electron beam passing holes 27R, 27G and 27B are formed. In addition, an electron beam passing hole 26R located at an outer side of the three electron beam passing holes 26R, 26G and 26B arranged inline in the incident side surface 26a of the third focus electrode 26. A rim 30 which protrudes a predetermined length toward the fourth focus electrode 27 is formed at an outer edge of the 26B). Here, the rim 30 is formed on both sides of the edge of the outer electron beam through hole as shown in FIG. 7, but preferably forms a higher height of the rim 30 ′ formed on the outer side.

In addition, the exit side electrode member and the final acceleration electrode 28 of the focus electrode 27 forming the main lens having the focus lens and the convergence lens, the external electrode member 27a having the common large-diameter electron beam passing hole 27H formed therein. And internal electrode members 27b and 28b which are positioned inside 28a and the external electrode members 27a and 28a and are formed with three independent electron beam through holes 27H 'and 28H'.

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

A ground voltage is applied to the control electrode, a constant voltage VS is applied to the screen electrode 23 and the second fork electrode 25, and a focus higher than the constant voltage is applied to the first and third focus electrodes 24 and 26. A voltage VF is applied to the fourth focus electrode 27 and a parabolic type dynamic focus voltage VD is applied to the fourth focus electrode 27 in synchronization with the output current of the deflection yoke. ) Is applied. (VS <VF≤VD <VE)

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.

First, as a predetermined potential is applied to an electrode forming the color cathode ray tube electron gun, a universal potential auxiliary electron lens is formed between the first, second and third focus electrodes 24, 25 and 26, and the third and fourth A quadrupole lens is selectively formed between the focus electrodes 26 and 27 according to the scanning position of the electron beam scanned on the fluorescent film, and the focus lens and the cone between the fourth focus electrode 27 and the final acceleration electrode 28. A main lens having a version lens is formed. As described above, in the electron lens formed between the electrodes, the intensity of the electron lens, the lens formation state, and the convergence state of the electron beam vary depending on the position of the electron beam scanning, and the electron beam is scanned at the center of the fluorescent film. When divided into when injected into the peripheral and explain as follows.

First, when the electron beam emitted from the electron gun is scanned to the center portion of the fluorescent film, the dynamic focus voltage VD which is about the same as the focus voltage VF is applied to the fourth focus electrode 27 as in the related art. Accordingly, a unipotential type electrostatic lens is formed on the first, second and third focus electrodes 24, 25, and 26, and a bi-potential main lens is formed between the fourth focus electrode 27 and the final acceleration electrode 28. The bi-potential type electron lens has a large diameter electron beam through hole 27H and 28H formed on the external electrodes 27a, 28a and 27b, 28b and an independent small diameter electron beam through hole 27H. (28H ') forms a convergence lens for landing the focus lens and the three electron beams on one fluorescent point.

Therefore, the electron beam emitted from the cathode 2 is preliminarily focused and accelerated by the unipotential auxiliary electron lens, and then focused and converged by the focus lens and the convergence lens of the main lens so that it is optimal in the center of the fluorescent film. Landing in the state.

When the electron beam emitted from the electron gun is scanned at the periphery of the fluorescent film, a dynamic focus voltage VD is applied to the fourth focus electrode 27 as a base voltage and synchronized with a deflection signal. An auxiliary electron lens is formed between the first, second and third focus electrodes 24, 25 and 26, and a quadrupole lens is formed on the third and fourth focus electrodes 26 and 27 and the fourth focus electrode. Between the 27 and the final acceleration electrode 28, a main lens having a focus lens and a convergence lens is formed. Herein, the electron lens formed between the third focusing electrode 26 and the fourth focusing electrode 27 has an electron lens formed between the electron beam passing holes as shown in FIGS. 8 and 9. The electron lens has a rim 30 formed outside the edges of the outer electron beam through holes 26R and 26B formed on the emission side of the third focus electrode 26 or an outer rim formed relatively long at the edges of the outer electron beam through holes. Therefore, it is formed asymmetrically.

Accordingly, the electron beam emitted from the cathode 21 passes through the quadrupole lens after preliminary focusing and acceleration while passing through the auxiliary electron lens, as shown by a dotted line in FIG. 10. The electron beam passing through the electron beam passing valleys 26R, 27R, 26B, and 27B is converged to the center portion of the main lens, that is, the electron beam side in the center. The converged electron beam passes through the focus lens 110 and the convergence lens 120 of the main lens 100. In the main lens 100, the fourth focus electrode 27 has a dynamic focus voltage. Since the potential difference becomes relatively small and weakened by the application of (VD), the amount converged by the quadruple lens is compensated for the weakness of the main lens so that it cannot be converged. Will be.

As described above, the electron gun for the color cathode ray tube of the present invention is relatively weakened by applying the dynamic focus voltage to the focus electrode forming the fourth focus electrode forming the main lens, thereby fundamentally resolving the deterioration of the convergence characteristic. It has the advantage of improving the resolution of an electron gun for a cathode ray tube.

Claims (3)

And a plurality of electrodes comprising a cathode, a control electrode, and a screen electrode forming an anterior triode, a plurality of focus electrodes forming a unipotential type electron lens and a quadrupole lens, and a main lens forming a focus lens and a convergence lens. An electron gun for a colored cathode ray tube, wherein a rim extending a predetermined length to an electrode side forming a main lens is formed at an outer edge of an outer electron beam through hole of an electrode located on a cathode side of the electrodes constituting the quadrupole lens. Electron gun for colored cathode ray tubes. The electron gun for a color cathode ray tube according to claim 1, wherein the rim is formed at both sides of the outer electron beam passing hole and the rim located at the outer side is elongated. The electron gun for a color cathode ray tube according to claim 1, wherein the electron beam through hole of the electrode forming the quadrupole lens is a longitudinal electron beam through hole and a horizontal electron beam through hole.