JPS636972B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-electron gun electrode structure for a color cathode ray tube that generates a plurality of electron beams. The present invention relates to an electron gun electrode assembly with an integrated electrode forming an electron lens.

In color cathode ray tubes, the assembly accuracy of the electron gun electrode structure has been improved for the purpose of self-centralization of convergence, and the assembly work has been simplified, or the diameter of the glass envelope neck where the electron gun is sealed has been reduced. As a means of reducing the volume occupied by the electron gun electrode structure, an in-line type electron beam is provided that is electrically and structurally common and has integrated electrodes that form substantially individual or common electron lenses in each electron beam path. Gun electrode structures are commonly used.

First, prior to explaining the present invention, we will explain the in-line electron gun of a conventionally used color cathode ray tube, which generates three electron beams in the same plane, with an electron gun electrode structure in which the main electron lens has a bipotential focus method. An example will be described in detail with reference to FIG.

That is, the electron gun electrode structures 1 are insulated from each other,
Three cathode assemblies 10R, 10G, 10B arranged in a line with equal distances S in the same plane, and a G1 electrode 11, a G2 electrode 12, and a G3 electrode arranged in sequence in the electron beam traveling direction opposite to this. 13.G4
Consisting of an electrode 14 and a bottomed cylindrical magnetic pole 15, each electrode except the magnetic pole 15 is embedded and fixed so as to be sandwiched between two insulator support rods 16 via an electrode supporter, and a predetermined electrode spacing is maintained. is held.
Each through hole 11R, 11G, 11 through which each electron beam of G1 electrode 11, G2 electrode 12, and G3 electrode 13 passes
B; 12R, 12G, 12B; 13R ₁ , 13G ₁ ,
13B ₁ ; 13R ₂ , 13G ₂ , and 13B ₂ are also aligned in a line with equal distance S, and the electron beam fluxes _BR , _BG , radiated from the three cathodes 10R, 10G, 10B of the cathode structure B _B is accelerated and focused so that it travels on parallel paths 18R, 18G, and 18B, which are the axes of the three electron guns. The distance S′ between the through holes of the G4 electrode 14 is somewhat larger than the above-mentioned S,
A so-called equivalent tilt lens is formed by an asymmetric electric field on both outer sides of the main electron lens formed in each corresponding electron beam hole gap between the G3 electrode 13 and the G4 electrode 14, and is arranged near the fluorescent surface of the cathode ray tube. The two outer electron beams B _R and B _B traveling in parallel at the center on the color selection mechanism (generally a shadow mask) are electrostatically concentrated on the central electron beam B _G side.

Here, the cross sections of the G3 electrode 13 and the G4 electrode 14 perpendicular to the electron gun axes 18R, 18G, and 18B correspond to the arrangement direction of the center and both outer electron beam holes, which are aligned and bored in a straight line within the closed end surface. The G3 electrode 13 is a closed cylindrical body with a substantially rectangular _or elliptical shape that is long and _short in the direction perpendicular to the arrangement direction _. A closed cylindrical part 13 _-1 in which the exit parts 13A _R , 13A _G , 13A _B are integrally formed, and the openings 13R ₂ , 13G ₂ ,
The closed cylindrical part _13-2 having _13B2 has its mouth edge overlapped.

In the operating state where a predetermined potential is applied to the electrodes of the electron gun electrode structure, each cathode 10R, 10G, 10B
The electron beam emitted from G1 electrode 11 and G2
The beam passes through each corresponding beam aperture in the electrode 12, and approximately
A crossover image is formed between the G1 electrode 11 and the G2 electrode 12, and after divergence, the G2 electrode 12 and the G3 electrode 13
_-1 independent 3 formed between each corresponding beam hole
The beam is prefocused by two pre-focus electron lenses L _p , and then the main electron lens L _M formed between the corresponding through holes of the G3 electrode 13 _-2 and the G4 electrode focuses the beam to the minimum beam cross section on the fluorescent surface. Focused to hold.

The above-described in-line electron gun electrode structure 1 has three cathodes 10R, 1 aligned in a straight line in the same plane.
Three electron beam bundles emitted from 0G and 10B
Since both outer _electron beams B _R , B _B are superimposed on _the central electron beam B _G on the color selection mechanism disposed near the fluorescent surface, _the central electron beam B _G
The electron beam travel paths of both outer electron beams B _R and B _B become longer. Furthermore, both outer electron beams B _R , B _B
passes through an equivalent tilted lens consisting of an asymmetric electric field due to the difference in the distance S between the axes of the main electron lens, so it receives a stronger focusing effect than the central electron lens. Therefore, the optimal concentration conditions for the center electron beam and both outer electron beams are different due to the difference in path. In other words, the state in which each crossover point on line C-C' in Figure 2A is focused on S-S' near the fluorescent surface by the pre-focus electron lens L _P and the main electron lens L _M is schematically shown. As shown in the equivalent optical model shown in the figure, the central electron beam B _G is optimally focused.
When the focusing voltage of the G3 electrode 13 is adjusted, both outer electron beams B _R and B _B become overfocused, and vice versa.
As shown in Figure 2, when the focusing voltage is adjusted so that both outer electron beams B _R and B _B are optimally focused, the central electron beam B _G becomes underfocused, and the focusing voltage at this time is lower than in the case of Figure 2 A. The central electron beam and both outer electron beams provide an optimal focusing state.
The focusing voltage values applied to the G3 electrode 13 are different.

This phenomenon is caused by the fact that as the distance S between the axes of the electron gun increases, the path difference between the center and both outer electron beams increases, and the asymmetry of the equivalent tilt lens increases in order to focus both outer electron beams onto the central electron beam. Therefore, the difference between the respective optimum focusing voltages becomes large. Therefore, the focusing voltage has to be adjusted between the optimal focusing voltages of the center and both outer electron beams, and neither the center nor both outer electron beams are in the optimal focusing state, and the reproduced image on the fluorescent surface is resolution was impaired.

The present invention eliminates the above-mentioned drawbacks and has three independent cathodes arranged in-line in the same plane and a plurality of electrodes sequentially arranged in front of the cathodes. In the electron gun electrode structure, which has three bulges integrally formed on the G3 electrode closing surface facing the G2 electrode, forming substantially separate electron lenses in the electron beam path, the two outer electron An in-line electron gun electrode for a color cathode ray tube that matches the optimum focusing conditions of the central and both outer electron beams on the fluorescent surface by setting the aperture diameter at the tip of the bulging part of the beam passage to be larger than that at the center. The purpose is to provide a structure.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a cross-sectional view showing the in-line color cathode ray tube electron gun electrode structure 2 of the present invention, which is insulated from each other and arranged at equal intervals S in the same plane, as in the conventional case.
three cathode assemblies 10R arranged in a line while maintaining
10G, 10B, and G1 electrode 11 and G2 electrode 1 which are arranged in sequence in the electron beam traveling direction opposite to these.
2. It is composed of a G3 electrode 23, a G4 electrode 14, and a magnetic pole 15, and each electrode other than the magnetic pole 15 is embedded and fixed in two insulator support rods via an electrode supporter to maintain a predetermined electrode spacing. There is. The distances between the three sets of electron beam holes formed in each electrode other than the G4 electrode are also aligned in a line while maintaining the above-mentioned equal distance S, and the distance S' between the holes of the G4 electrode 14 is the same as before. S
The gap between the G3 electrode 23 and the G4 electrode 14 corresponding to the electron beam holes forms an equivalent tilt lens due to the asymmetric electric field, and two outer electron beams traveling in parallel at the center of the shadow mask are formed. R _R and B _B are concentrated into the central electron beam B _G.

Here, the G2 of the G3 electrode 23 is constructed by overlapping two sets of closed cylindrical electrodes 23 _-1 and 23 _-2 at their mouth edges.
On the side facing the electrode 12, electron beam holes 23R ₁ , 23G ₁ ,
Three bulges 23A _R , 23A _G , with 23B ₁
23A _{and B} are integrally formed. However, the diameter _D 1 of the through holes 23R ₁ , 23B ₁ bored at the tips of both the outer bulges 23A _R and 23A _B is set larger than the diameter D ₀ of the through hole 23G ₁ of the central bulge 23A _G. . Therefore, when looking at the pre-focus lens electric field formed between the corresponding through holes of the G2 electrode 12 and the G3 electrode _23-1 , as shown in Fig. From the bulge A to the bulge 23A _R , A _B
The penetration of the electric field is promoted, the curvature is small and smooth, and the change in potential gradient is small. Therefore, the pre-focus lens L _P formed between the electron beam holes in the bulging parts of the integrated electrodes G2 electrode 12 and G3 electrode 23 _-1 becomes weaker at both outer sides than at the center. , the lens action on the paths of the outer electron beams B _R , B _B can be made weaker than before, and the paths of the outer electron beams B _R , B _B from the electron gun to the fluorescent surface of the cathode ray tube become central electrons. It is longer than the path of beam B _G , and the difference in optimal focusing conditions due to both outer main electron lenses being stronger than the central main electron lens is corrected by equivalent tilt lenses for concentrating the outer beam, and the optimal focusing conditions are made to match. I can do it.

In the in-line electron gun electrode assembly 2 according to the present invention equipped with an integrated electrode as described above, the path difference between the central electron beam B _G and both outer electron beams B _R and B _B from the electron gun to the fluorescent surface of the cathode ray tube is The optimum focusing conditions for the central and outer electron beams on the fluorescent surface can be perfectly matched due to the difference in intensity between the main electron lens and the main electron lens. That is, due to the above structural difference, conventionally, when the focusing voltage of the G3 electrode 23 is adjusted so that the central electron beam B _G is optimally focused, both outer electron beams B _R , B _B
However, since the pre-focus lenses formed on both outer electron beam paths are weaker than those on the central electron beam path, the central electron beam is completely optimized without overfocusing. It can be made to match the focused state.

According to an embodiment of the present invention, the in-line electron gun electrode structure with integrated electrodes can easily match the optimum focusing conditions of the center and both outer beams due to structural differences, so that the cathode ray tube fluorescent surface The resolution of the reproduced image above can be significantly improved.

In the above explanation, the electron gun electrode structure in which the main electron lens adopts a bipotential focus method has been described, but it goes without saying that the present application can be applied to main electron lenses of other methods.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an in-line electron gun electrode structure of a conventional color cathode ray tube, FIGS. 2A and B are equivalent optical model diagrams of the electron gun shown in FIG. 1, and FIG. 3 is an embodiment of the present invention. 4A and 4B, which are cross-sectional views of the in-line electron gun electrode structure based on the above, show the pre-focus electron lens electric field formed between the central and outer G3 electrode bulges and the G2 electrode. 10R, 10G, 10B... cathode structure, 11...
...G1 electrode, 12...G2 electrode, 13, 23...G3
Electrode, 14...G4 electrode, 18R, 18G, 18
B...Axis of the electron gun, B _R , B _B ...Both outer electron beams, B _G ...Central electron beam, 13A _R , 13A _G ,
13A _B , 23A _R , 23A _G , 23A _B ... bulges of the G3 electrode.

Claims (1)

[Claims] 1. It has three independent cathodes arranged in-line in the same plane and a plurality of electrodes arranged sequentially in front of the cathodes, and the electrodes used at the same potential are integrated to create a substantially individual cathode for each electron beam path. In the electron gun electrode structure that constitutes an electron lens and has three bulges integrally formed on the closed surface of the G3 electrode facing the G2 electrode, the diameter of the beam aperture at the tip of the two outer bulges is set to the center. This is an in-line electron gun electrode structure for color cathode ray tubes, which is characterized by being set larger than that.