JPH024094B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the main electron lens constituent electrode of an in-line color picture tube electron gun.

The resolution characteristics of an electron gun are mainly limited by the spherical aberration of the electron lens, and in order to obtain high resolution characteristics, the conventionally used bi-potential focus type consisting of two main electron lens electrodes, or the conventionally used bipotential focus type consisting of two main electron lens electrodes, or three main electron lenses are used. The spherical aberration of the electron lens can be reduced by constructing a multistage focusing electron lens by appropriately combining uni-potential focusing electron lenses made of electrodes, or by increasing the aperture of the electrodes constituting the main electron lens. It is.

For the former, there is a multistage focusing electron lens in which the main electron lens is composed of four electrodes, G3 electrode to G6 electrode, as shown in FIG. 1, for example. That is, the electron gun assembly 1 consists of three cathode assemblies 1 arranged in a row in the same plane, insulated from each other and kept at equal distances S.
0, a G1 electrode 11 which is an electrically common control electrode and a G2 electrode 12 which is an acceleration electrode, which are arranged in sequence in the electron beam traveling direction opposite to this, electrically,
Common in structure, each electron beam path consists of an integrated electrode forming a substantially independent electron lens.
It is composed of G3 electrode 13 to G6 electrode 16. G4
Electrode 14 and G6 electrode 16 are connected to feeder line 1 (not shown)
The G3 electrode 13 and the G5 electrode 15 are connected to the same potential by a power supply line 17B (not shown), and the anode voltage E _B of high voltage is supplied by the high voltage anode voltage E B from the stem power supply pin (not shown). A focusing voltage V _F of approximately 20 to 40% of the
5. The electron beam is sequentially focused in three stages by the main focusing lens formed in the gap between the G5 electrode 15 and the G6 electrode 16. Therefore, it is possible to gradually focus the electron beam with three main electron lenses, and it is possible to focus the electron beam with a single main lens like the conventional bi-potential focus type or uni-potential focus type. Since the strength of each electron lens can be made weaker than in the case where the main electron lens is used, it is possible to reduce the spherical aberration of the main electron lens. in this case
Let L ₀ be the axial length of the G3 electrode 13 to G6 electrode 16.

On the other hand, for the latter, the main electron lens electrode aperture is limited to the inner diameter of the glass neck of the color picture tube, and in an in-line color picture tube with three electron guns arranged in a row, the main electron lens electrode aperture is at most the inner diameter of the glass neck. The maximum diameter is less than 1/3, and it is important to approach this maximum diameter when designing the electrode structure. Figure 2 a, b
2A and 2B respectively show a top view and a side sectional view of an integrated in-line type electrode 2 formed based on the above idea. That is, the electrode 2 has central and both outer openings 21, 22, 23 with an aperture D, which are spaced at equal distances S from each other in a roughly oval-shaped closed surface 24, and has a cylinder side portion surrounding the closed surface 24. 25 and a flange-like edge 26 perpendicular to and around the cylindrical side portion 25. In this case, it has been conventionally believed that the ratio D/S of the diameter D of the central and outer openings to the distance between the openings is 0.84 or less to facilitate part molding.
As disclosed in No. 56-199825, the opening diameter D is made as close to S as possible by setting 0.88≦D/S≦0.98 to increase the diameter by a special parts processing method.

By arranging two electrodes in which the three large-diameter apertures described above are formed in the closed surface and facing each other and applying a predetermined voltage to both electrodes to form a main electron lens, the D/S
The spherical aberration of the electron lens can be made smaller than when ≦0.84.

Therefore, if a large-diameter electron lens is combined with the multi-stage focusing electron lens described above, the resolution can be greatly improved, but if large-diameter electrodes are simply applied to all stages of the multi-stage focusing electron lens, the electron gun structure will be significantly reduced. As a result, the overall length of the color picture tube becomes extremely long, and the electron gun assembly becomes very expensive. The reason for this is that if the operating conditions of the picture tube are the same, the ratio of the focusing voltage V _F to the anode voltage E _B , V _F /E _B, is constant, and in general, the focusing voltage V _F is proportional to the ratio of the main electron lens electrode length to the aperture diameter. Therefore, by increasing the diameter of all main electron lens apertures, all electrode lengths are similarly extended, and the electron gun structure becomes longer. In addition, since large-diameter electrodes are formed by special processing, electrode formation is difficult and requires extra molding processing than for electrodes with conventional electrode opening diameters of D/S≦0.84. becomes expensive.

Generally, the biggest drawback of color picture tubes over other display devices is their large depth dimension. Furthermore, changing the depth dimension of a device set cabinet in which a conventional color picture tube is used means remaking the cabinet, which incurs an enormous cost in remaking the molding die. Therefore, even if the resolution characteristics of the electron gun are improved, if the overall length of the electron gun becomes longer, the biggest drawback of the color picture tube will be exacerbated, and the overall length will become incompatible with the conventional color picture tube, and the set cabinet will become longer. The cost required for improvement would be enormous, making it extremely difficult to introduce a color picture tube with improved resolution characteristics. That is, an increase in the total length of the color picture tube becomes a serious problem.

The present invention has been made in view of the above-mentioned drawbacks.
The aperture diameter D of the final stage electron lens electrode located on the image receiving screen side of an in-line multi-stage focusing electron lens in which three or more electrodes are opposed to each other and a main electron lens is formed by two or more electrode gaps. The ratio to the mutual distance S of the three openings is made large with D/S≦0.88, and the other stages are made small with D/S≦0.84 to minimize the increase in the total length of the electron gun electrode structure and prevent an increase in the price of the electron gun structure. The object of the present invention is to provide an electron gun assembly that provides high resolution characteristics.

The present invention will be described in detail below with reference to the drawings.
In the following, for convenience of explanation, the same reference numerals are given to the same parts as those described above.

FIG. 3 shows a cross-sectional view of an in-line multi-stage focusing electron lens electrode assembly 3 showing an embodiment of the present invention, in which the electrode structures 3 are arranged in a line insulated from each other in the same plane and kept at equal distances S, not shown. Cathode structure 10
A G1 electrode 11, which is an electrically common control electrode, and a G2 electrode 12, which is an acceleration electrode, which are electrically and structurally common and arranged in order in the electron beam traveling direction, are electrically and structurally common and arranged in each electron beam path. consists of integrated electrodes forming essentially independent electron lenses.
G3 electrode 13, G4 electrode 14, and G5 electrode 35,
It is composed of a G6 electrode 36. G4 electrode 14 and G6
The electrodes 36 are connected to the same potential by a power supply line 37A (not shown), and a high voltage anode voltage E _B is supplied to them, and the G3 electrode 13 and the G5 electrode 35 are connected to the same potential by a power supply line 37B (not shown), not shown. A focused voltage V _F of about 20 to 40% of the anode voltage is supplied from the stem power supply pin, and the G3 electrode 13 and the G4 electrode 14, the G4 electrode 14 and the G5 electrode 35, and the G5 electrode 35
The electron beam is sequentially focused in three stages by a main focusing electron lens formed in the gap between the G6 electrodes 36. However, G3 electrode 13, G4 electrode 14, and G4 electrode 14
The diameter D ₀ of each opening in the opposing part of the G5 electrode 35 is D ₀ /S≦0.84
It has a relatively small value for the distance S between the holes, and the diameter of each hole in the opposing part of the G5 electrode 35 and the G6 electrode 36
D ₁ is larger than the distance S between the openings, where D ₁ /S≦0.89, and has a large diameter. Therefore, since the aperture diameter of the final stage electron lens located on the image receiving screen side is increased, the spherical aberration reduction effect of the multi-stage focusing electron lens and the low spherical aberration characteristic of the large-diameter electrostatic electron lens are synergistic. However, the spherical aberration of this electron lens is significantly reduced, and an electron lens with high resolution characteristics can be realized. Further, the electron beam flux emitted from the cathode 10 diverges after passing through the crossover point formed between the G1 electrode 11 and the G2 electrode 12, enters the main electron lens, and is made to have the minimum beam diameter on the image receiving screen. Although it is focused in the main electron lens, the incident electron beam bundle generally diverges and has its maximum diameter at the final electron lens stage, so even if the front two stages of electron lenses have small diameters, the influence of spherical aberration is comparatively small. The target is small. On the other hand, since the final stage electron lens, which occupies the maximum beam diameter, has a large diameter, the effect of increasing the diameter is effectively exerted. Furthermore, since increasing the aperture diameter is limited to the G5 electrode 35 and G6 electrode 36 on the side opposite to the G6 electrode 36, compared to the case where all electrode apertures of the G3 electrode 13 to G6 electrode 36 are increased in diameter, , the increase in electrode length can be limited to the G5 electrode only,
The value is approximately proportional to the rate of increase in the aperture diameter D ₁ /D ₀ .
Here, since the electrode length of the final stage G6 electrode 36 and the subsequent shielding magnetic pole etc. are also at the same potential as E _B , the penetration of the electron lens electric field formed between the opposing G5 electrodes 35 is not prevented. If within the range,
There is usually no change proportional to the aperture diameter.

Therefore, the axial length L ₁ from the lower end of the G3 electrode 13 to the upper end of the G6 electrode 36 of the electron gun assembly 3 is approximately equal to the axial length of the G5 electrode 35 compared to the corresponding axial length L ₀ of the conventional electron gun assembly 1. Opening diameter increase rate (D ₁ /D ₀ −1)
It just makes it longer. For example, in the conventional electron gun structure 1 with a focusing condition of V _F /F _B = 28% and S = 6.6 mm.
D ₀ = 5.5mm, G3, G4, G5, G6 electrode lengths are each 6.0
mm, 0.6mm, 11.5mm, 6.0mm, G3−G4, G4
-G5, G5-G6 electrode spacing is 1.2mm, 1.2mm, 1.0 respectively
mm, and therefore L ₀ =27.5 mm. However, if the opening diameters of the opposing parts of G3 to G6 electrodes are all increased to D ₁ = 6.3 mm without changing the electrode spacing, G3,
G4, G5, G6 electrode lengths are 7.5mm, 0.9mm, 14.0mm, respectively.
6.0mm, and L ₁ =31.8mm. On the other hand, according to the embodiment of the present invention, the G5 electrode length is 13.8 mm, and the other things remain unchanged, so L ₁ =29.8 mm. In other words, the increase in the electron gun length of the multi-stage focusing electron gun assembly by increasing the diameter of the main electron lens electrode aperture is L ₁ −L ₀ = 31.8 mm − 27.5 mm = 4.3 mm if all stages are increased in diameter. According to the invention, L ₁ −L ₀ =29.8mm−27.5mm=2.3mm.
Can be shortened by 2.0mm.

In other words, by limiting the enlargement of the electron lens aperture to the final stage, the increase in the total length of the electron gun assembly can be minimized compared to simply increasing the diameter of all stages, and the maximum length of the color picture tube can be minimized. In addition, the depth of the set cabinet in which conventional color picture tubes are used can be reduced by the total length of the color picture tube according to the present invention. Since the increase is small, there is no need to change it, and it is possible to easily make it interchangeable without incurring the huge expense required to change the depth of the cabinet.

On the other hand, in the present invention, the large-diameter electrodes, which are difficult to mold, are the G5 electrode on the side opposite to the G6 electrode, and the G6 electrode on the side opposite to the G6 electrode.
Since it can be limited to the two at the final stage of the electrode, G3
~Compared to the number of large-diameter electrodes required when all opposing surfaces of the G6 electrodes are made large in diameter, the increase in electrode prices for the electron gun assembly can be minimized.

As described above, according to the present invention, the diameter of the electrode aperture is made as close as possible to the distance between the apertures in the final stage of the multistage focusing electron lens to increase the aperture, so the overall length of the electron gun structure is not excessively large. The resolution characteristics can be significantly improved from low current to high current range of cathode emission current without significantly increasing the cost of the required components.

In the above description, the main electron lens structure was discussed in which medium-high voltage and high voltage were periodically applied to the four electrodes G3 to G6 in order, but the present invention is not limited to this, and A main electron lens to which a different potential is applied with an electrode, or a multistage focusing electron lens with three or more main electron lens electrodes can all be applied.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of an electron gun assembly equipped with a conventional in-line multi-stage focusing electron lens, Figures 2a and b are top and side sectional views of a large-diameter electrode assembly, respectively, and Figure 3 is a cross-sectional view of an electron gun assembly equipped with a conventional in-line multi-stage focusing electron lens. 1A and 1B respectively show cross-sectional views of an electron gun assembly equipped with an in-line multi-stage focusing electron lens according to an embodiment of the present invention. 10... Cathode structure, 11... G1 electrode, 12...
...G2 electrode, 13...G3 electrode, 14...G4 electrode,
15, 35... G5 electrode, 16, 36... G6 electrode, 21, 22, 23... Center and both outer openings of closed cylindrical body electrode, 24... Closed surface, 25... Cylinder side part, 26... ...flange rim.

[Claims]

1. In a color cathode ray tube device equipped with an in-line integrated electron gun and a convergence spirit magnet, the convergence spirit magnet is located near an electrode on the cathode side of two electrodes that face each other and form a main lens. a first pair of bipolar magnets for correcting the electron beam trajectory disposed in the
A second electrode for adjusting color purity is arranged near the electrode on the phosphor screen side of the two electrodes that face each other and form the main lens.
A color cathode ray tube device comprising a pair of two-pole magnets.