JPS60175342A - Electron gun for cathode-ray tube - Google Patents

Abstract

PURPOSE:To sufficiently enlarge the opening hole diameter of an auxiliary electrode for simply forming a long-focusing lens by providing an auxiliary electrode between two electrodes forming the main lens part while supporting each electode with an insulating supporter divided into two parts by the auxiliary electrode. CONSTITUTION:The electron gun for a color picture tube is formed of a cathode 9, the first and second grids 11, 12 the third and fourth grids 13, 14 composed of two cup-shaped electrodes, a convergence electrode 15 and an auxiliary electrode 16 located between the grids 13, 14 and having a large opening while supporting and assembling each electrode with the insulating supporters 2a and 2b divided into two parts by the auxiliary electrode 16. Accordingly, the other undesired electric field inside the neck can be screened while making the required electric field at the electron lens part not to be disturbed by impressing the potential of about the middle value between those of grids 13 and 14 upon the auxiliary electrode 16, thus being able to form an electron lens with the same high performance as when the distance between the grids 13 and 14 is enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electron gun for a cathode ray tube for focusing at least one, preferably more, electron beams, and in particular to its electrostatic lens structure and electrode support structure. It is.

[Technical background and problems of the invention]

A cathode ray tube is equipped with at least one electron gun, and this electron gun forms an electron beam spot on a predetermined target. One of the extremely important factors that determines the performance of the cathode ray tube in this electron gun is the spot diameter of the electron beam on the target. It goes without saying that a smaller spot diameter on the target is more desirable, but this spot diameter is determined by the performance of the electron gun. Generally, an electron gun consists of a part that generates an electron beam and a main lens part that accelerates and focuses the electron beam.One effective means of improving the performance of an electron gun is to improve the performance of the main lens part.

Most of the main lens parts are electrostatic lenses, which are formed by arranging a plurality of electrodes having openings coaxially and applying a predetermined potential. There are several types of electrostatic lenses such as this, depending on the electrode configuration, but basically, the electrode aperture diameter is increased to form a large-diameter lens, or the distance between the electrodes is lengthened to form a gradual lens. Lens performance can be improved by changing the electric potential and forming a long focal length lens. However, since cathode ray tube electron guns are generally enclosed in a thin glass cylinder called the neck,
First, the aperture of the electrodes, that is, the lens aperture is physically limited, and then the distance between the electrodes is limited in order to prevent the focused electric field formed between the electrodes from being influenced by other electric fields. In particular, when multiple electron guns are used in a line, such as in a color picture tube, the smaller the distance between the electron guns (8g/J), the easier it is to converge the multiple beams, and the deflection power is also reduced. It's advantageous. Therefore, the openings in the electrodes have to be made even smaller.

Therefore, while keeping the electron gun spacing (8 g) small, the electrode aperture is made as large as possible to widen the distance between the electrodes, and an auxiliary electrode is provided between the electrodes to shield the influence of the undesired electric field on the inner wall of the neck. An electron gun is considered. In such an electron gun, the aperture diameter of the auxiliary electrode must be set sufficiently large in order to eliminate the influence of the electric field of the auxiliary electrode. Therefore, we would like to make the aperture diameter of the auxiliary electrode as large as the inner wall of the neck to make the distance between the electrodes sufficiently wide and create a high-performance electron gun, but in reality, the aperture diameter of the auxiliary electrode should be made as large as the inner wall of the neck. Therefore, the distance between the electrodes cannot be made sufficiently wide. This is because the insulating support for supporting the electrode is enclosed in the neck like the electrode, and the aperture diameter of the auxiliary electrode is actually limited by the distance between the insulating supports.

[Purpose of the invention]

In the cathode ray tube electron gun having the above structure, the present invention enables the aperture diameter of the auxiliary electrode to be increased to the aperture diameter limited by the inner wall of the neck, thereby sufficiently increasing the distance between the electrodes and improving the lens performance of the main lens. The purpose of this is to further reduce the diameter of the spot focused on a predetermined target.

[Summary of the invention]

The electron gun for a cathode ray tube according to the invention achieves the above object by having a structure in which an insulating support for supporting an electrode is separated from the auxiliary electrode of the electron gun having the above structure.

[Embodiments of the invention]

The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an example of an electron gun for a color picture tube embodying the present invention, FIG. 2(a) is a sectional view along the Y-Z axis of FIG. FIG.

In FIGS. 1, 2(a), and 2(b), the electron gun (1) has several electrodes for nuclei, which will be described later, and complex insulating supports (za) and (2) that support them. The plurality of electrodes have three electron beams A that strike the red, green, and blue phosphor layers (not shown) of the phosphor surface as targets.
Three heaters (6a), (6b), (6c) that generate (3a), (3b), (3C)
(9a) ) (9b)
, (9c), the first grid αυ, the second grid αυ, the third grid α3, and the fourth Grid α, convergence electrode αω
and an auxiliary electrode αe which is located between the third grid Qal and the fourth grid α and has one large opening, and is stacked and fixedly supported on the insulating supports (2a) and (2b). . The first grid (11) and the second grid housing 2 are plate-shaped electrodes arranged close to each other, and the third grid a3 is composed of two cup-shaped electrodes WA( 23a) Formed as t(23b), the fourth grid α has two cup-shaped electrodes (z4a) arranged and joined at a predetermined distance from the third grid.
24b), and the convergence electrode a is one cup-shaped electrode (25a) fixed by welding to the fourth grid α.
). Three circular electron beam passage holes aligned with each electron beam are provided on the bottom surface of the cup-shaped electrode and the flat plate electrode of each grid electrode and convergence electrode, respectively. The electron beam passage holes in the first grid αυ and the second grid α4 are relatively small □, and the electron beam passage holes on the side facing the second grid U of the third grid α3 (33a) s (33b) + (33
c) is larger than that, and the electron beam passage hole (43a) on the side facing the third grid (the fourth grid α in [3]
(43b), (43C) and the electron beam passage holes (34a), (34b) in the fourth grid.

(a4c), (44a), (44b) + (44c) have the same diameter and relatively large diameter, and the convergence electrode (15
) electron beam passing holes (35a), (35b),
(35C) is a small size. #Auxiliary electrode alH-
1 m2 cylindrical electrodes (26a), (26b) are formed, these electrodes are located in the third grid and the fourth grid respectively.
Gritsu)' (14) cup-shaped electrode (23b), (2
One such auxiliary electrode containing 4a) is shown in FIG. Further, a pulp spacer α force is attached to the convergence electrode (15) which applies a high voltage of approximately 25 KVO to the anode terminal (not shown). Such an electron gun is enclosed within the neck of a thin glass cylinder. A stem bin α is arranged at the bottom of the neck.This stem bin α supports and fixes the electron gun (1), and also connects the convergence electrode (1) to the outside through the stem bin 4 to transmit the potential of each electrode other than the fourth grid I. It is now available for supply.

In the above electrode configuration, from the heater to the third grid a
4 and one of the auxiliary electrodes (26a) are implanted and fixedly supported by a pair of insulating supports (2a), and the other electrode (26b) of the auxiliary electrodes and the fourth grid (14) are Two electrodes (26a), which are auxiliary electrodes, are implanted and fixedly supported by another pair of insulating supports (2b).

(26b) is the 7th rank part (30a), (30b
), and the joint is fixed by welding to form the electron gun (1). Therefore, as shown in FIG. 1, the diameter of the auxiliary electrode tte is not limited by the diameter DB of the pair of insulating supports, but can be maximized until it is limited by the inner wall diameter DN of the neck. .

Now, the operation of the above electron gun is as follows, for example.

The cathode (9) is kept at a cut-off voltage of approximately 150V, to which a respective modulation signal is applied. Ground potential is applied to the first grid I, approximately 700V is applied to the second grid I,
Approximately 6.5 KV is applied to 3rd grid σ island, and 4th grid I
An anode high voltage of about 25 KV is applied to the auxiliary electrode αe.
Approximately 16 KV, which is approximately the middle potential between the third grid potential (131 potential and the fourth grid α potential), is applied to the electron lens having such an electrode structure in the main lens portion. (a) and Fig. 3 (b). Fig. 3 (a) corresponds to Fig. 2 (a), and Fig. 3 (b) corresponds to Fig. 2 (b). Equipotential lines are shown, and a simplified electrode structure is shown to explain the main lens part of this electron gun.
As can be seen from Fig. 3(b), the potential distribution is hardly disturbed in the 9 portions (inside the dotted line in the figure), which are approximately equivalent to the openings of the third grid α3 and the fourth grid (to), which determine the diameter of the electron lens. , as shown in Figure 4, is equivalent to the state in which the distance between the two cylindrical electrodes is simply increased, without being affected by the surrounding electric field. Therefore, the axial potential distribution becomes slightly gentler as shown in FIG. 5, the electro-optical magnification by this electron lens is reduced, and the spherical aberration coefficient is also reduced, so that the lens performance is significantly improved.

As shown in Figure 4, simply increasing the distance between the two electrodes is not practical because, as mentioned above, the potential distribution is affected by other electric fields within the neck. However, as in the present invention, at least one auxiliary electrode having a diameter as large as the diameter of the electron lens is disposed between two electrodes, and a potential approximately midway between the two electrode potentials is applied to this auxiliary electrode. By doing so, it is possible to shield other undesired electric fields within the neck and prevent the necessary electric field of the electron lens from being disturbed. An electronic lens with equivalent high performance can be formed.

At this time, the auxiliary electrode only needs to have one large hole, and unlike other electrodes, three electron beam passing holes are not required, so the three holes should be made larger without changing the distance between their centers. Even if this is not possible, the performance of the electron lens can be improved very easily by increasing the distance between the electrodes.

In the color picture tube electron gun of the above embodiment, three electron beams must be converged at one point on the shadow mask or screen (target), and several methods are known for this purpose. That is, there are a method of tilting and arranging the electron guns themselves on both sides, a method of tilting the main lenses or other electron lenses on both sides, and a method of forming an asymmetric lens. Although these conventional methods can be used as they are in the present invention, the convergence can also be achieved by changing the structure of the auxiliary electrode. That is, as shown in FIGS. 7(a) and 7(b), by making the X-direction diameter DX4 on the fourth grid side of the auxiliary electrode smaller than the X-direction diameter DX3 on the third grid side, the electrons on both sides are Convergence is achieved by slightly deflecting each beam toward the central electron beam. This is because in the X-Z axis cross section, the potential of the auxiliary electrode on the fourth grid side penetrates into the stain part more than the potential of the auxiliary electrode on the third grid side, and this potential becomes the average at that position. Electron beams on both sides (3a) because the potential is lower than υ.

This is because (3C) receives force inward. Alternatively, as shown in FIG. 8(a) and FIG. 8(bl), two auxiliary electrodes (16-1) with insulators (60) adhesively fixed to the 7-rank parts (30a) and (30b) of the auxiliary electrodes, (16-2)
The potential of the auxiliary electrode (16-2) on the fourth grid a4) side is applied to these auxiliary electrodes at a potential approximately midway between the potential of the third grid (31) and the potential of the fourth grid (b). For the same reason, the above convergence can also be achieved by slightly lowering the potential of the auxiliary electrode (16-1) on the grid (131 side).At this time, the electrode lengths of the two auxiliary electrodes are also adjusted by appropriately varying them. It's okay.

A ceramic plate is suitable as the insulator (60), and a polyimide adhesive with excellent heat resistance and voltage resistance is suitable as the adhesive. 7(a) and 8(a) are the same <y-z axis cross sections as in FIG. 2, and FIG. 7(b)
and FIG. 8(b) respectively show X-Z axis cross sections.

In the embodiment described above, the potential of the auxiliary electrode is supplied from the outside through the stem pin, but the present invention is not limited to this, and the potential may be supplied by resistance division. For example, as shown in FIG.
2) and a resistor (54) coated with glass (53).
) are respectively installed behind the insulating supports (2a) and (2b) that support each electrode of the electron gun (1), and installed behind the insulating support (2b) on the 4th grid aa side. The resistor (54b) has one end connected to the convergence electrode (
1ω to apply an anode high voltage Bb, one side is connected to the auxiliary electrode (26b), and the resistor (54a) is installed behind the insulating support (2a) on the third grid (13 side).
Connect one side to the auxiliary electrode (26a), connect the other side to the stem pin a9, and connect it to the ground voltage (55), low voltage source (56), or resistor (57) externally, and auxiliary the appropriate position. Connect to the electrode. With such a configuration, the electrical configuration is as shown in FIG. 11, and the auxiliary electrode and the third grid are supplied with a voltage divided by the resistor of the anode high voltage Bb.

As such resistors (54a) and (54b), resistors used as a method for supplying the electrode potential of the electrostatic convergence adjustment electrode in color picture tubes are suitable.

In the embodiment shown in FIG. 10, the resistor is in the form of a single plate and is installed behind the insulating support, but the present invention is not limited to this, and the resistive material may be applied directly behind the insulating support. Needless to say, the insulating support itself may be used as a resistor.

If the auxiliary electrode potential is supplied by resistor division as described above, there is no need to supply a medium-high voltage auxiliary electrode potential at the stem portion, and the withstand voltage reliability around the stem portion is improved.
We can provide polarized ray tubes that are practical. Furthermore, if the third grid potential is also supplied by resistor division, the withstand voltage reliability around the stem will be further improved, and the third grid can be controlled at a low potential via the stem pin, allowing dynamic It becomes easy to adjust the focusing state of the electron lens.

Furthermore, the main lens portion of the above embodiment is basically a bipotential lens consisting of two electrodes, the third grid and the fourth grid, and has an auxiliary electrode having a large aperture between the electrodes. However, the present invention is not limited to this, and may be based on a 22 potential type lens as shown in FIG. 12(a), or may be based on a geodora potential type lens as shown in FIG. 12(b). Okay, 12th
The essence of the present invention does not change even if a beriodic potential type lens is used as the basis, as shown in Figure (C), or other tripotential type lenses are used as the basis. FIG. 12(a) to FIG. 12(C) show schematic configuration diagrams of the main lens portion, in which auxiliary electrodes are arranged in each portion where an electron lens is formed and the present invention is applied. It goes without saying that the present invention may be applied only to the main electronic lens section. In particular, Figure 12(b),
In the lens system shown in Figure (C) K, the voltage of the third grid G3 can be set to about 8 to 9 KV, so the quality of the electron beam from the object point formation part can be used in the best condition, and the overall performance of the electron gun is It gets even better.

Further, in the above embodiment, three electron guns are integrated in a row in the horizontal direction, but the present invention is not limited to this. It goes without saying that the present invention can be applied to a structure in which several electron guns are arranged or a single electron gun structure.

〔Effect of the invention〕

As described above, according to the present invention, one auxiliary electrode larger than these electrodes is arranged between two opposing electrodes, and the auxiliary electrode and the two electrodes are each fixedly held by an insulating support, and this insulating support By using a cathode ray tube electron gun with a structure in which the body is divided into two parts by an auxiliary electrode part, and the two electrodes are fixed via the auxiliary electrode, the aperture diameter of the auxiliary electrode part is limited by the inner diameter of the neck. It can be made large enough. In addition, by applying an intermediate potential between the two opposing electrodes, the distance between the two opposing electrodes can be set sufficiently large, and a long focal length lens with a substantially long distance between the electrodes can be formed without any practical problems. can be done. The cathode ray tube electron gun of the present invention has a simple structure and is easy to manufacture.Therefore, it is possible to provide a highly practical and high performance electron gun for cathode ray tubes.

In addition, in the electron gun of the present invention, a high-performance electron gun can be obtained without increasing the beam spacing between multiple electron beams, that is, the distance between the electron beam passing holes, so that it is possible to obtain a high-performance electron gun with less deflection power and high convergence quality in a color picture tube. It can be used as a high-performance electron gun.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the present invention, and is a side sectional view of an electron gun for a color picture tube, and FIGS. 2(a) and 2(b) are i
Figure 1 oy-zs and x-z axis imi, Figure 3 (a),
3(b) and 4 are equipotential line distribution diagrams for explaining the present invention, and FIG. 3(a) and 3(b) are diagrams of FIG. 2(a) and 2(b). Fig. 4 is a sectional view of the coaxial cylindrical lens, Fig. 5 is an axial potential distribution diagram in Fig. 4, and Fig. 6 is used in the actual example shown in Fig. 1. A perspective view of the electrode, FIG. 7(a). FIG. 7(b), FIG. 8(a), and FIG. 8(b) show other embodiments of the present invention.
), Fig. 7(b) and Fig. 8(b) are the same.
z@, a cross-sectional view along the x-z axis, Fig. 9 is a cross-sectional view showing a part of the resistor, Fig. 10 is an embodiment of the present invention when the resistor shown in Fig. 9 is used, Fig. 11 are the electrical configuration diagram of Fig. 10, Fig. 12(a), Fig. 12(b), Fig. 12(C)
FIG. 3 is a side sectional view showing another embodiment of the present invention. (1)... Electron gun (2a), (2b)... Insulating support (3a), (3b), (3c:) - Electron beam (13
1...Third grid (14)/Fourth grid αω/
・Convergence electrode 1F...Auxiliary electrodes (54a), (54b)...Resistor agent Patent attorney Kensuke Chika (and 1 other person) Figure 1 Figure 2 Figure 3 Figure C (L) Figure 4 Figure 6 Figure 7 (θ) (6) Figure 8 (α) (b) Figure 10

Claims (1)

[Claims] An electron gun comprising at least an electron beam generating section and a main lens section for focusing the electron beam onto a predetermined target, the main lens section being connected to at least two opposing electrodes each having an electron beam passing hole. at least one auxiliary electrode located between the electrodes and having an aperture larger than the electron beam passage hole of these electrodes, each of the electrodes being fixedly held by an insulating support; , a shield made of a king lens portion having a structure in which a relatively low potential and a relatively high potential are applied to the two opposing electrodes, and a relatively intermediate potential is applied to the auxiliary electrode. , An electron gun for a cathode ray tube, in which the distribution edge support is separated from the front 6 auxiliary electrodes along the direction in which the electron beam travels.