JPH09199048A - Electron gun for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve position accuracy of an emission hole by improving a mounting structure of a plurality of grid electrodes included in a prefocus system of an electron gun for a color cathode-ray tube. SOLUTION: Each of a first/second grid electrode G1, G2 and additional grid electrode GM, included in a prefocus system, is divided into three parts, and mutually independent three cathode/prefocus compound units 5 are provided to be integrally assembled in a corresponding cathode 1. A mounting component including a connection member 12 is used, and the three cathode/prefocus compound units 5 are mounted by a prescribed tilt angle to be matched with an out-going angle of each electron beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun used for a color cathode ray tube. More specifically, the present invention relates to an integral mounting structure of a plurality of grid electrodes included in a prefocus system of an electron gun and three cathodes corresponding to the three primary colors of color.

[0002]

2. Description of the Related Art FIG. 3 shows an example of a conventional electron gun for a color cathode ray tube. This electron gun is a so-called one-gun-three-beam trinitron type, and particularly shows an electron gun incorporated in a highly accurate color CRT for computer displays. This electron gun includes three cathodes 1, a prefocus system 2 and a main lens system 3. The three cathodes 1 generate three electron beams corresponding to the three primary colors of RGB. The prefocus system 2 includes a plurality of grid electrodes and emits three electron beams at a predetermined emission angle. In this example, the prefocus system 2 is a normal first grid electrode G1.
In addition to the second grid electrode G2, an additional grid electrode GM for improving accuracy is provided. Each grid electrode G1,
Emission holes E1, E2 and EM for passing an electron beam are provided in G2 and GM, respectively. The main lens system 3 is located on the emission side of the prefocus system 2 and includes a third grid electrode G3, a fourth grid electrode G4, a fifth grid electrode G5, and the like.

In order to assemble this electron gun, first, the cathode 1 and each grid electrode G1, G2, GM are provided with inclination angles for determining the emission angles of three electron beams of RGB. Next, alignment is performed in the X-axis and Y-axis directions (directions intersecting with the electron beam) using guide holes that serve as a reference for positioning each grid electrode. Further, a spacer or the like having a predetermined thickness is inserted between each grid electrode to perform alignment in the Z-axis direction (electron beam direction), and the grid electrodes are pressed with a constant pressure from both ends. Finally, in this state, the grid electrodes are fixed to each other using bead glass or the like having a relatively small coefficient of thermal expansion.

[0004]

However, in the above-mentioned conventional assembling method, variations occur in the inclination angle and hole position of each grid electrode, and as a result, the spot characteristics of the electron beam deteriorate and cause defects. There is a problem. Specifically, due to variations in the guide holes provided in each grid electrode, springback before and after beading, etc.
The emission holes through which the electron beam passes will no longer line up in a straight line. Further, the surface angle of each grid electrode may not reach a desired value. Therefore, the path through which the electron beam passes is not stable, which leads to deterioration of spot characteristics.

[0005]

Means for Solving the Problems The following means have been taken to solve the above-mentioned problems of the conventional technique. That is, the electron gun for a color cathode-ray tube according to the present invention has, as a basic configuration, three cathodes that generate three electron beams corresponding to the three primary colors, and three grid electrodes at a predetermined emission angle. And a main lens system located on the emission side thereof. As a characteristic feature, each grid electrode included in the prefocus system is divided into three parts and integrally incorporated with the corresponding cathodes to provide three independent cathode / prefocus composites. Further, a mounting component for mounting the three cathode / prefocus composite bodies at a predetermined inclination angle according to the emission angle of the electron beam is provided. The mounting parts are, for example, a pair of substrate members commonly provided for the three cathode / prefocus composites, and three connecting members processed according to the inclination angles of the three cathode / prefocus composites. And each cathode / prefocus composite is attached to the substrate member via the connecting member. The prefocus system has, for example, a first grid electrode, a second grid electrode, and an additional grid electrode, and these three grid electrodes are each divided into three parts, which are integrally incorporated with the corresponding cathode. Configure individual cathode / prefocus composites.

According to the present invention, in an electron gun for a color cathode ray tube incorporated in a Trinitron CRT or the like featuring one gun and three beams, instead of using a grid electrode having a predetermined tilt angle in the prefocus system, an RBG three beam is used. By separating the electron beams of the book from each other structurally, it is possible to significantly improve the accuracy of the emission hole shift and the grid electrode spacing. The tilt angle that determines the electron beam emission angle, which is conventionally set for each grid electrode, is physically separated from these components, and the tilt angle is determined using another connecting component that sets the tilt angle.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a cathode / prefocus composite which is a main part of an electron gun for a color cathode ray tube according to the present invention. The three cathode / prefocus composites are connected, for example, to the main lens system shown in FIG. 3 with a predetermined tilt angle, and constitute an electron gun for a color cathode ray tube as a whole. In order to facilitate understanding of the invention, FIG. 1 shows a partially broken front shape, a plane shape, a bottom shape and a right side shape of the cathode / prefocus composite according to a normal drawing method. As shown in the figure, the cathode / prefocus composite 5 is divided into a first grid electrode G1, a second grid electrode G2, and an additional grid electrode GM, which are included in the prefocus system, into three parts, each of which is integrated with the corresponding cathode 1. It can be treated as an independent part. The cathode / prefocus composite body 5 is assembled by using insulating members 6 and 7 made of ceramic or the like. The cathode 1 is attached to the lower surface side of the insulating member 6. The cathode 1 is provided with a cylindrical outer cylinder member 8, a sleeve 9 inserted therein, and an oxide 10 which is formed on the top thereof and serves as an electron beam emission source. The outer cylinder member 8 is fixed to the central opening of the insulating member 6. A first grid electrode G1 having an emission hole E1 is attached to the upper surface of the insulating member 6. This first
The grid electrode G1 has, for example, a cap shape.
Further, the second grid electrode G2 is attached on the insulating member 6 via the spacer 11. The second grid electrode G2 has an emission hole E2 aligned with the emission hole E1 on the first grid electrode G1 side. The distance d12 between the first grid electrode G1 and the second grid electrode G2, which is an important factor for setting the cutoff voltage
Are precisely set by the spacer 11. The combination of the cathode 1 and the first grid electrode G1 assembled by using the insulating member 6 as a support is called an electron gun cathode structure, and can be generally produced as one component.

On the other hand, the second grid electrode G2 is previously fixed to the insulating member 7 made of glass or the like and made of ceramic or the like. In addition to the above-mentioned second grid electrode G2, an additional grid electrode GM is attached to the insulating member 7 with glass or the like. The emission hole E3 opened in the additional grid electrode GM and the emission hole E2 opened in the second grid electrode G2 are precisely aligned with each other. Further, the connecting member 12 made of metal is fixed on the additional grid electrode GM by welding or the like. As described above, the second grid electrode G2, the additional grid electrode GM, and the connecting member 12 can be assembled in advance as one component via the insulating member 7. The cathode / prefocus composite body 5 is completed by integrating the component having the insulating member 6 as the base and the component having the insulating member 7 as the base with the spacer 11. With such a configuration, it is possible to manufacture a unit in which the emission holes E1, E2, and E3 are hardly displaced from the first grid electrode G1, the second grid electrode G2, and the additional grid electrode GM.

FIG. 2 shows a mounting structure of the cathode / prefocus composite shown in FIG. (A) is a side view and (B) is a bottom view. A separately provided mounting component is used to mount the three cathode / prefocus composite bodies 5 at a predetermined tilt angle according to the emission angle of the electron beam. This attachment part is composed of a connecting member 12 and a substrate member 13. The substrate member 13 is commonly provided for the three cathode / prefocus composite bodies 5. On the other hand, the connecting member 12 is processed according to the inclination angles of the three cathode / prefocus composite bodies 5. Specifically, the top of the connecting member 12 is angled in advance by polishing or the like. In addition, this connecting member 12
Is attached to the upper surface of the additional grid electrode GM by welding as shown in FIG. In this way, the respective cathode / prefocus composite bodies 5 are attached to the substrate member 13 via the connecting member 12 to be integrated. Since the substrate member 13, the connecting member 12, and the additional grid electrode GM are all made of metal and fixed to each other by welding or the like, they are held at the same potential as a whole. In other words, the electrode member integrated with the substrate member 13, the connecting member 12 and the GM can be obtained.

[0010]

As described above, according to the present invention,
Three cathode / prefocus composites which are divided into three parts, that is, the first grid electrode G1, the second grid electrode G2, and the additional grid electrode GM which are included in the prefocus system, and which are integrally incorporated with the corresponding cathodes and separated from each other. Is provided. In addition, using the separately installed mounting parts,
Three cathode / prefocus composites are attached at a predetermined inclination angle according to the emission angle of the electron beam, and assembled into an electron gun for a color cathode ray tube. For this reason, even if the grid electrodes G1, G2, and GM are inclined, the emission hole deviation hardly occurs as compared with the conventional case. Thereby, the electron beam spot characteristics can be greatly improved. In this electron gun for a color cathode ray tube, each part is manufactured as a unit and finally assembled, so that the versatility of each part becomes high. In this connection, management of each component is facilitated. Furthermore, unlike the prior art, since precise accuracy such as the inclination angle and the position of the emission hole is not required for each grid electrode, the manufacturing cost of the electron gun for a color cathode ray tube can be reduced as a whole.

[Brief description of drawings]

FIG. 1 is a schematic view showing a main part of an electron gun for a color cathode ray tube according to the present invention.

FIG. 2 is a schematic side view and a bottom view showing an assembly structure of an electron gun for a color cathode ray tube according to the present invention.

FIG. 3 is a schematic block diagram showing an example of a conventional electron gun for a color cathode ray tube.

[Explanation of symbols]

1 ... Cathode, 2 ... Prefocus system, 3 ...
・ Main lens system, 5 ... Cathode / prefocus composite, 6 ... Insulating member, 7 ... Insulating member, 11 ...
..Spacer, 12 ... Connection member, 13 ... Substrate member, G1 ... First grid electrode, G2 ... Second grid electrode, GM ... Additional grid electrode

Claims (3)

[Claims] 1. A prefocus system that emits three electron beams at a predetermined emission angle, including three cathodes that generate three electron beams corresponding to the three primary colors, a plurality of grid electrodes, and the emission thereof. In an electron gun for a color cathode ray tube having a main lens system located on the side of the cathode, each grid electrode included in the prefocus system is divided into three parts, and the corresponding cathodes are integrally incorporated into three independent cathodes / pre-electrodes. An electron gun for a color cathode ray tube, which is provided with a focus composite body, and is equipped with mounting parts for mounting the three cathode / prefocus composite bodies at a predetermined inclination angle in accordance with the emission angle of each electron beam. . 2. The mounting component is processed according to the inclination angle of one substrate member provided in common for three cathode / prefocus composites and the three cathode / prefocus composites. The electron gun for a color cathode ray tube according to claim 1, comprising three connecting members, and each cathode / prefocus composite body is attached to the substrate member via the connecting members. 3. The prefocus system has a first grid electrode, a second grid electrode, and an additional grid electrode, and these three grid electrodes are each divided into three parts and integrated with a corresponding cathode. 2. The electron gun for a color cathode ray tube according to claim 1, wherein three cathode / prefocus composites are formed.